1. The owner of the satellite generally publishes the pre-launch TLEs, which are only estimates.

2. NORAD identifies the object and assigns an object number. Sometimes, with multiple satellites on the same launch, it can take days or weeks to determine which object is which. But the object number, once assigned, remains unchanged.

3. AMSAT -- specifically, the AMSAT VP-Operations, assigns OSCAR numbers when requested to do so by the owner of the satellite. Not every owner makes this request (hence, RS-44 or LILACSAT-2, etc.).

4. Not every agency outside of amateur radio circles recognizes OSCAR numbers, and so they use the pre-launch name or something else. Keplerian elements released by AMSAT always do go by the OSCAR number, but CeleTrak and others may not.

Actually, the names don't mean much. You can call a satellite anything you want. The real identifier is the NORAD object number. That's the only part of the TLE that is consistent.

Mark D. Johns, KØJM
AMSAT Ambassador & News Service Editor
Brooklyn Park, MN USA EN35hd

-----------------------------------------------

"Heaven goes by favor; if it went by merit,

you would stay out and your dog would go in."

---Mark Twain

On Fri, Dec 13, 2024 at 2:47 PM David Spoelstra via AMSAT-BB <amsat-bb@amsat.org> wrote:

I’m trying to understand the process of naming satellites and putting their TLEs in the official sources.

It seems like Space-Track is the official source of TLEs. Is that correct? It seems like CelesTrak and AMSAT are secondary sources. Is that correct?

It seems like the process is this:
When a satellite is first launched, various people associated with it post preliminary TLEs with a temporary ID number.
At some point an official ID number is generated. Who does this? I’m assuming NORAD?
At some point, the satellite is given a name like “AO-123” versus “2024-199AY” or “OBJECT AY”. Who does this? Is that an “official” name that all TLEs should use?
At some point it seems like the TLE sources align with the same name. Who drives that?

For example, let’s take AO-123. AMSAT lists it as:
AO-123
1 61781U 24199AY 24347.80600981 .00010127 00000-0 42052-3 0 9997
2 61781 97.3799 212.0032 0019112 106.8236 253.5099 15.23855779 49614

Space-Track lists it as:
0 OBJECT AY
1 61781U 24199AY 24348.46265841 .00010225 00000-0 42439-3 0 9990
2 61781 97.3798 212.6494 0019118 104.7477 255.5880 15.23869705 49716

CelesTrak lists it as:
2024-199AY
1 61781U 24199AY 24348.46265841 .00010225 00000+0 42439-3 0 9999
2 61781 97.3798 212.6494 0019118 104.7477 255.5880 15.23869705 49716

When will Space-Track and CelesTrak list it as AO-123? Who decides that?

Also, why is AMSAT’s TLEs so far behind Space-Track and CelesTrak? Notice AMSAT lists revolution 49614 versus the others that list revolution 49716 so it’s quite a bit behind.

Lastly, sometimes the TLE sources never seem to align on a name. A good example of this is AO-91. AMSAT lists it as:
AO-91
1 43017U 17073E 24347.62953177 .00010752 00000-0 59525-3 0 9997
2 43017 97.5481 217.2046 0193324 54.2789 307.6249 14.99383406382348

However, CelesTrak lists it as:
RADFXSAT (FOX-1B)
1 43017U 17073E 24347.89647055 .00011020 00000+0 60999-3 0 9996
2 43017 97.5480 217.4635 0193277 53.3813 308.5014 14.99389431382386

Why don’t they use the same name after all these years? Who decides that?

Thanks for helping me to understand the intricacies of this process.

-David, N9KT

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Sent via AMSAT-BB(a)amsat.org. AMSAT-NA makes this open forum available
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