Re: Discrepancy

From: Bob Christy via Seesat-l <seesat-l_at_satobs.org>
Date: Tue, 6 Jul 2021 21:07:48 +0000
The numbering published through Space-Track was incorrect (Option 1 in my original email).

The Catalogue has been corrected. It now runs:
2021-057 - Soyuz MS-17
2021-058 - LauncherOne
(2021-059 - Transporter 2) - yet to appear
2021-060 - OneWeb cluster
2021-061 - Jilin cluster
2021-062 - Fengyun 3E

2021-063 will be Tianlian 1-05 - launched today.

Robert Christy

> On 4 Jul 2021, at 10:18, Bob Christy via Seesat-l <seesat-l_at_satobs.org> wrote:
> 
> My record of known recent launches (in chronological order) is 
> Jun 29 - Progress MS-17
> Jun 30 - LauncherOne satellite cluster
> Jun 30 - SpaceX Transporter 2 mission
> Jul 1 - OneWeb cluster
> Jul 3 - Jilin cluster
> 
> The first two appear in the SpaceTrack Catalogue under the 2021-057 and 2021-058 designations.
> 
> The SpaceX Transporter satellites are not yet catalogued and no orbital elements have yet been listed to date. It seemed reasonable to assume it will be catalogued as 2021-059 but, based on what follows below, it could be 2021-060
> 
> On July 3, the OneWeb launch was added to the catalogue as 2021-061 and Jilin as 2021-062.
> 
> On the face of it, we are missing 2021-060 or 2021-059.
> 
> Three possibilities arise:
> 1 - an error in the catalogue,
> 2 - a clandestine orbital launch that has gone unannounced, unnoticed by space chroniclers, and not been formally acknowledged through SpaceTrack,
> 3 - a sub-orbital or failed orbital launch has thrown some debris into LEO that has been given an unpublished catalogue number but without any orbital element sets being issued through SpaceTrack.
> 
> Option 1 is possible and is the most likely explanation,
> 
> Option 2 is unlikely, something would surely have leaked through news channels by now.
> 
> Option 3 is possible but then candidates have to be identified unless SpaceTrack or its masters make some announcement.
> 
> In the meantime, as Russell says, it doesn't help with reporting observations but that isn't something I'm qualified to comment on.
> 
> The catalogue is a 'dangerous' place, to use Russell's description. Changes are chronicled by SpaceTrack but details are among the less obvious data on the Space-Track website. Historical research is fraught with such obstacles.
> 
> A recent example is the 2021-014 Yaogan 31 triplet. More than one week after launch, following release of many element sets, objects 'A' and 'B' were switched round. The possible reason is that object 'A' from a launch is not permitted to be a debris item.
> 
> Robert Christy
> 
>> On 4 Jul 2021, at 09:01, Russell Eberst via Seesat-l <seesat-l_at_satobs.org> wrote:
>> There seems to be a dangerous discrepancy evolving over designations.
>> In recent launches, the designations used vary according to which source is accessed.
>> The  OneWeb launch of July 1 (inc = 87°.4) is called 2021-60xx by Jonathan  and Bob,
>> It's called 2021-61xx by spacetrack and celestrak.
>> The next launch, Jilin (inc = 97°.5) is called 2021-61xx by Jon and Bob, and called
>> 2021-62xx by spacetrack and celestrak.
>> This disparity needs to be addressed before many more launches continue this divergence.
>> I would like to know which designations should be used when reporting observations of
>> these and upcoming satellites?
>> best wishes
>> Russell
>> 
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> 
> 
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Received on Tue Jul 06 2021 - 16:09:11 UTC

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