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

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 9th November 2005 EGOS Workshop 2005

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 9th November 2005 EGOS Workshop 2005

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 9th November 2005 EGOS Workshop 2005

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

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

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 9th November 2005 EGOS Workshop 2005

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 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 9th November 2005 EGOS Workshop 2005

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

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 A Data Flow: Message A Function B Information Object Y Information Object X Data Flow: Message B 9th November 2005 EGOS Workshop 2005

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 Object Object Object View Service Provider Service Consumer Events Operations 9th November 2005 EGOS Workshop 2005

Mission Operations [MO] Services MES GSUS Other 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 PRQ FDS DPM OSM SRI GDD MCS REP MC SLE-Man SEX LOC TIM OPI PEX AUT Spacecraft M&C Proxy OB Schedule Proxy OB Procedure Proxy OB Data Product Proxy OB Software Proxy GSTS Spacecraft OB Data Product Storage Spacecraft M&C OB Procedure Execution OB Schedule Execution OB Software 9th November 2005 EGOS Workshop 2005

GDSS Mission Operations Services ID Name Description MC Core Monitoring & Control Parameters: publish status; set Actions [Commands]: publish status; invoke/send Alerts [Events]: notify; raise AUT Automation Specialisation of MC for automation of proxy functions DPM Data Product Management Data Product [Payload Data File]: directory; transfer FDS Flight Dynamics Orbit/Attitude: determination, propagation, manoeuvre preparation GDD Generic Data Dissemination Product: catalogue; order; deliver LOC Location Position: tracking, ranging, onboard positioning OPI Operator Interaction Message/Alarm/Query: notify; operator response OSM OB Software Management On-board Software: load; dump PEX Procedure Execution Procedure/Function: control; progress reporting PRQ Planning Request Planning Request: request; response RBM Remote Buffer Management Buffer: catalogue; retrieve; clear REP Report Reports: publish; catalogue; retrieve; generate SEX Schedule Execution Schedule: distribute; edit; control; progress reporting SRI Software Reference Image On-board Software Image/Patch: distribute TIM Time Time: report; set; correlate; notify 9th November 2005 EGOS Workshop 2005

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. 9th November 2005 EGOS Workshop 2005

The Service Model and Generic Structure Service Consumer Service Provider Service Directory Invoke Lookup Publish Service Versions Capability Sets 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 9th November 2005 EGOS Workshop 2005

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

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

Service Layering Stack of Layered Services or Protocols Kali mera ?!! 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 9th November 2005 EGOS Workshop 2005

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

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

Common Interaction Patterns Service Layer Service Provider Service Consumer Observe Control Manage Archive Service History Archive Retrieve Replay Control Replay (Observe) Service Configuration Database M C 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 9th November 2005 EGOS Workshop 2005

Conclusions Benefits of SOA Common Layer Granularity of Services 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 9th November 2005 EGOS Workshop 2005

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