Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V16_0/V16NO029.TXT

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Date: Sat,  9 Jan 93 05:15:02
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #029
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Space Digest                Sat,  9 Jan 93       Volume 16 : Issue 029

Today's Topics:
                  *** BUSSARD RAMSCOOP *** (2 msgs)
        Cheap Mars Rocks (was Re: Moon Dust For Sale) (4 msgs)
               Dr. Beter AUDIO LETTER archive location
      Let's be more specific (was: Stupid Shut Cost arguements)
                   Mars Observer Update - 01/08/93
         Small vs. Large Rovers (was Re: How to Explore Mars)
                           testing rockets

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

Date: Sat, 9 Jan 1993 04:39:32 GMT
From: Dave Michelson <[e-mail]>
Subject: *** BUSSARD RAMSCOOP ***
Newsgroups: sci.space

Several postings ago, I mentioned the possibility of quark-catalyzed fusion.
As promised (and requested) here are some additional details...

I smilied [:)] my original reference to quark catalyzed fusion since it
doesn't really apply to the problem of catalyzing fusion in a ramscoop :(
but it remains an interesting possibility for power generation here on earth
*if* free quarks can ever be isolated.

Quark catalyzed fusion is similar in concept to muon catalyzed fusion
with a difference - quarks don't decay.

From F. Close, ``The quark structure of matter,'' in The New Physics,
P. Davies, Ed., Cambridge: Cambridge Univ. Press, 1989, p. 422:

"Some of the practical details have already been evaluated and are as follows:

"A pair of antiquarks with charge -4/3 come to rest in hydrogen or deuterium at
a pressure of 2000 psi (1.4 x 10^7 N/m^2).  They capture a molecule and form
a system with charge -1/3.  The resulting `quark-molecule' is very excited.
It takes a short time to settle down, `de-excite', and in this time it captures
another nucleus, of charge +1, and fuses.  A quark is released to go on and
do the job again.  The process can be summarized by the sequence,

         Q + [D(pn) + D(pn)] -> [3H(pnn) + p] + (energy) + Q,

where Q = quark, D = deuteron, and 3H = tritium.

"The new quark moves on to the next nucleus and can initiate further fusion.
The reaction rate is one per second at 2000 psi pressure.  For deuterium,
this releases 3.65 MeV energy per fusion.  A few grams of quarks could
catalyze fusion and generate 10% of the total USA energy consumption!

"There appears to be only one weak link in the whole enterprise: no one has
yet found isolated free quarks!"

Various people have found evidence which suggests that free quarks exist
including Brian McCusker (cloud chamber photo in 1968) and William Fairbank
at Stanford (a variation on Millikan's experiment using niobium coated
tungsten balls).

At present, theorists conjecture that quarks are confined in colourless
clusters (hadrons) but this has not been *proved*.  It seems possible that
free quarks may exist.

If nothing else, it is interesting to contemplate the possible consequences
of free quarks...

--
Dave Michelson
[e-mail]

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

Date: 9 Jan 93 06:57:15 GMT
From: Henry Spencer <[e-mail]>
Subject: *** BUSSARD RAMSCOOP ***
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Dave Michelson) writes:
>Several postings ago, I mentioned the possibility of quark-catalyzed fusion.
>As promised (and requested) here are some additional details...

Quark-catalyzed fusion is for wimps. :-)

The modern quantum version of a magnetic monopole is much more interesting
in this regard than loose quarks.  It's a very strange particle, immensely
massive by particle-physics standards, and tucked away in its center is a
small region of space with exceedingly peculiar properties.  Two small
problems exist:  we've never seen one, and the effective cross-section of
that central region is very uncertain (and there is some reason to think
it's pretty small).  But if they exist, or can be made, and if that
cross-section is substantial...

A wandering magnetic monopole brushes past a proton.  Actually, more or
less through it -- the monopole is many orders of magnitude more massive
(I said it was heavy!) and protons aren't solid.  As the monopole goes
through, one of the quarks in the proton wanders into that funny region
of space... and comes out as an antiquark.

An instant later, it meets one of the other quarks in the proton, and
the proton explodes.

When the dust has cleared, all that remains is a positron, some gamma
rays, and maybe a neutrino or two.  The monopole is unaffected, so
heavy that even its trajectory is barely altered by the fireworks.
You read it right:  the monopole catalyzes proton decay, essentially
doing matter->energy conversion without that annoying requirement for
an antiproton supply.

The problem with all this is that there is moderately convincing evidence
that either monopoles are pretty rare in nature, or that cross-section is
very small.  For one thing, if a monopole with the properties we want
passed through something like the Kamiokande neutrino/proton-decay
experiment -- the kilometer or two of rock over top wouldn't even slow
it down -- the event would be seared permanently into the memories of
the detectors.  That hasn't happened.  Other lines of evidence concur.
And all of this, of course, assumes that the theorists haven't goofed.

Still... THAT's a Bussard ramjet powerplant for you!
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: 9 Jan 93 04:10:13 GMT
From: Anthony Datri <[e-mail]>
Subject: Cheap Mars Rocks (was Re: Moon Dust For Sale)
Newsgroups: sci.space,sci.astro,alt.sci.planetary

>To get the Mars rock I'm talking of down to earth didn't cost a single cent,
>by the way. The 18kg SNC-meteorit simply fell out of the sky in October, 1962
>near Zagami rock in Nigeria.

I must admit some skepticism wrt meteorites that are claimed to have been
ejected from Luna and Mars.
--

======================================================================8--<

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

Date: 9 Jan 93 06:33:47 GMT
From: Henry Spencer <[e-mail]>
Subject: Cheap Mars Rocks (was Re: Moon Dust For Sale)
Newsgroups: sci.space,sci.astro,alt.sci.planetary

In article <[e-mail]> [e-mail] (Anthony Datri) writes:
>I must admit some skepticism wrt meteorites that are claimed to have been
>ejected from Luna and Mars.

The evidence for the lunar meteorites is pretty convincing.  The Mars ones
aren't as solidly established, but they're getting there.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: 9 Jan 1993 08:17 UT
From: Ron Baalke <[e-mail]>
Subject: Cheap Mars Rocks (was Re: Moon Dust For Sale)
Newsgroups: sci.space,sci.astro,alt.sci.planetary

In article <[e-mail]>, <[e-mail]> writes...
>Why buy 1gramm moondust for about $4000.- (or 1 pound for $2'000'000)
>when I bought 4g Mars rock for $350.- two years ago???
>

The going rate for the Zagami meteorite is still about $100 per gram and
that is the lowest of all the SNC meteorites.  The Nahkla meteorite is going
for something like $200 to $300 per gram.  The price on the Chassigny is
sky high because there are so few pieces that have left France.  The
two Chassigny pieces I've seen were only 8g and 13g, but were selling for
$24,000 and $39,000, respectively.

>Taking all the known SNC meteorites known, there are hardly more than 100pounds
>of mars rock available. Thus, $100,000 for a two inch tape of moondust is quite
>a high price|| I think I'll wait until a *large* lunar meteorite drops down
>somwhere...

The moon dust hasn't been sold yet, and I think it will go for well under
the $100,000.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Choose a job you love, and
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | you'll never have to work
|_____|/  |_|/       |_____|/                     | a day in your life.

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

Date: 9 Jan 93 08:30:52 GMT
From: Ron Baalke <[e-mail]>
Subject: Cheap Mars Rocks (was Re: Moon Dust For Sale)
Newsgroups: sci.space,sci.astro,alt.sci.planetary

In article <[e-mail]>, [e-mail] (Anthony Datri) writes...
>
>>To get the Mars rock I'm talking of down to earth didn't cost a single cent,
>>by the way. The 18kg SNC-meteorit simply fell out of the sky in October, 1962
>>near Zagami rock in Nigeria.
>
>I must admit some skepticism wrt meteorites that are claimed to have been
>ejected from Luna and Mars.

Most of the lunar meteorites have been recovered from the Antarctic and
have been compared with the Apollo moon rocks, and they match up very well.
Correlating the SNC meteorites from Mars is on weaker ground, but there
is still evidence that they may very well have come from there.  Last year,
analysis of water from the SNC meteorites provided a stronger case on to
their origin:

RELEASE:  92-35

METEORITES' WATER PROVIDES CLUE TO RED PLANET'S PAST
March 13, 1992

    A single drop of water rarely causes excitement in the scientific
community, but a few milligrams of liquid extracted from a meteorite may
have started to answer one of the great mysteries of planetary science.

    Dr. Everett Gibson of NASA's Johnson Space Center (JSC), Houston,
Planetary Sciences Branch; Dr. Haraldur Karlsson, formerly a National
Research Council postdoctoral fellow at JSC; and scientists at the University
of Chicago have analyzed drops of water extracted from several meteorites
believed to have come from Mars and have concluded that the oxygen
isotopes in the water were extraterrestrial.

    Photographs returned to Earth from the Mariner 9 and Viking
spacecraft show features that suggest Mars once may have had a water-rich
atmosphere and flowing water on its surface.  Sometime in its history,
however, most of the water apparently disappeared, leaving only minute
amounts of vapor in the atmosphere.

    Through the years, several meteorites have been collected on Earth
that scientists have identified as Martian by comparing them to information
gleaned by the Viking spacecraft.  Six of these meteorites were used in the
water extraction procedure.

    Gibson said the meteorites were heated in steps in a small vacuum
system at JSC to extract trace amounts of water.  The water samples were
hand-carried to the University of Chicago for analysis of oxygen isotopes.
Although the water droplets were less than 1/64ths of an inch in diameter,
it was enough to do the analysis.

    The analysis determined that the oxygen isotopes in the water were
different from the oxygen isotopes in the silicate portion of the meteorites.
In other words, the water had a different parent source than the oxygen in
the silicate minerals in the meteorites.  That parent source could have been
the Martian atmosphere, an ancient Martian ocean or even a comet that
impacted the planet, Gibson said.

    The lack of homogeneous oxygen isotopes on Mars supports the theory
that Mars does not have plate tectonics.  If such a process had been active
on Mars, the oxygen isotopes would have been homogenized as they are on
Earth.
     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [e-mail]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Choose a job you love, and
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | you'll never have to work
|_____|/  |_|/       |_____|/                     | a day in your life.

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

Date: 9 Jan 1993 07:19:49 GMT
From: Eidetics Int'l <[e-mail]>
Subject: Dr. Beter AUDIO LETTER archive location
Newsgroups: alt.conspiracy,alt.conspiracy.jfk,alt.activism,talk.politics.misc,alt.rush-limbaugh,alt.fan.rush-limbaugh,soc.history,talk.religion.misc,soc.culture.british,sci.astro,sci.space,sci.space.shuttle

From Jon Volkoff, mail address [e-mail]

To all friends, enemies, and interested individuals in this most controversial
political/economic/military intelligence report, which was recently posted to
alt.conspiracy and talk.politics.misc:

All 80 issues, plus some doc files, are at the moment available by anonymous
ftp from red.css.itd.umich.edu as /poli/dbal.tar.Z

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

Date: Sat, 9 Jan 1993 03:03:46 GMT
From: Jeff Greason ~ <[e-mail]>
Subject: Let's be more specific (was: Stupid Shut Cost arguements)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Edward V. Wright) writes:
>The "extreme mass ratio" is an aerospace legend.  We've been
>building vehicles with similar mass ratios for the last 30
>years.  The Shuttle external tank has the right mass.  So
>did the Saturn S-IVB stage.

I would love to see some convincing evidence of this, as this is the
key risk to SSTO in my opinion -- If I get sold of this, I'll try to
convince my Congresscritter.

Unfortunately, these are not convincing.  I agree it is not a problem
to build just any old structure with mass ratio >>12 (the required range
for H2/O2 rockets).  Aircraft exist that do this (gliders, for example).
Even reusable craft.

However, there are contributors to "dry mass" which SSTO will have which
your test cases won't.  Using OLD technology, these are very significant,
enough to kill your mass ratio.  Using NEW technology, NASP derived in
part, I certainly hope the mass ratio will climb over breakeven point, but
I still regard it as undemonstrated, nor have I seen the evidence which
shows it to be a "low risk" goal.

The contributors I see as significant:

1) A thermal protection system, capable of surviving multiple reentries
   (many) suitable for reuse.  On previous vehicles, this is ablative and
   non reusable, or (on Shuttle), heavy and only marginally reusable.
   NASP composites may combine hull structure with thermal protection, but
   they are new and carry some risk.

2) Low mass cryogenic tanks and insulation.  Yes, the SS ET has the right
   mass ratio BY ITSELF.  However, you have to carry all that tank volume
   IN ADDITION to all the other vehicle dry mass -- this looks slightly
   less attractive, to say the least.  Again, wound composite tanks are
   expected to help here -- but they are new and carry some risk.

3) All the "extra stuff" affiliated with onboard power generation, life
   support, airlocks, etc.  This seems to me to add up amazingly fast with
   a manned presence on board.  This isn't tough, and is traditionally a
   relatively small contributor, but it seems to loom large if we assume,
   in (1) and (2), that the other contributors diminish.

Now, when I say there is risk, this does NOT mean SSTO is not possible,
nor does it mean it's not a good idea.  It just means it's not a sure
thing, nor is it trivially obvious that just "trying to do it" will
achieve the desired result.  Hats off to the engineers if they suceed!
However, I have not seen any convincing argument, based on technology
trends, or detailed analyses of what technological advances are being
depended upon, that the risks are "tolerable" in the sense of a profit
seeking project.

Disclaimer:  All opinions expressed are my own, and do not reflect the
     position of Intel, Portland State University, or Zippy the Pinhead.
============================================================================
Jeff Greason                  "You lock the door ... And throw away the key.
  <[e-mail]>   There's someone in my head, but it's not me."
  <[e-mail]>                -- Pink Floyd

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

Date: 9 Jan 93 03:21:04 GMT
From: Dave Michelson <[e-mail]>
Subject: Mars Observer Update - 01/08/93
Newsgroups: sci.space,sci.astro,alt.sci.planetary

Lines: 11
Sender: [e-mail]
Source-Info:  Sender is really [e-mail]

In article <[e-mail]> [e-mail] (Ron Baalke) writes:
>
>Ka Band Link Experiment (KaBLE) activities have begun and are scheduled
>to take place daily through January 12.  There are additional KaBLE
>opportunities projected for January 16 and 17.

What exactly is the Ka Band Link Experiment onboard the Mars Observer?

---
Dave Michelson
[e-mail]

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

Date: 9 Jan 93 07:13:13 GMT
From: Brian Yamauchi <[e-mail]>
Subject: Small vs. Large Rovers (was Re: How to Explore Mars)
Newsgroups: comp.robotics,sci.space

In article <[e-mail]> [e-mail] (Gerry Roston) writes:
>The
>question of using small robots versus large ones is almost a religious
>question.  The greatest failing of those proposing small robots is the
>naive assumption that using multiple, small robots increases overall
>system reliability.  This is not true because one can not assume a
>priori that the failure modes are independent.  That is, if the robots
>are identical, and one of them fails in a particulr manner, this
>implies that the others will also be prone to that particular failure
>mode.

I'm impressed with what the Ambler group has accomplished, and very
impressed with what the Erebus group accomplished in a very short
amount of time.  I think they deserve a great deal of credit, despite
the unfortunate glitch that ended the test.

That having been said, I'll have to come down on the "small rover"
side of the debate.  (I'll admit to being biased, since I spent a
summer working with the JPL microrover group.)

The failure modes may not be independent, but at least the failure
occurrences are.  Suppose there is a 10% chance that a certain failure
will render a robot immobile sometime during its lifetime.  If you
have a single large rover, you have a 10% chance of losing the rover.
If you have ten microrovers, you will probably lose one, but you only
have a 1% chance of losing all ten of them.

The other advantage of multiple rovers is the ability to obtain data
from several sites at different locations on the surface of Mars.

>From a technical viewpoint, the major drawback to small robots in
>telemetry.  To transmit a signal from Mars, you need a moderately
>large antenna and a bunch of power, if you want reasonable data rates.

How about putting a satellite in Mars orbit and using it as a relay
between the rovers and Earth?  Would that solve this problem?

It seems to me that the primary disadvantage with small rovers is
their inability to carry large scientific payloads.  My opinion is
that this disadvantage is outweighed by the advantages above, but I
suppose it depends upon one's particular interests in research and
exploration.
--
_______________________________________________________________________________

Brian Yamauchi            Case Western Reserve University
[e-mail]    Department of Computer Engineering and Science
_______________________________________________________________________________

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

Date: 9 Jan 93 06:31:41 GMT
From: Henry Spencer <[e-mail]>
Subject: testing rockets
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Edward V. Wright) writes:
>... a typical aircraft
>might fly 400 times before it's declared operational.  How
>long would it take to build and launch 400 expendable rockets,
>even if you could afford to?

Turn it around:  what does it say about current rocket design, when you
(a) can't afford to test them thoroughly, and (b) couldn't do it in a
timely fashion anyway?

Spaceflight will not become cheap and routine until launchers *can* be
tested as rigorously as aircraft.

This will require changes in design approach, not just streamlining of
procedures and economies of scale.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

End of Space Digest Volume 16 : Issue 029
------------------------------