Re: NROL-108 elset estimates

From: Marco Langbroek via Seesat-l <seesat-l_at_satobs.org>
Date: Fri, 18 Dec 2020 13:19:19 +0100
After yesterday's scrub, NROL-108 is now re-slated for 19 Dec 2020. The launch
window runs from 14:00 to 17:00 UT.

Here are two estimated elset variants for the start of the time window, one for
a ~52 degree orbital inclination, the other for a ~50 degree orbital inclination:

NROL-108  52 deg                for launch at 2020 Dec 19 14:00:00 UT
1 70000U 20999A   20354.58333333  .00000000  00000-0  00000-0 0    04
2 70000 051.9500 194.5181 0003690 047.9580 324.6522 15.56602223    05

NROL-108  50 deg                for launch at 2020 Dec 19 14:00:00 UT
1 70001U 20999A   20354.58333333  .00000000  00000-0  00000-0 0    05
2 70001 050.0000 192.5775 0003690 049.1295 324.6522 15.56602223    05


The same elsets, but re-epoched for launch at the end of the time window:

NROL-108  52 deg                for launch at 2020 Dec 19 17:00:00 UT
1 70003U 20999A   20354.70833333  .00000000  00000-0  00000-0 0    06
2 70003 051.9500 239.6413 0003690 047.9580 324.6522 15.56602223    07

NROL-108  50 deg                for launch at 2020 Dec 19 17:00:00 UT
1 70004U 20999A   20354.70833333  .00000000  00000-0  00000-0 0    07
2 70004 050.0000 237.7007 0003690 049.1295 324.6522 15.56602223    08


The orbital plane of USA 276 passes over the launch site at 16:13 UT on 19
December. If (speculation!) NROL-108 targets that plane, launch will be around
16:05 UT:


NROL-108  52 deg                for launch at 2020 Dec 19 16:05:00 UT
1 70005U 20999A   20354.67013889  .00000000  00000-0  00000-0 0    00
2 70005 051.9500 225.8537 0003690 047.9580 324.6522 15.56602223    03

NROL-108  50 deg                for launch at 2020 Dec 19 16:05:00 UT
1 70006U 20999A   20354.67013889  .00000000  00000-0  00000-0 0    01
2 70006 050.0000 223.9131 0003690 049.1295 324.6522 15.56602223    05


For backgrounds to NROL-108, see my initial post here:
http://www.satobs.org/seesat/Dec-2020/0073.html

Elsets can be easily re-epoched to match the eventual actual launch time using
my 'TLEfromProxy' software: http://software.langbroek.org

- Marco


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

Cospar 4353 (Leiden):     52.15412 N, 4.49081 E (WGS84), +0 m ASL
Cospar 4355 (Cronesteyn): 52.13878 N, 4.49937 E (WGS84), -2 m ASL
Station (b)log: http://sattrackcam.blogspot.com
Twitter: _at_Marco_Langbroek
-----
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Received on Fri Dec 18 2020 - 06:20:00 UTC

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