[Sea-sa] Request for SEA-SA review of SOIS / MOIMS analysis document

Shames, Peter M (312B) Peter.M.Shames at jpl.nasa.gov
Thu Oct 25 21:48:59 UTC 2018

Dear SAWG members,

During the joint SAWG / MOIMS / SOIS meeting on Wednesday we spent quite some time discussing the draft document that SOIS produced comparing MO Services (based on the MAL) and SOIS EDS.  This is a Yellow Book, CCSDS 870.10-Y-0, titled "MO SERVICES AND SOIS ELECTRONIC DATASHEETS".  The MOIMS AD identified a series of conditions that were written into the body of the PDF.  It did not appear that the MOIMS and SOIS were going to reach agreement on the disposition of these comments without some help, so I volunteered to provide an analysis on behalf of SEA.  I want to enlist you in making sure that this is fair and balanced.

I am also adding Richard Melvin and Sam Cooper to this list, since Richard was the author of the document and Sam was the primary MOIMS point of contact.  I ask them to put their "SAWG hats on" and participate in as unbiased a way as they are capable of, while offering any technical clarity and accuracy is needed.  In this they are supplemented, of course, by Roger and Ray.

The first thing to say about this analysis is this:

  1.  We have the ASL document and our own analyses and discussions of the suite of standards to draw upon
  2.  We have agreed, among ourselves and in this joint meeting, that there are three stages of MOIMS deployment into the on-board environment

Both of these are background and criteria for providing feedback.  The three stages were stated during the joint meeting and they are repeated here for reference:

  1.  SOIS device interfaces, subnets, and services on-board with the usual Real Time flight software and resource constraints, MOIMS only on ground, typical TT&C interfaces between them
  2.  Same SOIS services and RT FSW on-board, MOIMS Proxy interfaces to RT FSW on-board, "MAL" interfaces over TT&C
  3.  Same SOIS services and RT FSW on-board, MOIMS MAL adapted to RT environment and "standard" MOIMS services migrated on board as appropriate
Attached is the modified draft CCSDS 870.10-Y-0 document, in PDF form.  It has three kinds of notes in it:

  1.  Notes that show up as a white square came from MOIMS
  2.  Notes that show up as a yellow square with a "thought bubble" also came from MOIMS
  3.  Notes that show up as a magenta square, are comments from me as to responses and rationale
  4.  Notes that show up as a red square are suggested changes to the draft document, many in response to MOIMS issues, some reflecting issues I found in reading the document
You will see that I recommend adding text to reflect the three stages we have agreed to, even though that is new material from the SAWG.  I think it will help to clarify the options relating to deployment.  Some of the MOIMS comments attempt to push boundaries and I suggest that not be allowed.  Existing scope, functions, and standards are to be respected. Some MOIMS comments propose on-board services, like MO compliant device interfaces, that are very speculative.  I think that they should be labelled as such since there are no MOIMS documents that can be referenced.  The current work in SOIS to define use of EDS to document deployments of components and spacecraft configurations, however, is within scope since they are actively working on that.  I also found that this document, in general, is lacking a recognition of the importance of specifying interface bindings along with behaviors and data structures.  I recommend that it gets added.
Please review these MOIMS comments and my proposed dispositions.  I would like to have your feedback in two weeks, by 9 November, if not sooner.  This has dragged on long enough.  Assuming we can reach consensus I will then send the final result to the combined MOIMS and SOIS teams.   I will provide final edits to the document in Word form once we have closure.
While we are working together to reach consensus I ask that you all treat these materials, and the discussion, as SAWG internal work product.
Thanks, Peter

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