Favored decay latitude?

Mark Hanning-Lee (markhl@prodigy.net)
Wed, 02 Dec 1998 15:03:26 -0800

I've noticed that many reentry predictions on the list seem to predict
decay soon after an equator crossing.

Why would a sat in a roughly circular orbit tend to decay at any
particular latitude? Does a decaying sat feel significantly more drag at
low latitudes? If so, why is the atmosphere number density higher there;
is it just the greater insolation?

(I appreciate that a sat in a very eccentric orbit decays near perigee,
which makes sense to me.)

Thanks for your replies, Mark