Good analysis, I think. But there is one thing I do not know: Are the collisions between the gas molecules and the S/C elastic or inelastic? That would certainly affect the coefficient of drag. Doug NA1DB ---- Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA. To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org