[Css-csts] Re: CSTS services and IOAG service catalog assessements

[Margherita.di.Giulio at esa.int]

Dear Erik,

some preliminary considerations about the items to be discussed with IOAG. 


FORWARD FILE SERVICE 

The IOAG Catolg 1, requests a FORWARD FILE SERVICE providing these two key 
features:

[text from IOAG Catolg 1]
A) This Service enables a mission to send the contents of a file to a 
spacecraft by allowing a Control Center to provide a Ground Tracking Asset 
with files for uplink 
B) It is assumed that a generic transfer file service allowing to transfer 
files between two units, i.e. [CFXS], will be available and - on top of 
this generic service ? more ?specialized? file services will allow 
requesting the dedicated processing for the file being transferred. 

So, the matter is, to produce a service that entails  two parts;
1) first, delivery of files from one ground element to another (that is, 
from MCS to GS for uplinking to the spacecraft). The files will be 
complemented with processing instructions (use CFDP, Space Packets, 
encapsulation Packets)
2) then, the true uplink part, from GS to spacecraft. So, the GS will be 
"managing" the uplink; either via the CFDP Entity (this may or may not 
require COP-1, the uplink in CFDP can be achieved via BD-types of TC) or 
any other means.

In my view, bullet 1 implies that the terrestrial part of FORWARD FILE 
SERVICE is achieved via the upcoming File Transfer concept, that is being 
developed by the BOF ( plus file processing instructions) --> so, no 
specific (or dedicated) cross support service.
Bullet 2 implies closing the uplink loop at the Ground Station, which we 
understand as not being very much beloved by any Agency.
IOAG should explain if this is really a Service that they want.


RETURN FILE SERVICE 

The correct sentence from the MoM of the CSTS WG is only "The exact scope 
needs to be discussed with IOAG"( the rest of the sentence is not 
pertinent to return services).
Looking at IOAG Catolg 1, the RETURN FILE SERVICE entails reconstructing 
the file at the Ground Station ( e.g via a CFDP Entity, or other means), 
and then sending it - plus some reporting information - to the MCS. The 
latter part should be covered by the File Transfer concept .
By the way, in the absence of a suitable RETURN FILE SERVICE, NASA 
implemented a private protocol where the file is, indeed, reconstructed at 
the GS, but the CFDP Entity delivers CFDP control information flowing back 
from the Ground Station to the MCS (and, by the way, ESA 
is studying the same approach). 


We can discuss these themes  further, possibly in a short teleconference, 
and then formulate the questions for the  IOAG .
Kind regards,
Margherita

-------------------------------------------------------------
Margherita di Giulio
Ground Station Back-end Section (HSO-GIB)
European Space Agency ESA/ESOC
Robert-Bosch-Str. 5
D-64293 Darmstadt - Germany
Tel: +49-6151-902779
e-mail: Margherita.di.Giulio at esa.int





From:   "Barkley, Erik J (3970)" <erik.j.barkley at jpl.nasa.gov>
To:     "Margherita.di.Giulio at esa.int" <Margherita.di.Giulio at esa.int>, 
Cc:     "css-csts at mailman.ccsds.org" <css-csts at mailman.ccsds.org>, 
"Nestor.Peccia at esa.int" <Nestor.Peccia at esa.int>
Date:   07/04/2014 13:05
Subject:        CSTS services and IOAG service catalog assessements



Margherita, 
 
At the CMC/CESG meeting today, the following bullet points were presented 
re the IOAG services assessment:
 
 
 

Forward File Service
2020
TBC
The exact scope needs to be discussed with IOAG. Closing the loop in the 
Ground-Stations appears today not to be a desired operational approach 
(COP-1 & CFDP). 
Return File Service
2020
TBC
The exact scope needs to be discussed with IOAG. Closing the loop in the 
Ground-Stations appears today not to be a desired operational approach 
(COP-1 & CFDP). 
Return Unframed Telemetry Service
2020
Yes
There is an ANSI standard (ANSI/AIAA S-124-2007) that refines the RAF SLE 
service. As an ANSI standard exist, IOAG should confirm the needs for a 
CSTS Service.
 
With regard to forward and return file service I believe we will need to 
develop a precise of questions to pose to IOAG.   So we have an action 
item here. 
Also, there was a comment from the DLR CMC representative that COP-1 is 
closed at the ground station. 
 
With regard to RUFT, I think we what will need to do is have a relatively 
precise statement of the ANSI standard functionality to help support any 
decision/analysis with a regard to a CSTS based RUFT vs SLE based RUFT. 
 
Best regards,
 
-Erik

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