From: vince@offshore.ai (Vincent Cate)
Newsgroups: sci.space.tech
Subject: Re: Lunar Sample Return via Tether
References: <b0ce55f4.0312080607.61693634@posting.google.com> <20031209194336.06226.00001965@mb-m19.aol.com> <9186edb5.0312100949.3c86ca20@posting.google.com>
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vince@offshore.ai (Vincent Cate) 
> However, you can easily control a tether's rotational momentum, when 
> near a gravitational body, by winching the tether in and out as it is 
> going up or down relative to the body.  If you want to rotate faster 
> you let it out on the down side and winch in on the up side so it spends
> more time going down (and pulled faster) than going up (and pulled slower). 
> So rotational momentum is an easily solved problem.

The real algorithm is to pull in when the tether is vertical and 
let out when it is horizontal relative to the body.  The method
in the paragraph above does not work.  The working algorithm comes
from the Tether Guidebook and I have confirmed it by simulation.

But it is true that you can control your rotational momentum without 
using any reaction mass when near a gravitational body.

   -- Vince