Decay watch update: January 9

Alan Pickup (alan@wingar.demon.co.uk)
Sat, 9 Jan 1999 17:32:28 +0000

The recent SpaceCom decay notices are:

Object                            Notice issued    Predicted decay
                                       UTC              UTC
     
#21148 = Lacrosse 2 r             Jan  8 21:38     Jan  9 03:54 +-5h
#21148 = Lacrosse 2 r             Jan  9 02:06     Jan  9 03:40 +-2h
#21148 = Lacrosse 2 r             Jan  9 03:25     Jan  9 03:40 +-2h

#25533 = Sputnik 41               Jan  9 07:45     Jan 11 06:48 +-2d

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

The final elset for #21148, the Lacrosse 2 Titan 4 rocket is:

Lacrosse 2 r     9.8  3.0  0.0  5.0              141 x 136 km
1 21148U 91017B   99009.02478336  .16987426  56974-5  19263-3 0  1089
2 21148  67.9361 279.2828 0004042 323.6149  36.4794 16.50208634 64958

This shows it running 11 seconds early on my prediction posted to SeeSat 
at 01:19 UTC (and based on a fit including the preceding elset at 
99008.78). The discrepancy implies that the final decay was more rapid 
than I (or SpaceCom?) expected, though it is a pity that elsets were 
so infrequent near the end - only two being issued during its final 
twelve hours. I now place decay near the southbound equator crossing 
at 02:46 UTC at longitude 51 deg W, near the mouth of the Amazon in 
Brazil. My estimated uncertainty is still at least one hour.

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

...and then there was one :)

My current prediction for Sputnik 41 is for decay on January 11 
at 02:55 UTC +-8h. This object, rather small and faint, leaves eclipse 
near 41 deg N at ~06h local time. It enters the earth's shadow near 
20 deg S at #19h local time.

Predicted elsets:
Sputnik 41       0.2  0.0  0.0  9.5 v            206 x 200 km
1 25533U 98062C   99010.05437938  .04532823  12092-1  13705-2 0 91206
2 25533  51.6481  67.0066 0004806  17.6058 342.4108 16.26093171  9473
Sputnik 41       0.2  0.0  0.0  9.5 v            190 x 185 km
1 25533U 98062C   99010.54522342  .07640329  37514-1  13637-2 0 91208
2 25533  51.6464  64.2772 0003550  19.6405 340.3732 16.31783799  9557
Sputnik 41       0.2  0.0  0.0  9.5 v            152 x 150 km
1 25533U 98062C   99011.03353646  .32397716  86934+0  89478-3 0 91204
2 25533  51.6424  61.5288 0001472  21.6896 338.3166 16.45681227  9638


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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