Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_3/V13_366.TXT

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Subject: SPACE Digest V13 #366

SPACE Digest                                     Volume 13 : Issue 366

Today's Topics:
   New Improved Rail-Gun, now with Hotol for Added Pep and Verve...
              Re: How 'bout them Titans?
         Re: NY Times Article: Nuclear rocket
                Re: Space Junk
             Re: Space technology
           Re: Advancing Launch Technology
               Laser launchers
              Re: Railguns, EM launchers
           Re: space news from Feb 18 AW&ST
            SPACE Digest V13 #364
        Re: comsat cancellations and lawsuits
              Re: News from Spaceflight

Administrivia:

    Submissions to the SPACE Digest/sci.space should be mailed to
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----------------------------------------------------------------------

Date: Thu,  4 APR 91 10:24:13 GMT
From: [e-mail]
Subject: New Improved Rail-Gun, now with Hotol for Added Pep and Verve...

> Use a short rail, with moderate acceleration to put a fully-loaded, already-
> been-tested-and-budget-approved chemical rocket moving up at around, say,
> 300mph, then fire the rockets.
[...]
> Now, combine that with the HOTOL concept, saving all the weight of the O2, the
> heaviest part of the fuel anyway, for a payload savings around, say, 90%.
[...]
> Tommy Mac  18084tm@msu

Ignoring, for a moment, the difficulties of building and using a rail-gun
capable of lobbing something as massive as a Hotol, why would this save the
weight of the O2? Surely it would only reduce the amount of H2 used, as
Hotol breathes air while it can? That doesn't necessarily mean you couldn't
achieve savings, as the H2 tanking must weigh a lot. I don't know how much
it uses to get to 300mph, but at a guess not as much as a conventional rocket
because it doesn't have to support its entire weight on a plume (wings!)

Out of interest, what size of craft (shell/bullet/blob) are rail-guns being
designed for firing? What's the chance of being able to track them accurately
enough to combine rail & laser/ice propulsion?
_________________________________________________________________
Mike Salmon, Climatic Research Unit    | "Spin, spin, spin the
Univ. of East Anglia, Norwich, England |  Wheel of Justice..."
[e-mail]   [phone] |

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

Date: 4 Apr 91 16:23:23 GMT
From: skipper![e-mail]  (Mary Shafer)
Subject: Re: How 'bout them Titans?

In article <[e-mail]> [e-mail] (Graham Murphy) writes:

   I'd be interested in knowing where the sound track for CNN's
   footage of the explosion came from---presumably not the control
   room.  Shortly after the Titan was destroyed, one hears a voice in
   the background say, "Is it supposed to do that?"  followed by
   another voice giving a very emphatic "No!"

From the media.  CNN et al. were out at the press site to cover the
burn and they picked up what the other crews around them said.

I actually think they were just inside the PIRA (precision impact
range area--bombing range to real people) on the west range.  I
was out there in the PIRA a few months ago and that's what it looked
like to me.  (I've got a project that we're putting in the East Range,
as soon as the EIS and archeology people get done.)

It's not uncommon for the press to be invited to these events.  We
have them at Dryden for such unspectacular things as first flights
and they come out in hordes for anything that would provide a nice
film clip.  Pegasus, Titan burns, etc.

A little more background--when I first moved to Lancaster in 61 they
were doing a lot of rocket burns at the Rocket Site (now the
Astronautics Lab), in support of Apollo, etc.  They'd fire them at
night and you could see them in Lancaster.  A long silent burn and
then, just before the burn ended, the sound would finally make it into
town.  Beautiful, just beautiful.  I don't remember anything blowing
up then, but I'm not sure I'd have noticed unless I saw it.
--
Mary Shafer  [e-mail]  ames!skipper.dfrf.nasa.gov!shafer
           NASA Ames Dryden Flight Research Facility, Edwards, CA
                     Of course I don't speak for NASA
 "A MiG at your six is better than no MiG at all"--Unknown US fighter pilot

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

Date: 4 Apr 91 20:13:35 GMT
From: rochester!sol![e-mail]  (Brian Yamauchi)
Subject: Re: NY Times Article: Nuclear rocket

In article <[e-mail]> [e-mail] (Bob Pendleton) writes:
>Personally I'm glad to hear that they are developing the pellet bed
>reactor for propulsion applications. BUT, I'm very distressed to hear
>that they were looking at using it inside the atmosphere.

According to the UPI article, Timberwind will use a conventional first
stage -- the nuclear stage will not fire until AFTER the rocket leaves
the atmosphere.

--
_______________________________________________________________________________

Brian Yamauchi                University of Rochester
[e-mail]        Department of Computer Science
_______________________________________________________________________________

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

Date: 1 Apr 91 22:53:35 GMT
From: agate!bionet!uwm.edu!rpi!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!pitt!nss![e-mail]  (Paul Blase)
Subject: Re: Space Junk

to: [e-mail]

 S> I am interested in obtain information on a project based at the
 S> University of Arizona named the 'Space Janitor' (a spacecraft
 S> designed to trash unwanted satellites in LEO).
 S>
 S> Any references to space junk in general would also be
 S> appreciated (particularly references to any discussions that
 S> took place on this list in the past).

Check out the Analog article quoted in my other posting on the subject.  It
has a rather complete biblography and some suggestions for a 'space janitor'

--- via Silver Xpress V2.26 [NR]
--
Paul Blase - via FidoNet node 1:129/104
UUCP: ...!pitt!nss!Paul.Blase
INTERNET: [e-mail]

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

Date: 5 Apr 91 05:09:30 GMT
From: unmvax!uokmax![e-mail]  (Robert W Murphree)
Subject: Re: Space technology

Actually, I like to think of the word "spinoff" as one of the great
PR triumphs of the 60's-basically its a publicity hoax invented to
quiet disturbed tax payers like your father.  Carl Sagan is fond of
saying that in matters of applied research, if the object is a no-stick
frying pan, you're almost always better off backing research into no-
stick frying pans rather than laser-guided tennis balls.
The major technologies of importance from space are (in order of
importance) ICBM's, military reconnaisance satellites, weather, and
communication satellites, astronomy and planetary science probes.

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

Date: 5 Apr 91 06:24:24 GMT
From: sdd.hp.com!cs.utexas.edu!sun-barr!newstop!exodus!norge.Eng.Sun.COM![e-mail]  (John McKernan)
Subject: Re: Advancing Launch Technology

[e-mail] (Nick Szabo) writes:
>In article <[e-mail]> [e-mail] (Walt Leipold) writes:
>>For
>>the sake of discussion, let's assume a modest 500g acceleration in a purely
>>horizontal launcher....
>We can actually get much more than this right now in the lab, but
>perhaps this is a good number for a system with low materials
>costs.

I don't think a 500g or greater acceleration EM launching device would replace
chemically powered launchers. It might be useful for launching bulk materials,
but it can't launch large complex systems like space stations, the Earth
observation system, Gallileo, human beings, etc. So even if we had an
EM launcher, we would still need chemically powered launchers.

It does seem possible to replace chemical launchers with a laser powered
launch system, but not for at least 15 or 20 years. The technology to
generate and maintain a beam of sufficient energy for the required length of time, and then focus and aim it simply doesn't exist. There
has been a lot of research on lasers, but there is still a LONG way to
go before we get to the level of technology we need.

Since we're stuck with chemically powered launchers for at least the
next 15 or 20 years, it makes a lot of sense to try and reduce their
cost by an order of magnitude or so. And Nick, you can repeat yourself
until you're blue in the face, but it's just a fact that with such a
small number of complete chemical launcher design iterations, we just
DON'T KNOW what the lowest possible cost of that technology is.

John L. McKernan.                                                  [e-mail]
Disclaimer: These are my opinions but, shockingly enough, not necessarily Sun's
-------------------------------------------------------------------------------
   "It's kind of a macho thing,
    programmers are always trying to be weirder than their machines."

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

Date: 4 Apr 91 11:03:42 GMT
From: eru!hagbard!sunic!mcsun!ukc!slxsys!ibmpcug!demon![e-mail]  (Ian Stirling)
Subject: Laser launchers


>Chem rockets cannot provide even a one order of magnitude drop, but
>tethers combined with suborbital airplane or laser launch, combined
                                              ^^^^^
                                             what is a laser
launcher? I have heard some references to it,Is it using a ground
based laser to heat fuel on-board a vehicle so that the fuel boils
violently,propelling the vehicle.Is this a current technology or does
it still need massive advances in laser technology?

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

Date: 4 Apr 91 16:09:39 GMT
From: udecc.engr.udayton.edu!blackbird.afit.af.mil!lonex.radc.af.mil![e-mail]  (Harold G. Andrews II)
Subject: Re: Railguns, EM launchers

Tom McWilliams writes:
>
>Use a short rail, with moderate acceleration to put a fully-loaded, already-
>been-tested-and-budget-approved chemical rocket moving up at around, say,
>300mph, then fire the rockets.

To which Henry Spencer responds:
>
>Unfortunately, those chemical rockets aren't designed for a horizontal
>takeoff.  You could get useful gains by catapulting them at such speeds
>*vertically*, and in fact there was a recent Japanese proposal to do
>just that.

To which I now ask:
What kinds of problems are the Japanese running into, and what kinds of set-ups
are they looking at?  Are the EM launchers under-ground?  Could you point
me to some articles discussing the Japanese efforts?  Just curious.
Thanks.


-Andy

*******************************************************************************
* Harold G. "Andy" Andrews II             *  "Many the man whose punctuality  *
* [e-mail]              *   serves only to warm his chair." *
* Rome Laboratory/IRRE                    *                                   *
* Griffiss AFB, NY 13441-5700             *   - M. Kabrisky                   *
* [phone]  (AVN Prfx 587)          * (Not an official  USAF viewpoint) *
*******************************************************************************

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

Date: 5 Apr 91 18:05:41 GMT
From: swrinde!elroy.jpl.nasa.gov!sdd.hp.com!spool.mu.edu!snorkelwacker.mit.edu!primerd!primerd![e-mail]
Subject: Re: space news from Feb 18 AW&ST



From Henry's notes of Feb 18 AW&ST:
>[March issue of Spaceflight mentions that astronaut William F. Fisher has
>left NASA to return to medical practice.  No big surprise, on thinking
>about it:  he was co-chair of the group that reported the bad news about
>EVA requirements for Fred, which probably killed his chances of future
>flight assignments.]

Personal comment: This is really sad.  The recent book on Apollo (I forget
whose) lamented the passing of the age within NASA et al where one could
mention something to one's boss.  One could tell the boss something,
just like a colleague, without asking for or receiving a decision.  This
period of "camalot" is now gone.  If the note about Dr. Fisher is true,
things are now much worse.  Things are becomming so political that one can
destroy one's career by succeeding at one's assigned tasks just because it
is politcally unpopular.  Shoot the messenger, perhaps.

Sigh.
Jim Cook
<[e-mail]>

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

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Date:         Fri, 5 Apr 91 02:50:59 EST
Reply-To: [e-mail]
From: [e-mail]
Subject:      SPACE Digest V13 #364
Comments: To: [e-mail]
To: david polito <[e-mail]>, Tom McWilliams <[e-mail]>


>> Use a short rail, with moderate acceleration to put a fully-loaded, already-
>> been-tested-and-budget-approved chemical rocket moving up at around, say,
>> 300mph, then fire the rockets.

>Good Idea.

  (Tom says that since he can think of it, but no-one doing actual launches has
   chemical rockets must not be 'stretched to their technical limits')

>You must not have read the same science fiction I did. Bob Heinlein
>used this idea alot in his stories. I think "Space Cadet" was the
>first place I remember reading about it.

>The "short" rail ran up the west side of Pike's Peak. The rocket
>planes sounded like scaled up X-1s with swept wings. The Great Plains
>served as a great place to ditch if the engines didn't fire.  And, of
>course, being an early Heinlein juvy (don't ever lie to kids!) you can
>bet that there was a solid engineering and mathematical basis for
>believing that it would work.

I'm a fan of his too.  Agreeing with his politics helps.  :-)

>one of the reasons I don't think chemical rockets have topped out is
>that ideas like this one have been around, and practical, since the
>1930s and know one has even tried them.

You said it!

>> P.S> I don't think chemical rockets will ever have a market outside LEO
>>      My personal favorites are the ion rocket and solar sail.

>I agree that chemical rockets haven't much future beyond LEO. But I'm
>rather fond of fission torch rockets myself. I want to get there NOW,
>not next year. :-)

But where can you go?  You certainly won't be using fission in MY back
lagrange point (oops, I mean yard) |-)

Actually, with Ion systems, since the ISP is so high, you can accelerate for
the entire trip.  Toward your destination at first, and slowing down
after the half-way point.  You'll start out at only a few meters/minute, since
the amount of mass is so low.  But after a day you'll be moving 76400 times
faster.  after a week, 534800 times, and after a year, 2.7e+7 times. (.90c)
This is all ignoring relativity, of course.   As an example, at .9c, a trip to
Alpha Cent. would appear (th those on earth) to take 4.4 years.  But you would
feel like it only took about 2.5 years.  That's 2 times the speed of light!

Either way, I hope it happens soon enough for me to see it.

Tommy Mac
18084tm@msu
Acknowledge-To: <18084TM@MSU>

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

Date: 5 Apr 91 20:06:57 GMT
From: swrinde!zaphod.mps.ohio-state.edu!wuarchive!rex!rouge![e-mail]  (Fraering Philip)
Subject: Re: comsat cancellations and lawsuits

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

>Considering passed performances and some questionable over charging, I'm
>not sure that Hughes or any other aerospace firm has a "right" to be ticked
>off.  Call it poetic justice.  This law suit, no matter who wins, is going to
>cost the U.S. taxpayer.  Since Henry is Canadian he doesn't have to worry,
>though. :-)

This is really twisted, when you think about it: "Based on past
wrongs by 'aerospace companies' which may or may not include Hughes
but which the government refused to sue them for breach of contract
(nicely avoiding the question of whether or not the company
itself is guilty; maybe it's guilty just for being a member of
the group of 'aerospace companies') gives the government the right
to abbrogate contracts without penalties."

Come on, if the government thinks something wrong has occured, then
they should fight for their rights, not lie in wait for some company
which may or may not be guilty to trust them and then breach the
contract...

Phil Fraering
[e-mail]

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

Date: 5 Apr 91 20:18:02 GMT
From: deccrl!news.crl.dec.com!shlump.nac.dec.com!ryn.mro4.dec.com!troa09.enet.dec.com![e-mail]  (Susan Klein)
Subject: Re: News from Spaceflight


In article <[e-mail]>, [e-mail] (Mary Shafer) writes...
>In article <[e-mail]>
>[e-mail] (Henry Spencer) writes:
>
>   March issue of Spaceflight mentions that astronaut William F. Fisher has
>   left NASA to return to medical practice.  No big surprise, on thinking
>   about it:  he was co-chair of the group that reported the bad news about
>   EVA requirements for Fred, which probably killed his chances of future
>   flight assignments.
>

Anna Fisher was chosen in August 1978 Group 8 astronaut group. Bill Fisher
was chosen in May 1980 Group 9. Interesting that both have made only 1 flight
so far and the Anna, still an active astronaut, has not made a flight since
STS 51A    in November 1984. Bill's flight was STS 51I August 1985.

Susan Klein    [e-mail]
        --or-- ...!decwrl!troa09.dec.com!sklein
        --or-- [e-mail]

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

End of SPACE Digest V13 #366
*******************