Re: Large number of debris objects from Delta 4 Rocket

From: Mike McCants (
Date: Thu Nov 16 2006 - 18:45:05 EST

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    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
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