Re: Large number of debris objects from Delta 4 Rocket

From: Mike McCants (mmccants@io.com)
Date: Thu Nov 16 2006 - 18:45:05 EST

  • Next message: Ed Cannon: "possible re-entry on October 1?"

    There are now almost 300 tles for the 60 objects that first
    showed up on Nov. 14.
    
    The mean motion for the payload and its rocket were approximately
    14.13 revs/day.  The mean motions for the debris objects range from
    14.17 through 14.25 to about 14.34 revs/day.  This seems like a fairly
    small "dispersion".  So my theory (today) is that the rocket started
    its disposal/re-entry burn and burned for only a very short time
    and changed its mean motion from 14.13 to 14.25 revs/day.  Then some
    time later, the rocket exploded.  The main piece of the rocket (yet
    to be cataloged) would remain in a 14.25 revs/day orbit.  When it
    is cataloged, it will have a much lower drag term compared to the
    60 tiny pieces.
    
    The theory of multiple objects with different velocities (but the
    same energy) leaving from a single point could lead to orbits that
    intersect twice - once at that point of origin and again about
    one-half of an orbit later.  But objects with higher or lower energies
    should be above or below the objects with the same energy at the point
    that is about one-half way around the orbit.  Because I am extrapolating
    backwards in time from Nov. 14, 15, or 16 to Nov. 4 with tles that
    have non-zero and changing drag terms, the agreement among the
    extrapolated orbits on Nov. 4 is not very high.
    
    Many of these tles seem to go through the following two volumes
    in time and space:
    
    Nov. 4, from 15:55 to 16:05 UT - height 500 to 520 miles
    latitude 30 to 35 south, longitude 162 west.
    
    Nov. 4, from 17:00 to 17:10 UT - height 500 to 520 miles
    latitude 65 to 80 degrees north, longitude 40 east -20/+70 degrees.
    
    Note that the launch was at 13:53 UT and the disposal burn was
    scheduled for 15:44 UT.  So 16:00 is only 16 minutes later than that.
    The predicted position for the rocket at 16:00 UT would have been:
    height 526 miles, latitude 28.9 south, longitude 161 west if no
    burn took place.
    
    However, there are a number of pieces that fit the 17:05 UT time
    better than the 16:00 UT time and only a few pieces that fit the
    16:00 time better than the 17:05 time.  Of course the 17:05 time
    is 81 minutes after the scheduled burn.
    
    Mike McCants
    
    -------------------------------------------------------------------------
    Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive:  
    http://www.satobs.org/seesat/seesatindex.html
    



    This archive was generated by hypermail 2b29 : Thu Nov 16 2006 - 18:49:51 EST