Systems engineering from CDF to CDR:
the experience of CHEOPS,
ESA first small science mission
Carlos Corral van Damme
European Space Agency, ESTEC
SECESA 2016
Madrid
7 October 2016
ESA UNCLASSIFIED – For Official Use
CHEOPS: ESA First Small Science Mission
CHEOPS (CHaracterizing ExOPlanet Satellite)
•
first small class mission within the ESA Science
Program (Cosmic Vision 2015-2025)
•
selected for study in Oct 2012 by the Science
Programme Committee (SPC) and adopted for
implementation in Feb 2014 as ESA mission in
partnership with Switzerland and other member states
•
follow-up mission dedicated to investigating exo-planet
transits by performing ultra-high precision
photometry on bright stars which are already known to
host planets
Carlos Corral van Damme | SECESA 2016, Madrid | 07/10/2016 | Slide 2
ESA UNCLASSIFIED – For Official Use
CHEOPS: main challenges
•
S-class mission boundary conditions:
•
Very demanding schedule: development time not exceeding 4 years
•
Small budget: cost to the ESA Science Programme limited to 50 M€
•
Challenging science requirements: high photometric precision combined
with large accessible sky fraction
•
Multi-party cooperation scheme
•
Consistency with development practices and quality standards applicable to
all ESA missions
Carlos Corral van Damme | SECESA 2016, Madrid | 07/10/2016 | Slide 3
ESA UNCLASSIFIED – For Official Use
CHEOPS: from CDF to CDR
•
Phase B2/C/D/E1 started only after 1.5 years from the initial proposal
•
System CDR held after ~3.5 years
Carlos Corral van Damme | SECESA 2016, Madrid | 07/10/2016 | Slide 4
ESA UNCLASSIFIED – For Official Use
CHEOPS: mission design summary
Launch segment
Space segment
Orbit
•
Dawn-dusk SSO
•
LTAN 6 a.m.
•
Altitude: [650-800] km
Spacecraft
•
290 kg, 170 W
•
∼1.5x1.5x1.2m
•
Platform based on AS250
Instrument
•
32 cm aperture
Ritchey-Chrétien
telescope
•
60 kg, 60 W
Ground segment
Torrejon
VILSPA
Only LEOP
Mission Operations Centre (MOC)
Science Operations Centre (SOC)
•
•
•
Shared launch with
Soyuz from Kourou
CHEOPS inside ASAP-S
Q2-2018
Carlos Corral van Damme | SECESA 2016, Madrid | 07/10/2016 | Slide 5
ESA UNCLASSIFIED – For Official Use
CHEOPS: development status
Flight P/F (June 2016)
Courtesy of ADS-ECE
Courtesy of UBE
Flight Instrument Structure (Feb 2016)
Carlos Corral van Damme | SECESA 2016, Madrid | 07/10/2016 | Slide 6
ESA UNCLASSIFIED – For Official Use
CHEOPS: project implementation &
systems engineering approach
•
Project organization:
•
•
•
•
small teams ⇒ close coordination, fast decision process
Technology readiness:
•
re-use of an existing “off-the-shelf” platform (minimum modifications only)
•
new payload design, but based on available technologies
Industrial implementation approach:
•
single Invitation to Tender for the platform covering both parallel competitive study
phase (A/B1) and implementation
•
spacecraft prime contractor was allowed to select the equipment suppliers through
direct negotiation based on platform heritage
Early mission concept definition:
•
Industrial procurement approach only feasible when the initial mission concept and
requirements are mature enough.
•
Concurrent engineering is essential for a fast definition of mission concept and
requirements.
Carlos Corral van Damme | SECESA 2016, Madrid | 07/10/2016 | Slide 7
ESA UNCLASSIFIED – For Official Use
Early mission concept definition: the
experience of CHEOPS (1/2)
•
CHEOPS CDF study performed in 12 sessions from
Oct to Dec 2012, dealing with all mission aspects
(platform, payload, launch, G/S, operations).
•
Most design trades were identified, assessed and
solved during the CDF.
Design evolution
Proposal
CDF
PRR - SSTL
PRR - ADS
Parallel competitive Phase A/B1 industrial studies
Carlos Corral van Damme | SECESA 2016, Madrid | 07/10/2016 | Slide 8
ESA UNCLASSIFIED – For Official Use
CDR - ADS
Early mission concept definition: the
experience of CHEOPS (2/2)
Schedule evolution
Budgets evolution
CDF
•
Maturity and system margins essential
to maintain compatibility with budget
allocations
Carlos Corral van Damme | SECESA 2016, Madrid | 07/10/2016 | Slide 9
ESA UNCLASSIFIED – For Official Use
SRR
PDR
CDR
•
Delays will happen
•
Importance of incremental approach
Early mission concept definition:
requirements & performance model (1/2)
•
Early mission assessment is often performed in a design-centred approach,
where requirements are derived from the performances of the adopted design:
Preliminary
mission
design
Input
•
Evolved
mission
design
Feasibility
check
Mission assessment
Output
Requirements
But institutional missions (e.g. science) benefit more from a requirementscentred approach:
Mission
performance
model
Design space
exploration
Carlos Corral van Damme | SECESA 2016, Madrid | 07/10/2016 | Slide 10
ESA UNCLASSIFIED – For Official Use
Mission
Requirements
Early mission concept definition:
requirements & performance model (2/2)
An end-to-end mission performance model (even if simple) should be
available before early concurrent engineering activities.
•
Requirements are the most important output of the early mission assessment.
•
Requirements are contractual ⇒ rigidity
in dealing with requirements builds up
early in the project.
reqts rigidity
•
Stability of requirements in later phases
is essential to minimize programmatic
impact
Short early
period of design
freedom
time
•
Re-using many requirements from other projects for later adaptation is not
recommended; better to focus at the beginning on the few key specific mission
requirements.
Carlos Corral van Damme | SECESA 2016, Madrid | 07/10/2016 | Slide 11
ESA UNCLASSIFIED – For Official Use
Early mission concept definition:
interfaces
•
Institutional missions often involve a complex organizational set-up.
•
Every time the system is decomposed and a part of it (i.e. subsystem) is
assigned to an entity, an internal interface is created.
•
Although system decomposition is often constrained by non-engineering aspects
(e.g. geographical considerations), subsystems should be defined so as to be as
independent as possible. This allows having:
•
Simple, clear and robust (stable) interfaces
•
Parallel subsystem development and testing
•
Interface definition for subsystems in development should be early managed by
an interface requirements document (ICD comes later).
•
Frequent interface technical meetings (working meetings) among the
different parties are essential to define and consolidate the interfaces
Carlos Corral van Damme | SECESA 2016, Madrid | 07/10/2016 | Slide 12
ESA UNCLASSIFIED – For Official Use
Systems engineering throughout the
project phases
Early phases
Later phases
•
Focus on understanding +
exploring + designing
•
Focus on solving problems and
getting things done
•
More abstract, theoretical
•
More tangible, practical
0
B
A
C
D
E
Systems engineering attitude/perspective needed
throughout entire project
Important benefits when team members can participate in both early and late design phases
Early-phases engineers provide a living
memory of the initial mission trades ⇒
important to assess the criticality of issues
and select the best solution.
Carlos Corral van Damme | SECESA 2016, Madrid | 07/10/2016 | Slide 13
ESA UNCLASSIFIED – For Official Use
Later-phases engineers provide
experience, mainly from problems
encountered in the past, and
verification & validation issues.
Conclusion
•
CHEOPS was selected in Oct 2012 as a test case for future ESA small-class
science missions.
•
The strict small-class mission implementation requirements have posed
significant challenges, calling for some specific project implementation solutions
(e.g. industrial procurement approach, project organization, etc.)
•
The experience from CHEOPS highlights the importance of early mission
assessment and the benefits of concurrent engineering.
•
CHEOPS is currently targeting launch readiness in the second quarter of 2018.
•
The support of all parties involved in the project is gratefully acknowledged.
Carlos Corral van Damme | SECESA 2016, Madrid | 07/10/2016 | Slide 14
ESA UNCLASSIFIED – For Official Use