Decay watch: January 27

Alan Pickup (alan@wingar.demon.co.uk)
Wed, 27 Jan 1999 15:54:07 +0000

SpaceCom have released the following decay notices since my posting
yesterday:

Object                            Notice issued    Predicted decay
                                       UTC              UTC

#25065 = ETS-7 H2 r               Jan 26 20:00     Jan 27 18:59 +-17h
#25065 = ETS-7 H2 r               Jan 27 07:36     Jan 27 19:03 +-7h
#25065 = ETS-7 H2 r               Jan 27 12:49     Jan 27 18:55 +-4h

#25617 = ROCSAT-1 Orb Adjust Mod  Jan 27 05:31     Jan 29 18:56 +-2d

               -------------------------------

The latest elset for the ETS-7 H2 rocket ...

ETS-7 H2 r      13.5  2.5  0.0  3.0 v            171 x 162 km
1 25065U 97074C   99027.52153601  .12109839  86019-6  86755-3 0  4470
2 25065  34.5175 101.4249 0006860 343.6193  16.4315 16.39717890 66277

... shows it running only 1.5 seconds early against the prediction I
posted yesterday. A new analysis brings the decay forward to January
27.78 (18:48 UTC +-2 hours). This would imply re-entry over the NW
Pacific Ocean near 31 deg N, 170 deg E. The track continues to the S of
Hawaii (18:56) and onwards across Chile and Argentina, as per
yesterday's message. It could still survive to reach Africa.

My prediction for the final orbits runs:
ETS-7 H2 r      13.5  2.5  0.0  3.0 v            165 x 157 km
1 25065U 97074C   99027.58236430  .18522496  24181+0  10364-2 0 94478
2 25065  34.5171 100.9678 0006016 344.2835  15.6978 16.41673175 66283
ETS-7 H2 r      13.5  2.5  0.0  3.0 v            158 x 151 km
1 25065U 97074C   99027.64312043  .24334887  45660+0  91761-3 0 94478
2 25065  34.5166 100.5098 0005034 344.9490  15.0359 16.44240351 66299
ETS-7 H2 r      13.5  2.5  0.0  3.0 v            148 x 143 km
1 25065U 97074C   99027.70376490  .37324988  12458+1  64695-3 0 94472
2 25065  34.5158 100.0507 0003808 345.6162  14.3729 16.47850784 66306
ETS-7 H2 r      13.5  2.5  0.0  3.0 v            128 x 125 km
1 25065U 97074C   99027.76422986 1.09486476  16617+2  55707-3 0 94477
2 25065  34.5145  99.5897 0001915 346.2861  13.7086 16.54962846 66317

               -------------------------------

Current elsets for the two objects from the launch of ROCSAT-1 are:

ROCSAT-1                                         602 x 589 km
1 25616U 99002A   99027.47001419  .00181973  00000-0  17630-1 0    58
2 25616  34.9848 282.3348 0009123 173.9145 186.1550 14.90901666    67
ROCSAT-1 OrbAdjMod                               555 x 133 km
1 25617U 99002B   99027.57642451  .09032928  15585-6  53824-3 0    70
2 25617  34.6905 281.0123 0313326 209.4838 148.7818 15.75297909    88

The latter object, the final (3rd) stage of the Athena 1 rocket, will
decay at January 29.74 +-0.5d according to my calculations.

Predicted elsets:
ROCSAT-1 OrbAdjMod                               536 x 134 km
1 25617U 99002B   99027.76632654  .09154818  87185-2  53948-3 0 90075
2 25617  34.6897 279.7117 0299443 211.3665 146.8127 15.78589708   118
ROCSAT-1 OrbAdjMod                               508 x 134 km
1 25617U 99002B   99028.01889526  .09858000  10180-1  55975-3 0 90072
2 25617  34.6886 277.9717 0279798 213.8851 144.2957 15.83387516   153
ROCSAT-1 OrbAdjMod                               479 x 134 km
1 25617U 99002B   99028.27067464  .10723671  12961-1  58325-3 0 90077
2 25617  34.6875 276.2248 0258637 216.4139 141.7989 15.88560730   196
ROCSAT-1 OrbAdjMod                               448 x 133 km
1 25617U 99002B   99028.52160354  .11848785  17297-1  61190-3 0 90073
2 25617  34.6862 274.4703 0235565 218.9538 139.3256 15.94211184   231
ROCSAT-1 OrbAdjMod                               413 x 133 km
1 25617U 99002B   99028.77160220  .13398774  24756-1  64544-3 0 90076
2 25617  34.6848 272.7074 0210052 221.5059 136.8800 16.00499888   277
ROCSAT-1 OrbAdjMod                               373 x 133 km
1 25617U 99002B   99029.02055984  .15806863  40052-1  68701-3 0 90076
2 25617  34.6832 270.9349 0181110 224.0720 134.4701 16.07721112   314


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
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