When I was at Uni, in the 60s, we had a brief course on 'Space Physics'. It had a hotch potch of topics in it and one of them was about actually launching satellites. 'In those days', apparently, vehicles were rotated during the launch and this rotation had to be eliminated once they were in orbit. I have a vague memory of being told about about a technique that was described for slowing or stopping the rotation which consisted of a mass on a tether that was wrapped around the rocket / satellite. As it unwound, it was supposed to re-distribute the angular momentum to leave part of the load not spinning. Does anyone know about this? It has been bugging me for years because I just can't remember the details or work out from scratch what they did.