Subject: Re: Settle the moon first using tethers Date: 10 May 2004 19:35:23 -0700 From: vince@offshore.ai (Vincent Cate) Newsgroups: sci.space.policy Joe Strout wrote in message news:... >Yes, I understand all this, and it doesn't answer my question. I think >you've given me the anwser anyway, though. The payload's momentum >carries it forward, at the same rate as the tether tip. The only >acceleration the tether applies is directly towards the ballast. Right. That is a much more direct answer. :-) >It's fairly easy to see why this is in the case of a LEO tether; >somewhat harder to picture in the case of a rotovator, where the payload >is initially at rest with respect to the surface. But I guess in this >case it would mean, that the tether doesn't initially accelerate the >payload forward or backward; it lifts it pretty much straight up. In Vietnam the US military used something called the "Fulton Extraction System" to rescue a downed airman. They first dropped off a package. The guy would put it on and inflate a helium balloon that would take a line up some distance into the air. The plane would then fly back over and grab the line near the balloon. This would lift the stationary guy pretty much straight up, at least at first. The accelerations were not too bad if there was not much wind and the balloon was straight up. The guy would swing up behind the plane and then they would winch him in. This is like a very small scale rotovator that touches down. Some info at http://www.wpafb.af.mil/museum/history/rescue/res12.htm I have not found a web site showing close up pictures of it in use. -- Vince