RE: starship-design: FINDING A COMMERCIAL DEVELOPMENT PATH (http://infinity.msfc.nasa.gov/Public/pp0

["L. Parker" <lparker@cacaphony.net>]

Nels,

> 	Lee,
> they mentioned EM launchers at this site, but restricted them
> to getting
> fuel material to orbit for the earth environment.  There is some idea
> that a long (100 to 300km) launcher, near the equator could be
> sufficiently gentle to be an ultra cheap general purpose
> launcher.  the
> "meteor in reverse" problem could be solved by suspending the launcher
> from hot air-balloons above much of the atmosphere (50% of the
> atmosphere is below 18,000ft).  This proposal, though a difficult
> problem, doesn't strike me as being too terribly implausible. Another
> idea would be to use a hybrid EM/Rocket.  A reusable SSTO is
> launched as
> a projectile to a given height, at some point, it lights its
> rockets and
> climbs the rest of the way to orbit.

I think they are only being looked at for the moon because of the lower
escape velocity and the presence of abundant cheap power. While such a
scheme may be doable on Earth, it would be prohibitively expensive and would
be restricted to small, durable payloads - such as raw ore. Hardly something
we need to launch into space when it is so readily available there already.

Lee