Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V10_4/V10_436.TXT

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Subject: SPACE Digest V10 #436

SPACE Digest                                     Volume 10 : Issue 436

Today's Topics:
                   Re: SSX
          Re: SSX: Space Ship Experimental (summary)
            Re: Cosmic Dark Matter
            Re: NASP Recon. Drones
            Re: booster pollution
     Re: Name The Next Space Station Contest (Forwarded)
            SR-71 aka "Blackbird"
              More SSX comments.
                 Vacuum IC's
            Re: Nuclear Reactors in Space
            Re: Galileo Update - 01/12/90
----------------------------------------------------------------------

Date: 16 Jan 90 20:25:25 GMT
From: tramp![e-mail]  (SERRE GLENN)
Subject: Re: SSX

Wasn't this concept discussed on the net some time ago?  I seem to remember
this along with talk about hydrogen slush for fuel.

Comments on the article:

reference only requiring a small crew to launch:
The current generation of expendables are derived from ICBMs, which required
very small crews to launch.  If you want to keep launch crews and complexity
down, keep the following out of the development process for the SSX:
1) the Air Force
2) any other government agency
3) any organization that represents a satellite manufacturer (at least, a
defense satellite manufacturer).
Only half a :-)

If anyone out there knows of a company that is getting set to design or build
one of these SSXs, please let me know.  I would want to send them my resume.

--Glenn Serre
[e-mail]

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

Date: 17 Jan 90 19:31:48 GMT
From: cs.utexas.edu!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: SSX: Space Ship Experimental (summary)

In article <[e-mail]> [e-mail] (Mike Van Pelt) writes:
>This sounds a whole lot like the "Phoenix" proposal that Gary Hudson
>was involved with a number of years ago.  Is it the same?  ...

Similar.  SSX is an X-plane equivalent, strictly an experimental vehicle
with no operational role, which makes it smaller and a bit less ambitious
than Phoenix.
--
1972: Saturn V #15 flight-ready|     Henry Spencer at U of Toronto Zoology
1990: birds nesting in engines | uunet!attcan!utzoo!henry [e-mail]

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

Date: 17 Jan 90 21:01:39 GMT
From: [e-mail]  (Terry Hancock)
Subject: Re: Cosmic Dark Matter

In article <[e-mail]> [e-mail] (Steve Willner, OIR) writes:
>From article <[e-mail]>, by [e-mail] (Tim Maroney):
>> So many scientists seem to take the dark matter for granted,
>
>
>> but I've yet to see any clear reason for
>> postulating it [a Closed Universe] other than a sort of
>> religious dogma that the universe
>> will eventually recollapse.  Is there really any stronger basis for
>> believing that we only see ten percent of the universe, or are people
>> letting their aesthetics guide their modeling?
>
>
>The second problem is usually called the "Missing Mass Problem."  Even
>accounting for the hidden mass, observable galaxies add up to only
>0.3 or less of the "critical mass," i.e., the maximum mass allowed
>where the Universe expands forever (not recollapses).  As far as I can
>tell, there is indeed no observational evidence for existence of the
>"missing mass;" indeed, there is considerable evidence that the
>"missing" mass, if it exists, cannot be in the form of baryons.  The
>"missing mass" must also _not_ accompany the visible galaxies but rather
>must be more uniformly distributed through the Universe.
>
    Well, there is ONE sort of evidence that I've seen -- the redshift
curve (i.e. the curve relating distance to redshift)  has a different
shape for the open, flat, and closed models.  Unfortunately, this is a
difficult measurement, since it requires an alternate form of distance
measurement -- AND the difference between the curves is only significant
towards extreme distances.  The only distance method I have heard of
being applied to this problem involves the measurement of relative
brightness and the assumption of statistically homogenous galaxy-brightness
both over space and over the history of the universe.   Needless to
say this is a risky assumption.

    HOWEVER, despite all these caveats, the resulting curves that I
have seen loosely support a closed universe.   This (presumably) implies
that we are missing some of the mass which is responsible for the
closure.

    Of course, the observation could be prey to a number of systematic
errors, and I wasn't all that convinced.


>Theorists often (always?) "let their aesthetics guide their modeling."
>What's wrong with that?  The relevant questions are whether models are
>ruled out by existing data and whether simpler models would explain the
>data just as well.  The answer to the first is "maybe" and to the second
>"no".  Models with mass lower than critical invoke either coincidence
>or some other component just as arbitrary as non-baryonic dark
>matter.  Both the "hidden mass" and the "missing mass" questions are at
>the forefront of research these days, which means that nobody knows the
>right answers.

    The whole problem with this area is that there's too little
"existing data" to support the theories.  I'm taking all of it with
a grain (maybe a tonne) of salt until a LOT more observations are
made (and possible).  I don't honestly expect to live long enough to
see a day when I take any cosmological theories seriously.
    Just remember that Ptolemy's universe was not "ruled out by
existing data" for a very long time.  Which, of course, is not all
bad -- a lot of good astronomy was done with the Ptolemaic assumptions.
And, of course, cosmology can be fun, if not correct -- which is probably
why there's so much interest in it (aside from the desire to obtain
a "God's Eye" view of the world, perhaps).

>-------------------------------------------------------------------------
>Steve Willner            Phone [phone]         Bitnet:   willner@cfa
>60 Garden St.            FTS:      830-7123           UUCP:   willner@cfa
>Cambridge, MA 02138 USA                 Internet: [e-mail]

*********************************
Terry Hancock
[e-mail]
*********************************

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

Date: 16 Jan 90 14:38:39 GMT
From: ox.com!itivax!vax3![e-mail]  (Allen W. Sherzer)
Subject: Re: NASP Recon. Drones

In article <[e-mail]> [e-mail] (Steve Rehrauer) writes:

>>There is a secret $3 million Air Force study going on to study the
>>design for a unmanned hypersonic drone that can fly to any continent
>>in under an hour to perform recon. or strikes.

>What does it buy that present or improved satellite recon couldn't?


What it seems to buy is the ability to get recon anywhere on Earth
in around two hours. It's going to be a long time before we will have
any capability to launch a satellite into an arbitrary orbit to take
pictures of an arbitrary point in two hours.

The desirability of this is left as an excercise to the reader.

  Allen
----------------------------------------------------------------------------
| Allen W. Sherzer                    |  Is the local cluster the result   |
|  [e-mail]                        |  of gerrymandering?                |
----------------------------------------------------------------------------

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

Date: 16 Jan 90 19:03:11 GMT
From: clyde.concordia.ca!jarvis.csri.toronto.edu!utgpu!watserv1!watdragon!watyew![e-mail]  (Brian or James)
Subject: Re: booster pollution


  *Sigh* Sorry about the previous posting. Some important sentences got
lost on the way to posting. Let's try this again...

    As well as the chlorine problem, I remember concern about possible
side-effects caused due to NOx compounds produced by boosters. While I
realise that the exhaust from a (for example) hydrogen-oxygen fueled booster
would primarily H2O, would there be significant amounts of other compounds
produced, either from incomplete combustion of the fuel, or chemical reactions
between atmospheric gasses caused by the admittedly transient presence of the
several thousand degree exhaust? Again, from my rather dim memory, I recall
reports of large, temporary holes in the ozone layer forming after launches.
I don't know if these reports were verified.
    Other, more energetic boosters could have some *really* interesting
side effects. Orion would have caused some additional cancer deaths if it had
ever been used as a launching system. Because of the environment Orion was
designed in (pre Atmospheric Test Ban USA), these additional deaths were
felt to be acceptable (and probably difficult, if not impossible, to
detect against the normal cancer rate.). Perhaps France can replace Arianne
with Orion :).
    SF authors use nuclear drives with a charming disregard for safety
(And often physics, as well.). I recall one author whose protagonist said
something akin to "OK, we're over the 'burbs. Turn on the photon drive."
I suspect the author had *no* idea just how much energy the 'thinly populated'
suburbs were about to receive. No wonder they were thinly populated!
    As yet another aside, would there have been any EMP related side
effects from Orion?
                                James Nicoll

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

Date: 17 Jan 90 04:52:44 GMT
From: zephyr.ens.tek.com!wrgate!mrloog![e-mail]  (Dan Tilque)
Subject: Re: Name The Next Space Station Contest (Forwarded)

[e-mail] (Public Affairs Office) writes:
>
>Homer Simpson/Deborah Norville
>Reagan Space Center, Havana, CPFZ            January 15, 1998
>
>
>NASA ANNOUNCES "NAME THE NEXT SPACE STATION" CONTEST
>
>"The replacement Station symbolizes this country's determination not to
>be pushed around any more," Sagdeev said.  "Its name should evoke the
>quest for truth and a zest for lasting dominance."

How about Space Station Gipper.

Is it true that Senator M. Noriega (D-Panama) is trying to kill the new
station?  And if that happens, Vice-President Tyson will punch the
senator's lights out?  Will NASA Select carry the fight on a pay-per-view
basis?

---
Dan Tilque    --    [e-mail]

"The Mars mission won't be cheap -- the cost is currently estimated at
$400 billion, not including reality -- but the potential benefits are
enormous.  For openers, we will earn as a nation, more than 500 million
Frequent Flyer miles."

                -- Dave Barry

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

Date:     Tue, 16 Jan 1990 09:57 EST
From: Donald Simmons <[e-mail]>
Subject:  SR-71 aka "Blackbird"
To: <[e-mail]>

    Hate to say this, but I am not sure what the SR-71 project was all about. I
know that it was some sort of experimental aircraft, but there my knowledge en
Can someone send me a run-down on the project and its history?

Donald Simmons   0C109@AECLCR     Chalk River Nuclear Labs, Chalk River, Ont.

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

Date: 17 Jan 90 17:36:31 GMT
From: agate!shelby!portia![e-mail]  (Raul Izahi Lopez Hernandez)
Subject: More SSX comments.

Hi there!
   Trying to post a follow-up and not succeding again:
    Answering to Henry of Toronto it is interesting to know that
GE (General Electric) is about to announce a new engine which might
be used in the Boeing's '777' plane coming, maybe not so soon though.
So the SSX sounds reasonable when reality can be better than 'fantasy'.
                RAUL IZAHI

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

Date:       Tue, 16 Jan 90 22:55:50 EST
From: [e-mail]
Subject:    Vacuum IC's

Sorry if this comes in a little late. With the Christmas hiatus in SPACE
Digest, I just got caught up with the last 1.5MBytes of it!

A while back, Robert Casey asked a question about work on vacuum integrated
circuits. Leonard Ericson replied to the effect that some work had been done
in the 60's, but implied that interest had died off. Well, not quite. There is
a lot of interest in these things today, which are rad hard like nobody's
business, and mechanically robust to boot. One article I read described vacuum
IC's being exposed to 1e17 n/cm^2 with no degradation in performance. 1e16
would toast most silicon based circuitry. They also ran some of these inside a
furnace at 500C - for 13,000 hours! (That's what the article said, though I
find a year-and-a-half a bit hard to believe!)

     There are apparently two kinds of vacuum IC's - thermionic integrated
circuits, and field emission vacuum devices. (Dammit Jim, I'm an
archaeologist, not an electrical engineer! I don't know what any of these
words mean...) Research is apparently being carried out on these things at GEC
in Britain, at Livermore (why would they be interested?), and Jupiter
Technologies in Austin, TX. (Any people from Jupiter listening?) Lots of other
companies too, I'm sure.

     I don't have an extensive bibliography on the subject. The two articles
that come to mind are: B.C. Cole, Electronics, v62 no12 (1989) p.74-77, and
D.K. Lynn et al., IEEE Trans. Nucl. Sci., vNS-32 no6 (1985) p.3996-4000.

     What I have read suggests that vacuum IC's would be ideal for harsh, high
radiation environments, including space applications. The Van Allen belts, the
neighbourhood of Jupiter, and close (relatively) approaches to the sun should
cause less degradation in their performance than in semiconductor based IC's.
Does anyone know of active research on space based applications of vacuum
IC's? (Now, if only we could get vacuum based solar cells...)

Jeremy Edward
[e-mail]

Disclaimer: I'm always dangerous when I don't know what I'm doing.

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

Date: 17 Jan 90 17:43:49 GMT
From: cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!aplcen!aplvax.jhuapl.edu![e-mail]  (Jim Meritt)
Subject: Re: Nuclear Reactors in Space

In article <[e-mail]> [e-mail] (Tim Maroney) writes:
}what I heard over and over in the mainstream press was on the order of
}1 in 2,000 of a major accident that would breach the containment and
}release plutonium.  Given that such an accident could kill thousands
}of people in the long term, that's nowhere near good enough.  If we

How?

Given that one made it back to earth at 25,000 mph straight down with
noone even noticing, let alone death, what are you going to come up with
that is MORE destructive?


That that is is that that is. That that is not is that that is not.
That that is is not that that is not.  That that is not is not that that is.
And that includes these opinions, which are solely mine!
[e-mail]  - or - [e-mail]  - or - meritt%aplvm.BITNET

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

Date: 16 Jan 90 20:20:04 GMT
From: microsoft![e-mail]  (David LEVINE)
Subject: Re: Galileo Update - 01/12/90

In article <[e-mail]> [e-mail] (Steve Friedl) writes:
>With the talk of the power problems on Galileo, a question came
>to mind.  Let's say that they found some problem with the craft
>that would render its mission to Jupiter useless (say, all the
>cameras died).  If the control and propulsion systems were
>working, is there any way that the craft could be directed to
>enter Earth's orbit on its next flyby and get picked up by the
>Shuttle?  I know that this thing is gonna be going pretty fast,
>but anything seems plausible.

I don't know much about the orbital mechanics, but the mission sounds
too costly and difficult to be worth it.

For starters, don't shuttle missions start at $100 million?  After bringing
it down, it would be torn completely apart and refurbished.  More cost.
Granted, it is a $1 billion spacecraft but it is also fairly old
technology.  It might not be much more expensive to just design one
of the new Mariner Mark II missions for Jupiter.

I think that retrieving Galileo would be the most difficult operation
ever attempted EVA.  In order to stuff it back into the shuttle, there
are about a dozen component that must be stowed.  For starters, the
Magnetometer boom (30 feet long) must be helically wound back up into
its coffee can size contained (OK you could just detach it and leave
it there).  Then, the High Gain Antenna (if deployed) must be stowed.
These two operations are pretty hairy to do on the ground.

Remember that the entire time, the astronauts will be exposed to the
radiation from the RTG's -- a fair amount.  In order to stow or
detatch the RTG booms, they would have to get close to the RTG's
themselves.

This stowing process would take *hours* on the ground -- during
EVA it might not be possible.

Finally, after working on it for over ten years, I think a lot of
people at JPL would rather not have it back at all.  Fortunately,
Galileo looks to be doing OK despite the power problems and I
look forward to a *very* successful encounter in a few years.

David Levine

=====================================================
=== The opinions expressed above are entirely mine ==
=====================================================

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

End of SPACE Digest V10 #436
*******************