From: bwhite@oucsace.cs.ohiou.edu (William E. White )
Newsgroups: alt.pagan
Subject: Re: Space, the final frontier
Date: 2 Jan 93 04:02:39 GMT
Organization: Ohio University, Computer Science Department

In article <1993Jan1.214231.14865@nntpd.lkg.dec.com> boylan@sltg04.ljo.dec.com (Steve Boylan) writes:

>Well, let me see . . .  Grabbing an envelope out of the trash, 5 mi/sec.
>works out to 8,046 meters/sec.  Can we be friends here, and round that
>off to 8 km/sec.?  At 1 g, you'd need to accelerate for 821 seconds
>to reach that velocity (about 13 minutes).  The length of your railgun
>would therefore have to be 6,605,602 meters long.  Yes, that's six
>MILLION meters - 6,606 kilometers, or about 4,000 miles.  It's
>3,000 miles from Boston to San Diego.

Uh .... excuse me?  Whoever said that we were going to accelerate at 9.8
m/s^2?  I mean, come on, a handgun accelerates bullets faster than that,
and for that matter you can probably accelerate faster than that (at least
for a while) in a decent rocket or even a jet.
The whole point of railguns is very very rapid acceleration.  Much more
force than 1G.  Which is why cargo is emphasized rather than people.

Let's assume you're accelerating at 8000 meters/second, which is easily
within range of railguns.  This takes, of course, 1 second to get up to
speed; in that second we travel 8000 meters (simply enough).  Now this is
cake, we can bend it into a logarithmic spiral for that matter.  Heck,
8000 m/s is really slow for railguns but I'm assuming a heavy payload
and/or using a coilgun instead.

Plus which, if you've got a factory on the moon, then what you do is have
it automated, sending off packages via coilgun/railgun which drop into
Earth's gravity well and then pop out a chute and glide down.  Heck, the
US government did that with film canisters from spy satellites.  Anyway
the escape velocity on the moon is peanuts compared to Earth; and that's
where the real gain in space exploration is -- moving the industry off-
planet where it can't destroy the ecosystem anymore.

>Of course, people probably wouldn't feel too happy about being
>accelerated at 10 g, even for so short a time as 82 seconds.  And
>would anybody out there feel like computing the drag from the
>atmosphere on a capsule with a 9-foot diameter (the diameter of
>the Apollo command module)?  

Oh, I see!  You're thinking human payload!  Ick!  Railguns won't work;
coilguns might but that's sorta stupid.  The whole problem with the space
program, IMHO, is concentrating on manned flights.  It's a stupid, silly,
expensive idea.  Until we get a hand on our ecosystem and get our resources
together, we should concentrate on unmanned stuff.  (Jeez ... imagine,
10,000 G's.  It'd certainly be a fun ride .... not!)

>A.Lizard, stop insulting people you don't know (such as everyone
>at McDonnell-Douglas).  There are often really good engineering
>reasons behind the way things are done.  The laws of physics
>weren't established as a personal affront to you, which is the
>way you've come off in this discussion.  Howzabout this?  Next
>time you want to pop off at someone for not building something
>the way you think it ought to be built, take a look in a high-
>school physics text and at least come up with a rough idea of
>what's involved.

No, I think A.Lizard is right.  I never got the impression that either he
or the people he talked to were talking about human payloads.  The real
use of railguns and coilguns (I tend to favor the latter) are in payloads
like satellites, automated landers, even raw ore and minerals (thus the
idea of shooting off of the moon towards Earth).
And a lot of traditionalist rocket jocks are very much against it.  But
not all.  I remember hearing a NASA physicist talk about railguns and
coilguns, and he said that it's feasible NOW, just that A) non-manned
space activity is nowhere near as glamorous, B) a lot of people have too
much money in existing programs, and C) we still need better high-temp
superconductors.

>And laugh more.  You really ought to laugh more!

Humans in railguns ... hee hee!  The whole idea of very very flat people
comes to mind!

>				- - Steve



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