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Subject: SPACE Digest V10 #112

SPACE Digest                                     Volume 10 : Issue 112

Today's Topics:
              Stability of Pluto's orbit
              NSS Hotline Update 9/29/89
        Re: power source for the space station
               Re: Human contamination?
             Re: Concorde, NASP, shuttles
               Re: Human contamination?
             Re: Concorde, NASP, shuttles
       Re: NASA Headline News for 09/27/89 (Forwarded)
          Re: Toxic materials on the Shuttle
     Re: Trying to build a fluxgate magnetometer -- help!
               Re: Human contamination?
----------------------------------------------------------------------

Date: 1 Oct 89 22:42:26 GMT
From: bunny![e-mail]  (Horace Dediu)
Subject: Stability of Pluto's orbit

Regarding the recent discussion on the possible collision of Pluto and
Neptune:  It's quite obvious that the two orbits now do not intersect, but a
closer look at Pluto's orbit helps predict if the orbits will never
intersect.  I just came across a paper which discusses the design and
construction of a digital orrery, which can calculate solar system orbits
for hundreds of millions of years in advance.  The following is a quote from
this paper:

"We built the Orrery as a cost-effective instrument to attack questions
about the dynamical state and long-term stability of the solar system.  For
example, the stability of the orbit of Pluto is an open question.  The
perihelion of the orbit of Pluto lies within the orbit of Neptune.  Unless
prevented by some mechanism, a close ecounter between the two planets will
eventually occur, and the orbit of Pluto will be disrupted.  In a 120000
year numerical integration, Cohen and Huppard discovered a stabilization
mechanism based on the fact that the orbits of Pluto and Neptune are in a 3/2
resonance--that is, Pluto makes two orbits for every three of Neptune.  The
origin and stability of this resonance over the age of the solar system is
still an open question.  Indeed, did Pluto form in the resonance or was it
later caputured into it?  The solution will shed light on the formation and
evolution of the solar system."[1]

Another paper gives the following results:
"The Digital Orrery has been used to perform an integration of the motion of
the outer planets for 845 million years.  This integration indicates that
the long-term motion of the planet Pluto is chaotic.  Nearby Trajectories
diverge exponentially with an e-folding time of only about 20 million
years."[2]

I would conclude that although the orbit of Pluto is chaotic, it will not
intersect the orbit of Neptune within the forseable life of the solar
system.

[1]  James H. Applegate, Michael R. Douglas, Y. Gursel, Peter Hunter,
Charles L. Seitz, Gerald Jay Sussman
A Digital Orrery
IEEE Transactions on Computers
Vol. c-34, no. 9, Sept. 1985

[2] Gerald Jay Sussman, Jack Wisdom
Numerical Evidence that the Motion of Pluto is Chaotic
MIT AI Lab, AI Memo 1039, April 27, 1988

--
Horace Dediu \"That's the nature of research--you don't know |GTE Laboratories
[phone]\  what in hell you're doing." `Doc' Edgerton  |40 Sylvan Road
UUCP:  ...!harvard!bunny!hhd0................................|Waltham, MA 02254
Internet: [e-mail] or [e-mail]..........|U. S. A.

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

Date: 1 Oct 89 20:51:00 GMT
From: sgi!arisia!cdp![e-mail]
Subject: NSS Hotline Update 9/29/89



This is the National Space Society's Space Hotline updated
Friday, September 29th.

Anti-nuclear activists have filed a lawsuit in Federal District
Court in the District of Columbia in the first ever attempt to
halt a manned NASA shuttle launch. The Christic Institute, the
Florida Coalition for Peace and Justice, and the Foundation on
Economic Trends held a press conference yesterday in Washington
to announce the action. The suit charges that NASA, DOE and the
White House have suppressed vital information on the danger of a
plutonium release during launch. The New York Times quotes NASA
officials as saying the agency's lawyers called the charge
"totally inaccurate and untrue". An official NSS response to the
whole RTG question is under review and will be available to
members, chapters and the public in a matter of days.

The Koopman Express, AMROC's rocket which was due to be launched
from VAFB on Thursday, is still on the pad. Its launch was
scrubbed at T-16 minutes, according to Amroc sources, by AF range
safety because of an inducive lightning condition offshore-
Thursday's weather was cloudy with a light rain.  No new date or
time has been set for launch.

The full Senate yesterday passed the FY 1990 VA, HUD-IA
appropriations bill, including $12.557 billion for NASA's total
budget and $1.85 billion for the Space Station. The bill was
passed by a 92-8 vote. NASA's next budget hurdle will be a
House/Senate conference committee which should take place in the
next few weeks. The entire NASA budget, as well as all other
federal programs other than benefit entitlements will be cut by a
.43 percent across-the-board to pay for the president's drug
eradication program. This cut amounts to some $50 million
dollars.

An article in the Sept. 28th New York Times details Soviet launch
facilities as being open to members of the Moscow foreign press
corps. These are the same facilities which will be open to tours
conducted by NSS member Art Dula's Space Commerce Corp. The SCC
has an agreement with the Soviets to allow private citizen's from
the west to see Soviet space facilities.

The article also discusses disasters which have occured at the
Plesetsk Space Center. The explosion of a Vostok rocket on March
18, 1980 took the lives of 50 Soviet technicians, most of them
military personel. This was previously unknown in the west.

The paper quotes Sovietologist Nicolas Johnson as saying that by
1987, the number of launches from Plesetsk had reached 1,159 -
more than all American, European, Japanese and Chinese space
launches combined.

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

Date: 2 Oct 89 17:47:10 GMT
From: frooz![e-mail]  (Steve Willner)
Subject: Re: power source for the space station

From article <[e-mail]>, by [e-mail] (Greg Wilkins):
> Has solar-thermo-couple power been considered,  ie a solar collector
> focused on one end of a bank of thermocouples???   Is this an improvement
> on solar panels in any shape or form??.

Several others have noted the low efficiency of thermocouples and
rejected this idea.  That was my initial reaction too - certainly right
for space station and other missions where the technology has to be
chosen now -  but I'm not sure it's the final answer.

The problem is that thermocouples used in space up till now operate at
relatively low temperatures and thus have low thermodynamic
efficiencies.  If thermocouples could be designed to operate at, say,
1000 kelvins, the efficiency could be much higher.  New technology
would probably be needed, though, and would have to include a light-
weight collector in addition to the thermocouples.

The principle alternative to using thermocouples at the focus of a
collector is to use a heat engine and a generator.  These have moving
parts, a disadvantage, but the combination is in fact being developed
for possible use in future missions.  I would have thought
high-temperature thermocouple development would be attractive as part
of this program, but there might be some fundamental difficulty with
thermocouple technology that I am not aware of.
-------------------------------------------------------------------------
Steve Willner            Phone [phone]         Bitnet:   willner@cfa
60 Garden St.            FTS:      830-7123           UUCP:   willner@cfa
Cambridge, MA 02138 USA                 Internet: [e-mail]

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

Date: 2 Oct 89 19:09:39 GMT
From: gem.mps.ohio-state.edu!uakari.primate.wisc.edu!aplcen!jhunix![e-mail]  (Ta06)
Subject: Re: Human contamination?

In article <[e-mail]> [e-mail] (Gerald Olchowy) writes:
>Perhaps we are genetically programmed to contaminate the universe.
>The earth, as we all know, has a finite lifetime.  In order for
>the DNA-based life on this planet to survive, it must ultimately
>leave for space.  Perhaps this is why self-conscious intelligent
>creatures evolved on this planet.  ...

This is a misunderstanding of evolution.  Things don't evolve "for" some
future purpose which has not come into effect yet.

The only way evolution could directly produce organisms evolved to conquer
space, would be if in the past there were some organisms more capable of
conquering space than others, thus causing these organisms to be selected for
in preference to other organisms not capable of conquering space.

The capability of conquering space was exactly zero for all organisms in the
past (discounting bacteria and the like, since we're talking about human
beings), so no organism could be selected for as being "better" at conquering
space, since being "better" would give no immediate benefit to the organism.
--
"The workers ceased to be afraid of the bosses.  It's as if they suddenly
 threw off their chains." -- a Soviet journalist, about the Donruss coal strike

Kenneth Arromdee (UUCP: ....!jhunix!arromdee; BITNET: arromdee@jhuvm;
     INTERNET: [e-mail])

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

Date: 2 Oct 89 15:42:33 GMT
From: mailrus!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Concorde, NASP, shuttles

In article <[e-mail]> [e-mail] (daniel mocsny) writes:
>For the business(wo)man to have to travel at all is archaic and
>ridiculous, when (s)he is transacting only information. The time has
>come for us to abandon our obsolete 1950's-vintage thinking...

Abandoning technology is easy; abandoning old ways of thinking is very
difficult.  Especially for businessmen. :-)

>For the cost of developing an aero/space plane, we could instead
>build communication devices that would bring us closer to the
>ulimate goal of saturating the human sensory bandwidth.

We will anyway, so this is fairly irrelevant to the cost of the aerospace
plane.
--
"Where is D.D. Harriman now,   |     Henry Spencer at U of Toronto Zoology
when we really *need* him?"    | uunet!attcan!utzoo!henry [e-mail]

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

Date: 2 Oct 89 16:54:26 GMT
From: mailrus!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Human contamination?

In article <Added.gZ9dE=[e-mail]> [e-mail] writes:
>       ...  Earth life *IS*
>contamination, everywhere but on the Earth.  The other planets are Pristine,
>in that they have developed naturally, possibly independantly...
> Just because we like destroying our own world, does not give us the right
>to spread our short-sightedness to other worlds...

The same comments apply, of course, to mankind's spread outward from Africa,
the colonization of dry land by plants and then animals, and the incredible
ecological catastrophe that ensued when the first algae began releasing
oxygen into Earth's atmosphere.

The other planets, by and large, are not Pristine, but Desolate.  Like the
Hawaiian islands were when volcanic activity first raised them above the
ocean surface.  Hawaii is a fairly nice place now, because life moved in
and reworked the islands to suit itself.  I don't see why it is right
and proper for Nature to do this, yet wrong and evil for Man to do similar
things.  Nature is blind; we are merely shortsighted.  That's an improvement,
folks.
--
"Where is D.D. Harriman now,   |     Henry Spencer at U of Toronto Zoology
when we really *need* him?"    | uunet!attcan!utzoo!henry [e-mail]

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

Date: 3 Oct 89 04:24:26 GMT
From: uceng![e-mail]  (daniel mocsny)
Subject: Re: Concorde, NASP, shuttles

In article <[e-mail]>, [e-mail] (Henry Spencer) writes:
> In article <[e-mail]> [e-mail] (daniel mocsny) writes:
> >For the cost of developing an aero/space plane, we could instead
> >build communication devices that would bring us closer to the
> >ulimate goal of saturating the human sensory bandwidth.
>
> We will anyway, so this is fairly irrelevant to the cost of the aerospace
> plane.

And of course, one could always point out that building an
aerospace plane may *require* funding research to improve the
information technologies. :-)

If the technological challenge of building an aerospace plane
stimulates improvements in our ability to process information, that
will indirectly yield much greater value than the direct "benefit" of
carting a bunch of computerphobic businesscritters around a little
faster. Because eventually our Information Power could increase to
where small groups of private individuals become as productive as
today's large corporation. That would liberate space enthusiasts from
propitiating the public and groveling for government largesse.

Dan Mocsny
[e-mail]

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

Date: 29 Sep 89 02:04:45 GMT
From: ccncsu![e-mail]  (USENET news)
Subject: Re: NASA Headline News for 09/27/89 (Forwarded)

>nation's universities to stimulate so called "cottage industry"
>space research by professors and entice more students to
>specialize in science and engineering studies.  Seven
>universities that participated in a pilot phase of the program at
>Marshall Space Flight Center gave it very high marks.
From: [e-mail] (michael vincen conca)
Path: handel.CS.ColoState.Edu!conca

     Does anyone know how one can gain access to this database? Is it
available on the net in some form?

==========================================================================
              Mike Conca
              [e-mail]
              conca@129.82.102.32
==========================================================================

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

Date: 3 Oct 89 00:07:41 GMT
From: rochester![e-mail]  (Paul Dietz)
Subject: Re: Toxic materials on the Shuttle

In article <[e-mail]> [e-mail] (Henry Spencer) writes:

>Please cite numbers for this, remembering that Pu-238 is an alpha emitter
>which produces very little penetrating radioactivity.  In any case, even
>with the much nastier Pu-239, the stuff is just not all that dangerous
>unless it is finely divided and dispersed.

Well, gram for gram Pu-238 is much nastier than Pu-239.  The gamma
emission from either is not terribly dangerous, and Pu-238 has a much
shorter halflife (so it has many more decays per gram per second).

It would be interesting to compare the activity of the radon daughters
in the air over the US vs. the activity of the Pu-238 in the RTGs.

    Paul F. Dietz
    [e-mail]

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

Date: 2 Oct 89 14:34:41 GMT
From: shlump.nac.dec.com!arkham.enet.dec.com![e-mail]  (Mike Doody)
Subject: Re: Trying to build a fluxgate magnetometer -- help!

In article <[e-mail]>, [e-mail] (Mark A. Haun) writes...
>
>I am trying to build a fluxgate magnetometer sensitive enough to
>monitor variations in the Earth's magnetic field, mostly to observe
>magnetic storms caused by big flares on the sun (March 13, 1989
>stuff especially :-) !).
>

    Have you seen this month's issue of Sky and Telescope magazine?
    There is an article describing just what you want....


Mike Doody                                    [e-mail]
Any opinions expressed are mine and mine alone...

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

Date: 2 Oct 89 16:33:53 GMT
From: mailrus!jarvis.csri.toronto.edu!utgpu![e-mail]  (Gerald Olchowy)
Subject: Re: Human contamination?


Perhaps we are genetically programmed to contaminate the universe.
The earth, as we all know, has a finite lifetime.  In order for
the DNA-based life on this planet to survive, it must ultimately
leave for space.  Perhaps this is why self-conscious intelligent
creatures evolved on this planet.  The dinosaurs roamed this
planet for a lot longer than man, but they vulnerable to an
ecological catastrophe...an encounter with a massive meteor (perhaps!).
Perhaps intelligence became favored in evolution, because it is
it is evolution's current attempt to insure survival of DNA-based
life, by contaminating the universe with it.  It then sort of
becomes survival of the fittest or natural selection whether
Earth-based life can compete with possible other forms of life
in the universe.  Natural selection has worked pretty well on
earth for a few billion years...why shouldn't the same apply
for the universe.

Gerald Olchowy
Department of Chemistry
University of Toronto

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

End of SPACE Digest V10 #112
*******************