1. www.scisys.co.uk EGOS Workshop 2005 GDSS - Ground Data System Services: a Service Oriented Architecture for Mission Operations Roger Thompson, Nestor Peccia, Stewart Hall, Oliver Page Presented by: Roger Thompson

2. EGOS Workshop 2005 9th November 2005 2 GDSS Study Context Definition of Standardised Ground Data System Services  Study for ESA/ESOC commenced in 2004:  Considering Service Architecture for EGOS Infrastructure  Builds on Reference Architecture developed in context of European GS Technology Harmonisation  Builds on Mission Operations Service Framework being developed by CCSDS Spacecraft M&C Working Group  Study Outputs  GDSS Service Framework document  Draft Specifications produced for:  GDSS-C Common Service  GDSS-MO Core M&C Service  GDSS-MO Schedule Execution Service

3. EGOS Workshop 2005 9th November 2005 3 GDSS Objectives  Definition of a Service Oriented Architecture for the Mission Operations domain  Focussed on Ground Segment, but capable of extension to Check-out and Space Segment  Compatible with evolving CCSDS SM&C Standards  Standardised Services enable:  Open Interfaces between Major Components  Development of Re-usable [and Replaceable] Plug-in Components  Rapid Mission Specific Deployment  Isolation of Domain Software from Deployment Technology  Legacy Software to be wrapped for Re-use

4. EGOS Workshop 2005 9th November 2005 4 CCSDS Context  See Presentation by Mario Merri  CCSDS Spacecraft M&C Working Group  MOIMS Area WG, Established October 2003  Active Participation from ESA, BNSC, CNES, CSA, DLR, JAXA and NASA (JPL, GSFC)  Mission Operations Services: end-to-end Application level services for spacecraft operations interactions  Current Status  Mission Operations Service Framework available  High Priority Service Specifications in production  SM&C Core, Common and Protocol Layers  Early work on other Service Specifications  Prototyping of High Priority Services about to start

5. EGOS Workshop 2005 9th November 2005 5 Integrated Systems vs. Modular Components

6. EGOS Workshop 2005 9th November 2005 6 Service-Oriented Architecture: Plug-in Components Components Services Infrastructure

7. EGOS Workshop 2005 9th November 2005 7 Benefits of the SOA Approach  Components exchangeable for others supporting same Service Interfaces  Plug-and-play interoperability of MCS components  Common Service Framework  Re-use of common infrastructure across multiple systems  Independence of mission configuration data and history from system implementation  Infrastructure Implementation can be changed without change to core Applications  Independence of core application software from underlying implementation technology – platform and communications  Components rapidly deployable in different combinations  Reduced mission-specific deployment costs  Extensible: easy to add new components  Scope to evolve a system, by replacing components or changing underlying technologies  Success is dependent on the Granularity of the service architecture selected

8. EGOS Workshop 2005 9th November 2005 8 Identification and Modelling of Services  UML-2 Model with different “Views” (cf. RM-ODP)  Functional View  Information View  Service View  [Multiple] Deployment Views: Physical Architectures  Functional View  Application Level Mission Operations Functions  Initial Selection based on ECSS and Ground Segment Harmonisation  Separation of Functions at Potential Distribution Boundaries: Space-Ground; Geographical Sites; Client-Server Differences in Cardinality (Scalability)  End-to-End Interfaces  Omits Data Transfer and Storage Functions  Point-to-Point; Defined by Interfaced Functions; Wire Protocols

9. EGOS Workshop 2005 9th November 2005 9 Mission Operations Functions MES: Mission Exploitation MCS: Mission Operations GSTS: Ground Station Network Spacecraft Station M&C GSUS: Ground Support System EGSE On-board Automation Ground Automation Tracking & Ranging AOCS Flight Dynamics Spacecraft M&C Operator Interaction Analysis & Reporting Mission Data Processing Mission Data Acquisition Mission Product Distribution External Data Distribution Operations Planning Station Scheduling Mission Planning On-board Software OB Software Development & Validation OB Software Management

10. EGOS Workshop 2005 9th November 2005 10 Information View  Same Information Type flows on Multiple Interfaces  Identify Fundamental Information Types for Domain  M&C: Parameters; Actions [Commands]; Alerts [Events]  Operator Interactions  Automation: Activities [Procedures]; Tasks ; Schedules  Planning Requests  Time; Position; Orbit & Attitude Vectors; Predicted Events  Software Images  Data Products; Reports  Identify Operations [Use Cases] that can be performed on these Information Types Function AFunction B Data Flow: Message A Data Flow: Message B Information Object Y Information Object X

11. EGOS Workshop 2005 9th November 2005 11 Service View  Interfaces: Point to Point, Data Flow Oriented, Full Protocol Stack  Services: Many to Many, Information Oriented, One Layer of Stack  Service Objects: represent Domain Specific Information  Event Messages synchronise the Consumer’s View  Control Messages allow the Consumer to invoke Operations  Each Domain Service has its own specialised Information Model  Generic Common Service: publish Events and invoke Operations Service Provider Service Consumer ObjectObject View Events Service Object Operations

12. EGOS Workshop 2005 9th November 2005 12 OtherGSUS MES Spacecraft GSTS MCS OB Data Product Storage Spacecraft M&C OB Procedure Execution OB Schedule Execution OB Software Tracking & Ranging Mission Planning Mission Data Processing External User Operations Planning Flight Dynamics Operations Automation Operator Interaction Station M&C Station Scheduling External Data User Analysis & Reporting OB Software Development OB Software Management Spacecraft M&C Proxy OB Schedule Proxy OB Procedure Proxy OB Data Product Proxy OB Software Proxy Mission Operations [MO] Services GDD LOC PEX SEX DPM AUT OPI OSM SRI FDS REP MC SLE-Man PRQ TIM

13. EGOS Workshop 2005 9th November 2005 13 GDSS Mission Operations Services IDNameDescription MCCore Monitoring & ControlParameters: publish status; set Actions [Commands]: publish status; invoke/send Alerts [Events]: notify; raise AUTAutomationSpecialisation of MC for automation of proxy functions DPMData Product ManagementData Product [Payload Data File]: directory; transfer FDSFlight DynamicsOrbit/Attitude: determination, propagation, manoeuvre preparation GDDGeneric Data DisseminationProduct: catalogue; order; deliver LOCLocationPosition: tracking, ranging, onboard positioning OPIOperator InteractionMessage/Alarm/Query: notify; operator response OSMOB Software ManagementOn-board Software: load; dump PEXProcedure ExecutionProcedure/Function: control; progress reporting PRQPlanning RequestPlanning Request: request; response RBMRemote Buffer ManagementBuffer: catalogue; retrieve; clear REPReportReports: publish; catalogue; retrieve; generate SEXSchedule ExecutionSchedule: distribute; edit; control; progress reporting SRISoftware Reference ImageOn-board Software Image/Patch: distribute TIMTimeTime: report; set; correlate; notify

14. EGOS Workshop 2005 9th November 2005 14 Service Definition  Platform Independent UML Model [Model Driven Architecture]  Includes:  Information View: defines Domain Level information common to Service Providers and Consumers  Service Configuration Data (e.g. for a specific Spacecraft) allows customisation of a Service Instance  Configuration Data is Open, not specific to Implementation  Service View: messages exchanged between Service Providers and Consumers  Service History/Logging allows for recording, retrieval and even replay of past Service Messages sequencing of messages  Expected Service Interaction, Error Conditions, etc.  Relationships: to other Objects in other Domain Services  Other Characteristics: Security, Quality of Service, Parallelism, etc.

15. EGOS Workshop 2005 9th November 2005 15 The Service Model and Generic Structure  Service Versions  Capability Sets Service ConsumerService Provider Service Directory Invoke LookupPublish Service Layer Service Provider Service Consumer HCI Displays Other Applications Service Configuration Database Service History Archive Service Editor Operations Preparation Invoke Archive History Service Directory Publish Lookup Configure Edit Active Service Interface

16. EGOS Workshop 2005 9th November 2005 16 Events and Operations: Parameter Example Service Layer Service Provider Service Consumer HCI Displays Other Applications Service Configuration Database Service History Archive Observe Control Manage Archive Replay, RetrieveAccess Parameter Class Parameter Object Definitions Parameter History Parameter Events Set Parameter Action Disable/Enable Monitoring Checks Dynamic History Replay: Observer view Block Retrieval

17. EGOS Workshop 2005 9th November 2005 17 Operations Execution Service Status Data Object Identity 11 Object Definition Concurrent Sessions (Live + Simulated + Replay) 1 1 Object Status Update E Operation O 1n Object Instance Instantiate O Generic Service Object Information Model Present Operations Analysis Service History Historical Sessions Object Identity 1n 1 n Object Definition Object Status Past Status Update Event Definition Update Event EE 1n Object Instance Instantiation Event E Replay E E E Operations Preparation Service Configuration Data Object Identity 1n1 Object DefinitionVersion Version Series Install Edit Save Validate Future 1 Retrieve EEE EEE EEE

18. EGOS Workshop 2005 9th November 2005 18 Service Layering  Stack of Layered Services or Protocols  Stack must match on both sides for Interoperability  Low-level Communication does not ensure Compatibility at the Application Level  ?!!

19. EGOS Workshop 2005 9th November 2005 19 Service Layering Application Level Services Common Services MO Domain Service Framework Consumer Application Provider Application MO Domain Specific Applications Technology Adaptors SAP: Service Access Point Plug-in Applications Infrastructure Services Message Exchange; File Transfer; Mail Technology Specific Infrastructure Communications Services

20. EGOS Workshop 2005 9th November 2005 20 Service Layering Application Level Services Common Services Consumer Application Provider Application SAP: Service Access Point Infrastructure Services Message Exchange; File Transfer; Mail Communications Services Technology Adapters

21. EGOS Workshop 2005 9th November 2005 21 Common Interaction Patterns  Common to multiple MO Services  Generic Service Elements implemented in Common Layer  MO Services “specialise” Generic Objects: define Attributes, Operations and Events  2 Principal Patterns: Operations and Product Distribution  Generic Infrastructure to Support all Services Service Layer Service Provider Service Consumer Observe Control Manage Archive Service History Archive Retrieve Replay Control Replay (Observe) Service Configuration Database MC

22. EGOS Workshop 2005 9th November 2005 22 Conclusions  Benefits of SOA  Flexibility / re-usability in mission architecture  Common Layer  Independence from technology  Granularity of Services  Achievable standardisation  SOA Modelling Guidelines  Guidance for future development  Community Review  Benefit of wide review by space system experts  Relationship to CCSDS Spacecraft M&C WG  Continue to track parallel work  Prototyping  Needed to prove / improve the service definitions  Extending the model  Management of future service definition work

23. EGOS Workshop 2005 9th November 2005 23 Recommendations 1.Build a Prototype of the basic MC service over the Common service as soon as possible 2.Embark on a study to develop the Event Archive (EARC) and produce a prototype implementation 3.Develop more service definitions, integrated with the service framework UML model 4.Continue to participate in / lead the CCSDS equivalent activities 5.Widely circulate the GDSS Study and encourage wide community review of subsequent work