Progress 59 decay estimate

From: Ted Molczan via Seesat-l <seesat-l_at_satobs.org>
Date: Thu, 7 May 2015 14:30:05 -0400
In my previous message, the prediction uncertainty is incorrect. It should be 2.0 h.

Here is a new prediction:

Using the numerical integrator in GMAT 2014a, I found that Cd=2.2 and A/m=0.00295 m^2/kg are sufficient to account for
the decay over the span of USSTRATCOM's TLEs of epoch 15127.44781874 and 15127.69084686. 

Allowing the propagation to continue until decay, results in impact (10 km altitude) on 2015 May 08 near 02:03 UTC. The
uncertainty is 1.9 h, based on the rule of thumb of 20 percent of the estimated time remaining to decay, measured from
the epoch of the latter of the two TLEs. For both the calibration of A/m and propagation to impact, I used a rough
average of observed and forecast space weather.

I converted the epoch 15127.44781874 for propagation by GMAT using TLE Analyzer 2.12. I configured GMAT to use its
Dormand-Prince 78 numerical integrator, with the EGM-96 gravity model (degree 90, order 90), and the MSISE90 atmosphere
model.

Ted Molczan


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Received on Thu May 07 2015 - 13:30:53 UTC

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