Two close encounters

ROB MATSON (ROBERT.D.MATSON@cpmx.saic.com)
5 Sep 1997 17:16:50 -0800

I've found two very close encounters that I thought were worth mentioning. 
The first is between Iridium 16 (#24841) and ERS-2 R/B (#23561), which will
occur on 9/6/97 @ 14:53:49.45 UTC at a range of 0.2 km!  I used the latest
orbital elements from OIG for this prediction:

Iridium 16
1 24841U 97030F   97248.16457275 +.00000044 +00000-0 +85063-5 0 00913
2 24841 086.4006 129.1668 0003273 028.5384 331.6001 14.34216130011374
ERS-2 R/B
1 23561U 95021B   97248.25038646  .00000045  00000-0  31651-4 0  2215
2 23561  98.3924 312.3450 0006440 195.3231 164.7758 14.33320284124364

The TLEs for #23561 will be 1.37 days old at the time of close approach.

The other encounter is between Delta 7925 R/B (#24809) and Tiros N (#11060)
which will occur on 9/6/97 @ 21:17:07.14 UTC at a range of 0.7 km.  Elements
used were:

Delta 7925 R/B
1 24809U 97025B   97248.14291234 +.00000153 +00000-0 +21718-4 0 00355
2 24809 026.2971 211.3855 0676102 111.7465 255.6360 13.27600864014250
Tiros N
1 11060U 78096A   97248.11510022  .00000045  00000-0  44108-4 0  7998
2 11060  98.5118 273.9241 0011403 125.4245 234.7994 14.15733253189619

I haven't checked yet to see where above the globe these two encounters occur.
 --Rob