Decay watch update: early January 9

Alan Pickup (alan@wingar.demon.co.uk)
Sat, 9 Jan 1999 01:19:39 +0000

In the hope of refining my prediction for the decay of #21148, the
Lacrosse 2 rocket (which briefly became "Lacrosse 3 rocket" in my
previous message) I've been awaiting further elsets from OIG. One
further elset did appear, for epoch 99008.78174788, showing it running
2.4 seconds late on my earlier prediction for that orbit; this was six
hours ago and no more elsets have materialised since.

SpaceCom did, however, issue the following decay notice:

Object                            Notice issued    Predicted decay
                                       UTC              UTC
     
#21148 = Lacrosse 2 r             Jan  8 21:38     Jan  9 03:54 +-5h

They intend to issue their next report two hours before decay.

Incorporating the latest elset, I think there is a good chance of the
rocket surviving beyond my earlier decay time of 03:30 UTC, with decay
more likely on the approach to following southbound crossing near 73 deg
W at 04:13. This improves the prospects for decay during the SE-bound
pass across the E USA. The uncertainty, however, is still a couple of
hours either way. A new prediction for the final revs:

Lacrosse 2 r     9.8  3.0  0.0  5.0              145 x 139 km
1 21148U 91017B   99009.02488788  .20306975  37170+0  28263-3 0 91079
2 21148  67.9431 279.2868 0004067 117.9072 242.1340 16.48997115 64955
Lacrosse 2 r     9.8  3.0  0.0  5.0              136 x 132 km
1 21148U 91017B   99009.08549168  .31062752  99289+0  26647-3 0 91072
2 21148  67.9422 279.0765 0003083 117.8247 242.2066 16.52003174 64964
Lacrosse 2 r     9.8  3.0  0.0  5.0              120 x 118 km
1 21148U 91017B   99009.14594619  .89357870  11302+2  33770-3 0 91078
2 21148  67.9406 278.8655 0001569 117.7419 242.2740 16.57878443 64972

Alan
-- 
 Alan Pickup | COSPAR 2707:   55d53m48.7s N   3d11m51.2s W   156m asl
 Edinburgh   | Home:   alan@wingar.demon.co.uk    +44 (0)131 477 9144
 Scotland    | SatEvo page:     http://www.wingar.demon.co.uk/satevo/