Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V11_1/V11_118.TXT

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Subject: SPACE Digest V11 #118

SPACE Digest                                     Volume 11 : Issue 118

Today's Topics:
                  sci.astro
               Re: More info on Pegasus
           Re: NORAD to AMSAT Quick Track ?
          Re: Spacecraft drives and fuel efficiency
              Re: Space tomatoes
      Re: Fun Space Fact #1: Launcher Development Costs
                 Rocket Info
----------------------------------------------------------------------

Date:     Mon, 05 Mar 1990 16:03 EST
From: DAVID SIMMONS <[e-mail]>
Subject:  sci.astro
To: <[e-mail]>

     sci.astro is a newsgroup on USENET. Is it available in Digest form

and how do join it?

     David Simmons

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

Date: 6 Mar 90 01:33:34 GMT
From: mailrus!jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: More info on Pegasus

In article <[e-mail]> [e-mail] writes:
>...The article also called Pegasus
>the first new launch vehicle in the U.S. inventory since the Shuttle.
>Is this true?

Unless you have a rather loose definition of "new", yes.  (E.g. Titan IV
is a slightly souped-up Titan III with longer SRBs, not a "new launcher"
by most reasonable definitions.)

>Also, what is the payload size of Pegasus, and how high can it
>propel its payload? Will Pegasus ever carry commercial satelites?

Payload size is somewhat under 1000 lbs, as I recall; I can probably dig
up a more precise number if it's needed (and nobody beats me to it).  It
is strictly a low-orbit launcher, although one could always add a (small)
upper stage to propel a (small) payload higher, and at least one customer
(Ball) is talking about this already.  The odds of Pegasus getting
commercial business approach 100%, barring a nasty failure or something
like that.

>Is Pegasus something to get excited about?

Yes.  Even if OSC goes bankrupt after launching one payload -- which does
not seem likely! -- it will prove that you don't need ten years and a
billion dollars to develop a new launcher.  Proof of this is sorely
needed; people from certain government agencies claiming to be experts
on rocketry will firmly assure you that you *do* need decades and
billions, and this has been a serious obstacle to private launcher
development.
--
MSDOS, abbrev:  Maybe SomeDay |     Henry Spencer at U of Toronto Zoology
an Operating System.          | uunet!attcan!utzoo!henry [e-mail]

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

Date: 5 Mar 90 16:43:55 GMT
From: idacrd![e-mail]  (Robert McGwier)
Subject: Re: NORAD to AMSAT Quick Track ?

From article <[e-mail]>, by [e-mail] (Mike Peyton):
>
>  Does anyone have a way to convert the NASA/NORAD Prediction Bulletins directly
> to the N4HY's AMSAT Quick Track KEPC.DAT file? It get's old putting all those
> numbers by hand.......
>


Mike:

That is ANCIENT technology. QT 4.0a has an automatic element loader.
Contact the AMSAT office for update policy.

Bob
N4HY

--
____________________________________________________________________________
    My opinions are my own no matter    |    Robert W. McGwier, N4HY
    who I work for! ;-)            |    CCR, AMSAT, etc.
----------------------------------------------------------------------------

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

Date: 6 Mar 90 00:40:06 GMT
From: zaphod.mps.ohio-state.edu!samsung!cs.utexas.edu!jarvis.csri.toronto.edu!helios.physics.utoronto.ca!physics.utoronto.ca![e-mail]  (Christopher Neufeld)
Subject: Re: Spacecraft drives and fuel efficiency

In article <[e-mail]> [e-mail] (Tim Maroney) writes:
>>In article <[e-mail]> [e-mail] (Tim Maroney) writes:
>In article <[e-mail]>
>[e-mail] (Christopher Neufeld) writes:

>>   I think a NASA study showed something like 1mg to launch the shuttle
>>using a reaction mass tank such as I described above.
>
>Of course, it would be carrying more if it wanted to go somewhere in
>the solar system.  Forward vagues out on the figures, but he indicates
>that grams are necessary for manned interplanetary spacecraft.
>
   Yes, but I really can't imagine interplanetary spacecraft being launched
from the ground.

>In ordinary use, antimatter spacecraft would probably create a lot of
>mutations in the area immediately surrounding the landing site, which
>would doubtless have a long-term effect on the area's environment, but
>probably would not have any wider effect.
>
   The effect would be to increase the rate of mutations, and probably of
evolution. Most mutations are fatal, so this would probably kill things in
the area, but only nearby. Remember that the engine I described gets most
of its energy from absorption of gamma rays by the reaction fluid, so gamma
ray leakage is an inefficiency. Because of the shielding effects of the
reaction fluid (which must be a good shielding material if it is to work in
this configuration), leakage should be primarily straight down, where
mutations are the least of your concerns. You're right, though, that this
would not be prime real estate because of the likely measurable radiation
every time a ship launched.
   I don't think that radiation would be as damaging to the environment as
the construction of the space port in the first place (things don't grow
well in cement).

>However, if a few grams of
>antimatter explode near the ground or higher up, then the consequences
>are plainly more severe than the detonation of a chemical rocket.
>Radiation would be spread over a wide area as from a nuclear blast, and
>even though (as you point out) it is only ionizing radiation, not
>activating radiation, the consequences would be felt over a wide area
>and over a long time.  Increased cancer rates and EMP are very likely
>consequences.
>
   Yes, but that represents the fuel requirement of hundreds or thousands
of shuttle launches (using shuttle in the generic sense, not necessarily
the ones flying now).

>I still think the best course is probably to build the ships in space,
>and manufacture the antimatter in space as well.  Interplanetary
>spacecraft will probably benefit economically from not having to cope
>with atmospheric conditions in any case; the safety consequences are
>just gravy.
>
   I quite agree. Antimatter manufacturing is probably more likely in
space, in powersats or on the moon. Interplanetary spacecraft almost
certainly would not be capable of landing on anything bigger than a small
asteroid. I think that it is not unlikely, though, that some antimatter
would be returned to Earth to power the shuttles, because it is so
convenient. If every shuttle had its antimatter reservoir topped off before
the glide back to the launch point it would not mean huge quantities of the
dangerous stuff sitting in one place, and in my opinion this would be less
damaging to the environment than preparing a chemical fuel on the ground
for the shuttles (since this requires terrestrial energy sources, none of
which is ideal).

>Tim Maroney, Mac Software Consultant, sun!hoptoad!tim, [e-mail]


--
 Christopher Neufeld....Just a graduate student  | "I always think there's
 [e-mail]              | a band."
 [e-mail]                    |   Prof. Harold Hill
 "Don't edit reality for the sake of simplicity" |   (The Music Man)

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

Date: 5 Mar 90 22:29:44 GMT
From: vsi1!v7fs1![e-mail]  (Mike Van Pelt)
Subject: Re: Space tomatoes

In article <[e-mail]> [e-mail] (John Roberts) writes:
>[12.5 million tomato seeds from LDEF]
>Maybe in a few years, they'll have a new entry in their catalog:
>  "The Triffid Tomato - it walks right into your kitchen!"  :-)

How about...

   (singing)    ATTAAAAAAKKKK of the Killer TomaAAAAAAtooooes!

(I'm surprised this hasn't been brought up before.  After all, these
seeds have been exposed to *RaDiAtIoN* which, as anyone who has watched
any of those bad 50's sigh-fie movies knows, invariably turns harmless
life-forms into giant bloodthirsty mutants.)
--
Mike Van Pelt                     "I'm not a biologist, but I play one in
Headland Technology/Video 7        front of Congressional hearings."
...ames!vsi1!v7fs1!mvp                        -- Meryl Streep

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

Date: Mon, 5 Mar 90 15:04:39 CST
From: [e-mail]
Subject: Re: Fun Space Fact #1: Launcher Development Costs

>> uunet!attcan!utzoo!henry [e-mail]

>> But I don't think the 747's safety margins are much smaller than
>> those of a Cessna; if anything, it has to meet rather tougher
>> standards.

And is the 747 also no more complex than the Cesna?  Complexity is
swapped off with the stress the parts have to take.  That's what
that redesign you say is necessary *does*.

[The 747 also requires significantly more maintenance hours than a
Cesna, I suspect.  Which was my point in the first place.]


==============================================================================
| Fred McCall  ([e-mail]) | My boss doesn't agree with anything  |
| Military Computer Systems           | I say, so I don't think the company  |
| Defense Systems & Electronics Group | does, either.  That must mean I'm    |
| Texas Instruments, Inc.             | stuck with any opinions stated here. |
==============================================================================

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

Date: 5 Mar 90 23:41:48 GMT
From: [e-mail]  (James Kolasa)
Subject: Rocket Info


I'm preparing a simple programming assignment for my students and I wonder
if someone could give me some figures.  Does anyone have a rough estimate of
mass of a rocket (esp. Saturn V)?  How about fuel capacity?  How about
a conversion factor between kilograms of fuel and thrust (in Newtons)?
Any assistance or very rough estimates would be extremely helpful.
Thanx.
                                   jk

--
--   James Kolasa                |      "Computers are so naughty,           --
--   121 Moloney, L.C.C.         |          I could just pinch them"         --
--   Lexington, Ky.  40506-0235  |                   -The Martian            --
--   [e-mail]   {rutgers,uunet}!ukma!jkolasa   [e-mail] --

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

End of SPACE Digest V11 #118
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