X-37B OTV 4 search elements

From: Ted Molczan via Seesat-l <seesat-l_at_satobs.org>
Date: Sat, 24 Oct 2015 12:48:15 -0400
Greg Roberts performed a planar search for OTV 4 (15025A / 40651) on 2015 Oct 22, from about 17:42 UTC to 18:53 UTC. It
was not seen in the epoch 15224.08279714 orbit. Observation report here:

http://satobs.org/seesat/Oct-2015/0133.html

Alberto Rango made a highly probable sighting overnight, Oct 24 near 03:16 UTC. Observation report here: 

http://satobs.org/seesat/Oct-2015/0141.html

The following search elements fit Alberto's observation and would have passed outside the period of Greg's search.

If it reduced its altitude, then it may be close to one of these orbits or somewhere in-between:

1 77001U          15297.12071445  .00000000  00000-0  00000-0 0    06
2 77001  38.0316  17.2359 0006000 206.7574 153.2909 15.96000000    02

1 77002U          15297.12122311  .00000000  00000-0  00000-0 0    06
2 77002  38.0316  21.6634 0006000 206.7620 153.2861 15.90000000    01

Tonight, it may pass at least several minutes before the 77001 TLE and after the 77002 TLE.

If it increased its altitude, then this may be close:

1 77003U          15297.12178148  .00000000  00000-0  00000-0 0    06
2 77003  38.0316  27.4243 0006000 206.7669 153.2807 15.75000000    08

This orbit passed near end of Greg's search, but may have been outside his FOV.

A mean motion of 15.8 rev/d would not fit, because the required RAAN would have drifted farther east than was possible
based on the change in rate of precession, aggregated over the 73 days since the last observation. Therefore, if it did
raise its altitude, then tonight OTV 4 probably will not pass much earlier than the 77003 orbit.

Ted Molczan


_______________________________________________
Seesat-l mailing list
http://mailman.satobs.org/mailman/listinfo/seesat-l
Received on Sat Oct 24 2015 - 11:49:10 UTC

This archive was generated by hypermail 2.3.0 : Sat Oct 24 2015 - 16:49:10 UTC