XASTRO XML based data exchange framework for space programmes

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XASTRO - XML based data exchange framework for
space programmes
Niklas Lindman, ESA/ESOC, Niklas.Lindman_at_esa.int A
nthony Walsh, VEGA IT GmbH, Anthony.Walsh_at_vega.de
Dr Peter Ellsiepen, VEGA IT GmbH,
Peter.Ellsiepen_at_vega.de Marcus De Deus Silva,
VEGA IT GmbH, MarcusDeDeus.Silva_at_vega.de Space
Ops 2002 9-12th October, 2002
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Presentation Outline

• XASTRO Study Introduction
• Motivation for Study
• Study Logic
• Framework Overview Foundations
• Model Driven Architecture
• Current Data Exchange Frameworks
• Current Space Domain Mark-up Languages
• Use Cases
• XASTRO Status
• Summary

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XASTRO Study Introduction

• ESA study to investigate the use of XML as the
  basis for a standard data exchange framework
  between customers, contractors and suppliers
  during the life-cycle of a space mission
• XASTRO is a study project being executed under
  ESAs Innovative Technology programme as a
  potential solution to current data exchange
  problems
• XASTRO study duration 12 months and is being
  managed from ESA/ESOC
• Address data exchange for the procurement phase,
  integration of mission elements, mission
  operations, space product storage and retrieval
• Focus on space segment

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Motivation for XASTRO

• Data Exchange is difficult for many reasons
• Large quantity of information in a space mission
• Wide range of information types represented in a
  diverse range of formats, with little
  standardisation
• Many stakeholders geographically distributed
  (Space Organisations, Contractors, Scientists
  etc.)
• Information is generally document driven, i.e.
  the information is tightly coupled to how it is
  presented
• Mission budgets are continually being tightened
  leading to greater need for efficiency while
  maintaining acceptable levels of risk
• Too many ad-hoc solutions to data exchange from
  one mission to the next

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Study Logic

• Review current data exchange frameworks and
  mark-up languages (i.e. SML, IML, GSML, MDA,
  STEP) and related activities in OMG and CCSDS
• Propose a general data model framework to support
  space missions. Framework has two main elements
• Astronautics Reference Object Model (ASTROM)
  defined in UML
• XASTRO schemas (XASTRO is the XML based
  representation of the ASTROM UML model)
• Apply framework to candidate mission (CRYOSAT)
• High level analysis of whole mission
• Detailed analysis of most applicable domain
  candidates
• Develop prototype applications to test framework
• Summarise results and identify the way forward

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Framework Overview

• Define space system engineering framework that
  allows a common way to describe, store and
  exchange data, consisting of
• Astronautics Reference Object Model (ASTROM) - a
  Unified Modelling Language (UML) data model that
  describes the entities within a space system
• XML implementation of ASTROM (XASTRO) - a space
  data description and data interchange language
• Most investment will go into design of a
  conceptual model in UML. This model gives context
  to the XASTRO schemas.
• XASTRO schemas directly generated from the ASTROM
  (use of XMI and XSLT)
• Above approach is aligned with OMGs Model Driven
  Architecture (MDA)

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Framework Foundations

• XASTRO Framework Foundations support basic system
  engineering data concepts
• Hierarchical Decomposition
• Multi-Disciplinary Views
• Cross View Relationships
• Properties
• Behaviour
• External References
• Basic concepts taken from current standards /
  technologies (STEP, ADLs, MDA)
• Framework does not address all aspects of system
  engineering information - focus on structural and
  functional aspects of system
• Framework based on widely accepted open standards
  (XML/XMI, UML)

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Framework Work Flow
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OMGs Model Driven Architecture

• UML replaces CORBA as core model in OMGs world
• Platform Independent Models (UML, MOF and CWM)
• Standard mappings to Platform Specific Models
  (i.e. CORBA, EJB, .NET) which can include XML
  Schemas (e.g. XASTRO)

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Current Data Exchange Frameworks

• STEP AP-233 (ISO 10303-233) - The Standard for
  the Exchange of Product Model Data (STEP) is an
  international standard (ISO 10303) for exchanging
  data between different engineering disciplines.
  STEP AP-233 (ISO 10303-233) is working to create
  an international STEP-based standard for Systems
  Engineering Data Representation.
• ADLs - Architecture Description Languages are
  usually applied to model software architectures.
  However, the underlying principles and ideas are
  also relevant when modelling general system
  architectures consisting of physical components,
  software and hardware as is the case for space
  systems.
• OMG DSIG - OMG Systems Engineering Domain Special
  Interest Group (SE DSIG) is to support evolution
  of UML for Systems Engineering (SE)

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Some Space Domain Mark-up Languages

• SML - Aimed at providing a standardised
  representation of Spacecraft for use in
  spacecraft control systems. Developed by
  Interface Control Systems, Inc, Columbia,
  Maryland, USA
• IML/AIML - The Instrument Mark-up Language is a
  general language to describe instruments based on
  an XML Schema. Developed by NASA/GSFC and Century
  Computing
• GSML - Ground Segment Mark-up Language that
  provides a hierarchical command and control
  language that implements the virtual ground
  station (VGS) abstraction levels. Developed and
  applied at the Space Systems Development
  Laboratory (SSDL)
• XDF - The eXtensible Data Format is a common
  scientific data format. Run by the Astronomical
  Data Center, NASA GSFC. The NASA Astronomical
  Data Centre (ADC) has produced a spacecraft
  telemetry schema which extends XDF adding
  spacecraft telemetry data features to it
• OrbitML - Represents information objects in the
  spacecraft Flight Dynamics problem domain.
  Conceived by GMV, Spain.

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XASTRO Use Cases

• It is envisaged that the XASTRO language could be
  applied to a number of activities that are
  performed as part of a normal space mission. For
  example
• Space Mission Information Management
• Concurrent Engineering
• System Simulation
• Real-Time Data Exchange
• System Architecture Specification
• Documentation Production
• A number of prototype applications are being
  developed as part of the study

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XASTRO Status
XASTRO is an on-going study Whats the current
status?
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Summary

• Base XASTRO on open standards (UML, XML/XMI) with
  excellent tool support from many vendors running
  on many platforms
• Use ideas of existing frameworks when applicable
  (STEP, ADLs, MDA, etc)
• Avoid duplication of existing work
• Keep it simple - however XASTRO must be
  expressive enough to capture the semantics of the
  problem domain
• Test framework with practical examples -
  application to the Cryosat mission