1. 1 CCSDS Architectures: Issues and Proposals October 2010 London, UK Takahiro Yamada, JAXA/ISAS

2. Issue 1  There are multiple CCSDS documents that specify an architecture:  Reference Architecture for Space Data Systems (RASDS) (SE-SAWG)  Reference Architecture for Space Information Management (SE-IAWG)  Space Communication Cross Support Architecture (CSS- CSAWG)  Solar System Internet Architecture Description Document (IOAG)  Cross Support Reference Model (CSS)  Mission Operations Architecture (MOIMS-SMCWG)  Spacecraft Onboard Interface Architecture (SOIS)  Overall CCSDS Architecture (CSS-RASIG) 2

3. Issue 2  Some of these books define viewpoints according to IEEE 1471 or ISO 42010.  Should all of the viewpoints be defined in a single document? If so, what document should define the viewpoints?  Should each of the documents define the viewpoints that are necessary in the document? If so, how can we maintain consistency among different viewpoint definitions? 3

4. Issue 3  Where are the boundaries among different sets of services?  Where is the boundary between space communication services and mission operation services? Where does SLE SM belong to?  Where is the boundary between space information management services and mission operation services?  Where do the SOIS services belong to?  Where should these boundaries be defined and documented?  Services must be defined in terms of their relationship with other sets of services. 4

5. Proposal 1  We need to define categories of services.  Based on the defined categories of services, we should define a hierarchy of architectures, including a top-level architecture and sub-architectures, each for a category of services.  There should be a document for each of the architectures.  In the top-level architecture document, we should define categories of services and the hierarchy of architectures.  Without this top-level architecture document, we should not continue working on sub-architectures. 5

6. Hierarchy of Architectures (Example) 6 CCSDS Reference Architecture: Defines categories of services and the hierarchy of architectures RASDS: Defines a methodology Onboard Service Architecture A B Shows that B depends on A End-to-end Service Architecture Ground Service Architecture Space-Ground Service Architecture

7. Proposal 2  We should create a super SIG, which will have a member from each of the WGs developing architectures (CSA, SMC, IAWG, SOIS, etc).  Presently RA-SIG consists of people recommended by the Agencies and they do not necessarily represent WGs.  Resources should be available because there are resources to develop architectures in the WGs. 7