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Subject: SPACE Digest V13 #613

SPACE Digest                                     Volume 13 : Issue 613

Today's Topics:
               Re: Saturn V and the ALS
               Gravity vs. Mass
         Re: New Subject--Solar Collectors/Antimatter
        Re: Hypersonics ... paritcularly Hotol
                Re: lifeboats
           Re: Keck (was Re: Privatization)
             Re: 2001 and "The Endeavor"
               Re: Scale models
           Grinding Axes and Picking Bones

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Date: 21 May 91 08:07:43 GMT
From: agate!maelstrom.Berkeley.EDU![e-mail]  (Frank Crary)
Subject: Re: Saturn V and the ALS

In article <[e-mail]> [e-mail] (Allen W. Sherzer) writes:
>If wisely selected I don't see any problems. We would set up a LLNL
>inflatable station and a series of free-flyers. The main station would
>be used to house crew, perform life sciences work, house a 0G dry dock
>and some microgravity (so experimenters can see their experiment in
>real time and make changes). Outside would be a number of free flyers
>for microgravity, manufacturing, and a fuel depot. You would need to
>insure that everybody is compatable but it wold reduce costs to share
>the basic facilities.

Insureing that everybody is compatable is exactly the problem. For example,
in the Freedom design, someone (A congressional administrative assistant with
lost of pull, if I rememble correctly) said "There is not way you are going
to put a centrafuge into the microgravity lab. It will mess up the materials
processing experiments. (Which are what _I_ think is important.)" Since
there was no clear directive as to the purpose of Freedom, those designing
the lab could not say either "Too bad, this is a zero-g biology lab. Dump
the materials processing stuff that can't take the vibrations" or "Ok, since
this is a materials processing lab, we'll dump the zero-g bio people's
centrafuge." As a result, they had to spend a lot of time and effort to
design and place a centrafuge that would be usefull to the zero-g bio people,
but would not compromise the materials processing experiments. Is this really
the sort of can of worms you want to open?

                    Frank Crary
                    UC Berkeley

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Date: 21 May 91 05:31:05 GMT
From: swrinde!zaphod.mps.ohio-state.edu!samsung!umich!ox.com!math.fu-berlin.de!msi.umn.edu!cs.umn.edu!ub.d.umn.edu![e-mail]  (Isildur)
Subject: Gravity vs. Mass

I was having a debate with one of my friends over this one... You somehow
dug a hole clean through the earth in a diameter through the core and it was
completely insulated from the heat changes running through the planet.  When
you climbed into the tunnel (fall into the the tunnel...) and reach the
center of the planet, would your weight be incredibly multiplied because of
your new relative location to the center of the earth (using the
mass/gravitational constant formula) or would you have zero-weight because
you were surrounded by virtually identical mass (and also assuming that the
tunnel closes up outside your immediate location)?

------------------------------------------------------------------------------
    [e-mail]        |    "So many questions, so little
                    |     time!"
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Date: 15 May 91 16:54:49 GMT
From: elroy.jpl.nasa.gov!swrinde!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!pitt!nss![e-mail]  (Paul Blase)
Subject: Re: New Subject--Solar Collectors/Antimatter

to: [e-mail] (Mark Gellis)


 MG> I have a question or two regarding possible future applications
 MG> of solar power.  Robert Forward suggests that it is possible to
 MG> produce antimatter with a reasonable degree of efficiency.  His
 MG> design, however, calls for a lot of power.

The key is to get the power where it it cheap (a solar power satellite
or a terrestrial power plant) and use the antimatter where it is needed
(in space-propulsion applications where you need speed and can't afford a
 large fuel mass).

 MG> Now, since the use he suggests for antimatter is rocket fuel

Strictly speaking: the matter/antimatter annihilation is
used to heat the reaction mass.

 MG> (his argument, which
 MG> I accept, is that it is so expensive that fusion and solar are
 MG> really much better for most other power requirements), it makes
 MG> sense to bring in other space-related technologies.  If you
 MG> have a space-based economy a few hundred years down the line,
 MG> you need a LOT of antimatter if you want people zipping around
 MG> the solar system.....

Important note: the use of antimatter is NOT that it deliveres 'more power',
but that it packages a LOT of power into a small space; it is particularly
useful for missions such as solar-impact probes and orbit reversing
(leaving orbit and catching up with a target going the other direction)
that would not be possible if you had to accelerate a large fuel load
in addition to the payload.

 MG> My question regards the efficiency of solar collectors.  Now,
 MG> obviously, technology will change and improve during the next
 MG> few centuries, but based on what we know today about such solar
 MG> power cells...

 MG>    1) Given a solar cell that will produce 10 kilowatts in
 MG>  Earth orbit, would the same cell (i.e., the same mass of
 MG>  finished product) produce more power if it was moved to Venus
 MG>  orbit, where it would be getting more than twice as much
 MG>  energy from sunlight?  (If power is the wrong word, I
 MG>  apologize; you know what I mean, though.)  Will it produce 20+
 MG>  kilowatts now?  Do the cells have a limit on how much
 MG>  electricity they will produce, or will they just keep giving
 MG>  you more power if you increase the solar energy per square
 MG>  meter?

There is a limit, but in general photovoltaic cells operate most efficiently
at very high light levels.  This is why many new solar-cell designs use
concentrators (mirrors) to increase the light flux at the cell.  The closer
you are to the sun, obviously, the smaller a system you need for a given
amount of light on your cell.

 MG>    2) If you can get more energy from solar cells by moving
 MG>  them closer to a star, what is the limit?

When your cell melts, or other thermal effects start to cut into the
efficiency.


Don't forget that there is another way of producing electricity from
sunlight: dynamic power, aka a steam turbine.   I think that it is a
toss up as to which would be cheaper right now.

--- via Silver Xpress V2.26 [NR]
--
Paul Blase - via FidoNet node 1:129/104
UUCP: ...!pitt!nss!Paul.Blase
INTERNET: [e-mail]

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Date: 21 May 91 18:03:35 GMT
From: agate!spool.mu.edu!sdd.hp.com!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Hypersonics ... paritcularly Hotol

I wrote:
>There was talk about a Hotol derivative using conventional rockets launched
>from the back of an Antonov Mriya.  This would have avoided the problematic
>engine technology proposed for the original.  Favorable noises were being
>made about it, but I have heard nothing recently.

Rumor (via email) hath it that aerodynamic problems killed the idea, but
I have no details.
--
And the bean-counter replied,           | Henry Spencer @ U of Toronto Zoology
"beans are more important".             |  [e-mail]  utzoo!henry

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Date: 21 May 91 18:20:00 GMT
From: agate!spool.mu.edu!think.com!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: lifeboats

In article <[e-mail]> [e-mail] (George William Herbert) writes:
>>The one SM function that would have to be provided by new hardware would
>>be retrofire.  The obvious method is a set of small solid motors a la Gemini.
>
>You're forgetting something... all the orbital maneuvering (reaction control
>system etc) was on the SM if I remember correctly...

Nope, not correct.  The CM had its own RCS for reentry.  If you want to do
orbital maneuvering -- it's not clear why -- then yes, you'd have to add
something for that.  Take the RCS thruster "quads" from the SM, which were
self-contained (each quad had its own little tank set just underneath it)
and put them on whatever adapter you're using to hold the solid retros.

>... I'm not sure how happy the
>astronauts would be about dropping hydrazine in their capsule for RCS
>purposes...

There were in fact a couple of incidents in which RCS propellant venting
after parachute deployment contaminated the cabin air and made some of
the astronauts sick.  I think they sorted this out by some procedural
revisions.
--
And the bean-counter replied,           | Henry Spencer @ U of Toronto Zoology
"beans are more important".             |  [e-mail]  utzoo!henry

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

Date: 22 May 91 04:21:51 GMT
From: att!pacbell.com!mips!samsung!dali.cs.montana.edu!ogicse!sequent!muncher.sequent.com![e-mail]
Subject: Re: Keck (was Re: Privatization)

In article <[e-mail]> [e-mail] (Paul Dietz) writes:

>[scopes vs. probes]
>Sure, there are
>questions that can only be answered on-site, but the questions the
>telescopes are trying to address (the fate and nature of the universe
>as a whole) seem more fundamental.

The "fundamentalism" of the science is not the fundmental issue here,
if you'll pardon me.  :-)

Exploration -- including exploration through telescopes -- can be done
for reasons ranging from fundamental science to a totally industry-oriented
project.  Oil exploration is a contemporary example of the latter.

I won't get into the "pure" vs. "applied" issue here.  The point is that
practical exploration may follow a similar technological pattern as
fundamental exploration.  One applied problem, for example, is
increasing the number of known earth-crossing asteroids, in order
to find those with the minimum impulse delta-V to earth orbit.
For this problem, an array of telescopes with CCD's can be more
cost-effective than onsite probes.  Other problems, both scientific
and applied, can be better solved by probes.  There is no "fundamental"
(there's that word again :-) reason why applied explorers would favor
on-site inspection any more than the pure science explorers.



--
Nick Szabo                [e-mail]
"If you understand something the first time you see it, you probably
knew it already.  The more bewildered you are, the more successful
the mission was." -- Ed Stone, Voyager space explorer

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Date: 22 May 91 15:43:04 GMT
From: sdd.hp.com!wuarchive!news.uu.net!mcsun!ukc!icdoc!syma![e-mail]  (Nick Watkins)
Subject: Re: 2001 and "The Endeavor"

From article <[e-mail]>, by [e-mail] (John A. Weeks III):
> something worth checking out.  According to the book, even when NASA had
> a clear cut goal to chase, they still wandered around aimlessly.  The more
> things change, the more things stay the same....
Not sure if NASA exists in 2001/2010 books, Heywood Floyd works for an outfit
called the NCA, National Commission on Astronautics (?).

Nick
--
Dr Nick Watkins, Space Plasma Physics, Univ. of Sussex, Brighton BN1 9QH, UK
JANET: [e-mail]        BITNET: [e-mail]

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Date: 22 May 91 15:32:24 GMT
From: usc!elroy.jpl.nasa.gov!sdd.hp.com!wuarchive!news.uu.net!mcsun!ukc!icdoc!syma![e-mail]  (Nick Watkins)
Subject: Re: Scale models

From article <[e-mail]>, by [e-mail] (Gaston Groisman):
> I am wondering about the existance of scale models of the Hubble Space
> Telescope and the Voyager space craft.  Has anybody seen these in any
> hobby shop?
No, but an advert in recent copy of Fine Scale Modeller announces the
Voyager 1/35 scale kit from :


Lunar Models
5120 Grisham
Rowlett
TX 75088
USA

tel [phone]

or in US 1 800 662 4984.

Please post if you find out more

Nick
--
Dr Nick Watkins, Space Plasma Physics, Univ. of Sussex, Brighton BN1 9QH, UK
JANET: [e-mail]        BITNET: [e-mail]

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Date: Wed, 22 May 91 20:34:20 PDT
From: [e-mail] (Jim Bowery)
To: crash![e-mail]
Subject: Grinding Axes and Picking Bones

Someone asked me what axe I'm grinding.  Maybe I should come clean:

I was born and raised in a small Iowa town.  You know... we didn't lock
our doors at night, etc.  I believed the things they taught me in civics
class about American values.  When I confronted the cynical "realpolitick"
that has consumed our society and its future from the top down in the
form of NASA, I decided maybe I should exercise my right of free
speech, right of petition, etc.  Despite the inconvenience this may cause
to some, I'm not going to apologize for being rather insistent that
traditional American values be followed in the one place they count the
most:  Opening our next frontier.

I consider this important enough to take action on because I really do
think space is our destiny and best hope of survival, but I don't think
it is "inevitable" that we will make it.  We're clearly in crisis mode.

How does this relate to Space Station Fred?

Republicans who support the space station program fit the definition
of "conservative" as it is used in the Soviet Union.  They want to
"conserve" the bureaucratic structures that benefit their friends by
suppressing freedom with doublespeak like "Freedom".  Enterprises such as
Spacehab, Space Industries Inc. and other nascent microgravity service
companies were beaten into submission by NASA and then captured by former
"leaders" of Space Station program prime contractor McDonnell Douglas
such as James Rose and Jake Jacobson as well as the NASA administrator
that initiated Fred as an "all things to all people in all Congressional
districts" porkbarrel juggarnaut:  James Beggs.

For a wonderful, heart-warming history of the way these parasites were
so "helpful" to the SII/ISF and Spacehab, I refer you to current issue
of the "Air and Space" magazine from that libelous radical fringe group:
the Smithsonian.  I have my own experiences with employees of McDonnell
Douglas who have engaged in similar "promotional" activities on behalf
of Fred.

This kind of bureaucratic suppression of free enterprise is all too
familiar to people who are trying to create free markets in eastern
Europe and USSR.  The problem is even worse with NASA because of all
the doublespeak/doublethink that started with the program under
Mr. Free Enterprise himself, Ronald Wilson Reagan, in that banner
year for space:  1984.

Fred isn't mere socialism, where the government has some ownership
but little control, as in Sweeden.  The space station is hard-core
communism with burueacratic ownership and management, shielded by a
thin veil of aerospace "contractors" who are little more than extensions
of the government agencies that employ them.

In particular, the following, Republican members of the VA HUD and
Independent Agencies subcommittee of the Senate Appropriations committee
have demonstrated, by their support of programs like Fred, that they are
practicing de facto communists despite their party affiliation:

Cosmonaut Jake Garn     202/224-5444
Alfonse D'Amatoff       202/224-6542
Donsky Nickles          202/224-5754
Phil Grammivich         202/224-2934
Christopher "Vlad" Bond 202/224-5721

If anyone else still believes traditional American values are the
best way of opening frontiers like the West and space, you might
give these guys a call and ask them when they would like a copy
of "Das Kapital" as a guide-book to the correct management of
monolothic government bureaucracies like NASA.  They clearly aren't
as competent at being a central party member as the guys in the USSR
given the relative performances of Mir and Fred.

Maybe we should do a foreign exchange:  NPO Engergia managers come
here to teach us how to run a communist space program like NASA,
in exchange for some of our commodities brokerage experts.

On the other hand, maybe we should just "Axe" Fred.
-----------------------------------------------------------------------------
Jim Bowery      619/295-3164               The Coalition for
PO Box 1981                                   Science and
La Jolla, CA 92038                             Commerce
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End of SPACE Digest V13 #613
*******************