Re: New Iridium Elsets

Bjoern Gimle (bjorn@tt-tech.se)
Fri, 15 May 1998 13:31:52 +0200

Keith Stein <kstein@launchspace.com> wrote:
> >
> >> Delta/Iridium Nominal Orbit Data
..
> >> PERIOD (MIN):                       97.478           97.267
> >> ...
> >> PERIOD (MIN):                       97.267           97.172
> >> ...
> >> PERIOD (MIN):                       97.113           92.734
> >> ...
> >(snip)
> >
> >

Jim Varney <jamesv@softcom.net> wrote:
> >"
> >Roughly translated to TLE's (with wild guesses for drag) I get:
> >
> >2 90000 086.583  265.2570 0003410 119.1820 253.8990 14.77260425000000
..
> >2 90000 086.580  265.2550 0013920 194.3570 215.7060 14.80461050000000
..
> >2 90000 086.579  265.2530 0017460 219.0050 206.4410 14.81905132000000
..
> >2 90000 086.579  265.2510 0018820 241.5390 199.2790 14.82802449000000
..
> >2 90000 086.579  265.2490 0017280 262.9760 193.2100 14.82899900000000

My guess is that the given periods are nodal. Iridium perigees precess
by +3.6 degrees/day. Correct me if either of these assumptions are wrong!
If so, Jim's MM should be reduced by 0.01:

Iridium SV4 SEP                                  637 x 610
1 90004U 98999D   98135.95064815  .00000600 +00000-0  60000-4 0 00000
2 90004 086.579  265.2510 0018820 241.5390 199.2790 14.81802449000008
Iridium SV5 SEP                                  635 x 611
1 90005U 98999E   98135.95354167  .00000600 +00000-0  60000-4 0 00003
2 90005 086.579  265.2490 0017280 262.9760 193.2100 14.81899900000009
Iridium SV3 SEP                                  639 x 614
1 90003U 98999C   98135.94775463  .00000600 +00000-0  60000-4 0 00006
2 90003 086.579  265.2530 0017460 219.0050 206.4410 14.80905132000004
Iridium SV2 SEP                                  641 x 621
1 90002U 98999B   98135.94486111  .00000600 +00000-0  60000-4 0 00004
2 90002 086.580  265.2550 0013920 194.3570 215.7060 14.79461050000005
IRIDIUM xx, 15 May 98, 21:28:30 UT               641 x 626
1 98765U 980xxA   98136.07113438  .00000026  00000-0  00000+0 0    17
2 98765  86.5808 257.4270 0011126 223.7504 136.2836 14.78706595    26
Iridium SV1 SEP                                  644 x 639
1 90001U 98999A   98135.93791667  .00000600 +00000-0  60000-4 0 00007
2 90001 086.583  265.2570 0003410 119.1820 253.8990 14.76260425000001

in decreasing MM order, heights/checksums by Orbitel.exe, Ron's
initial elset included.

There will be five dense flare tracks over the Baltic Sea  around 00:20 UT,
if they launch on time, and the satellites orient themselves quickly.
I will be travelling tonight, but I will be too far east when flares hit!
Still, I'll try to see them. 

SeeSat Hypermail appears to be silent at the moment - could someone (Ron?)
mail elsets to my b_gimle@usa.net address, so I have a chance to search
from Helsinki Sunday morning also?

-- 

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