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Subject: SPACE Digest V13 #333

SPACE Digest                                     Volume 13 : Issue 333

Today's Topics:
             Advancing Launch Technology
            Re: Linear launchers on Earth
           Re: economic vs technical limits
             Re: EM Launchers and G loads
         Re: Commercial Space news (5 of 12)
            Yup, it was an aurora.
        Update: Free Cray Time for SISAL Users
                Re: "Follies"

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

Date: 29 Mar 91 01:03:43 GMT
From: zephyr.ens.tek.com!tektronix!sequent!crg5![e-mail]  (Nick Szabo)
Subject: Advancing Launch Technology

In article <[e-mail]> [e-mail] (Tom McWilliams) writes:

>So, Nick, since chemical rockets are too costly and stretched to their limits,
>in terms of cost/kg and technical capability, what do you propose as a fuel
>for getting anything, people or frieght, to LEO?

Good question.  I'll work with GEO and L-5 (roughly equivalent in cost)
instead of LEO, since we are talking about space industry and
colonization, and different technologies differ in their ability to
get to various orbits.  Note again that I am talking about reductions more
than a factor of 5 below today's costs (from $20,000/lb. to $4,000/lb. from
earth surface to GEO or L-5) that should be the focus of government
research.  Near-term incremental advances and changes in scale for
chemical launchers can best be accomplished by private enterprise.  I'll
review some of the possibilities here:

Freight:

Gas gun  ("hyperaccellerator": horizontal or ocean-based vertical)
Electromagnetic Launch (EML): railgun, coilgun, or mass driver
space-manufactured tether & counterweight, combined with:
    gas gun
    EML
    laser launch
    balloon

Passengers:

laser launch
space-manufactured tether & counterweight, combined with:
    laser launch
    airplane
    balloon

There are also many other technologies and combinations of technologies
that could end up providing the lowest cost.  I don't know if it's
published, but Dani Eder and Space Research Associates in Seattle have
written a paper, "50 Ways to Leave Your Planet", that outlines much
of what has been studied.  As in any R&D, some of these technologies
_won't_ pan out, but they all look promising, and need much greater
attention devoted to them.

What many of these technologies have in common is that the energy
source is not stored on board.  This gets us away from the hideous
fuel/structure and fuel/payload ratios of chemical rockets.  Another
strategy is using mass and energy from space, which is potentially much
cheaper than using mass and energy from earth.  Once space manufacturing
technology is mature, earth mass and energy need only get us above most
of the atmosphere, a suborbital regime that takes less than one-third
the energy of going to orbit.  This regime might even be accomplished by
high-altitude airplanes and balloons.

Not only do these technologies represent the best long-term solution,
but many of them (esp. gas gun and EML) could reduce costs for freight
dramatically over the next 10 years, for bootstrapping space industry.
All three types of EML listed (coil gun, railgun, and mass driver) and
at least one kind of gas gun have working prototypes.  Sandia says it can
develop a $500/lb. to GEO coil gun for $2 billion (less than the cost of one
Space Shuttle).  This compares to $20,000/lb. to GEO for chemical rockets:
a reduction by a factor of 40 in five years.  How about let's give Sandia
a chance to show its stuff?

Over the long term, EML or gas gun could drop costs to $10/lb. to GEO
or L-5.  With warm superconductors, the cost could drop much further, my
guess being $1/lb.  Lower space freight costs will, via space industries,
feed back into reduced passenger costs over the long run, in the form
of tethers and other upper stages manufactured in space.

None of these technologies have received significant funding, because
chemical rocket research has unfairly (and to our great detriment)
dominated space launch R&D.  NASA in particular needs a more balanced
program that concentrates on those technologies that have the greatest
possibilities of advance.


--
Nick Szabo            [e-mail]
"If you want oil, drill lots of wells" -- J. Paul Getty
The above opinions are my own and not related to those of any
organization I may be affiliated with.

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

Date: 28 Mar 91 20:45:22 GMT
From: agate!bionet!uwm.edu!rpi!news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Linear launchers on Earth

In article <[e-mail]> [e-mail] (John Roberts) writes:
>Now, when you fire your launcher, the projectile shoots out of the muzzle,
>and -BLAMMO!- ricochets off the slope of the steel mountain, flying off
>into space at a nice, steep, atmosphere-avoiding trajectory.

Uh, nope.  What happens is that you get a small fireball on the side of your
steel mountain, the end result being a small crater in it.  Things don't
ricochet at that kind of velocity.  Think meteorite, not baseball.

>... I believe the shock wave of the projectile passing through the
>atmosphere would generally be great enough to kill everything for several
>miles around (and it could be heard for hundreds of miles)...

Depends on the size of the payload; the lethal-radius numbers I've heard
have been rather smaller.  But yes, 8km/s near sea level is noisy. :-)
--
"The stories one hears about putting up | Henry Spencer @ U of Toronto Zoology
SunOS 4.1.1 are all true."  -D. Harrison|  [e-mail]  utzoo!henry

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

Date: 28 Mar 91 17:36:16 GMT
From: zephyr.ens.tek.com!tektronix!sequent!crg5![e-mail]  (Nick Szabo)
Subject: Re: economic vs technical limits

In article <[e-mail]> [e-mail] (Paul Blase) writes:

[Technical advances on many fronts]

This is a perfect example of why technical and economic arguments
are inseparable when talking about costs.  With all this technology
listed, we are still left with no idea about its impact on costs.
5%?  50%?  Maybe it will _raise_ costs because the new materials are
more expensive?  (This was part of the problem with Shuttle costs).

The general economic/technical idea you were getting at is that rocket
costs will tend to drop at about the same rate as other chemical forms of
transportation, such as airplanes, because they involve similar technologies
and are impacted by many of the same advances.  That's pretty much what
I've been arguing.  When I can pay $.10 (ten cents) for round-trip from
PDX to Heathrow, I'll start getting ready for space colonization via
chemical rockets.


--
Nick Szabo            [e-mail]
"If you want oil, drill lots of wells" -- J. Paul Getty
The above opinions are my own and not related to those of any
organization I may be affiliated with.

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

Date: 29 Mar 91 20:05:11 GMT
From: zephyr.ens.tek.com!tektronix!sequent!crg5![e-mail]  (Nick Szabo)
Subject: Re: EM Launchers and G loads

In article <[e-mail]> [e-mail] ("Wm. L. Ranck") writes:
>   Now, my question is this.  Why does everyone assume that you want
>maximum acceleration from the system in the shortest possible distance.
>I can see that it make the system cheaper to build and the energy
>efficiency is probably better; but why not build a long rail system
>that accelerates the payload at 2 or 3G over many miles.

The problem pretty much boils down to economics.  (Repeat after me:
"economics and technology are inseparable" :-).  The cost of the
extra superconducting magnets and the civil engineering over tens of
kilometers would really add up, probably to $tens of billions.  Unless
there is demand for launch of $tens of billions of payload with a
specific mass and into the specific orbits best reached by the gun, it does
not make sense to spend so much money on a single configuration.  Right
now, the annual commercial demand for _all_ orbits and payload sizes is
closer to $1 billion.

Over the long term, if low-cost, mass-produced warm superconductors
become feasible, and demand rises sharply, it might be possible
to build very large, low-G EMLs suitable for launching passengers.
Well before then, we will have perfected the technology with
smaller freight EML's costing $100's of millions instead of $tens
of billions.

That said, I strongly agree that there are many important variables for
guns besides length/muzzle velocity.  Like cost/lb., it is only a rule of
thumb and should not be focused on to the exclusion of other variables.
Other important variables for guns are payload and gun stresses (not
just G's in one direction), cost of materials (current superconducting
and high-power equipment is expensive), mass (if we want to mount the gun
on an airplane or under balloons),  and I am sure I have missed quite a few
other important ones.



--
Nick Szabo            [e-mail]
"If you want oil, drill lots of wells" -- J. Paul Getty
The above opinions are my own and not related to those of any
organization I may be affiliated with.

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

Date: 29 Mar 91 18:14:10 GMT
From: idacrd![e-mail]  (Robert McGwier)
Subject: Re: Commercial Space news (5 of 12)

From article <[e-mail]>, by [e-mail] (Wales Larrison):
> (cont)
> tiveness of European and Japanese firms.  However, the NASA
> participation with the AMSC has recently drawn fire from Inmarsat
> (which offers a different type of mobile communications service),
> and from some European governments as being government support for a
> commercial industry.]
>


And if you will pardon me, WHAT THE HELL does Europe think ESA/Arianespace
Matra, Daimler-Benz (which now owns MBB), and all the other semi-private
`corporations' in Europe are but government subsidized and/or out right
ownership
of companies in competition of ours.  The government and treaty granted
monopolies to INMARSAT, COMSAT, others in many areas makes me want to puke
and I can only say IT IS ABOUT TIME THE GD US Government did SOMETHING
to aid OUR companies who are trying to compete with other companies in an
international market where these companies are either owned by the government
or controlled or heavily subsidized by them.

The US is becoming a third world country, exporting more scrap and raw
materials and less high tech (high value, high value added manufactured
goods) each and every day.  I can't understand how or why the US government
will not make SOME move to encourage there industries.

Bob

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

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

Date: 26 Mar 91 16:41:54 GMT
From: amdcad!dgcad!dg-rtp!groupw![e-mail]  (Brian Rice)
Subject: Yup, it was an aurora.

From the Raleigh, N.C., News and Observer, March 26, 1991, p. 4B:
"North Carolina residents got a rare chance to see the
Northern lights and many of them called police to ask if
they knew the source of the red glow in the sky [and
whether it could be arrested and brought to justice :-) ].

"The lights appeared between about 8:30 p.m. and 11 p.m.
Sunday and were seen across most of the state."

So that's it.  Ya know, I probably should have made the
connection with the fact that the aurora looked like a
monster version of the result of a CRAF release, which
was described as an "artificial aurora."  But I had these
preconceived notions that auroras had a curtain-like
appearance and that they "shimmered," while what was seen
here (at least at the times I observed it) was simply
a large spherical glow, fairly static in appearance
except for changes in size and brightness.  Obviously,
those notions of mine are not always true.

Another lesson of this is "Don't believe everything
the fuzz tells you about atmospheric science" (well, I
guess this should be sort of obvious, as nobody asks
Willard Scott about law enforcement matters :-).
I'd love to know how that spurious NWS report came
into existence.

Thanks to Rory McLeod (who observed the aurora from
Charlottesville, Virginia), Phil Fraering, David
Palmer, and Paul Dietz for sending mail.
--
Brian Rice   [e-mail]   [phone]
DG/UX Product Assurance Engineering
Data General Corp., Research Triangle Park, N.C.
"Boy, I hope those dogs eat that cat." --Tula, age 3

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

Date: 28 Mar 91 19:37:08 GMT
From: amdcad![e-mail]
Subject: Update: Free Cray Time for SISAL Users



From: [e-mail]

This is an update of an earlier posting which contained errors.
We apologize to the net commmunity for wasting bandwidth; we think we've got
it right this time...
----------------------------------------------------------------------------

                  The Sisal Scientific Computing Initiative

                       Contacts: John Feo and Dave Cann

The Computing Research Group at Lawrence Livermore National Laboratory (LLNL)
announces the Sisal Scientific Computing Initiative (SSCI).  The Initiative
will award free Cray X-MP time and support to researchers willing to develop
their applications in SISAL, a functional language for parallel numerical
computation.  Members of the Computing Research Group will provide free
educational material, training, consulting, and user services.

SSCI is an outgrowth of the Sisal Language Project, a collaborative
effort by Lawrence Livermore National Laboratory and Colorado State
University and funded in part by the Office of Energy Research (Department
of Energy), U.S. Army Research Office, and LLNL. SISAL provides a clean
and natural medium for expressing machine independent, determinate, parallel
programs. The cost of writing, debugging, and maintaining parallel
applications in SISAL is equivalent to the cost of writing, debugging, and
maintaining sequential applications in Fortran.  Moreover, the same SISAL
program will run, without change, on any parallel machine supporting SISAL
software.  Recent SISAL compiler developments for the Alliant FX/80, Cray X-MP,
and other shared memory machines have resulted in SISAL applications that run
faster than Fortran equivalents compiled using automatic concurrentizing and
vectorizing tools.

Interested participants should submit a 1-2 page proposal by
June 1, 1991 to

      Computing Research Group, L-306
      Lawrence Livermore National Laboratory
      P.O. Box 808
      Livermore, CA  94450

Proposals should describe the research and explain how the work will benefit
from parallel execution on a Cray X-MP.  We will announce accepted proposals
by July 1, 1991.  For more information about the Sisal Scientific Computing
Initiative please contact John Feo ([e-mail]) at [phone]
or Dave Cann ([e-mail]) at [phone].  We look forward to
hearing from you.

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

Date: 26 Mar 91 19:58:18 GMT
From: agate!stanford.edu!snorkelwacker.mit.edu!think.com!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!pitt!nss![e-mail]  (Paul Blase)
Subject: Re: "Follies"

to: [e-mail] (John Roberts)

(re ongoing conversation with Nick Szabo on the economic viability
 of rocket launchers).

 JR> There *is*
 JR> increased interest now in reducing per-pound chemical rocket
 JR> launch costs - for instance the expanded Delta and Titan
 JR> designs described by Allen Sherzer (with hope for up to 2-3X
 JR> drop in cost/pound, and availability in perhaps only a few
 JR> years), and ALS or the new technology launcher system (with
 JR> development expect a decade, and perhaps as much as 10X
 JR> reduction in launch going to extrapolate costs from the past,
 JR> and yet allow that will permit the current curve for exotic
 JR> launchers (flat a change, you must also allow that future
 JR> trends may allow th chemical rocket launchers to change too.

Nice reply to Nick, thank you.

I don't think that we have really started to push the technology of
conventional launchers yet, and new technology is always coming along.
There are three things, that I can think of off hand, that contribute to
a launcher's cost: fuel, craft weight, and manufacturing cost.

- I read in AW&ST where the Japanese are working on an air-breathing rocket
design, where air is scooped in and liquified in flight.  Oxidizer only
must be carried for the exoatmosphere portion of the flight.  Not having
to carry LOX would not only reduce the fuel costs, it would make the
whole craft lighter and cheaper to build.

- With the NASP project, there is a great deal of research going on in the
use of composite materials for things like cryogenic fuel tanks.  Using
these materials will make launcher bodies lighter and stronger.  New
materials, in particular ceramics, may also make the engines cheaper.

- One reason that individual rockets cost so much is that the market is
limited.  In general, if the launch rate would go up, the per-unit cost
would go down.  Especially if we could agree on a limited family of launchers
that could be combined to launch any desired payload - rather like the
Soviets recycle all of their designs, strapping things together to reach
the desired capability.

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

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

End of SPACE Digest V13 #333
*******************