HST dance w/Cosmos 1300

ROB MATSON (ROBERT.D.MATSON@cpmx.saic.com)
16 Jun 1997 14:27:18 -0800

Hi All,

Has anyone else noticed the "dance" going on between the Hubble Space
Telescope and Cosmos 1300 (Norad #12785)?  I calculate that these two came
within 1.2 km of each other on Saturday, June 14th at 14:43:46.1 UTC, and
within 5.1 km of each other on Monday, June 16th at 12:41:41.2 UTC.  The two
will continue to make close approaches to one another every 96 minutes 46
seconds:

   Date    UTC  Time Norad       Name           Range (km) NdAng EphAge
 6/16/1997 12:41:41.2 12785 Cosmos 1300               5.1     2.8  +3.62
 6/16/1997 14:18:27.4 12785 Cosmos 1300               5.5    21.8  +3.69
 6/16/1997 15:55:13.6 12785 Cosmos 1300               6.4    37.4  +3.76
 6/16/1997 17:31:59.8 12785 Cosmos 1300               7.6    48.3  +3.83
 6/16/1997 19:08:46.0 12785 Cosmos 1300               8.9    55.7  +3.89
 6/16/1997 20:45:32.3 12785 Cosmos 1300              10.3    61.0  +3.96
 6/16/1997 22:22:18.5 12785 Cosmos 1300              11.7    64.8  +4.03
 6/16/1997 23:59:04.8 12785 Cosmos 1300              13.1    67.7  +4.09

 6/17/1997  1:35:51.0 12785 Cosmos 1300              14.4    69.9  +4.16
 6/17/1997  3:12:37.3 12785 Cosmos 1300              15.6    71.6  +4.23
 6/17/1997  4:49:23.5 12785 Cosmos 1300              16.8    73.1  +4.30
 6/17/1997  6:26:09.8 12785 Cosmos 1300              18.0    74.2  +4.36
 6/17/1997  8:02:56.1 12785 Cosmos 1300              19.1    75.2  +4.43
 6/17/1997  9:39:42.4 12785 Cosmos 1300              20.1    76.0  +4.50
 6/17/1997 11:16:28.7 12785 Cosmos 1300              21.0    76.7  +4.56
 6/17/1997 12:53:15.0 12785 Cosmos 1300              21.9    77.3  +4.63
 6/17/1997 14:30:01.4 12785 Cosmos 1300              22.7    77.8  +4.70
 6/17/1997 16:06:47.7 12785 Cosmos 1300              23.5    78.2  +4.77
 6/17/1997 17:43:34.1 12785 Cosmos 1300              24.2    78.6  +4.83
 6/17/1997 19:20:20.4 12785 Cosmos 1300              24.8    78.9  +4.90
 6/17/1997 20:57:06.8 12785 Cosmos 1300              25.3    79.2  +4.97
 6/17/1997 22:33:53.2 12785 Cosmos 1300              25.8    79.5  +5.03

 6/18/1997  0:10:39.6 12785 Cosmos 1300              26.2    79.7  +5.10
 6/18/1997  1:47:26.0 12785 Cosmos 1300              26.5    79.8  +5.17
 6/18/1997  3:24:12.4 12785 Cosmos 1300              26.8    80.0  +5.24
 6/18/1997  5:00:58.8 12785 Cosmos 1300              27.0    80.1  +5.30
 6/18/1997  6:37:45.2 12785 Cosmos 1300              27.1    80.2  +5.37
 6/18/1997  8:14:31.7 12785 Cosmos 1300              27.1    80.2  +5.44
 6/18/1997  9:51:18.1 12785 Cosmos 1300              27.1    80.2  +5.51
 6/18/1997 11:28:04.6 12785 Cosmos 1300              27.0    80.2  +5.57
 6/18/1997 13:04:51.0 12785 Cosmos 1300              26.9    80.2  +5.64
 6/18/1997 14:41:37.5 12785 Cosmos 1300              26.6    80.2  +5.71
 6/18/1997 16:18:24.0 12785 Cosmos 1300              26.4    80.1  +5.77
 6/18/1997 17:55:10.5 12785 Cosmos 1300              26.0    80.0  +5.84
 6/18/1997 19:31:57.0 12785 Cosmos 1300              25.6    79.9  +5.91
 6/18/1997 21:08:43.6 12785 Cosmos 1300              25.1    79.7  +5.98
 6/18/1997 22:45:30.1 12785 Cosmos 1300              24.5    79.5  +6.04

 6/19/1997  0:22:16.6 12785 Cosmos 1300              23.9    79.3  +6.11
 6/19/1997  1:59:03.2 12785 Cosmos 1300              23.2    79.0  +6.18
 6/19/1997  3:35:49.8 12785 Cosmos 1300              22.4    78.6  +6.24
 6/19/1997  5:12:36.3 12785 Cosmos 1300              21.6    78.2  +6.31
 6/19/1997  6:49:22.9 12785 Cosmos 1300              20.7    77.8  +6.38
 6/19/1997  8:26:09.5 12785 Cosmos 1300              19.8    77.2  +6.45
 6/19/1997 10:02:56.2 12785 Cosmos 1300              18.7    76.6  +6.51
 6/19/1997 11:39:42.8 12785 Cosmos 1300              17.7    75.8  +6.58
 6/19/1997 13:16:29.4 12785 Cosmos 1300              16.5    74.8  +6.65
 6/19/1997 14:53:16.1 12785 Cosmos 1300              15.3    73.6  +6.71
 6/19/1997 16:30:02.7 12785 Cosmos 1300              14.0    72.2  +6.78
 6/19/1997 18:06:49.4 12785 Cosmos 1300              12.7    70.4  +6.85
 6/19/1997 19:43:36.1 12785 Cosmos 1300              11.4    68.0  +6.92
 6/19/1997 21:20:22.8 12785 Cosmos 1300              10.0    64.8  +6.98
...

The elements I used were:

HST
1 20580U 90037B   97164.12191564 +.00000345 +00000-0 +21665-4 0 09693
2 20580 028.4663 063.7286 0014988 152.8368 207.3003 14.86459659192454

and

Cosmos 1300
1 12785U 81082A   97163.90546505 +.00000114 +00000-0 +94043-5 0 00859
2 12785 082.4866 316.8230 0017448 055.0692 305.2166 14.89002967854368

Haven't checked yet, but perhaps this pair is sunlit from a dark location at
one of the times of close approach ... --Rob