Re: TLE for GPS III SV03 (Columbus)

From: Richard Cole via Seesat-l <seesat-l_at_satobs.org>
Date: Tue, 30 Jun 2020 15:09:56 +0000
There is an article on Spaceflightnow.com that says:

> Mission planners also changed the perigee of the spacecraft’s initial orbit after launch from around 740 miles [for SV01] to 250 miles [for SV03], according to Col. Edward Byrne, senior materiel leader at SMC’s Medium Earth Orbit space systems division.

Elsewhere it is clear this is the transfer orbit that is being referred 
to. Therefore, the initial injection orbit has a much lower apogee than 
on SV01 (which have have put it at 1300km altitude at the second stage 
reignition at T+62mins). This will make it lower and much brighter on 
the first orbit pass over Europe.

regards

Richard Cole


On 28/06/2020 08:31, C. Bassa via Seesat-l wrote:
> During the GPS III SV01 launch, also on a Falcon 9, I tracked the GPS
> S-band beacon during the first pass over Europe and determined a rough
> TLE from that. See
> https://twitter.com/cgbassa/status/1076850608227926016?s=20
> 
> Propagating that TLE to the 2020-06-30T19:55:00 launch time at window
> open gives this estimate:
> 1 75001U 20999A   20182.83560185  .00000000  00000-0  50000-4 0    03
> 2 75001  55.0000 115.1011 0789184  53.6145 357.4290 14.39464904    00
> 
> This TLE assumes that GPS III SV03 will follow a similar launch
> trajectory as GPS III SV01, which is not clear to me at this point.
> For SV01, SpaceX used two burns on the upper stage, first into a coast
> orbit, then into the insertion orbit. This TLE is valid for the coast
> orbit. When/if data becomes available on the de-orbit area of the
> upper stage we can check if a similar launch profile is used for SV03.
> 
> Regards,
>      Cees
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Received on Tue Jun 30 2020 - 10:11:04 UTC

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