Re: Distant satellite
Mike McCants (mikem@fc.net)
Mon, 8 Dec 1997 00:25:12 -0600 (CST)
>94004C
>1 22987U 94004C 94104.94558226 -.00001003 +00000-0 +10000-3 0 00321
>2 22987 067.0741 059.5229 9058578 202.4707 043.9901 00.46882193001010
I have run 2 (independent) programs and they agree that the orbit
of this object intersected the Earth's surface only a few weeks
after the epoch of this elset.
>1 90000U 97000 A 97339.46596080 .00000000 +00000-0 +00000-0 0 00000
>2 90000 066.3122 250.4967 8611650 336.2076 000.0000 0.41258420000000
>The elements below are, I'm afraid,
>in the J2000 equator frame rather than the usual B1950 one.
The usual is epoch-of-date. I adjusted the RAAN by -0.04 and came up
with:
1 90000U 97000 A 97339.46547469 .00000000 00000-0 00000+0 0 03
2 90000 66.3122 250.4567 8611650 336.2076 .0000 .41258420 00
Then I tried adjusting the mean motion and the argument of perigee
and came up with:
1 90000U 97000 A 97339.46629645 .00000000 00000-0 00000+0 0 00
2 90000 66.3122 250.4567 8611650 335.9406 .2670 .41758420 03
This seemed to fit the observations just as well.
(Disclaimer: my program is incapable of working with such accurate
observations.)
This would lead to a different time of prediction by about 30 minutes
tonight.
Predictions for me for tonight:
*** 97 Dec 7 Sun evening *** Times are CST ***
U MAG HGT ALT AZI HRS MIN R A DEC RANGE
128 13.0 46960 72 343 10 45 2 46.9 47.2 47144
129 13.1 48956 70 328 11 15 2 48.9 45.9 49172
130 13.2 50868 67 317 11 45 2 50.7 44.7 51153
131 13.3 52699 63 309 12 15 2 52.4 43.6 53093
Moving on out to 50000 miles with a magnitude of 12, 13, 14 or ?
Tomorrow night - apogee at 84000 miles.
Here is an interesting entry from Joel Runes' catalog:
Phobos 1 ESCAPE TRAJECTORY
1 19281U 88058A 88189.82152778 -.00000186 00000-0 00000-0 0 03
2 19281 50.8034 202.3051 8765244 10.5547 6.5019 0.44066780 00
But it would seem that an orbit like this could not evolve into
the observed orbit.
If I try to use this orbit:
1 90000U 97000 A 97339.46547469 .00000000 00000-0 00000+0 0 03
2 90000 66.3122 250.4567 8611650 336.2076 .0000 .41258420 00
and I try to go backwards in time (my program is not set up to
do this, so I am manually iterating), I end up with an eccentricity
that gets larger and intersects the Earth about 2 years ago:
1 90000U 97000 A 95340.91596080 .00000000 +00000-0 +00000-0 0 00
2 90000 63.8122 263.4967 9100000 326.2076 000.0000 0.41258420 00
Mike McCants