1. Data Exchange and MBSE Developments for Space
Hans Peter de Koning (ESA/ESTEC, Noordwijk, The Netherlands)
Harald Eisenmann (EADS/Astrium Satellites, Friedrichshafen, Germany)
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

2. Intergovernmental organisation
European Space Agency
Intergovernmental organisation
18 member states
Annual budget around 3 billion €
Approximately 2000 staff
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

3. Moving towards Model Based Systems Engineering
Topics
Moving towards Model Based Systems Engineering
Standardization
INCOSE & OMG: SysML
ECSS: "Engineering Database" ...
R & D
Studies to validate standardization approach
Virtual Spacecraft Design
Space Thermal Analysis Model Exchange
Status STEP-TAS implementations
Geometrical models and space mission apects
Thermal test results
New development
Conversion between ESATAN, SINDA/FLUINT, SINDA/G
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

4. What is Model Based Systems Engineering? (INCOSE definition)
Model-based systems engineering (MBSE) is the formalized application of modeling to support system requirements, design, analysis, verification and validation activities beginning in the conceptual design phase and continuing throughout development and later life cycle phases
"INCOSE SE Vision 2020" INCOSE-TP Sep 2007
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

5. European space industry Current approach and status
Space system development process
Overall system engineering process well established – applied on all ESA projects
Standard: ECSS-E-ST-10-1C "System engineering general requirements"
All domain (discipline-specific) processes are well established – applied on all ESA projects
Avionics, power, structures, mechanisms, thermal control, propulsion, optics, software (on-board, groundstation), communication, control (orbit & attitude, robotics),
Project management, cost, risk, logistics, product assurance, …
Each with own ECSS standard
Tools
Domain disciplines are well supported in terms of engineering and analysis tools
For some disciplines there is excellent integration of design and analysis tools
Lack of support for system engineering: System level design is typically defined with office tools
System level design is “scattered” in different tools – with little traceability
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

6. Industrial Practice Limited Model Based Capabilities
Current industrial practice:
Many elaborated tools (analysis) and databases in use
Pragmatic bottom-up integration of particular tool chains
Many ad hoc databases
System level design status – by system modeling
Very good representation in phase 0/A (parametric models – standardized set of properties)
Requirements specifications partly in databases (RE Tools), partly in documents, some traceability
Very good representation for some disciplines (e.g. MCAD)
Phase B representation often kept in MS-Office products
System modeling is often driven bottom-up (e.g. flight software or simulation)
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

7. Trend: System Engineering "V" with Model-based Validation & Verification
Mission Need
Phase A
Phase B
Phase C
Phase D
Phase E
Feasibility Study
Conceptual Design
System / Preliminary Design
Detailed Design
Manufacturing
Assembly
Integration
Verification
Deployment
Validation
Top-Down Design
Bottom-Up Production, V&V
(Development &
Qualification)
Early V&V
Early V&V
Executable Model-based Validation & Verification
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

8. Model Based (System) Engineering Expected benefits
Systematic application of models for specification, design, verification and validation
Both for structure and behavior of the system
Managed traceability between all aspects and integrated version/configuration control
Expected benefits of consistent application of models
As much as possible single source data – generate/transform where possible
Allows computer aided completeness, consistency and quality checking
Improved collaboration between disciplines and organisations
Multidisciplinary teams
Efficient and reliable communication through supply chain
Eases development iterations and change impact analysis
Enables and promotes knowledge capture and (re-)use
Enables multiple, concurrent views (subsets, presentations) on same data
Reduced “manual” work and thus improve cost, schedule and quality / reduce risk
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

9. Comprehensive system level design representation
Ultimate Goal – MBSE
Comprehensive system level design representation
Seamless data traceability from system level design into domain engineering design
Consistent “transformation” from system design model into analysis (executable) model
For domain analysis models
System simulators
Consistent representation of the decision making process (analysis  design  verification)
Continuous verification / validation based on consistent application of virtual models
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

10. Enabling Technologies
Overall Integration Framework required
For efficient tool integration
For data exchange and sharing
To ensure common and mappable semantics
Specification of the required data
In a formal way on a conceptual level – ref. OMG/MDA PIM (Platform Independent Model)
Enabling subsequent “generation” of required implementation technology
System level design editors
Definition, modification and presentation of engineering data
Capturing properties and values
Supported by open standards
Cannot and want not standardize on tools
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

11. Supporting standardization and R&D
ECSS-E-TM "Engineering Database"
Technical Memorandum evolving to a future standard
Conceptual data model defining precise common semantics
MBSE reference architecture – using OMG/MDA principles
Re-use from STEP-NRF: formalized representation of quantities, units, dimensions, …
As much as possible aligned with SysML
ESA funded R&D
Space System Reference Model
Prototyping of centralized services as integration platform – validation of E-TM-10-23
Virtual Spacecraft Design
Demonstration of a space system engineering process relying on a virtual representation
Design Resource Center
Design data library to ease access
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

12. ECSS = European Cooperation for Space Standardization
Initiative started in 1995 to produce a coherent, single set of user-friendly standards for use in all European space activities
Previously there were different ESA and national space standards
Partners are space industry (via the Eurospace association), ESA and national space agencies
Published standards freely available from in PDF (after a simple registration procedure)
Complete update per March 2009
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

13. ECSS E-TM-10-23 "Engineering database"
Conceptual data model standard
Purpose: to provide common semantic reference for all engineering data repositories needed to develop and operate a space system through the whole life cycle
Defined using UML2 (class diagram)
Looking at simultaneous specification in ontology language (OWL, ORM) and EXPRESS
First release imminent
Expected May/June 2009
Will be published in hyperlinked wiki form to allow efficient review and evolution (generated from OpenAMEOS UML tool)
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

14. ECSS E-TM-10-23 "Engineering database"
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

15. ECSS E-TM-10-23 Adoption of the ECSS global conceptual data model for a project
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

16. Aligned with E-TM-10-23 (subset) Agreed list of reference data
ECSS E-TM-10-25
ESTEC CDF
Technical Memorandum to agree the exchange of conceptual design models (Phase 0 / A) between concurrent design facilities
Aligned with E-TM (subset)
Agreed list of reference data
List of design parameters with responsible discipline (~600 parameters)
List of recognised disciplines
Basic system decomposition
First release expected May/June 2009
Supported by OCDS (Open Concurrent Design Server) replacing Excel based infrastructure
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

17. Space System Reference Model
Integration Platform
SSRM Tool Connectors
SSRDB
Connector
SSRM Database
SSRM Tools
ATV Tools
ATV
SSRM
Control WS
Engineering WS
Business Logic
Basic S y s t e m E n g i r C o l G U I
Prototype an architecture on the SOA principles providing
Dedicated tool integration adaptors
Data management ‘procedures’
DB adapter to a RDBMS
Validate the approach on how ETM-10-23A model is defined with respect to
Evaluation of data modeling techniques
Comparison to existing data models (i.e. STEP AP’s)
Adequacy of data model to facilitate MDA development process
Develop and demonstrate a prototype with an industrial scenario
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

18. Space System Reference Model
Objective
Prototype physical and semantic integration platform
Validation of draft E-TM data model w.r.t. STEP, MDA compatibility
Demonstration based on real industrial scenarios
Result
Centralized webserver hosts shared applications like: adaptors, core application, version control, …
Persistent storage of data in RDBMS
Control applications
MDA based development framework
Status
Study successfully finished in May 2008
Results will be evolved in Virtual Spacecraft Design
Prototype an architecture on the SOA principles providing
Dedicated tool integration adaptors
Data management ‘procedures’
DB adapter to a RDBMS
Validate the approach on how ETM-10-23A model is defined with respect to
Evaluation of data modeling techniques
Comparison to existing data models (i.e. STEP AP’s)
Adequacy of data model to facilitate MDA development process
Develop and demonstrate a prototype with an industrial scenario
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

19. Design Resource Center
Objective
Development of design data library
Definition of equipment properties (used for design)
Result
Web-server application for the core application
HTML front-end integrated in ESA portal
Underlying relational database
Linkage to ESA DMS
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

20. Virtual Spacecraft Design
Objectives
Demonstration of a model-based system engineering process using a full virtual representation of the space system
Status - End phase 1 Requirements analysis and conceptual design
Overall process analysis performed
Use case analysis and user requirements specification performed
Overall architecture defined  lower level elements identified for prototyping
Next step – Phase 2 realization and demonstration (2009 – 2010)
Space System Design Editor
Space System Reference Database
Space System Visualization Tool
Builds further on E-TM-10-23, SSRM centralized integration platform, MDA for design editors, STEP-NRF
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

21. Virtual Spacecraft Design
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

22. Space System Engineering Repository
Overview Data Bases
Input by domain Administrators
Handling of Data via Eng. Tool
Supplier
ASTRIUM
S/C Eng. Reference
Customer
Space System Engineering Repository
SEDB
SDB
(TM/TC)
MCAD DB
(CAD Model)
CC DB
= SCC DB
EPPD
Equip. Physical Props.
SRDB
MCAD
Tool: CATIA
ECAD
Tool: Eng. Base
SimDB Tool: SimDB
SCOE TM/TC DB
AP DB Tool: MOIS
FDDB
Unit/ Equipment-SDB
AIT SDB
OBSW SDE
AOCS OSE Tool: Matlab/ Simulink
Parts/ Struct./ Harness Manufact.
El.Test Tool
Tool: IDAS
IDAS DB
Control Console
Tool: SimOps/ OpenCenter
EGSE DB
MDVE Simulator
EGSE DB
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009
Development & Verification Tools

23. Example validation of E-TM-10-23 in prototype space system design editor
Eclipse (Ganymede) based tool
Using GMF and EMF
Code generated from E-TM-10-23
data model using MDA approach
Developed by ScopeSET (Germany)
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

24. Example validation of E-TM-10-23 in prototype space system design editor
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

25. Support SysML RTF 1.2 and 2.0 work through INCOSE/OMG
Support to SysML
Support SysML RTF 1.2 and 2.0 work through INCOSE/OMG
Upgrade of Quantities, Units and Dimensions – foundation for SysML "value properties"
Now based on International Vocabulary of Metrology by BIPM
Combined concepts and lessons learned from ISO , STEP-NRF, MARTE, ontologies
Fully supports multiple quantities and units systems
Using new ISO/IEC standard (harmonised replacement of SI) as main reference
Integration of SysML Parametrics and Modelica
Modelica is a neutral language to define object oriented non-causal simulation models see
Powerful definition of executable (high level to detailed) system models
Mathematical equations relating properties at ports of blocks
With or without predefined causality (order of variable assignment or expression evaluation)
Fits well with SysML contraint blocks
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

26. STEP-TAS progress 11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

27. STEP-TAS Activities in 2008
IITAS – Industrial Implementation of STEP-TAS – in progress
ESA completed full test suite with automation tools
TASverter by ESA TEC-MTV (Thermal analysis and verification section)
Now more than 150 different users (2~5 downloads per week)
Routine use in many projects
Under maintenance – but very few bugs reported
Evolution of Expressik to support code generators STEP EXPRESS to C++ and Python
Evolution mapping STEP data into HDF5 format
Completed ESATAP v1 thermal analysis post-processor using STEP-TAS in HDF5 format
First validation of STEP-TAS Kinematics and Mission Aspects (CC2, CC4, CC5, CC6)
Implementation in TASverter for ESARAD
Proof of concept implementation in DynaWorks® for import of STEP-TAS analysis predictions
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

28. Started IITAS-TMG activity with Maya (Canada)
In progress 2009
Started IITAS-TMG activity with Maya (Canada)
Implementation of STEP-TAS import/export into TMG
Completion of IITAS and IITAS-TMG
Emphasis on testing and obtaining robustness of imports/exports
Full validation of STEP-TAS Kinematics and Mission Aspects
Implementation of full ESATAN / SINDA conversion in STEP-TAS and TASverter
Formalisation of STEP-NRF/TAS under ISO TC184/SC4
Was planned for 2008 but put on-hold due to lack of resources – shifted to 2009
R&D "Innovative methods for improved thermal testing"
o.a. using STEP-TAS to interface between analysis prediction and test results
Consolidate support software and test suites as true open source software
Depending on ESA open source software policy that is currently being finalised
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

29. ESATAN / SINDA conversion using STEP-TAS
ESATAN, SINDA/FLUINT, SINDA/G are major space thermal analysis tools
Old style FORTRAN finite difference / lumped parameter solvers
Common heritage to CINDA which was developed in 1960s
Used on many space projects worldwide
Model defined in two parts: DATA and OPERATION blocks
DATA blocks define model structure: nodes, conductors, boundary and initial conditions, ...
OPERATION blocks define behaviour simulation: user defined logic and solver calls
Quite sophisticated modelling capabilities for active thermal control: thermostats, PID controllers, heatpipes, fluid loops, evaporators/condensors, Peltier elements, mission (power) mode switching, model parameterization, non-linear material properties, ...
Exchange of DATA blocks is supported by existing tool-to-tool converters
But incomplete and not reliable
Exchange of OPERATION blocks is manual: very complicated and time consuming
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

30. Data exchange implementation ESATAN / SINDA OPERATION blocks
ANTLR ( is a
very powerful OSS lexer/parser package.
JSON ( is JavaScript Object Notation, a very powerful but simple serialization format supported by OSS in almost all programming languages.
Use ANTLR to parse ESATAN or SINDA MORTRAN language
Store resulting abstract syntax tree in prefix notation using JSON
For expressions we use the Content MathML approach
Only not in XML but JSON encoding
e.g. "X = 4.0 * ( )" → ["assign", "X", ["times", 4.0, ["plus", 2.0, 3.5]]]
For algorithms (sequence of statements, if-elseif-else blocks, loops, etc.) we use simple keywords
e.g. ["loop_for", loop_var, start_expression, end_expression, step_expression, statement_block]
Integrated into STEP-TAS through EXPRESS ENTITY instances
nrf_algorithmic_language, nrf_algorithmic_expression, nrf_algorithmic_statement
Both in neutral JSON language and original ESATAN or SINDA language
Prototypes work very well
Perhaps interesting light approach also for other algorithm conversion need
Upgrade of TASverter expected later this year
Development contracted to DOREA (France)
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009

31. European Space Agency http://www.esa.int
References
European Space Agency
Astrium Satellites
European Cooperation for Space Standardization
SysML – Systems Modeling Language
STEP-NRF and STEP-TAS Look for "Standards”
TASverter Look for "TASverter“
ISO TC184 / SC4 standardization committee (a.o. STEP standards)
11th NASA-ESA Workshop on Product Data Exchange
29 April - 1 May 2009