Absolute accuracy limits of a transfer orbit propagator

The accuracy with which an orbit under moderate or high amounts of atmospheric drag may be propagated for several years, contains an absolute limit, due to our present inability to predict solar and geomagnetic activities for long periods of time. The resulting uncertainty in atmosphere model inputs cause errors in the orbit evolution than are an order of magnitude worse that those inherent in a semianalytic orbit propagator. Therefore, use of more accurate software, such as a numerical integrator, is pointless. The subject orbit for this error analysis is a geosynchronous transfer orbit, with a nominal perigee altitude of 400 km, and launch in mid-1990, near the maximum of solar cycle 22.