Message-ID: <gZMEYwe00VcJMdMU4f@andrew.cmu.edu>
Reply-To: space+@Andrew.CMU.EDU
From: space-request+@Andrew.CMU.EDU
To: space+@Andrew.CMU.EDU
Date: Wed, 15 Nov 89 01:59:11 -0500 (EST)
Subject: SPACE Digest V10 #250

SPACE Digest                                     Volume 10 : Issue 250

Today's Topics:
		      Re: Hubble Space Telescope
		    Re: Moon Colonies / Ant Tanks
	       Re: Population pressure to move to space
	   Re: NASA Headline News for 11/14/89 (Forwarded)
		 Re: Manned Jupiter Mission (was Re:
----------------------------------------------------------------------

Date: 14 Nov 89 17:23:41 GMT
From: agate!sag4.ssl.berkeley.edu!daveray@ucbvax.Berkeley.EDU  (David Ray)
Subject: Re: Hubble Space Telescope

In article <2262@hudson.acc.virginia.edu>,
    gsh7w@astsun9.astro.Virginia.EDU (Greg S. Hennessy) writes:
>In article <590B0C11140C02E7-MTABWIDENER*DXANDY@widener> DXANDY@WIDENER.BITNET writes:
>#
>#  I recall reading somewhere that the Hubble Space Telescope would be able
>#to resolve continents on planets orbiting distant stars.  Is this a piece of
>#fanciful reporting, as it would seem, or is there actually some basis in
>#truth?
>
>The resolution of HST is [roughly] 20 milliarcseconds. Let us consider
>Alpha centuri. It is about 1.3 parsecs away, this 1 arcsecond will be
>1.3 AU or about 130 million miles. 20 mas will be about 26 million
>miles. This is about 100 times the earth moon distance. I would
>consider it rather awful reporting myself.

   While the optical resolution is 20 milliarcseconds, spacecraft
attitude jitter may increase this figure (reduce resolution) for
effective mapping; There is question as to how accurate the
data algorithms can correct for attitude jitter.
As a result is it even less likely that planets could be "seen" directly.
   My understanding is that Hubble will see
positional fluctuations/pertubations in nearby stars which are
assumed to be caused by planets; The planets will therefore be
inferred to be "detected" from the star's positional fluctuations.
   One proposal I saw for the Hubble focal plane was a "planet sensor"
which was made by physically blocking out the light of a targeted
star VERY close (angularly) to the star's perimeter; the detector
would then look for a point of light just outside the star and
many orders of magnitude fainter. I don't believe this instrument
made it onto the Hubble, though. I speculate that it probably would
not have worked because of the attitude jitter problem. If the
star came into the field of view of the sensor while looking for a
much fainter object the image would be wiped out and possibly damage
the detector.

   Disclaimer: All this is off the top of my head from scattered information
I have collected in the last couple years. Please correct anything
posted here for which you have first-hand knowledge. I am interested
in these issues but I do not work for HST.

-Dave

------------------------------

Date: 14 Nov 89 07:39:26 GMT
From: rochester!yamauchi@louie.udel.edu  (Brian Yamauchi)
Subject: Re: Moon Colonies / Ant Tanks

In article <14913@bfmny0.UU.NET> tneff@bfmny0.UU.NET (Tom Neff) writes:
>Olympic athletes, like Henry's odd claustrophiles, prove that some
>people choose extreme lifestyles and prosper.  But what about the
>kids, is the question!  If you tried to force your toddler to
>be a shot put maniac they'd nail you for child abuse; same thing
>if you never let him leave the basement.  You cannot expect children
>to share their parents' maladjustments.

This ignores both the adaptability of the human species and the fact
that what is maladjustment in one environment is often adaptive
behavior in another.

Anyone who would want to live in a forest, hunting and gathering all
of his food, and living without any modern technology is seriously
maladjusted for modern society.  However, a few centuries ago, this
would have been considered adaptive behavior for those living on this
continent.

Comparing a colony to a basement is absurd, at least if you're talking
about kids.  True, the early scientific bases will be spartan, but by
the time anyone is thinking of taking children or families into space
on a permanent basis, the colonies would have to be more on the order
of apartment complexes.

We're not talking about locking a kid in a damp, dingy cellar.  Assume
for a moment, that space colonies will have similar population
densities to a high-rise apartment, an office building, or a shopping
mall.  A large proportion of the population (including kids) spends a
large portion of their lives in these environments without considering
themselves abused or deprived.

It seems unwarranted to assume that because a lot of people like to
spend a portion of their day outside that this is a need genetically
hardwired into the human mind.  A lot of people like to spend a
portion of their day watching television.  Does this mean that a need
for television is an integral part of the human psyche? (I would also
guess that a fair portion of those kids you're concerned about would
rather give up their time outdoors than their television.)

The point is that given reasonably comfortable accommodations, I can't
see any reason why living in space should be psychologically
unbearable for most individuals -- there will be exceptions, of course
(astrophobes, perhaps?).  After a while, I'm sure that many spacers
will start to wonder how people on Earth can stand the heavy gravity
and how they can bear to miss seeing the blue globe in their skies.

_______________________________________________________________________________

Brian Yamauchi				University of Rochester
yamauchi@cs.rochester.edu		Computer Science Department
_______________________________________________________________________________

------------------------------

Date: Tue, 14 Nov 89 08:15:13 PST
From: mordor!lll-tis!ames!ucsd!pnet01.cts.com!jim@angband.s1.gov (Jim Bowery)
To: crash!space@angband.s1.gov
Subject: Re: Population pressure to move to space

Paul F. Dietz writes:
>Overpopulation is a myth.  Current demographic projections have world
>population growth stopping at about 10 billion people around 2100.

I've seen projections that put the carrying capacity of Earth, in
a steady state technological society, at 200 million humans.  I don't
believe every projection I've read but I find this at least as believable
(given my lack of faith technology's ability to economically replace 
critical nonrenewables) as the projection that our population will less 
than double in the next century.  There are other limiting factors, such
as the probability, increasing every year, that someone (including
evolution, eg AIDS or just plain stupidity, eg ozone depletion) will come 
up with a way of making the planet uninhabitable for human beings.
Then there are the "minor inconveniences" of biological and cultural
impoverishment as development, communication and transportation eliminates
habitats supporting fragile diversity.

I'm not even sure we can replace those nonrenewables by looking around
our solar system, given the unique geological processes that created our
critical ores and the rather large, thermodynamically inherent,
inefficiencies limiting our ability to recover materials from "country 
rock" or other low-grade muck, even given a significant fraction of
the sun's power.

In short, the consequences of an Earth-bound technological civilization
at a level of 10 billion humans (even 5 billion) are profound enough
to justify timely investigation of our solar system as a new habitat 
for that civilization.  We do NOT "have the technology" to just go
"do it".  The myth that we do is a very negative legacy of G. K. O'Neill's
book "The High Frontier".  Large scale development now would make it 
impossible to pursue economically viable development based on future 
research results by depleting our resources, economic, material and
spiritual.  Small scale development now, in the form of "infrastructure 
projects" such as Space Station is gutting our ability to provide those 
future research results in a timely manner.
---------------------------------------------------------------------------
Jim Bowery      PHONE: 619/295-8868     BE A SPACE ACTIVIST
PO Box 1981            GET OFF THE NET AND SET UP AN APPOINTMENT WITH YOUR
La Jolla, CA 92038                         CONGRESSMAN!
---------------------------------------------------------------------------
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INET: jim@pnet01.cts.com

------------------------------

Date: 15 Nov 89 04:02:04 GMT
From: zephyr.ens.tek.com!wrgate!mrloog!dant@uunet.uu.net  (Dan Tilque)
Subject: Re: NASA Headline News for 11/14/89 (Forwarded)


 yee@trident.arc.nasa.gov (Peter E. Yee) writes:
>
>The Washington based publication "Space News" reports that 
>scientists from Lawrence Livermore National Laboratory have 
>proposed that NASA build an inflatable space station, moon base 
>and deep space probe, in an attempt to cut the cost of sending 
>U.S. astronauts to Mars.  "Space News" says the Livermore plan 
>calls for the development of a large, inexpensive unmanned 
>rocket...and errecting a series of inflatable space structures 
>whose walls would be reinforced by kevlar, a strong, lightweight 
>fiber.  The publication says NASA is completing an assessment of 
>the Livermore plan.

How many want to bet that this idea will be killed as quietly as
possible.  Why?  Because it would mean the death of Space Station
Freedom.  A lot of money and effort has been invested in Freedom and
thus it has a large and growing constituency.  This new idea, despite
its advantages, will have a few flaws (almost all new ideas have some
flaws) and these will be used by that constituency to kill it.  (The
fact that it comes from outside the Space Station project is, of
course, its major flaw.)

This is called either human nature, politics or bureaucracy, depending
on your point of view.

---
Dan Tilque	--	dant@mrloog.WR.TEK.COM

When it comes to NASA and space contractors, there's no such thing as too
much cynicism.

------------------------------

Date: 13 Nov 89 22:17:36 GMT
From: littlei!nosun!snidely@uunet.uu.net  (David Schneider)
Subject: Re: Manned Jupiter Mission (was Re:

In article <2241@frog.UUCP> john@frog.UUCP (John Woods) writes:
>True, but the engineers noodling around with designs actually know about this.
>...a standard vehicle with a small, well-shielded chamber inside.  When they
>detect a solar flare, everyone piles into the shielded chamber and rides
>it out.  (The light arrives well before the particles...)
>-- 
>John Woods, Charles River Data Systems, Framingham MA 508-626-1101

Sounds like the engineers are remembering Heinlein's space liner
from *Podkayne of Mars*.  This man was not only the Naval Academy's
top fencer, but good with engineering, too.

But in case you're worried about
his being a reliable prophet, consider *his* Galileo spacecraft
(a rocket ship described in, you guessed it, *Rocketship Galileo*):
built by a dropout scientist and his teenage crew,
using the shell of a ballistic transport and a nuclear blowdown
engine with zinc propellant, capable of SSTL (single-stage-to-Luna).

					Dave Schneider
					Monday, Nov 13

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End of SPACE Digest V10 #250
*******************