"Jeff" wrote in message
...

The "craft" was the Einstein Observatory, and orbiting x-ray
telescope. The gyros are called CMG's, control moment gyros -

"a gyroscope, usually much larger than a gyro sensor, mounted on
a single or double gimbal and used to generate control torques.
The torques are generated by commanding gimbal angle rates that
result in inertial motion of the CMG spinning wheel and
accompanying gyroscopic reaction torques on the vehicle
structure."

Ooops!

Interesting people we meet round here. Understood completely.

My previous history was aeronautical systems - in the wider
sense - many moons ago.

JimB