[Sea-sa] Next telecon planning

Ramon Krosley r.krosley at andropogon.org
Tue Jun 6 17:38:02 UTC 2017

I was working on writing some of the material for the SAA green book, and came to the conclusion that there is an aspect of the material that we have not yet discussed.  We have seen the architecture of MOIMS, and we have pursued the architecture of SOIS.  We have even gotten a hint of parallel functions in Richard’s review of MO and EDS.  There still remains a gap in the overall interoperation between MOIMS and SOIS.

Roger mentioned recently that, if he could see the SOIS application support services, then he could talk about how MOIMS could use them.  I have some results from the Spring meeting that address this issue, which I’ll put into the meeting materials on CWE.  I think there is more to the interaction between these domains than the service interfaces, and that addition is the subject of this message.

If it seems reasonable to the group, here is a start on this gap, a potential topic in tomorrow’s teleconference.  The following is draft text for Section 1.1 in the SAA green book, for discussion.  I am probably doing an injustice by mentioning packet utilization standard, but Roger can set me straight on how that school of thought is represented in MOIMS.  The new topic introduced here is reuse of components on different platforms.  There may be other topics in the interaction of MOIMS and SOIS that I have missed.  This deviates slightly from Peter’s initial <<summary>>, so I want to test that possibility.


The purpose of this document is to harmonize the standards for mission operations with the standards for onboard interface services.  This harmonization must occur in two modes of operation.

*	Historically, onboard interface services have been a simple conduit at the space end of telecommands and telemetry, while mission operations has occupied the Earth end of those communications.
*	As missions move farther from Earth, mission operations inevitably will place applications onboard space vehicles, due to the increasing need for timely autonomous behavior in distant flight.

The packet utilization standard (PUS) has emerged as an organizing principle affecting data onboard a vehicle to serve the needs of Earth-based mission operations.  Within CCSDS, the MOIMS standards are developing to support increasing autonomy in flight.  SOIS must provide useful services in both modes of operation.

Another trend in space technology is an increasing need for economy in the infrastructure.  One manifestation of this trend is that reuse is replacing recurring engineering.  SOIS provides techniques for reusing hardware and software among projects and among agencies.  As the common denominator in the two modes of operation, the techniques provided by SOIS can increase the reusability of MOIMS applications.

This document reviews the architectures of MOIMS and SOIS in order to recognize how to harmonize communications and how to improve reusability.  As the first step in that review, the separate goals of MOIMS and SOIS appear below.  Recommendations for future collaboration appear at the end of this document.

1.1.1     Purpose of MOIMS

…to be written…

1.1.2     Purpose of SOIS

The fundamental purpose of SOIS is to provide communication between applications onboard a vehicle and the following categories of communication endpoints.

*	Devices onboard the vehicle
*	Other applications onboard the vehicle
*	Applications external to the vehicle

For communications with endpoints external to the vehicle, SOIS organizes onboard protocols as necessary to supplement external protocols provided by communication devices onboard the vehicle.

In addition to facilitating communication, SOIS provides an electronic data sheet (EDS) standard that enables reuse of devices and software functions among projects and among agencies.  In this role, SOIS can assure compatibility of data interfaces of reused applications in new assemblies.

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