KING%KESTREL@sri-unix.UUCP (04/09/84)
From: Richard M. King <KING@KESTREL> Anyone know why the following wouldn't work? (or whether it would) 1> set MMU to be inertially stabilized 2> grab a solar panel of slowly rotating satellite 3> hold on until satellite stops By my calculations (assuming a moment of 500 slug-feet) the satellite has angular momentum that would require 10 foot-pound-seconds to stop. Doesn't really seem to me to be beyond the reach of normal human strength, even in a space suit (and he's supposed to be an amateur weight lifter). It also doesn't seem likely to me that this kind of force would break off the panels. If someone had a bit more chutsbah they could plan to make contact with a part of the satellite that was coming towards them and kill the rotation that way! Dick -------
hennessy@nmtvax.UUCP (04/15/84)
<> >From: Richard M. King <KING@KESTREL> > > > Anyone know why the following wouldn't work? (or whether it would) > > 1> set MMU to be inertially stabilized > > 2> grab a solar panel of slowly rotating satellite > > 3> hold on until satellite stops > > By my calculations (assuming a moment of 500 slug-feet) the satellite >has angular momentum that would require 10 foot-pound-seconds to stop. >Doesn't really seem to me to be beyond the reach of normal human strength, >even in a space suit (and he's supposed to be an amateur weight lifter). It >also doesn't seem likely to me that this kind of force would break off the >panels. Just holding on to the satelite by a human being would not cause the satelite to stop. Instead the astronaut and the satelite would both come to a new equililbrium where they rotate with a constant angular velocity. This new velocity would be VERY difficult to calculate since the moment of inertia of the system is extremely non-trivial. I suppose the astronaut could give the satelite a "shove" in one direction to attempt to slow the rotation, which would also give him/her a large rotation in the opposite direction. To get the above calculation there must be a object to give the angular rotation to and a source of friction. Both happen on good ol' Earth where it could be done but not in free fall. Sincerely; Greg Hennessy ..ucbvax!unmvax!nmtvax!hennessy
kcarroll@utzoo.UUCP (Kieran A. Carroll) (04/19/84)
* When the astronaut grabbed the solar max satellite in an attempt to stop its rotation, he wasn't planning to change the rotation rate by "giving it a shove". Instead, he was planning to activate the "attitude hold" feature of his manoeuvering unit. The gyros in the MMU would sense that their reference platform was rotating, and send out commands to the MMU's gas jets to apply a torque in the direction required to stop the rotation (I assume). -Kieran A. Carroll ...decvax!utzoo!kcarroll