Decay watch: 2001 Mar 20

From: Alan Pickup (alan@wingar.demon.co.uk)
Date: Tue Mar 20 2001 - 12:54:58 PST

  • Next message: Bjoern Gimle: "Decay?"

    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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