Third way

From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of Omar E. Vega

> It's possibe to change the source of power from a ground
> based laser to a geosyncronic satellite?

You bet. In fact, that might not only be a good setup for spacecraft
ascending to orbit, but for long-range passenger jet travel. One would
take off with traditional jet engines, but once you've ascended to
cruising altitude (and the satellite locks on) you switch over to a
beam-intercepting heat exchanger on top.

When I first heard about this proposal, my first reaction was, "Great,
then if your power beam misses its target when the aircraft is over
land, then you've got a nice long line of forest fires." But proponents
say you could choose a laser frequency which is strongly absorbed by
water vapor. Jets cruise above the biggest part of the water vapor in
the atmosphere, but such a beam would be strongly attenuated by the time
it reached the ground, even on a clear day.

O'Neill wrote a bit about this in "2081: A Hopeful View of the Human
Future".

Regards,

Mike Combs