Mass driver for commodity supplies

Joe - although the heating intensity is very high it
only lasts for a very short time. That is why I
mentioned a new ceramic coating, however Dr. Kolm's
original design allowed for ablation of about 3% of
the total mass during launch.

Chris - the main reason why it hasn't been attempted
is as you suggest, momentum of the current space
industry and their fixation to rockets. A second
reason is the cost of the system. It would be pretty
high, with an unproven technology, and very limited
unit payload. In fact it would not be financially
viable without Space Solar Power Satellites. Resupply
just doesn't make it. Even adding a Space Gas Station
doesn't quite make it, although it becomes very close.

regards,

Dave Handwerk

--- Chris Smyth wrote:

> --- 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
>

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