Mass driver for commodity supplies

--- In spacesettlers@yahoogroups.com, joe@... wrote:
>
> I'd like to see citations for that. Launching from Earth's surface to
> LEO with a mass driver is enormously difficult. The frictional heating
> involved is the same as when decelerating from orbital velocity to
> zero, e.g. on reentry. But there, you're *trying* to shed energy...

Hi Joe,

Frictional heating and aerodynamic drag are, in fact, two of my
biggest concerns for this type of launch system. Sorry if I sounded
like a conspiracy theorist - I meant to sound more like a status quo
theorist. In this regard I'm thinking of how NASA has held on to the
Space Shuttle for nearly thirty years as "the" answer for getting into
space. The Space Shuttle is a great technical achievement but NASA
seems to have come around to the idea that there may be better ways of
doing the same job.

Dave H. mentioned the use of an apogee kick motor, which is
essentially the method Burt Rutan used in his Spaceship One design.
Such a hybrid vehicle for resupply and mass transport to LEO is more
along the lines of what I had in mind.

I believe the Army built and tested a super-gun (for high altitude
research) in 1966 that achieved apogees of 180 Km using a 100 Kg
projectile and conventional artillery technology with a muzzle
velocity of 2100 m/s (www.lifeboat.com/em/chapter1.pdf).My google
search also turned up articles that indicate the Navy is trying to
develop EMLS for shipborne missile launches (I believe it was in a
public announcement by Lockheed).

So, leaving thoughts of conspiracy behind, I'm wondering how close
we are to developing a practical EMLS for resupply and mass transport
to LEO. Anyone have any thoughts on this?

Chris