Decay of 96- 54 B = Centaur r

Alan Pickup (alan@wingar.demon.co.uk)
Sat, 15 Mar 1997 22:02:47 +0000

Having been away all day, I've only been able to tackle this interesting
object in the past couple of hours.

The latest OIG elsets for this are:
Centaur r                                        5328 x 100 km
1 24316U 96054B   97074.30063786  .00112179 -19108-4  52326-5 0   764
2 24316  25.2175  88.8864 2875202 267.1283  60.2174 10.01432485  8957
Centaur r                                        5113 x 89 km
1 24316U 96054B   97074.40033338  .06214934 -19855-4  17384-3 0   776
2 24316  25.2021  88.8220 2797505 267.4663  60.6065 10.20464813  8962
Centaur r                                        4921 x 98 km
1 24316U 96054B   97074.49817405  .41398097 -20345-4  16972-2 0   803
2 24316  25.2441  88.3375 2713684 268.4328  60.7912 10.36194582  8972
Centaur r                                        4763 x 95 km
1 24316U 96054B   97074.59427556  .89217835 -20851-4  32485-2 0   821
2 24316  25.2404  88.0107 2649911 269.3199  60.7725 10.50377322  8982
Centaur r                                        4567 x 91 km
1 24316U 96054B   97074.68878157  .93592373 -21413-4  26958-2 0   841
2 24316  25.2373  87.7052 2570129 269.7091  61.5176 10.68568484  8991

I've done my best to fit SatEvo evolutions through these and earlier
elsets. As well as varying the start mean motion and ndot/2 terms to get
a decent fit through the equator crossings derived from the published
elsets, I have also adjusted the start eccentricity and mean anomaly to
keep the perigee height reasonable (~96 km) and the initial equator
crossing at the "correct" time.

I've tried two fits:

The first ("9057") evolution is based on an initial elset at 97073.07.
This gives a mean residual of 7 seconds for the "best" 11 elsets since
that time. By "best" I mean that I ignore duplicate elsets by taking
only the last-issued elset on each rev. The worst residual is 20s. The
indicated decay is at March 16.79.

The second ("9075") evolution is based on a more recent start elset at
97074.19. It has a mean residual of 6s and a worst residual of 16s (at
97074.59) over the 6 best elsets in the meantime. The indicated decay is
also at March 16.79.

The following predicted elsets are based on the latter "9075" evolution:

Centaur r                                        4287 x 96 km
1 24316U 96054B   97074.78112098 1.19870882  26472+0  40780-2 0 90752
2 24316  25.1978  87.3264 2445147 269.7730  62.4686 10.94452785  9007
Centaur r                                        4057 x 96 km
1 24316U 96054B   97074.87173013 1.27628928  31034+0  41595-2 0 90752
2 24316  25.1901  86.9914 2342379 270.3457  63.0875 11.16859791  9018
Centaur r                                        3824 x 96 km
1 24316U 96054B   97074.96050803 1.36602040  36982+0  42557-2 0 90756
2 24316  25.1820  86.6507 2235632 270.9283  63.7396 11.40294761  9022
Centaur r                                        3588 x 96 km
1 24316U 96054B   97075.04744537 1.47122456  43950+0  43704-2 0 90758
2 24316  25.1754  86.3038 2124191 271.5215  64.4314 11.64932512  9031
Centaur r                                        3347 x 96 km
1 24316U 96054B   97075.13252487 1.59649519  53627+0  45093-2 0 90758
2 24316  25.1665  85.9501 2007140 272.1263  65.1699 11.90996746  9049
Centaur r                                        3102 x 96 km
1 24316U 96054B   97075.21572079 1.72739012  57608+0  46203-2 0 90759
2 24316  25.1590  85.5893 1884024 272.7434  65.9619 12.18620779  9057
Centaur r                                        2851 x 96 km
1 24316U 96054B   97075.29701079 1.88696806  73248+0  47585-2 0 90753
2 24316  25.1511  85.2206 1754328 273.3741  66.8122 12.47948876  9069
Centaur r                                        2592 x 96 km
1 24316U 96054B   97075.37636466 2.08968729  97109+0  49408-2 0 90756
2 24316  25.1426  84.8433 1616227 274.0195  67.7395 12.79429764  9075
Centaur r                                        2322 x 96 km
1 24316U 96054B   97075.45373227 2.35817499  13664+1  51860-2 0 90755
2 24316  25.1334  84.4565 1467046 274.6814  68.7715 13.13726521  9080
Centaur r                                        2035 x 96 km
1 24316U 96054B   97075.52903443 2.73505003  21075+1  55164-2 0 90755
2 24316  25.1232  84.0587 1302626 275.3620  69.9523 13.51889795  9098
Centaur r                                        1721 x 96 km
1 24316U 96054B   97075.60214633 3.31688700  34958+1  60332-2 0 90758
2 24316  25.1141  83.6481 1115364 276.0647  71.3648 13.95767956  9102
Centaur r                                        1363 x 96 km
1 24316U 96054B   97075.67285905 4.27096725  59768+1  67359-2 0 90753
2 24316  25.1033  83.2216 0891230 276.7947  73.1581 14.48908945  9117
Centaur r                                        923 x 96 km
1 24316U 96054B   97075.74082789 6.45542366  21636+2  80150-2 0 90753
2 24316  25.0893  82.7738 0600541 277.5613  75.6612 15.18845524  9129

Good luck to anyone who tries to spot this.

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    | Royal Observatory: A.Pickup@roe.ac.uk +44 (0)131 668 8224