Larry J said the following:

>Satellite reconnaissance is good but it has a
>lot of limitations, largely due to predictability.
>Unless a satellite maneuvers, you can easily
>predict when it will fly over you. This allows
>you to take measures to hide what you're
>doing. This is nothing new.* Maneuvering
>burns propellant which impacts the satellite's
>operational life, so they don't maneuver any
>more than absolutely necessary.

In a previous life, I had a job doing orbital mechanics for low altitude satellites. These were the older ones that had a limited number of reentry vehicles carrying film spools. I recall a funny story I heard concerning what the USAF did with these vehicles after the last film spool was dropped. At that point the low altitude satellite was simply a useless camera with no film in it. The powers-that-be assigned control of the vehicle to a 2nd lieutenant, who would then change orbits to fly willy-nilly over Russia. He'd do this until the satellite was on the verge of running out of propellant and then dump it into the South Pacific. I remember that a special orbit mechanics package was setup to run on a separate minicomputer for these wild rides. The story went that the 2nd lieutenant did everything himself and was separated from actual operational missions.

This tale may have been urban legend. However I must confess to envying that 2nd lieutenant (how many people have a live orbiting spacecraft to play with?).

Gary