Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v15_1/v15no105.txt

Internet Message Format | 1993-07-13 | 16KB

Date: Thu, 13 Aug 92 05:02:34
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #105
To: Space Digest Readers
Precedence: bulk


Space Digest                Thu, 13 Aug 92       Volume 15 : Issue 105

Today's Topics:
                         beanstalk in Nevada
              Beanstalks in Nevada Sky (was Re: Tethers)
                   Germans drop European Shuttle ?
                          Parsecs? (4 msgs)
                        Request: Sex in Space
                    Solar System Journal (2 msgs)
             SPS feasibility (WAS: SPS fouling astronomy)

    Welcome to the Space Digest!!  Please send your messages to
    "[e-mail]", and (un)subscription requests of the form
    "Subscribe Space <your name>" to one of these addresses: listserv@uga
    (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle
    (THENET), or [e-mail] (Internet).
----------------------------------------------------------------------

Date: Wed, 12 Aug 92 18:58:25 PDT
From: [e-mail]
Subject: beanstalk in Nevada
Newsgroups: sci.space

"I would suggest you drop the word orbit. There is no possible orbit
that can put a satellite continuously over Nevada. None. Period.

The only possibilities are solar sails and maglev devices that sit at
least several thousand miles up. They would not be in free fall, they
would be using an energy source to counter the acceleration due to
Earth's gravity at that altitude."

O.K.  How much energy would it take to keep a casino hovering over
Nevada at a height of 200 miles?  Would there be any unusual stresses
on the tether because the casino is hovering over Nevada?

                                                           Eric Klien.

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

Date: 12 Aug 92 17:44:54 GMT
From: "Michael K. Heney" <[e-mail]>
Subject: Beanstalks in Nevada Sky (was Re: Tethers)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Dave Jones) writes:
>
> [...]
>
>Clarke also had his tower made of that famous variety of unobtainium,
>monomolecular filament.  Assuming he'd done some basic estimates, you
>have to figure that's the kind of tensile strength you need for a cable
>23,000 miles long.  He also had a captured asteroid stuck out on the
>far end as a counter-weight, possibly at a height beyond GEO.
>

Don't forget the _2061: Odyssey Three_ approach - diamond.  I know diamond
is used in presses to generate pressures in the millions of atmospheres
(in very *small* volumes), but is it actually strong enough to handle the
tensile forces a GEO-centered tether would need to handle?

Also, given a properly counterweighted system, so that the cm (or is it
cg?) is at GEO, and the bottom of the tower nuzzles gently on the ground,
wouldn't orbital perturbations really mess things up in a hurry?  Given
the masses we're talking about, stationkeeping would be quite a problem,
no?


Mike Heney               | Looking for Senior level technical | Reach for the
[e-mail]  | and administrative positions world | Stars!!!
Kensington, MD (near DC) | wide.  Call me.                    |

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

Date: 12 Aug 92 10:38:46 GMT
From: [e-mail]
Subject: Germans drop European Shuttle ?
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Phil G. Fraering) writes:
> <[e-mail]> writes:
>
>>Whilst skimming thru the TV channels last week, I caught sight of the
>>German research minister, Riesenhuber, saying that Hermes was 'unacceptable'
>>(not exact translation) to the German government in either manned or unmanned
>>form. Two days later he showed up at the European Space Operations Centre to
>>congratulate senior management on the fine job they'd done on Eureca. I'm
>>cynical enough to believe that when politicians start throwing praise around,
>>one should watch one's back. The ESA ministerial conference in November will
>>probably contain some nasty surprises.........
>
> Hey! He's probably just tired of the way the French have shut down all
> launch vehicle research besides Hermes/Ariane V in ESA...
>
> To wit, Saenger and Hotol...

HOTOL and, as far as I know, Sanger were never properly adopted ESA projects.
They were national or corproate schemes proposed to ESA as possible future
launchers, which ESA didn't take up (mores the pitty).

Sanger, I think, died there and then, but HOTOL continued as a British
Aerospace project, though they had to drop Alan Bond's air breathing rocket
motors since Rolls Royce, who owned the patent, refused to do anything without
government/ESA support. Thus was born the Interim HOTOL, which would use a
modified HOTOL airframe with conventional motors, lifted to altitude by an
Antonov 225 (the plane tht carries bits of Energia around) also modified to
give it extra thrust (extra engines added). This project was in conjunction
with the USSR/CIS/whatever.

Now, though, British Aerospace have closed down their Space Systems division in
Stevenage, where the project was based, and so this scheme too would appear to
have died.

And thats the way the British 'space industry' operates.

--
================================================================================
Dave Clements, Oxford University Astrophysics Department
================================================================================
clements @ uk.ac.ox.vax            |  Umberto Eco is the *real* Comte de
dlc      @ uk.ac.ox.astro        |           Saint Germain...
================================================================================

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

Date: Wed, 12 Aug 92 23:51:12 GMT
From: Daniel Briggs <[e-mail]>
Subject: Parsecs?
Newsgroups: sci.space

In article <[e-mail]>
>The definition of a parsec is the distance at which the PARallax of an object
>(star, galaxy, what have you) is one SECond.  This distance is about 3.21
                                      ^^^^^^
>light years if I remember correctly (Don't have any books near me to check
>this).  Hope this is helpful.

arcSECond, please.  Astronomy uses both time seconds and arcseconds.  It's a
bad habit to get into to use 'second' for both.  Many an observation has
gone down the tubes because these units were inadvertantly mixed up.  Even
the pros do it, if they are not careful.

BTW, it's 3.26 light years to the parsec.  You were pretty close.

--
| Daniel Briggs  ([e-mail])                      |        USPA B-14993
| New Mexico Tech / National Radio Astronomy Observatory |            DoD #387
| P.O. Box O / Socorro, NM 87801   [phone]        |
Support the League for Programming Freedom  (info from [e-mail])

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

Date: 13 Aug 92 02:55:41 GMT
From: Jim Carr <[e-mail]>
Subject: Parsecs?
Newsgroups: sci.space,sci.physics

In article <[e-mail]> [e-mail] (Craig "Powderkeg" DeForest) writes:
>
>This talk of parsecs and so forth reminds me of my favorite volumetric unit:
>the barn megaparsec.
>
>A barn is a unit of atomic cross-section, 10^-20 cm^2.  A barn megaparsec is
>about 1.6 teaspoons!

Cute, but I have always preferred the Hubble-barn.  Granted, the exact
value of the Hubble constant is not exactly agreed upon, but I like
the fact that if you multiply the size of the universe (one uses the
Hubble length, obviously) by 1 barn you get something like 16 liters.

(I used to have a gallon milk jug that I used for watering plants that
had a mark at the 0.1 Hubble-barn level.  Very convenient.)

My notes are scribbled in the back of "Gravitation", which is at work,
but memory says that a Hubble-barn is the volume of a straw that has an
opening the size of the nucleus of silver and reaches to the edge of
the universe.  BTW, a barn is 10^{-24} cm^2 -- 1 fm^2 = 10 mb.

--
J. A. Carr                                    |  "The New Frontier of which I
[e-mail]                           |  speak is not a set of promises
Florida State University  B-186               |  -- it is a set of challenges."
Supercomputer Computations Research Institute |   John F. Kennedy (15 July 60)

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

Date: 13 Aug 92 03:06:30 GMT
From: Keith Allan Schneider <[e-mail]>
Subject: Parsecs?
Newsgroups: sci.space,sci.physics

[e-mail] (Craig "Powderkeg" DeForest) writes:

>[e-mail] (Arlin B. Collins) writes:
>   (Brian Kemper) writes:
>   > (Richard Martin) writes:
>   > > Please forgive my ignorance, but what the heck is a parsec?
>   > I know a parsec is a unit of distance equal to roughly 3 light-years ...
>   One parsec equals  30.857x10**12 km, 206265 astronomical units, and
>   3.2616 light-years.

Hmmm...  at the distance of one parsec, one astronomical unit subtends an
angle of one arc second.

keith

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

Date: 12 Aug 92 17:40:29 GMT
From: Ron Echeverri <[e-mail]>
Subject: Parsecs?
Newsgroups: sci.space,sci.physics

In article <[e-mail]> [e-mail] (Keith Allan Schneider) writes:
>Hmmm...  at the distance of one parsec, one astronomical unit subtends an
>angle of one arc second.

Coincidence.  Remember, one AU is the distance from the Earth to the Sun...

5150
look ma, i can nitpick too! :)

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

Date: 12 Aug 92 19:07:48 GMT
From: "C.E. Johnson " <[e-mail]>
Subject: Request: Sex in Space
Newsgroups: sci.space

There was an article posted a few years ago dealing with experiments
on sex in space.  If anyone has a copy of this, please forward it to
my address.

--
Carl E. Johnson                        'Tis not the drinking that is
Rochester Institute of Technology       to be blamed, but the excess.
[e-mail]                                   - John Selden

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

Date: 13 Aug 92 02:28:44 GMT
From: Robert W Murphree <[e-mail]>
Subject: Solar System Journal
Newsgroups: sci.space

ADDENDUM

GIOCOBBI-ZINNER

memorable pictures: none, only particles and fields experiments

This was one of the few examples of piracy by one member of the
space community by another that I can recall.  The spacecraft
was launched as a solar wind monitoring craft and was never
designed for comet encounters.  When NASA decided to reassign it
to comet encounter duty, it was over protests by some team members
who lost their experiments.  It really appears that number one)

   1) NASA had realized they were going to lose international
prestige by not joining the international flotilla of Halley
encounter spacecraft (Europe, Soviets, and Japanese).

What to DO?

    2) send one of their own craft to make a first encounter
with a comet, albeit, a one very poorly designed for such an
encounter, and claim a PR victory by making their encounter
before the Halley flotilla arrived at Halley. hence the
Giocobbi-Zinner encounter.

The other example of space piracy?  A perfectly healthy
working earth orbiting satellite that was shot down to
test and probably also give PR boosts to SDIO, 4-5 years
ago.  You can bet the scientific investigators were mad
about that one as well.

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

Date: 13 Aug 92 04:34:09 GMT
From: Henry Spencer <[e-mail]>
Subject: Solar System Journal
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Robert W Murphree) writes:
>    2) send one of their own craft to make a first encounter
>with a comet, albeit, a one very poorly designed for such an
>encounter, and claim a PR victory ...

Actually, ISEE-3 was a fields-and-particles monitoring satellite, and
not that ill-suited to a comet encounter.  A custom-designed bird would
have been a lot better, of course... but note that Giotto, custom-built
for the job, is likewise mostly fields-and-particles experiments.

>The other example of space piracy?  A perfectly healthy
>working earth orbiting satellite that was shot down to
>test and probably also give PR boosts to SDIO...

A perfectly healthy working satellite *built and owned by the Defense
Department* that the legitimate owner decided to sacrifice to an
antisatellite test (run by the USAF, not SDIO -- SDIO doesn't do
antisatellite weapons, although they doubtless were keenly interested
in the test).

Yes, there were scientific experiments aboard, still yielding useful
data, whose investigators were miffed about it.  But there was no
question of "piracy"; the satellite's owners merely decided that it
had served its primary purpose and was expendable in what they saw
as a worthy cause.  This may have been a poor decision, but it *was*
theirs to make.
--
There is nothing wrong with making      | Henry Spencer @ U of Toronto Zoology
mistakes, but... make *new* ones. -D.Sim|  [e-mail]  utzoo!henry

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

Date: 12 Aug 92 20:49:39 GMT
From: Nick Szabo <[e-mail]>
Subject: SPS feasibility (WAS: SPS fouling astronomy)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:

>The cost is covered during a general buildup of lunar resource development
>Reference the Lunar materials development papers of the last few years for
>numbers.  A very up to date set is from the ASCE Space 92 conference June 1-5
>1992 in Denver CO.  Look Especially for Dr. Criswell's papers on the subject.

Dr. Criswell makes his numbers up out of the thin blue air, especially the
mass ratios for his fictional industrial processes.  In many cases he
assumes several orders of magntitude improvement over current industrial
processes, and ignores large industrial inputs like air and water,
without explanation.  He is an utter fraud, and his fantasy (it's not
even good science fiction) is highly destructive to the space
colonization movement.

>No but converting a transportation infrastructure that runs on billions of
>gallons on Hydrocarbons per year to one of running on Terawatts of electricity
>will require a vast increase in electrical production.

You don't need to convince us about this. You need to convince the baby
boomers running the electrical utilities that it takes more than
"conservation" to power the world.

>This is a flame and meant to be a flame.

No, Fred's article was meant to introduce some reality into your
thick-headed but narrow-minded skull.  _This_ is a flame.

>The Rio summit endorsed only ONE space technology and that was laser
>power beaming from the moon.

Which part of the "Rio summit"?.  BTW, they also endorsed environmental
monitoring from space, $100's of billions of give aways from the U.S. to
3rd world countries, and "sustainable development", for what it's worth.
No major corporations and no politician beyond Al Gore take Rio seriously.
Nobody with influence in industry takes Criswell seriously.

>The SPS will help those who want to be helped.

Pointing out the facts about SPS will help those who want to
know the truth, and find out the best way to do things, but it won't
do much for idiots who treat technology like religion. Your arguments
sound far more like a Medieval bishop fighting heresy than a
scientist searching for the truth or an engineer for the best solution.



--
[e-mail]  Public Access User --- Not affiliated with TECHbooks
Public Access UNIX and Internet at [phone] (1200/2400, N81)

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

End of Space Digest Volume 15 : Issue 105
------------------------------