Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V11_1/V11_161.TXT

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Subject: SPACE Digest V11 #161

SPACE Digest                                     Volume 11 : Issue 161

Today's Topics:
     Re: Coilgun on a 747 - supplies to orbit at $20/lb?
           Re: Artificial Gravity rephrased
              Re: Challenger last words
     Re: Coilgun on a 747 - supplies to orbit at $20/lb?
        Re: What was Challenger really up to?
      Re: Reliability, Bureaucracy, and Spaceflight Costs (long)
              Gerard K. O'Neill lecture
                   Re: USF
----------------------------------------------------------------------

Date: 16 Mar 90 23:12:07 GMT
From: nuchat![e-mail]  (Steve Nuchia)
Subject: Re: Coilgun on a 747 - supplies to orbit at $20/lb?

In article <[e-mail]> [e-mail] (Vincent Cate) writes:
>Sounds like a coilgun on a high flying 747 should be a cheap way to
...
>What are the hard parts of this type of approach?

My guesses would be recoil and  muzzle aerodynamics.  Some of the momentum of
the aircraft gets transfered to the projectile.  Your projectile mass is
limitted by the need to keep flying.

There is a minimum size payload that will be useful, and multi-shot
groups will be spread out over a whole lot of orbit.  Fuel, for instance,
really wants to be launched in large batches for a decent payload/container
mass ratio and handling costs.

And a 747 really doesn't fly that high.  Maybe you could reengine
one for operation where the air is rare, but in any case you'd start
running out of lift and have to derate your mass calculations.
You could get above a lot of atmosphere but you'd still be shooting
through a lot, and now you'd have it shearing past your muzzle at
450 kts or whatever.

I do know that the energy storage problem has a solution.  A group
at Texas A&M (if memory serves) has a railgun power supply "the
size of a garbage can", using some kind of magnetic/electromechanical
principle.  The primary generators in the engines or your APUs place
one limit on the firing rate, but once you charge the secondary
generator you can pull megawatts out of it for the duration of the
shot.

A 747 is what, 200 ft long?  Calculate the accelleration required
to reach orbital velocity from, say, 1200 kts (air speed plus
rotation, fudged for inclination and wind) in 200 ft.  It won't
be as kind to your payload as a longer ground based gun would
be, but you may make it up in reduced heating for some payloads.

Interesting idea, but I think you need a high-altitude, hypersonic
aircraft for your first stage.  A 747 just isn't enough better than
a ground station to justify the cramped quarters, increased operation
risk, and weight limits.

One advantage it does have over a ground station is the ease with
which it can match launch to window.  Just fly to where the window
is and yank the cord.
--
Steve Nuchia          South Coast Computing Services      [phone]
"You have no scars on your face, and you cannot handle pressure." - Billy Joel

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

Date: 16 Mar 90 23:36:55 GMT
From: nuchat![e-mail]  (Steve Nuchia)
Subject: Re: Artificial Gravity rephrased

In article <[e-mail]> [e-mail] (Perry The Cynic) writes:
>Sure. Let's look at the "natural gravity" counter-experiment: you stand on an
>idealized, spherical earth, and horizontally throw a baseball at circular orbit

>What's really happening of course, in both experiments, is that you make use
>of the local geometry to impose pseudo-forces on your ball.

Uhm, well, the situations are duals of one another.  In the "natural gravity"
case you are using circular motion to cancel gravitational acceleration.  In
the artificial gravity case you are cancelling motion to remove geometric
accelleration.

>And yes, atmospheric drag will get the ball, in either experiment. But that's
>just a minor detail :-)

In the natural case drag will win, because the earth is coupled to the
atmosphere and all moving together.  In the artificial case one could
easily imagine that the squirrel cage was a mere circular catwalk inside
a stationary room.  In that situation the air might be coupled to the
walls better than the floor.  So if you do succeed in momentarily
cancelling the ball's relative motion, the air conditioning system wins.


Somebody mentioned proposed rotating sleep chambers as a counterexample
to the assertion that tidal effects in a small diameter artificial
gravity rig will make you puke.  The answers there are 1) the rig
is proposed, they don't know how well it will work in practice, and
2) If you laid down on the floor of a squirrel cage you probably
wouldn't get sick.  You also wouldn't get much work done.  It's
having your head at a different radius, and therefore acceleration,
(ie, tides) plus corlais (sp?) effects (which happen when you move)
that get you.
--
Steve Nuchia          South Coast Computing Services      [phone]
"You have no scars on your face, and you cannot handle pressure." - Billy Joel

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

Date: 17 Mar 90 07:40:44 GMT
From: elroy.jpl.nasa.gov!usc!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!srcsip!jhereg!quest!viper![e-mail]  (David Messer)
Subject: Re: Challenger last words

In article <[e-mail]6> [e-mail] writes:
 >In article <[e-mail]> [e-mail] (David Messer)
 > writes:
 >>Yes, the last words recorded were:  "No, I wanted a BUD Light!"  :-)
 >
 >You are quite a jerk, aren't you ?

Hmmm...  Suppose I agreed with you, what would that make you? ;-)

Seriously, I find that humor makes lifes tragedies easier to
take.  I also find those who can't see the humor in such
situations horribly depressing.  But, to each his own...
--
Remember Tiananmen Square.           | David Messer       [e-mail] -or-
                                     | Lynx Data Systems  ...!bungia!viper!dave

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

Date: 17 Mar 90 03:57:15 GMT
From: nuchat![e-mail]  (Norman C. Kluksdahl)
Subject: Re: Coilgun on a 747 - supplies to orbit at $20/lb?

In article <[e-mail]> [e-mail] (Vincent Cate) writes:
>>Ever hear of recoil?
>
>                        If the gun weighs 50,000 lbs the gun will go
>backwards at 1/1000th the velocity of the 50 lb projectile.
>                                          At 1/3 g something moving at
>15 MPH can stop in a couple seconds and about 20 feet.

Sure.  You want to fly a 747 that has 25 tons shift by 20 feet?
Does the phrase "death wish" mean anything to you?

No doubt such an arrangement would shatter every conceivable limit
on the CG limits of the aircraft.  Plus, you have to consider that
the force necessary to stop about 25 metric tons has to come from
the aircraft.

You find someone willing to try, and I'll shake your hand when you're
done and buy you a beer.  Just so long as I don't have to be in the plane.

=====================================================================
Norman Kluksdahl
  ...!nuchat!moe

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

Date: 17 Mar 90 10:07:12 GMT
From: agate!brahms.berkeley.edu![e-mail]  (Dmitry Gokhman)
Subject: Re: What was Challenger really up to?

In article <[e-mail]> [e-mail] (Mike Van Pelt) writes:
> A laser wouldn't be illegal even if it were there.  It would be
> unlikely in the extreme to be powered up and able to discharge during
> the ascent.  (What would its power source be?  Solar cells?  Folded
> and stowed in the dark cargo bay.  Nuclear reactor?  Couldn't be
> running during the ascent, or it would irradiate the crew.)

Have you heard of chemical lasers perchance?  They are definitely a
part of SDI.  As far legality is concerned, I wouldn't let the latest
political scandals lead one to believe that only illegal goings on
merit concealment/cover-up.  Mind you I still believe in the O-ring theory.
Are the votes in on the G-spot theory? :-)
---------------------------------------------------------------
- Mr. Gumby    * \oo7    Dmitry Gokhman
   says:        `/v/-*   Brahms Gang/University of Cauliflower/
MY BRAIN HURTS  J  L     Broccoli CA 94720
---------------------------------------------------------------

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

Date: 17 Mar 90 05:51:52 GMT
From: elroy.jpl.nasa.gov!zardoz.cpd.com!dhw68k!ofa123![e-mail]  (Wales Larrison)
Subject: Re: Reliability, Bureaucracy, and Spaceflight Costs (long)

Henry, just to offer a quick response to your message on reliability,
bureaucracy, and spaceflight costs....

>Summary:  the costs of spaceflight are driven largely by desired
>mission reliability.  Bureaucracies tend to desire reliability as
>high as possible, without regard to cost.  Corporations may
>_or_may_not_ do "better," depending on their internal structures.

>If you're willing to accept, say, 85% mission reliability, you can
>build things a lot cheaper.  Use good design tools, but don't over-
>analyze everything.  Don't test every incoming part to death.  Assume
>that your workers know what they're doing, and don't pay QC people to
>hawk their every move.  In short, wait for something to break before
>you try to fix it.
  Hmm... I thought I agreed with this, but after some reflection, I
really don't.  Here's why...
  Current space launch system reliability is driven by a vicous circle
of circumstances - highly expensive systems must be made highly
reliable to avoid the consequences of their failure, which further
increases the costs, and forces them to be more reliable, which ....
  There are other ways.  A couple of years ago I managed systems
engineering for a joint USAF/NASA launch vehicle contract which
focused on designing a $300/lb launch vehicle.  There were several
different ways identified to meet the goal - one of our competitors
focused on a very reliable (and very expensive) reusable system to
reduce recurring costs.  We found we could probably reduce the costs
below the target $300/lb by focusing on simplicity (it can't fail if
you don't have one) and on process control. I can't emphasize enough
the importance of process control and reliability - you can spend
forever trying to inspect a lemon into a winner, and never succeed.  A
system designed to make lemons will make lemons, whereas a well-
designed system will reliably produce quality. And if a failure
occurs, you'd better know what caused it really quickly.
   However, this will cost up-front money.  Regardless of whether you
call it TQM, simultaneous engineering, QFD, systems engineering,
Deeming, or Taguchi methods, you spend bucks early in the design
program to test, verify, and validate your process.  We didn't try to
inspect for .99999 reliability, but aimed at designing a system for an
achievable .98 (and I think we could  have beat that!)
   Politically, this approach is suicide.  You can't get increased up-
front development money (What's the matter?  You don't know how to
build this thing?) Much of the problems on the shuttle program, in my
opinion, are based upon the lack of early development money to explore
and exploit alternative development paths in the early 1970's.  The
full-up testing and development approach (as was done on Saturn)
turned out to be a mistake, as it limited the ability to examine,
test, and refine the system parameters before the final design had to
be frozen.  Congress and OMB are the real culprits behind this - there
were not dollars to do this, and the continual dollar flucuations and
rephasings of the program did their share of adding an unncessary
level of turmoil.   U.S. Corporations have the same problem - and they
almost always have a harder time getting money than the government.
   In the end, we lost the USAF/NASA Phase II contract.  We were too
simple - not enough dollars spent on neat technology development like
new rocket engines, and too much money spent on uninteresting things
like welding technology and improved instrumentation.
----------------------------------------------------------------------
Wales Larrison             Space Technology Investor
   "Ad Astra Ab Perspera"  ("To the Stars Through Our Sweat")



--
Wales Larrison
...!{dhw68k,zardoz,lawnet,conexch}!ofa123!Wales.Larrison                             [e-mail]
714 544-0934 2400/1200/300     [PCP: CASAN]

[disclaimer.std]

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

Date: 17 Mar 90 12:35:11 GMT
From: phoenix![e-mail]  (Marc Wayne Mcconley)
Subject: Gerard K. O'Neill lecture

Opening "The High Frontier"

The Princeton Planetary Society will present a talk by Dr. Gerard K.
O'Neill, founder and president of the Space Studies Institute, on
Tuesday, March 27, at 7:30 pm.  Dr. O'Neill is the author of four books,
including "The High Frontier," in which he discusses humanity's
expansion into space.  He is also Professor Emeritus of Physics at
Princeton University.

The evening's presentation will feature a slide presentation, a short
lecture, and an audience question and answer session.

The event will take place in McCormick 101, the auditorium for the
McCormick Art and Archaeology Building, adjacent to the Art Museum at
Princeton University.  For directions to McCormick auditorium or the
Princeton University campus ONLY, call [phone].

For additional information about this event, please call Audrey Robinson
at [phone].

--
Marc W. McConley
Vice President, Princeton Planetary Society
Reply-To:  [e-mail]  ||  [phone]

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

Date: Sat, 17 Mar 90 21:07:50 EST
From: John Roberts <[e-mail]>
Disclaimer: Opinions expressed are those of the sender
    and do not reflect NIST policy or agreement.
Subject: Re: USF


Daniel Pezely remarks that there have been few comments on the proposed
United Space Federation (USF). Here is a reply:

Yes, the USF does sound like a very interesting idea, and something which
could contribute a lot to space exploration, PROVIDED it does not get too
heavily immersed in politics. Many of the topics listed sound like legitimate
areas for fruitful research.

Also from the text, it appears that there is a distinct possibility that
the USF could eventually come to view itself as having a responsibility
to push policies and legislation, perhaps going so far as to negotiate
new Moon Treaties. This might not come about under the current leadership,
but if the by-laws are sufficiently loose, politically-oriented people will
tend to drift to the top. If this should happen, the organization could
become ineffective, or even have a net harmful effect.

It's difficult to tell from the information available which way the USF will
go. There is therefore a tendency to reserve judgement.

The problem with politics is that it's much easier than doing anything "real",
so organizations usually start with politics. Many never get much further.
(Before anyone objects, I also consider terrorism and harassment to be
political.) I would urge people running organizations of this type to push
politics only to the extent that it is necessary to remove legal and policy
barriers that would prevent real accomplishments.

(My own opinions, as usual.)
                  John Roberts
                  [e-mail]

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

End of SPACE Digest V11 #161
*******************