Milstar 4 elements - Centaur propellant dump alert

From: Ted Molczan (molczan@home.com)
Date: Tue Feb 27 2001 - 13:34:45 PST

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    I still do not know whether or not the Centaur upper stage will perform a
    propellant-dump, but the elements and other information in this post can be
    used to determine where to look for it.
    
    Using the ILAM information provided by Keith Stein:
    
    http://www2.satellite.eu.org/seesat/Feb-2001/0290.html
    
    I have derived the following elements, based on today's successful launch,
    which lifted off at 2001 Feb 27 at 21:20 UTC:
    
    Milstar 4       23.0  5.0  0.0  3.5 d
    
    LEO Parking orbit insertion
    1 70001U          01058.89768519  .00000000  00000-0  00000-0 0    08
    2 70001  28.5970 301.3030 0008470 116.6180  10.8720 16.27228965    09
    
    Transfer orbit insertion
    1 70002U          01058.93800926  .00000000  00000-0  00000-0 0    03
    2 70002  26.6860 301.5560 7306180 352.0530   1.6490  2.26971460    09
    
    Spacecraft separation
    1 70003U          01059.16306713  .00000000  00000-0  00000-0 0    05
    2 70003   4.5010 345.6470 0000480 326.3210 165.2540  1.00342419    07
    
    No objects are expected to be left behind in the LEO parking orbit or the
    transfer orbit.
    
    The Centaur's final orbit insertion burn is scheduled to begin on 2001 Feb 28
    at 03:42:24 UTC, for a duration of 2 min 12 s. I do not know how visible the
    plume will be, but this event will be illuminated by the sun, and the sun will
    have set for all of North America. Use the 70002 elset for this event.
    
    I do not know whether or not the Centaur will perform a propellant-dump, but if
    it does, then it is likely to occur soon after payload separation, on 2001 Feb
    28 at 03:54:49 UTC. The circumstances of visibility would be about the same as
    for the final orbit insertion burn. Use the 70003 elset for this event.
    
    Ed Cannon and Mike McCants observed the propellant-dump of the 97068A / 25034
    launch. When the plume was first spotted, about 21 minutes after payload
    separation, it was about 1st magnitude, and about 1 deg in diameter. It was at
    a range of 19100 km, and about 85 percent illuminated. For the full account,
    see Mike's SeeSat-L post, "We saw the Centaur fuel dump!":
    
    http://www2.satellite.eu.org/seesat/Nov-1997/0141.html
    
    Here is another account of the same event:
    
    http://www2.satellite.eu.org/seesat/Nov-1997/0147.html
    
    Milstar 4's separation is to occur at 260.45 E longitude, which equals 99.55
    deg W. Spaceflight Now reports that the U.S. Air Force stated that the
    payload's final longitude will be 90 deg W.
    
    Ted Molczan
    
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