[SLS-CC] [EXTERNAL] RE: Updated Proximity-1 Directives and Default Session Control Parameters for Lunar Operations

Thu Nov 16 20:57:36 UTC 2023

Hi Gabriele,

Nice to meet you, even if it is only via email.
I included the entire SLP WG on this distribution, since the topic is an important one.
The Prox-1 physical layer standard (CCSDS 211.1-B-4) specifies Channel 1 as the hailing channel for UHF at Mars in which Ch 1 is defined as 435.6 MHz forward and 404.4 MHz return.
I realize that the Mars Program deviated from this standard and utilized Channel 0 as their Hailing Channel and their working channel.
So this difference is a de-facto vs de-jure issue.

CCSDS 211.1-B-4 also says in a NOTE (which is non-normative) that “Enterprise-specific hailing channel frequencies can be defined in the default configuration of the Physical Layer parameters”. Furthermore, in another follow on NOTE (non-normative) in the same section, it says, “if transceivers are compatibly configured, hailing can occur on an agreed-to channel. The first generation transceivers are fixed frequency and use Channel 0”.

So, I believe the Mars Program backward compatibility issue has been documented in 211.1-B-4. Would you agree ?

From an international cross-support CCSDS standard point of view, what I have documented in this proposed Annex for default session control parameters is correct i.e., The Prox-1 standard (CCSDS 211.1-B-4) specifies Channel 1 as the hailing channel for UHF at Mars at those frequencies above. Also per 211.1-B-4, Ch 0 is defined as the forward 437.1 MHz frequency, and the return frequency 401.585625.

Best regards,
Greg
From: DONA' Gabriele <gabriele.dona at thalesaleniaspace.com>
Date: Thursday, November 16, 2023 at 1:35 AM
To: "Kazz, Greg (US 312B)" <greg.j.kazz at jpl.nasa.gov>
Cc: "Brice.Dellandrea at esa.int" <Brice.Dellandrea at esa.int>
Subject: [EXTERNAL] RE: Updated Proximity-1 Directives and Default Session Control Parameters for Lunar Operations

Dear Greg,

I’m not sure whether I should reply to you or to the whole WGs. Anyway here’s my comment about the default parameters used to establish hailing.

In Section A1.1 UHF BAND HAILING CHANNEL PARAMETERS, I believe the default hailing channel should be Channel 0 and not Channel 1. That is important to keep backward compatibility with existing transceivers. By the way, there is a typo:  Ch 0 (404.4 MHz) should read Ch 1 (404.4 MHz) instead. Then, if the intention is to allow hailing on other channels (e.g. channel 1), on specific cases/missions, then I have no objections.

I hope this comments helps.

Regards,
Gabriele.

P.S. In case you wandered, I am the engineering responsible for the UHF subsystems of the ExoMars missions for Thales Alenia Space.

Gabriele Donà, Ph.D.
Thales Specialist
Head of Data Systems & Communication Department

Phone: +39 011 7180 555
Mobile: +39 380 591 6240
Personal Meeting Room: 3080044019
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From: SLS-SLP <sls-slp-bounces at mailman.ccsds.org> On Behalf Of Kazz, Greg (US 312B) via SLS-SLP
Sent: 15 November 2023 23:29
To: Kazz, Greg (US 312B) via SLS-SLP <sls-slp at mailman.ccsds.org>; Space Link Coding & Synchronization Working Group <sls-cc at mailman.ccsds.org>; sls-rfm at mailman.ccsds.org
Cc: Brice Dellandrea <Brice.Dellandrea at esa.int>
Subject: [Sls-slp] Updated Proximity-1 Directives and Default Session Control Parameters for Lunar Operations

Dear CCSDS SLP, C&S, and RFM WGs,

I took the liberty of updating both the Proximity-1 Directive Set as well as the Default Session Control Parameters for Lunar Operations, based upon the inputs provided at the Fall CCSDS Meeting recently concluded in The Hague (Joint meeting held on Nov. 10, 2023).

The update to both the Lunar Proximity directives and the default session parameters is in the CWE now under this SLP WG directory:
https://cwe.ccsds.org/sls/docs/Forms/AllItems.aspx?RootFolder=%2Fsls%2Fdocs%2FSLS%2DSLP%2FMeeting%20Materials%2F2023%2FFall%2FPost%20Meeting%20Prox%201%20work&FolderCTID=0x012000439B56FF51847E41B5728F9730D7B55F&View=%7BAE8FB44C%2DE80A%2D42CF%2D8558%2DFB495ABB675F%7D<https://urldefense.us/v3/__https:/cwe.ccsds.org/sls/docs/Forms/AllItems.aspx?RootFolder=*2Fsls*2Fdocs*2FSLS*2DSLP*2FMeeting*20Materials*2F2023*2FFall*2FPost*20Meeting*20Prox*201*20work&FolderCTID=0x012000439B56FF51847E41B5728F9730D7B55F&View=*7BAE8FB44C*2DE80A*2D42CF*2D8558*2DFB495ABB675F*7D__;JSUlJSUlJSUlJSUlJSUlJSUlJQ!!PvBDto6Hs4WbVuu7!L1wAVo628dCMgtpAAumuBTZAr-X3maH_jE88g_kNyAIz5t8dXwpN9AfIWXmU1LBJ8LslZfBgCPKTxNV-al8m1fXa6YllEl-cRGoUqlwQ$>

There are still several TBDs remaining to be resolved including the action items taken by the RFM WG (e.g., define specific hailing and working channel frequencies at S-band, etc)
I am also interested to know if you have specific values for the new parameter: Mod Index.

Please let me know if you have comments, so that I can incorporate them into these two normative annexes which will reside in the restructured Space Data Link Protocol Session Control Blue Book.

Best regards,
Greg
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