Mir decay
---------
As you probably know, the de-orbit manoeuvres of Mir are now scheduled
for the early hours UTC of Friday, March 23. By my estimates over the
past week or more, Mir has been on schedule for a natural decay on or
about March 30. However, a geomagnetic storm (connected with a coronal
hole) has been active over the past day
(see http://www.sel.noaa.gov/today.html)
with the result that Mir's drag rate has increased by 50% or more above
what I expected. The increase is no doubt temporary, but meantime damage
is being done to Mir's natural life expectancy. If the current
instantaneous drag levels are sustained, the natural decay could come as
early as March 26.
With regard to the intended de-orbit manoeuvres, one question I have
been asked is: How long would Mir survive if the final "burn" to lower
its perigee from 159 km to 83 km failed completely, leaving it in the
intermediate 214 x 159 km orbit? In fact, I estimate that it would take
about 38 hours (or 26 orbits) to decay naturally from such an orbit.
_________________________
I have just updated my Decay Watch page with regard to the following two
decayers, now being predicted by SpaceCom. Check the page for predicted
elsets.
_____________________________________________________________________
Object: #22233 = 92- 79 C = GPS 2-16 r2 (PAD-D)
Decay predictions:
Source Prediction made Predicted decay at Latitude Longitude
UTC UTC deg deg
SpaceCom Mar 20 08:13 Mar 24 08:41 +-2d 21.1 N 168.8 E
SatEvo Mar 20 19:20 Mar 25 01:10 +-1.4d
Latest elset:
GPS 2-16 r2 3.0 1.5 0.0 6.5 d 3.1 772 x 148 km
1 22233U 92079C 01079.22516071 .06016402 12375-5 12933-2 0 8047
2 22233 34.4926 1.9893 0456125 81.9589 42.3047 15.35469841208494
Note: This enters eclipse while southbound near 33 deg N in the evening
and leaves eclipse, also southbound, near 32 deg S before dawn.
_____________________________________________________________________
Object: #26059 = 00- 3 B = Zhongxing-22 CZ-3A rocket
Decay predictions:
Source Prediction made Predicted decay at Latitude Longitude
UTC UTC deg deg
SpaceCom Mar 20 19:51 Mar 23 20:18 +-2d 22.3 S 152.9 W
SatEvo Mar 20 20:00 Mar 23 20:11 +-1d
Latest elset:
Zhongxing-22 CZ-3A r 1903 x 107 km
1 26059U 00003B 01079.54602573 .18772808 -36323-4 60383-3 0 5435
2 26059 24.5692 109.9486 1216052 258.8554 285.8577 13.68413341 12316
Note: Eclipse entry occurs northbound near 7 deg N in the evening. It
leaves eclipse while southbound near 21 deg N in the morning.
_____________________________________________________________________
Alan
--
Alan Pickup / COSPAR 2707: 55d53m48.7s N 3d11m51.2s W 156m asl
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 : Tue Mar 20 2001 - 12:58:32 PST