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Date: Sat, 10 Apr 93 05:25:08
From: Space Digest maintainer <digests@isu.isunet.edu>
Reply-To: Space-request@isu.isunet.edu
Subject: Space Digest V16 #448
To: Space Digest Readers
Precedence: bulk
Space Digest Sat, 10 Apr 93 Volume 16 : Issue 448
Today's Topics:
Biosphere II
Budget Astronaut (was: Idle Question)
Question- Why is SSTO Single Stage
Shuttle Status for 04/09/94 (Forwarded)
Vulcan? (No, not the guy with the ears!)
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----------------------------------------------------------------------
Date: 10 Apr 1993 08:07:21 GMT
From: George William Herbert <gwh@soda.berkeley.edu>
Subject: Biosphere II
Newsgroups: sci.space
I don't think that Biosphere II is bad science, and here's why.
Science is to some extent about developing accurate models of the real world.
In science done about ecosystems, particularly closed ones,
there has been a strong tendency to concentrate on trivially
simple systems and study the hell out of them, trying to pin
down some little cycle to great detail.
Bio II said "No, wait, let's take the big picture and see how accurate
our big picture models are..." and went out and did it. No, it's not
studying the little cycles as well as the smaller experiments can;
it _can't_, it's got too many variables. That's not the point,
never was, and really doesn't have to be. Bio II is pointing out
holes in higher level theories and trying to point new directions
for lower-level research.
Thinking it's bad science is narrow-minded. It's not incredibly good
science either; it's got some holes in it, and a whole lot of variables
that they really should have kept better track of. However, it's providing
_the_ comparative model for complex close ecosystems analysis.
Nobody's done it before, so people tried to put them together from
the smaller cycle models and found that it doesn't just work that way.
Eventually, when we know everything, we'll be able to do that.
But until we do, stepping back and getting a good overall look
at the situation is not bad science.
-george william herbert
gwh@ocf.berkeley.edu
------------------------------
Date: Sat, 10 Apr 1993 06:03:36 GMT
From: Henry Spencer <henry@zoo.toronto.edu>
Subject: Budget Astronaut (was: Idle Question)
Newsgroups: sci.space
In article <1q5lr6$j7j@agate.berkeley.edu> gwh@soda.berkeley.edu (George William Herbert) writes:
>>... which puts Scout out of the running unless
>>you can beat George's weight numbers substantially. (Probably possible,
>>but maybe only by fairly radical methods.)
>
>I'd estimate from other work of mine that a 275-300 kilo vehicle could
>be made that would _safely_ sustain life for a few hours and return
>the crewman to the surface...
>...A person with a heatshield, a re-entry solid rocket,
>and a space suit might fit on a scout, but it would be way unsafe
>and there would be no systems redundancy. I wouldn't recommend it.
The ultimate version of this eliminates the heatshield. Really, it can
be done, at least on paper -- you use a specially-designed parachute to
increase the surface area for deceleration, and wear a heat-resistant
space suit (some of the NASA suit designs have actually been very good
thermal insulation, good up to remarkably high temperatures). I expect
you'd have to switch to a more conventional parachute for landing. The
idea was studied a bit, some years ago.
However, I don't know why you'd *want* to use Scout rather than Pegasus,
especially when you can be rather more comfortable, and significantly
safer, with the extra mass to help.
--
All work is one man's work. | Henry Spencer @ U of Toronto Zoology
- Kipling | henry@zoo.toronto.edu utzoo!henry
------------------------------
Date: 10 Apr 1993 07:53:01 GMT
From: George William Herbert <gwh@soda.berkeley.edu>
Subject: Question- Why is SSTO Single Stage
Newsgroups: sci.space
In article <1993Apr9.150945.7884@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes:
>Shooting for minimum operational cost doesn't necessarily mean throwing
>away all hint of performance, [...]
No, but aerospace engineers tend to draw a blank when presented with the
opportunity to lower system cost by making it bigger but cheaper per lb.
You'd be amazed what you can get away with if you intentionally design
a vehicle for lower performance and with higher margins; I can give you
vehicles whose construction & launch cost (ignoring development and profits)
is about a dollar a pound. They have initial-payload ratios of 250 to 1
as opposed to 60 to 100 to 1 for current launch vehicles, but they also
are a hell of a lot cheaper.
[Or hope to be able to do so, sometime soon...
at least I can show you how now 8-) ]
-george
------------------------------
Date: Sat, 10 Apr 1993 01:52:22 GMT
From: "Ralph A.M.J. Wijers" <rw@ourania.Princeton.EDU>
Subject: Shuttle Status for 04/09/94 (Forwarded)
Newsgroups: sci.space
Question: for those of us who want to get something useful
out of reading newsgroups, but have other things to do, it
would be quite useful if:
1. People don't post messages in more than one of the
groups sci.space
sci.space.news
sci.astro
Don't be afraid to choose, I'm sure most people who might
be interested in subjects that could be in any of these
groups would subscribe to all three.
2. If people would take some care not to forward the same thing
umpteen times to these newsgroups. (I got the shuttle status
to which this is a 'reply' 4 or 5 times in sci.space alone).
Sorry for the grumpy tone, but I thought it needed to be said.
Ralph Wijers
------------------------------
Date: Sat, 10 Apr 1993 05:55:50 GMT
From: Henry Spencer <henry@zoo.toronto.edu>
Subject: Vulcan? (No, not the guy with the ears!)
Newsgroups: sci.space
In article <stephens.734028064@ngis> stephens@geod.emr.ca (Dave Stephenson) writes:
>... Vulcan was supposed to have been
>observed by a somewhat dubious 'gentleman' astronomer who kept
>his notes on a plank of wood, and used plane as an eraser.
This was at a time when many astronomers were "gentleman" astronomers;
the only thing that was unusual about Lescarbault was that he persisted
in his hobby despite not being wealthy. Leverrier himself visited
Lescarbault and concluded that he was no mathematician but appeared to
be an honest man and a competent observer; it was through Leverrier's
recommendation that he was awarded a medal by Napoleon III in 1860.
Unfortunately, with one exception, later attempts to locate the object
Lescarbault saw were fruitless. The (possible) exception was that
James Craig Watson, at U of Michigan, and Lewis Swift, observing from
Pike's Peak, both reported near-Sun objects (Watson thought one showed
a disk) during the solar eclipse of 1878.
It's reasonably plausible that all three men saw asteroids with eccentric
orbits near perihelion.
Reference: Willy Ley's "Watchers of the Skies" has a good discussion
of the hunt for Vulcan.
--
All work is one man's work. | Henry Spencer @ U of Toronto Zoology
- Kipling | henry@zoo.toronto.edu utzoo!henry
------------------------------
End of Space Digest Volume 16 : Issue 448
------------------------------