Re: Updated 96072B elements

Bjoern Gimle (
Sun, 12 Jan 1997 15:35:00 +0100 (MET)

Ted Molczan wrote: 

>Here are Pierre's latest elements:
>USA 129 r        9.8  3.0  0.0  3.0 v
>1 24681U 96072  B 97 09.50886640  .01078668  00000-0  95304-4 0    01
>2 24681  97.8345  76.3285 0479853  96.1715 269.3145 15.33990437    09
>The object was about 36 s early relative this elset at about 96011.5,
>so it can be expected to be even earlier on the 12th.

The fact that the rocket is decaying more rapidly is interesting.

Ted, Pierre and others have expressed surprise at the low decay rate
so far, and Pierre's elsets have been very consistent since 97001.58,
so there is no reason to suspect the perigee height is in error.
My interpolation of his MM gives ndot2 increasing from 0.00898 to
0.01087 on Jan.09, closely matching the elsets, and Bstar for SGP4
model probably matches those.

With these elsets, and a standard atmosphere, I have estimated an
average area/mass ratio of 0.0039 m2/kg. Disregarding the possibility
of a heavy payload still attached to the rocket, this would mean
that the rocket has been aligned along the direction of motion, at
least near the perigee. But the flashing/variation observed should
indicate there was some rotation.

Except for this question, the higher decay rate should indicate  that
the rocket finally is showing its average area in the direction of motion,
and this should hopefully be apparent in the visual characteristics.

I will not be able to see the rocket before the decay (further
observations will be needed to see if the higher decay rate 
continued, before new decay estimates are made), but the payload
will rise sunlit above my horizon on Feb.01. I have not yet checked
when it will rise high enough to be seen in 7*50 binoculars. 

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