Starlink estimated elsets (Re: Upcoming Florida launch track)

From: Marco Langbroek via Seesat-l <seesat-l_at_satobs.org>
Date: Wed, 6 Nov 2019 14:53:08 +0100
Op 6-11-2019 om 11:41 schreef satcom ops via Seesat-l:
> https://i.postimg.cc/dQh56TXY/florida-launch.jpg
> 
> Falcon 9 rocket . Another 60 sats ?
>

Yes, this will be a new SpaceX Starlink launch of 60 objects.

The elsets below are estimates based on four launch moments on the first of the
two potential launch dates: start of launch window; briefly after start of the
window; halfway the window; and just before the end of the window.

It is under the assumption that lauch will be into a 440 km (initial) orbital
altitude, 53 degree inclined orbit, like the launch in May.

(the azimuth of the hazard zones rather suggests 51.4 degrees, but it probably
will be 53 degrees again).

The possible error in time for passes based on these elsets is in the order of a
few minutes, so allow a generous several minute window for your observations. In
May, the actual pass was 3 minutes early a day after launch, based on a
similarly estimated elset.


STARLINK                               for launch 2019-11-11 14:46 UT
1 70000U 19999A   19315.61527778  .00000000  00000-0  00000-0 0    09
2 70000 053.0000 168.9187 0001467 047.2920 324.9821 15.42070599    00

STARLINK                               for launch 2019-11-11 14:50 UT
1 70001U 19999A   19315.61805556  .00000000  00000-0  00000-0 0    03
2 70001 053.0000 169.9215 0001467 047.2920 324.9821 15.42070599    04

STARLINK                               for launch 2019-11-11 15:20 UT
1 70002U 19999A   19315.63888889  .00000000  00000-0  00000-0 0    06
2 70002 053.0000 177.4420 0001467 047.2920 324.9821 15.42070599    07

STARLINK                               for launch 2019-11-11 15:50 UT
1 70003U 19999A   19315.65972222  .00000000  00000-0  00000-0 0    04
2 70003 053.0000 184.9626 0001467 047.2920 324.9821 15.42070599    09

Western Europe, specifically the southern parts, will have some twilight
sigthing opportunities on the 2nd revolution after launch. The US east- and
westcoast 9 resp 12 hours after launch.

Other opportunities are the next day, but after that visibility quickly
disappears as the passes move into daylight.

The 22 minute shift of the time window for the two launch dates indicated, point
out that a particular orbital plane is aimed for.

A launch at the start of the time window (i.e. near 14:46-14:50 UT) will put the
orbital plane at ~45 degrees distance in RAAN of that of the May 24 launch; a
launch near the end of the time window at ~60 degrees in RAAN. So I guess they
aim for multiples of 5 or 15 degrees.

- Marco


-----
Dr Marco Langbroek  -  SatTrackCam Leiden, the Netherlands.
e-mail: sattrackcam_at_langbroek.org

Station (b)log: http://sattrackcam.blogspot.com
Twitter: _at_Marco_Langbroek
-----
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Received on Wed Nov 06 2019 - 07:54:01 UTC

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