Updated MUOS 5 elements after new manoeuvres

From: Ted Molczan via Seesat-l <seesat-l_at_satobs.org>
Date: Sat, 17 Sep 2016 12:18:41 -0400
Brad Young and Peter Wakelin have reported new observations of MUOS 5, which reveal that it has made significant new
manoeuvres, that raised both perigee and apogee.

MUOS 5 had last been observed on 2016 Sep 01 UTC, by Brad. Mike McCants derived the following elements.

                                                     15754 X 35735 km
1 41622U 16041A   16244.90028219  .00000000  00000-0  00000-0 0    08
2 41622   9.7417 322.1118 3110922 183.7964 173.1852  1.50856792    09

I derived the following elements from the new observations.

MUOS 5                                               16102 X 36683 km
1 41622U 16041A   16261.00478009  .00000000  00000-0  00000-0 0    04
2 41622   9.7294 321.4378 3140167 184.9917 186.9725  1.46376083    03
Arc 20160916.89-09170 WRMS resid 0.001 totl 0.001 xtrk

Although the residuals are small, the arc is fairly short; therefore, these results should be considered approximate. If
it can be observed again before it manoeuvres, then that should result in more reliable elements.

A conjunction analysis between the two orbits yields closest approach on Sep 11 near 07:00 UTC, but since the perigee
and apogee both changed, that is likely the approximate mid-point between multiple manoeuvres. Their total delta-V is
approximately 24 m/s, which exceeds the ~20 m/s of the series of small manoeuvres that occurred over a several week
period during July-August. Since the new manoeuvres appear to have occurred over a shorter period, they probably were
fewer in number and larger in magnitude. This may be an indication of the start of a new phase in the effort to achieve
a usable orbit.

Ted Molczan


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Received on Sat Sep 17 2016 - 11:19:25 UTC

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