Right Place, Right Time

So far, we've only been concerned with reaching the orbit of the GPS satellite. We haven't considered how to actually get our satellite to the right place at the right time! How do we know when (or where) in our low Earth (shuttle) orbit to fire the booster to launch the GPS satellite?

To figure this one out, we need to look at both the desired period of the GPS satellite and the period of our shuttle orbit. We can express our answer as a desired angular separation between the target GPS location (where it would be if it were already in orbit) and the shuttle location at the time when the GPS booster is fired. An example of a possible answer is depicted by this figure.

#1 Determine the angle between the desired GPS location and the shuttle location when the GPS booster must be fired.

Angle = o

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