GSSAP pre-launch elements for 2016 Aug 19 UTC

From: Ted Molczan via Seesat-l <seesat-l_at_satobs.org>
Date: Fri, 19 Aug 2016 01:18:00 -0400
Two Geosynchronous Space Situational Awareness Program (GSSAP) satellites were launched from CCAFS on a Delta 4 Medium+
4,2 rocket, on 2016 Aug 19, at 04:52 UTC - 5 minutes later than originally scheduled.

http://spaceflightnow.com/2016/08/17/d375_journal/

Observers in parts of the western hemisphere may be able to observe the Delta 4 second stage's fuel dump in GEO. This
depends on the GTO burn occurring at the first ascending node, as it did on the first GSSAP launch. If it occurs at the
first descending node, then the fuel dump will be an eastern hemisphere show.

The following elements are based on launch at the above time.

LEO coast                                                258 X 272 km
1 73701U 73701A   16232.22025468  .00000000  00000-0  00000-0 0    02
2 73701  27.2800 218.9704 0010000 183.0000 359.3500 16.05000000    00

If the GTO burn occurs at the first ascending node, then the following TLEs apply:

GTO burn at 1st ascending node                         278 X 36398 km
1 73703U 73703A   16232.25094173  .00000000  00000-0  00000-0 0    08
2 73703  27.2800 218.7304 7307000   3.4000 359.6000  2.23480000    02

Delta 4 2nd stage in final orbit                     36134 X 36215 km
1 73704U 73704A   16232.49236112  .00000000  00000-0  00000-0 0    07
2 73704   0.4851  49.1111 0009503   3.2888 358.9484  0.98907630    07

The 73703 GTO TLE is fairly rough, but may be sufficient to spot the stack as it approaches GEO altitude.

The 73704 TLE is derived from Mike McCants' TLE of the Delta 4 2nd stage of the first GSSAP launch, which was based on
observations. If the mission is a carbon-copy, then this will be highly accurate for spotting the fuel dump, which would
occur near the epoch of the 73704 TLE: 2016 Aug 19 at 11:49 UTC, near 94 W. Mike McCants and Ed Cannon observed the fuel
dump of the first GSSAP at the same mission elapsed time, 6h57m.

If the GTO burn occurs at the first descending node, then the following approximate TLE applies:

GTO burn at 1st descending node                        278 X 36398 km
1 73702U 73702A   16232.22052079  .00000000  00000-0  00000-0 0    02
2 73702  27.2794 218.9649 7307042 182.7762   0.0513  2.23480002    07

The stack would arrive at GEO altitude at about 10:39 UTC near 93 E. The circularization burn would occur soon after,
followed by the Delta 4 second stage fuel dump perhaps 20 min. later.

Ted Molczan


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Received on Fri Aug 19 2016 - 00:19:06 UTC

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