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Re: The Olympics

At 10:36 AM -0500 9/25/00, Paul O. Johnson, you wrote about Re: The Olympics:

In fact, satellite telescopes are not slewed to their target by spinning an
internal body the opposite way. Most satellites achieve attitude control
with gyroscopic reference systems. Three mutually orthogonal gyroscopes are
used to define an inertial reference frame. Torquing motors are then used to
rotate the satellite with respect to this frame. The gyro reference frame is
maintained against the stars.

But no 'impulse engines' (rockets) are used. It is 'only' the
electric motors acting in concert with rotating masses that gets the
aiming done. In this sense it IS an angular momentum exchange
process. (But we WON"T be tempted to reify angular momentum by saying
that it is 'transferred' back and forth between the stable reference
frame on the 'scope!)

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