Possible Iridium Elset Problems

Ron Lee (ronlee@pcisys.net)
Fri, 14 Nov 1997 19:22:10 -0700

Iridium 43       3.0  0.0  0.0  6.0 d            649 x 624 km
1 25039U 97069A   97316.08479840 -.00933363  00000-0 -13961+0 0   186
2 25039  86.5490 132.5259 0018158 253.2675 106.6486 14.77692554   453
Iridium 43       3.0  0.0  0.0  6.0 d            643 x 628 km
1 25039U 97069A   97316.69406682 -.00048946  00000-0 -68208-2 0   201
2 25039  86.5793 132.2883 0011050 211.7976 148.2021 14.78117505   542

I thought I had a problem with Rob's Iridflar when I had IR 43 flaring
about 4 minutes after the others.  I had see all five that morning and
they were not that far apart.   Skymap confirmed that they were close.

The problem is that I was using a different set of Iridium elsets than for
Iridflar, hence did not catch the elset problem (Rob did).   Looking at the
mean motion in the elsets above and the epoch times, the first elset is 
apparently bad.

Someone else reported a "problem" with Iridflar like this recently and I
suspect they also used a "bad" elset.   Just a note that this may be more 
common than desired so folks should be aware of potential problems.  It 
may only affect new launches during the period from parking to operational
altitude.  It also reminds me that if one of Rob's programs seems wrong, I
need to look to other causes first!

Ron