Re: Decay of Mars Pathfinder rocket

Alan Pickup (alan@wingar.demon.co.uk)
Thu, 27 Nov 1997 21:06:31 +0000

Excluding one superseded elset, todays offerings (so far) from OIG are:
Mars Pthfndr r   5.9  2.4  0.0  5.6 d            340 x 141 km
1 24668U 96068B   97331.09776261  .06345767  23716-5  44252-3 0  7491
2 24668  36.3123  79.7308 0150359 222.4970 136.3861 16.12213518 47895
Mars Pthfndr r   5.9  2.4  0.0  5.6 d            324 x 141 km
1 24668U 96068B   97331.40709275  .05248544  24652-5  33473-3 0  7506
2 24668  36.3200  77.5388 0138715 225.7954 133.0944 16.15293474 47949
Mars Pthfndr r   5.9  2.4  0.0  5.6 d            314 x 139 km
1 24668U 96068B   97331.59238022  .05282561  24782-5  29710-3 0  7525
2 24668  36.3123  76.2233 0132529 227.2029 131.7430 16.17321897 47976
Mars Pthfndr r   5.9  2.4  0.0  5.6 d            308 x 138 km
1 24668U 96068B   97331.71578029  .05327643  24883-5  27273-3 0  7539
2 24668  36.3086  75.3321 0128608 228.4750 130.5271 16.18687166 47996

These show it running 9, 30, 51 and 71 seconds late against my SatEvo
evolution of yesterday. Clearly the drag has not increased by anything
like as much as I expected, perhaps because the atmosphere is still
settling down after intense geomagnetic conditions on Sunday - isn't
hindsight wonderful :-)

My latest prediction is for decay at about November 29.0 (+/-0.2d, but
you won't need reminding that my previous prediction was for Nov 28.5
+/-0.3d).

SatEvo predicted elsets for the next few hours, by which time I hope to
post an update:
Mars Pthfndr r   5.9  2.4  0.0  5.6 d            299 x 137 km
1 24668U 96068B   97331.83902917  .06660862  10000-1  30576-3 0 97534
2 24668  36.3083  74.4527 0122524 229.7009 129.2218 16.20597058 48016
Mars Pthfndr r   5.9  2.4  0.0  5.6 d            285 x 137 km
1 24668U 96068B   97332.02369624  .07303487  13432-1  30947-3 0 97530
2 24668  36.3077  73.1312 0112797 231.5433 127.4392 16.23169826 48047
Mars Pthfndr r   5.9  2.4  0.0  5.6 d            265 x 136 km
1 24668U 96068B   97332.26943788  .08552863  18176-1  31594-3 0 97539
2 24668  36.3068  71.3647 0098372 234.0061 125.0778 16.27046549 48081
Mars Pthfndr r   5.9  2.4  0.0  5.6 d            242 x 135 km
1 24668U 96068B   97332.51454994  .10058053  22685-1  31136-3 0 97530
2 24668  36.3058  69.5921 0081479 236.4775 122.7414 16.31594280 48123

With perigee on its southbound leg to the south of the equator, I think
decay is most likely between the southbound equator crossing and the
following northbound one.

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