2nd ESA Astrodynamics Tools & Techniques workshop

M. Schön ESA/ESTEC 1

The Virtual Spacecraft Reference Facility

M.Schön, M.Arcioni, D.Temperanza, K.Hjortnaes

Michael.Schoen@esa.int

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 SchönMichael.Schoen@esa.int

On-Board Software Systems Section

Q&A