2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC 1
The Virtual Spacecraft Reference Facility
M.Schön, M.Arcioni, D.Temperanza, K.Hjortnaes
On-Board Software Systems Section
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
Agenda
• Why?• What?• How?• When?
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
The Virtual Spacecraft Reference Facility – architecture view
EuroSim
Power
Thermal TCP/IPS-band
Mass Memory
X-band
SVF
clk
SV
F to
ols
TM/TC Front End
TM/TC
TM/TC
Mis
sion
Dat
aBas
e
Avionics
OBSW
Payload
Environment
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
The Virtual Spacecraft Reference Facility – user view
EuroSim
TCP/IP
SVF
clk
SV
F to
ols
TM/TC Front End
TM/TC
TM/TC
Mis
sion
Dat
aBas
e
Matlab:-S/C dynamics-Environment-Avionics-Power
MOSAIC
EuroSim:-Payload-S/C subsystem(e.g.Thermal)
SVF:-simulation engine(tsim) (or SHAMboard) runningOBSW
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
The problem
• Many of the R&D activities on software tools or software components never reach the needed maturity level due to lack of validation in a representative Spacecraft Environment.
• Example:Company A develops a new method for dynamic analysis of on-board software. The study is on the method but it requires a “real on-board software” test case to prove its value. The “hello-world” test case is not sufficient nor convincing.
• Key requirement: “Validation in context”
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
Example: Mars Pathfinder
• July 4th 1997• Problem: Random system resets• Cause: Priority inversion
Ref:www.cs.cmu.edu/afs/cs/user/raj/www/mars.html http://www-cs.cmu.edu/afs/cs/user/raj/www/mars.htmIEEE Real-Time Systems Symposium (4 dec 97) David Wilner, Chief Technical Officer of Wind
River Systems. (Wind River makes VxWorks)
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
Why does this happen?
1. Validation not performed in Context2. Validation in a simplified environment or by
similarity is simply not good enough3. Models are an approximation
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
Where in the process does it go wrong?Technology Readiness Levels- The missing links
1. Technology Concept and/or application formulated2. Analytical and experimental critical function and/or characteristic
proof-of-concept3. Component and/or breadboard validation in laboratory
environment4. Component and/or breadboard validation in relevant
environment5. System/subsystem model or prototype demonstration in a
relevant environment (ground or space)6. System prototype demonstration in a space environment7. Actual system completed and “Flight qualified” through test and
demonstration (ground or space)8. Actual system “Flight proven” through successful mission
operations
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
Objective
• Develop a Virtual Spacecraft Reference Facility that provides a simulated spacecraft context suitable for demonstrating and validation of R&D results.
• The VF-RF shall be modular such that it is suitable for creating a software test bench with all simulated devices or an avionics test bench with hardware-in-the-loop.
• It shall be a moving target
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
Stake holders
Technology validation with the following cross domain undertakings:
• On-board Software • Simulation Technologies• Data Handling • Avionics• Software engineering and Standardization • Ground Support Equipment
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
Potential Experiments
• Software Framework initiatives• SOIS• Bus protocol stacks (SpaceWire, 1553 …)• Autonomy initiatives• AOCS (algorithms, model, autocode ….)• Simulation Model interface standardisation effort• Software development methods & tools• Test tools (SCOS-2000, SDB, Pluto …)• Mass Memory experiments
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
Starting point.
• Based on tailoring of already developed on-board software, environment simulation models, Software Validation Facility, etc. create a Virtual Spacecraft Reference Facility
• Elements (but not limited to)– OBOSS Packet Utilization Standard Library– AOCS framework– Eurosim– SVF– Visualization Software– SCOS-2000
• The VS-RF shall continuously be evolving to include new developments. (Moving Target)
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
VS-RF’s
• Version 1: All software implementation of the Virtual spacecraft;
• Target: software validation (simulated real time).
• Version 2: Iron bird / avionics test bed• Target: Hardware In the Loop
Communication bus implementations (e.g. 1553, SpW)
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
The VS-RF v1
• Mission definition:– Mission Requirement document (simple polar orbit)– Defined command and control services (G/S ICD)– Spacecraft Architecture
• Implementation– Data management software (running on RTEMS/ERC32).– AOCS software– Environment simulation (avionics devices, dynamics)– Environment simulation infrastructure – Software validation facility– COTS tools
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
Mission Requirement -The EagleEye Mission
• The mission drives the requirements.• Characteristics:
- 250 kg- Low Earth Orbit (Sunsynchronous , α=7050km, i=98.2°)- Payload: High Resolution Imaging Camera- Mass memory 80 Gbit- One ground station (Svaalbard)- S-band link: 2 kbps up and 4 kbps down- X-band link: 100 Mbps.
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
Virtual Spacecraft Architecture -The EagleEye Mission
.
GoldenEye
Payload Data Management System
RF Communication
SSMM
CDMU
X-band
S-band
Battery
PCDU
Solar ArrayPower subsystem AOCS subsystem
sensors
GPS
Star tracker
Gyros
Sun Sensor
actuators
Thrusters
Heaters
Temp. sensorsThermal subsystem
serial / 1553 RT
serial
1553 RT
analog
1553 BC
1553 RT
1553 RT
High Speed Link
1553 RT
1553 RT
1553 RT
Magnetometeranalog
Magnetorquer
Reaction Wheels
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
VSRF User Interface 1/2
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
VSRF User Interface 2/2
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
What makes the VS RF different from other testbenches?
• It is an infrastructure concept, not only a set of tool(s), It is a moving target
• A Technology Validation process applied to it.• Targeted for Technology Validation• Open System; OBSW, Models, SVF are open source
with standarized interfaces (*1). Mostly non proprietary infrastructure elements.
*1) Under license agreement with ESA
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
Implementation - Workflow
DMS OBSW<ID#1>
AOCSControl aw
<ID#2>
OBSWIntegration
<ID#7>
VSRF simdesign<ID#3>
DH (SVF)Models<ID#4>
Toolsmodification
<ID#5>
TM/TCdatabase<ID#6>
EuroSimIntegration
<ID#8>
SVFIntegration
<ID#9>
VS-RFintegration<ID#10>
Dutch Space
Simulink models
AOCS ICD
Sener
TERMA
•AOCS Control Law Sener (ES)
•OBSW and SVF Terma (DK)
•Integration and EuroSim modelsDutch Space (NL)
•AOCS Simulation modelsESA
•Status: Kicked off in Januari 2004.Finished end of this year
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
Organisation
• A small budget was available for tailoring contracts to get the thing going.
• Sustainable investment funding is requested for the coming years.
• Particular study configurations are not covered by the VS-RF budget, i.e. the experimenter (R&D contract) pays for his own experiment.
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC
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Virtual Spacecraft Reference Facility
Summary
• The Virtual Spacecraft Reference Facility is an infrastructure to be used for demonstrating and validation of R&D results.
• Validation in context!• It will continuously be developed (through industrial contracts) to
satisfy requirements from the stakeholders domains:- On-board Software, - Simulation Technologies- Data Handling- Avionics- Software engineering and Standardization- Ground Support Equipment
2nd ESA Astrodynamics Tools & Techniques workshop
M. Schön ESA/ESTEC 23
The Virtual Spacecraft Reference Facility
Michael Schö[email protected]
On-Board Software Systems Section
Q&A