Re: Discrepancy

From: Jonathan McDowell via Seesat-l <seesat-l_at_satobs.org>
Date: Sun, 4 Jul 2021 11:11:20 -0400
I concur.  I am assuming at the moment that the SpaceTrack numbering is a
mistake and will be corrected - but I could be wrong.
It will be at least Tuesday before we know more, and possibly longer as it
will take them a while to catalog the Transporter-2 objects
and the cubesat deployments from Cygnus NG-15.
 - Jonathan

On Sun, 4 Jul 2021 at 06:18, 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 that has been given an unpublished catalogue number but without any orbital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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Received on Sun Jul 04 2021 - 10:12:37 UTC

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