Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_2/V15NO280.TXT

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Date: Sat,  3 Oct 92 18:06:40
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #280
To: Space Digest Readers
Precedence: bulk


Space Digest                Sat,  3 Oct 92       Volume 15 : Issue 280

Today's Topics:
                 "Hearing" meteors with your FM radio
                       another sad anniversary
                           Columbia SSME #3
                          Editorial Cartoon
                     Laser Space Mirror (2 msgs)
                         Mars Observer orbit
                 My final word on Ion to Pluto (long)
          NASA Daily News for 09/30/92 (Forwarded) (2 msgs)
               NASA Daily News for 10/02/92 (Forwarded)
                    perot's stand on space funding
                       Psalms from outer space?
       PUTTING VENUS IN AN ORBIT SIMILAR TO THE ORBIT OF THE EA
                           V-2 anniversary
                       Wealth in Space (2 msgs)
         Wealth in Space (Was Re: Clinton and Space Funding)

    Welcome to the Space Digest!!  Please send your messages to
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    (THENET), or [e-mail] (Internet).
----------------------------------------------------------------------

Date: 03 Oct 92 01:51:00 MET
From: Chris Steyaert <[e-mail]>
Subject: "Hearing" meteors with your FM radio
Newsgroups: sci.space

Meteor reflections are normally very short (a few tenths of a second).
Slowly variations should be accorded to the E-layer, air planes, aurora.

Try again, Robert.

  Chris Steyaert
  VVS - Belgium


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

Date: 3 Oct 92 06:55:42 GMT
From: Henry Spencer <[e-mail]>
Subject: another sad anniversary
Newsgroups: sci.space

In article <[e-mail]> [e-mail] ("Patricia Reiff (713")) writes:
>Incidentally, my notes (made several months after the event) said that it
>was Friday Oct 28, not Sept 30, but my recollection could have been faulty.

Sept 30 is the date given in "Where No Man Has Gone Before" (the NASA History
book on Apollo lunar science).  Taylor's "Planetary Science:  A Lunar
Perspective" confirms it... although given the rather limited literature
on ALSEP, it's possible that "ALSEP Termination Report" got it wrong and
both books copied the error from there.
--
There is nothing wrong with making      | Henry Spencer @ U of Toronto Zoology
mistakes, but... make *new* ones. -D.Sim|  [e-mail]  utzoo!henry

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

Date: Sat, 3 Oct 1992 04:04:08 GMT
From: Carl Rigg <[e-mail]>
Subject: Columbia SSME #3
Newsgroups: sci.space

Does anybody know the serial number of the replacement SSME for
engine position #3 on Columbia?
thanks

    Carl

=======================================================================
    Carl    ([e-mail])    (7U-550 415-390-1063)
=======================================================================

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

Date: 3 Oct 92 16:10:14 GMT
From: Tom A Baker <[e-mail]>
Subject: Editorial Cartoon
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (FRANK NEY) writes:
>
>Who else saw the Endeavor cartoon in the 22 Sep issue of Newsweek?
>
>It was good for a laugh if nought else.

I saw.  Reminded me of the Killer Tomato jokes after the tomato seeds
were bnrought back from orbit.  I think recently SNL's Weekend Update
mentioned the same tadpoles ("..showing continued growth...") while
running Godzilla footage.

D'ya think this heightens the public's interest in space?

Tom Baker

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

Date: 3 Oct 92 03:24:53 GMT
From: Frank Crary <[e-mail]>
Subject: Laser Space Mirror
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Ralph Buttigieg) writes:
>Put a flat optical mirror in Clarke orbit. Build a laser transmitters near a
>ground based power station. Beam the generated energy to the mirror which
>can then reflect it to a receiving station. This would be part of a global
>power grid...

I've heard a very similar idea, but beaming the power to other satellites,
instead of back to the ground. That would reduce the mass and increase
the available power of and involved satellite.

                                                Frank Crary
                                                CU Boulder

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

Date: Sat, 3 Oct 1992 07:03:45 GMT
From: Henry Spencer <[e-mail]>
Subject: Laser Space Mirror
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Frank Crary) writes:
>>[laser power beaming]
>I've heard a very similar idea, but beaming the power to other satellites,
>instead of back to the ground. That would reduce the mass and increase
>the available power of and involved satellite.

In this form, it makes considerable sense, and last I heard the notion was
being seriously examined.  It's particularly relevant for things in Clarke
orbit, because much of the mass of their power systems -- the batteries --
is needed solely to carry them through short midnight eclipses for a few
weeks a year.  (Except for short periods bracketing the equinoxes, the
Earth's shadow misses Clarke orbit entirely.)  A few illuminating lasers
on Earth could largely eliminate batteries from Clarke orbit, for a major
savings in weight and hassle.  (Batteries are heavy, temperature-sensitive,
temperamental, and short-lived.)
--
There is nothing wrong with making      | Henry Spencer @ U of Toronto Zoology
mistakes, but... make *new* ones. -D.Sim|  [e-mail]  utzoo!henry

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

Date: Sat, 3 Oct 1992 17:00:16 GMT
From: Frank Crary <[e-mail]>
Subject: Mars Observer orbit
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Dave Rickel) writes:
>I was wondering about that.  Hohmann transfer orbit to Mars is about nine
>months (the CRC says between 230 and 280 days).  Mars Observer is taking
>11 months, which seems to imply that it is going a bit outside of Mars orbit
>and catching it on the inward leg.  What is the reason for this?  (i was
>playing around a bit with xephem, and it looks like there should have been
>an orbit available that was much closer to a Hohmann orbit)

The Hohmann orbits assume the origin and destination are circular orbits in
the same plane. If you account for the slight difference between Earth's
and Mars' orbital planes, you get minimum energy transfer orbits that are
slightly different from a ideal hohmann. Both have an apihelion slightly
beyond Mars' orbit. One stops at Mars before reaching apihelion and
one goes all the way out and comes back to reach Mars. Mars Observer
is apparently on the later sort of orbit.

                                                      Frank Crary
                                                      CU Boulder

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

Date: Sat, 3 Oct 1992 08:01:28 GMT
From: Dave Tholen <[e-mail]>
Subject: My final word on Ion to Pluto (long)
Newsgroups: sci.space

Greg Macrae writes:

>> (a) The issue is cost.  Please tell me how much it would cost to develop
>> and flight-qualify an ion propulsion system appropriate for putting, for
>> example, 100 kg on a 7 year trajectory to Pluto.  Remember, these costs

> Your issue is cost.  Yet you continue to avoid presentation of any cost
> analysis.

When I want to do some science that requires something not already in hand,
I approach one of our instrument builders and ask them what it would
cost to build what I need.  They do the cost analysis.  I write the proposal
to get the funding, and if the proposal is successful, but at a reduced
funding level, then I go back to the instrument builders and ask them for
compromises that fit within the funding limitations, with a goal of minimizing
the impact on the science that can be done.  The Pluto mission has been
through a lot of design and redesign, with each redesign in response to the
likely funding scenario.  The spacecraft designers at JPL are the ones doing
the cost analysis in response to the scientific priorities agreed to by the
scientists.

> I admit that I fully understand why no one in his right mind would
> attempt to present a cost analysis as justification for any project.

The justification for this project is the science that we want to do, not the
cost analysis.  Just because something can be done with a limited budget
doesn't mean that we should do it, if it isn't good science.

> The few analyses
> I have worked on have taught me how to find holes big enough to drive a
> $10,000 toilet seat through in any 'a priori' and many 'a posteriori' cost
> analyses.  I will not do a cost analysis for you, it is a waste of my time.

You say that ion propulsion is better than chemical propulsion.  We say that
we are excited by the prospects for ion propulsion, but have a tight cost cap
imposed by NASA of $400 million, including launch.  So we naturally have to
ask the question of how much it's going to cost to use ion propulsion.  You
say you won't tell us.  Sorry, but we're not in a position to hand out blank
checks.

>> are going to be included in the mission cost.  Yes, we can argue that they
>> shouldn't be, but that's life.  I wholeheartedly agree with the proposition
>> that technology development be decoupled from any one specific mission, but
>> unfortunately you and I don't make these decisions.  For costing purposes,

> Your ignorance is hanging our here.  Huges Research Company developed and
> flight qualified an ion thruster system, including power processors, for use
> in near earth orbit.

But we are looking for a propulsion system for use in deep space, not near
Earth orbit.

> To my knowledge, there is still no user for the system.

Why is that?  It sounds like you are perplexed as to why ion hasn't been
embraced.  May I suggest that you put yourself in the customer's shoes and
ask yourself why you didn't choose ion technology.  You say there are no
valid objections, but the potential customers out there must have some, or
else they would have chosen it.  Right?

> The point is not that this system is appropriate for Pluto.  The point is
> that development money is more often decoupled from specific missions than
> you realize, especially when a research center like Lewis is pushing the
> project rather than a development center like Marshall or Johnson.

This is good news.  Let's hope work on ion technology continues without the
funding from a specific mission.

>> (b) I never said ion propulsion was slow.

> Correct, you didn't.  I did not accuse you of that particular faux pas.  I
> don't recall who or how many did, and I don't really care.  The claim
> occurs rather frequently.  Analysis has shown that it is incorrect.  I
> posted on this subject in the hope that I can erase some misconceptions.  I
> am more opposed to misinformation than I am to you personally :).

Likewise!  I have other outer Solar System interests, like Chiron, Pholus,
1991 DA, and 1992 QB1.  Who knows, maybe someday we'll be collaborating on
an ion-driven spacecraft to one of these objects.  No sense starting off on
the wrong foot!

>> Theoretically, ion is great for fast Pluto missions.  I don't recall anybody
>> claiming that it was not appropriate.  Practically speaking, however, the
>> technology demonstration has yet to be done, and that is a very valid
>> objection.

> More phantom claims that the technology has not been demonstrated...  We have
> demonstrated >10,000 hr life,

Sounds like an automobile dealership advertising something for "under $10,000",
and it turns out to be $9,999.  Just how much longer than 10,000 hours is the
rated life?  10,001?  20,000?  100,000?  10,000 hours is just 417 days, and
I've yet to see a claim that we can get to Pluto in 417 days.  What fraction
of the time are you coasting?  You did quote from an internal study, that an
ion-driven spacecraft could deliver twice the payload INTO ORBIT around Pluto
in half the travel time.  So half the rated lifetime would be used to
decelerate.  What about the storage lifetime?  If the propulsion unit is to
go unused for a long stretch of time, how reliably can it be restarted?  If
the unit is to be used in a pulsed mode with a low duty cycle, does the
10,000 hours represent the total lifetime or just that fraction when it's
actually thrusting?

How many times has >10,000 hour life been demonstrated in real-life
conditions, as opposed to laboratory conditions?  With just one prototype
unit?  How is reliability assessed?

> characterized operation on different fuels,
> demonstrated 88:1 throttling, built thrusters up to 50 cm in diameter,
> designed for zero performance variation over the thruster life, etc.
> Is there something that must yet be demonstrated that is generic to all (or
> even many) missions?  This is a genuine question that we have here.  We want
> to know if we are overlooking something big that we shouldn't overlook.

Sufficient lifetime to do a Pluto mission; 10,000 hours may not be enough.
Also, reliability.  How much of a track record does ion have?  Just SERT-2?

>> When the Outer Planets Science Working Group had its
>> presentation from the ion drive folks, the cards were laid out on the table
>> and the group collectively assessed the situation and felt that the time was
>> not yet right, while at the same time thinking highly of the prospects.

> I am getting tired of your raising the OPSWG as a method of validating your
> claims.

I'll take OPSWG over sci.space any day.  NASA hasn't put fools on this working
group.  I have a great deal of respect for these people.

> I have heard enough blathering to conlude that you either did not
> attend the propulsion sessions or you slept through them.

Hold on there.  The difference between a response and a flame is the usage
of words like "blathering".  And your conclusion is quite false.  I was both
there and awake.  And I continued the discussion with the presenter in an
informal way during dinner that evening.  I summarized the situation as a
Catch 22.  Nobody wants to be the first to use ion because of the risks
involved, so the funding to finish the development of the technology to
eliminate those risks hasn't been forthcoming.  He indicated that that was
a reasonably accurate summary of the situation.  Note that what you and we
consider to be "technology development" may not reflect the same level of
completion.  For example, I'm often hearing of technology demonstrations by
software vendors (IBM or Microsoft, for example), but a lot of fine-tuning
is still needed before such products are actually released for real-world
usage.  Apparently the presenter agreed that ion still needed some work
before it could be realistically utilized with a high degree of confidence.
This presentation was a year and a half ago, however.  If the situation has
changed signficantly, it's time for a updated presentation.  Note that when
I say just ion, I'm referring to the whole package, including the power
source.  For example, the folks at Sun may consider their Sparcstations
to be developed technology, but if the intended use is far from any AC
outlet, the customer will go looking elsewhere.  Ion may be ready, but if
there isn't a practical power source, what good does it do?

> The biggest detraction
> that ion thrusters currently face is the power supply requirements.
> For Pluto missions, PV arrays obviously will not suffice.  That pretty much
> leaves nuclear sources.  Furthermore, the low mass efficiency of RTG's
> combined with the high power requirements drive you to a nuclear reactor as
> the power source.  The biggest issue facing ion thrusters for interplanetary
> missions is qualifying a nuclear reactor for flight.  Even that is more of a
> political issue than a cost issue.  Although the political aspect tends to
> drive the cost far higher than is technically necessary.  This is the ONLY
> issue that I have seen that is big enough to kill ion for Pluto without
> any further analysis required.

Even RTGs trigger the political aspect, so there must be more to it than
just that.  One issue that was raised with regard to RTGs was that unlike
Voyager, whose RTGs were boom mounted to get them as far away as possible
from sensitive instrumentation, the Pluto spacecraft is quite small, with
RTGs body mounted.  Depending on the type of instrumentation, more shielding
may be required, which adds mass, which translates into cost.  The nuclear
reactor you're talking about will also add mass.  At what tradeoff?  Smaller
payload?  Is the mass of ion's propellant, compared with chemical, less by
enough to compensate for the mass of the reactor?  Do you lengthen the travel
time or use a more powerful launch vehicle?  All of these issues eventually
translate into higher cost, which is what I've been saying all along.

> In all fairness to Mr. Tholen, ion seems to get a bad rap largely because it
> has been in development since the mid 1950's and the only real ion mission
> so far has been SERT-2. The thruster was radically different from modern
> thruster technology.  The common assumption is that the technology
> must be immature for it not to have flown.

Again, I suggest putting yourself into the shoes of the customer to try and
determine why it hasn't been chosen for flight.  If the customers' reasons
aren't valid, then somebody isn't doing their job right.

> It tends to be dismissed almost
> out of habit when missions are being planned, and it has never recieved the
> focussed monetary attention that a major mission can offer.  It is probably
> inapropriate for a near term mission to Pluto (unless someone is willing to
> fly a Topaz reactor:) ).  It is also very difficult to optimize a low thrust
> trajectory, whereas any high school graduate can solve the two body problem
> on a hand calculator for a reasonable impulsive mission approximation.  This
> makes it more time consuming and expensive to compare electric propulsion in
> any meaningful fashion.  Also, fewer people can do it.  This often leads to
> an inadequate basis for comparison.
>
> This is my bitter response to what I see as uninformed ion bashing.  I
> apologize if it is too close to a flame.  Judgeing from the recent decline
> in ion posts, interest is waning.  If anyone has further questions for ME,
> about ion, please E-mail them.

I hope you haven't concluded that I've been bashing ion.  I said it before
and I'll say it again:  I think it's great technology, and that further work
shouldn't be tied to the "focussed monetary attention that a major mission
can offer".  (By the way, Pluto is not considered a major mission; NASA has
its different categories based on cost; Cassini is a flagship mission, for
example, but Pluto is not; it is above the Discovery class, however.)  I have
merely been defending my colleagues who have decided that chemical propulsion
is good enough to get the job done, and at lower cost.  We have no doubt that
we CAN fly a better mission, but "better" almost certainly means higher cost.
I'm not naive enough to claim that we've perfectly optimized the mission
(especially when there are conflicting scientific views as to what are the
most important measurements to make), but with the threat of not having a
mission at all if we come in too expensive, we're trying our very best.

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

Date: 3 Oct 92 04:10:48 GMT
From: Frank Crary <[e-mail]>
Subject: NASA Daily News for 09/30/92 (Forwarded)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>>... the second shuttle mission for a CSA astronaut -
>>the first having been STS-41G in October 1984 with payload specialist
>>Marc Garneau...
>If I were Roberta Bondar, I'd be annoyed about being omitted...

I seem to have missed something: The only "CSA" I'm familiar with
is the Confederate States of America, but they haven't existed for
a good 127 years... They do still seem to have an air force despite
this, but I hadn't heard of a space program...

                                                 Frank Crary
                                                 CU Boulder

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

Date: Sat, 3 Oct 1992 07:22:35 GMT
From: Henry Spencer <[e-mail]>
Subject: NASA Daily News for 09/30/92 (Forwarded)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Frank Crary) writes:
>>>... the second shuttle mission for a CSA astronaut -
>
>I seem to have missed something: The only "CSA" I'm familiar with
>is the Confederate States of America...

Think hard, Frank. :-)  What does "SA" stand for in acronyms like NASA
and ESA?  Okay, that's two letters out of three.  Now, think real hard
about what countries starting with C fly astronauts on shuttle missions.
(No, Virginia, there will be no prize awarded for silliest suggestion.)
Looking up what country Steve MacLean is from is cheating. :-)
--
There is nothing wrong with making      | Henry Spencer @ U of Toronto Zoology
mistakes, but... make *new* ones. -D.Sim|  [e-mail]  utzoo!henry

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

Date: Sat, 3 Oct 1992 07:16:07 GMT
From: Henry Spencer <[e-mail]>
Subject: NASA Daily News for 10/02/92 (Forwarded)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Peter E. Yee) writes:
>... MacLean will be the third
>astronaut from the CSA to have flown on a shuttle mission.  The first,
>Patrick Baudry, flew on Discovery in June 1985 on the STS-51G mission.
>Roberta Bondar was next, flying on last January's STS-42 mission, again
>aboard Discovery.  (On Wednesday, Daily News erroneously reported
>MacLean would be the second CSA astronaut to fly.)

Okay, now it's Marc Garneau's turn to be annoyed by botched NASA reporting.
Maybe on the third try they'll get it right.
--
There is nothing wrong with making      | Henry Spencer @ U of Toronto Zoology
mistakes, but... make *new* ones. -D.Sim|  [e-mail]  utzoo!henry

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

Date: 3 Oct 92 01:48:10 GMT
From: Herman Rubin <[e-mail]>
Subject: perot's stand on space funding
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Alex Falkenberg) writes:
>Does Perot have a position on space funding?  Not that I'm going to vote
>for him or anything, but it would be interesting to know given the other
>questionable stances he has taken...       -agf (just a lowly student,
>perhaps forever...)

According to his recent statements, we should not spend any money on
anything "impractical" until the deficit and budget problems are
completely resolved.  Space was specifically mentioned here.
--
Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907-1399
Phone: [phone]
[e-mail] (Internet, bitnet)
{purdue,pur-ee}!snap.stat!hrubin(UUCP)

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

Date: 3 Oct 92 16:16:08 GMT
From: "Frederick A. Ringwald" <[e-mail]>
Subject: Psalms from outer space?
Newsgroups: sci.space

In article <[e-mail]>
[e-mail] (Bill Higgins-- Beam Jockey) writes:

> The best I can come up with is that some passages from Genesis were
> read byt the Apollo 8 crew on Christmas in 1968, but I have no record
> that they read Psalms or any other part of the Bible.

And it was SO much more appropriate than a rousing chorus of "Santa
Claus is coming to town," which it is RUMORED ground controllers were
afraid they were going to get...

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

Date: 3 Oct 92 03:21:25 GMT
From: Frank Crary <[e-mail]>
Subject: PUTTING VENUS IN AN ORBIT SIMILAR TO THE ORBIT OF THE EA
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Kenneth Freeman) writes:
>> I think the accepted theory starts with the loss of carbon dioxide to
>> geological processes: This gas disolves into oceans (Mars of 3.7 billion
>> years ago had such oceans), and reacts with disolved calcium to form
>> calcium carbonate rock. On Earth, there is a balance, because plate
>> techtonics result in the subduction of ocean floors, the melting of
>> calcium carbonate rock and the subsequent venting of carbon dioxide out
>> of volcanoes. On Mars, which lacking such an active geology, the carbon
>> dioxide is simply removed from the atmosphere and sits on the bottom of
>> the oceans (while they last). By pulling a major greenhouse gas out
>> of the atmosphere causes a major drop in temperature and other
>> atmospheric components (such as water and more carbon dioxide during the
>> winter) freeze out. The result is an trend a colder and thiner
>> atmosphere. (Of course, this mechanism works only as long as there are
>> oceans. After a point, the atmosphere is too cold and thin to sustain
>> them, and other loss mechanisms must have taken over.)

>Just as a thought experiment, how much water would have to
>be poured onto Mars for the resultant oceans (or ocean, if
>that's what it takes) for the water to stay there by virtue
>of its own mass?

I'm not quite sure what you mean by "stay there by virtue of its own
mass." Presumably, most of the water is still there (though no longer
as a liquid, but as polar caps, permafrost and _possibly_ a subsurface
water table.) If (somehow) the planet were to become warmed, this
water would be liberated and form oceans again (is enough is left,
only one ocean: The northern hemisphere is, on average, lower than the
southern, and there is evidence that the entire northern hemisphere
was once a single ocean.) Of course, this would be an unstable
situation, and the planet would cool and dry again, over the course of
millions of years. From a human perspective, however, a million years
and "forever" are not too different...

                                                  Frank Crary
                                                  CU Boulder

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

Date: 2 Oct 92 19:33:45 GMT
From: Bruce Watson <[e-mail]>
Subject: V-2 anniversary
Newsgroups: sci.space

Trivia question: Which city was targeted and hit by the most number
of V-2s?

--
Bruce Watson (wats@scicom)  Tumbra, Zorkovick; Sparkula zoom krackadomando.

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

Date: Sat, 3 Oct 92 00:21:02 -0500
From: [e-mail] (Phil G. Fraering)
Subject: Wealth in Space

Paul Dietz writes:

\HOWEVER: for fundamental reasons (having to do with space charge
/limits on currents) the throughput of a conventional mass spectrometer
\is miniscule (think: if it were not, anyone could enrich uranium on
/the scale of a lab bench).  In any case, the energy required to
\vaporize an asteroid would be immense, hand waving about mirrors
/notwithstanding.  The idea is basically stupid.

I was thinking, though, along with others, that you could quite easily
make the mass spectrometer really large as in "space is big"
large.

Anyone have any comments on large flimsy structure mass spectrometers?


--
Phil Fraering [e-mail] where the x is a number from 1-5.
Phone: [phone] SnailMail: 2408 Blue Haven Dr., New Iberia, La. 70560
---------------------
Disclaimer: Some reasonably forseeable events may exceed this
message's capability to protect from severe injury, death, widespread
disaster, astronomically significant volumes of space approaching a
state of markedly increaced entropy, or taxes.

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

Date: Sat, 3 Oct 1992 18:33:27 GMT
From: Paul Dietz <[e-mail]>
Subject: Wealth in Space
Newsgroups: sci.space

In article <[e-mail]> [e-mail] ("Phil G. Fraering") writes:

> I was thinking, though, along with others, that you could quite easily
> make the mass spectrometer really large as in "space is big"
> large.
>
> Anyone have any comments on large flimsy structure mass spectrometers?


The problem there is that you then need to make the *magnets* really
large.  There is no gain in doing so; the mass of the magnets will be
proportional to the volume x the square of the magnetic field.  Also,
you still need to vaporize and ionize the material.

    Paul F. Dietz
    [e-mail]

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

Date: 3 Oct 92 00:43:50 GMT
From: Herman Rubin <[e-mail]>
Subject: Wealth in Space (Was Re: Clinton and Space Funding)
Newsgroups: sci.space,sci.astro,talk.politics.space,alt.politics.bush,alt.politics.clinton

In article <[e-mail]> [e-mail] (bill nelson) writes:
>[e-mail] (Tom Horsley) writes:

            .........................

>Will a mass spectrometer work in the absence of a strong gravitational field?

It has been a LONG time since I learned about mass spectrometers, but I do not
see how a gravitational field would have any substantial effect.  In fact, the
equivalence between gravity and acceleration would mean that it would have to
be a highly non-constant field to even hope to make a difference.
--
Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907-1399
Phone: [phone]
[e-mail] (Internet, bitnet)
{purdue,pur-ee}!snap.stat!hrubin(UUCP)

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


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>: you got your limitless solar power, you got your zero-G environment.  All
>: you gotta do a setup a few solar mirrors, vaporize the sucker, and run the
>: vapor through a free floating mega-industrial scale mass spectrometer

>Will a mass spectrometer work in the absence of a strong gravitational field?
>I guess you could rotate the spectrometer fast enough to make use of the
>centripital/centrifical forces.


Mass spectrometers have nothing to do with gravity.  They use
magnetic fields to separate an ion beam according to the charge/mass
ratio.

HOWEVER: for fundamental reasons (having to do with space charge
limits on currents) the throughput of a conventional mass spectrometer
is miniscule (think: if it were not, anyone could enrich uranium on
the scale of a lab bench).  In any case, the energy required to
vaporize an asteroid would be immense, hand waving about mirrors
notwithstanding.  The idea is basically stupid.

    Paul F. Dietz
    [e-mail]

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End of Space Digest Volume 15 : Issue 280
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