Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V10_2/V10_287.TXT

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Subject: SPACE Digest V10 #287

SPACE Digest                                     Volume 10 : Issue 287

Today's Topics:
        Re: Asteroid strikes and warning times
               Re: Oct 9 AW&ST
             Re: Reasons for Mars mission
             Re: Reasons for Mars mission
           Re: Re: Re: Why NASA wants to go to Mars
           Re: Looking Down [was: Re: HST resoluti
      Re: Building a space station--how big and how-to?
          Re: Antimatter Drives and Area 51
           Re: Why NASA wants to go to Mars
             Re: shuttle question
----------------------------------------------------------------------

Date: 27 Nov 89 12:58:10 GMT
From: spdcc!ftp!poopsie![e-mail]  (Seth D. Hollub)
Subject: Re: Asteroid strikes and warning times

In article <[e-mail]> [e-mail] (Patrick A. Hillmeyer) writes:

> [Asteroid strike discussion....]
> ...
>  After all, if there was very little warning or none at all, the first
>indication would detection of a fast moving, inbound object toward the target
>area and then reports of massive destruction.  What would keep the
>unfortunate
>target country from thinking it was under attack (especially if tensions were
>already high due to other reasons)?

The folks at _Bulletin_of_the_Atomic_Scientists_ often say that nuclear
detonations produce a characteristic "double flash". Something about the
first condensation shell forming, blocking the light, and then literally
being blown away by the force of the explosion. This produces a second
flash milliseconds after the first. Conventional explosions are said
to produce a single flash. (I guess a meteor would produce a third class
of flashes, but not two closely spaced ones).

Supposedly our military warning satellites can see this (all the better).
This is why we think the South Africans really did set off a bomb in 197(9?).

So, while we may not have much warning, if our military network still
functioned afterwards they might know that it was not *human* folly which had
produced the result.

>Are there any kind of US/Soviet or
>international/UN agreements on this type of thing? Does anybody know what the
>military has in the way of detection capability for objects coming in from
>space?  Are there any contingency plans for contacting the Soviets
>immediately

Do you want to phone them, or should I? (Active smiley compensation -> ;-)

"Careful with that ax, Eugene; I don't get sci.military."
-----------------------------------------------------------------------------
       Space station: 250 miles / 30 Billion dollars = $1900 / inch.
[e-mail], ...ftp!poopsie!seth, 18 Rindge Av, Camb. Ma, 02140 USA Earth

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

Date: Tue, 28 Nov 89 19:03:22 EST
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Re: Oct 9 AW&ST


>From: cs.utexas.edu!jarvis.csri.toronto.edu!ists!yunexus!utzoo![e-mail]  (Henry Spencer)
>Subject: space news from Oct 9 AW&ST, part 1

>Initial NASA assessments indicate that using the space station as a
>staging base for lunar operations would have "a significant impact".
>The estimated cost of design changes is about $1G; they would include
>more power, more heat radiators, upgrades to life support to handle
>14-16 astronauts temporarily, and construction of the lower part of
>the old "dual keel" design to accommodate docking facilities for
>Shuttle-C and a servicing facility for a lunar transfer vehicle.
>The extra hardware would have to go up pretty much immediately on
>completion of the basic station if lunar activity starts on the
>schedules some are projecting, circa 2000.  There is debate about
>whether using the same platform for lunar operations and microgravity
>research is really a good idea.  ESA is uneasy about whether lunar
>support will divert NASA attention and money away from research work.
>Lenoir says NASA has rather mixed feelings about simultaneous requests
>to save money on the space station and to expand it to support lunar
>exploration; he says one or the other will have to give.

I am somewhat of the opinion that use as a staging base for more distant
missions is one of the few really plausible justifications for a manned
space station. While microgravity research is important, much of it can
be done more cheaply (unmanned missions, periodically-visited craft, or
much more limited space station). In addition, the vibrations and "air
pollution" associated with a manned craft make it unsuitable for certain
space experiments. A staging base in LEO could be very useful, especially
with the limited payloads of current US launchers. The $1 billion price
tag sounds like a small incremental cost to make the space station into
something that could actually be useful for other missions. (Assuming, of
course, that this is not the estimated increase in cost for the design
process alone. :-)

>A graph of US scientific launch activity in the last 30 years is somewhat
>striking.  From 1958 to 1978, the longest gap between major exploration
>missions was one year.  Between Pioneer Venus in 1978 and Magellan this
>May... nothing.
There is a strong tendency to consider the actual launch the only significant
part of a scientific space project. This is partly because launches have been
very difficult to obtain in the last few years, making them the bottleneck
for several projects. I consider the design and construction of the craft,
the control process after launch, and the analysis of the data to also be
very important. During this time, HST, Galileo, etc. were being constructed
and modified, and there were several ongoing missions, such as Voyager.
I'm not trying to defend the low level of support during this interval.
I just think that launch rate is a very poor single measure of the state
of space science at a given time.
                                 John Roberts
                                 [e-mail]

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

Date: 29 Nov 89 22:11:20 GMT
From: bfmny0![e-mail]  (Tom Neff)
Subject: Re: Reasons for Mars mission

Daniel Mocsny's remarks about the ocean floor are in line with my
thinking.  As I remarked a couple of weeks ago, REMEMBER CONSHELF II!
That's when the real space program died.  A species truly interested
in exploration for its own sake would never have let that program
die after the first missions.  My only real objection if we *did*
suddenly have a change of heart and start moving onto the shelves
in a major way is that it'd screw up the ecology even more.  But
it would be hard to beat our drilling for effect anyway.

Considering that it's easier and cheaper to inhabit the shelves than
the equivalent acreage on Moon or Mars, I wonder why people don't
spend more time pondering "self sufficient colonies" and "population
pressure relief" efforts down there.  Is it because undersea homes
would be depressing, sunless ant tanks?  Oh gee, what happened to
our "I never go outside and I like it" contingent?! :-)
--
To have a horror of the bourgeois   (\(    Tom Neff
is bourgeois. -- Jules Renard        )\)   [e-mail]

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

Date: 29 Nov 89 05:42:22 GMT
From: fox!portal!cup.portal.com![e-mail]  (Patrick John Horgan)
Subject: Re: Reasons for Mars mission


    When I was a kid in the fifties and sixties, I assumed that by
this time there would be viable long-term colonies on the moon, and
the beginning of colonization on Mars.  In between I've cherished a
few dreams about the asteroids as well.  Well, that kind of investment
doesn't happen because it's a dream of mine!  But I know that there
are a lot of people just like me (some who have much more "acceptable"
arguments to use for camouflage), who want us in space because it's
a place for us to go.  I know that doesn't sound real logical...but
dreams seldom are.

Patrick - How I'd love to be able to go - Horgan

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

Date: 29 Nov 89 15:42:59 GMT
From: groucho![e-mail]  (Steve Emmerson)
Subject: Re: Re: Re: Why NASA wants to go to Mars

[e-mail] (Peter Scott) writes:

>Why should it have a profit motive?  Granted this governs most of our
>activities, but might there not be a little more to human nature than the
>desire to turn a buck?  Not a lot of profit motive in climbing Everest
>(I doubt they did it for the TV rights), but it happened anyway.

I was responding to an article that described the exploration and
development of space as being somewhat analogous to the exploration and
development of the New World.  I wanted to point out a difference:
namely, that the New World operation was, for the most part, privately
funded.

Incidentally, the same analysis holds for your Everest analogy.

I believe the poster of that article would agree with you -- that there
are reasons for space exploration which lie outside the relm of
profit.  I, too, am sympathetic to such reasons; the matter is one of
degree.  When the money comes out of my pocket, I want very strong
reasons indeed -- and a program I can support.

-----
Steve Emmerson        [e-mail]

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

Date: 29 Nov 89 15:33:32 GMT
From: frooz![e-mail]  (Bill Wyatt)
Subject: Re: Looking Down [was: Re: HST resoluti

>>Just a second here.  I agree that the HST would have a resolution on
>>earth of ~6 inches, but dont DoD Spysats have a resolution of about
>>2 inches?  Why dont we just tell the DoD to point one of em at whatever
>>astronomers want to look at? [...]
>
> That would be  great idea, except that the DoD satellites probably don't have
> that kind of resolution, but if they did, they would have visual light and
> infra-red cameras. Visual light is more or less a back-seat kind of field
> right now- it's all UV or x-ray or radio, with some IR.

WHOA BABY - `Visual light' (astronomers use the term `optical', by the
way) is most definitely NOT a `back-seat kind of field'! Why else
would the HST be going up? As it stands, there's lots of emphasis on UV
and X-ray satellites because you have to get above the atmosphere to do
anything at all. There's several very large ground-based optical
telescopes being built (Keck, VLT, ARC) or planned (numerous). No
non-optical source is considered confirmed until its optical counterpart
is identified and (preferably) an optical spectrum obtained.

>                                                          Even the IR cameras
> might not help much, becasue their peak sensitivity range would be great for
> seeing car or tank exhaust, which might be a very boring region of the astro-
> nomical sky.

The biggest problem is likely to be the source intensity the IR camera
is designed for, and the accuracy with which measurements can be made.
Getting accurate (`photometric') data on faint objects is a different
measuring regime from simple detection, and requires much more care in
instrument and sensor design and selection.

It's also probably true that DoD sensors have a more limited sensitivity
range than astronomers want/need.

> [... discussion of pointing control problems ...]
> Even if all these problems are overcome, the DoD satellites just aren't
> designed for astronomical work. I don't think they have the pointing accuracy
> necessary for long-durational photography.

Also likely true. The guide-star problem has been one of HST's headaches
for a long time (see the current _Sky_and_Telescope_ article on the
just-released Guide Star Catalog).

Bill Wyatt, Smithsonian Astrophysical Observatory  (Cambridge, MA, USA)
    UUCP :  {husc6,cmcl2,mit-eddie}!harvard!cfa!wyatt
    ARPA:   [e-mail]
    SPAN:   cfa::wyatt                 BITNET: wyatt@cfa

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

Date: 29 Nov 89 20:03:17 GMT
From: ogccse!emory!mephisto!prism![e-mail]  (THOMAS, PETE (TEACHING ASSISTANT))
Subject: Re: Building a space station--how big and how-to?

In article <[e-mail]> [e-mail] (Bill Wyatt) writes:
>The recommendations by space scientists to NASA have always been for
>free-flyers...

AKA--current sort of ideas, like satelites, etc.?  NOT connected
to the station (perhaps putting them relatively close by, so that
you have some of the advantages of manned craft--fast repair,
adjustments/modifications?  Seems like that is likely what will
happen.  Thanks.

>However, science (this sort, anyway) is NOT a reason
>for the space station to exist.

Or at least not THE driving reason--let's stipulate in our
discussion that we want the station to be economically
feasible--and eventually a profit-maker...Now, how do you fund
it?  Government?  A (large) private syndicate?

--
Peter L. Thomas (E GR 1170Z{1,2}, UTA)
"Figures never lie, but liars always figure."
Georgia Institute of Technology, Atlanta Georgia, 30332
Internet: {gt5139c,ce202a2}@prism.gatech.edu

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

Date: 29 Nov 89 07:32:56 GMT
From: cs.utexas.edu!samsung!rex!uflorida!beach.cis.ufl.edu![e-mail]  (Bob Slaughter)
Subject: Re: Antimatter Drives and Area 51

In article <[e-mail]> [e-mail] (W.T. Higgins) writes:
>
>Unfortunately, it turned out to be a bust.  We showered muons on our 115
> sample rods for weeks on end.  The decay chain ends, after a rather short
>time, at 106Pd. And Pd has a tremendous affinity for hydrogen, and
>anti-hydrogen.  We had made a bunch of antimatter, but we couldn't
>get it out. The deuterons were stuck within the Pd lattice.  All we could
>collect were a few deuterons coming off atoms on the surface, and positrons,
>which we can get anywhere.  And instead of an exotic heavy element, we were
>left with an inert lump of a metal anybody can buy on the commodities market.
>  Remember the joke about the alchemist who could turn gold into lead?

Yeah, but if you had dropped the hydrogen laden Palladium lattice in a sink
along with some electrical appliance, you could've invented cold-fusion with
and added bang!  :)

>...  The sample rods were lying around the lab for a while,
>though, come to think of it, I haven't seen them in a couple of years.  I
>suppose somebody scrounged them for another experiment.

I wonder where Fleischmann and Pons got their rods....




--
*     Bob Slaughter                           *  This space for rent       *
*     InterNet#1:  [e-mail]      *    Call 1-800-FOR-RENT     *
*     InterNet#2:  [e-mail] *   Model Railroading        *
*     Bitnet:      Haldane@UFPine             *          is Fun!!          *

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

Date: 29 Nov 89 20:01:25 GMT
From: uhccux![e-mail]  (Jeff Goldader)
Subject: Re: Why NASA wants to go to Mars

In article <[e-mail]> [e-mail] (John McKernan) writes:
>In article <[e-mail]> [e-mail] (Jeff Goldader) writes:
>>In article <[e-mail]> [e-mail] (douglas.h.price,45261,ih,6x203,312 979 3664) writes:
>>>[Douglas says that nuclear propulsion would cut the Mars mission price to
$150 Billion]
[and I said...]  >>And at that price, even *I* would say, "GO!"
>
>Anybody with a clear view of NASA's past and present would say "NO" at any
>price. Putting four people on Mars to take a quick look around and then leave
>is exactly what we accomplished with Apollo. Ie we put on a big show and
>showed what we are capable of, but we didn't actually end up with anything
>solid after all our effort and expense.

Like I said a few lines later in my posting, I feel the real good to come out
of such a mission would be the development of the propulsion system.  Then,
"all" we have to do is get the money to use it wisely.

Jeff Goldader                        University of Hawaii
[e-mail]      Institute for Astronomy

"So, Lonestar, now you see that Evil will always win- because Good is stupid."
-The Dark Lord Dark Helmet, _SPACEBALLS_

Disclaimer: The University of Hawaii and the Institute for Astronomy neither
support nor are in *any way* responsible for these opinions.

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

Date: 29 Nov 89 17:11:35 GMT
From: hp-pcd!hpcvia![e-mail]  (ken_scofield)
Subject: Re: shuttle question

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

>Ack!
>
>The space shuttle main engines have internal spark igniters, ...
> [...stuff deleted...]
>The *real* reason for the pyrotechnics is to ignite any hydrogen
>gas escaping after a launch abort.  If it were not ignited, it
>might accumulate and explode.
>
>    Paul F. Dietz
>    [e-mail]

  OK, dumb question time.  I've repeatedly heard that the shuttle main engines
  cannot be restarted once shut down.  The presence of a spark plug implies
  that it should be possible to restart.  So, other than the obvious problem
  of having no fuel once the tank is dropped, is there some other fundamental
  reason why the SSME's can't restart?


             *
            / \
       |---/---\---|            Ken Scofield    C-9355
       |   Gone    |            Hewlett-Packard, ICO
       |           |            1020 NE Circle Blvd.
       |  Jumpin'  |            Corvallis, OR  97330
       |-----------|            Phone:  [phone]
            ucbvax!hplabs!hp-pcd!kas
                        [e-mail]

Cute Disclaimer:  Nobody ever listened to me before, so why start now?

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

End of SPACE Digest V10 #287
*******************