[Sea-sa] [EXTERNAL] potential SOIS application support functions

Tue May 26 20:47:40 UTC 2020

Hi Guys,

Just to help clarify the context change in the ASL doc.  What we have done is to shift the entire document from talking about "the SOIS Area does this" and "the MOIMS Area does that" to a discussion that is cats in terms of "Spacecraft Onboard functions" and "Mission Operations functions". A part of this must acknowledge that while SO function only operate on-board, and likely in a real time, time and resource constrained environment, that it is possible for to MO functions, like mission or observation planning, or navigation route calculations, that normally execute on the ground, to be migrated on-board.  There are lots of ways to do this, including developing new code, re-writing code for the on-board, resource constrained, environment, or running ported code in a co-processor if such a resource is available.   This is all part of the whole "3 case" discussion, which remains, but in this same sort of edited format.  This is the new intro text related to this in sec 1.3:

"As in most CCSDS technical documents, in this document these standards will be described based on their functional groupings and deployment locations and will not referenced by the Areas or Working groups that develop and maintain them.  They are described as Mission Operations (MO) services and standards and Spacecraft Onboard (SO) services and standards."

The last thing to say is the text that we introduced to describe the difference between [Future] and [Prospective].   This is the new intro text related to this subject in sec 1.3:

"The policy for CCSDS documents is that they are to be reviewed, and updated as needed, nominally every five years.  This document, because of its design that touches on many other standards, is likely to become out of date during that time.  The reader is cautioned that this may be the case and it is strongly recommended that the CCSDS Publications website be consulted for the latest versions of any standards identified herein.  This will particularly be the case for any standards that are marked [Future] or [Prospective].

In cases where there is no existing CCSDS Recommended Standard, but one is in process or in the plan for future CCSDS standardization it will be marked [Future].  If there is a described concept for a standard, but no concrete plan to produce it, it will be marked as [Prospective].  There is no guarantee that [Prospective] standards will be produced nor that they will look like what is described herein."

As Ramon indicated, we want to enlist your help in arriving at a descriptive set of "implementation neutral" SO function names that reflect what you plan to do [Future] or that you think you may do or would like to do [Prospective].

Thanks, Peter

From: SEA-SA <sea-sa-bounces at mailman.ccsds.org> on behalf of Ramon Krosley <r.krosley at andropogon.org>
Date: Friday, May 22, 2020 at 5:18 PM
To: "Wilmot, Jonathan J. (GSFC-5820)" <jonathan.j.wilmot at nasa.gov>, "'Hickey, Joseph P. (GSFC-582.0)[VANTAGE SYSTEMS INC]'" <joseph.p.hickey at nasa.gov>, "'Prochazka, Marek (JSC-OA111)[EUROPEAN SPACE AGENCY]'" <marek.prochazka at esa.int>, 'Richard Melvin' <Richard.Melvin at scisys.co.uk>, "'Rakow, Glenn P. (GSFC-5610)'" <glenn.p.rakow at nasa.gov>, 'Xionwen He' <hexw501 at hotmail.com>, SEA-SA <sea-sa at mailman.ccsds.org>
Subject: [EXTERNAL] [Sea-sa] potential SOIS application support functions

This message is to obtain a set of potential SOIS application support
functions in the ASL-ADD Green Book.  The names should be reasonably
generic, so anyone with experience in the area would be likely to recognize
what they do.
The following list includes the silvered magenta book functions, plus the
list that was given me during the 2019 Spring meeting in Mountain View, plus
Marek's comments.  One of the names was changed from "Memory Dwell" to
"Diagnostic Telemetry" as a suggestion from the SEA System Engineering
Working Group.
The text here is copied from the ASL-ADD Green Book in its current state of
revision in response to CESG review.  One of the results of that revision is
that "SOIS", which is an organizational area in CCSDS, is not used; instead,
the term "SO" (Spacecraft Onboard) is used to refer to an area of
engineering interest.  Another result of the revision is to define the
[Future] category to represent definite plans of CCSDS working groups, and
to define the [Prospective] category to represent potential work that is not
yet planned and may never be planned.
--------
These are the silvered application support functions.
-               Command and Data Acquisition Services: This has been revived, and it
is the current scope of SEDS.
--             Device Data Pooling Service [Future] has been implemented, and so is
a good candidate for publication as an example application support service
SEDS instance.
-               Time Access Service [Prospective]: This service will provide an
interface for setting and indicating time-correlated events for
synchronizing applications.  Time synchronization is expected to be
accessible for most clock devices through command and data acquisition
services derived from SEDS.
-               File and Packet Store Services [Prospective]: These services will
provide an interface required by MO functions.
-               message transfer service: The name of this function is all lowercase
because it represents a generic concept that has multiple possible
implementations.  A simple function that routes space packets, using the
Application Process Identifier (APID) to designate a logical data path, is
an example implementation.  This function has been described as a subset of
AMS.  The subset of AMS for this function will be described by SEDS
[Prospective], but an accompanying Recommended Practice will be unnecessary
because of the existence of AMS books.
-               Device Enumeration Service [Prospective]: This service will provide
an onboard searchable database of devices managed by SO.  The subnetwork
Device Discovery Service populates the database.

This is the list of [Prospective] Application Support Services from the 2019
Spring meeting.
-               CCSDS File Distribution Protocol transfers files between vehicle and
ground.
-               Checksum functions checks data integrity of memory, data, and files.
-               Data Storage records housekeeping, engineering, and science data for
later download.
-               File Manager provides interfaces to the ground for managing files
onboard.
-               Housekeeping collects and packages telemetry from onboard
applications.
-               Health and Safety ensures that critical tasks check in, services
watchdog, detects CPU hogging, and calculates CPU utilization.  Management
of platform resources by SO applies to the processor(s) in which real-time
activities occur.
-               Limit Checker monitors values and takes action when they cross
thresholds.
-               Diagnostic Telemetry allows ground to telemeter the contents of
memory locations, generally for debugging.
-               Memory Manager loads and dumps memory, on request.
-               Scheduler schedules onboard activities, such as housekeeping
requests.
-               Stored Command executes sequences of commands at absolute or
relative times.

The following list was provided by Marek Prochazka in a comment on the
ASL-ADD Green Book.
--             Event-Action Service allows to trigger onboard action based on an
event generated onboard.
--             OBCP allows to execute small script-like command sequences with flow
control logic.  I think this acronym is for On Board Command Processor.
This function is perhaps close enough to the Stored Command function above
that we should consider them to be the same function for the purpose of this
list.  Unless someone comments otherwise, I'll keep this function, and
remove the Stored Command function above.
--             Critical Event Log allows generation and retrieval of critical
onboard events.
--------
When and if SOIS commits any of these functions to publication, their names
can change again at that time.  If you have any changes to the list above,
then please send me an email before the end of your local-time business day
on 2020 May 29.  Thanks!
Ramon

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