[net.sf-lovers] laser-water-rockets?

trc@houca.UUCP (10/26/83)

Does anyone know anything about the idea of using high-powered laser 
beams to launch space craft from earth?  My understanding of it is that
the craft would carry a load of water, (or some similar substance)
that could be super-heated and expelled.

Obviously not as elegant as a space elevator, but I wonder if a space 
mounted laser system might not be a good way to take a craft up from 
some altitude (perhaps transfer it from low-earth orbit).  I suspect 
that this would be primarily used for un-manned cargo ships, at least 
at first.  (Those high-powered lasers can *sting* if they should be 
mis-aimed slightly!)  Note that this might be feasible even if today's 
lasers couldnt punch all the way to the bottom of the atmosphere.  Thus, 
"star wars" technology is not required.  The lasers would be powered by 
"free" solar power, of course.  For a LEO to a geosynchronous orbit, I
would think that little more than a modified industrial strength laser 
and some highly accurate aiming equipment would be needed.  (Remember 
that one of the difficulties with the "star wars" concept is that the 
intended targets might take evasive action or use protective shielding - 
something *our* intended targets would presumably not do!)

It wouldnt seem to take too many bucks to put up such a sattelite, and 
then most anything we put up with the shuttle (perhaps even those ETs?)
could be boosted on up for little cost.  Evenually there might even
be a "ferry" craft, from LEO to geosynch.  A space station could be
built around the laser launcher.  This, if feasible, is something that
doesnt require the large investment or even as much new technology as 
a space elevator would require, and so would be a good "stepping stone" 
into space.

Does anyone know enough about rockets and the properties of water, to do 
some calculating of how much water would be needed to do various things?
Some interesting examples would be taking the ETs up from LEO to a secure
orbit, taking a craft from earth to LEO, or all the way to a non-decaying
orbit.  If the beam could punch through the atmosphere, could we power
commercial rocket-planes with this technology, at high altitudes?

	Tom Craver
	houca!trc