I agree with Tony Beresford and Ed Cannon in thinking it very probable
that the event was the re-entry of the Proton rocket used to launch a
trio of Uragan global positioning satellites, members of the GLONASS
system, a few hours earlier from Baikonur.
Only two element sets have (so far) appeared for this object:
Uragan Proton r 160 x 135 km
1 26990U 01053D 01335.99111456 .00678177 77909-5 10000-4 0 15
2 26990 64.8508 16.1658 0018997 343.0783 16.9770 16.47070965 14
Uragan Proton r 176 x 106 km
1 26990U 01053D 01336.11317538 .01791896 78820-5 10000-4 0 28
2 26990 64.8961 15.7767 0053422 2.4025 3.3366 16.49346660 33
To the extent that these show the apogee height increasing from 160 to
176 km, these are inconsistent unless the rocket manoeuvred between the
epochs of the elements (at Dec 1 23:47 UTC and Dec 2 02:43 UTC
respectively). In fact, I suspect that there was no manoeuvre and that
the discrepancies are due to SpaceCom's difficulty in linking its fixes
while the object was decaying rapidly due to a very low perigee near
its northbound crossing of the equator.
If we assume that it did decay a little more than one revolution later,
I estimate that the following elset may be near the mark for the
beginning of that final rev, at a northbound equator crossing over the
eastern Pacific at 04:09 UTC:
Uragan Proton r 139 x 103 km
1 26990U 01053D 01336.17272658 1.05297290 82222+1 36526-3 0 90026
2 26990 64.8948 15.5425 0027486 2.3749 357.6381 16.57002316 49
If so, the following table gives the ground track as it reached and
swept over the American mainland:
Time (UTC) Lat Long
h m s deg N deg W
4 14 0 19.9 109.3
4 14 30 21.8 108.5
4 15 0 23.6 107.5
4 15 30 25.5 106.6
4 16 0 27.3 105.6
4 16 30 29.1 104.6
4 17 0 31.0 103.6
4 17 30 32.8 102.5
4 18 0 34.6 101.4
4 18 30 36.3 100.2
4 19 0 38.1 98.9
4 19 30 39.9 97.6
4 20 0 41.6 96.2
This would have taken it over Lubbock, Texas, shortly before 04:18 UTC
and on NNE-wards over western Oklahoma and Kansas towards Lincoln and
Omaha Nebraska which would have been reached at 04:20 were it still in
orbit.
SpaceCom posted two decay notices for this:
Source Prediction made Predicted decay at Latitude Longitude
UTC UTC deg deg
SpaceCom Dec 2 02:34 Dec 2 04:41 +-3h 50.6 N 20.0 E
SpaceCom Dec 2 04:46 Dec 2 04:16 +-7m 27.0 N 106.0 W
The latter one is consistent with the decay along the arc predicted
above.
Alan
--
Alan Pickup / COSPAR 2707: 55.8968N 3.1989W +208m (WGS84 datum)
Edinburgh / SatEvo & elsets: http://www.wingar.demon.co.uk/satevo/
Scotland / Decay Watch: http://www.wingar.demon.co.uk/satevo/dkwatch/
*
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This archive was generated by hypermail 2b29 : Sun Dec 02 2001 - 07:03:39 EST