Decay watch update

Alan Pickup (alan@wingar.demon.co.uk)
Sat, 17 Jan 1998 22:03:04 +0000

The latest elset for the decaying Long March rocket is
Iridm CZ-2C r   10.0  3.0  0.0  3.0 d            276 x 154 km
1 25079U 97077C   98017.75197111  .02488172 -12859-5  33129-3 0  1132
2 25079  86.2731 100.1118 0092867   7.9236 352.3518 16.21648597  6364

This shows it 10 seconds early against yesterday's "9107" SatEvo orbit
evolution. My prediction for its decay now stands at January 20.4 +-0.4
day.  Predicted elsets from my "9113" evolution:
Iridm CZ-2C r   10.0  3.0  0.0  3.0 d            268 x 153 km
1 25079U 97077C   98018.06034225  .02786825  21442-2  33594-3 0 91138
2 25079  86.2725  99.9338 0087202   6.5836 353.5304 16.23323884  6417
Iridm CZ-2C r   10.0  3.0  0.0  3.0 d            254 x 152 km
1 25079U 97077C   98018.55308435  .03182462  39182-2  32178-3 0 91134
2 25079  86.2714  99.6484 0077294   4.4356 355.6326 16.26243387  6495
Iridm CZ-2C r   10.0  3.0  0.0  3.0 d            237 x 150 km
1 25079U 97077C   98019.04487114  .03939500  67922-2  31515-3 0 91131
2 25079  86.2702  99.3623 0065937   2.2820 357.7479 16.29711765  6571

I note that NASA GSFC's latest 60 day decay forecast (issued on the 15th
and "effective" on the 14th) has this decaying as early as the 15th. 


As a postscript, one further and (I assume) final elset did indeed
appear for the NEAR Delta 2 decayer:
NEAR r           5.4  2.9  0.0  5.5 d            191 x 120 km
1 23785U 96008B   98017.59347618  .13165387  00000-0  13130-3 0  5302
2 23785  25.8883 112.8584 0055033  43.7364 316.8037 16.43903629 78470
Both the drag and mean motion terms appear too low, but the implied
equator crossing is but 2.1 seconds late on my final prediction. My
estimate of re-entry near the following northbound crossing at 15:41 UTC
still stands. The current 60-day forecast was for decay on the 16th.


Oh, and yes, apologies for titling the posting of today's SatEvo decay
list #46 as "#26" instead. Just seeing how many of you are awake... ;-)

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/