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1st International Earth Observation Convoy and
Constellation Concepts Workshop
Executive Summary and Detailed Report
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Amanda Regan
EOP-SFT-2014-02-1789
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Table of contents:
1 EXECUTIVE SUMMARY ..................................................................................................................... 5 1.1 Session 1: Key Science and Implementation Accomplishments from Existing Constellations ..................................... 5 1.2 Session 2: Future Landscape 2020 and Beyond ............................................................................................................. 6 1.3 Session 3: ESA Convoy Missions and Candidate Missions ............................................................................................ 6 1.4 Session 4: Technological Challenges............................................................................................................................... 6 1.5 Session 5: ESA EO Convoy Studies – Latest Results ...................................................................................................... 6 1.6 Session 6: Future Concepts ..............................................................................................................................................7 1.7 Session 7: Programmatic Challenges .............................................................................................................................. 8 1.8 Key Messages ................................................................................................................................................................... 9 1.8.1 Future Constellation Science and Measurements ........................................................................................................ 9 1.8.2 Constellation Lessons Learned .................................................................................................................................... 11 1.8.3 Highlighted Convoy Concepts ...................................................................................................................................... 12 1.8.4 Future Constellation Design ........................................................................................................................................ 14 1.9 Workshop Recommendations ........................................................................................................................................ 15 2 INTRODUCTION .............................................................................................................................. 16 2.1 Aims and Objectives ....................................................................................................................................................... 16 2.2 Committees ..................................................................................................................................................................... 16 2.3 Participants ..................................................................................................................................................................... 17 2.4 Programme ..................................................................................................................................................................... 17 2.5 Website ........................................................................................................................................................................... 17 2.6 On-line Feedback ............................................................................................................................................................ 17 2.7 Document Structure ....................................................................................................................................................... 17 3 APPLICABLE DOCUMENTS ............................................................................................................. 18 4 WORKSHOP OPENING REMARKS .................................................................................................. 18 5 SESSION SUMMARIES .................................................................................................................... 18 5.1 Session 1: Science and Implementation Accomplishments...........................................................................................18 5.1.1 Key Note Speech: The Value of Constellation Observing Systems based on A-Train Experience ............................. 19 5.1.2 Experience of GCOM-W1 Entering the A-Train .......................................................................................................... 19 5.1.3 The Morning Train ...................................................................................................................................................... 20 5.1.4 Experiences with Calipso and Future Opportunities .................................................................................................. 21 5.1.5 TerraSAR-add-on for Digital Elevation Measurements .............................................................................................. 21 5.1.6 The Cosmo-SkyMed Constellation Mission ................................................................................................................ 22 5.1.7 DMC Case Study - Benefits of Small Satellite Constellations..................................................................................... 22 5.2 Session 2: Future Landscape 2020 and Beyond ........................................................................................................... 23 5.2.1 ESA Earth Explorer Programme ................................................................................................................................. 23 5.2.2 Overview of Copernicus and its Evolution .................................................................................................................. 24 5.2.3 Copernicus Sentinel-1.................................................................................................................................................. 24 5.2.4 Copernicus Sentinel-2 ................................................................................................................................................. 25 5.2.5 Copernicus Sentinel-3 ................................................................................................................................................. 25 5.2.6 Copernicus Sentinels for Atmospheric Applications .................................................................................................. 26 5.2.1 Overview of EUMETSAT Missions and Applications ................................................................................................. 26 5.2.1 National Agencies Future Scenarios ........................................................................................................................... 27 5.2.1.1 The German Aerospace Center (DLR) ..................................................................................................................... 27 5.2.1.2 The Japanese Space Agency (JAXA) ........................................................................................................................ 28 5.2.1.3 The Italian Space Agency (ASI) ................................................................................................................................ 28 5.2.2 WMO Vision for the Space-based Observing System in the 2020’s .......................................................................... 28 5.3 Session 3: ESA Convoy Missions and Mission Candidates........................................................................................... 29 5.3.1 The FLEX Mission: Benefits and constraints of flying with Sentinel-3 ..................................................................... 29 5.3.2 End-to-End Mission Performance Simulators for EO Convoy Missions: Application to FLEX/Sentinel-3 Mission30 5.3.3 ESA’s Sentinel-5 Precursor: Mission & Operations Concept ..................................................................................... 30 Page 3/73
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5.4 Session 4: Technological Challenges .............................................................................................................................. 31 5.4.1 Constellation Lessons-Learned from the Cloudsat Experience .................................................................................. 31 5.4.2 End of Mission Planning Challenges for a Satellite in Constellation ......................................................................... 32 5.4.3 Similarities and Differences between the A-Train and the Proposed J-Train (JPSS) ............................................... 32 5.4.1 The Jason-1 EOL Case Study ...................................................................................................................................... 33 5.5 Session 5: EO Convoy Studies ....................................................................................................................................... 34 5.5.1 ESA Convoy Definition:............................................................................................................................................... 34 5.6 Overall ESA EO Convoy Studies Workshop Feedback ................................................................................................. 34 5.6.1 ESA EO Convoy Study - Ocean and Ice Applications ................................................................................................. 35 5.6.1.1 Identification of Measurement Gaps ....................................................................................................................... 35 5.6.1.2 Derivation of Convoy Concepts ................................................................................................................................ 37 5.6.1.3 Audience Feedback ................................................................................................................................................... 38 5.6.2 ESA EO Convoy Study Latest Results - Land Applications ........................................................................................ 39 5.6.2.1 Identification of Measurement Gaps ....................................................................................................................... 39 5.6.2.2 Derivation of Convoy Concepts ................................................................................................................................. 41 5.6.2.3 Audience Feedback .................................................................................................................................................... 41 5.6.3 ESA EO Convoy Study Latest Results - Atmospheric Applications ........................................................................... 43 5.6.3.1 Identification of Measurement Gaps (Chemistry and Composition) ...................................................................... 43 5.6.3.2 Identification of Measurement Gaps (Meteorology) ............................................................................................... 45 5.6.3.3 Derivation of Convoy Concepts ................................................................................................................................ 45 5.6.3.4 Audience Feedback ................................................................................................................................................... 46 5.7 Session 6 : Future Concepts .......................................................................................................................................... 47 5.7.1 Science and Applications from a Novel Ocean Surface Vector Wind Constellation .................................................. 47 5.7.2 The Role of Cloud and Precipitation Radars in Convoys and Constellations ............................................................ 48 5.7.3 Bi-static Radars with very Large Baselines: Potential Applications .......................................................................... 49 5.7.4 Passive Formation Flying ATI-SAR for Ocean Currents Observation: The PICOSAR Concept................................ 49 5.7.5 SAOCOM+ A Companion Satellite to the CONAE SAOCOM L-band SAR Mission .................................................. 49 5.7.6 CryoSat-2 and ICESat-2 - Overview of Possible Tandem Operations ....................................................................... 50 5.7.7 Global Frequent, High Spatial Resolution, Multispectral TIR Data – An Forthcoming EO Observational Gap ..... 50 5.7.8 Sentinel for Global Agriculture Requirements ............................................................................................................ 51 5.7.9 InfraRed Imaging Sensor Suite – Mission (IRIS-M) ................................................................................................. 52 5.7.10 The Next Generation Gravity Mission Constellation Concept ................................................................................... 53 5.7.11 The CYNGSS Constellation Mission ........................................................................................................................... 53 5.8 Session 7: Programmatic Challenges ............................................................................................................................ 53 5.8.1 Multi-Mission Constellations: Programmatic & Data Challenges ............................................................................. 53 5.8.2 The Afternoon Constellation Keys for Success ........................................................................................................... 55 5.8.3 A-Train - Implementation Lessons Learned .............................................................................................................. 56 5.8.4 The Orbital Registry Proposal ......................................................................................................................................57 5.9 Session 8: Concluding Remarks .................................................................................................................................... 58 6 WORKSHOP KEY MESSAGES ......................................................................................................... 59 6.1.1 Future Constellation Science and Measurements ...................................................................................................... 59 6.1.2 Constellation Lessons Learned .................................................................................................................................... 61 6.1.3 Highlighted Convoy Concepts ..................................................................................................................................... 63 6.1.4 Future Constellation Design ....................................................................................................................................... 64 7 WORKSHOP RECOMMENDATIONS ................................................................................................ 65 8 NEXT STEPS .................................................................................................................................... 66 9 APPENDIX 1 – WORKSHOP COMMITTEES ..................................................................................... 66 9.1 Organising Committee .................................................................................................................................................. 66 9.2 Science Committee ........................................................................................................................................................ 66 10 APPENDIX 2 – LIST OF PARTICIPANTS ......................................................................................... 67 11 APPENDIX 3 – WORKSHOP PROGRAMME.................................................................................... 69 Page 4/73
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1
EXECUTIVE SUMMARY
The 1st International Earth Observation Convoy and Constellation Concepts Workshop was held at ESAESTEC in Noordwijk in the Netherlands on 9th, 10th and 11th October 2013. The event was hosted by the
European Space Agency and co-organised with the National Aerospace and Space Administration
(NASA). An international science committee guided the workshop and a list of members can be found in
Appendix 1. A list of the workshop participants can be found in Appendix 2 and the workshop programme
can be found in Appendix 3.
The workshop comprised seven plenary sessions, which were both presentation and discussion based.
Professor Volker Liebig, Director of ESA Earth Observation Programmes provided opening remarks.
This document is the detailed workshop report, which includes the executive summary and detailed
summaries of all presentations and discussions (reference: EOP-SFT-2014-02-1789). The workshop
executive summary has also been written as a standalone document (reference: EOP-SFT- 2014-03-1801).
1.1
Session 1: Key Science and Implementation Accomplishments from
Existing Constellations
The first session showcased the science and implementation accomplishments of existing in-orbit
constellations being operated by multiple agencies. The missions presented included: the A-Train,
Morning Constellation, A-Train – Calipso mission, TanDEM-X, Cosmo-Skymed and the Disaster
Monitoring Constellation (DMC).
Graeme Stephens (NASA-JPL) gave the keynote speech. His talk focused on the A-Train and its
augmented science return. The present Afternoon Train (A-Train) comprises five satellites flying at 705
km: Aqua, Aura, Calipso, Cloudsat and GCOM-W1. NASA operates the Aqua, Aura and Cloudsat missions.
CNES operate the Calipso mission and JAXA operate the GCOM-W1 mission. The A-Train multi-sensor
approach generates new data sets and new science, which provides an in-depth integrated view of the
Earth System (with a particular emphasis on atmospheric measurements). The experience of the JAXA
GCOM-W1 satellite entering the A-Train was presented. The implication of GCOM-WI joining the A-Train
and the main lessons learned were highlighted. The Morning Constellation/train was presented
(forerunner to the A-Train). It proved that multiple sensors flying along the same path, which look at the
same scene with the same solar geometry coupled to extensive validation efforts, provide critical intercalibration and validation data streams. These data provided information redundancy and gap filling for
time series data products. The experience of Calipso flying in the A-Train with Cloudsat was also
presented. Lidar and passive radiometry are sensitive to different light-matter interactions and therefore
lidars can be used to validate and constrain passive retrievals. Active measurements should be seen as an
essential part of a cloud-aerosol-precipitation climate observing system. Long-term measurements are
required to identify, understand, and characterize cloud-climate feedback and characterize key modes of
climate variability.
The German Aerospace Center (DLR) presented the TerraSAR-X-add-on for Digital Elevation
Measurements (TanDEM-X) bi-static concept. The two X-band SAR satellites fly in a closely controlled
double helix formation with typical distances between 250 and 500 m. The main lessons learned and
critical elements were presented including: synchronization, calibration and mutual radiation. The
constellation capabilities were presented and applications were discussed.
The Cosmo-Skymed mission comprises four identical X-band SAR satellites. The dual use system is able
to support a number of applications including risk monitoring, ocean and ice monitoring, coastal
monitoring, forestry applications and urban planning. Application examples were highlighted including
observing the Louisiana oil spill, the Abruzzo earthquake and the Costa Concordia shipwreck.
Surrey Satellite Technology Ltd (SSTL) presented the Disaster Monitoring Constellation (DMC) series
comprises at present 5 optical satellites, which can provide daily global coverage. The capabilities of the
constellation were presented and applications were discussed. Future concepts were highlighted.
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1.2
Session 2: Future Landscape 2020 and Beyond
The second session focused the future in-orbit landscape. The ESA Earth Explorer programme was
presented. The Copernicus programme and its evolution was discussed including the dedicated space
segment known as the Sentinels satellite series. An overview of the EUMETSAT missions was provided
and discussed including Meteosat, MetOp, and JASON satellite series. Future series such as MetOp
Second Generation (MetOp-SG) and Meteosat Third Generation (MTG) were also highlighted.
National agencies such as DLR, JAXA and ASI provided overviews of their respective programmes,
detailed international cooperation efforts and presented possible future scenarios.
The World Meteorological Organisation (WMO) provided a vision of a space based observing system in
the 2020’s. It was highlighted that the WMO Integrated Global Observing System (WIGOS) focuses on the
integration of space and surface based observations. The Observing System Capabilities Analysis and
Review (OSCAR) activities were also highlighted.
1.3
Session 3: ESA Convoy Missions and Candidate Missions
This session focused the Sentinel-5 precursor mission and the ESA Earth Explorer mission candidate
mission known as Fluorescence Explorer (FLEX). FLEX is being designed to fly in convoy with Sentinel-3
(separated by 6 to 15 seconds). The science objectives focus on global mapping of vegetation fluorescence,
vegetation health status / stress identification, anthropogenic impacts (land use changes) etc. The FLEX
end-to-end mission performance simulator was also highlighted.
Sentinel-5 Precursor (S5P) mission was also presented. It will be the first spacecraft in series of
atmospheric observing systems within the Copernicus programme. It is a preparatory mission before the
launch of Sentinel-5 on-board MetOp-SG. S5P is scheduled for launch in 2015 and it is planned that S5P
shall follow the ground track of the American JPSS satellite (13:30 LT).
1.4
Session 4: Technological Challenges
This session focused on the technological challenges of flying spacecraft together. NASA lessons learned
in general were identified and discussed. These points addressed both lessons learned by the A-Train and
constellations in general. The end of mission planning challenges for the A-Train was discussed and the
Cloudsat battery anomaly was highlighted. The A-Train control box methodology was presented which is
a simple but effective way of safely controlling the separation between the A-Train spacecraft along the
orbit. A-Train flight dynamics and associated challenges were identified and presented and possible
options for future concepts were discussed. The Jason-1 End of Life Case Study was also presented. EOL
issues were highlighted which require codes of practice to be agreed on an agency and inter-agency level
prior to the event including establishing a means to coordinate and communication information.
1.5
Session 5: ESA EO Convoy Studies – Latest Results
The European Space Agency (ESA) is funding three exploratory activities (known as the EO-Convoy
studies). The aim of these studies is two fold: Firstly, to identify scientific and operational objectives and
needs which would benefit from additional in-orbit support. Secondly, to identify and develop a number
of cost-effective convoy concepts (comprising additional missions flying with European operational
satellites), which would meet these identified objectives and needs. Each EO-Convoy study is dedicated to
a specific theme:
• Study 1: Ocean and Ice
• Study 2: Land
• Study 3: Atmosphere
The user needs and the derived convoy concepts were presented and discussed. The user needs study
documents can be found on the workshop website http://congrexprojects.com/2013-events/13m12/home
the user needs focused on the extension of established spectral and spatial scales. For each study a
number of convoy concepts were identified. These are listed below.
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Convoy Satellite
Anchor Satellite
Study 1: Ocean and Ice Convoy Study
Passive C-band SAR
+
Sentinel-1 (selected for further study)
Active C-band SAR (InSAR)
+
Sentinel-1
X/Ku-band SAR
+
Sentinel-1
Thermal Infrared (TIR)
+
Sentinel-1
VIS/NIR/SWIR
+
Sentinel-1
L-band SAR
+
Sentinel-1
Laser altimeter
+
Sentinel-3 (selected for further study)
Passive microwave (L-band)
+
Sentinel-3
Ku-band Scatterometer
+
MetOp-SG (selected for further study)
Passive Microwave (L-band)
+
MetOp-SG
Passive C-band SAR
+
Sentinel-1 (selected for further study)
L-band SAR
+
Sentinel-1
MIR/TIR multi-spectral imager
+
Sentinel-2 (selected for further study)
Sparse array L-band SAR
+
Sentinel-1
W-band conical scanner
+
Sentinel-2
High resolution TIR
+
Sentinel-2 (selected for further study)
Multi-angle imager
+
Sentinel-2
S-band SAR
+
Sentinel-1
Broadband light source
+
MetOp-SG (S5)
UV-VIS multi-angle profiler/ mapper
+
MetOp -SG (3MI) (selected for further study)
UV/Vis spectrometer
+
Sentinel-3 (SLSTR)
NO2 Lidar
+
S5P
3 micron spectrometer
+
MetOp (IASI, S5) (selected for further study)
Aerosol lidar
+
MetOp -SG (3MI/UVNS)
CarbonSat (EE8) + FLEX (EE8) + BIOMASS (EE7)
+
Sentinel-3 (SLSTR)
Lidar
+
MetOp -SG (IR/MW sounders)
Multi-angle thermal infrared
+
MetOp -SG
Extended RO
+
MetOp -SG
Cloud Profiling Radar
+
MetOp -SG
Multi-wavelength cloud aerosol lidar
+
MetOp -SG (Imagers)
Study 2: Land Convoy Study
Study 3: Atmosphere Convoy Study
+
MetOp -SG (Imagers)
Cloud Profiling Radar + Multi-wavelength cloud aerosol lidar
Table 1 List of Convoy concepts identified and assessed during all three Convoy Studies
1.6
Session 6: Future Concepts
Session 6 comprised three sub-sessions focusing on SAR concepts, thermal infrared concepts and future
concepts in general. The theme for all the presentation was a need for higher temporal and spatial
measurements to capture dynamic Earth system phenomena and the characterisation of Earth system,
element interactions e.g. Land – Atmosphere, Ocean – Atmosphere etc.
Future radar concepts were discussed. The next generation of atmospheric radars should be defined in
the context of multi-instrument observations in order to mitigate the ambiguities affecting atmospheric
remote sensing techniques. Atmospheric radars also measure the surface and with advanced processing
and re-tuning other phenomena can be measured. This would lead to different user communities using
the same instrument to measure different phenomena.
Measurements of convective processes on a global scale were highlighted as an area where space-borne
measurements would be valuable.
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Geo-stationary infrared imaging satellites coupled with LEO imaging radar satellites provide
measurement synergy e.g. GEO-IR satellites measure cloud shell/skin properties and the radar
measurements from LEO can penetrate the cloud and measure phenomena occurring inside the cloud –
when these measurements are coupled together then overall cloud processes can be better understood.
The use of active instruments for Earth system measurement was highlighted. A possible convoy
configuration comprising CryoSat-2 and ICESat-2 in the post 2016 time frame was presented. Bi- and
multi-static SAR concepts were presented including the SAOCOM companion satellite and DLR PicoSAR
concept.
The need for high-resolution thermal infrared data was emphasized. Current TIR instruments will soon
be beyond their nominal lifetimes with strong possibility of a data gap later this decade. The NASA
Hyperspectral Imager (HyspIRI) mission was presented. Architectures for future missions focused on
agriculture were identified. High-resolution thermal infrared sensors were also presented e.g. the IRIS-M
payload comprising high-resolution capabilities in the thermal infrared. Use of a high-resolution thermal
infrared instrument was emphasized to complement Sentinel-2 (extend capability beyond SWIR) and/or
Sentinel-3 (higher resolution TIR to act as a zoom lens to complement the TIR at 1 km).
The Next Generation Gravity Mission (NGGM) was presented by ESA, comprising more than one satellite
and international cooperation between ESA and NASA was particularly highlighted.
The Cyclone Global Navigation Satellite System (CYGNSS) is the NASA Earth Venture Mission selected in
2012. This constellation mission (eight satellites) uses GPS signals to understand the coupling between
ocean surface properties, moist atmospheric thermodynamics, radiation, and convective dynamics in the
inner core of a tropical cyclones.
1.7
Session 7: Programmatic Challenges
This session focused on the programmatic details of setting up and operating constellations. The A-Train
experience was presented. A-Train data from the individual sensors can be used together to exploit data
synergies e.g. near-simultaneity and different observation geometries. Measurement synergy has enabled
improved science product quality. This requires sharing of data at a low level e.g. radiance level (“level 1”).
Multi-satellite missions must be designed and built using a common set of consolidated requirements
Each A-Train mission was designed with stand-alone mission objectives and with identified synergies
with other mission to enable additional science e.g. Cloudsat and Calipso have individual science
objectives but together provide augmented science return. Each mission maintains its independence but
the operations of one mission cannot interfere or jeopardize the safety of the other mission. A
constellation level management framework is critical to the safe operation of the A-Train. For the A-Train
this is known as the Mission Operation Working Group (MOWG). Constellation level documentation and
information exchange is essential and the A-Train uses the Constellation Coordination System (CCS),
which is on-line tool enabling information exchange information, e.g. mission status and orbital data. An
open data policy is essential. A full science benefit cannot be achieved and the investment of flying a
constellation cannot be realized without an open data exchange. Careful calibration and validation on a
constellation level must also be addressed. Data merging, data management and data storage are critical
issues requiring resource allocation and careful definition.
Specific A-Train case studies were presented including the Parasol mission leaving the A-Train, the
Cloudsat mission re-entering the A-Train and Aqua satellite (A-Train anchor satellite) inclination
maneuver changes.
As more satellites are launched into space the idea of an international registry to mitigate close
approaches and collisions was presented. An international registry would lead to joint working groups,
information sharing, and joint analysis. In the short term NASA would like to collect point of contact
information from other operators to resolve these issues. Possible implementation activities were
presented.
Future convoys and constellations require a framework to establish expectations. This includes e.g.
international agreements, constellation level documentation and data sharing, agency activities and calls
which encourage convoys and constellations, operational configurations which allow safe multi-satellite
flying, standardized policies and procedures which are independent of individual missions. There also
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needs to be a basis for committing agency resources to constellation activities with dedicated constellation
level management and a promotion of multi-mission research.
1.8
Key Messages
The figure below provides an overview of the key messages from the workshop. The key messages are
identified and discussed in sections 1.8.1 to 1.8.4.
Table 2 Workshop Key Messages
1.8.1
Future Constellation Science and Measurements
Key Message 1.1: Constellations must focus on cross cutting science
• Large cross cutting science problems (e.g., interactions between Earth science domains and
Earth science cycles such as energy, water and carbon) need to be identified and characterised
and any derived constellation concepts need to be mapped to this analysis.
• Constellations provide a unique opportunity to measure the interfaces and interactions
between Earth Science Domains.
Key Message 1.2: Constellations can exploit complementary measurements
• Cross-comparison of the same geophysical product using multiple observation techniques and
retrieval methods is essential to understanding the phenomena being observed.
• Active and Passive instruments
o Active and passive instruments provide complementary measurements. Using both
types of instruments together can provide excellent opportunities for cross comparison
and error checking.
o Measuring the same phenomena using different instruments based on different physics
leads to increased confidence that the process being measured is being properly
understood.
• Simultaneous measurements (separated in time, space and viewing direction etc.)
o Identical/complementary measurements separated in time / space / both following a
reference ground track to capture dynamics processes.
o Measurement from e.g. limb and nadir viewing directions can be invaluable to
characterise processes and phenomena occurring in three dimensions e.g. Earth
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Explorer 8 candidate mission PREMIER and MetOp.
Instruments in LEO and GEO
o Instruments in LEO and GEO can provide highly complementary measurements.
Key Message 1.3: Long term sustainable scientific data
•
•
The Earth System is a highly complex system with processes and phenomena occurring over a
wide range of spatial and temporal scales. Multi-satellite data sets show that these processes
and phenomena are all interlinked and fast processes project onto the longer scales. The key is
to understand how the system evolves through sustained and long-term measurements and not
just by providing short-term intermittent measurements.
The key is to understand how the system evolves through sustained and long-term
measurements. The design of scientific missions as independent experiments with a relatively
short life time and lack of firmly planned continuity affects the development of potential
constellations, which may be built-up in time.
Key Message 1.4: High resolution measurements
• Complex and dynamic phenomena require high-resolution measurements in both the spatial
and temporal domains.
• Higher resolution sensors are needed to capture smaller scales and characterise dynamic
cycles.
• Sub-daily revisit (which is possible with multiple satellites) is needed for many applications to
capture phenomena such as diurnal cycles etc.
• Examples requiring high resolution observations were cited across all Earth Science domains
e.g. the measurement of mesoscale and sub-mesoscale oceanographic features, improved wind
measurements, ocean and particularly coastal surface currents, land cover complexity and
dynamics (including cryosphere), surface energy balance, urban applications, water including
snow, snowfall and sea-ice, etc.
• Higher resolution measurement supports improved model development.
• Three-dimensional measurements are needed to comprehensively capture dynamic and
complex processes. One example cited was 3D vector motion.
Key Message 1.5: Constellation level data products
•
•
Constellation level data products must be identified and resources put in place to generate such
products.
•
Cross-comparison of the same geophysical product using multiple observation techniques and
retrieval methods is essential to understanding the phenomena being observed.
Merging data from multiple sensors with different observation techniques in terms of
geometry, co-registration etc. is not a trivial task and resources must be allocated for this task.
Key Message 1.6: Calibration
• Calibration is critical to ensure data consistency over long time series particularly for climate
monitoring.
• Robust calibration enables effective data merging from various sources and it allows data gaps
to bridged.
• One instrument acting as a reference calibrator can be used to enhance the return of other
instruments.
Key Message 1.7: Co-registration
• The issue of co-registration of multiple sensors flying in the train is a complex problem and
should not be overlooked. Issues such as differing sensor resolution and swath width must be
addressed including the problem of cloud movement and characterization.
Key Message 1.8: Instrument retrieval algorithms
• Instrument retrieval algorithms should be developed and reviewed with the same rigor as the
instrument engineering development.
•
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1.8.2
Constellation Lessons Learned
Key Message 2.1: Cooperative sensing requires a paradigm shift
• Flying in a constellation requires a shift in thinking from mission level to constellation level.
Acknowledgement that certain mission activities may impact other missions e.g. data sets, orbit,
downlink etc. These considerations need to be identified, communicated, managed and resolved
on a constellation level
• Missions flying in constellation cannot be considered in isolation. Cooperative sensing may add
some complexity and cost but ultimately it can provide great benefits and augmented science
return.
• Any developed mission must be able to stand-alone in terms of its science objectives and provide
augmented science return when flying together with other missions.
Key Message 2.2: Agency support and effective management at constellation level
• Strong agency support and vision are essential.
• Effective management at the constellation level is critical coupled to a coherent management
structure with clear decision boards
• For future convoys and constellations a framework is needed to establish expectations. This
includes e.g. international agreements and data sharing, agency activities and calls which
encourage convoys and constellations, operational configurations which allow safe multisatellite flying, standardized policies and procedures which are independent of individual
missions.
• There also needs to be a basis for committing agency resources to constellation activities with
dedicated constellation level management and a promotion of multi-mission research.
• Constellation level activities require careful planning and agreement e.g. manoeuvre campaigns
etc.
Key Message 2.3: Orbital considerations
• Definition of the reference ground track is critical.
• The use of control boxes or similar with buffers to maintain constellation safety is critical.
• Definition of the phasing at the poles is important to prevent satellite conjunctions
Key Message 2.4: Spacecraft Implications (highlighted & discussed during the workshop)
• BOL and EOL planning
o Mission objectives must drive the mission until the spacecraft health reaches a limit.
There is a time when the satellite needs to de-orbit from the constellation. BOL and EOL
planning must be identified, assessed and agreed at an early stage of development and
then periodically iterated as the spacecraft moves through its development and in-orbit
phases.
• Orbit choice
o The orbit choice may be a compromise between instrument capabilities and the science
benefits of flying in a constellation e.g. active instruments flying in a constellation at a
higher orbit.
o Definition of the reference ground track is critical.
o For EOL / de-orbit from the constellation an alternative orbit should be identified
before launch.
• Propellant
o Typically more propellant is required when flying in a constellation:
o Safe orbit insertion
o Safe in-orbit manoeuvres
o Safe de-orbit
o For the satellites operating within a constellation an understanding of the fuel budget is
critical e.g. consumption, use of fuel for unforeseen orbit manoeuvres.
• Flexible manoeuvre capability
o Flexible maneuver capability is strongly advised e.g. retro-firing capability
• Spacecraft modes
o For each satellite flying closely together within constellation, a full understanding of all
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possible spacecraft modes is seen as critical to prevent unforeseen close approaches e.g.
propulsive safe modes etc.
• Communication between satellites in the constellation
o Additional resources may be needed e.g. transponders etc. to communicate with other
satellites in the constellation.
• Mass memory
o Depending on the design more mass memory may be needed.
• Interference
o Mutual irradiation from satellites flying together can be a design constraint.
• Uplink and downlink design
o When satellites are flying closely together the uplink and particularly the downlink must
be carefully assessed (particularly for satellites with high data rate sensors on-board).
• Programmatic impact
o When different satellites are flying together the programmatics of one satellite may
impact another particularly if one satellite is reliant on the measurements of another e.g.
different agency development cycles etc.
Key Message 2.5: Constellation can provide mission flexibility
• Constellations provide flexibility to address foreseen and unforeseen issues such as sun glint
mitigation etc. e.g. the spacecraft can be separated and re-aligned etc.
Key Message 2.6: Established constellation agreements, policies and codes of practice
• For future convoys and constellations a framework is needed to establish expectations.
• Establishment of coherent constellation level agreements, policies and code of practice must be
signed by all parties addressing all phases of the mission lifetime e.g. orbit insertion, operation,
end of life (EOL) operations.
• A robust and transparent process for constellation issues is critical e.g. BOL, change requests,
EOL etc. Coordination rules, processes and plans have to be flexible and adaptable and
communication between the mission teams is critical.
• Establish what data should be shared and a means to coordinate and communication
information.
• Agreements are essential to ensure that there is a mutual understanding of the terms governing
the inter-agency relationship e.g. for the A-Train Contractor/private industry personnel
negotiate Technical Assistance Agreements, which are then signed by the individual mission
teams.
• A basis is required for committing agency resources to constellation activities with dedicated
constellation level management and a promotion of multi-mission research.
Key Message 2.7: Understanding differences when working in cooperation
•
Cooperation with other agencies (either at a national or international level) requires an
understanding of different cultures, different methods of working, different development cycles,
different time zones and different motivational factors. These aspects should not be under
estimated.
1.8.3
Highlighted Convoy Concepts
Key Message 3.1: Measurement combinations provide complementary measurements
• A suite of instruments is needed to measure from the top of atmosphere (TOA) to ground level.
• The A-Train is based on measuring the same phenomena with different sensors based on
different physics. This multi-sensor approach provides augmented science return across
different observations, platforms and sensors. This approach enables data products to be
independently calibrated.
• One example discussed focused on Calipso-Caliop (Lidar) and Aqua-MODIS, which provide
atmospheric retrievals based on different physics. Active instruments can validate the retrievals
of passive instruments. One example discussed focused on Calipso-Caliop (Lidar) and AquaMODIS, which provide atmospheric retrievals based on different physics. The Aqua-MODIS
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•
retrievals rely on inputted light scattering models and these can be calibrated using the lidar on
board the Calipso spacecraft.
Measuring phenomena with different sensors based on different physics and obtaining similar
results provides confidence that the processes and phenomena are being well understood.
Key Message 3.2: Identical or complementary measurement combinations separated in
time / space / viewing direction
• Identical/complementary instruments can be separated in time (along or across track) and / or
space (distributed spacecraft etc.) to characterise dynamic phenomena
• Different viewing directions e.g. limb and nadir can be used to characterise processes and
phenomena occurring in three dimensions e.g. Earth Explorer 8 candidate mission PREMIER
(Limb) and MetOp (Nadir).
Key Message 3.3: Specific Convoy Concepts which were highlighted (non-exhaustive list)
• Laser and radar combinations
o Laser and radar instruments flying together in a coordinated way provide
complementary measurements, which, could provide cross cutting science and address
applications across numerous Earth Science domains. Examples included
Cloudsat/Calipso (A-Train), and the possible tandem operations of Cryosat-2/ Icesat-2.
• Higher resolution thermal infrared < 60 m – 250 m
o Measurements in the thermal infrared spectral range are needed for numerous Earth
Science domains.
o Current in-orbit TIR instruments e.g. Landsat-8-TIRS, Aqua/Terra-MODIS, TerraASTER etc. all have limited lifetimes and if replacements are not launched then there
will be a strong possibility of a data gap later this decade.
o Multiple TIR channels are needed to separate emissivity and temperature.
o Mid infrared and thermal infrared are needed to measure fires and thermal hot spots
(with additional visible channels for context).
o To measure thermal anomalies a high dynamic range is required to mitigate detector
saturation.
o There is cross crossing science between land and atmospheric sounding communities
regarding infrared imagery
o Flying a thermal infrared imager with Sentinel-2 was highlighted.
• Bi-static and multi-static SAR
o Passive SAR concepts flying together with active SAR satellites were highlighted: single
pass and repeat pass interferometry in L-band (SOACOM-CS) and C-band (ESA EO
Convoy, DLR PicoSAR concept).
o Constellations of active SARs flying together. The TanDEM-X mission was presented
and future concepts such as bi-static SAR for applications such as ocean current
observation, soil moisture measurement, urban area characterisation and forest
tomography were also highlighted.
• Multi-frequency SAR
o Multi-frequency SAR measurements (SAR satellites of different frequencies flying
together) were discussed as a way to increase the dynamic range and due to different
responses build up a picture of phenomena being measured.
• Next generation Atmospheric Radar Satellites
o The next generation of atmospheric radars should be defined in the context of multiinstrument observations in order to mitigate the ambiguities affecting atmospheric
remote sensing techniques.
o Atmospheric radars can also measure the surface and with advanced processing and retuning other land surface phenomena could be measured. This would lead to different
user communities using the same instrument.
o A backscatter lidar to provide support data for other missions
• Earth Explorer Candidate Missions not selected were highlighted:
o PREMIER flying with MetOp
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•
o CoReH2O (X/Ku-band SAR) flying with Sentinel-1
A backscatter lidar to provide support data for other missions
o The lidar can provide support data for existing missions to establish scene
characteristics e.g. remove unwanted clutter in the actual measurement such as the
presence of thin cirrus clouds
Key Message 3.4: Measurement synergy concepts
•
LEO and GEO concepts flying together
o Coordinated GEO and LEO satellites combinations were highlighted as a potentially
powerful technique to capture dynamic processes on global and local scales.
o One example: Use GEO IR satellites /LEO radar satellites to build up a picture of
global convection. The GEO-Infrared satellites measure cloud shell/skin properties
and the radar can measure phenomena inside the cloud.
1.8.4
Future Constellation Design
Key Message 4.1: Measurement Synergy
Missions can no longer be designed in isolation. When new missions are developed the existing
landscape and possible measurement synergies must be considered for augmented science
return. Constellation aspects should be highlighted in Agency calls e.g. ESA Earth Explorers etc.
Key Message 4.2: Copernicus Sentinels
• Copernicus represents a stable long-term programme for Earth Observation into 2030s. The
Copernicus Sentinels are a constellation infrastructure and possible synergies with other
systems should be explored. The Sentinels do not fly in convoy with each other but further
activities focused on synergetic use of Sentinel data and data augmentation on a constellation
level should be considered. Aspects such as Systems of Systems can be considered.
Key Message 4.3: Anchor Satellites
• Satellites such as EOS-Aqua, Landsat series and the planned Sentinels can provide long-term
anchor points for future constellations.
Key Message 4.4: Orbit Choice
• Constellation participation depends upon the attractiveness of the orbit.
Key Message 4.5: Data policy, data management and distribution
• Data policies vary across nations and national agencies therefore it is important to establish the
data policies at an early stage.
• The data combination, processing, distribution and storage for a constellation must be carefully
assessed and resources must be allocated.
• Merging data from multiple sensors with different observation techniques in terms of geometry,
co-registration etc. is not a trivial task and resources must be allocated for this task.
• Full science benefit cannot be achieved and the investment of a flying a constellation cannot be
realized without an open data exchange.
Key Message 4.6: Replenishment Strategy
• Any constellation must have a viable and robust replenishment strategy
Key Message 4.7: International Cooperation
• International cooperation is essential. Constellations enable international cooperation to ensure
an optimum return / effort ratio.
•
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1.9
Workshop Recommendations
Based on the results and discussion at the 1st International Earth Observation Convoy and Constellations
Workshop, a number of recommendations were identified for future areas of further study. These can be
seen below
Recommendation – Constellations to focus on cross cutting science
• The convoy studies focused on extending scales of known parameters. It was recommended to
open out this analysis away from incremental deltas related to known parameters and move
towards broader cross cutting measurement gaps which are needed to comprehensively
understand the Earth system e.g.:
o Characterising the interfaces and interactions between the various Earth system domains
e.g. cycles.
o Identifying and understanding the various flux exchanges and their impact on the Earth
System.
• Therefore, future science activities must focus on the interactions, interfaces and
connections between the classical Earth Science domains. These activities can provide a
roadmap for future constellations. One example provided was high-resolution evapotranspiration
measurement, which essentially connects the water cycle and the surface energy balance. This
approach would also benefit model assimilation e.g. land surface, land-atmosphere models.
Recommendation – Cooperative sensing
• There needs to be a fundamental paradigm shift towards ‘cooperative sensing’ when
defining new missions. New missions cannot be designed in isolation. At present Agencies select
missions often on a case-by-case basis.
•
A formal programmatic framework is required for constellation missions. This framework would
include elements such as rules for international or inter-agency cooperation, data policy,
information exchange etc.
Recommendation – Anchor Satellites
Copernicus is a constellation in itself. The Sentinels and other missions such as Landsat follow on
concepts etc. can act as anchor satellites for additional missions.
Recommendation – Identified Convoy Concepts
A number of convoy concepts were highlighted. These included:
• A combination of passive and active measurements provides the most comprehensive
science return, due to synergy in information content. Laser and radar synergies were particularly
highlighted.
• Higher resolution thermal infrared (< 60 m – 250 m).
• Bi-static and multi-static SAR (C-band and L-band were highlighted)
• Multi-frequency SAR measurements comprising SAR satellites of different frequencies
flying together.
• The next generation atmospheric radars should be defined in the context of multiinstrument observations in order to mitigate the ambiguities affecting atmospheric remote
sensing techniques
• Earth Explorer Candidate missions which were not selected were highlighted e.g.:
o PREMIER (limb view) with flying with MetOp (nadir view)
o CoReH20 (X/Ku-band SAR) flying with Sentinel-1 (C-band SAR)
Recommendation
• It was highlighted that one area of improvement for future observing systems is the ability to
capture dynamic small-scale processes. For these types of observations high spatial
resolution and high temporal resolution were identified as critical. Examples included heat
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•
flux characterisation, velocities, diurnal cycles etc.
A good sampling is required to capture dynamic behaviour and this requires combining multipoint measurement from convoys, constellations and other observing system such as GEO
satellites. Activities focusing on combining LEO and GEO measurements were highlighted.
Recommendation – Multi-Agency Constellation Handbook / Guidelines
Produce a multi-agency constellation implementation handbook / set of guidelines based on lessons
learned. This document can then become an agreed starting point for future international cooperation.
2
INTRODUCTION
The 1st International Earth Observation Convoy and Constellation Concepts Workshop was held at ESAESTEC in Noordwijk in the Netherlands on 9th, 10th and 11th October 2013. The event was hosted by the
European Space Agency (ESA) and co-organised with the National Aerospace and Space Administration
(NASA). Many national space agencies were also actively involved including: ASI, CNES, DLR and JAXA.
An international science committee guided this workshop and a list of members can be found in Appendix
1. In total over 120 people attended the workshop and the participants’ list can be found in Appendix 2.
The workshop programme can be found in Appendix 3.
The workshop comprised seven plenary sessions, which were both presentation and discussion based.
Professor Volker Liebig, Director of ESA Earth Observation Programmes provided opening remarks. Dr
Graeme Stephens from NASA-JPL gave the keynote speech, which focused on the value of constellation
observing systems based on A-Train experience. An executive summary and specific summaries of the
opening remarks, keynote speech, presentations, talks, discussions and ideas are included in this
document. Key points are highlighted. Workshop recommendations can be found in Section 6.
2.1
Aims and Objectives
The aim of the workshop was to collect recommendations for a future constellation studies and activities
development roadmap. This workshop was an opportunity to provide input for future agency level
constellation related studies and activities. The specific objectives include:
1. To collect recommendations for a future constellation studies and activities development
roadmap.
2. To identify and discuss science and application opportunities from Earth observation
constellations across all Earth science domains including the interactions between these domains
• The key science accomplishments of existing constellations
• Identification of observational gaps, novel observations, enhanced Earth Observation
products and science questions across all Earth science domains, which can be effectively
addressed by satellite convoys and constellations.
3. To present existing experience of Earth Observation convoys and constellations e.g. international
considerations, orbital aspects and data management.
4. To present the results of the ESA EO Convoy Studies in terms of science gaps and derived
concepts:
• Ocean and Ice EO Convoy Study
• Land EO Convoy Study
• Atmosphere EO Convoy Study.
5. To discuss the challenges of convoys and constellations e.g. international cooperation, sensor and
measurement considerations, orbital aspects and data management.
6. To discuss future EO convoy and constellation concepts and satellite coordination options in
relation to identified science questions and observational gaps.
2.2
Committees
The ESA-NASA organising committee can be found in Appendix 1. The workshop science committee
comprised over twenty members from eleven countries. A list can also be found in Appendix 1.
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2.3
Participants
Over 120 delegates registered for the meeting including space agencies, industry and universities. A list of
the registered participants can be found in Appendix 1. Some colleagues also joined the workshop via
Webex. This is highlighted in the programme (Appendix 3)
2.4
Programme
The final programme can be found in Appendix 2.
2.5
Website
The workshop website can be found at the following address:
http://congrexprojects.com/2013-events/13m12/home
The workshop website includes the final programme, proceedings and presentations.
2.6
On-line Feedback
The website includes a feedback section with a dedicated email address.
To provide feedback please write to: [email protected]
2.7
Document Structure
Section 1
This section provides a workshop executive summary.
Section 2
This section provides an introduction, and the workshop aims and objectives. It provides supporting
information and context for future sections.
Section 3
This section includes all applicable documents
Section 4
This section provides an overview of the opening remarks provided by Volker Liebig, Director of the ESA
Earth Observation Directorate.
Section 5
This section provides an overview of the workshop sessions. A summary of each presentation is included
and highlights from the discussion following each presentation are also provided where appropriate. The
key points from each presentation are highlighted.
Workshop Sessions
• Session 1: Key Science & Implementation Accomplishments from Existing Constellations
• Session 2: Future In-Orbit Landscape: 2020 and Beyond
• Session 3: ESA EO Future Convoy Missions and Future Convoy Candidate Missions
• Session 4: Technological Challenges
• Session 5: ESA EO Convoy Studies latest results
Ø Ocean and Ice Applications
Ø Land Applications
Ø Atmospheric Applications
• Session 6: Future Concepts enabling Science and Application Opportunities
• Session 7: Programmatic and Data Challenges
• Session 8: Conclusions
Section 6
This section provides overall conclusions
Section 7
This section provides some recommendations for future activities and studies.
Section 8
This section details the next steps.
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Appendix 1
This section provides an overview of the committee member who made this workshop a reality.
Appendix 2
This section provides the workshop participants list
Appendix 3
This section provides an overview of the workshop programme.
3
APPLICABLE DOCUMENTS
AD 1
“The Changing Earth – New Scientific Challenges for ESA’s Living Planet Programme”
(ESA/SP-1304)
Results of EO Convoy Land Applications Workshop www.le.ac.uk/sentinel-convoy-land.
EO Capabilities, Gaps and Opportunities (ESA EO Convoy Ocean and Ice), EOSC.ASU.RP. 001,
Issue 1, 2012. http://congrexprojects.com/2013-events/13m12/home
Sentinel Convoy for Land Processes Task 1: Critical Review and Gap Analysis, SCL-ULE-TN02_V5.0, Issue 5, February 2012 http://congrexprojects.com/2013-events/13m12/home
EO Atmosphere Capabilities, Gaps and Opportunities, EOCA.ASU.SY.RP00001, Issue 1,
January 2013. http://congrexprojects.com/2013-events/13m12/home
EO Convoy Mission Concept Definition Report, EOCA.ASU.SY.RP.00003, Issue 1, July 2013.
(Atmosphere Applications Study)
Observing Systems Capability Analysis and Review Tool, OSCAR http://www.wmosat.info/oscar/
Updating the Scientific Challenges of ESA’s Living Planet Programme - Science Strategy - A
Proposal by the ESA Earth Science Advisor Committee
http://www.livingplanet2013.org/documents/Scientific Challenges.pdf
Sentinel Convoy Workshop Updating the Scientific Challenges of ESA’s Living Planet
Programme - Science Strategy - A Proposal by the ESA Earth Science Advisor Committee
http://www.livingplanet2013.org/documents/Scientific Challenges.pdf
AD 2
AD 3
AD 4
AD 5
AD 6
AD 7
AD 8
AD 9
4
WORKSHOP OPENING REMARKS
Volker Liebig, Director of ESA Earth Observation Directorate opened the workshop. Maurice Borgeaud,
Director of Earth Observation Science and Applications Department also provided welcoming remarks.
Both speakers expressed their hope that by bringing a large and diverse group together to focus on
synergies, convoys and constellations for Earth observation that ideas for the future could be
communicated and discussed and that given the present economic climate everyone must work more
effectively together in partnership. Volker Liebig emphasized existing experience such as the A-Train and
TanDEM-X. He spoke about ESA plans such as the Swarm mission, Sentinel-5 Precursor (S5P) mission
following the ground track of Suomi-NPP and the Fluorescence Explorer (FLEX) candidate mission being
designed to fly with Sentinel-3. He mentioned ESA and NASA plans for a next generation gravity mission
based on GRACE and GOCE expertise. Beginning next year the first Sentinel will be launched leading to
an in-orbit capability by the end of the decade of more than seven satellites (including S5P). The
Copernicus Sentinels will provide a new era of permanent monitoring. He highlighted that the Sentinels
satellites could provide great potential for measurement synergies. He emphased that it is important to
work efficiently and effectively given these difficult economic times and design and build new missions
more cost effectively through cooperation and partnership.
5
SESSION SUMMARIES
5.1
Session 1: Science and Implementation Accomplishments
The aim of the first session was to present the existing constellation experience. Due to the US
government shutdown two presenters could not join the workshop in person but sent presentation slides
to be presented, or second authors presented the slides.
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5.1.1
Key Note Speech: The Value of Constellation Observing Systems based on ATrain Experience
Presenter: Graham Stephens, NASA-JPL
The present Afternoon Train (A-Train) comprises five satellites flying at 705 km: Aqua, Aura, Calipso,
Cloudsat and GCOM-W1. OCO-2 will join the constellation in 2014. NASA operates the Aqua, Aura and
Cloudsat missions. CNES operate the Calipso mission and JAXA operate the GCOM-W1 mission. These
missions follow each other in a train with Aqua acting as the anchor satellite. The A-Train is based on
measuring the same phenomena with different sensors based on different physics. This multi-sensor
approach provides augmented science return across different observations, platforms and sensors. This
approach enables data products to be independently calibrated. Ultimately, the overall science return of
the A-Train constellation is greater than the sum of its parts. One example discussed focused on CalipsoCaliop (Lidar) and Aqua-MODIS, which provide atmospheric retrievals based on different physics. The
Aqua-MODIS retrievals rely on inputted light scattering models and these can be calibrated using the
lidar on board the Calipso spacecraft.
Measuring phenomena with different sensors based on different physics and obtaining similar results
provides confidence that the processes and phenomena are being well understood. Combining different
observations offers new insights into the physical world, which can generate new information. A number
of interesting examples were presented including multi-instrument data sets focused on precipitation to
particle size and mapping fast processes onto slow processes. This multi-sensor approach generates new
data sets and new science, which provides an in-depth integrated view of the Earth System. It was also
presented that the A-Train data sets are free and open, which enables augmented research work leading to
more science.
Discussion Highlights
• The issue of measuring over different time scales was addressed. Climate measurements require
sustainable measurements. Measurements from active instruments were identified as critical.
Passive instruments provide excellent indicative measurements but their results can be
ambiguous. Active instruments are much better at providing direct answers e.g. height, thickness.
•
Long-term active instrumentation beyond the EarthCARE mission was identified as critical.
•
The Earth System is a highly complex system with processes and phenomena occurring over a
wide range of spatial and temporal scales. Multi-satellite data sets show that these processes and
phenomena are all interlinked and fast processes project onto the longer scales. Examples
included bias errors in weather models errors and characterising cloud extent (which is an effect
of climate forcing). The key is to understand how the system evolves through sustained
measurement not just by providing intermittent measurements.
Key Points
• Complex systems require sustained measurement not just measurement snapshots of data.
• Active instruments are essential.
• Planning beyond EarthCARE is essential.
• Multiple measurements based on different physics measuring the same thing lead to
measurement validation and enables Earth system phenomena to be properly understood.
• The Earth System is a highly complex system with processes and phenomena occurring over a
wide range of spatial and temporal scales. Multi-satellite data sets show that these processes
and phenomena are all interlinked and fast processes project onto the longer scales. The key is
to understand how the system evolves through sustained measurement not just by providing
intermittent measurements.
5.1.2
Experience of GCOM-W1 Entering the A-Train
Presenter: Kiezo Nakakawa, JAXA
The GCOM series (Global Change Observation Mission) is a long-term programme comprising two kinds
of satellites: GCOM-W, GCOM-C. GCOM-W contributes to the observations of global water and energy
circulation. Its primary instrument is the Advanced Microwave Scanning Radiometer-2 (AMSR-2). The
GCOM-C satellite series will contribute to the surface and atmospheric measurements related to the
carbon cycle and radiation budget. Its primary instrument is the Second Generation Global Imager (IGLI)
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which comprises two radiometers: Visible and Near Infrared Radiometer (VNR) and Infrared Scanner
(IRS). The first GCOM-W1 satellite was launched in 2012 and GCOM-C is planned for launch in 2016.
Three generations of each type of satellites are planned over a ten-year timeframe. JAXA began GCOMW1 development in 2007.
In June 2008 NASA invited GCOM-W1 to the A- Train in the annual NASA/JAXA Earth Observation
Working Group Meeting. Measurement synergies were identified between the AMSR-2 and AQUAMODIS. It was requested by the JAXA science team that GCOM-W1 fly less than ten minutes away from
AQUA. The advantage of the GCOM-W1 mission flying in the A-Train was the increased science return
between the AMSR2 and the MODIS instrument particularly in the area of arctic sea ice motion. The
implication for GCOM-W1 was that the propellant budget had to be increased (around 50 kg due to
additional maneuvers), additional tasks related to the orbit development system also had to be added and
daily reporting of orbit details to NASA-GSFC had to be incorporated. The presentation detailed the
GCOM-W1 and its process of a member of the A-Train. Whilst on orbit AMSE2 (GCOM-W1) was
calibrated in a limited way using AQUA-AMSE-E. This improved AMSE2 data products. Future JAXA
scenarios are discussed in section 5.2.1.
Discussion Highlights
• The implication of the additional fuel was a critical design driver for GCOM-W1. This aspect
required detailed analysis to fully understand the implications.
Key Points:
The main lessons learned from GCOM-W1 included:
1) The ascent plan was written to prioritize the integrity of the A-train.
2) GCOM-W1 required much more fuel than originally planned (as a free flying satellite) for orbit
insertion and on orbit maneuvers within the constellation. This was a design driver.
3) The neighbourhood satellites near the target position should also be assessed for every new
satellite, even if the newly launched satellite does not intend to make a constellation with the
other satellites.
4) It is preferable that the orbit parameters of all operational satellites are shown in one website.
5) All space agencies should try to maximize the opportunities to perform the instrument cross
calibration when the observation orbit is agreed.
5.1.3
The Morning Train
Presenter: Mark Drinkwater, ESA-ESTEC, (Author: Kurt Thome, NASA-GSFC)
The Morning Train (M-Train/Morning-Constellation) has a 16-day repeat cycle with a 705 km altitude
and descending node. It comprised four satellites: Landsat-7 (Launched in April 1999), Terra (launched
in December 1999) comprising five sensors: ASTER, CERES, MISR, MODIS and MOPITT. EO-1 and SACC added in November 2000 (joint launch) and SAC-C, which was developed through cooperation between
NASA and CONAE. SAC-C is no longer in the constellation. EO-1 is now drifting (this was originally a oneyear technology validation mission with two instruments: ALI (push broom version of ETM+), Hyperion
(narrow swath hyperspectral). Landsat-5 and Landsat-8 (multispectral imagers from 30 to 60 m
resolution) can be considered to be in the M-Train due to the orbital similarities. Landsat-5 is no longer
operational. Landsat-8 is eight days out of phase with Morning-Train.
Statistically on a global scale there (in theory) are less clouds in the morning and therefore the Morning
Train focuses on a broad range of applications including land processes, land surface changes, energy
budget characterization and atmospheric retrievals. Multiple sensors flying along the same path, looking
at the same scene with the same solar geometry coupled to extensive validation efforts provided early
inter-calibration and validation data. The benefits of the M-Train are the resulting synergistic products. A
number of examples were presented e.g. combined MODIS, MISR and CERES data to support energy
budget characterization. The ability to perform data filling was another example e.g. ETM+ scan-line
corrector failure created gaps in Landsat-7 data. MODIS, ALI, and ASTER data provided the data
necessary to evaluate gap-filling approaches. This approach of having multiple sensors measuring along
the same path allowed for redundancy and gap filling for time series data products. Each year provides
new combinations of the sensor data for synergistic data products. Lessons learned related to calibration
and validation activities. It was also presented that a MODIS-type replacement in a morning local time is
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imperative (e.g., OLCI on Sentinel-3).
Discussion Highlights
• The issue of co-registration of multiple sensors flying in the train is a complex problem and
should not be overlooked. Issues such as differing sensor resolution and swath width must be
addressed including the problem of cloud movement and characterization.
• The issue of downlink was raised particularly related to closely flying high data rate sensors. This
is seen as a constraint with a number of solutions e.g. higher bandwidth downlink, GEO data
relay.
Key Points
• Multiple sensors flying along the same path, looking at the same scene with the same solar
geometry coupled to extensive validation efforts provide critical inter-calibration and validation
data.
• Co-registration of multiple sensors flying in the train is a complex problem and should not be
overlooked.
• The issue of downlink was raised particularly related to closely flying high data rate sensors.
This is seen as a constraint with a number of solutions e.g. higher bandwidth downlink, GEO
data relay
5.1.4
Experiences with Calipso and Future Opportunities
Presenter: Jacques Pelon, CRNS, (Dave Winker, NASA-LaRC)
Calipso comprises three instruments: Caliop (polarization lidar), Imaging Infrared Radiometer (IIR) and
a Wide Field Camera (WFC). Caliop has a 70 m footprint (small compared to most cloud scales). Caliop
provides direct measurements of cloud height. Calipso was designed to fly with Cloudsat and together the
satellites provide complementary measurements. Caliop, when used with MODIS data can provide
improved aerosol/cloud separation. Results from multi-satellite data product research were presented
including e.g. validation of cloud top heights measured by MODIS, comparison of atmospheric motion
vectors measured by MSG-SEVIRI.
The lessons learned included that nadir measurements are sufficient for studies using statistical
approaches or for reference. Formation flying enables synergies and allows for flexibility. Depolarization
is tremendously useful for e.g. improved cloud ice/water phase information (added value with IIR) and
improved aerosol typing is possible due to robust detection of dust and volcanic ash (added value with
IIR). Low-level broken clouds are uniquely detected by lidars in multi-layered systems. Aerosol type is
critical for atmospheric models (especially over/near clouds. Lidar and passive radiometry are sensitive to
different light-matter interactions and therefore lidars can be used to validate and constrain passive
retrievals (uncertainty reduction). Active measurements should be seen as an essential part of a cloudaerosol- precipitation climate observing system. Long-term measurements are required to identify,
understand, and characterize cloud-climate feedback and characterize key modes of climate variability.
Adding a simple backscatter lidar to provide support data for existing missions can be useful to establish
scene characteristics.
Key Points
• Active instruments such as lidars can be used to validate and constrain passive retrievals
• Formation flying enables synergies and allows flexibility.
• Long-term measurements are required to identify, understand, and characterize cloud-climate
feedback and characterize key modes of climate variability.
• Adding a simple backscatter lidar to provide support data for existing missions could be
invaluable to remove unwanted clutter in the actual measurement e.g. presence of thin cirrus
clouds.
5.1.5
TerraSAR-add-on for Digital Elevation Measurements
Presenter: Ulrich Steinbrecher, DLR
The TerraSAR-X-add-on for Digital Elevation Measurements (TanDEM-X) mission was designed to fly
with the TerraSAR-X (X-band SAR satellite) mission. The two satellites fly in a closely controlled double
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helix formation with typical distances of between 250 and 500 m. The TanDEM-X satellite is virtually a
re-build of TerraSAR-X with only minor modifications such as an additional cold gas propulsion system
for fine-tuning and an additional S-band receiver to receive TerraSAR-X status and GPS position
information. For bi-static and multi-static SAR satellites, both synchronization and calibration
considerations are critical. Mutual radiation was identified as a design constraint and as such TerraSAR-X
does not transmit on ascending orbits in the northern hemisphere and TanDEM-X does not transmit on
descending orbits in the southern hemisphere. The final TanDEM-X DEM delivery is planned to
commence early 2014. TanDEM-X is the forerunner for other mission concepts such as Tandem-L,
PICOSAR, and SIGNAL etc. Future scenarios set out by DLR are discussed in section 5.2.1.
Discussion Highlights
• For the pursuit mode the measurement repeat was in the order of 3 seconds, which translates to
around 20 km on ground. TanDEM-X uses varying baselines ranging from meters to kilometers
depending on the measurement required.
Key Points
• For bi-static and multi-static SAR both synchronization and calibration between the satellites is
critical.
• Mutual irradiation from each satellite was identified as a possible design constraint.
5.1.6
The Cosmo-SkyMed Constellation Mission
Presenter: Fabio Covello, ASI
The Cosmo-Skymed mission comprises four identical X-band SAR satellites flying in a constellation. The
first and second satellites were launched in 2007, the third in 2008 and the fourth in 2010. Two satellites
within the constellation fly in close proximity enabling the same area to be viewed with the same
geometric characteristics thus achieving a 1‐day interferometric acquisition mode. The system is
characterised by a fast response as it has four collection opportunities per day with right and left looking
access. The dual use system is able to support a number of applications including risk monitoring and
management, ocean and ice monitoring, coastal monitoring, forestry applications and urban planning.
The Abruzzo earthquake was provided as an example of the constellation capability. The response time for
this example was 12.5 hours from tasking to data product delivery. Other examples included: the
Louisiana oil spill, the Haiti earthquake, the Japanese tsunami and SAR images from the Costa Concordia
ship wreck off the coast of Italy. Cosmo-Skymed capabilities were presented including interferometry and
digital elevation model (DEM) generation. Examples of established mechanisms for international
cooperation were also presented.
Discussion Highlights
• There have been a number of bi-static configuration studies performed for Cosmo-SkyMed
(SABRINA), however, there are no plans at present to implement these study results.
• There are plans for a second-generation system and the requirements will essentially remain the
same as the existing system. The future plans for the Cosmo-Skymed second generation will be
presented in section 5.2.1.
• Cosmo-Skymed is used for maritime surveillance, which includes ship detection and recognition.
Key Points
• Multiple satellites are needed with left and right looking capabilities are needed for fast
response.
5.1.7
DMC Case Study - Benefits of Small Satellite Constellations
Presenter: Philip Davies, Surrey Satellites Technology Ltd (SSTL)
The Disaster Monitoring Constellation (DMC) has been developed over ten years and has a number of
international partners. There has been three generations of satellites (first generation: 32 m multispectral,
second generation: 22 m multi-spectral and third generation includes 2.5 multispectral. Future concepts
aim to provide resolutions of less than a metre. The DMC can provides a wide and if needed, a variable
swath width. The present DMC comprises 5 satellites, which can provide daily global coverage. The typical
image is 600 x 560 km. Due to limited on-board memory capability the system uses ‘windowing’ to target
areas of interest. The satellite discards raw data outside the predetermined areas of interest. DMC has
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provided annual maps of areas such as the Amazon rain forest. DMC is a member of the international
charter for space and major disasters. DMC has provided free data via the charter since 2005. At present,
a mission planning system selects areas of interest and imaging is performed as directed. The main areas
of future improvement include data storage, data downlink (X-band), provision of additional power
(bigger and more efficient solar arrays) and an improved network of ground stations.
Discussion Highlights
•
DMC performs vicarious calibration on an annual and monthly basis. DMC participates in the
annual calibration campaign at Railroad Valley, Nevada, USA. It also performs relative calibration
on a monthly basis using snow imagery during the day and imagery of the Pacific Ocean during
the night for the white and black reference signals.
• The effect of the free data policy of the Copernicus Sentinels, particularly Sentinel-2 data on the
DMC business case is unclear. It was highlighted that one possible option could be to optimise the
orbits of future DMC systems to take Copernicus Sentinels into account in order provide valuable
support to Copernicus.
• Possible developments to future DMC satellites could be the addition of SWIR. Thermal infrared
imaging would be more problematic but not impossible. This would be customer driven.
• SSTL are concerned that the provision of free Copernicus data to commercial users may enable
non EU companies to offer services back to the EU using data which has been paid for by the
European tax payer.
• The DMC data policy is at the individual owners discretion. DMC does not have a global data
policy.
Key Points
• DMC is an international collaboration. Each nation owns its own satellite. DMCii (sister
company to SSTL) centrally run the constellation.
• Low unit costs make the constellation viable.
• Constellations drastically improve the temporal resolution. Daily global coverage is easily
achieved with 5 satellites. This is critical for many applications.
• Constellations must be robust and should follow a systematic replenishment strategy.
5.2
5.2.1
Session 2: Future Landscape 2020 and Beyond
ESA Earth Explorer Programme
Presenter: Mark Drinkwater, ESA-ESTEC
The ESA Earth Explorer missions were presented in the context of ESA’s Earth Observation Envelope
Programme. This programme is science driven and peer-reviewed Earth Explorer proposals are typically
submitted in response to ESA Calls. Proposals respond to specific Earth science challenges for:
Atmosphere, Biosphere, Hydrosphere, Cryosphere and the Earth’s interior, as set out in ESA’s Earth
Science Strategy document [AD 1]. Proposals can lead to technology demonstrators, Earth Explorer Core
missions (typically larger missions with a three-stage procurement cycle (Phase 0, Phase A/B1, Phase
C/D/E), and Earth Explorer Opportunity missions (typically smaller but more technologically mature
missions with a two-stage development cycle (Phase A/B1, Phase C/D/E).
ESA Earth Explorer Missions
Gravity field and steady-state Ocean Circulation Explorer
(GOCE)
Soil Moisture and Ocean Salinity (SMOS)
CryoSat-2
Swarm
ADM-Aeolus
Clouds and Radiation Explorer (EarthCARE)
Biomass
Earth Explorer 8 Candidate Missions:
Ø Florescence Explorer (FLEX) planned to fly in
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Status
Mission Complete (De-orbited in late 2013)
Mission extension foreseen until 2017 (if approved)
Mission extension foreseen until 2017 (if approved)
Mission launched 2013
Launch planned 2015
Launch planned 2016
Launch planned 2020
Launch planned for one mission post 2020
tandem with Sentinel-3
Ø CarbonSat
Earth Explorer 9 - call for proposals
2014
Table 3 ESA Earth Explorer Missions (Past, Present and Future)
Key Points
• Scientific synergies are gained from overlap between Earth Explorer missions and Sentinels
• Many new potential opportunities exist by exploiting new combinations of measurements to
solve specific scientific problems
• Future Earth Explorer calls may feature opportunities to conceive missions in conjunction with
the Sentinels.
• In the 2020 time frame, a number of missions will be in-orbit: Biomass (P-band), CosmoSkymed2 (X-band), SAOCOM (L-band) and Sentinel-1A/B (C-band). These missions,
collectively, will operate all the frequencies envisaged in the original NASA multi-frequency EOS
SAR concept of the early 90’s.
5.2.2
Overview of Copernicus and its Evolution
Presenter: Antonio Ciccolella, ESA-ESRIN
Copernicus, previously known as GMES (Global Monitoring for Environment and Security), is the
European Programme for the establishment of a European operational capacity for Earth Observation.
Copernicus comprises a set of systems, which collect data from multiple sources: Earth observation
satellites and in situ sensors such as ground stations, airborne and sea-borne sensors. The Copernicus
services address six thematic areas: land, marine, atmosphere, climate change, emergency management
and security. They support a wide range of applications, including environment protection, management
of urban areas, regional and local planning, agriculture, forestry, fisheries, health, transport, climate
change, sustainable development, civil protection and tourism. The dedicated space segment for
Copernicus comprises the Sentinels satellite series (Sentinel-1, -2, -3, -4, -5 and -5 Precursor and JasonCS) together with third party contributing missions e.g. missions operated by national agencies,
commercial entities and Eumetsat operated missions.
The driving principles of Copernicus include: continuity, observation frequency and evolution. The
evolution of the Copernicus space component is based on user needs, characterized by the demand for
new services, products, new observations and technology improvements. The aim is to have a stable space
segment baseline for a period of around 15-20 years per satellite generation. For Sentinel-1, -2 and -3 will
comprise two satellites (A and B) to be operated simultaneously. The launches of the Sentinel -1, -2 and -3
‘B’ satellites are planned for launch around 18 months after the ‘A-unit’ satellites are launched.
Corresponding ‘C’ and ‘D’ satellites are also planned.
Key Points
• Copernicus represents a stable long-term programme for Earth Observation into 2030s.
• The driving principles of Copernicus include: continuity, observation frequency and evolution.
• The dedicated space segment for Copernicus comprises the Sentinels satellite series (Sentinel-1,
-2, -3, -4, -5 and -5 Precursor and Jason-CS) together with third party contributing missions e.g.
missions operated by national agencies, commercial entities and Eumetsat operated missions.
• It offers the possibility for international cooperation.
• It is a stimulus to introduce innovation and to foster developments of future space systems, as
well as systems of systems.
• It leads naturally to consider constellations and formations of missions, in a wide variety of
architectures, ensuring enhanced and expanded long term data streams
5.2.3
Copernicus Sentinel-1
Presenter: Malcolm Davidson, ESA-ESTEC
Sentinel-1 is a C-band synthetic aperture radar system based on heritage from missions such as ERS and
ENVISAT. It will provide all weather, day and night radar imagery for land and ocean services. The first
Sentinel-1 satellite is planned for launch in Q2 2014 and the second (Sentinel-1B) is planned for launch 18
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months later. Sentinel-1 has a design life of 7.25 years with consumables for 12 years. Sentinels are fitted
with an Optical Communication Payload (OCP) for data transfer via laser link with the GEO European
Data Relay Satellite (EDRS). S-1 will measure in four modes characterised by different resolutions and
coverage. The duty cycle of S-1 in any mode is 25 minutes per orbit per satellite. In wave mode the duty
cycle is planned to be 74 minutes per orbit per satellite. The main mode of operation is planned to be the
interferometric wide swath (IWS) mode over land. Sentinel-1 will be operated continuously over the ocean
in wave mode (VV).
Key Points:
• Sentinel-1A and Sentinel-1B are identical C-band SAR satellites. Sentinels 1C and -1D are in the
ESA planning.
• Long-term guaranteed data source and global coverage benefits applications requiring longterm consistent time series,
• Open data policy for science users
• Frequent revisit benefits development of new applications monitoring dynamic events
• High radiometric image quality through TOPS scan mode
• Interferometry for land applications
• Conflict-free pre-programmed satellite operations based on a main mode of operation leading
to consistent image data stacks.
5.2.4
Copernicus Sentinel-2
Presenter: Klaus Scipal, ESA-ESTEC
Sentinel-2 will provide high-resolution optical imagery for land services. It will provide imagery of e.g.
vegetation, soil and water cover, inland waterways and coastal areas. Sentinel-2 will also deliver
information for emergency services. The first Sentinel-2 satellite is planned for launch in 2014. Sentinel-2
comprises two satellites (Sentinel-2A and -2B). Sentinel-2A is planned for launch Q1 2015 and -2B twelve
months later. Sentinel-1 has a design life of 7.25 years with consumables for 12 years. The Sentinel-2
payload is a filter based optical push broom imager with 13 spectral bands: 10 VNIR bands, 3 SWIR bands
and measures across three spatial resolutions: 10, 20, 60 m. Sentinel-2 will have a 5% radiometric
accuracy achieved with a combination of absolute calibration with sun diffuser, dark calibration over
ocean at night and vicarious calibration. Sentinel-2 has a revisit of 5 days (with two satellites).
Discussion Highlights
Potential additions to Sentinel-2 could be:
• Medium to high-resolution thermal infrared, multi-band radiometer to measure both emissivity
and LST.
• Additional bands in the medium to short wave infrared band with spatial resolution of less than
250 m for fire monitoring.
• Appropriate thermal channels and high spatial resolution to target active lava flows and
potentially detect SO2 in eruptive plumes for volcano monitoring.
• A BRDF instrument measuring at a range of angles.
• A lidar instrument to characterize vertical vegetation structure.
Key Points:
• Sentinel-2A and Sentinel-2B are identical optical satellites. Sentinels 2C and -2D are in ESA
planning.
• Long-term guaranteed data source and global coverage benefits applications requiring long-term
consistent time series,
• Open data policy for science users
• Frequent revisit benefits development of new applications monitoring dynamic events.
• Potential Convoy opportunities have been identified for Sentinel-2
5.2.5
Copernicus Sentinel-3
Presenter: Craig Donlon, ESA-ESTEC
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Sentinel-3 will provide high-accuracy optical, radar and altimetry data for marine and land services. It
will measure variables such as sea-surface topography, sea- and land-surface temperature, ocean colour
and land colour with high-end accuracy and reliability. The first Sentinel-3 satellite is planned for launch
in 2014 with routine operations shared between ESA and EUMETSAT. Sentinel-3 comprises three
primary instruments: the Ocean and Land Colour Instrument (OLCI), the Sea and Land Surface
Temperature Radiometer (SLSTR) and a dual frequency altimetry suite. The OLCI will measure from
400-1020 nm across 21 channels. The OLCI has a broad 1270 km swath. The SLSTR instrument measures
from 0.555 nm to 10.96 nm. The spatial resolution ranges from 500 m to 1 km (sample dependent). To
enable a wider swath, SLSTR uses two scan systems (nadir and oblique). A flip mirror is used to select
which optical path is directed towards the detectors. The nadir swath has a westerly offset to completely
overlap the OLCI swath. One VIS channel (865 nm) is used for co-registration with OLCI swath.
Sentinel-3 also has a multi-frequency (Ku-band and C-band) altimeter supported by a radiometer, laser
light reflector (LRR), GPS and DORIS. The altimeter will operate in high-resolution SAR mode and lowresolution mode. Sentinel-3 comprises two satellites (Sentinel-3A and -3B). Sentinel-3A is planned for
launch Q4 2014 and -2B is planned for launch at least 24 months later (TBC). Sentinel-3 has a design life
of 7.5 years with consumables for 12 years.
Key Points:
• Sentinel-3A and Sentinel-3B are identical satellites. Sentinels 3C and -3D are in ESA planning.
• Sentinel-3 is a multi-instrument platform comprising three primary instruments: the Ocean
and Land Colour Instrument (OLCI), the Sea and Land Surface Temperature Radiometer
(SLSTR) and a dual frequency (Ku/C-band) altimetry suite. The altimeter will operate in SAR
mode over the whole orbit.
• Long-term guaranteed data source and global coverage benefits applications requiring longterm consistent time series,
• Open data policy for science users
• Frequent revisit benefits development of new applications monitoring dynamic events.
• Potential Convoy opportunities have been identified for Sentinel-3
5.2.6
Copernicus Sentinels for Atmospheric Applications
Presenter: Paul Ingmann, ESA-ESTEC
Sentinel-4 will provide data for atmospheric composition monitoring. Sentinel-4 will be a payload
embarked on Meteosat Third Generation (MTG), and this is scheduled for launch around 2020. Sentinel4 will be operated by EUMETSAT. Sentinel-5 will also be dedicated to atmospheric composition
monitoring. Sentinel-5 will be a payload embarked on a MetOp Second Generation satellite (MetOp-SG)
and it is planned for launch in 2020. Sentinel-5 will also be operated by EUMETSAT. Sentinel-5 Precursor
is also planned for launch in 2015 to fill the data gaps before the launch of Sentinel-5 (see Session 3).
Key Points:
• Sentinel-4 will be a payload on Meteosat Third Generation (MTG) in geo-stationary orbit
(GEO).
• Sentinel-5 will be a payload on MetOp-SG in Low Earth Orbit (LEO).
• Sentinel-5 Precursor is a free flying satellite originally planned to fill the gap between the EOL
of Envisat and the BOL of Sentinel-5.
5.2.1
Overview of EUMETSAT Missions and Applications
Presenter: Johannes Schmetz, EUMETSAT
An overview of EUMETSAT missions was provided which included Meteosat, MetOp, Jason and Jason-CS
satellite series. It was highlighted that EUMETSAT Satellite Programmes contribute to global
constellations providing service continuity and service provision augmentation based on new
requirements and the evolution of new technological capabilities. The first Meteosat satellite was
launched in 1977. The first Meteosat Second Generation (MSG) satellite was launched in 2002. MSG is
able to provide a very rapid revisit: 15 minutes, 5 minutes and an experimental measurement mode able
to perform data capture measurements with a 2.5 minutes repeat cycle. Meteosat application examples
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(present and future) were provided and discussed. The Meteosat third generation (MTG) is planned for
launch round 2018 and shall comprise two GEO satellites: imager, sounder. MTG shall provide five
missions in total:
• Full disk scan (optical and thermal infrared) with a revisit of 10 minutes, with 16 channels
between 1 to 2 km spatial resolution.
• Rapid disk and local scale scan (optical and thermal infrared) with a revisit of 2.5 minutes with 4
channels between 0.5 to 1 km spatial resolution. Local scales measured 0.25 of full disk.
• Full disk infrared sounding with a repeat cycle of 15-30 minutes (depending on the mode) and
hyperspectral sounding shall be performed in the mid to long wave infrared.
• A lightening imager shall provide detection and mapping of intra-cloud and cloud-ground
phenomena and finally an
• Ultraviolet-visible-near infrared (UVN) sounding (Sentinel-4) shall provide atmospheric
measurement.
Continuity of the EUMETSAT Polar System Services is planned beyond 2020 with the provision of MetOp
Second Generation (MetOp-SG). This is known as EUMETSAT polar system second generation (EPS-SG).
This shall provide continuous long-term datasets in support of operational meteorological and
environmental forecasting and global climate monitoring. MetOp-SG shall be part of the
NOAA/EUMETSAT Joint Polar System Service (JPSS) in the morning (9:30 am) orbit. MetOp-SG shall
comprise two satellites in polar orbit. MetOp-SG will fulfil the European contribution to the GOS
regarding the space-based polar orbit observations. MetOp-SG will rely on international cooperation for
the satellite development and on national contributions for key instruments: space segment development
(ESA), development IASI-NG (CNES) and the development of METimage (DLR). Other instruments
include microwave sounders, microwave imagers, multi-spectral imagers (Sentinel-5), a scatterometer
and radio occultation instruments.
Discussion Highlights
• There are measurement overlaps between IASI and Sentinel measurements. IASI was originally
designed to provide temperature and humidity measurements for weather forecasting. Sentinel-5
is based on GOME heritage. Both instruments provide complementary information.
• Operational monitoring and long-term science are converging.
Key Points
• Early coordination with WMO ensured early cooperation and requirement analysis
• A constellation approach has enabled a common science basis.
• For these systems radiometric and spectral accuracy was prioritized over spatial accuracy.
• IASI-NG and Sentinel-5 provide complementary information. Together they provide information
about total column.
5.2.1
5.2.1.1
National Agencies Future Scenarios
The German Aerospace Center (DLR)
Presenter: Peter Schaadt, DLR
DLR provided an overview of the German Earth Observation Programme and Opportunities of
Formations. In-orbit experience includes GRACE (since 2002), Rapid-Eye (since 2008) and TanDEM-X
(since 2010). Planned formations include GRACE Follow On mission comprising two satellites and it is an
international cooperation between Germany and USA. Phase C/D/E is scheduled to commence in Q1 2014
with a tentative launch in 2017. It is a near identical development in terms of hardware and organizational
set-up with some advancement including a laser ranging interferometer and a star camera with a three
head capability. Planned missions include TanDEM-L, which is a bi-static SAR mission (L-band) and an
international cooperation between Germany and Japan. WorldSAR was presented which is a concept in
the planning which comprises 3-5 satellites providing a global and near real time capability. Suggested
WorldSAR assets include: TerraSAR-X, TanDEM-X, and PAZ etc. The hyperspectral optical imager
(EnMap) was presented and possible synergy opportunities with Sentinel-2/ Landsat and ALSO-2 were
discussed. Enmap is planned for launch in 2017. The French-German Climate mission (MERLIN) concept
was also presented and possible synergies with GOSAT, OCO and Sentinel-5 Precursor were highlighted.
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MERLIN is in Phase B and is planned for launch in 2017. Other presented bi-static SAR concepts included
PICOSAR (see section 5.7.4) and the SAR for Ice and Glacier aNd GlobAL dynamics (SIGNAL).
5.2.1.2
The Japanese Space Agency (JAXA)
Presenter: Haruhisa Shimoda, JAXA
JAXA have numerous national and international cooperation missions scheduled for launch in the
coming decade: GPM (2014), ALOS-2 (2014), EarthCARE (2016), GCOM-C1 (2016), GOSAT (2018).
Other concepts being studied include: ALOS-2 follow on mission and -W2 mission. Possible synergies are
presently being explored between the Second Generation Global Imager (SGLI) instrument on GCOM-C1
and Sentinel-3.
Discussion Highlights
• The descending node crossing times of Sentinel-3 were driven by the strong variability in the
diurnal cycle of sea surface temperature and the fact that long term time series data sets existed
from instruments such as the ATSR. It was decided to continue the node crossing time so not to
compromise the sea surface temperature measurements.
• JAXA are presently evaluating possible options concerning GCOM-C1 and Sentinel-3.
• The ALOS mission shall provide Doppler centroid information.
5.2.1.3
The Italian Space Agency (ASI)
Presenter: Fabio Covello, ASI
The Cosmo-Skymed Second Generation (CSG) is the follow‐on mission to Cosmo Skymed (CSK). The CSK
constellation has been fully operational since 2011. The first CSG satellite is planned for launch in mid
2016 and the second 12 months later. The aim is for CSG to provide operational continuity until at least
2024. The main CSG enhancements include: full polarimetric capability (stripmap), more robust planning
algorithm, and improved satellite agility. The spatial resolution and geo-location will be 1 m (spotlight)
and improved by a factor of two in scanSAR mode. The operational profiles will also be improved from
450 products/day/satellite to 520 products/day/satellite. The duty cycle of CSG will be improved by
around 30 % per satellite.
CSK and soon to be CSG will be a pillar of the Multinational Space-based Imaging System for
Surveillance, Reconnaissance and Observation (MUSIS) system. This is an international program
including six nations (France, Italy, Belgium, Germany, Greece, and Spain). MUSIS enables these six
countries to share imagery from various dual use/military satellites through a common, generic user
ground segment (UGS) according to agreed rules.
5.2.2
WMO Vision for the Space-based Observing System in the 2020’s
Presenter: Jerome Lefeuille, World Meteorological Organization (WMO)
The WMO Integrated Global Observing System (WIGOS) aims to integrate the space and surface based
observing systems coordinated by WMO. It includes e.g. World Weather Watch (supporting weather
forecasting), Global Atmospheric Watch (atmospheric composition, climate & air quality), WHYCOS
(hydrology), Future Global Cryosphere Watch and the WMO contribution to GCOS (climate). It is part of
the Rolling Review of Requirements for Global Observing Systems.
The WMO Commission for Basic Systems (CBS) and the Executive Council adopted the WIGOS vision in
2009. The next update is planned in 2016 (typically updates are every 8 years).
The vision of global observing systems for 2025 includes measuring variables such as e.g.:
• Cloud properties (amount, type, top temperature, height, phase, etc)
• Atmospheric temperature and humidity (3D)
• Wind (3D and at ocean surface)
• Precipitation intensity
• Thunderstorms
• Aerosols (volcanic ash, dust,)
• Atmospheric composition (ozone, other GHG, etc)
• Radiation budget components
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• Ocean surface (sea level, ocean colour, sea ice, sea state, surface temperature)
• Land surface (temp, vegetation, fire, floods, moisture, topography, snow & ice, albedo)
A vision for 2025 for future observations was presented which included a geostationary constellation
component comprising VIS/IR imagery, IR hyperspectral, lightning imagers and a core sun synchronous
constellation component across three local times (early morning, mid morning and afternoon)
comprising: VIS/IR imagery, IR hyperspectral, MW sounders etc. It is likely that Chinese colleagues will
launch FY-3E into an early morning observations in 2016.
Other constellations presented included e.g. microwave imagery, altimetry, scatterometry, radiooccultation, global precipitation (GPM configuration). Other aspects addressed include: atmospheric
composition, Earth radiation budget assessment and multi-directional viewing IR imagery.
Cosmic-1 and 2 radio-occultation missions were presented which comprise six satellites in polar and
elliptical orbits (planned to be 8 satellites in 2018).
A mission using highly elliptical orbits to observe the Artic was also presented. This highly elliptical orbit
mission is included in the present WMO vision as a demonstration mission rather than an operational
mission. Future high inclination missions, which were highlighted include: the Canadian Polar
Communication and Weather (PCW) mission and the Russian ‘Artica’ mission.
Inter-calibration is critical to ensure data consistency over long time series particularly for climate
monitoring. Good calibration also enables effective data merging from various sources and it allows data
gaps to bridged. It was highlighted that one instrument acting as a reference calibrator can be used to
enhance the return of other instruments.
The Observing System Capabilities Analysis and Review (OSCAR) activities were also highlighted. It
includes three components: repository of observation requirements, a space-based missions inventory
and surface-based observations (which is still under construction). OSCAR replaces the former WMO /
CEOS database and the WMO Dossier on Space-based GOS (which is no longer maintained).
Key Points
• WIGOS focuses on the integration of space and surface based observations, which includes
weather forecasting, atmospheric composition, air quality, hydrology and climate observations.
• Inter-calibration is critical to ensure: data consistency over long time series, effective data
merging from various sources, to bridge data gaps.
• It was highlighted that one instrument acting as a reference calibrator can be used to enhance
the return of other instruments.
• Combined GEO and LEO missions providing observations (at different local times) are needed.
5.3
5.3.1
Session 3: ESA Convoy Missions and Mission Candidates
The FLEX Mission: Benefits and constraints of flying with Sentinel-3
Presenter: Stefan Kraft, ESA-ESTEC
The Florescence Explorer (FLEX) is an Earth Explorer 8 candidate mission. It is designed to fly in convoy
with Sentinel-3. The science objectives include the global mapping of vegetation fluorescence, estimation
of global photosynthetic activity, vegetation health status / stress identification and anthropogenic
impacts associated to land use changes etc.
The FLEX payload is a hyperspectral FLuORescence Imaging Spectrometer (FLORIS). The spectral bands
range from 500 to 780 nm. The FLEX mission shall utilise Sentinel-3 auxiliary data to improve
atmospheric corrections, temperature, aerosol context and cloud information. The temporal resolution
between FLEX and Sentinel-3 is designed to be between 6 and 15 seconds.
FLEX was originally a submitted proposal for the seventh Earth Explorer cycle (EE7). The concept was
redesigned as a convoy with Sentinel-3 for EE8 and resubmitted. The benefits of the convoy include a
reduced payload complement and an associated three fold cost reduction. The synergies with Sentinel-3
include cross-calibration, combined operation, use of data products. The florescence can also be used to
improve Sentinel-3 data products. The convoy design has meant that FLEX now has to fly at the Sentinel3 altitude (around 200 km higher than original concept). Other aspects being assessed include:
propellant, interference, downlink options and Sentinel-3 programmatics.
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Key Points
• Good example of new mission optimization benefiting from data provided by another mission.
• FLEX shall fly between 6 and 15 seconds in front of Sentinel-3.
• The benefits of the convoy include a reduced payload complement (based on the original standalone concept), a three-fold cost reduction and added synergies with Sentinel-3.
• Convoy implications include: propellant, interference, downlink options and Sentinel-3 (anchor
satellite) programmatics and associated in-orbit manoeuvres
5.3.2
End-to-End Mission Performance Simulators for EO Convoy Missions:
Application to FLEX/Sentinel-3 Mission
Presenter: Jorge Vicent, University of Valencia
An End-to-End Mission Performance Simulator is a set of algorithms whose aim is to reproduce expected
mission planning, assess mission performance, support the consolidated technical requirements and
provide an environment to analyze developed Level-2 retrieval schemes. The FLEX simulator follows an
E2ES reference architecture developed under another ESA contract. The FLEX simulator has three
different instrument and Level-1 processing chains and the first results were presented.
Discussion Highlights
• Sentinel-3 will have dedicated retrievals of parameters such as e.g. aerosols with know error
budgets. The FLEX simulator will take this simulated Sentinel-3 data as input for comparison and
also use FLORIS data to provide synergistic data products and to aim to provide improved
atmospheric correction.
• ECMWF data is used as input in the scene generator. Implemented models within the simulator
include a simplified cloud model (bright objects and shadows) and a radiative transfer surface
and atmospheric model.
Key Points
• The interface design between modules is critical.
• Simulated Sentinel-3 data can be used for reference and comparison.
• The application of the generic E2ES Reference Architecture is applicable to multi-satellite
missions.
5.3.3
ESA’s Sentinel-5 Precursor: Mission & Operations Concept
Presenter: Herbert Nett, ESA-ESTEC
Sentinel-5 Precursor (S5P) shall be the first spacecraft in series of atmospheric observing systems within
the Copernicus programme. S5P is scheduled for launch in 2015 and overlap with Sentinel-5 is foreseen.
The aim of S5P is to monitor global atmospheric constituents such as O3, NO2, SO2, CO, CH4, HCHO,
clouds & aerosols in the Troposphere and lower Stratosphere. It shall provide enhanced radiometric
sensitivity and spatial resolution (typically 7 x 7 km2) enabling sampling of small- scale variability
specifically in the lower troposphere. S5P will have a near real time service for a subset of Level 2 products
(within three hours).
The S5P comprises TROPospheric Monitoring Instrument (TROPOMI), which is a set of UV-VIS-NIR
spectrometers developed as national contribution by The Netherlands. The SWIR module is being
developed under ESA contract. The platform Critical Design Review (CDR) is planned for Summer 2014.
Instrument delivery is planned for Q2 2014.
It is planned that S5P will follow the ground track of Suomi-NPP. This is driven by the TROPOMI SWIR
channel L2 processing (for CH4 measurement, which relies upon accurate, high-resolution cloud mask
data). The separation between S5P and Suomi-NPP is planned to be of the order of 5 min +/- 5 min).
Orbit maintenance for S5P must be coordinated with Suomi-NPP (along-track separation most critical.
Other possible synergies highlighted were e.g. the use of VIIRS data for routine CH4 processing.
Discussion Highlights
• Suomi-NPP has a scheduled EOL of 2018. Sentinel-5 is scheduled for launch in 2020/2021. On
paper, there is a three-year gap where cloud image data would be needed. One possible spacecraft
candidate to supply this data could be JPSS. However, it is unclear to ESA if the JPSS orbit has
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been fixed. If the JPSS orbit differs significantly from its original 13:30 local time then its added
value to the Sentinel-5 Precursor mission would be minimum and other options would have to be
explored.
The temporal resolution between Suomi-NPP and S5P is critical e.g. an across track separation
can lead to a parallax error etc.
There is a need to coordinate S5P and Suomi-NPP maneuvers.
All data products are to be near time except those related to CO, CH4, cloud imager and one of the
aerosol products. Processing time and on board data storage are the main limitations. For CH4
retrieval, the auxiliary cloud products are required from the VIIRS instrument.
Key Points
• Sentinel-5 Precursor (S5P) shall be the first spacecraft in series of atmospheric observing systems
within the Copernicus programme.
• It is planned that S5P will follow the ground track of Suomi-NPP (5 min +/- 5 min). This is driven
by the TROPOMI SWIR channel Level 2 processing (for CH4 measurement, which relies upon
accurate, high-resolution cloud mask data).
• Following Suomi-NPP EOL other options to provide cloud imagery to S5P have been investigated.
One possible solution is JPSS. However, the added value of JPSS to S5P depends on the final orbit
choice of JPSS, which is unclear at present.
• All data products will be available in near real time except those related to CO, CH4, cloud
imagery and one of the aerosol products.
5.4
5.4.1
Session 4: Technological Challenges
Constellation Lessons-Learned from the Cloudsat Experience
Presenter: Deborah Vane, NASA-JPL
Lessons learned from the 7 years of the Cloudsat mission experience were presented. The history of the
Cloudsat and Calipso missions was presented. In the beginning NASA-JPL and NASA-Langley developed
a concept (driven by science) comprising a cloud lidar instrument and a cloud radar instrument flying
together on one platform. Subsequently, NASA-HQ opened an announcement of opportunity (AO) for an
Earth System Science Pathfinder mission with a cost cap of 90 million dollars. This cap was too small to
embark two instruments on one platform. It was decided to split the NASA-Langley and NASA-JPL
instrument teams into two competing teams. Both teams were eventually selected together, which lead to
Cloudsat and Calipso flying together in the A-Train.
Key Points
• Constellations require agency vision and support
Ø NASA-HQ selected both proposals (Cloudsat and Calipso) to fly together and asked both
teams to investigate formation flying.
• The constellation mind-set
Ø Flying in a constellation requires a shift in thinking from mission level to constellation level.
Acknowledgement that certain mission activities may impact other missions e.g. data sets,
orbit, downlink etc. These considerations need to be identified, communicated, managed
and resolved on a constellation level.
• The impact on satellite design of flying in a constellation
Ø Addition resources may be required for a satellite flying in constellation compared to flying
alone e.g. fuel gauge, transponder, additional fuel and additional mass memory.
• The compromise of constellation level science and orbit choice
Ø The choice of flying Cloudsat and Calipso at 705 km was a compromise as active instruments
usually fly much lower. The science benefits of flying with e.g. MODIS were seen as a great
opportunity.
Ø The orbit choice is critical. Constellation participation depends upon the attractiveness of
the orbit.
• The virtual spacecraft
Ø For constellation level science, Cloudsat and Calipso are considered to be one virtual
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spacecraft. Both mission teams devised methodologies for this and before the Cloudsat
battery anomaly in 2011 both footprints completely overlapped for 90 % of the orbit.
Understanding your spacecraft – spacecraft modes
Ø When flying closely with other spacecraft it is critical that the different propulsive modes are
known in detail e.g. Cloudsat has a propulsive safe mode, which activated after the battery
anomaly occurred. This had to be extensively studied by the Calipso team to understand the
implications.
Mission flexibility
Ø Sun glint (from clouds and ice surfaces etc.) was an issue for both Cloudsat and Calipso. The
two spacecraft could be re-aligned independently on-orbit as they were on different
platforms. This lesson has been incorporated into the EarthCARE mission design.
Constellation level management, procedures and processes
Ø NASA-GSFC provides manpower to coordinate the A-Train Mission Operations Working
Group (MOWG), which comprises representatives from all the A-Train missions. This group
is responsible for setting up all the agreements between the mission teams and it meets
every six months. The MOWG manages mission team expectations and provides a forum for
information exchange.
Ø The A-Train mission teams adhere to strict written processes and procedures. This is critical
to ensure smooth running of the constellation e.g. entering, maintaining, changing and
exiting the A-Train.
Constellation level data sets
Ø Multi-satellite data sets are complex. An infrastructure is needed to support multi-satellite
data products e.g. the explicit responsibilities for data set combination and fusion, coregistration and combination, research funding for working on multi-satellite data sets.
Ø NASA-GSFC operates the A-Train Data Depot.
5.4.2
End of Mission Planning Challenges for a Satellite in Constellation
Presenter: Ronald Boain, NASA-JPL, (Barbra Braun, Aerospace Cooperation)
All A-Train satellites operate within their own control box, which involved the missions flying within a
predetermined three-dimensional box centred on the spacecraft as it flies along the orbit. This is driven
primarily by observation simultaneity, congruence of observation (to allow for Earth rotation) and safety
(impact mitigation). Cloudsat and Calipso in particular are coordinated so that they had less than a 15
second temporal separation at the equator to ensure radar and lidar footprint overlap (prior to the battery
anomaly in 2011).
Key points:
• A-Train operates a control box methodology, which involved the missions flying within a
predetermined three-dimensional box centred on the spacecraft as it flies along the orbit.
• The control box parameters must be derived from science requirements.
• The spacecraft must perform small manoeuvres with fine granularity (around 0.5 cm/s).
• An ability to perform retro velocity manoeuvres is critical.
• High fidelity orbit propagators with detailed atmospheric density models were not needed for
Cloudsat. The mission used a simple parabolic motion model and past data to predict future
motion. This was adequate to keep Cloudsat within its predetermined control box.
• Satellites with different ballistic coefficients will need more manoeuvres to stay in formation.
• Close coordination between satellites operation teams is important.
5.4.3
Similarities and Differences between the A-Train and the Proposed J-Train
(JPSS)
Presenter: Mark Vincent, Raytheon (via WEBEX)
The safety of constellation flying is driven by the fact that the control boxes in which the individual
satellites fly are separated by buffers, which results in the boxes never intersecting with each other. One
lesson learned is that this should be considered at the two points where any individual satellite’s orbit
crosses the plane of another satellite. For the A-Train satellites the two crossing points are near the north
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and south poles. The concept of the ‘Triad’ was presented which comprises: mean local time, ground track
and the phasing. Only two of the three parameters are independent. The concept of the snapshot
diagrams were presented which is one method flight dynamists use to visualise the A-Train orbit positions
of the various missions relative to the Aqua satellite. A number of lessons learned were presented. Firstly,
an agreement of the reference ground track definition is critical. Secondly, the definition of the phasing at
the poles is also important to prevent conjunctions. Lastly, one concept currently being refined for the
satellites at 705 km is the concept of an “envelope”, which is relevant for near-frozen orbits to ensure that
satellites does not collide with each other.
The orbits of A-Train and JPSS were compared. The lower 705 km orbit is characterized by a far greater
atmospheric density (around 3 times more dense than at 824 km). Drag Make-Up (DMU) maneuvers are
small compared to Inclination Adjustment Maneuvers (IAM) at 705 km and the effect will be even smaller
at 824 km. Both DMU and IAM cause relative along-track motion and so at the higher altitude this is
more critical. Pointing errors during IAM, at 824 km will not be trivial. Similarly Risk Mitigation
Maneuvers will be large compared to DMU maneuvers.
Key Points
• The A-Train uses pre-defined control boxes with buffers to maintain the orbit safety of the
constellation.
• Visualization methodologies for satellite constellations, control boxes, temporal separations etc.
are very important.
• An agreement of the reference ground track definition is required
•
The definition of the phasing at the poles is also important to prevent conjunctions.
•
Comparing A-Train (705 km) and JPSS (824 km) orbit
5.4.1
o
Atmospheric density much greater at lower altitude.
o
Drag Make-Up (DMU) maneuvers are small compared to Inclination Adjustment
Maneuvers (IAM) at 705 km (even smaller at 824 km).
o
Both DMU and IAM cause relative along-track motion and so at the higher altitude this is
more critical.
o
Pointing errors during IAM and Risk Mitigation Maneuvers, at 824 km will not be trivial.
The Jason-1 EOL Case Study
Presenter: Christophe Marechal, CNES
Jason-1 was an ocean topography mission flying at a 1336km altitude. It was a NASA-JPL/CNES joint
mission. In 2011, several key components on the spacecraft had become single-string meaning that the
permanent loss of any one of these key components would end the mission and could leave Jason-1 adrift.
In 2010 the science sub-group recommended that Jason-1 remain in its orbit and that alternative
scenarios be studied. By 2012, it was agreed to commence fuel depletion and an extension plan for Jason1 was defined. The orbit change was completed in May 2012. Jason-1 EOL occurred in July 2013. Jason-1
was properly decommissioned and the spacecraft did not pose a threat to current/future altimetry
mission (Jason-2, Jason-3, Jason-CS).
Discussion Highlights
• As Jason-1 is in a much high LEO orbit the 25-year deorbit rule is not applicable until it reaches a
lower altitude. A specific graveyard orbit for Jason-1 was defined to handle this risk.
• These lessons learned need to be taken up by the inter-agency operations group to define specific
codes of practice for these kinds of situations including a means to coordinate and communicate
information and actions.
Key Points
• Science drives the mission until the spacecraft health reaches a limit. There is a time when the
satellite needs to get out of the way. An alternative orbit can be defined before launch.
• Discussion between technicians and scientists were highlighted early to provide enough time for
common inter-agency procedures to be agreed and implemented.
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Early risk reduction activities were identified and performed (depletion)
EOL issues require codes of practice to be agreed at agency and inter-agency level including
means to coordinate and communication information and actions.
•
•
5.5
Session 5: EO Convoy Studies
The European Space Agency (ESA) is funding three exploratory activities (known as the EO-Convoy
studies). The aim of these studies is two fold: Firstly, to identify scientific and operational objectives and
needs which would benefit from additional in-orbit support. Secondly, to identify and develop a number
of cost-effective convoy concepts (comprising additional missions flying with European operational
satellites), which would meet these identified objectives and needs. Each EO-Convoy study is dedicated to
a specific theme:
• Study 1: Ocean and Ice applications
• Study 2: Land applications
• Study 3: Atmosphere applications
Each study is based on a user needs analysis and derived preliminary convoy mission concepts. Up to
three mission concepts per theme were then selected for further analysis. The gap analyses documents of
the three studies can be found on the workshop website [AD3], [AD 4] and [AD 5]. The analyses were
based on the ESA Science Strategy [AD 1] [AD 8].
5.5.1
ESA Convoy Definition:
A convoy configuration is defined as a single or multiple satellites flying closely behind or in front a
predefined anchor satellite e.g. Copernicus Sentinels, MetOp-SG etc. The temporal separation between
the satellites is in the order of seconds to minutes.
5.6
•
•
•
•
•
Overall ESA EO Convoy Studies Workshop Feedback
The Copernicus Sentinels is a constellation in itself and possible synergies should be exploited
The Sentinels do not fly in convoy with each other but further activities focused on synergetic use
of Sentinel data on a constellation level should be considered.
The convoy studies focused on extending scales of known parameters. It was discussed whether
to open out this analysis away from incremental deltas related to known parameters and move
towards broader measurement gaps which are needed to comprehensively understand the Earth
system e.g.:
o Characterising the interfaces and interactions between the various Earth system domains.
o Identifying and understanding the various flux exchanges and their impact on the Earth
System.
It was agreed that these more broad science deltas were needed and that constellations and
convoy configurations should be addressing these big questions. However, it was also highlighted
that parameter extension such as improved spatial resolution and the power of synergies should
not be underestimated to improve current capabilities. One example cited was the improvement
of surface winds over the ocean, which drives sea state and associated fluxes. Flying different
instruments together measuring at different resolutions in a synergetic way is a powerful
technique.
It was highlighted there needs to be there is a paradigm shift away from classical Earth science
divisions of e.g. ocean, ice, land and atmosphere etc. A wider cross crossing approach was needed
to include all the mechanisms and processes with the Earth system. Constellations and convoy
were natural candidates for this kind of approach. Future concepts should be cross cutting and
inclusive. The example given was to design constellations to understand a cycle e.g. water, carbon
etc.
The value of a constellation/convoy was seen in its ability to measure phenomena and processes
across all Earth System domains. The challenge is to define how to cross cut these classifications
and identify where the interactions occur e.g. gravity measurement, snowfall, freeze thaw cycles
etc. The Gravity field and Steady State Ocean Circulation Explorer (GOCE) mission was given as
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an example as one of its results was the measurement of ice mass change in Greenland.
Parameters and processes traditionally partitioned into separate categories should be considered
together.
It was also pointed out that missions addressing other domains might provide useful results even
if the viewing geometries are not optimum.
Measurements from active instruments were seen as critical to provide direct measurements and
to validate and calibrate retrievals obtained from passive instruments.
Operational satellites such as the Copernicus Sentinels, Landsat follow-on developments and
others are natural candidates to act as anchor points for future constellations. Any future
constellation should be designed to extract all possible synergies from the satellites in these
bigger programmes even if the concepts do not fly in convoy or constellation.
5.6.1
5.6.1.1
ESA EO Convoy Study - Ocean and Ice Applications
Identification of Measurement Gaps
Presenter: Helmut Rott, University of Innsbruck
Analysis performed by: Nansen Environmental and Remote Sensing Centre (N), University of Innsbruck
(A) and Polar Imaging Ltd (UK).
The following section provides a brief overview of the measurement gap analyses performed by the EO
Convoy Ocean and Ice Science team [AD 3]. For the purposes of this analysis the ocean and ice domain
was split into three sub-domains: ocean, sea-ice and land-ice.
The Ocean Domain
Table 4 Identified measurement gaps in ocean domain
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The Sea-Ice Domain
Table 5 Identified measurement gaps in the sea-ice domain
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The Land Ice Domain
Table 6 Identified gaps in land-ice domain measurement
5.6.1.2
Derivation of Convoy Concepts
Presenter: Nic Leveque, Astrium Ltd
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Analysis performed by: EADS Astrium. Based on the user needs analysis a number of convoy concepts
were identified. A non-exhaustive list can be seen below.
Convoy Satellite
Anchor Satellite
Passive C-band SAR
+
Sentinel-1 (selected for further study)
Active C-band SAR (InSAR)
+
Sentinel-1
X/Ku-band SAR
+
Sentinel-1
Thermal Infrared (TIR)
+
Sentinel-1
VIS/NIR/SWIR
+
Sentinel-1
L-band SAR
+
Sentinel-1
Laser altimeter
+
Sentinel-3 (selected for further study)
Passive microwave (L-band)
+
Sentinel-3
Ku-band Scatterometer
+
MetOp-SG (selected for further study)
Passive Microwave (L-band)
+
MetOp-SG
Table 7 Ocean and Ice Convoy Study Derived Concepts
From this list three concepts were chosen for further analysis.
Convoy Satellite
Anchor Satellite
Passive C-band SAR
+
Sentinel-1 (selected for further study)
Laser altimeter
+
Sentinel-3 (selected for further study)
Ku-band Scatterometer
5.6.1.3
+
MetOp-SG (selected for further study)
Table 8 Chosen concepts for further analysis
Audience Feedback
General Comments about the Analysis
• The concept of measurement gap was discussed. Within the convoy studies the term gap was used
to describe aspects such as extensions of measurement scales and synergetic measurements.
• Rather than focusing on measurement enhancements and extension it was discussed to open out
the scope of future studies to embrace cross cutting gaps in Earth science. This implies that Earth
Science must be addressed in a different way and the ocean, sea-ice and land-ice domain must be
assessed together in terms of interactions, interfaces and processes.
• Some of the parameters identified in the study are major and some are relatively minor, such
classification of sea-ice type. This parameter is useful for retrieving sea-ice thickness but if sea-ice
thickness can be derived in a better way such as by using a laser and radar combination then
classification of sea-ice type is not required. The identified parameters need to prioritised and
graded.
• To capture Earth system diurnal processes sub-daily measurement is needed.
Ocean Domain
• There are oceanographic processes which are not operationally resolved and users require more
data on:
o Characterisation of the air-sea interaction
o Characterisation of ocean currents. One highlighted example: ocean surface vectors
o Coastal processes
o Doppler property of the ocean
• Coastal processes are at present poorly understood.
• It was suggested that the passive SAR flying with Sentinel 1 convoy concept should focus on slow
moving phenomena over the ice surface. The use of this concept for ocean applications was seen
as minimal due to de-correlation. It was highlighted that the baselines needed to derive ocean
currents are achievable. Surface current vectors were identified as a measurement gap.
• Operational users who use scatterometer data also use ocean current data. These phenomena are
very dynamic and therefore a high temporal resolution is required. A scatterometer convoy would
help this user community by measuring the Doppler property of the ocean. It was pointed out that
the ocean is an oscillator whose vertical motion is constrained by the wind (which is latitude
dependant).
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Wind and sea surface temperature are two closely linked parameters. An accurate estimate of sea
surface temperature is required in order to derive an accurate wind speed estimate from
scatterometry measurements. Equally, an accurate SST estimate requires a robust wind estimate.
The measurement of these parameters is fundamental to the improvement of operational
oceanography data sets.
Sea-Ice Domain
• The ESA CryoSat mission has now made SARIn acquisitions over the ocean and cryosphere,
which will yield results in the coming year. It was conjectured that sea-ice measurement would be
the next step. For any possible future convoy configuration with Sentinel-3 it was pointed out that
the polar regions at high altitudes would not be captured.
• The combination concept of active radar flying with a laser altimeter is a clear convoy concept and
the benefits of this combination have been known about for some time e.g. very precise
topography, bias mitigation etc. Sea-ice thickness measurement can be captured by a
combination of a laser altimeter and radar tuned to snow measurement.
• Improvements in sub-mesoscale sea-ice thickness measurement are critical.
Land-Ice Domain
• Present freeboard measurement techniques rely upon indirect observation and are not direct
measurements. In the Antarctic, the freeboard measurement is the snow extent and so the real
surface needs to be estimated including measurement of the scattering horizon within the ice
pack.
• Characterisation of the mass balance is still poorly understood. Annual and inter-annual mass
change measurement cannot be performed in isolation. Elements such as the interaction /
coupling with the atmosphere and aspects such as the ice-climate interaction (which has to be
measured on a different time scale) are important. Factors such as snow accumulation and ice
melt need to be better understood. Energy balance, including fluxes are not at present sufficiently
known. High-resolution sounding measurements are needed for features such as glaciers and ice
sheets.
• It was questioned whether the Ku-band scatterometer would be able to measure the snow/ice
interface. Penetration of wet snow at Ku-band is difficult. The Ku-band would be useful to
improve the estimates of the ice thickness.
• Measuring leads and polynirs at high resolution is at present a measurement gap. High-resolution
measurement would have a critical impact when understanding of the surface atmosphere
exchange processes particularly for thin ice in leads.
• Many measurements would benefit from using multiple SAR frequency measurements such as
e.g. ice class classification. Lower frequency measurements were identified for artic sea-ice
thickness measurements including ground-penetrating radar. For the Antarctic, the freeboard
measurements are characterised by the snow pack.
• The Copernicus Sentinels will not provide velocity maps of ice sheets. There is a need to measure
three dimensional ice sheet velocities with a temporal fidelity, which captures this dynamic
phenomenon.
5.6.2
5.6.2.1
ESA EO Convoy Study Latest Results - Land Applications
Identification of Measurement Gaps
Analysis performed by: University of Leicester and a team of science consultants. Results were also
derived from a small workshop held at ESA-ESTEC [AD 2].
Presenter: Neil Humpage, University of Leicester
The aim of the Land Convoy Workshop held at ESA-ESTEC [AD 2] were two fold:
1. To identify the challenges and gaps in current Earth Observation capabilities to study land
surface processes.
2. To develop mission and instrument concepts to address using these gaps, taking advantage of
the possibility to fly in convoy with operational missions such as Sentinels.
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This two day workshop at ESTEC was intended to build on the study team’s understanding of land surface
processes to better identify the future needs and challenges for land surface sensing from space and to
develop Convoy concepts.
A measurement gap analysis [AD 4] was performed based on the results of the workshop [AD 2] coupled
to a wider literature review. Science needs were organised into groups reflecting the observation priorities
in [AD 1] and where necessary additional groups were also included. The focus of the analysis was on
areas where additional satellites could provide additional support to the characterisation of the Land
domain.
Table 9 High-level User Needs
Earth observation variables were identified and assessed together with their associated measurement
needs. These needs and requirements were then assessed against present day and near future in-orbit
capability and a number of measurement gaps were identified, which can be seen below.
I.D.
Variable
Carbon Cycle
G-CC-01
Biomass (direct
measurement)
Gap
Identified User Needs
Sensitivity to biomass at spatial
scales of < 10 km
G-CC-02
Vegetation Height
G-CC-03
Leaf Area Index (LAI)
Better observations of
vegetation structure to improve
biomass estimation.
BRDF data needed.
G-CC-04
Fire Radiative Power
(FRP)
At present only effective LAI
can be derived.
Sensitivity to small fires
< 250 m
10-100 m
< 1-2 years
< 10 t/ha or 20 % accuracy
All forest types, full range of biomass – at least 300
t/ha in tropical rainforest.
10 m to 100 m
< 1 – 2 years
< 4 m accuracy:
< 100 m
< 15 days revisit
< 20 % accuracy
Multi-angle observations for BRDF (G-SE-01)
G-CC-05
Veg. Fluorescence
Measurements < 500 m
Surface Energy
G-SE-01
Surface albedo &
BRDF
Higher spatial res. & multiangle BRDF measurement for
vegetation structure
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< 250 m
> 500 K accuracy
Morning observations not optimum. Afternoon
preferred. MIR needed for fire observation
< 500 m
5 to 10 days
< 5% radiometric accuracy
10 m to 50 m
< 1-30 days revisit
< 5-10 % accuracy
I.D.
G-SE-02
Variable
Land surface
temperature (LST)
Gap
Higher spatial resolution
Identified User Needs
~ 50 m to 100 m, 5 day revisit
< 0.5 K accuracy, NeDT < 0.2 K
> 1 TIR channel
< 100 m
Water Cycle
G-WC-01
G-WC-02
Soil Moisture
Land surface
temperature (LST)
High spatial & temporal
resolution measurement for
crop monitoring
High spatial resolution
< 100 m
< 1 week revisit
< 10g/kg or 5% accuracy
~ 50 m to 100 m, 5 day revisit
< 0.5 K accuracy, NeDT < 0.2
< 100 m to avoid LST anomaly
confusion
Land Use and Land Cover
G-LC-01
Land cover change
G-LC-02
Land surface
topography
Human Population Dynamics
G-HD-01
Urban LST
Urban Emissivity
Urban albedo
Urban land cover
Volcano and Thermal Anomaly
G-VO-01
Measurement of preeruptive thermal
anomalies
G-VO-02
Lava temperature
Regular & continuous global
coverage (high res.)
Lack of wider swath higher
spatial resolution meas.
10 m to 1 km, < 1 week revisit
< 5 % accuracy
10 m to 250 m, < 10 years,
< 10 m accuracy, swath > 100 km
Higher spatial resolution for
urban planning and energy
efficiency applications.
< 25 m (< 500 m sufficient for environmental quality
& urban meteorology applications.
< 1 month revisit (< 1 day for environmental quality &
urban meteorology applications)
< 0.5 K accuracy (LST),
< 5-10% accuracy (albedo)
> 1 TIR (improved emissivity meas. leading to
improved LST retrieval).
Higher spatial and temporal
resolution for environmental
quality and urban scale
meteorology
< 60 m
< 1 week temporal resolution
< 1K accuracy for temperatures up to 360 K
Medium to high-resolution
< 100 m
infrared measurement of
Observations required over target site several times a
temperatures up to 1500 K
day during eruptions.
Table 10 Identified parameters and highlighted measurement gaps in the land domain
5.6.2.2
TIR (Higher resolution and
improved accuracy
Derivation of Convoy Concepts
Presenter: Mike Cutter, Surrey Satellite Technology Ltd (SSTL)
Convoy Concept
Comments
1
Passive C-band SAR
2
3
L-band SAR
+
Sentinel-1
MIR/TIR multi-spectral imager +
Sentinel-2
(wide swath)
Sparse array L-band SAR
+
Sentinel-1
Improvement in veg. 3D structure observation
W-band conical scanner
+
Sentinel-2
LAI using multi-angle.
High resolution TIR
+
Sentinel-2
< 90 m to measure thermal anomalies
Multi-angle imager
+
Sentinel-2
To provide BRDF sampling
S-band SAR
+
Sentinel-1
Interaction of vegetation with water cycle variables.
InSAR C-band SAR
+
Sentinel-1
Improvement in veg. 3D structure observation
Table 11 Derived convoy concepts for Land Convoy Study
4
5
6
7
8
9
+
Operational
Satellite
Sentinel-1
Improvement in veg. 3D structure observation e.g. canopy
height change
Improvement in veg. 3D structure observation
< 200 m LST
From this list of concepts three concepts were chosen for more detailed study
Convoy Concept
1
3
6
Passive C-band SAR
Comments
Improvement in veg. 3D structure observation e.g. canopy
height change. Across track interferometry
MIR/TIR multi-spectral imager + Sentinel-2 (flying 3
Microbolometer solution is proposed. MIR/TIR with high
(wide swath)
hours later, 13:30)
dynamic range up to 1400 K (MIR).
Sentinel-3 at 10:00
< 200 m
JPSS (pm)
ULIS Pico640E detector for MIR (Short term)
High resolution TIR
+
Sentinel-2
< 90 m to measure thermal anomalies (multi-channel)
Table 12 Selected Concepts for further study
5.6.2.3
+
Operational
Satellite Options
Sentinel-1
Audience Feedback
General Feedback
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As a first step, the convoy studies identified assessed the various Earth Science elements and
various Earth System elements such as water cycle, carbon cycle, and surface energy balance. An
opportunity exists to build on this work by designing convoys and constellations aimed at
assessing the interactions between these various elements. One example provided was highresolution evapotranspiration measurement, which connects e.g. water cycle and surface energy
balance.
This approach would benefit the assimilation of models e.g. land surface, land-atmosphere
models.
The temporal scale is critical when characterising dynamic phenomena such as temperature and
heat fluxes etc. A good sampling is required to capture dynamic behaviour and this requires
combining multi-point measurement from convoys, constellations and other observing system
such as satellites in geo-stationary.
Water Cycle
• Uncertainties in the water cycle include river run off and storage change. On a larger scale this
can be estimated with gravity missions but the smaller scales remain challenging.
• Snow related change was also seen as a source of uncertainty within the water cycle (cross over
with Ocean and Ice Convoy Study).
Surface Energy Balance
• A major uncertainty identified for surface energy balance are fluxes relating to land roughness
and therefore vegetation structure. Vegetation structure was discussed in terms of carbon stock
estimates and roughness should also be included. It was pointed out that the ESA Earth Explorer
mission Biomass may be able to provide information relating to vegetation structure.
• The urban energy balance should also be addressed. These phenomena are highly complex and
must be measured on the street scale with high to very high-resolution sensors. The parameters
are similar to the water cycle but measured on a completely different scale. Characterising this
urban energy balance in terms of population dynamics will become increasingly important as
more people move to urban areas. Elements such as urban heat islands are well established but
the characterisation of the urban environment is a complex, much bigger problem. To capture
and characterise dynamics at these scales represents a big challenge. For these scales the
geometry is important, as well as emissivity and LST measurement, population dynamics and
concentration. The parameterisation models currently used do not have sufficient resolution to
capture all the information required and there are very little data to support work in this area.
Carbon Cycle
• The gap relating to vegetation and carbon stocks was discussed in light of the selection of the ESA
Earth Explorer Biomass mission, existing TanDEM-X measurements and plans for the JAXA
ALOS-2 mission. It was pointed out that this gap analysis was performed before the Biomass
mission selection.
• One application for the passive C-band SAR flying with Sentinel-1 convoy concept is the provision
of an annual map of vegetation canopy height at the Sentinel-1 resolution level. These data
coupled with the coarser resolution at P-band of BIOMASS mission data would provide valuable
information.
• For vegetation applications, greater penetration would be obtained by measuring with longer
wavelengths e.g. L-band. A companion SAR flying with the CONAE SAOCOM mission for
example (considering polarimetry) would be useful to characterise both the terrain and the
canopy height. It was highlighted that an ESA study is already underway to study an L-band
passive companion to fly with the SOACOM mission (L-band).
Measuring Thermal Anomalies
• The convoy concept aimed at fire monitoring was discussed. It was highlighted that there was a
need for high-resolution thermal infrared measurement (below 1 km). The use of MCT detectors
is well established. However, the concept presented is based on microbolometers, which do not
require cooling.
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The use of space borne sensors for operational fire monitoring was discussed. It was pointed out
that users fall into two main groups: operational and scientific. Operational users such as fire
response and fire management require a certain temporal resolution, which is not achievable with
a single satellite. However, the system being proposed could provide data to support services such
as air quality and atmospheric emissions. Fires by their very nature are unpredictable and
dynamic characterisation is needed which cannot be obtained from static inventory maps. At
present MODIS data is used at 1 km, which only captures large-scale dynamics and therefore
MODIS measurements may only represent approximately half of the overall fuel consumption. It
was highlighted that the German Aerospace Center (DLR) Bi-spectral Infrared Detection (BIRD)
mission provided excellent data related to fire size distribution while it was operational. However,
due to the nature of the mission it did not provide data on the random nature of fire events. Fire
emission estimates for large events are reasonably well known but the distribution of emissions
elsewhere (untargeted) and the proportion of the total emissions, which are actually being
measured is also unknown. High resolution measurement is needed to capture the full fire size
distribution and a quantitative estimate (measured by a sensor with a suitable saturation
threshold) is then also required to measure radiative energy which is related to fuel consumption
rate, which, when adding an emissions factor yields parameters such as aerosol emission rates
etc.
As the spatial scales increase to e.g. street level, crop level, tree level, the thermal signatures of
these different materials will be highly complex. Therefore understanding and being able to
estimate emissivity at these levels is critical.
Sentinel-2 and Sentinel-3 are tuned to land and ocean applications respectively. The main gap
between Sentinel 2 and Sentinel 3 is a thermal infrared capability (higher resolution than 1 km)
tuned to land processes.
DLR aim to launch the FireBIRD concept comprising two satellites, which has a mid infrared and
thermal infrared capability measuring at 200 m.
5.6.3
5.6.3.1
ESA EO Convoy Study Latest Results - Atmospheric Applications
Identification of Measurement Gaps (Chemistry and Composition)
Presenter: Roland Leigh, University of Leicester
ID
Parameters /
Status
Processes
Gap
No UTLS measurements with very high vertical
C-G1
UTLS 3-d cube for
resolution & horizontal resolution have been
The PREMIER candidate Earth Explorer mission
T, radiative gases,
flown
(EE8) was proposed to fill this gap. As PREMIER
tracers, chemistry
techniques. Measurements would complement
or
approved.
There
are
applicable
was not selected this gap still exists.
Copernicus significantly.
Measurements of O3 into mesosphere, key tracers
Long-term
C-G2
monitoring for the
stratosphere
and
mesosphere
Existing
techniques
are
applicable.
(SF6, CO, N2O), NOy
Measurements would complement GMES.
Long-term monitoring with high accuracy
No planned missions beyond current missions
Monitoring of CO2, CH4, H2O, T, and Halogenated
compounds.
No high vertical resolution measurements of
C-G3
Tropospheric NO2
profile
profile
troposphere and PBL have been flown or
information
going
down
to
the
information
approved. Measurements would complement
A mission design similar to that of SCIAMACHY
would be applicable in this situation
Copernicus.
High
temporal
Previous missions focused on long-term global
spatial
coverage at relatively low spatial resolutions.
of
Previous investigations into diurnal variation
tropospheric NO2
needed to use data from several instruments,
coverage
leading to biases due to inter-comparison
and/or
C-G4
resolution
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Sentinel 4 would provide high temporal resolution
measurements for Europe (with GEMS and TEMPO
providing
coverage
for
Asia
and
the
US
respectively). Cloud clearing and data coverage over
other regions still an issue.
There are no measurements planned at 1 km or
ID
Parameters /
Status
Processes
Gap
higher spatial resolutions. These would assist with
source identification and small-scale air quality
modelling in complex and compact urban areas.
Higher
temporal
and
C-G5
spatial
resolution
of
tropospheric
Spatial and temporal resolution too poor to extract
Tropospheric ozone products exist from TOMS,
detailed information on surface structure and
OMI and GOME-2.
precursor sources. Lack of vertical resolution is a
key issue in use of the data in model assimilation.
ozone
MOPITT provides comprehensive maps of CO on
the global scale, with combined TIR and NIR
C-G6
Tropospheric
carbon monoxide
retrievals
offering
improved
near-surface
sensitivity. SCIAMACHY provide nearer-surface
measurements in the NIR. Measurements also
Significant
uncertainties
in
near-surface
concentrations remain.
available from AIRS, TES and MLS, with some
profile information.
SO2 measurements from many satellites used to
C-G7
Sulphur dioxide
explore volcanic emissions. Measurements from
OMI used in volcanic ash warning systems.
C-G8
Formaldehyde
C-G9
Nitric oxide
C-G10
Hydroxyl radical
derive a 12-year dataset of HCHO.
concentration
measurements
low,
therefore
conclusions
on
features. Temporal monitoring of volcanic emissions
Spatial resolution very limited. Very sparse diurnal
sampling at present, with improvements expected
from temporal coverage of Sentinel 4.
No space-borne measurement of tropospheric
current
v.
anthropogenic sources are limited to very large
is poor.
GOME and SCIAMACHY predominantly used to
No
Sensitivity
from
Closure of NOx budget is not achieved.
space.
Demonstrations of remote sensing have been
No global measurement.
performed from balloon.
Spatial resolution and coverage limited. No diurnal
C-G11
Tropospheric CO2
Total columns from GOSAT, SCIAMACHY and
sampling.
upper tropospheric concentrations from IASI,
observations with PBL sensitivity during night times
No/limited
vertical
resolution.
No
AIRS, TES
and high SZAs. Very limited measurements with
PBL sensitivity over snow and water surfaces.
Spatial resolution and coverage limited. No diurnal
C-G12
Tropospheric CH4
Total columns from GOSAT, SCIAMACHY and
sampling.
upper tropospheric concentrations from IASI,
observations with PBL sensitivity during night times
No/limited
vertical
resolution.
No
AIRS, TES
and high SZAs. Very limited measurements with
PBL sensitivity over snow and water surfaces.
Column
C-G13
Delta D in H2O
averaged
Delta
D
in
H2O
from
SCIAMACHY and GOSAT. Tropospheric Delta D
Low precision of retrievals.
in H2O from IASI, TES and IMG
Aerosol optical depth from MODIS, MERIS,
C-G14
Aerosol
OMI, SEVIRI and others.
Little
composition
Aerosol techniques giving aerosol composition
microphysical properties and composition.
information
available
on
aerosol
and size for UTLS and stratosphere injections
Little information with PBL sensitivity; restricted
C-G15
Tropospheric VOC
Some tropospheric VOCs from IASI (and UTLS
range of VOCs measured so far. Improved errors for
suite
from ACE)
VOCs needed. Simultaneous UTLS measurements
also ideal.
Table 13 Identified Gaps in the Atmospheric Chemistry and Composition Domain
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5.6.3.2
Identification of Measurement Gaps (Meteorology)
Presenter: Ad Stoffelen, Dutch Royal Meteorological Institute (KNMI)
ID
Atmosphere parameter
Status
Gap
Good spatial and temporal coverage by GEOs
M-G1
Horizontal wind profile
(cloud motion vectors); higher quality winds Vertical resolution is poor. Aeolus demo
from LEOs (e.g. MISR) with lower temporal
in trop and strat., but not in convoy
resolution
Wide range of instruments available.
Sounders (e.g. IASI) of primary importance
M-G2
Temperature profile
Sounders lack vertical resolution in
for NWP assimilation. Temporal resolution temperature. Accuracy close to threshold,
will be enhanced with GEO sounders (IRS on
particularly in PBL.
sentinel-4)
Wide range of instruments available.
Sounders (e.g. IASI) of primary importance
M-G3
Humidity profile
for NWP assimilation. Temporal resolution
will be enhanced with GEO sounders (IRS on
sentinel-4)
Aerosol properties (AOD, AI,
M-G4
extinction coefficient, SSA, Angstrom
Currently limited parameters; will be
parameter, aerosol type, particle size
improved with 3MI
distribution) incl. profile
Cloud properties (cloud cover, baseM-G5
height, top-height, phase, COD,
effective radius, size distribution,
Sounders lack vertical resolution in
humidity. Accuracy close to threshold.
Poor in PBL. Extremely variable near
cloud processes, incl. PBL.
Vertical sampling very limited. No active
instruments after EarthCARE. Extremely
variable near cloud processes, incl. PBL.
Horizontal and temporal resolution
Vertical sampling very limited. No active
adequately resolved by wide range of GEO
instruments after EarthCARE. Needed for
and LEO imagers
understanding physical processes.
LWC/IWC) incl. profile
Vertical information and coincident
M-G6
Precipitation properties (intensity,
GPM adequate horizontal and temporal
measurement with clouds/aerosols
type) incl. profile
resolution for monitoring.
lacking. Needed for understanding
physical processes.
M-G7
Vertical-wind profile
No measurements available
Needed for understanding of physical
processes and mixing in the atmosphere.
Table 14 Identified Gaps in the Atmospheric Domain
5.6.3.3
Derivation of Convoy Concepts
Presenter: Karl Atkinson, Astrium Ltd
Convoy Concept
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Operational
Satellite
Broadband light source
+
MetOp-SG (S5)
UV-VIS multi-angle profiler/ mapper
+
MetOp -SG (3MI)
UV/Vis spectrometer
+
Sentinel-3 (SLSTR)
NO2 Lidar
+
S5P
3 micron spectrometer
+
MetOp (IASI, S5)
Aerosol lidar
+
MetOp -SG (3MI/UVNS)
Carbonsat (EE8) + FLEX (EE8) + BIOMASS (EE7)
+
Sentinel-3 (SLSTR)
Lidar
+
MetOp -SG (IR/MW sounders)
Multi-angle thermal infrared
+
MetOp -SG
Extended RO
+
MetOp -SG
Cloud Profiling Radar
+
MetOp -SG
Multi-wavelength cloud aerosol lidar
+
MetOp -SG (Imagers)
Cloud Profiling Radar + Multi-wavelength cloud aerosol lidar
+
MetOp -SG (Imagers)
DIAL Lidar
+
MetOp -SG (Sounders)
Table 15 Derived convoy concepts for Land Convoy Study
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From this list of concepts two concepts were chosen for more detailed study
Convoy Concept
3 micron spectrometer
Multi-angle thermal infrared
5.6.3.4
Operational Satellite
+
MetOp (IASI, S5)
+
MetOp -SG
Table 16 Selected Convoy concepts for further study
Audience Feedback
General Feedback
• A number of convoy concepts were presented and two concepts were selected for further analysis.
The selection process was presented. The concepts that were not taken forward were not
discarded because they lacked scientific merit. In some cases the concept selection was rather
arbitrary based on team expertise.
• In the coming decade a number of satellites have and will be launched which will provide longterm standard products e.g. Landsat, Copernicus Sentinels and this capability needs to be built
upon with additional innovative missions. This is a real opportunity to shape the future in-orbit
landscape. The convoy studies are a first step but the scope should be bigger to include the
definition of Earth System element interactions and interfaces to comprehensively address the
primary measurement gaps.
• Measurements gaps were identified which were addressed by the three Earth Explorer candidate
missions: Biomass, CoReH20 and PREMIER. It was an ESA decision not to study these concepts
in detail within the scope of the Convoy studies. However, following the selection of Biomass, the
gaps identified related to the PREMIER mission and the CoReH2o mission still exist.
• The analysis shown focuses on improving existing measurements.
• The A-Train lessons learned includes a combination of passive and active observing systems.
• To better understand rapidly changing and dynamic phenomena, possible future configurations
(2020-2025) could be: 16 channel imagers in GEO providing observation of the diurnal cycle,
perhaps at least one hyperspectral sounder in GEO, coupled to a constellation of active
instruments in LEO e.g. a lower inclination precessing orbit. Geo-stationary observation was not
considered within the scope of the convoy studies.
• Future observing systems need to be able to capture small and mesoscale processes which exist
within the different atmospheric layers as well as its various interfaces e.g., land-atmosphere,
ocean – atmosphere etc.
• Global climate models at high-resolution scales will not be trivial.
• The convoy team pointed out that their discussions were wider ranging than presented which
included ideas such as wide swath lidars and lidar pointing capabilities.
• Some of the primary atmospheric measurements include composition, temperature and
humidity. It is important when performing atmospheric retrievals that the scene is clear of clouds
because undetected thin cirrus clouds can be present and cause huge measurement biases. A
simple backscatter lidar for composition measurement is essential to measure the scene in order
for a clean retrieval to be performed. The FLEX mission was given as an example of a mission,
which could benefit from this. A simple backscatter lidar could be seen as a support tool for
mission land surface and atmospheric missions making them much more robust.
Aerosol Measurement
• For aerosol measurement there is an ambiguity between scattering and absorption. A backscatter
lidar such as e.g. Calipso or techniques such as polarimetry or spectral imagery does not solve this
problem and alternative solution should be sought.
• There are big gaps relating to precipitation (post GPM), snowfall measurements, and convection
observation measurements, which need to be addressed in the coming decade.
• Other gaps to be addressed include aerosol type, cloud-aerosol interactions and cloud lifetime etc.
• One of the convoy concepts presented included aerosol composition (UV-Vis multi-angle)
however different polarisations were not assessed.
• IPCC reports state that the aerosol measurement uncertainty (both direct and indirect) is still
very high. MetOp-SG-3MI is a first step to addressing this problem. In addition, one possible
constellation could be high-resolution lidars flying with spectropolarimeters with very high
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polarimetric accuracy. If these lidars are flown in convoy with MetOp-SG then the footprints of
these lidars should overlay that of 3MI.
The refractive index can be used to discriminate between different types of aerosol.
Polarisation measurements are important for e.g. aerosol classification retrievals. The convoy
team admitted that this expertise was not within their team. If the multi-angle instrument had
polarisation capabilities this would enhance the concept.
One suggestion for a convoy concept included the combination of an infrared limb sounder and a
lidar. The aim of this concept would be to identify aerosol type and aerosol structure.
Active Instruments
• There are already two lidar missions being developed by ESA. This affected the convoy study
concept selection.
• Active instruments perform better at lower altitudes (rather than around 800 km Sentinel
altitude).
Multi-Angle Measurement
• One convoy concept proposed was a MISR type multi-angle instrument measuring in the thermal
infrared region. The original MISR provides height resolved winds and provides post processed
data sets at 17 km. However, MISR data utilisation in the wind domain has been limited due to a
lack of computation power. The concept proposed would take advantage of new digital
developments and would perform on-board processing. The proposed concept also includes
thermal infrared bands for night time wind measurement.
• MetOp-SG 3MI is also multi-angle and multiband measuring at 4km. The convoy team suggested
that a resolution of 250 m would be useful to measure small-scale processes and features.
Radio Occultation Measurement
• One concept presented was a radio occultation satellite flying with MetOp-SG. The aim would be
for the convoy satellite to fly close to MetOp-SG and obtain multiple occultation measurements
for process studies.
Snowfall Measurement
• Snowfall was identified as a gap and a convoy concept was identified, however, this mission was
not taken forward due to similarities with the Earth Explorer CoReH2O mission candidate, which
was being developed at the time. As the CoReH2O mission as not finally selected snowfall etc.
remains a measurement gap.
5.7
5.7.1
Session 6 : Future Concepts
Science and Applications from a Novel Ocean Surface Vector Wind
Constellation
Presenter: Ad Stoffelen, KNMI
In-orbit scatterometers presented included MetOp-A and -B, OSCAT (Oceansat-2) and HSCAT (HY-2A).
The CEOS Virtual Constellations for GEO were presented which demonstrates the value of collaborative
partnerships in addressing key observational gaps. The focus was on ocean surface vector winds (OSVW).
The World Meteorological Organisation (WMO) requires 6-hourly OSVW coverage in order to
characterize diurnal cycles, mesoscale convective systems, eddy-scale ocean applications and air-sea
interactions. The target users for this data would be national forecast agencies, research and development
communities and commercial companies. Various applications were presented. European data is available
for scientific and operational users. KNMI stated that data exchange with the Indian Space Agency (ISRO)
is now also operational and exchange with the Chinese National Ocean Satellite Application Center
(NSOAS) is just commencing.
Discussion Highlights
• Improved wind measurements are needed and therefore an improved measurement of ocean
surface currents is required. Dynamic phenomena such as coastal surface currents and winds can
benefit from very high temporal resolution measurements. For wind measurements there is a
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demand for backscatter data processing improvements in coastal regions. Institutions such as the
ECMWF and the UK Met Office are implementing ocean currents into data assimilation models.
Scatterometers measure the relative motion between the water and the atmosphere. If
measurement is being taken from a boat then the wind motion measurement is relative to the
fixed Earth and the difference between the measurements is the surface current. The surface
current data is needed to assimilate the scatterometer data into the model. Equally, if the
measurement is being taken from a boat then the model winds are not providing accurate wind
strength estimates and therefore the measurements provided by the scatterometer are better. This
is a complex situation and complementary measurements separated closely in time would provide
a better understanding of the processes under study. A convoy measuring the Doppler signature
of the ocean and wind measurements would be useful.
•
Air-sea interaction and flux exchange is another important issue, which requires further study.
•
Scatterometry can only be useful for operational oceanic applications if the temporal resolution of
the measurements dramatically increased. A figure of 4 to 6 hours was suggested.
Key Points
• Dynamic phenomena require high temporal resolution measurement to fully characterize associated
processes and features e.g. 4 to 6 hours.
• Wind and surface current measurement are closely linked.
• Air and sea interaction and flux exchange requires further study.
5.7.2
The Role of Cloud and Precipitation Radars in Convoys and Constellations
Presenter: Simone Tanelli, NASA-JPL
Radar technologies have continued to advance to support the next-generation of in-orbit cloud and
precipitation measurements. Focus is required on the improvement of measurement accuracy, multiparameter observations, and mass/size/data reduction. Atmospheric radar technology advances cannot
occur in isolation. Improvements in e.g. scientific modeling, such as atmospheric (cloud resolving, GCM,
climate, chemical transport) and hydrological models and applications are needed. The
cloud/precipitation process must be captured and characterized. Multi-frequency radar measurements
are needed to increase measurement dynamic range and to study aspects such as microphysics etc.
Simultaneous measurements of Doppler velocity are also needed to associate dynamics with hydrometer
contents. Time evolution processes also need to be measured e.g. GEO and LEO based radars can study
life cycles. A number of concepts setting out the vision of future concepts beyond GPM and EarthCARE
were presented. High frequency Ka/W band was presented as an optimum choice for observing snowfall.
Doppler is optimum to measure cloud and precipitation processes. Ku/Ka-band measurements are
optimum for monitoring convective precipitation. Ku/Ka/W-band measurements are optimum for
relating clouds to precipitation. These measurements can be co-located with lidar, microwave radiometer,
IR, and polarimeter measurements depending on the specific science goals. Radar and radiometer
synergies reduce the measurement ambiguities. A constellation of small e.g. cubesat type low power
radars in LEO were presented with the aim of providing frequent temporal coverage and synergy with
wide swath GEO and LEO sensors.
Discussion Highlights
• Each atmospheric radar also measures the Earth’s surface e.g. freeze/thaw, soil moisture, wind
motion, altimetry (tuned to atmosphere) with advanced processing and re-tuned an atmospheric
radar could measure land surface phenomena. It was suggested the same front end could be used
with different processing. This would lead to different user communities using the same
instrument to measure different phenomena
• A picture of global convection is needed. Geo-stationary infrared satellites coupled with LEO
radar satellites would be very complementary as GEO-Infrared satellites measure cloud shell/skin
properties and the radar can measure phenomena inside the cloud.
Key Points
• Atmospheric radar technology advances cannot occur in isolation. Improvements in e.g. scientific
modeling are needed.
• Multi-frequency radar measurements are needed to increase measurement dynamic range and
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•
•
study microphysics.
Simultaneous measurements of Doppler velocity are also needed to associate dynamics with
hydrometer contents.
The next generation of atmospheric radars should be defined in the context of multi-instrument
observations in order to mitigate the ambiguities affecting atmospheric remote sensing techniques.
Atmospheric radars also measure the surface and with advanced processing and re-tuning other
phenomena can be measured. This would lead to different user communities using the same
instrument to measure different phenomena.
Convection processes on a global scale are not well understood. Geo-stationary infrared satellites
coupled with LEO radar satellites would be very complementary as GEO-Infrared satellites
measure cloud shell/skin properties and the radar can measure phenomena inside the cloud.
5.7.3
Bi-static Radars with very Large Baselines: Potential Applications
Presenter: Fabio Rocca, Sepienze University of Rome
A number of applications were highlighted including: soil moisture, urban area observation and forest
observation. For soil moisture it was suggested that a multi-static radar with 1-2 pol. passive system at Cband, with small zenith observation angles might improve threefold the soil moisture accuracy due to the
low-negative sensitivity to roughness. Specular observation of soil may provide reasonable moisture
retrieval at L-band using two polarizations. For urban applications the double bounce removal reduces
dynamics and allows for observations of smaller targets. For forest observation bistatic acquisitions can
provide the full covariance matrix leading to tomography measurements within the vegetation layers. This
technique also mitigates double bounce reflections.
Key Points
• Bi- and multi-static SAR with polarimetry is a powerful technique for numerous applications
• The technique mitigates double bounce reflections.
5.7.4
Passive Formation Flying ATI-SAR for Ocean Currents Observation: The
PICOSAR Concept
Presenter: Francesco Lopez-Dekker, DLR
The concept comprises two passive SAR satellites flying with an active SAR satellite. The configuration is
aimed at ocean current measurement using along track interferometry. The baselines between the two
passive SAR satellites are around 100 m. Results of a performance analysis were presented and TanDEMX results were shown. The concept was described on a system and instrument level.
Key Points
• The baselines between the two passive satellites can be tuned to around 100 m (ATI). The passive
satellites therefore can fly some distance away from the active satellite.
• More satellites can provide measurements in multiple dimensions.
• Use of more than one passive satellite mitigates the need for direct link between the active and
passive satellites.
5.7.5
SAOCOM+ A Companion Satellite to the CONAE SAOCOM L-band SAR Mission
Presenter: Malcolm Davidson, ESA-ESTEC
The Argentinian Space Agency (CONAE) invited ESA to launch a companion satellite with the SAOCOM1B satellite. The schedule for launch is the 2016/2017 timeframe. This invitation has lead to a number of
activities focusing on the L-band companion SAR including: application performance studies, an antenna
accommodation study and a satellite platform study. A Concurrent design facility exercise will take place
in Q4 2013 leading to a Phase-A feasibility study starting in 2014. An overview of the on-going analysis
was presented and the current planning for implementation was shown.
Key Points
• A bi-static system comprising a passive L-band SAR satellite flying with an active L-band SAR
(SAOCOM).
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5.7.6
CryoSat-2 and ICESat-2 - Overview of Possible Tandem Operations
Presenter: Tommasso Parinello, ESA-ESTEC
A possible convoy configuration comprising CryoSat-2 and ICESat-2 in the post 2016 time frame was
presented. Close temporal co-registration of measurements from ICESat-2 and CryoSat could enable
measurement of differences in freeboard height over the same locations, leading to a direct measure of
snow depth. Smaller features such as leads would be measured by ICESat-2 and a comparison with
CryoSat should help quantify the lead size, which has implications on freeboard estimates and the mass
volume. For ice sheets, CryoSat’s all-weather capability will provide more observations in cloudy
conditions. The Ku-band radar (CryoSat) has a variable penetration into firn, which adds an uncertainty
to the elevation change retrievals and this is not inherent in the laser observations. The combination also
improves the snow accumulation estimation, sea-ice volume change and mass balance of ice sheets and
ice caps.
The greatest benefits will be realized if there is significant overlap between CryoSat and ICESat-2 allowing
for cross-calibration between the two missions. Existing ESA and NASA collaboration activities were
presented including working groups and campaigns, etc. The implications on CryoSat data and ground
segment still need to be assessed
Discussion Highlights
• It was pointed out that biases between the two spacecraft are unknown and therefore cross calibration
should be performed over different surfaces e.g. ocean, ice sheets. It was suggested that the cross
calibration could be performed at a pre-defined latitude of a particular area of interest rather than at a
particular ascending node longitude.
• This combination of flying an optical instrument with a microwave instrument can lead to interesting
and complex statistical comparison exercise. The instrument measurement geometries are different,
the physical responses to the terrain of the two instruments are also different and the footprint sizes
are again, also different etc.
• The two instruments should be flown closely together otherwise it will be very difficult to interpret the
measurements particularly at the smaller scales due to de-correlation. This will be mitigated somewhat
by cross calibrating at or close to the area of interest.
Key Points
• Laser and radar measurements are complementary.
• Cross calibration will have to be performed over different surfaces at different areas of interest e.g.
ocean, ice sheets.
• This combination of flying an optical instrument with a microwave instrument can lead to an
interesting and complex statistical comparison exercise due to differences in the instrument
measurement geometry, interpretation of instrument response, footprint size and orbit differences
all causing de-correlation.
5.7.7
Global Frequent, High Spatial Resolution, Multispectral TIR Data – An
Forthcoming EO Observational Gap
Presenter: Martin Wooster, KCL, (Author: Simon Hook, NASA-JPL)
In the thermal infrared (TIR) spectral region, signals are measured relating to: surface temperature and
spectral emissivity. To measure emissivity from space requires multiple thermal infrared bands (> 2).
Emissivity relates to the materials composition and if this is not taken into account then the resulting
measurement is brightness temperature and not the actual kinetic temperature. Three applications for
high-resolution thermal infrared measurements were presented. Ecosystem stress and water use,
wildfires and the characterization and understanding of volcanic eruptions. Evapotranspiration (ET) is a
highly dynamic phenomenon, which requires high spatial and temporal resolution. Instruments such as
MODIS (1 km) struggle to capture field and urban scale variations. Vegetation response to temperature
requires more frequent revisits than growth response i.e. ET requires more frequent revisits than NDVI.
Global average biomass burning estimates range from 20 – 40 % of all global carbon emissions. Large
errors exist in the global carbon budget due to a poor knowledge of carbon release from fires (particularly
smaller fires). In order to obtain precise estimates of combusted biomass the amount of radiative energy
released needs to be measured and this is performed using the mid infrared (3-5 micron) region. To
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measure thermal anomalies a high dynamic range is required to mitigate detector saturation.
Measuring carbon fire emissions requires measurements in both the mid and thermal infrared spectral
regions. The mid-infrared spectral region has a greater sensitivity due to the shift in emission peak as the
temperature increases.
For volcanoes high-resolution thermal infrared measure can be used to separate plume emission
characteristics e.g. water, ice, SO2 and silicate ash etc.
Current in-orbit TIR instruments e.g. Landsat-8-TIRS, Aqua/Terra-MODIS, Terra-ASTER etc. all have
limited lifetimes and if replacements are not launched then there will be a strong possibility of a data gap
later this decade.
The NASA Hyperspectral Infrared Imager (HyspIRI) mission concept was presented. This comprises an
eight-band multi-spectral scanner (seven bands between 7.5 – 12 micron and one band with a high
dynamic range at 4 micron) measuring at 60 m. The concept has a revisit of 5 days. A concept comprising
HyspIRI-TIR deployed on smaller satellite was also presented which could be flown in convoy with
Sentinel-2 (or Landsat-8).
Discussion Highlights
• To measure fires effectively there needs to be an understanding of the three phases of fire
development: pre-fire conditions, the fire itself and post fire conditions. However, this can be
application dependent.
• An emissions factor is usually required to characterize atmospheric emission from fires. It is
thought that these factors are dependent upon certain parameters such as e.g. moisture. The
nature of the fuel can also be linked to atmospheric chemistry observations of the burning plume
by measuring the chemical ratios of different gases present in the plume.
• An estimate of the fuel consumption of the fire is important. This estimate is currently obtained
using one of two possible approaches:
o Measuring the burned area.
§ This method relies on converting an area into a mass, which requires the fuel
load per unit area to be calculated, and this is usually obtained from vegetation
growth models.
o Measuring the radiative energy emission from all the fires in a predetermined area
§ This method adds all the fire emissions together, integrated them over time and
then converted this figure into the amount of material (vegetation), which would
have burned in order to produce that energy. This number is relatively constant
across all fuel types. It is a much more direct methodology but this method relies
on measurements from high spatial and high temporal resolution sensors with a
high dynamic range.
• Both methodologies are limited in the case of understory fires i.e. surface fires in forests. When
fires occur in the understory, the trees absorb or block thermal energy release leading to
estimation errors.
Key Points
• Current TIR instruments will soon be beyond their nominal lifetimes with strong possibility of a
data gap later this decade.
• The HyspIRI mission concept was presented. This comprises eight-band multi-spectral scanner
(seven bands between 7.5 – 12 micron and one band with a high dynamic range at 4 micron)
measuring at 60 m.
• A high resolution TIR such as the HyspIRI mission could be flown in convoy with Sentinel-2.
• Vegetation response to temperature requires more frequent revisits than the growth response i.e. to
derive ET requires more frequent revisits (data points) than the derivation of NDVI.
5.7.8
Sentinel for Global Agriculture Requirements
Presenter: Gérard Dedieu CESBIO/CNES
A future (post 2020) satellite constellation concept aimed at agricultural monitoring was presented. This
concept comprises between 4 to 8 satellites with both optical and SAR capabilities. The proposed optical
component has a ground resolution of between 5 to 30 m with a revisit of 1 day. The proposed spectral
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channels include: blue, red and near infrared (as a minimum) and thermal channels at 50 m. The
proposed polarimetric radar component shall be C-band or L-band (TBC) with a spatial resolution of 20
m with three looks. The revisit would be in the order of 10 days. The configuration would have a near time
capability. The aim of this preliminary work is to assess second-generation Sentinel capability and/or
provide support to first generation Copernicus Sentinels e.g. increase revisit and provision of higher
resolution thermal infrared capability.
Discussion Highlights
• The blue channel is used for atmospheric correction to support NVDI estimates.
• ESA pointed out that the next generation of Copernicus Sentinels will be prepared in the 2020s.
Key Point
• Constellation of 4 to 8 microsatellites comprising optical, thermal and radar measurement
capabilities aimed at agriculture monitoring in the post 2020 timeframe.
5.7.9
InfraRed Imaging Sensor Suite – Mission (IRIS-M)
Presenter: Dieter Oetel, Astro- und Feinwerktechnik Adlershof GmbH
The Sentinel Convoy for Land Applications Workshop [AD 2] identified a number of observation gaps /
applications, which can be filled by thermal infrared measurements: fire monitoring (~ 250 m both MIR
and TIR), surface energy balance, water use and human pollution dynamics (< 100 m, multichannel TIR)
and volcano observation (< 60 m, MIR, TIR, hyperspectral TIR for gas emission detection).
The IRIS-M sensor suite concept comprises:
• Medium-high spatial resolution (< 100m) multi-spectral thermal infrared data (up to 7 TIR
bands, between 8 and 12 µm) and mid-infrared data (1 band MIR, at 4µm),
• High spatial resolution (~ 30 m) multi-spectral imaging data with bands in the visible (at 0.5 and
0.6µ m) and near infrared (at 0.86 µm)
• Medium spatial resolution (~ 300 m) hyper-spectral imaging thermal infrared data in the 8 –
13.2µm wavelength region in ~ 90 channels with a spectral resolution of 0.05µm.
The aim is for this sensor to fly on a small satellite platform and for it to be flown with Sentinel-2 or
Sentinel-3. One possible data fusion technique was presented called the Multi-sensor, Multi-resolution
technique (MMT) which works well for agricultural applications.
Discussion Highlights
• As well as land applications infrared imagery can address atmospheric gas emissions and
pollutant/air quality monitoring. There is cross crossing science between land and atmospheric
sounding communities regarding infrared imagery.
• To measure water stress and vegetation thermal emission requires a high temporal resolution,
which lends itself to a constellation approach.
• There may be an opportunity for a thermal imager to be embarked on the ESA FLEX mission
(TBC). High-resolution thermal infrared measurement (~ 50 m) would provide complementary
information. The FLEX candidate mission is power limited, which leads to the exclusion of a
cooled detector.
• It was stated that if high radiometric resolution is needed e.g. 0.2 K at 300 K etc. then this
excludes microbolometers although high spatial resolution solutions >300 m could be possible.
SSTL disagreed with this statement. SSTL stated that appropriate radiometric response at high
resolution is possible with microbolometers if specific techniques are employed.
• If an infrared imager is embarked on the ESA FLEX platform this would provide additional cross
cutting science.
• High-resolution thermal infrared is a measurement gap. A thermal infrared instrument could fly
with Sentinel-2 (extend spectral range beyond SWIR) or Sentinel-3 (zoom lens for existing TIR).
However, the local crossing time may need to be addressed, as fire monitoring for example would
benefit from observations in the afternoon.
• It was pointed out that a thermal infrared capability for Copernicus was investigated some years
ago but an infrared payload was not retained due to programmatic constraints.
Key Points
• High-resolution thermal infrared is a measurement gap. A thermal infrared instrument could fly
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with Sentinel-2 (extend spectral range beyond SWIR) or Sentinel-3 (zoom lens for existing TIR).
An opportunity may exist to fly a co-passenger on the ESA FLEX candidate mission and one
identified option could be an infrared imager (TBC).
•
5.7.10
The Next Generation Gravity Mission Constellation Concept
Presenter: Luca Massoti, ESA-ESTEC
A number of activities have been performed and are on going in the field of gravimetry at ESA, including
system and technology development. Vast experience has been gained in this area because of missions
such as GRACE and GOCE. The Next Generation Gravity Mission (NGGM) aims to build on this
knowledge and experience. An improvement in the spatial and temporal resolution of NGGM will allow
for an improved observation of mass transport signals and a comprehensive optimization of the
constellation reduce de-aliasing and improve signal separation. The results of various studies were
presented including preferred architecture concepts, different orbital configurations system and
constellation trade-offs. Two pairs of satellites were considered, examples configurations included: first
pair in polar orbit, second pair in a medium inclination orbit. A prototype of the laser interferometer
instrument suitable to operate at long inter-satellite distances has been implemented and tested, showing
that the required performance can be attained. Further work was also identified.
In order to have an optimized constellation with multiple partners, the possibility of international
cooperation is actively being explored by ESA. An Inter-agency Gravity Science Working Group (IGSWG)
was set up in early 2013, with the aim of exploring possibilities for cooperation on future gravity satellite
concepts between NASA and ESA for mass distribution and mass transport in the Earth system. In
parallel, the Round Table on Satellite Gravity Exploration China-Euro was held in 2013 in Beijing (China).
The aim was to initiate a dialogue between Europe and China on future gravity field missions and related
science and technology.
Key Points
• Studies are based on previous experience
• Trade-off space includes constellation, satellite, system and payload levels.
• Supporting technology developments are critical to achieve required accuracy and
precision.
• International cooperation is essential and a number of possibilities are being
explored.
5.7.11
The CYNGSS Constellation Mission
Presenter: Chris Ruff, The University of Michigan
The Cyclone Global Navigation Satellite System (CYGNSS) is the NASA Earth Venture Mission selected in
June 2012. The mission comprises eight GPS bi-static radar receivers deployed on separate
microsatellites. The University of Michigan is leading the mission and Surrey Satellite Technology Ltd
(SSTL) in the UK is providing the science payload. The driving science objective is to provide rapid
sampling of ocean surface winds within the inner core of tropical cyclones. The purpose is to understand
the coupling between ocean surface properties, moist atmospheric thermodynamics, radiation and
convective dynamics in the inner core of a tropical cyclone. CYGNSS measures the distortion of GPS
signals scattered from the ocean surface to determine ocean surface roughness and wind speed. Multipoint measurement is critical to improve the sampling. The CYGNSS mission is planned for launch in the
autumn of 2016.
Key Points
• Multi-point measurement is critical to improve sampling.
5.8
5.8.1
Session 7: Programmatic Challenges
Multi-Mission Constellations: Programmatic & Data Challenges
Presenter: Amanda Regan, ESA-ESTEC, (Cheryl Yuhas, NASA-HQ)
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A-Train data from the individual sensors can be used together to exploit data synergies e.g. nearsimultaneity and different observation geometries. Measurement synergy has enabled improved science
product quality. This requires sharing of data at a low level e.g. radiance level (“level 1”). Each A-Train
mission must have stand alone mission objectives but also synergies with other missions must be
demonstrated to enable additional science e.g. Cloudsat and Calipso have individual science objectives but
together provide augmented science return. Each mission must maintain its independence but the
operations of one mission cannot interfere or jeopardize the safety of another.
A constellation level management framework is essential. For the A-Train, this framework is called the
Mission Operations Working Group (MOWG) and comprises dedicated NASA-GSFC constellation
management personnel, NASA-HQ and representatives from each mission team. This group discusses
constellation level topics, addresses constellation level agreements and documentation. The MOWG
manages expectations and provides a communication platform for each of the mission team members.
Data policies vary across nations and national agencies therefore it is important to establish the data
policies at an early stage. Full science benefit cannot be achieved and the investment of a flying a
constellation cannot be realized without an open data exchange.
Instrument retrieval algorithms should be developed and reviewed with the same rigor as the instrument
engineering development. Also cross-comparison of the same geophysical product using multiple
observation techniques and retrieval methods is essential to understanding the phenomena being
observed.
Merging data from multiple sensors with different observation techniques in terms of geometry, coregistration etc. is not a trivial task and resources must be allocated for this task. The on-line NASA ATrain Data Depot (ATDD) has been developed to process, archive, allow access to, visualize, analyze and
correlate
distributed
atmospheric
measurements
from
A-Train
instruments
(http://daac.gsfc.nasa.gov/atdd).
For future convoys and constellations a framework is needed to establish expectations. This includes e.g.
International agreements and data sharing, agency activities and calls which encourage convoys and
constellations, operational configurations which allow safe multi-satellite flying, standardized policies and
procedures which are independent of individual missions. There also needs to be a basis for committing
agency resources to constellation activities with dedicated constellation level management and a
promotion of multi-mission research.
Discussion Highlights
• It was highlighted that missions are required to have stand-alone objectives and that synergies are
seen traditionally as a secondary objective. The example of the next generation gravity mission
was provided as an example, which comprises two pairs of satellites (ESA-NASA cooperation).
For measurements a pair of satellites are needed.
•
The ESA mission SWARM was also highlighted as a mission comprising three satellites, which
provides collective data.
•
It is important that multi satellite missions must be designed and built using a common set of
consolidated requirements.
Key Points
• Agency activities and calls are needed which encourage convoys and constellations.
• The allocation of Agency resources at a constellation level are essential e.g. A-Train MOWG.
• Multi-satellite missions must be designed and built using a common set of consolidated
requirements.
• An open data policy is essential
• Merging data from multiple sensors with different observation techniques in terms of geometry, coregistration etc. is not a trivial task.
• For future convoys and constellations a framework is needed to establish expectations at a
constellation and mission level.
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5.8.2
The Afternoon Constellation Keys for Success
Presenter: Christophe Marechal, CNES
The relative distance between two A-Train missions can vary from between 30 seconds to 300 seconds.
The A-Train control centers are located on the east and west coasts of the United States, France and
Japan. This means different time zones, different cultures, different hierarchies etc. The A-Train
constellation team known as the Mission Operation Working Group (MOWG) meets every six months and
provides a forum for discussion and communication between the different mission teams. The A-Train
MOWG has fostered good working relationships between the mission teams supported by robust and
flexible procedures and processes. The following resources support the A-Train teams e.g.:
• The Constellation Coordination System (CCS). This is an on-line tool enables information
exchange information e.g. mission status and orbital data. A CCS is essential for ephemerides
exchange and to avoid misunderstandings.
• The NASA-GSFC Conjunction Assessment Risk Analysis (CARA) team provides support to the Atrain regarding the assessment of all possible conjunction events. All A-Train missions receive a
daily conjunction analysis summary with a calculated collision probability. When a conjunction
risk is confirmed the CARA team provides additional support regarding maneuver definition and
performs a post-maneuver risk assessment. The CARA team also acts as an arbiter between the
different missions e.g. ascent and exit plans etc. The Landsat-5 / Calipso conjunction led to the
Landsat-5 mission (member of the Morning Train) being invited to join the MOWG.
Some specific A-Train case studies were presented:
• CNES PARASOL mission exit from the A-Train
In 2009, there were identified risks regarding the PARASOL fuel capacity and star tracker
reliability. CNES submitted a new exit plan to the MOWG. A global process for modification
acceptance is essential (change requests). Other team members must be given time to understand
any new plans. The MOWG meeting enabled these plans to be discussed.
• NASA Cloudsat mission re-enters the A-Train
In mid June 2011, Cloudsat exited the A-Train due to a battery anomaly. By the end of 2011,
Cloudsat presented a plan for re-joining the A-Train to the MOWG. A specific review was held to
assess the feasibility of Cloudsat’s return. The original mission comprised Calipso and CloudSat
flying in formation-flying 17 seconds apart. Detailed analysis had to be performed by the flight
dynamics teams (with support from CARA Team). Coordination rules, processes and plans had to
be flexible and adaptable and communication between the mission teams was critical.
• Aqua Inclination Maneuver Change
All A-Train members follow the inclination maneuvers of Aqua in order to ensure a coherent
Mean Local Time phasing, and to keep the same ground track. This is performed by annual
inclination maneuver campaigns, which are collectively predefined at MOWG meetings. In 2012,
Aqua needed to change its drag make-up maneuver (DMU) process due to an anomaly with one of
its instruments. A new plan was presented to the MOWG and a way forward was sought and
agreed.
Discussion Highlights
• International Traffic in Arms Regulations (ITAR) is an issue and can limit access to data relating
to particular systems.
• The set-up of a coherent management structure with clear decision boards is essential.
Key Points
•
Constellation level management (MOWG) and an effective coordinator are critical.
•
Face to face communication between mission teams is critical.
•
•
•
The key to conjunction mitigation is early detection, swift action and effective communication.
A global process for modification acceptance is essential (change requests)
Adaptable processes and flexible teams are essential.
•
The A-train uses the Constellation Coordination System (CCS). Shared tools are for information
exchange is critical.
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•
Respect and trust between mission teams is essential.
5.8.3
A-Train - Implementation Lessons Learned
Presenter: Ronald Boain, NASA-JPL (Author: Angelita Kelly, NASA-GSFC)
The Earth Observing System (EOS) comprises two constellations: Morning Train, Afternoon Train. These
satellites are operated by four entities across three countries: United States (NASA), France (CNES),
Japan (JAXA) and the United States Geological Survey (USGS) is responsible for Landsat. The spacecraft
fly at 705 km in a sun-synchronous orbit with a 16-day / 233 orbit repeat cycle.
The A-Train is not a homogenous mix of identical satellites (e.g. GPS). It comprises several satellites with
diverse instruments, which provide complementary observations. The A-Train satellites fly within
seconds to minutes of each other to enable near-coincident observations of the land, atmosphere, oceans,
and clouds. A-Train sensors comprise passive and active sensors providing both horizontal and vertical
views of the atmosphere. The primary constellation design drivers are safety, radio frequency interference
(RFI) mitigation and sufficient propellant for constellation-specific activities, flexible maneuver capability
e.g. retrograde capability and international cooperation aspects. These aspects include the management
of: different agency development cycles, different time zones and different cultures. Agreements are
required to share information, to manage expectations and reduce uncertainty. Contractor technical
assistance agreement (TAA) documents are required.
The Mission Operations Working Group (MOWG) is the key to communication and coordination between
the mission teams (which includes A-Train science and operations mission members and Landsat
representatives). The meetings are held twice a year with e-mail and teleconferences used extensively.
The mission teams operate their missions independently and maintain their satellites in their respective
positions within their control boxes in the constellation. All missions have a collective responsibility to
ensure the safety of the constellation.
Constellation agreements are negotiated, documented, and signed. The two main documents are the ATrain Operations Coordination Plan and Contingency Plans.
A constellation coordination system (CCS) is implemented to minimize day-to-day coordination. The CCS
monitors the constellation configuration monitoring and provides a status (based on daily orbit data from
the missions), including advance warning of predicted control box violations and enables teams to
exchange orbital data products. Most A-Train maneuvers require minimal coordination. However,
Inclination Adjust Maneuvers (IAMs) require additional coordination and managerial effort. A NASA-US
Air Force agreement exists to provide notification of predicted conjunctions between A-Train satellites
and other space objects e.g. orbital debris.
The A-Train has a set procedure for making changes to the constellation in order to accommodate new
science and/or operational requirements. The first step is that a configuration change request is
submitted to the MOWG for consideration and discussion.
The A-Train operates an open data policy and data access is facilitated through the A-Train data depot
(ATDD - http://disc.sci.gsfc.nasa.gov/atdd). Other mechanisms include: ICARE developed by CNRS URL: http://www.icare.univ-lille1.fr/ and EOSDIS, developed by NASA - earthdata.nasa.gov.
All missions must have a safe exit plan in place, which is agreed by the MOWG. Constellation exit is
viewed as a penultimate step prior to decommissioning. The satellite must plan to leave before it presents
a danger to other mission within the A-Train.
Agreements are essential to ensure that there is a mutual understanding of the terms governing the interagency relationship. Contractor/private industry personnel negotiate Technical Assistance Agreements,
which are then signed by the individual mission teams.
Space agencies or constellation “owners” need to have a long-term vision for establishment, evolution,
and retirement of constellations. Long term planning is needed and replenishment strategies need to be
established for existing constellations to enable the constellation to evolve and maintain critical data
streams.
Satellite missions must not be designed in isolation. When new missions and constellations are being
designed the existing landscape must also be considered in terms of possible measurement synergy
opportunities. If a satellite is being considered for constellation inclusion then current constellation teams
are consulted (typically at the next MOWG meeting).
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Discussion Highlights
• For NASA satellites there is a technical and scientific risk assessment review including estimated
lifetime, which must be completed every two years. The respective programme managers at
NASA-HQ conduct these reviews and based on the results NASA-HQ decided if the mission is
able operate for another two years.
• The NASA managed A-Train MOWG is not chartered to assess the risk of another agency’s
satellite e.g. CNES or JAXA.
Key Points
• The design driver is that the whole is greater than the sum of its parts.
• Safety, communication and coordination are key.
• Satellite missions must not be designed in isolation. When new missions and constellations are
being designed the existing landscape must also be considered in terms of possible measurement
synergy opportunities.
• Constellation level management is essential. For the A-Train there is a Mission Operations Working
Group (MOWG) comprises members from each mission team.
• If a satellite is being considered for constellation inclusion then current constellation teams must be
included in the decision process.
• All missions most be considered on a constellation level.
• Sufficient propellant is required for foreseen and unforeseen constellation-specific activities.
• Flexible maneuver capability is required e.g. retrograde capability
• Safe constellation exit plans must be in place
• All the missions operate within predetermined control boxes
• Develop processes and tools for: automated monitoring of constellation status, contingencies,
enabling configuration and operational changes, conflict resolution and orbital debris mitigation
• Ensure open data sharing and distribution
• Document agreements are essential including the definition of international interfaces
5.8.4
The Orbital Registry Proposal
Presenter: Ryan Frigm, a. i. Solutions, (Author: Lauri Newman, NASA-GSFC)
The Conjunction Assessment Risk Analysis (CARA) aim at NASA-GSFC is to protect NASA robotic assets
from threats posed by other space objects.
The CARA team (for unmanned missions) supports around 65 spacecraft in LEO, GEO, and HEO orbits,
including e.g. all operational unmanned NASA, USGS, NOAA missions, and some international partner
missions etc.
ITU guidelines exist which limit the orbit choice of new spacecraft based on radio frequency interference.
There is no similar mechanism for spacecraft to ensure that new orbit assignments are chosen to avoid colocations. It was highlighted that historically, some repeating conjunctions could have been avoided if
other missions had been taken into account. Some examples of these conjunctions were presented.
The NASA Orbital Registry was presented as one method to mitigate these problems. The registry would
be a central repository for orbit requirements, placements and changes to existing missions. Risk analysts
who could identify possible problems and provide recommendations for alternative placement location if
needed would operate the registry. This foresight would improve operations effectiveness and mitigate the
need for emergency close approach operations, which are costly in terms of manpower and the cost of the
satellite hardware if a collision occurs. NASA would only have enforcement power for issues relating to
NASA assets. Other assets would be managed voluntarily by each individual owner/operator.
An international registry would lead to joint working groups, information sharing, and joint analysis. In
the short term NASA would like to collect point of contact information from other operators to resolve
these issues. Possible implementation activities were presented. Ultimately, an international registry
would ensure that co-locations are mitigated and the risk of collisions is reduced.
Discussion Highlights
• The registry would be cost effective as orbit choices could be assessed before launch against a
landscape of existing in-orbit missions. Emergency avoidance maneuvers would be mitigated and
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•
any orbit changes could be planned in advance.
Contributions to the orbital registry would be voluntary and uploaded data would be visible to all.
Key Points
• No missions should be designed in isolation
• Mission orbit choices can be assessed pre-launch.
• Cost effective as the price of collision is high and the additional manpower needed to perform
emergency operations is not trivial.
• Any potential co-location avoidance maneuvers can be planned in advance.
• An international registry would lead to joint working groups, information sharing, and joint analysis.
5.9
Session 8: Concluding Remarks
This workshop is a first step to assessing convoys and constellation concepts for Earth Observation on an
international level. The following provides an overview of the concluding remarks and discussion.
Copernicus Sentinels
• The Copernicus Sentinels is a constellation infrastructure in itself and possible synergies should
be exploited. The Sentinels do not fly in convoy with each other but further activities focused on
synergetic use of Sentinel data and data augmentation on a constellation level should be
considered.
International Cooperation
• International cooperation is essential.
Cross Crossing Science
• Large cross cutting science problems need to be identified and characterised and any derived
concepts need to be mapped to this analysis.
• Constellations provide a unique opportunity to measure the interfaces and interactions between
Earth Science Domains, which at present are not well defined.
• Synergy between complementary measurements such as observations from active and passive
instruments e.g. laser and radar concepts should be explored. Cross cutting applications exist
spanning many Earth system domains.
High Resolution Measurement
•
Complex and dynamic phenomena require high-resolution measurement (spatial and temporal).
•
Higher resolution sensors are needed to capture smaller scales and characterise dynamic cycles
such as urban measurements, hydrology, freeze/thaw cycles, land roughness and vegetation
structure.
•
Sub-daily revisit is needed for many applications to capture phenomena such as diurnal cycles etc.
e.g. sampling cryospheric phenomena.
•
Higher resolution data supports improved model development.
•
Three-dimensional measurement is needed to comprehensively capture dynamic and complex
processes such 3D vector motion.
Measurement Synergy
• Missions can no longer be designed in isolation. Now, when new missions are developed the
existing landscape and possible measurement synergies must be considered for augmented
science return.
• Active and passive instruments provide complementary measurements and should be considered
together.
• LEO and GEO combinations to provide complementary measurements.
Constellation Lessons Learned
• Constellations require vision and strong agency support.
• Effective management at the constellation level is essential.
• For constellations to operate safely, guidelines /‘rules of the road’ must be established and agreed.
• For the satellites operating within a constellation an understanding of the fuel budget is critical
e.g. consumption, use of fuel for unforeseen orbit manoeuvres.
• Flexible maneuver capability is required e.g. retrograde capability
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•
•
For each satellite flying closely together within constellation, a full understanding of all possible
spacecraft modes is seen as critical to prevent unforeseen close approaches e.g. propulsive safe
modes etc.
Any mission must be able to stand-alone in terms of its science objectives and provide augmented
science return when flying together with other missions.
Highlighted Concepts for further consideration
• A suite of instruments is needed to measure from the top of atmosphere (TOA) to ground level.
These instruments can be separated in time (along or across track), space (distributed spacecraft
or in a train etc.) or view in different directions to capture phenomena in three dimensions.
• The combination of active and passive instruments provides complementary data (as stated
previously).
• Possible laser and radar synergies. This combination addresses applications in both the
atmospheric and cryospheric domain.
• Measurements in the high-resolution -spectral range are needed.
Ø E.g. TIR + Sentinel-2, multiple TIR channels to separate emissivity and temperature.
• GEO and LEO satellites combinations would be a powerful technique to capture dynamic
processes.
6
WORKSHOP KEY MESSAGES
The figure below provides an overview of the key messages from the workshop. The key messages are
identified and discussed in the sections below.
Table 17 Workshop Key Messages
6.1.1
Future Constellation Science and Measurements
Key Message 1.1: Constellations must focus on cross cutting science
• Large cross cutting science problems (e.g., interactions between Earth science domains and
Earth science cycles such as energy, water and carbon) need to be identified and characterised
and any derived constellation concepts need to be mapped to this analysis.
• Constellations provide a unique opportunity to measure the interfaces and interactions
between Earth Science Domains.
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Key Message 1.2: Constellations can exploit complementary measurements
• Cross-comparison of the same geophysical product using multiple observation techniques and
retrieval methods is essential to understanding the phenomena being observed.
• Active and Passive instruments
o Active and passive instruments provide complementary measurements. Using both
types of instruments together can provide excellent opportunities for cross comparison
and error checking.
o Measuring the same phenomena using different instruments based on different physics
leads to increased confidence that the process being measured is being properly
understood.
• Simultaneous measurements (separated in time, space and viewing direction etc.)
o Identical/complementary measurements separated in time / space / both following a
reference ground track to capture dynamics processes.
o Measurement from e.g. limb and nadir viewing directions can be invaluable to
characterise processes and phenomena occurring in three dimensions e.g. Earth
Explorer 8 candidate mission PREMIER and MetOp.
• Instruments in LEO and GEO
o Instruments in LEO and GEO can provide highly complementary measurements.
Key Message 1.3: Long term sustainable scientific data
•
The Earth System is a highly complex system with processes and phenomena occurring over a
wide range of spatial and temporal scales. Multi-satellite data sets show that these processes
and phenomena are all interlinked and fast processes project onto the longer scales. The key is
to understand how the system evolves through sustained and long-term measurements and not
just by providing short-term intermittent measurements.
The key is to understand how the system evolves through sustained and long-term
measurements. The design of scientific missions as independent experiments with a relatively
short life time and lack of firmly planned continuity affects the development of potential
constellations, which may be built-up in time.
Key Message 1.4: High resolution measurements
• Complex and dynamic phenomena require high-resolution measurements in both the spatial
and temporal domains.
• Higher resolution sensors are needed to capture smaller scales and characterise dynamic
cycles.
• Sub-daily revisit (which is possible with multiple satellites) is needed for many applications to
capture phenomena such as diurnal cycles etc.
• Examples requiring high resolution observations were cited across all Earth Science domains
e.g. the measurement of mesoscale and sub-mesoscale oceanographic features, improved wind
measurements, ocean and particularly coastal surface currents, land cover complexity and
dynamics (including cryosphere), surface energy balance, urban applications, water including
snow, snowfall and sea-ice, etc.
• Higher resolution measurement supports improved model development.
• Three-dimensional measurements are needed to comprehensively capture dynamic and
complex processes. One example cited was 3D vector motion.
Key Message 1.5: Constellation level data products
•
•
Constellation level data products must be identified and resources put in place to generate such
products.
•
Cross-comparison of the same geophysical product using multiple observation techniques and
retrieval methods is essential to understanding the phenomena being observed.
Merging data from multiple sensors with different observation techniques in terms of
geometry, co-registration etc. is not a trivial task and resources must be allocated for this task.
Key Message 1.6: Calibration
• Calibration is critical to ensure data consistency over long time series particularly for climate
monitoring.
•
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Robust calibration enables effective data merging from various sources and it allows data gaps
to bridged.
• One instrument acting as a reference calibrator can be used to enhance the return of other
instruments.
Key Message 1.7: Co-registration
• The issue of co-registration of multiple sensors flying in the train is a complex problem and
should not be overlooked. Issues such as differing sensor resolution and swath width must be
addressed including the problem of cloud movement and characterization.
Key Message 1.8: Instrument retrieval algorithms
• Instrument retrieval algorithms should be developed and reviewed with the same rigor as the
instrument engineering development.
•
6.1.2
Constellation Lessons Learned
Key Message 2.1: Cooperative sensing requires a paradigm shift
• Flying in a constellation requires a shift in thinking from mission level to constellation level.
Acknowledgement that certain mission activities may impact other missions e.g. data sets, orbit,
downlink etc. These considerations need to be identified, communicated, managed and resolved
on a constellation level
• Missions flying in constellation cannot be considered in isolation. Cooperative sensing may add
some complexity and cost but ultimately it can provide great benefits and augmented science
return.
• Any developed mission must be able to stand-alone in terms of its science objectives and provide
augmented science return when flying together with other missions.
Key Message 2.2: Agency support and effective management at constellation level
• Strong agency support and vision are essential.
• Effective management at the constellation level is critical coupled to a coherent management
structure with clear decision boards
• For future convoys and constellations a framework is needed to establish expectations. This
includes e.g. international agreements and data sharing, agency activities and calls which
encourage convoys and constellations, operational configurations which allow safe multisatellite flying, standardized policies and procedures which are independent of individual
missions.
• There also needs to be a basis for committing agency resources to constellation activities with
dedicated constellation level management and a promotion of multi-mission research.
• Constellation level activities require careful planning and agreement e.g. manoeuvre campaigns
etc.
Key Message 2.3: Orbital considerations
• Definition of the reference ground track is critical.
• The use of control boxes or similar with buffers to maintain constellation safety is critical.
• Definition of the phasing at the poles is important to prevent satellite conjunctions
Key Message 2.4: Spacecraft Implications (highlighted & discussed during the workshop)
• BOL and EOL planning
o Mission objectives must drive the mission until the spacecraft health reaches a limit.
There is a time when the satellite needs to de-orbit from the constellation. BOL and EOL
planning must be identified, assessed and agreed at an early stage of development and
then periodically iterated as the spacecraft moves through its development and in-orbit
phases.
• Orbit choice
o The orbit choice may be a compromise between instrument capabilities and the science
benefits of flying in a constellation e.g. active instruments flying in a constellation at a
higher orbit.
o Definition of the reference ground track is critical.
o For EOL / de-orbit from the constellation an alternative orbit should be identified
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before launch.
Propellant
o Typically more propellant is required when flying in a constellation:
o Safe orbit insertion
o Safe in-orbit manoeuvres
o Safe de-orbit
o For the satellites operating within a constellation an understanding of the fuel budget is
critical e.g. consumption, use of fuel for unforeseen orbit manoeuvres.
• Flexible manoeuvre capability
o Flexible maneuver capability is strongly advised e.g. retro-firing capability
• Spacecraft modes
o For each satellite flying closely together within constellation, a full understanding of all
possible spacecraft modes is seen as critical to prevent unforeseen close approaches e.g.
propulsive safe modes etc.
• Communication between satellites in the constellation
o Additional resources may be needed e.g. transponders etc. to communicate with other
satellites in the constellation.
• Mass memory
o Depending on the design more mass memory may be needed.
• Interference
o Mutual irradiation from satellites flying together can be a design constraint.
• Uplink and downlink design
o When satellites are flying closely together the uplink and particularly the downlink must
be carefully assessed (particularly for satellites with high data rate sensors on-board).
• Programmatic impact
o When different satellites are flying together the programmatics of one satellite may
impact another particularly if one satellite is reliant on the measurements of another e.g.
different agency development cycles etc.
Key Message 2.5: Constellation can provide mission flexibility
• Constellations provide flexibility to address foreseen and unforeseen issues such as sun glint
mitigation etc. e.g. the spacecraft can be separated and re-aligned etc.
Key Message 2.6: Established constellation agreements, policies and codes of practice
• For future convoys and constellations a framework is needed to establish expectations.
• Establishment of coherent constellation level agreements, policies and code of practice must be
signed by all parties addressing all phases of the mission lifetime e.g. orbit insertion, operation,
end of life (EOL) operations.
• A robust and transparent process for constellation issues is critical e.g. BOL, change requests,
EOL etc. Coordination rules, processes and plans have to be flexible and adaptable and
communication between the mission teams is critical.
• Establish what data should be shared and a means to coordinate and communication
information.
• Agreements are essential to ensure that there is a mutual understanding of the terms governing
the inter-agency relationship e.g. for the A-Train Contractor/private industry personnel
negotiate Technical Assistance Agreements, which are then signed by the individual mission
teams.
• A basis is required for committing agency resources to constellation activities with dedicated
constellation level management and a promotion of multi-mission research.
Key Message 2.7: Understanding differences when working in cooperation
•
•
Cooperation with other agencies (either at a national or international level) requires an
understanding of different cultures, different methods of working, different development cycles,
different time zones and different motivational factors. These aspects should not be under
estimated.
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6.1.3
Highlighted Convoy Concepts
Key Message 3.1: Measurement combinations provide complementary measurements
• A suite of instruments is needed to measure from the top of atmosphere (TOA) to ground level.
• The A-Train is based on measuring the same phenomena with different sensors based on
different physics. This multi-sensor approach provides augmented science return across
different observations, platforms and sensors. This approach enables data products to be
independently calibrated.
• One example discussed focused on Calipso-Caliop (Lidar) and Aqua-MODIS, which provide
atmospheric retrievals based on different physics. Active instruments can validate the retrievals
of passive instruments. One example discussed focused on Calipso-Caliop (Lidar) and AquaMODIS, which provide atmospheric retrievals based on different physics. The Aqua-MODIS
retrievals rely on inputted light scattering models and these can be calibrated using the lidar on
board the Calipso spacecraft.
• Measuring phenomena with different sensors based on different physics and obtaining similar
results provides confidence that the processes and phenomena are being well understood.
Key Message 3.2: Identical or complementary measurement combinations separated in
time / space / viewing direction
• Identical/complementary instruments can be separated in time (along or across track) and / or
space (distributed spacecraft etc.) to characterise dynamic phenomena
• Different viewing directions e.g. limb and nadir can be used to characterise processes and
phenomena occurring in three dimensions e.g. Earth Explorer 8 candidate mission PREMIER
(Limb) and MetOp (Nadir).
Key Message 3.3: Specific Convoy Concepts which were highlighted (non-exhaustive list)
• Laser and radar combinations
o Laser and radar instruments flying together in a coordinated way provide
complementary measurements, which, could provide cross cutting science and address
applications across numerous Earth Science domains. Examples included
Cloudsat/Calipso (A-Train), and the possible tandem operations of Cryosat-2/ Icesat-2.
• Higher resolution thermal infrared < 60 m – 250 m
o Measurements in the thermal infrared spectral range are needed for numerous Earth
Science domains.
o Current in-orbit TIR instruments e.g. Landsat-8-TIRS, Aqua/Terra-MODIS, TerraASTER etc. all have limited lifetimes and if replacements are not launched then there
will be a strong possibility of a data gap later this decade.
o Multiple TIR channels are needed to separate emissivity and temperature.
o Mid infrared and thermal infrared are needed to measure fires and thermal hot spots
(with additional visible channels for context).
o To measure thermal anomalies a high dynamic range is required to mitigate detector
saturation.
o There is cross crossing science between land and atmospheric sounding communities
regarding infrared imagery
o Flying a thermal infrared imager with Sentinel-2 was highlighted.
• Bi-static and multi-static SAR
o Passive SAR concepts flying together with active SAR satellites were highlighted: single
pass and repeat pass interferometry in L-band (SOACOM-CS) and C-band (ESA EO
Convoy, DLR PicoSAR concept).
o Constellations of active SARs flying together. The TanDEM-X mission was presented
and future concepts such as bi-static SAR for applications such as ocean current
observation, soil moisture measurement, urban area characterisation and forest
tomography were also highlighted.
• Multi-frequency SAR
o Multi-frequency SAR measurements (SAR satellites of different frequencies flying
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•
•
•
together) were discussed as a way to increase the dynamic range and due to different
responses build up a picture of phenomena being measured.
Next generation Atmospheric Radar Satellites
o The next generation of atmospheric radars should be defined in the context of multiinstrument observations in order to mitigate the ambiguities affecting atmospheric
remote sensing techniques.
o Atmospheric radars can also measure the surface and with advanced processing and retuning other land surface phenomena could be measured. This would lead to different
user communities using the same instrument.
o A backscatter lidar to provide support data for other missions
Earth Explorer Candidate Missions not selected were highlighted:
o PREMIER flying with MetOp
o CoReH2O (X/Ku-band SAR) flying with Sentinel-1
A backscatter lidar to provide support data for other missions
o The lidar can provide support data for existing missions to establish scene
characteristics e.g. remove unwanted clutter in the actual measurement such as the
presence of thin cirrus clouds
Key Message 3.4: Measurement synergy concepts
•
LEO and GEO concepts flying together
o Coordinated GEO and LEO satellites combinations were highlighted as a potentially
powerful technique to capture dynamic processes on global and local scales.
o One example: Use GEO IR satellites /LEO radar satellites to build up a picture of
global convection. The GEO-Infrared satellites measure cloud shell/skin properties
and the radar can measure phenomena inside the cloud.
6.1.4
Future Constellation Design
Key Message 4.1: Measurement Synergy
Missions can no longer be designed in isolation. When new missions are developed the existing
landscape and possible measurement synergies must be considered for augmented science
return. Constellation aspects should be highlighted in Agency calls e.g. ESA Earth Explorers etc.
Key Message 4.2: Copernicus Sentinels
• Copernicus represents a stable long-term programme for Earth Observation into 2030s. The
Copernicus Sentinels are a constellation infrastructure and possible synergies with other
systems should be explored. The Sentinels do not fly in convoy with each other but further
activities focused on synergetic use of Sentinel data and data augmentation on a constellation
level should be considered. Aspects such as Systems of Systems can be considered.
Key Message 4.3: Anchor Satellites
• Satellites such as EOS-Aqua, Landsat series and the planned Sentinels can provide long-term
anchor points for future constellations.
Key Message 4.4: Orbit Choice
• Constellation participation depends upon the attractiveness of the orbit.
Key Message 4.5: Data policy, data management and distribution
• Data policies vary across nations and national agencies therefore it is important to establish the
data policies at an early stage.
• The data combination, processing, distribution and storage for a constellation must be carefully
assessed and resources must be allocated.
• Merging data from multiple sensors with different observation techniques in terms of geometry,
co-registration etc. is not a trivial task and resources must be allocated for this task.
• Full science benefit cannot be achieved and the investment of a flying a constellation cannot be
realized without an open data exchange.
•
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Key Message 4.6: Replenishment Strategy
• Any constellation must have a viable and robust replenishment strategy
Key Message 4.7: International Cooperation
• International cooperation is essential. Constellations enable international cooperation to ensure
an optimum return / effort ratio.
7
WORKSHOP RECOMMENDATIONS
Based on the results and discussion at the 1st International Earth Observation Convoy and Constellations
Workshop, a number of recommendations were identified for future areas of further study. These can be
seen below.
Recommendation – Constellations to focus on cross cutting science
• The convoy studies focused on extending scales of known parameters. It was recommended to
open out this analysis away from incremental deltas related to known parameters and move
towards broader cross cutting measurement gaps which are needed to comprehensively
understand the Earth system e.g.:
o Characterising the interfaces and interactions between the various Earth system domains
e.g. cycles.
o Identifying and understanding the various flux exchanges and their impact on the Earth
System.
• Therefore, future science activities must focus on the interactions, interfaces and
connections between the classical Earth Science domains. These activities can provide a
roadmap for future constellations. One example provided was high-resolution evapotranspiration
measurement, which essentially connects the water cycle and the surface energy balance. This
approach would also benefit model assimilation e.g. land surface, land-atmosphere models.
Recommendation – Cooperative sensing
• There needs to be a fundamental paradigm shift towards ‘cooperative sensing’ when
defining new missions. New missions cannot be designed in isolation. At present Agencies select
missions often on a case-by-case basis.
•
A formal programmatic framework is required for constellation missions. This framework would
include elements such as rules for international or inter-agency cooperation, data policy,
information exchange etc.
Recommendation – Anchor Satellites
Copernicus is a constellation in itself. The Sentinels and other missions such as Landsat follow on
concepts etc. can act as anchor satellites for additional missions.
Recommendation – Identified Convoy Concepts
A number of convoy concepts were highlighted. These included:
• A combination of passive and active measurements provides the most comprehensive
science return, due to synergy in information content. Laser and radar synergies were particularly
highlighted.
• Higher resolution thermal infrared (< 60 m – 250 m).
• Bi-static and multi-static SAR (C-band and L-band were highlighted)
• Multi-frequency SAR measurements comprising SAR satellites of different frequencies
flying together.
• The next generation atmospheric radars should be defined in the context of multiinstrument observations in order to mitigate the ambiguities affecting atmospheric remote
sensing techniques
• Earth Explorer Candidate missions which were not selected were highlighted e.g.:
o PREMIER (limb view) with flying with MetOp (nadir view)
o CoReH20 (X/Ku-band SAR) flying with Sentinel-1 (C-band SAR)
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Recommendation
• It was highlighted that one area of improvement for future observing systems is the ability to
capture dynamic small-scale processes. For these types of observations high spatial
resolution and high temporal resolution were identified as critical. Examples included heat
flux characterisation, velocities, diurnal cycles etc.
• A good sampling is required to capture dynamic behaviour and this requires combining multipoint measurement from convoys, constellations and other observing system such as GEO
satellites. Activities focusing on combining LEO and GEO measurements were highlighted.
Recommendation – Multi-Agency Constellation Handbook / Guidelines
Produce a multi-agency constellation implementation handbook / set of guidelines based on lessons
learned. This document can then become an agreed starting point for future international cooperation.
8
NEXT STEPS
•
•
•
•
•
The EO Convoy studies shall be completed (Land study and Atmosphere study are still on-going)
by 2014. Additional work is foreseen.
Dedicated science studies are needed which depart from the classical Earth Science domains such
as Land, Ocean, Atmosphere etc. and focus on the interactions between the various domains such
as those defined in the water, carbon and surface energy cycles.
Further work is needed to identify needs for further dedicated technical studies focusing on
multi-point measurements.
Continue collaborative discussions with NASA and other space agencies in view of other potential
opportunities.
Use workshop recommendations for next Earth Explorer calls, as a stimulus for additional ideas.
9
APPENDIX 1 – WORKSHOP COMMITTEES
9.1
Organising Committee
Name
Affiliation
Country
Amanda Regan
ESA-ESTEC
Netherlands
Diego Fernandez
ESA-ESRIN
Netherlands
Pierluigi Silvestrin
ESA-ESTEC
Netherlands
Cheryl Yuhas
NASA-HQ
USA
Hal Maring
NASA-HQ
USA
9.2
Science Committee
Name
Affiliation
Country
Ad Stoffelen
KNMI
Netherlands
Alberto Moreira
DLR
Germany
Andrew Shepherd, Anna Hogg
Leeds University
UK
Bertand Chapron
Ifremer
France
Bob Su
ITC
Netherlands
Bruce Wielicki
NASA-LaRC
USA
Chip Trepte
NASA-LaRC
USA
Craig Donlon
ESA-ESTEC
Netherlands
Dave Donovan
KNMI
Netherlands
Deborah Vane
NASA-JPL
USA
Didier Tanré
CNRS
France
Gerhard Krieger
DLR
Germany
Graeme Stephens
NASA-JPL
USA
Haruhisa Shimoda
Tokai University/JAXA
Japan
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Heiko Balzter
Leicester University
UK
Helmut Rott
University of Innsbruck
Austria
Irena Hajnsek
DLR
Germany
Jacque Pelon
CNRS
France
Joerg Langen
ESA-ESTEC
Netherlands
John Remedios
University of Leicester
UK
Johnny Johannessen
NERSC
Norway
Jose Moreno
University of Valencia
Spain
Jose Sobrino,
University of Valencia
Spain
Klaus Scipal
ESA-ESTEC
Netherlands
Kurt Thome
NASA-GSFC
USA
Laura Candela
ASI
Italy
Malcolm Davidson
ESA-ESTEC
Netherlands
Mark Drinkwater
ESA-ESTEC
Netherlands
Martin Wooster
Kings College London
UK
Massimo Menenti
University of Delft
Netherlands
Paco Lopez-Dekker
DLR
Germany
Paul Ingmann
ESA-ESTEC
Netherlands
Philippe Veyre
CNES
France
Ridha Touzi
CCRS
Canada
Stella Melo
CSA
Canada
Steve Platnick
NASA-GSFC
USA
10
APPENDIX 2 – LIST OF PARTICIPANTS
Name
Company
Country
Amici, Stefania
Istituto Nazionale di Geofisica e Vulcanologia
ITALY
Andrew, Shepherd
University of Leeds
UNITED KINGDOM
Atkinson, Karl
Astrium
UNITED KINGDOM
Balzter, Heiko
University of Leicester
UNITED KINGDOM
Battaglia, Alessandro
University of Leicester
UNITED KINGDOM
Boain, Ronald
Jet Propulsion Laboratory/NASA
UNITED STATES
Bonerba, Michele
OHB System AG
GERMANY
Borgeaud, Maurice
European Space Agency
ITALY
Buongiorno, Maria Fabrizia
Istituto Nazionale di Geofisica e Vulcanologia
ITALY
Burbidge, Geoff
Astrium Satellites
UNITED KINGDOM
Callies, Joerg
ESA-ESTEC
NETHERLANDS
Cantie, Roland
Astrium
FRANCE
Chapron, Bertrand
Ifremer
FRANCE
Ciccolella, Antonio
ESA
ITALY
Cornara, Stefania
DEIMOS Space
SPAIN
Coulomb, Ludovic
European Space Agency
NETHERLANDS
Court, Andy
TNO
NETHERLANDS
Covello, Fabio
ASI
Cutter, Mike
SSTL
ITALY
UNITED KINGDOM
Danielson, R.
NERSC
NORWAY
Davidson, Malcom
ESA-ESTEC
Davies, Philip
SSTL
NETHERLANDS
UNITED KINGDOM
de Groot, Zeger
Innovative Solutions in Space BV
NETHERLANDS
Dedieu, Gérard
CESBIO UMR UPS-CNRS-CNES-IRD
FRANCE
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Donlon, Craig
ESA-ESTEC
NETHERLANDS
Donovan, David
KNMI
NETHERLANDS
Drinkwater, Mark
ESA
NETHERLANDS
Duesmann, Berthyl
ESA
Elena, Daganzo
ESA/ESTEC
NETHERLANDS
NETHERLANDS
Freire, Marco
ESA-ESTEC
Gonzalez Asenjo, Jose Maria
THALES ALENIA SPACE
NETHERLANDS
SPAIN
Hall, David
Astrium
UNITED KINGDOM
Hansson, Conny
ESA-ESTEC
Hartmann, Maik
Astro- und Feinwerktechnik Adlershof GmbH
NETHERLANDS
GERMANY
Haylock, Tom
RapidEye
GERMANY
Herland, Einar-Arne
Norwegian Space Centre
NORWAY
Holt, Ben
Jet Propulsion Laboratory
UNITED STATES
Humpage, Neil
University of Leicester
UNITED KINGDOM
Ingmann, Paul
ESA/ESTEC
NETHERLANDS
Johannessen, Johnny A.
NERSC
NORWAY
Johnson, Mick
Centre for EO Instrumentation
UNITED KINGDOM
Jurado, Pedro
ESA-ESTEC
Karaev, Vladimir
Institute of Applied Physics RAS
NETHERLANDS
RUSSIAN FEDERATION
Kern, Michael
ESA
NETHERLANDS
Kidd, Christopher
ESSIC/UMD & NASA/GSFC
UNITED STATES
Koeck, Charles
Astrium
FRANCE
Kolodziejczyk, Agata
Jagiellonian University
Konstanski, Harald
RapidEye
POLAND
GERMANY
Kraft, Stefan
ESA
NETHERLANDS
Lafeuille, Jerome
WMO
SWITZERLAND
Lecuyot, Arnaud
ESA
NETHERLANDS
Leigh, Roland
University of Leicester
UNITED KINGDOM
Letterio, Federico
DEIMOS Space
SPAIN
Leveque, Nicolas
Astrium Ltd
UNITED KINGDOM
López-Dekker, Paco
German Aerospace Center
GERMANY
Lorza-Pitt, Rafael
ESA
NETHERLANDS
Lynham, Timothy
Canadian Forest Service
CANADA
Marechal, Christophe
CNES
FRANCE
Martinot, Vincent
Thales Alenia Space
FRANCE
Massotti, Luca
ESA/ESTEC
NETHERLANDS
Moreau, Didier
Belgian Institute for Space Aeronomy
BELGIUM
Moreno, Jose
University of Valencia, Spain
SPAIN
Muzi, Danilo
ESA-ESTEC
Nakagawa, Keizo
Japan Aerospace Exploration Agency
NETHERLANDS
JAPAN
Nett, Herbert
ESA/ESTEC
NETHERLANDS
O'Donnell, Matt
Astrium
UNITED KINGDOM
Oertel, Dieter
Astro-und Feinwerktechnik Adlershof GmbH
GERMANY
Ording, Barend
Dutch Space
NETHERLANDS
Parrinello, Tommaso
ESA
ITALY
Pelon, Jacques
Cnrs
FRANCE
Preusse, Peter
Forschungszentrum Juelich
GERMANY
Prunet, Pascal
NOVELTIS
FRANCE
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Rast, Michael
ESA/ESRIN
ITALY
Regan, Amanda
ESA
NETHERLANDS
Remedios, John
University of Leicester
UNITED KINGDOM
Rocca, Fabio
Politecnico di Milano
ITALY
Rodriguez, Hilda
NETHERLANDS
NETHERLANDS
Roselló, Josep
ESA-ESTEC
Paris 7 University/Institute for Environmental
Sec
ESA/ESTEC
Rott, Helmut
ENVEO IT
AUSTRIA
Samsó, Laura
Elecnor Deimos Castilla La Mancha (DCM)
SPAIN
Sandnes, Runar
Norwegian Space Centre
NORWAY
Schaadt, Peter
DLR GERMAN SPACE ADMINISTRATION
GERMANY
Schmetz, Johannes
EUMETSAT
GERMANY
Scipal, Klaus
ESA
NETHERLANDS
Selig, Avri
SRON
NETHERLANDS
Shimoda, Haruhisa
JAXA
JAPAN
Silvestrin, Pierluigi
European Space Agency (ESA)
NETHERLANDS
Sobrino, JOSE A.
Universidad de Valencia
SPAIN
Steinbrecher, Ulrich
DLR
GERMANY
Stephens, Graeme
JPL
UNITED STATES
Stofflen, Ad
KNMI
Strauss, Stephan
OHB System AG
NETHERLANDS
GERMANY
Su, Bob
University of Twente
NETHERLANDS
Tanelli, Simone
Jet Propulsion Laboratory
UNITED STATES
Thapa, Nitesh
University of Turku
NEPAL
Van 'T Klooster, Kees
ESA-ESTEC
van Weele, Michiel
KNMI
NETHERLANDS
NETHERLANDS
Vane, Deborah
JPL
UNITED STATES
Verbauwhede, Michel
ESA
FRANCE
Verberne, Koen
Dutch Space
NETHERLANDS
Vicent Servera, Jorge
University of Valencia
SPAIN
Wooster, Martin
King's College London
UNITED KINGDOM
Ythier, Sylvain
NOVELTIS
FRANCE
Rosdahl, Melody
11
NETHERLANDS
APPENDIX 3 – WORKSHOP PROGRAMME
Wednesday 9th October 2013
Session 0
Welcome
Start
End
0900
0910
Welcome and Opening Remarks
V. Liebig, ESA
0910
0920
Workshop Introduction
M. Borgeaud, ESA
0920
0930
Workshop Information
A. Regan ESA-ESTEC
Session 1A
Key Science and Implementation Accomplishments from
Existing Constellations
Co-Chair
M. Borgeaud, ESA
Co-Chair
M. Drinkwater, ESA
Start
End
0930
1000
Key note: The A-Train: A Unique View of the Earth System
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G. Stephens, NASA-JPL
1000
1020
Experience of GCOM-W1 Entering A-Train
K. Nakakawa, JAXA
1020
1040
Experiences with Calipso and Future Opportunities
J. Pelon, CRNS
1040
1100
The Morning-Train: Science Overview
K. Thome, NASA-GSFC
(presented by M. Drinkwater)
Session 1B
Key Science and Implementation Accomplishments
from Existing Constellations Continued
Co-Chair
M. Borgeaud, ESA
Co-Chair
M. Drinkwater, ESA
Start
End
1130
1150
TanDEM-X Mission: Overview, Status and Outlook
U. Steinbrecher, DLR
1150
1210
COSMO-SkyMed Mission Status and Main Results
F. Covello, ASI
1210
1230
The Disaster Monitoring Constellation
P. Davies, SSTL
1230
1300
Discussion
Session 2A
Future In-Orbit Landscape: 2020 and Beyond
Co-Chair
P. Silvestrin, ESA-ESTEC
Co-Chair
A. Ciccolella, ESA-ESRIN
Start
End
1400
1405
Introductory Remarks
P. Silvestrin, ESA-ESTEC
1405
1420
ESA Earth Explorers
Mark Drinkwater,
1420
1435
Overview of Copernicus and its Evolution
A. Ciccolella, ESA-ESRIN
1435
1450
Overview of Sentinel-1
M. Davidson, ESA-ESTEC
1505
1520
Overview of Sentinel-2
K. Scipal, ESA-ESTEC
ESA-ESTEC
Session 2B
Future In-Orbit Landscape: 2020 and Beyond
Co-Chair
P. Silvestrin, ESA-ESTEC
Co-Chair
A. Ciccolella, ESA-ESRIN
Start
End
1550
1605
Overview of Sentinel-3
C. Donlon, ESA-ESTEC
1605
1625
Sentinels for atmospheric measurements
P. Ingmann, ESA-ESTEC
1625
1655
Overview of EUMETSAT Satellite Missions and Applications
J. Schmetz, EUMETSAT
Session 2C
In-Orbit Landscape 2020 and Beyond
Co-Chair
P. Silvestrin, ESA-ESTEC
Co-Chair
A. Ciccolella, ESA-ESRIN
Start
End
1700
1745
1745
1805
National Agency Perspective: Ideas for the future
•
DLR
•
JAXA
•
ASI
P. Schaadt, DLR
Vision of WMO for the space-based observing system in the
J. Lafeuille, WMO
H. Shimoda, JAXA
F. Covello, ASI
2020s
1830
Poster session
Poster Session
PAZ and TerraSAR-X Constellation, an
A. Muller, A. Kaptein, EADS Astrium
Innovative International Cooperation
F. Cicuendez Perez, F. Cerezo, Hisdesat Servicios Estrategicos
German / Canadian C/X-band Constellation
A. Kaptein, EADS Astrium,
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Experiences
B. Robertson, G. Staples MDA,
W. Geile, DLR,
W. Koppe, M. Jochum, Infoterra GmbH
Optimal Sampling in a Virtual Constellation
A. Stoffelen, KNMI
Satellite Convoy Scenario for Spaceborne MTI in
F. Letterio, S. Tonetti, Deimos Space,
Sea Clutter
S. Barbarossa, P. Di Lorenzo, F. Ceba, E. Makhoul,
A. Broquetas, Universitat Politecnica de Catalunya,
M. Maffei, Thales Alenia Space (Italy)
Redefining the Exit Criteria for the Morning and
J. Brown, a.i. solutions Inc
Afternoon Constellations
MIR-TIR Imager Systems Concepts to Observe
M. F. Buongiorno, S. Amici, C. Spinetti, M. Musacchio, M. Silvestri,
Natural and Anthropic Phenomena and
INGV
Integrate the Sentinels Constellation
Land Surface Temperature Retrieval from
J. A. Sobrino, University of Valencia
Sentinel-2 and -3 data: SEN4LST Project
A satellite formation for obtaining simultaneous
V.Karaev, M.Kanevsky, E.Meshkov, Yu.Titchenko, Institute of Applied
ocean significant wave height, mean squared
Physics, Russian Academy of Sciences,
surface slope and wind vector conditions
Ad Stoffelen, KNMI
Thursday 10th October 2013
Session 3
ESA EO Future Convoy Missions / Future Convoy
Candidate Missions
Co-Chair
U. Del Bello, ESA-ESTEC
Co-Chair
P. Bensi, ESA-ESTEC
Start
End
0830
0850
FLEX – The Benefits and Constraints of Flying in
S. Kraft, ESA-ESTEC
Formation with Sentinel-3
0850
0910
End to end mission performance simulators for EO Convoy
J. Vicent, University of Valencia
Missions: Application to FLEX/Sentinel-3 Mission
0910
0930
ESA’s Sentinel 5 Precursor – Overview on Mission and
H. Nett, ESA-ESTEC
Operations Concept
Session 4
Technological Challenges
Co-Chair
D. Vane, NASA-JPL
Co-Chair
C. M. Marechal, CNES
Start
End
1005
1030
The Cloudsat Experience and Lessons Learned
D. Vane, NASA-JPL
1030
1050
End of Mission: Planning Challenges for a Satellite in
R. Boain, NASA-JPL
Constellation
1050
1110
1110
1135
Similarities and Differences between the A-Train and the
M. Vincent, Raytheon
Proposed J-Train
(Presenting via Webex)
Discussion
Session 5A
ESA EO Convoy Study Results
•
Ocean and Ice Applications
Co-Chair
H. Rott, University of Innsbruck
Co-Chair
J. Johannessen, NERSC
Co-Chair
C. Donlon, ESA-ESTEC
Start
End
1140
1150
Session 5 Ground Rules
A. Regan, ESA-ESTEC
1150
1220
Science objectives and measurement gap analysis
J. Johannessen, NERSC
1220
1240
Convoy concepts derived to meet measurement gaps
H. Rott, University of Innsbruck
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N. Leveque, Astrium Ltd
Session 5A
ESA EO Convoy Study Results
•
Ocean and Ice Applications
Co-Chair
H. Rott, University of Innsbruck
Co-Chair
J. Johannessen, NERSC
Co-Chair
C. Donlon, ESA-ESTEC
Start
End
1400
1445
Discussion
Session 5B
ESA EO Convoy Study Results
•
Land Applications
Co-Chair
N. Humpage, University of Leicester
University of Leicester
Co-Chair
J. Remedios, University of Leicester
University of Leicester
Co-Chair
K. Scipal, ESA-ESTEC
ESA-ESTEC
N. Humpage,
Start
End
1450
1520
Science objectives and measurement gap analysis
1520
1540
Convoy concepts derived to meet measurement gaps
1540
1625
Discussion
University of Leicester
Session 5
ESA EO Convoy Study Results
•
Atmospheric Applications
Co-Chair
R. Leigh, University of Leicester
Co-Chair
A. Stoffelen, KNMI
Co-Chair
M. Cutter, SSTL
J. Langen, ESA-ESTEC
Start
End
1645
1715
Science objectives and measurement gap analysis
1715
1735
Convoy concepts derived to meet measurement gaps
1735
1820
Discussion
R. Leigh, University of Leicester
A. Stoffelen, KNMI
K. Atkinson, Astrium Ltd
Friday 11th October 2013
Session 6A
Future Concepts enabling Science and
Application Opportunities (1)
Co-Chair
M. Davidson, ESA-ESTEC
Co-Chair
F. Lopez-Dekker, DLR
Start
End
0830
0845
Science and applications from a novel ocean surface
A. Stoffelen, KNMI
vector wind constellation
0845
0900
The Role of Cloud and Precipitation Radars in Convoys
S. Tanelli, NASA-JPL
and Constellations
0900
0915
0915
0930
Bi-static Radar with Very Large Baseline: Potential
N. Pierdicca,
Applications
Sapienza University of Rome
Passive Formation Flying ATI-SAR for ocean currents
F. Lopez-Dekker, DLR
Observation – The PicoSAR Concept
0930
0945
SAOCOM+: a companion satellite to the CONAE
M. Davidson, ESA-ESTEC
SAOCOM L-band SAR mission
0945
1000
1000
1020
CryoSat-2 and Icesat-2: Overview and ideas of possible
T. Parrinello, ESA-ESRIN,
tandem operations in polar regions
A. Shepherd, University of Leeds
Future Concepts Discussion
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Session 6B
Future Concepts enabling Science and
Application Opportunities (2)
Co-Chair
J. Moreno, University of Valencia
Co-Chair
F. Buongiorno, INGV
Start
End
1040
1055
Global Frequent, High Spatial Resolution Multi-
S. Hook, NASA-JPL
spectral Thermal Infrared Data – A Future
(To be presented by M. Wooster, KCL)
Observational Gap in Earth Observation
1055
1110
Sentinel for Global Agriculture Requirements
1110
1125
Infrared Imaging Sensor Suite Mission
G. Dedieu, CESBIO UMR UPS-CNRSCNES-IRD
D. Oertel, Astro und Feinwerktechnik
GmbH
1125
1145
Session 6C
Future Concepts Discussion
Future Concepts enabling Science and
Application Opportunities (3)
Co-Chair
P. Silvestrin, ESA-ESTEC
Co-Chair
D. Fernandez, ESA-ESRIN
Start
End
1145
1200
Limb-emission sounding of atmospheric composition
M. van Weele, KNMI
and limb-nadir co-benefits
1200
1215
The Next Generation Gravity Mission Constellation
L. Massotti, ESA
Concept Studies
1215
1230
The CYGNSS Constellation (via Webex)
C. Ruf, University of Michigan
(Presented via Webex)
1230
1300
Future Concepts Discussion
Session 7
Programmatics and Data Challenges
Co-Chair
B. Hoersch, ESA-ESRIN
Co-Chair
G. Stephens, NASA-JPL
Start
End
1400
1420
Development and Implementation of International
C. Yuhas, NASA-HQ
Convoys
(To be presented by A. Regan, ESA)
C. M. Marechal, CNES
A. Kelly, NASA-GSFC
1420
1440
A-Train: What are the Keys for Success?
1440
1500
Implementation Lessons Learned from the A-Train
(To be presented by R. Boain NASAJPL)
1500
1520
The Orbital Registry
L. Newman, NASA-GSFC
(To be presented by R. Frigm, a.i.
solutions via Webex)
1520
1545
Session 8
Start
End
1545
1615
Discussion
Conclusions
Discussion
Wrap up and conclusions
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