Progress 59 decay estimate

From: Ted Molczan via Seesat-l <>
Date: Wed, 6 May 2015 21:59:29 -0400
Using the numerical integrator in GMAT 2014a, I found that Cd=2.2 and A/m=0.0032 m^2/kg are sufficient to account for
the decay over the span of USSTRATCOM's TLEs of epoch 15125.98285285 and 15126.89953602. 

Allowing the propagation to continue until decay, results in impact (10 km altitude) on 2015 May 08 near 03:17 UTC. The
uncertainty is 6 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. Taking into account the USAF's space weather forecast for this period (much lower
geomagnetic activity than today, and a small increase in solar flux), moves the time of impact to 05:41 UTC on the same

I converted the epoch 15124.87998146 TLE 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

Ted Molczan

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Received on Wed May 06 2015 - 21:00:17 UTC

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