[Ravenstar]

My bachelors degree was Math but I really am not yet in the mood to do that calculation. At the Texas point is when I was told they were 38 miles up.

Ravenstar

[Erasmus]

Let us assume that the shuttle was 50 miles up over California, and for simplicity's sake, that the earth is a sphere with a radius of 4000 miles.

Then, you could see the shuttle on your local horizon, barring obstructions of course, from a distance of about 630 miles.

The furthest simultaneous observer would be 630 miles exactly on the other side of the shuttle from you, for a maximum separation of 1260 miles.

Ergo, there would be a brief time, perhaps a minute or two, during which the shuttle would be between California and East Texas and be unobservable from the ground in either place.

This is all rough calculation on the back of an envelope (actually, the front of an HP-42S <)B^).