IPPW-13 Program Abstracts - Missions Session
IPPW-13 Missions Session
Monday, June 13, 2016– 12:30 PM to 5:30 PM
Conveners: Swati Mohan Kim Reh Brandon Smith
STATUS OF INSIGHT ENTRY, DESCENT, AND LANDING
Missions
Brooke Harper
[email protected]
FOR 2018 LAUNCH OPPORTUNITY
1
EXOMARS 2016 MISSION ANALYSIS: COASTING, ENTRY, Missions
DESCENT AND LANDING
Davide Bonetti
[email protected]
2
EXOMARS SCHIAPARELLI ENTRY, DESCENT AND
LANDING SYSTEM DESIGN, DEVELOPMENT AND POSTLAUNCH STATUS
Mars 2020 Entry, Descent, and Landing Overview
Missions
Olivier Bayle
[email protected]
3
Missions
Allen Chen
[email protected]
4
HOW DOES TERRAIN RELATIVE NAVIGATION CHANGE
THE MARS 2020 ENTRY, DESCENT, AND LANDING?
Missions
David Way
[email protected]
5
TRN Performance in M2020
Missions
Swati Mohan
[email protected]
6
ESA’s Phobos Sample Return Mission
Missions
Thomas VOIRIN
[email protected]
7
THE PSYCHE MISSION: EXPLORING A METAL WORLD FOR Missions
THE FIRST TIME
David J. Lawrence
[email protected]
8
Overview of the Asteroid Redirect Mission (ARM)
Missions
Daniel D. Mazanek
[email protected]
9
ROSETTA STAR TRACKERS IN THE COMET DUST :
UNDERSTANDING AND IMPROVING THE FLIGHT
BEHAVIOUR THROUGH ON-GROUND TESTING OF THE
STR EQM WITH THE MICROSTOS
Earth Entry Vehicle Design for Comet Surface Sample
Return
Missions
Pascal Regnier
[email protected]
10
Missions
Todd White
[email protected]
11
Saturn PRobe Interior and aTmosphere Explorer
(SPRITE)
Missions
Amy A. Simon
[email protected]
12
THE BEE: A BIOSIGNATURE EXPLORER TO SAMPLE
PLUMES OF OCEAN WORLDS.
Missions
Paul Mahaffy
[email protected]
13
A DESCENT PROBE FOR EUROPA AND THE OTHER
GALILEAN MOONS OF JUPITER
Missions
Peter Wurz
[email protected]
14
ESA’s CLEO/P study: 3 potential contributions to NASA’s Missions
Multi-flyby Europa mission
Thomas VOIRIN
[email protected]
15
Global Aerial Exploration of our Sister World with the
Venus Atmospheric Maneuverable Platform (VAMP):
Mission Science Objectives and Potential Instr
DAVINCI: Deep Atmosphere Venus Investigation of
Noble Gases, Chemistry, and Imaging
Missions
Kevin H. Baines
[email protected]
16
Missions
Lori S. Glaze
[email protected]
17
THE DAVINCI AND OTHER PROBE DESCENT MODULE
AND ENGINEERING DEVELOPMENT UNITS
Missions
Michael Amato
[email protected]
18
July 13-17, Laurel MD USA.
http://ippw2016.jhuapl.edu/
1
IPPW-13 Program Abstracts - Missions Session
STATUS OF INSIGHT ENTRY, DESCENT, AND LANDING FOR 2018 LAUNCH OPPORTUNITY. B. P.
Harper1, E. D. Skulsky1, M. R. Grover1, C. E. Szalai1, D. M. Kipp1, J. A. Wertz1, E. P. Bonfiglio1, R. W. Maddock2,
1
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, 2 NASA Langley Research Center,
Hampton, VA.
Introduction: Interior exploration using Seismic
Investigations, Geodesy, and Heat Transport (InSight)
is a NASA Discovery Program mission that will send a
robotic lander to the Martian surface. It offers the opportunity to understand the formation and evolution of
terrestrial planets through two years of analyzing the
deep interior structure and processes of Mars.
Much of its design and enabling technologies are
derived from NASA's successful Mars Phoenix lander
mission from 2008, including the entry, descent, and
landing (EDL) system architecture.
The spacecraft had been on track to launch in
March 2016 until a persistent vacuum leak in its prime
science instrument prompted NASA to suspend preparations for launch. Fortunately, a proposed plan to redesign the science instrument was accepted in support
of a 2018 launch.
As the 2018 mission profile emerges, new entry
conditions and environments need to be characterized
in order to assess EDL performance. A brief overview
of the InSight EDL system design and development
challenges will be higlighted. A closer look at the significant changes between the 2016 and 2018 opportunites and the effects they have on EDL performance
metrics and margins will be presented. Results from
initial flight dynamics simulations indicate an increase
in margin for several critical metrics, most notably
peak heat rate. In fact, because of the improvements,
trade studies on entry flight path angle may be revisited to balance margin across the entire EDL phase. Current status and plans forward to facilitate the 2018
launch opportunity will be discussed.
July 13-17, Laurel MD USA.
http://ippw2016.jhuapl.edu/
2
IPPW-13 Program Abstracts - Missions Session
EXOMARS 2016 MISSION ANALYSIS: COASTING, ENTRY, DESCENT AND LANDING
D. Bonetti1 ([email protected]), G. De Zaiacomo1, G. Blanco Arnao1, J.L. Cano González1,
C. Parigini1, I. Pontijas Fuentes1, A.Pagano1
2
S. Portigliotti ([email protected]), L. Lorenzoni3 ([email protected])
1
DEIMOS Space S.L.U., Ronda de Poniente 19, Tres Cantos, 28760, Spain
2
Thales Alenia Space Italia, Italy,
3
European Space Agency (ESA), The Netherlands,
The ExoMars programme is pursued as part of a
broad cooperation between ESA and Roscosmos. This
cooperation foresees two missions within the ExoMars
programme for the 2016 and 2018 launch opportunities
to Mars.
The ExoMars 2016 mission, reaching Mars on October, 19th 2016, is led by ESA and has been successfully launched from Baikonur by the Russian launcher
Proton-M on March, 14th 2016. The mission is currently on its route to Mars in its assembly configuration
including the Trace Gas Orbiter (TGO) and the Entry,
Descent, and Landing Demonstrator (EDM, named
Schiaparelli), both supplied by ESA. The TGO scientific mission aims at investigating atmospheric trace
gases: it is expected to begin in December 2017 following an aerobraking phase, and to run for five years.
On October 16th 2016, after 7 months of interplanetary
flight and 3 days before landing on the Mars surface
(Meridiani Planum), Schiaparelli will separate from the
TGO and with its mission it will provide Europe with a
demonstration of the technology for entry, descent and
landing (EDL) on the surface of Mars with a controlled
landing orientation and touchdown velocity.
The 2018 mission of the ExoMars programme includes a carrier Module and a Mars Rover developed
by ESA, and a Descent Module including a Surface
Platform developed by Roscosmos. The project is is
currently in Phase C/D and it is scheduled to be
launched by Proton in 2018.
DEIMOS Space has been involved in the Exomars
Programme (2016 and 2018 missions) since 2004
providing more than 10 years of technical activities in
the areas of End to End (from launch to landing) Mission Engineering and GNC.
In autumn 2015, the backup launch window of
2016 mission has been activated postponing the launch
to the period 14th-25th March 2016, replacing the
nominal launch window originally set in January 2016.
This paper presents the Mission Engineering activities performed by DEIMOS Space in support to Thales
Alenia Space Italia, acting as prime contractor for the
ExoMars2016 Mission. Support is dedicated to the
analysis of the Schiaparelli mission, from separation
from the TGO to landing, for the March 2016 launch.
The analyses presented cover the impact of the switch
July 13-17, Laurel MD USA.
to the back-up launch window and initial flight predictions for the current launch day, from multiple aspects:
system margins identification through local entry corridors analyses and 3DoF/6DoF End to End Monte Carlo
campaigns, verification of nominal ESA trajectories
and separation maneuver optimization for landing site
targeting, EDM aerodynamic database inspection and
Flying Qualities Analysis, and TGO-Schiaparelli geometric visibility analyses.
All the analyses rely on DEIMOS Space state of the
art tools for Mission Engineering (PETbox, Planetary
Entry Toolbox [1] and LOTNAV, Low-Thrust Interplanetary Navigation Tool) whose results and design
methodology for Atmospheric Flight have been recently Flight Qualified through the successful ESA IXV
mission [2], in which DEIMOS Space was responsible
of the Mission Analysis and re-entry Guidance and
Control.
References:
[1] Bonetti D. et al (2016) “PETbox: Flight Qualified Tools for Atmospheric Flight”, 6th ICATT.
[2] Bonetti D. et al (2015) “IXV Mission Analysis
and Flight Mechanics: from design to postflight”,
AIDAA 2015.
http://ippw2016.jhuapl.edu/
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IPPW-13 Program Abstracts - Missions Session
EXOMARS SCHIAPARELLI ENTRY, DESCENT AND LANDING SYSTEM DESIGN, DEVELOPMENT
AND POST-LAUNCH STATUS
O. Bayle1, L. Lorenzoni1, T. Blancquaert1, S. Langlois1, T, Walloschek1, S. Portigliotti2 and G. Passarelli2
1
European Space Agency (ESTEC, Noordwijk, The Netherlands)
2
Thales Alenia Space Italy (Torino, Italy).
The ExoMars 2016 Mission was launched on 14
March 2016 and constitutes the first mission of the
ESA-Roscosmos joint programme for Mars exploration. The ExoMars 2016 mission includes the Trace
Gas Orbiter (TGO) and the Schiaparelli module, which
shall provide a demonstration of key technologies required to safely land a payload on the surface of Mars:
- Heat Shield
- Parachute System
- Guidance, Navigation and Control System
- Doppler Radar System for ground relative altitude and relative velocity measurement
- Liquid Propulsion System for attitude control
and final braking
- Crushable material for impact loads attenuation
Schiaparelli (also called EDL Demonstrator Module – EDM) includes a package of sensors that will
monitor the performance of the EDL subsystems in
order to maximise the lessons learnt from this technology demonstration mission in preparation to the subsequent mission that shall bring the ExoMars Rover to
the Mars surface. In order to guarantee the return of the
data gathered during the EDL, a robust communication
strategy has been established between Schiaparelli and
the ESA and NASA orbiters, which will allow the return of the complete data set before the end of Schiaparelli short lifetime on Mars surface.
scribe the completion of the Heat Shield, which took
place only a few days before the launch.
The paper provides also the status of the ExoMars
2016 mission during its course to Mars and the description of the next steps of the mission. Schiaparelli
will reach Mars on 19 October 2016, and will land in
Meridiani Planum.
Finally, the papers gives an outlook of the Entry,
Descent and Landing systems that will be used for the
following ExoMars Rover and Surface Platform mission. The EDL systems used for that mission will
shared between ESA and Roscosmos, ESA providing
the Parachute System, the Guidance and Navigation
system, the Doppler Radar System, the Inertial Measurement Unit, the Data Handling unit and the TT&C
system.
Although designed to demonstrate EDL technologies, Schiaparelli also includes a science package that
will operate on the surface of Mars for a short duration
after landing, to perform meteorological measurements
and characterize the Martian environment during dust
storms period.
The paper provides an overview of the EDM mission and design and describes the last integration and
test activities that have already been carried out before
the launch. In particular, the paper describes the last
tests performed on the integrated subsystems (parachute system, propulsion system, RADAR system) and
on Schiaparelli flight model. An outlook of the last
integration activities is presented, in particular to de-
July 13-17, Laurel MD USA.
Figure 1 – Schiaparelli and TGO before encapsulation in Proton launcher fairing
http://ippw2016.jhuapl.edu/
4
IPPW-13 Program Abstracts - Missions Session
MARS 2020 ENTRY, DESCENT, AND LANDING OVERVIEW. A. Chen1, P. Brugarolas1, E. Hines1, A. Johnson1, R. Otero1, A. Stehura1, G. Villar1, D. Way2. 1Jet Propulsion Laboratory, California Institute of Technology
(Pasadena, CA, 91009, [email protected]), 2NASA Langley Research Center (Hampton, VA 23681, [email protected])
Abstract: Building upon the success of Curiosity’s
landing and surface mission, the Mars 2020 project is a
flagship-class science mission intended to address key
questions about the potential for life on Mars and collect samples for possible return to Earth [1]. The mission will also gather knowledge and demonstrate technologies that address key challenges for future human
expeditions to Mars. Based on the highly successful
entry, descent, and landing (EDL) architecture from
the Mars Science Laboratory (MSL) mission [2], Mars
2020 will launch in July of 2020 and land on Mars in
February of 2021.
The mission takes advantage of the favorable 2020
launch/arrival opportunity; this enables the delivery of
a larger, heavier, and more capable rover to wider variety of potential landing sites. While Mars 2020 inherits most of its EDL architecture, software, and hardware from MSL, a small number of changes have been
made to correct deficiencies, improve performance,
and increase the overall robustness of the system. The
most significant of these changes is the recent addition
to the baseline of a Terrain Relative Navigation (TRN)
system, which will allow the vehicle to safely land at
much more rugged and hazardous landing sites.
This paper presents an overview of the Mars 2020
EDL design and discusses the changes made as the
project enters Phase C. Additionally, the paper also
summarizes the Mars 2020 landing site safety assessment that is in progress in preparation for the next
landing site selection workshop.
References:
[1] Mustard, J., et al. (2013) “Report of the Mars
2020 Science Definition Team,” Tech. rep., Mars Exploration Program Analysis Group (MEPAG).
[2] Steltzner, A. (2013) “Mars Science Laboratory
Entry, Descent, and Landing System Overview”, AAS
13-236.
July 13-17, Laurel MD USA.
http://ippw2016.jhuapl.edu/
5
IPPW-13 Program Abstracts - Missions Session
HOW DOES TERRAIN RELATIVE NAVIGATION CHANGE THE MARS 2020 ENTRY, DESCENT,
AND LANDING? D.W. Way1, S. Dutta2, A. Chen3, and P. Brugarolas4. 1NASA Langley Research Center (Hampton, VA 23681, [email protected]), 2NASA Langley Research Center (Hampton, VA 23681,
[email protected]), 3Jet Propulsion Laboratory (Pasadena, CA, 91009, [email protected]), and 4Jet
Propulsion Laboratory (Pasadena, CA, 91009, [email protected]).
Abstract: The Mars 2020 project is a flagshipclass science mission to land the next robotic explorer
on Mars. With a state-of-the-art suite of scientific instruments, the new Curiosity-class rover will conduct a
search for the evidence of past life, and for the first
time, collect rock and soil samples for possible return
to Earth [1]. Based on the highly successful Mars Science Laboratory (MSL) Entry, Descent, and Landing
(EDL) architecture and the Sky Crane landing system
[2], the new mission will launch in July of 2020 and
will reach Mars in February 2021.
While Mars 2020 inherits most of its EDL architecture, software, and hardware from MSL, a few minor
adjustments and improvements have been made to the
EDL system design to either correct known issues
from MSL or to improve the overall robustness of the
system. The most significant of these changes is the
recent addition to the baseline of a Terrain Relative
Navigation (TRN) system, which will allow the vehicle to safely land at much more rugged and hazardous
landing sites.
This TRN system fits nicely within the heritage
MSL architecture by taking advantage of the postseparation propulsive divert maneuver performed to
minimize the backshell re-contact risk. The TRN system consists of two main sub-systems: the Lander Vision System (LVS) and the Safe Target Selection
(STS). The LVS provides terrain-relative localization
of the vehicle position by taking real-time camera images while descending on parachute. These images are
processed and co-registered to an on-board map, all on
a dedicated compute element. This localized solution
is then used within STS to determine a safe landing
site that is reachable within the constraints of the propulsive divert.
The presence of the TRN system allows the science
community to propose landing sites that would otherwise be considered too risky. This alters slightly the
careful balance of EDL risks inherent in the MSL system. This paper will focus on the minor adjustments
made to the MSL EDL system to rebalance these risks
in the presence of TRN.
[2] Steltzner, A. (2013) “Mars Science Laboratory
Entry, Descent, and Landing System Overview”, AAS
13-236. [3] Way, D. W., Davis, J. L, and Shidner, J. D.
(2013) “Assessment of the Mars Science Laboratory
Entry, Descent, and Landing Simulation”, AAS 13420. [4] Way, D. W. (2013) “Preliminary Assessment
of the Mars Science Laboratory Entry, Descent, and
Landing Simulation”, IEEE-2013-2755.
References:
[1] Mustard, J., et al. (2013) “Report of the Mars
2020 Science Definition Team,” Tech. rep., Mars Exploration Program Analysis Group (MEPAG).
July 13-17, Laurel MD USA.
http://ippw2016.jhuapl.edu/
6
IPPW-13 Program Abstracts - Missions Session
TRN Performance in M2020. S. Mohan1, P. Brugarolas1, D. Way2, N. Trawny1, A. Stehura1, S. Dutta2, J. Montogmery1, A. Johnson1, A. Chen1 1NASA Jet Propulsion Laboratory, Calilfornia Institute of Technology (4800 Oak
Grove Drive, Pasadena CA 91109), 2NASA Langley Research Center (8 Lindbergh Way, Hampton, VA 23681).
Abstract:
The Terrain Relative Navigation (TRN) system is
an enabling Entry, Descent, and Landing
(EDL) technology slated for inclusion in the Mars 2020
mission [1]. TRN provides real-time, autonomous, terrain-relative position determination and generates a
landing target based on a priori knowledge of hazards.
TRN is composed of the Lander Vision System (LVS)
[2] and the Safe Target Selection (STS) algorithm [3].
The LVS generates a map-relative localization solution
by fusing measurements from a visible-wavelength
camera and an inertial measurement unit using the Map
Relative Localization (MRL) algorithm operating on a
high-performance compute element. Updated state
knowledge is provided to the spacecraft navigation
filter, which uses the STS algorithm to direct a divert
maneuver away from known hazards within an onboard
map.
The needs of Mars 2020 require TRN to have sufficient horizontal position accuracy to avoid hazards of
60m or less. The nominal performance reserves margin on this and sub-allocates the remaining to three
parts. The three parts are: the targetting accuracy based
on the LVS map-relative localization [4], the
knowledge error from the time of localization to the
ground, and the control error of the vehicle with respect to the reference trajectory. A reduced case performance is also flowed down with no margin for fault
conditions that sub-allocates the entire 60m to the three
parts. This paper presents the error budget structure
and sub-allocations for both the nominal and reduced
cases. Preliminary design results are presented that
show current best estimate performance of 31m, more
than 30% to the 60m requirement.
Landing Sites on Mars, AIAA SciTech, San Diego CA
2016.
CL#16-1172
[1] Allen Chen et al. (2015) 2015 Update: Mars
2020 Entry, Descent, and Landing System Overview,
IPPW12 Presentation #2104.
[2] Aaron Stehura et al. (2015) The Future of Landing: Terrain Relative Navigation From Prototype to
Mars 2020, IPPW12 Presentation #3104.
[3] Paul Brugarolas et al. (2015) On-Board Terrain Relative Guidance-Target Selection for the Mars
2020 Mission, IPPW12 Presentation #3105.
[4] Andrew Johnson et al. Design and Analysis of
Map Relative Localization for Access to Hazardous
July 13-17, Laurel MD USA.
http://ippw2016.jhuapl.edu/
7
IPPW-13 Program Abstracts - Missions Session
ESA’s Phobos Sample Return Mission. T. Voirin1, J. Larranaga2, J. Romstedt1, D. Koschny1, D. Rebuffat1
1
ESA-ESTEC ([email protected]), 2AURORA B.V. for ESA/ESTEC ([email protected]).
Introduction: ESA has just concluded a 1 year
phase A system study for a Phobos Sample Return
Mission (PhSR). The main scientific goal of PhSR is to
discriminate between the various candidate theories
explaining Phobos formation : impact, co-formation
and capture. Meeting this goal requires bringing back
to Earth at least 100g of Phobos regolith for extensive
laboratory analyses. This is the main mission requirement for PhSR.
The PhSR S/C has a total mass at launch of ~ 5
tons and is a stack composed of 4 elements : the Propulsion Module, the Landing Module (carrying the
scientific payload), the Earth Return Vehicle, itself
carrying the Earth Re-entry Capsule (ERC) in which
the sample will be encapsulated. The S/C includes a
comprehensive payload composed of several remote
sensing instruments (Wide Angle Camera, Narrow
angle Camera, Mid-IR and Near IR spectrometers),
used for Phobos characterization, and a surface package composed of a Stereocamera (STCAM), a Closeup imager (CLUPI), and the Sample Acquisition and
Containment System in charge of collecting, verifying,
sealing and inserting the sample in the ERC.
Mission Overview
The PhSR mission foresees a launch in 2025 on the
Ariane 5 or 6 launcher, covering a total mission duration between 3 and 5 years, depending on the selected
launcher. After Mars Orbit Insertion, a series of manoeuvres are performed to phase the orbit with Phobos
orbit around Mars. The Propulsion Module is jettisoned afterwards. A 3-months phase of Phobos global
characterization follows, using a quasi-satellite orbit
(QSO) around Phobos, which allows mapping of more
than 50% of its surface at 3m spatial resolution. During
this phase, on top of the scientific observation, extensive radio-tracking orbit determination will be performed, supported by the acquisition of navigation
images and the build-up of a landmarks database. This
allows to reach unprecedented accuracy in the
knowledge of Phobos gravity field and ephemeris, and
of the knowledge of S/C position.
Based on the acquired images, 3 candidate landing
sites will be selected by the ground team, involving
scientists and engineers. The S/C will then perform one
low altitude flyby (5 km) over each candidate landing
site to allow for local characterization at 15 cm spatial
resolution. These observations will allow the ground
team to select the highest priority landing site among
the three candidates.
July 13-17, Laurel MD USA.
A transfer manoeuvre then brings the S/C from the
QSO to a “gate” located 5 to 10 km above the selected
landing site, and from where a closed-loop controlled
descent follows. The last 50m of the descent are performed in free-fall to limit the contamination of the
sampling area by the propulsion system. The landing
occurs at less than 1 m/s vertical velocity, and with a
dispersion of 50m (at 95% confidence). Due to the low
gravity of Phobos, hold-down thrusters are used during
touch down to ensure the S/C stability on the surface.
Once on the surface, the sampling area reachable
by the robotic arm is imaged by STCAM, providing a
1 cm spatial resolution. This allows the science team to
pre-select 3 candidate sampling points within the
reachable area. A CLUPI image of each of the candidate sampling points is then acquired, providing 300
µm spatial resolution. This resolution allows the scientists to select the highest priority sampling point (ensuring for instance diverse types of grains,e.g. pebbles
are present within the sampled area). In total, the decision-making process including S/C operations for the
selected sampling point can take up to a few weeks.
Once selected, a complete CLUPI scan around the
sampling point is performed at 100 µm spatial resolution. This operation will be repeated after the sampling
and will allow, by observing the macroscopic deformation caused by the sampling procedure on the surroundings, to infer properties on the Phobos soil structure. The sampling itself will be performed by the
sampling tool, of either a corer-type or a rotary brush.
After the sampling verification, the sample will be
sealed and inserted into the ERC.
After up to 1 month on the Phobos surface, the liftoff of the ERV will be triggered. Ultimately, the ERV
is injected into a Mars-Earth transfer interplanetary
orbit. The ERC will be released shortly before arrival
at Earth vicinity to perform a direct entry into Earth
atmosphere. To be representative of a potential Mars
Sample Return mission capsule, it has been decided
that the ERC would not have any parachute system,
and would perform a hard landing in Woomera (Australia). The impact energy is absorbed by a crushable
material, which allows the sample to remain within
acceptable g-load levels (<2,000g). The ERC will then
be localized by a beacon, retrieved and transferred to a
Sample Receiving Facility.
Note that an alternative PhSR scenario in cooperation with Roscosmos has been studied during the phase
A, but this paper focuses on the ESA-only scenario.
http://ippw2016.jhuapl.edu/
8
IPPW-13 Program Abstracts - Missions Session
THE PSYCHE MISSION: EXPLORING A METAL WORLD FOR THE FIRST TIME. L.T. Elkins-Tanton1,
E. Asphaug2, J. Bell2, D. Bercovici3, B.G. Bills4, R.P. Binzel5, W.F. Bottke6, J. Goldsten7, R. Jaumann8, I. Jun4, D.J.
Lawrence7, S. Marchi6, D. Oh4, R. Park4, P.N. Peplowski7, C.A. Polanskey4, T.H. Prettyman10, C.A. Raymond4, C.T.
Russell11, B.P. Weiss5, D.D. Wenkert4, M. Wieczorek9, M.T. Zuber5, 1School of Earth and Space Exploration, Arizona State University, 781 Terrace Rd., Tempe AZ 85287, [email protected], 2ASU, 3Yale, 4JPL, 5MIT, 6SwRI,
7
APL, 8DLR, 9IPGP, 10PSI, 11UCLA.
Introduction: Psyche is a Discovery-class mission, selected for a Step 2 concept study, to investigate
an exposed metal planetary core. Our target is the large
asteroid Psyche (~240 x 185 x 145 km) that orbits at 3
AU. It is made almost entirely of Fe-Ni metal, as indicated by:
• High radar albedo of 0.42 [1]
• Thermal inertia of ~120 J m-2 S-0.5 K-1 [2] (Ceres,
Pallas, Vesta, Lutetia are all 5 to 30 J m-2 S-0.5 K-1)
• Density estimates of 6,980 ± 580 kg m-3 [3], 6,490
• ± 2,940 kg m-3 [4, 5], and 7,600 ± 3,000 kg m-3 [6].
A 0.9 µm absorption feature suggests 10% of Psyche’s surface is high-magnesian orthopyroxene [7].
Psyche may be:
• A larger planetesimal’s exposed core, once molten,
that solidified either inside-out or outside-in, and is
now either intact or now broken into a rubble pile;
• Not a core, but instead highly reduced, primordial
metal-rich materials that accreted, but never melted.
or measure the core directly. Psyche offers a unique
window into the violent history of collisions and accretion that created the planets and their cores.
Meteorite geochronology reveals that metal cores
formed within the first half million years [8]. Meteorites also reveal that many differentiated bodies, including iron meteorite parent bodies, produced magnetic
dynamos [9-11]. High-energy impacts were ubiquitous
in the early solar system, so cores likely formed and
reformed repeatedly.
Models show that there were many destructive “hit
and run” impacts that could strip the silicate mantle
from differentiated bodies, leaving an exposed metal
core. This is the leading hypothesis for Psyche’s formation (Fig. 1). Psyche is the only asteroid that will
yield substantial information about metal cores (other
metallic asteroids are far smaller and not roughly
spherical).
The Psyche investigation has three broad goals:
1. Understand a previously unexplored building block of planet formation: iron cores.
2. Look inside the terrestrial planets, including Earth, by directly examining the interior of a differentiated
body, which otherwise could not be
seen.
3. Explore a new type of world. For
the first time, examine a world made
not of rock, ice, or gas, but of metal.
Psyche mission objectives:
A. Determine whether Psyche is a core,
or if it is unmelted material.
B. Determine the relative ages of regions of its surface.
C. Determine whether small metal bodies incorporate the same light elements
as are expected in the Earth’s highFig 1: Discovery class investigation of Psyche. The mission plan inpressure core.
cludes solar electric cruise, arrival at Psyche in 2026, and 12 months
D. Determine whether Psyche was
of science operations.
formed under conditions more oxidizing or more reducing than Earth’s core.
Hit-and-run collisions could create Psyche: DeE.
Characterize
Psyche’s topography.
spite living on this planet and being able to study it
We
will
meet
these
objectives by examining Psyche
more closely than any other, we continue to revise our
with
three
high
heritage
instruments and radio science:
models of Earth’s core, in part because we cannot see
July 13-17, Laurel MD USA.
http://ippw2016.jhuapl.edu/
9
IPPW-13 Program Abstracts - Missions Session
1. Multispectral imagers (MSL Mastcam heritage)
with clear and seven color filters provide surface geology, composition, and topographic information [12].
2. A gamma-ray and neutron spectrometer
(MESSENGER heritage) determines the elemental
composition for key elements (e.g., Fe, Ni, Si, and K)
as well as compositional heterogeneity across Psyche’s
surface [13, 14].
3. Dual fluxgate magnetometers characterize the
magnetic field [15].
4. Radio science will map Psyche’s gravity field
using the X-band telecomm system.
Synthesis and Expected Outcomes: If our magnetometer detects a coherent dipolar field, then Psyche
had a core magnetic dynamo and solidified outside-in,
allowing the cold solid exterior to record the magnetic
field [16]. We would then expect to find Ni content of
~4 wt% (or slightly lower if diluted with other material), consistent with the first solidifying metal in a fractionating core. Nickel of 6–12 wt% indicates the surface was the last material to solidify and thus the core
solidified inside-out. We would expect no remanent
magnetic field, since there would have been no cool
surface material to record the field while the dynamo
was working (Fig. 2).
If we find very low nickel content, and no coherent
magnetic field, then we may arrive at perhaps the most
exciting hypothesis: Psyche never melted, but consists
of highly reduced, primordial metal. This hypothesis
would be further supported by the discovery of no
mantle silicates, but instead reduced silicates mixed on
a small scale throughout the surface. The likeliest place
for such material to exist is closest to the Sun in the
early disk, where temperatures are very hot (reducing)
and light elements are volatilized away, leaving heavy
elements and metals. This outcome would support the
hypothesis of Bottke et al. [17], that such bodies were
injected into the asteroid belt from the innermost solar
system. This kind of migration has been little considered.
If we find a coherent dipolar magnetic field and either higher or lower average surface nickel content,
then we have found something unexpected based on
existing models for small core formation.
If we discover that Psyche has a magnetic field,
then we will have detected in situ magnetization at an
asteroid for the first time. The increasing evidence that
some planetesimals had magnetic dynamos requires
that they had convecting metallic cores, but our understanding of the ways they solidify makes modeling
their dynamos difficult. If Psyche was a core and solidified from the outside inward, it is an analog for Mercury’s and Ganymede’s cores in the present day, which
may be solidifying this way [18]. This unexpected process could be observed on Psyche as can never be done
on Mercury. Solidification inside out, in contrast, parallels the Earth’s core.
References: [1] Shepard et al. (2010) Icarus, 208,
221. [2] Matter et al. (2013) Icarus, 226, 419. [3]
Kuzmanoski & Koraccević (2002) Astron. & Astrophys., 395, L17. [4] Baer et al. (2011) Astronom. J,
141, 1. [5] Lupishko (2006) Solar Sys. Res., 40, 214.
[6] Shepard et al. (2008) Icarus, 195, 184. [7] Hardersen et al. (2005) Icarus, 175, 141. [8] Scherstén, et al.
(2006) EPSL, 241, 530. [9] Tarduno et al. (2012) Science, 338, 939; [10] Elkins Tanton et al. (2011) EPSL,
305, 1. [11] Bryson et al. AGU abstract (2015). [12]
Bell et al., 47th LPSC, Abstract #1366 (2016). [13]
Peplowski et al., 47th LPSC, Abstract #1394 (2016).
[14] Lawrence et al., 47th LPSC, Abstract #1622
(2016). [15] Weiss et al., 47th LPSC, Abstract #1661
(2016). [16] Scheinberg et al., this LPSC (2016). [17]
Bottke et al. (2006) Nature, 439, 821. [18] Hauck et al.
(2013) JGR, 118, 1204.
Fig. 2. Instrument measurements allow hypothesis discrimination. Ni content and magnetic field shows both measurement margin
outside of expected models and utility of multiple instruments addressing the same hypotheses. Ni below 4 wt% is not detectable by our
instruments, but we will use magnetic field
measurement, silicate domain size, and oxidation state to discriminate between the two
low-Ni models.
July 13-17, Laurel MD USA.
http://ippw2016.jhuapl.edu/
10
IPPW-13 Program Abstracts - Missions Session
OVERVIEW OF THE ASTEROID REDIRECT MISSION (ARM). D. D. Mazanek1, P. A. Abell2, D. M.
Reeves1, P. W. Chodas3, M. M. Gates4, R. L. Ticker4, and L. N. Johnson5, 1Systems Analysis and Concepts Directorate, NASA Langley Research Center ([email protected]), 2Astromaterials Research and Exploration
Science Division, NASA Johnson Space Center, 3Center for Near-Earth Object Studies, Jet Propulsion Laboratory,
4
Human Exploration and Operations Mission Directorate, NASA Headquarters, 5Planetary Defense Coordination
Office, NASA Headquarters.
Background: To achieve its horizon goal of sending humans to Mars, the National Aeronautics and
Space Administration (NASA) plans to proceed in a
series of incrementally more complex human spaceflight missions. Today, human flight extends only to
Low-Earth Orbit (LEO), and should problems arise
during a mission, the crew can return to Earth in a matter of hours. The next step comprises cis-lunar missions
which provide a “proving ground” for the testing of
systems and operations while still accommodating an
emergency return path to the Earth of several days. Cislunar proving ground mission experience will be essential for more ambitious human missions beyond the
Earth-Moon system, which will require months, or
even years of transit time. In addition, NASA has been
given a Grand Challenge to “find all asteroid threats to
human populations and know what to do about them.”
Obtaining knowledge of asteroid physical properties
and performing asteroid deflection technique demonstrations for planetary defense provide much needed
information to address the mitigation of potentials asteroid impacts with Earth.
Mission Description: NASA’s Asteroid Redirect
Mission (ARM) is a capability demonstration mission
that combines robotic and crewed segments to develop,
test, and utilize a number of key capabilities that will
be needed for future exploration of Mars and other
Solar System destinations, as well as providing other
broader benefits. ARM consists of two mission segments: 1) the Asteroid Redirect Robotic Mission
(ARRM), the first robotic mission to visit a large
(greater than ~100 m diameter) near-Earth asteroid
(NEA), collect a multi-ton boulder from its surface
along with regolith samples [1], demonstrate a planetary defense technique known as the Enhanced Gravity
Tractor (EGT) [2], and return the asteroidal material to
a stable orbit around the Moon; and 2) the Asteroid
Redirect Crewed Mission (ARCM), in which astronauts will take the Orion capsule to rendezvous and
dock with the robotic vehicle, conduct multiple extravehicular activities to explore the boulder, and return to
Earth with samples. NASA’s proposed ARM concept
would leverage several key ongoing activities in human
exploration, space technology, and planetary defense.
The ARRM is planned to launch at the end of 2021,
which would likely place the ARCM in 2026.
July 13-17, Laurel MD USA.
Mission Objectives: The Asteroid Redirect Mission is designed to address the need for flight experience in cis-lunar space and provide opportunities for
testing the systems, technologies, and capabilities that
will be required for future human operations in deep
space. The highest priority objective of ARM is to
conduct a human spaceflight mission involving inspace interaction with a natural object, in order to provide the systems and operational experience that will
be required for eventual human exploration of the Mars
system, including the Martian moons Phobos and Deimos. The second primary objective of ARM is the development of a high-power Solar Electric Propulsion
(SEP) vehicle, and the demonstration that it can operate for many years in interplanetary space, which is
critical for deep-space exploration missions. By transferring the multi-ton asteroid boulder to lunar vicinity,
ARRM will demonstrate the ability for SEP-based
spacecraft to transport massive objects such as crew
habitats, landers, or interplanetary cargo. ARRM will
also conduct proximity operations with a natural space
object in a low-gravity environment. Using sensors and
high-speed processing, the ARRM spacecraft will survey the asteroid surface, navigate to the selected landing site and boulder, and autonomously capture the
target boulder using dexterous robotics. These autonomy and dexterous robotics capabilities may be employed for future Mars logistics and in-situ resource
utilization, as well as science sample return. The
ARCM provides a focus for the early flights of the
Orion program, which will take place before the infrastructure for more ambitious flights will be available.
Astronauts will participate in the scientific in-space
investigation of nearly pristine asteroid material, at
most only minimally altered by the capture process.
The ARCM will provide the opportunity for human
explorers to work in space with asteroid material, testing the activities that would be performed and tools
that would be needed for later exploration of primitive
body surfaces in deep space. The operational experience would be gained close to our home planet, making
it a significantly more affordable approach to obtaining
this experience. The combined objectives of human
exploration and planetary defense, along with the
knowledge gained and operational experience that will
benefit the scientific and asteroidal resources communities, provide a broad-based rationale for the ARM.
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11
IPPW-13 Program Abstracts - Missions Session
Following completion of joint ARRM-ARCM operations, the ARRM spacecraft could possibly be refueled
and reused as an infrastructure element such as spacebased “tug” or power source, or to conduct additional
small body exploration.
Target Asteroid Candidates: NASA has identified the NEA (341843) 2008 EV5 as the reference target for the ARRM, but is also carrying three other
NEAs as potential options [(25143) Itokawa, (162173)
Ryugu, and (101955) Bennu]. Additionally, the nearEarth object observations program continues to search
for potential candidates. The final target selection for
the ARRM will be made approximately a year before
launch, but there is a strong recommendation from the
scientific and resource utilization communities that the
ARM target be volatile and organic rich. Three of the
current candidates are carbonaceous NEAs. Specifically, the ARRM reference target, 2008 EV5 is a carbonaceous (C-type) asteroid that has been remotely characterized (via visual, infrared, and radar wavelengths), is
believed to be hydrated, and provides significant return
mass potential (with evidence for boulders on the surface greater than 20 metric tons). It also has an advantage in that the orbital dynamics of the NEA fall
within the current baseline mission timeline of five
years between the launch of the ARRM and the launch
of the ARCM to allow for the round trip return of the
robotic vehicle to cis-lunar space. Therefore, NEA
2008 EV5 provides a valid target that can be used to
help with formulation and development efforts.
Input to ARM and Future Plans: In the fall of
2015, NASA established the Formulation Assessment
and Support Team (FAST), which was chartered by
NASA to provide timely inputs for mission requirement formulation in support of the ARRM Requirements Closure Technical Interchange Meeting (TIM) in
mid-December of 2015, to assist in developing an initial list of potential mission investigations, and to provide input on potential hosted payloads and partnerships that could be provided by domestic and international partners. Expertise from the science, engineering, and technology communities was represented by
exploring lines of inquiry related to key characteristics
of the ARRM reference target asteroid (2008 EV5) for
engineering design purposes. As of December 2015,
the FAST has been formally retired and the FAST final
report was publically released in February of 2016 [3].
However, plans have been made to stand up an ARM
Investigation Team (IT), which is expected be formed
in 2016. The multidisciplinary IT will assist with the
definition and support of mission investigations, support ARM program-level and project-level functions,
provide technical expertise, and support NASA Headquarters interactions with the technical communities
July 13-17, Laurel MD USA.
through mission formulation, mission design and vehicle development, and mission implementation. Addtionally, NASA plans to provide opportunities for additional contributed hardware payloads and associated
investigations to be included as part of the ARRM.
References: [1] Mazanek D. D., Merrill R. G.,
Belbin S. P., Reeves D. M., Earle K. D., Naasz B. J.,
and Abell P. A. (2014) Asteroid Redirect Robotic Mission: robotic boulder capture option overview.
AIAA/AAS Astrodynamics Spec. Conf., San Diego.
[2] Mazanek, D. D., Reeves, D., Hopkins, J., Wade,
D., Tantardini, M., and Shen, H. (2015) “Enhanced
Gravity Tractor Technique for Planetary Defense,” 4th
IAA Planetary Defense Conference − PDC 2015, Frascati, Roma, Italy. [3] Mazanek, D. D., et al. (2016).
“Asteroid Redirect Mission (ARM) Formulation Assessment and Support Team (FAST) Final Report.”
NASA/TM–2016-219011.
http://ippw2016.jhuapl.edu/
12
IPPW-13 Program Abstracts - Missions Session
ROSETTA STAR TRACKERS IN THE COMET DUST : UNDERSTANDING AND IMPROVING THE
FLIGHT BEHAVIOUR THROUGH ON-GROUND TESTING OF THE STR EQM WITH THE
MICROSTOS OPTICAL STIMULATOR.
P. Regnier1, P. Vidal1 and S. Lodiot2, J-L Pellon-Bailon2, 1Airbus Defence & Space ([email protected],
[email protected],), 2ESOC ([email protected], [email protected]).
Introduction: The Rosetta probe reached its destination comet Churyumov-Gerasimenko in spring
2014 after a ten-year long journey through outer space.
After releasing the Philae lander on November 12th of
that year, the European Space Operations Center
(ESOC) commanded the Rosetta orbiter to lower its
orbit to perform low altitude fly-bys for enhanced science. However at that time the comet outgassing activity started to become burdensome to the spacecraft star
trackers and the Attitude and Orbit Control System
(AOCS) attitude estimation function, up to the point of
triggering a safe mode in march 2015.
Then, as anticipated, the situation did not improve
towards the comet perihelion passage in august 2015,
forcing ground operators to retreat the Rosetta orbiter
further away from the comet in order to preserve its
precious attitude estimation function from the hazardous comet dust environment.
As the designer and manufacturer of the Rosetta
orbiter, Airbus Defence and Space proposed to ESOC
an original engineering support and in-flight expertise
trying to better characterize and potentially improve
the in-flight behaviour, through an on-ground testing
campaign of the 15-year old Rosetta Star Tracker Engineering and Qualification Model (EQM) connected
to the spacecraft EQM at ESOC, with a specially
adapted in-house Optical Stimulator named the microSTOS.
This presentation will first describe the observed attitude estimation in-flight behavior, then present the
proposed AOCS SW improvements before detailing
the Rosetta EQM test phase carried out at ESOC end
2015, and the obtained results.
Comet dust effects on Star Trackers and attitude estimation : although the Rosetta star tracker
software was developed from the beginning with special measures to improve the robustness of the lost-inspace acquisition and tracking modes to comet dust
environment, actual conditions encountered at low altitudes (illustrated in the attached STR CCD image)
have generated STR anomalies such as transient locking on false stars resulting in Failure Detection Isolation and Recovery (FDIR) actions and safe mode triggering. Attitude off-pointing was also observed as a
consequence of transient locking on false stars.
July 13-17, Laurel MD USA.
Proposed improvements and on-ground tests :
The AOCS SW improvements proposed by Airbus
Defence and Space consisted in a tightening of the gyro-stellar innovation threshold based on empirical inflight TM results, together with an enlarging of the
corresponding FDIR surveillance, in order to better
isolate the attitude estimation function from false stars
locking at STR level. However the limited Rosetta TM
observability and the limitations in the available 15year old simulation test benches did not allow to gain
enough confidence in the adequation of these proposed
SW modifications. Therefore Airbus DS proposed to
use a powerful optical stimulator (the in-house microSTOS) in front of the Rosetta Star Tracker EQM to
exercise the clones of the real in-flight STR and AOCS
SW in order to try to reproduce the in-flight behavior
and validate the efficiency and safety of the proposed
SW modifications. This raised many challenges such as
reviving a STR optical head HW unit never used since
15 years, by-passing Rosetta EQM simulation limitations, adapting the microSTOS SW to add the simulation of dust and the microSTOS HW to fit with the old
STR HW, and various iterations necessary to achieve
valuable results, notably locking the STR on false stars
before losing tracking.
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13
IPPW-13 Program Abstracts - Missions Session
MicroSOS installation on the Rosetta
EQM Optical Head
Test Results and Conclusions : At the end, the inflight complex behavior could be reproduced, especially the FDIR triggering and the attitude off-pointing as
observed in march 2015. Simulations done with the
proposed SW modifications exhibited no FDIR triggering and much less attitude off-pointing, showing a potential benefit for more in-flight robustness in the comet dust environment. However since the testing has
been made, the comet outgassing has much decreased,
making the SW modifications less useful. This may
change near the end-of-mission when very low altitude
orbits will be flown by the orbiter before its planned
final touchdown.
July 13-17, Laurel MD USA.
http://ippw2016.jhuapl.edu/
14
IPPW-13 Program Abstracts - Missions Session
EARTH ENTRY VEHICLE DESIGN FOR COMET SURFACE SAMPLE RETURN. T. R. White1, R. W. Maddock2, C. D.
Kazemba3, R. G. Winski4, J. A. Samareh2, D. S. Adams5,
1
NASA Ames Research Center, Moffett Field, CA, 94035, [email protected]
NASA Langley Research Center, Hampton, VA, 23681, [email protected]
3STC Corporation, NASA Ames Research Center, Moffett Field, CA, 94035, [email protected]
4
Analytical Mechanics Associates, Inc., Hampton, VA, 23681, [email protected]
5
Johns Hopkins University Applied Physics Laboratory, Laurel, MD, 20723, [email protected]
2
Introduction: The 2013 Decadal Survey for New
Frontiers missions identifies several high-value science
missions, including Comet Surface Sample Return
(CSSR) [1]. The goal of a CSSR mission is to advance
the scientific community’s fundamental understanding
of the origin of the solar system and the contribution of
comets to the volatile inventory of the Earth. The
CSSR mission has several fundamental scientific requirements to meet this goal. CSSR would acquire and
return to Earth for laboratory analysis a macroscopic (≥
500 cc) sample from the surface of a comet nucleus.
The sample would be collected with a technique that
preserves complex organics and stored to prevent any
aqueous alteration of the sample.
Once the sample is in a laboratory on Earth, the
sample would be analyzed to determine the nature of
cometary matter. An entry capsule, or earth entry vehicle (EEV), would be required to protect the scientific
payload from the extreme conditions of atmospheric
entry, descent, and landing.
The Decadal Survey Mission Concept Study [2],
along with an APL 2007-2008 Comet Surface Sample
Mission Study [3] details several of the driving requirements for a CSSR EEV; these include a payload
volume and mass and inertial entry velocity of ~ 9
km/s. The mission concept study selected a MultiMission Earth Entry Vehicle (MMEEV) design concept derived from the Mars Sample Return (MSR) entry capsule design because of its increased reliability
over a parachute-based vehicle [4], [5]. This presentation will explore the entry vehicle design space associated with a CSSR mission, including trajectory options,
aerothermal environments, terminal descent conditions,
and thermal protection system materials.
References:
[1] National Research Council, “Visions and Voyages for Planetary Science in the Decade 2013-2022,”
The National Academies Press (2011). [2] Veverka, J.,
Johnson, L., Reynolds, E., “Mission Concept Study:
Comet Surface Sample Return (CSSR) Mission,” Prepared for the Planetary Science Decadal Survey
(2011). [3] The Johns Hopkins University Applied
Physics Laboratory, “Comet Surface Sample Return
Mission Study,” Prepared for NASA’s Planetary Science Division (2008). [4] Maddock, R. W., “Multi-
July 13-17, Laurel MD USA.
Mission Earth Entry Vehicle Design Trade Space and
Concept Development Status,” 7th International Planetary Probe Workshop (2010). [5] Maddock, R., Henning, A., Samareh, J., “Passive vs. Parachute System
Architecture for Robotic Sample Return Vehicles,”
IEEE Aerospace Conference (2016).
http://ippw2016.jhuapl.edu/
15
IPPW-13 Program Abstracts - Missions Session
Saturn PRobe Interior and aTmosphere Explorer (SPRITE). A. A. Simon1, D. Banfield2, D. Atkinson3, S.
Atreya4, W. Brinckerhoff1, A. Colaprete5, A. Coustenis6, L. Fletcher7, T. Guillot8, M. Hofstadter9, J. Lunine2, P.
Mahaffy1, M. Marley5, O. Mousis10, T. Spilker11, M. Trainer1, C. Webster9. 1NASA Goddard Space Flight Center,
2
Cornell University, 3Univ. Idaho, 4Univ. Michigan, 5NASA Ames Research Center, 6LESIA, Observ. ParisMeudon, CNRS, Paris Univ. 6 and 7, France, 7Univ. Leicester, 8Observatoire de la Cote d'Azur CNRS / Laboratoire
Cassiopée, 9Jet Propulsion Laboratory, 10Laboratoire d'Astrophysique de Marseille, 11Independent Consultant
Introduction: The Vision and Voyages Planetary
Decadal Survey identified a Saturn Probe mission as
one of the high priority New Frontiers mission targets
[1]. Many aspects of the Saturn system will not have
been fully investigated at the end of the Cassini mission, because of limitations in its implementation and
science instrumentation. Fundamental measurements
of the interior structure and noble gas abundances of
Saturn are needed to better constrain models of Solar
System formation, as well as to provide an improved
context for exoplanet systems. The SPRITE mission
will fulfill the scientific goals of the Decadal Survey
Saturn probe mission. It will also provide ground truth
for quantities constrained by Cassini and conduct new
investigations that improve our understanding of Saturn’s interior structure and composition, and by proxy,
those of extrasolar giant planets.
Key Science Questions: At the end of its 13-year
mission, Cassini will have extensively studied Saturn’s
upper atmosphere (troposphere to ionosphere) through
a mix of imaging, spectroscopy, occultations, and other
means. It will also have provided some gravity constraints on its core size. However, the answers to several questions remain elusive, simply because Cassini
was not designed to address them. Among these are:
1. What are the noble gas abundances? The
abundance of helium, in particular, is needed
to understand where (and when) Saturn
formed, and how it has continued to evolve.
[2,3,4]
2. What is the deep water abundance? Water is
key to convective processes, and is governed
by where Saturn formed and planetesimal delivery. [4,5]
3. What is Saturn’s deep interior structure? The
presence of a core, and any layered structure,
is also determined during formation and tests
instability models in the protosolar nebula.
[4, 6]
SPRITE: The SPRITE mission will address these
measurements primarily through delivery of an atmospheric entry probe. A probe allows direct measurement of composition and atmospheric structure along
its descent path. This provides information on regions
that were not accessible to Cassini remote sensing
measurements, and provides ground truth of retrieved
tropospheric parameters. In addition to temperature,
July 13-17, Laurel MD USA.
pressure and wind velocities, some quantities are even
more difficult to constrain from remote sensing. For
example, although analytical methods have attempted
to determine helium abundance, they are dependent on
model assumptions and can only place limits on the
actual value to within the fidelity of those assumptions.
A probe will provide an absolute direct measurement
that can be used to validate the accuracy of these
methods. This will determine if helium abundance can
be reliably retrieved from remote sensing data for other
planets, to better inform formation models.
References:
[1] Vision and Voyages for Planetary Science in
the Decade 2013-2022, Space Studies Board, ISBN:
978-0-309-22464-2
[2] Ben-Jaffel, L. and I. Abbes 2015. J. Phys.:
Conf. Ser. 577, 012003
[3] Encrenaz, T. 1990 Rep. Prog. Phys. 53, 793
[4] Guillot, T. 2005 Annual Review of Earth and
Planetary Sciences 33, 493
[5] Wang, D. et al. 2015 Icarus 250, 154
[6] Helled, R. et al. 2014. Giant Planet Formation,
Evolution, and Internal Structure in Protostars and
Planets VI, U. Arizona Press.
http://ippw2016.jhuapl.edu/
Credit: T. Balint
16
IPPW-13 Program Abstracts - Missions Session
THE BEE: A BIOSIGNATURE EXPLORER TO SAMPLE PLUMES OF OCEAN WORLDS. P. R. Mahaffy1, R. Arevalo1, S. K. Atreya2, M. Benna3, W. B. Brinckerhoff1, R. Danell4, J. P. Dworkin1, J. Eigenbrode1, C.
Freissinet5, J. Garvin1, S. Getty1, D. P. Glavin1, T. Hoehler6, T. Hurford1, R. Lorenz7, J. Nuth1, M. Ravine8, P. Spi1
NASA Goddard Space Flight Center, Code 690, Greenbelt, MD 20771
daliere1 and R. Summons9.
2
([email protected]), AOOS Dept., University of Michigan, Ann Arbor, MI 48189, 3CRESST, University
of Maryland Baltimore County, Baltimore, MD 21228, 4Danell Consulting, Winterville, NC 28590, 5CRESST,
University of Maryland Baltimore County, Baltimore, MD 21228, 6NASA AMES Research Center, Moffett Field,
CA 94035, 7Johns Hopkins University, Laurel, Maryland 20723, 8Malin Space Science Systems, San Diego, CA
92191, 9MIT, Cambridge, MA 02139.
Introduction: The possibility of the presence of
life in ocean worlds in our solar system is a compelling
driver for a detailed exploration of icy satellites of the
giant planets such as Europa, Titan, and Enceladus in
the decades ahead. A variety of energy sources may
exist to support microbial life in these environments
(Figure 1), leaving both free organic molecules and
cellular material in the ocean waters. We here describe
the Biosphere Explorer for Europa (BEE) that was
designed at Goddard Space Flight Center (GSFC) in
response to a directive from NASA to explore options
for possible augmentations to the Europa Multi Flyby
Mission (EMFM) mission to directly search for life at
Europa. The EMFM investigations were selected to
study the habitability of that moon but not to directly
search for extant life. In response to this challenge to
extend these investigations the BEE was designed as a
probe to be released from the EMFM, to actively target
and fly through a plume at a nominal altitude of 5 km,
collect material, and then search for molecular signatures of life in these gas and icy particles vented into
space from Europa’s interior ocean. Regardless of the
archecticture ultimately selected for exploration of
Europa with the EMFM mission, the BEE study provides a case study example of how a robust search for
signs of life may be realized on targets such as Encela-
Figure 1. Cartoon of possible sources of energy and nutrients at ocean/mantle and ice/water boundaries, radiation processes and
mixing with exogeneous material at the surface. The BEE approach to fly through an active plume and secure a taste of samples
that moments before might have been in a liquid environment provides a direct search for biosignatures and avoids the cost and
risk of landing on the surface.
July 13-17, Laurel MD USA.
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17
IPPW-13 Program Abstracts - Missions Session
dus or Europa without incurring the risk and cost of
landing on the icy surface of an ocean world.
Characteristics of Molecular Biosignatures: A
range of molecular biosignatures give evidence of extinct or extant life in terrestrial environments. These
include [e.g. 1] patterns in the distribution of molecular
weights of organic compounds that are structurally
related, patterns of repeating units, structural preference for chain rather than branched compounds, enantiomeric excesses, and distinct isotopic signatures of
biological activity. In fact, analog studies have shown
that it is even possible to distinguish between a living
biota, a recently extinct biota, a long extinct biota or an
abiotic environment by looking at the distribution of
the organic molecules present in the sample [e.g., 2,3].
For example, the presence of phosphoric acid and nucleobases in Lake Hoare samples from Antarctica suggest a living biota from the presence of DNA. The terrestrial building blocks of nucleobases, proteins, and
ultimately RNA and DNA are amino acids and the
building blocks of cell walls are fatty acids and their
derivatives. The presence of a wide range of amino and
carboxylic acids reveals a recently extinct to extant
biota, while the presence of the more robust carboxylic
acids (fatty acids) with repetitive masses or with higher
abundance of molecules with an even number of carbon suggests remnants of a long-time extinct biota.
Synergy of Separation and Mass Spectrometer
Techniques: Liquid or gas separation techniques combined with mass spectrometric analysis are the tool of
choice for definitive identification of organic molecules in terrestrial environments. Either technique
alone leaves ambiguity in the chemical analysis necessary for definitive identification of molecular biosignatures. For space applications, a gas chromatograph mass spectrometer (GCMS) is the most robust
tool. The GCMS technique has been successfully implemented on the Sample Analysis at Mars (SAM)
instrument in the Curiosity Rover with the first in situ
detection of organic molecules on this planet [4]. A
GCMS based on an advanced ion trap mass spectrometer is presently being developed for the ExoMars mission [5]. Its sensitivity in the GCMS mode is comparable to that of high end laboratory instrumentation and
exceeds that of other mass spectrometers developed for
space applications.
Thermochemolysis, Enatiomeric Separation of
Chiral Compounds, and Tandem Mass Spectrometry for Definitive Identification of the Molecules of
Life: Chemical transformation of a polar molecule into
a more volatile product molecule by introduction of a
suitable reagent, is necessary to analyze the widest
possible range of the molecules of life (amino acids,
amines, sugars, and carboxylic acids) by GCMS tech-
July 13-17, Laurel MD USA.
niques. With efficient transformation of these molecules into species that are readily detected by a GCMS,
patterns in molecular weight and chemical type will
reveal distinct and definitive signatures of life. The
ability of tandem mass spectrometry in the ion trap to
selectively isolate a high molecular weight compound from the other species present in the ion trap,
excite the compound and cause it to dissociate, and
analyze its fragmentation pattern provides even more
information on chemical structure.Advanced GC columns allow enantiomeric separation of chiral compounds of astrobiological interest such as amino acids
– yet another tool to search for biosignatures.
Analog Studies Demonstrate Approach: With the
inclusion of ocean worlds as an emerging target for
NASA, the mass spectrometer team at GSFC in collaboration with astrobiology colleagues has initiated a
study of biosignature detection in various terrestrial
analog environments, such as coastal upwelling and
ocean gyre center, alkaline springs, and deep-sea hydrothermal vents using the techniques described. These
studies enable a comparison of analytical techniques
and protocols and the promising results of these studies
will be presented.
Mission Design, Plume Targeting, Multiwavelength Imaging, and Planetary Protection: The
details of the mission design to enable plume targeting
in the context of the EMFM will be described by other
presenters at this conference. Advanced imaging systems in the IR, visible, and UV enable characterization
of plume and source region morphology. The measurement techniques described could form the core of a
ground-breaking mission to interogate the Enceladus
plumes for signs of life and move toward an answer of
the fundamental question of the existence of life in
other parts of our solar system.
References: [1] Summons, R. E. et al. (2008)
Space Sci. Rev. 135, 135-159. [2] Bishop, J. L. et al.
(2013) Icarus 224, 309-325. [3] Siljestrom, S. C. et al.
(2014), Astrobiology, 14, 780-797. [4] Freissinet, C.
(2015) JGR, 120, 495-514. [5] Brinckerhoff, W. B.
Proc.
Aerospace
Conf
IEEE,
DOI:
10.1109/AERO.2013.6496942.
http://ippw2016.jhuapl.edu/
18
IPPW-13 Program Abstracts - Missions Session
A DESCENT PROBE FOR EUROPA AND THE OTHER GALILEAN MOONS OF JUPITER. P. Wurz1, D.
Lasi1, N. Thomas1, D. Piazza1, A. Galli1, M. Jutzi1, S. Barabash2, M. Wieser2, W. Hadjas3, and H. Lammer4,
Physikalisches Institut, University of Bern, 3012 Bern, Switzerland ([email protected]), 2Swedish Institute
of Space Physics, Kiruna, Sweden, 3Paul Scherrer Institut, Villingen, Switzerland, 3Space Research Institute, Austrian Academy of Sciences, Graz, Austria.
Introduction: We present a study of an impacting
descent probe for Europa (EDP) to increase the science
return of spacecraft orbiting or flying-by atmosphereless planetary bodies of the solar system, such as the
Galilean moons of Jupiter. EDP is a carry-on small
spacecraft (< 100 kg), to be deployed by the mother
spacecraft. After release, the descent probe brings itself
onto a collisional trajectory with the targeted planetary
body in a simple manner.
Science goals and payload: The foreseen science
payload includes instruments for surface imaging
(wide-angle camera, WAC), characterization of the
neutral exosphere (exosphere mass spectrometer,
EMS), magnetic field measurements (magnetometer,
MAG), plasma measurements (3D plasma analyzer,
3DPA), and a radiation monitor, near the target body
down to very low-altitudes, during the probe short
(∼minutes) and fast descent to the surface until impact.
The science goals and the concept of operation are
discussed with particular reference to Europa, including options for after-impact retrieval of very-low altitude science data.
Magnetosphere Interactions: in situ measurements
of the magnetic fields and currents. Determination of
ionospheric plasma populations currents, to identify all
external magnetic field soruces from Europa’s induced
magnetic field, and search for an intrinsic dipolar field.
Exosphere: EMS mass spectra along the descent
trajectory to derive abundance of major species to address question on the formation, down to trace species
for astrobiology and noble gases.
Geochemistry and Geology: Interpretation of the
EMS mass spectra and the WAC images to derive
mineralogy and geological domains on the surface, in
particular areas with low ice abundance.
Astrobiology: Search for biosignatures in the EMS
mass spectra, like hydrocarbons or sulfur-bearing molecules.
Engineering Objectives: In addition, there are also engineering objectives the EDP will address:
Surface topography: From the WAC images the
structure of the surface at length scales of 30 cm will
be recorded to support future landings on Europa’s
surface.
Radiation environment: The fluxes of penetrating
radiation near the surface will be recorded to understand the radiation environment for future landers.
July 13-17, Laurel MD USA.
Mission Scenario: A sketch of the foreseen mission scenario is given below. The EDP will be released
about 24 h before closest approach (CA) from the main
spacecraft. The probe will decelerate to enter a collision trajectory with the object. Because EDP moves at
a slower speed its prime science time is when the main
spacecraft already passed CA, and the main spacecraft
can be used to relay the data from the EDP to Earth.
Summary: All in all, we demonstrate how EDP
has the potential to provide a high science return to a
mission at a low extra level of complexity, engineering
effort, and risk. Given the moderate mass of EDP even
two such probes could be carried by the mother spacecraft and be used to investigate different surface locations.
This study builds upon earlier studies for a Callisto
Descent Probe (CDP) for the former Europa-Jupiter
System Mission (EJSM) of ESA and NASA [1,2], and
extends them with a detailed assessment of a descent
probe designed to be an additional science payload for
the NASA Europa Multiple Flyby Mission.
References:
[1] Wurz, P., N. Thomas, D. Piazza, M. Jutzi, W.
Benz, S. Barabash, M. Wieser, W. Baumjohann, W.
Magnes, H. Lammer, K.H. Glaßmeier, U. Auster, and
L. Gurvits, The Callisto Descent Probe, European
Planetary Science Congress, (2009) Vol. 4,
EPSC2009-375-2, 2009
[2] Wurz, P., S. Barabash, N. Thomas, J. Fischer,
D. Piazza, M. Jutzi, W. Benz, M. Wieser, W. Baumjohann, W. Magnes, H. Lammer, K.H. Glaßmeier, U.
Auster, S. Pogrebenko, L. Gurvits, and G. Managadze,
The Callisto Descent Probe, 9th International Planetary Probe Workshop (IPPW-9), Toulouse, France,
16th–22nd June 2012
http://ippw2016.jhuapl.edu/
19
IPPW-13 Program Abstracts - Missions Session
ESA’s CLEO/P study : 3 potential contributions to NASA’s Multi-flyby Europa mission. T. Voirin1, J. Larranaga2, J. Romstedt1, C.P. Escoubet1, R. Biesbroek1, D. Rebuffat1 S. Vijendran1
1
ESA-ESTEC ([email protected]), 2AURORA B.V. for ESA/ESTEC ([email protected]).
Following an ESA-NASA bilateral agreement in
2014, a mutual interest has been expressed by both
Agencies for studying a potential contribution of Europe, as a junior partner, to NASA's Europa Multiple
Flybys mission, formerly known as Clipper. Such a
contribution would be part of ESA’s Science Program
(Cosmic Vision) and would consist of a piggyback
spacecraft carried by Clipper during interplanetary
cruise and released by Clipper in the Jupiter system. It
would provide top-level science complementary to
ESA’s JUICE and NASA’s Clipper science objectives.
The CLEO/I or /E spacecraft configuration deployed
(left) and attached to Clipper (right)
A key requirement from NASA & JPL was that the
ESA spacecraft should not exceed 250 kg. Following a
preliminary brainstorming by ESA, including iterations
between system and science support teams, three possible piggyback concepts for such a contribution within
the mass constraint were identified for further study, in
agreement with NASA and JPL teams, namely (i) a
spacecraft performing several flybys of Io (e.g. Io active volcanism investigation) ; (ii) a spacecraft performing several flybys of Europa (e.g. for Europa
plumes in-situ assessment) and (iii) a Europa penetrator concept, with high velocity impact on Europa and
subsurface investigations (including a habitability
package).
Left : the CLEO/P penetrator penetrating the ice ;
Right : the CLEO/P spacecraft, including Penetrator
Delivery System and the penetrator (courtesy of Airbus Defence & Space UK)
Spacecraft concepts such as a Europa orbiter and a
Europa lander, although scientifically meaningful,
were not considered feasible within the allocated mass
envelope of 250 kg and as a consequence were not
studied further.
These three pigyyback concepts were subject to a dedicated ESA-internal “Phase 0” system study, carried
out in ESA’s Concurrent Design Facility (CDF) in
2015. This study was called CLEO/P: Clipper ESA
Orbiter or Penetrator. The CDF study concluded that
CLEO/P concepts would be technically feasible, and
with respect to the related schedule would also meet
programmatic contraints.
This paper will present an overview of the CLEO/P
study outcomes in terms of mission concepts and ESA
piggyback spacecraft designs.
July 13-17, Laurel MD USA.
http://ippw2016.jhuapl.edu/
20
IPPW-13 Program Abstracts - Missions Session
GLOBAL AERIAL EXPLORATION OF OUR SISTER WORLD WITH THE VENUS ATMOSPHERIC
MANEUVERABLE PLATFORM (VAMP): MISSION SCIENCE OBJECTIVES AND POTENTIAL
INSTRUMENTATION. K. H. Baines1, S. S. Limaye 1, G. Lee2, and B. Sen2, 1Space Science and Engineering
Center, University of Wisconsin-Madison, Madison, WI, USA ([email protected]), 2 Northrop Grumman
Aerospace Systems, Redondo Beach, CA, USA.
Introduction: VAMP, the Venus Atmospheric
Maneuverable Platform, under development by
Northrop Grumman, is a versatile twin-engine buoyant
aircraft capable of sustained (> months) exploration of
Venus. Utilizing both dynamic and buoyant lift, the
flying-wing-shaped aerial rover is capable of exploring
a wide range of altitudes from its 50-km free-floating
“safe-haven” level to over 65 km in altitude. Its solarpowered twin electric engines not only provide power
for vertical ascents, but also the power for unprecedented mobility, enabling the aircraft to cruise up to ~
30 knots airspeed, and thus allowing poleward/equatorward aerial excursions extending over
1400 km (over 12 degrees of latitude) per terrestrial
day. Over 4-5 days, the planet’s ~180 knot zonal
wind enables the craft to circle the planet exploring all
longitudes and times-of-day.
Fig.1 : The VAMP hybrid aerial rover exploring the
skies of Venus, powered by twin solar-powered
motors
As currently envisioned, VAMP provides unprecedented large amounts of payload mass, power, and
volume for an in-situ Venus explorer. While still under
assessment, it is clear that VAMP will provide more
than 20 kg for science instrumentation with electrical
power exceeding several kilowatts during daylight
hours and perhaps a kilowatt during nighttime conditions. The relatively large size of the aircraft – with its
wings spanning more than 15 meters – provides opportunities for instrumentation requiring relatively large
volumes and/or space for an array of apertures (e.g.,
various forms of radar or electromagnetic detectors).
Atmospheric Science with VAMP: Objectives
and Techniques: VAMP thus provides an unusually
versatile platform for the in-situ aerial exploration of
Venus, conducting an array of novel measurements
that promise to provide crucial insights into virtually
all aspects of Venus atmospheric science, including (1)
the planet’s origin and evolution, (2) its active and
July 13-17, Laurel MD USA.
varying chemistry, driven by latitudinally, time-of-day,
and vertically varying photochemical/thermodynamical
processes, and (3) its global circulation, dynamics, and
meteorology. Via mass spectrometry (MS), new insights into the origin and evolution of Venus can be
provided through accurate measurements of the D/H
ratio and the noble gases and their isotopes over both
altitude and time-of-day, to correct for fractionation
effects. Via tunable laser spectrometry (TLS), the isotopes of other light elements (e.g., nitrogen, carbon,
and oxygen) can be measured as well, providing additional insights into Venus’ origin and evolution.
VAMP provides in-situ sampling of key reactive
gas species such as H2O, CO, OCS, and SO2 , and can
do so regularly over altitude, latitude, and time-of-day
via the MS, TLS and/or a near-infrared spectrometer
operating in the 1-2.7-µm range. Using a nephelometer that includes a high-resolution optical microscope
for aerosol imaging, the size, shape, and chemical
composition of aerosols can be accurately determined,
which, together with the reactive gas abundance data,
promises to provide additional valuable insights into
chemical cycles within Venus’ dynamic clouds.
VAMP’s mobility promises to be extremely effective at measuring crucial aspects of the planet’s dynamics and circulation, including local meteorological
effects. The aerial rover’s ability to travel across nearly
the entire globe over several weeks (likely limited by
diminishing solar power poleward of ~ 70o latitude)
enables it to measure key aspects of any Hadley cells
as well as the characteristics of planetary and gravity
waves over nearly the entire planet. Using Doppler
radar, it can measure its ground speed both day and
night and thus accurately measure both the meridional
and zonal winds from 50 to ~ 65 km altitude. Its pressure (P) and temperature (T) sensors will continually
sample the atmosphere. Vertical traverses (typically
both ascents during the day, and descents from high
altitudes during the night), will allow the temperature
gradient (dT/dz) to be assessed, from which the stability of the atmosphere, as a function of altitude, can be
determined. A key parameter for understanding the
planet’s thermal structure and stability at lower altitudes is the vertical variability of the N2 abundance.
While commonly considered to be constant at 3.5%,
previous probes strongly suggest some 40% variability
from ~ 22 km to ~52 km altitude. VAMP is well-suited
to repeatedly measure N2 and its vertical variability
above 50 km as observed over day/night conditions
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21
IPPW-13 Program Abstracts - Missions Session
and latitude. Any confirmed variability would have
strong implications on the planet’s lapse rate, thermal
structure, stability, and flux of material, temperature,
and momentum from near the surface to the cloud level, potentially providing significant new insights into
mechanisms driving the planet’s circulation, including
its not-well-understood super-rotation. Within the
clouds, the vertical component of the wind can be
measured from an on-board vertical wind sensor combined with the pressure (P) data, from which, when
combined with the dT/dz information, the relative roles
of convection and vertical waves (e.g., gravity waves)
can be assessed over various terrains as well as latitudes and time-of-day. Investigations of vertical dynamics combined with measurements of lightning from
an onboard lightning detector will provide new insights
into the role lightning and convective storms play in
Venus’s meteorology and chemistry, particularly in the
production of lightning-generated species (e.g., NO).
Additional information over altitude comes from two
other aspects of a likely mission. First, during atmospheric entry, VAMP’s low-density design enables it to
slow to “observing speed” above ~ 90 km altitude,
enabling the aircraft to make in-situ measurements
from well above the unexplored UV aerosol layer
down to ~ 50 km level. Second, the relatively large
payload capability allows the possibility for both dropsondes and balloon-borne “rise sondes” to be deployed, sampling both lower and higher altitudes than
the 50-~65 km altitude regularly sampled by VAMP.
Surface/Geologic Science with VAMP: Objectives and Techniques: Beyond aerial exploration for
atmospheric science, VAMP also provides a valuable
platform for discovering new insights into the planet’s
surface geology and interior. RADAR maps and
nighttime near-IR images can be used to characterize
the surface topography, surface texture, and crude
chemical make-up (e.g., igneous vs basaltic rocks),
from which geological insights (e.g., the extent and
relative age of surface volcanism) can be made. As
well, an array of aural seismic detectors can be deployed which listen for the deep rumble of seismic
events. As well, a large (multi-meter-wide) electromagnetic array carried aboard VAMP could possibly
sound more than 10 km below the planet’s surface, to
map the depth of the lithosphere.
Conclusion: VAMP thus provides a particularly
versatile aerial platform for the exploration of nearly
the entire planet, with particular emphasis on sampling
highly diagnostic gases, aerosols, winds, temperatures,
pressures and lightning characteristics, as well as for
mapping key characteristics of surface geology. As
such, it is an ideal platform around which to base an
internationally collaborative mission.
.
July 13-17, Laurel MD USA.
http://ippw2016.jhuapl.edu/
22
IPPW-13 Program Abstracts - Missions Session
DAVINCI: DEEP ATMOSPHERE VENUS INVESTIGATION OF NOBLE GASES, CHEMISTRY, AND
IMAGING. L. S. Glaze1, J. B. Garvin1, N. M. Johnson1, M. J. Amato1, J. Thompson1, C. Goodloe1, D. Everett1, and
the DAVINCI Science Team, 1NASA Goddard Space Flight Center (Code 690, Greenbelt, MD, 20771,
[email protected]).
Introduction: DAVINCI is one of five Discoveryclass missions selected by NASA for Phase A studies.
Launching in November 2021 and arriving at Venus in
June of 2023, DAVINCI would be the first U.S. entry
probe to target Venus’ atmosphere in 45 years.
DAVINCI is designed to study the chemical and isotopic composition of Venus’ atmosphere at a level of
detail that has not been possible on earlier missions
and to image the surface at optical wavelengths and
process-relevant scales.
Science: Venus and Earth experienced vastly different evolutionary pathways resulting in unexplained
differences in atmospheric composition and dynamics,
as well as in geophysical processes of the planetary
surfaces and interiors. Understanding when and why
the evolutionary pathways of Venus and Earth diverged is key to understanding how terrestrial planets
form and how their atmospheres and surfaces evolve.
DAVINCI would provide these missing puzzle pieces
needed to understand terrestrial planet formation and
July 13-17, Laurel MD USA.
evolution in the solar system and beyond. The mission
is tightly focused on answering fundamental questions
that have been ranked as high priority by the last two
National Research Council (NRC) Planetary Decadal
Surveys [1-3] as well as by the Venus Exploration
Analysis Group (VEXAG) since the time of its inception in 2005 [4]. For example, DAVINCI will make
measurements of the heaviest noble gases, including
the first ever measurements of xenon [5]. These definitive measurements, which would be made well below
the homopause to avoid any ambiguity, are sufficient
to answer questions as framed by the NRC Planetary
Decadal Survey and VEXAG, without the need to repeat them in New Frontiers or other future missions.
The three major DAVINCI science objectives are:
• Atmospheric origin and evolution: Understand the
origin of the Venus atmosphere, how it has
evolved, and how and why it is different from the
atmospheres of Earth and Mars.
• Atmospheric composition and surface interaction:
Understand the history of water on Venus and the
chemical processes at work in the lower atmosphere.
• Surface properties: Provide insights into tectonic,
volcanic, and weathering history of a typical tessera terrain.
Mission Design: The DAVINCI probe will make
in situ measurements during its one-hour descent
through the Venus atmosphere. The descent sphere
itself builds on the successful Pioneer Venus Large
Probe design. The descent sphere and payload are protected during intial atmopsheric entry by a solid body
aeroshell.
The DAVINCI probe would be delivered to Venus
by a carrier/telecommunications spacecraft (built by
Lockheed Martin). The spacecraft first encounters
Venus four months after launch. This initial flyby enables targeting, when the spacecraft returns to Venus 15
months later, of the probe atmospheric entry location
for optimized lighting conditions in the tessera region
chosen for descent imaging. The probe is released a
few days before the second Venus encounter and the
spacecraft communicates directly with the probe
throughout coast, entry and descent. The probe employs a two-parachute system to extract the descent
sphere from the entry system and to slow descent.
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23
IPPW-13 Program Abstracts - Missions Session
The entire science payload is contained within the
pressure and temperature controlled descent sphere.
All science data are collected and relayed to the flyby
spacecraft during descent. DAVINCI has no requirement to survive touchdown, however, the descent
sphere carries sufficient resources (e.g., power, thermal
control) to continue science operations and data relay
for ~20 minutes on the surface. After loss of contact
with the probe, the spacecraft begins relay of all data
back to Earth.
Payload: DAVINCI builds on the tremendous
success of the Mars Science Laboratory Sample Analysis at Mars (MSL/SAM) suite carried on the Curiosity
rover [6-13], by pairing the Venus Mass Spectrometer
(VMS) led by NASA’s Goddard Space Flight Center
with the Venus Tunable Laser Spectrometer (VTLS)
led by the Jet Propulsion Laboratory. Combined, these
two instruments provide the first comprehensive measurements of noble and trace gas species, as well as key
elemental isotopes.
These two state-of-the art instruments are complemented by the Venus Atmospheric Structure Investigation (VASI), which provides measurements of the
structure and dynamics of the Venus atmosphere during entry and descent as context for the chemistry
measurements, and enables reconstruction of the descent profile.
The Venus Descent Imager (VenDI) provides highcontrast descent imaging of the tessera terrain. Malin
Space Science Systems is leveraging experience with
the Curiosity Rover’s Mastcam and MARDI descent
video imaging systems to develop VenDI.
Conclusions: An atmospheric probe, leveraging
proven 21st Century instrument technology, definitively resolves key Venus atmospheric science questions.
Imaging of tessera at scales relevant to a lander will
resolve radar ambiguities and uncertainties. DAVINCI
will meet multiple, high-priority National Academy of
Sciences goals, while also serving as a pathfinder for
future orbital radar missions and landed missions to the
Venus highlands.
References:
[1] Crisp, D., et al. (2002) ASP conference Series,
272, Ed. MV Sykes, 5-34. [2] New Frontiers in the
Solar System (2003) National Research Council of the
National Academies, National Academies Press.
[3] Visions and Voyages (2011) National Research
Council of the National Academies, National Academies
Press.
[4] VEXAG
(2014)
http://www.lpi.usra.edu/vexag/reports/GOI140625.pdf. [5] Trainer et al. (2016) InternationalVenus Conference, Oxford. [6] Mahaffy et al. (2015)
Science, 347, 412-414. [7] Webster et al. (2015) Science, 347, 415-417. [8] Atreya et al. (2013) GRL, 40,
July 13-17, Laurel MD USA.
5605-5609. [9] Mahaffy et al. (2013) Science, 341,
263-266. [10] Webster et al. (2013) Science, 341, 260263. [11] Wong et al. (2013) GRL, 40, 6033-6037. [12]
Conrad et al. (2014) LPSC XLV, Abstract #2366. [13]
Webster et al. (2016) International Venus Conference,
Oxford.
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24
IPPW-13 Program Abstracts - Missions Session
Biosignature Explorer for Europa (BEE) Probe –Directly Searching for Life Evidence on Europa. Michael J.
Amato1, P. Spidaliere1, P. Mahaffy1, C. Schiff1, O. Hsu1, T. Hurford1, M. Benha1, W. Brinckerhoff1, J. Garvin1, J.
Downing1, T. Errigo1, D. Glavin1, M. Sarantos2, R. Lorenz3, T. Hoehler4, et al. 1NASA Goddard Space Flight Center
(GSFC), Greenbelt MD. 2 University of Maryland Baltimore County/NASA Goddard Space Flight Center, 3 JHU
Applied Physics Laboratory, 4 NASA Ames Research Center,
Introduction:
Evidence for Europa’s substantial sub crustal water
ocean leaves us with the curcial question of if the
ocean is habitable and if it harbors life.
The tantalizing possibility of hydrothermal activity
below its ice crust shell has placed Europa as one of
the highest priority targets in the search for habitable
environmentsand potentially extant life [NRC, 2011].
The compositional analysis of potential plumes is a
high-value objective. Sporadic eruptive plumes at Europa have been observed [Roth et al., 2013], and analysis shows plume activity is likely at lower intensities
The plumes represent an opportunity to uniquelyprobe the chemistry of the subsurface ocean and assess
Europa’s potential to sustain life by looking for bio
signatures. Freshly-ejected ocean material would represent a relatively unaltered sample of the subsurface
chemistry, as compared to sputtered surface materials
exposed to high energy radiation that will destroy organic compounds. In addition to the detection of more
pristine organic molecules, the composition of the other constututnes such as salts in the ocean has important
implications for the source of ocean materials [e.g.,
Brown and Hand, 2013].
The potential changing intensity of the plumes at
Europa calls for a versatile measurements strategy that
can accommodate a wide range of geographical locations and outgassing intensities. While the NASA Europa mission spacecraft is well equipped for Europa
studies, which include plume detection and characterization, more is needed to fully analyze Europa plumes.
The recently selected instrument suite likely lacks the
ability to achieve the highly desirable and difficult detection of direct biosignatures or life evidence. In addition, the Clipper mission may not be able to easily
modify its orbital trajectory or altitude to fly through
plumes or remotely study plume events that may be
short lived or highly diffuse. Thus, a smaller Probe
equipped with the focused set of instruments and navigation capabilities is better suited to target detection of
bio signatures and can target denser plumes and lower
altitudes that might be otherwise inaccessible to the
Europa Clipper spacecraft.
The BEE plume probe:
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A small plume probe would have more flexibility to
perform the critical science investigations in support of
the goal of exploring Europa plumes for evidence of
past or current life on Europa. Objectives to meet this
goal could include: 1) Characterizing the building
blocks of life within the plumes, 2) investigating plume
source regions to assess them as a biological niche environment and 3) further assess plume source regions
for future landed missions.
Our team has designed a Biosignature Explorer for
Europa (BEE) Probe concept to ‘taste’ the ocean by in
situ analysis of plume sample for biosignatures, which
provide the most science and most programmatically
robust way to determine if the Europa ocean harbors
life evidence. By flying directly through a plume, the
BEE is able to sample freshly released ocean water and
search for evidence of extant life. BEE does this by
using newly matured collection approaches and mass
spectrometer designs based leveraging heritage approaches. The search for direct in situ molecular biosignatures is the clearest path toward to definitive
identification of signatures of life as we know it at Europa.
The BEE will search for molecular signatures of
life by capturing material soon after it is released from
a subsurface reservoir, and conduct chemical analysis
with experiments optimized for detection of molecular
biosignatures. Plume fly-through with sampling and
molecular analysis is akin to “landerless landing” in an
ocean (or fresh ocean deposit) in the quest for Europa
ocean biosignatures
The BEE fly-through approach may offer many
advantages over static landings. BEE plume sampling
collects intact biomarker material before their inevitable destruction by radiation after release from the
ocean. BEE offers better access to freash material by
targetating plumes or active targets (2-10 km fly
through corridor vs. lander Braking-Descent-Landing
(BDL) uncertainty of at least 75-100km or worse).
BEE is less sensitive to radiation damage and effects
on sensitive instrumentation. BEE has no landing loads
on sensitive bio-molecule sensors. BEE’s broad regional context can be established with simple imaging
systems.
BEE can be more agile and responsive to activity
on Europa when we arrive with the Europa mission,
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IPPW-13 Program Abstracts - Missions Session
allowing easier targeting to the “the action”. BEE has
no BDL lander systems and cost, uses less resources,
has less complexity, has fewer mission constraints and
no landing risks that will drive additional costs. BEE
has an advanced NASA Goddard Space Flight Center
led mass spectrometer with a large area collection approach that leverages past designs while enabling new
direct biosignature science. The sensitive mass spectrometer is combined with other separation approaches
for definitive identification of biosignatures. It also
carries the BEE UV plume targeting camera as well as
visible and IR cameras to image the active region with
better resolution than the Europa mother ships instruments.
The BEE team has refined its cadence of prerelease
survey, probe release, refined targeting, sample collection, analysis and transmit operations. BEE is released
from the mother ship many hours before closest approach to Europa. Initial targeting is done using plume
data from the Europa mission instrument suite. Refined
targeting on a plume is aided by BEEs unique targeting
camera that senses emissions night or day. The BEE
probe flies thru at very low km altitude and collects
material. The probe images the surface in visible and
infrared at process-diagnostic scales. After exiting the
intense radiation environment, it uses proven mass
spectrometer technology to analyze the material for
biosignatures. The BEE then transmits the data back to
the Europa mission mother spacecraft. The BEE can be
released during a large number of the baselined flybys.
The BEE uses its refined targeting and propulsion system to enable targeted access a majority of Europa’s
surface.
The small BEE probe attaches to the Clipper mission, currently on its NADIR viewing side. The BEE
team has worked with the Europa mission project engineering team to work out initial mechanical, load, electrical, communications and operations details that have
low cost and resources impact on the main mission.
BEE employs a modular mechanical design and a carefully designed internal radiation protection vault to
protect sensitive electronics from radiation effects and
is under 250 Kg.
The BEE probe ACS and propulsion system are designed to enable targeting and post sample collection
maneuvers. BEE is three axis stabilized and utilizes
acceleration measurement systems, star sensors and
other packages. The propulsions system is a hybrid
system combining a basic bi-propellant design with a
simple hydrogen driven three axis cold gas system that
is compatible for use just before and during sample
collection.
The BEE’s avionics utilize a selectively redundant
design that leverages multiple NASA Goddard Space
Flight Center (GSFC) systems designed for far from
July 13-17, Laurel MD USA.
earth applications. The design has high performance
processor and memory units combined with a number
of interfaces cards. These interfaces include power and
data interfaces, propulsion and actuator interfaces, refined targeting sensor interfaces and redundant X-band
transponder. The BEE’s power system is currently a
heritage primary battery designed with multiple battery
cell strings.
The BEEs thermal system utilizes blanketing and
four thermal zones as well as survival heaters. The battery system is isolated from the electronics vault to
minimize heating requirements but the propulsion tanks
are thermally linked to the vault. A separate thermal
interface will be linked to the mother spacecraft thermal system during cruise.
The BEE probe is a feasible way to achieve critical biosignature and life evidence goals with less risk
and lower cost than other options. The BEE team has
shown this approach to be feasible approach to be considered.
Figure 1 – The BEE probe design and its current location on the Europa mission spacecraft.
Acknowledgments: The author would like to
acknowledge NASA Headquarters Planetary Science
Division PSD for follow on study support and the
many team members at NASA GSFC and other institutions involved in the BEE probe work.
References - [1] NRC, 2011, [2] Roth et al., 2013 [3]
Brown and Hand, 2013
http://ippw2016.jhuapl.edu/
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