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From: al@vger.UUCP ( Informatix)
Newsgroups: net.space
Subject: Re: Next generation shuttle: electrically assisted take-off?
Message-ID: <328@vger.UUCP>
Date: Sun, 2-Feb-86 15:03:53 EST
Article-I.D.: vger.328
Posted: Sun Feb  2 15:03:53 1986
Date-Received: Tue, 4-Feb-86 03:15:14 EST
References: <8602010854.AA02457@s1-b.arpa>
Organization: UC Santa Cruz, CIS Dept.
Lines: 42
Summary: There are several practical problems to this approach.

In article <8602010854.AA02457@s1-b.arpa>, ST401385@BROWNVM.BITNET writes:
> 
>      There have recently been several postings relating to
> electromagnetic launch from the Earth's surface.
> Why not use an accelerator boost for a next-generation shuttle?
>      Rockets are not very energy efficient.  Most of the energy of the
> fuel goes to the exhaust.  

Energy is a very small fraction of the cost of space flight.  The vast
majority of the cost is engineering salaries.  Thus, minimizing engergy,
while helpful, is not decisive.  If you really want to reduce the
cost of space flight, build an inexpensive, first class CAD workstation
for space flight engineering.  Right now the MacIntosh, with a couple
thousand dollars worth of software and a hard disk, is a very good
system for the aerospace engineer but it needs special purpose 
analysis software.  Somebody ready to port NASTRAN to the Mac?

>      Suppose we boost a shuttle from a linear accelerator attached
> to the side of a mountain.

Apparently you haven't been on any tall mountains lately.  The weather
is awful, land slides are common, there's a lot of snow, sometimes
they are volcanically active, and support facilities are usually minimal.
Weather causes serious problems for the shuttle in Florida, think what
a really first class series of mountain storms would do.

> For an example, let's suppose this is Mount Kenya, a 5 Km
> tall mountain on the equator (the most efficient place to launch
> from, at least if you want equatorial orbits.)

Africa is pretty unstable politically, Otrag  (Ortag?) had to abandon
launch attempts in Africa as the result of a revolution.  In addition,
you need a lot of support services to launch satellites, better stick
to well developed industial countries, although Ariane seems to have
done OK in South America.  Also, a nearby seaport is extremely useful
for many payloads.

>      Is this idea totally nuts, or would it work?

The physics seems OK, although you need to get a lot more acceleration to
really gain much.  Shuttle launch maxes out at about 3g's so you could
rework your figures, operational problems are overwhelming though.