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Subject: SPACE Digest V13 #354

SPACE Digest                                     Volume 13 : Issue 354

Today's Topics:
              Re: More cost/lb. follies
         Re: NY Times Article: Nuclear rocket
      SOLAR TERRESTRIAL BULLETIN - FLARE IMPACT EXPECTED
               nuclear rockets
          solid motor failure at edwards...
             Re: Fred on the Moon
           Air Force small launch contract
          Re: Government vs. Commercial R&D
              Re: More cost/lb. follies

Administrivia:

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

Date: 4 Apr 91 01:32:27 GMT
From: swrinde!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!aplcen!jhunix![e-mail]  (Thomas G Edwards)
Subject: Re: More cost/lb. follies

In article <[e-mail]> [e-mail] (Paul Blase) writes:
>to: [e-mail] (Bob Pendleton)
> BP> Reusable, rugged, and low tech rockets should give a low cost
> BP> per pound to orbit.  From what I've read I'm convinced that
> BP> this approach can work.

>Check out my previous posting on the ALS.  What, I think, Nick and others
>are doing is confusing state-of-the-art performance with optimal price/lb
>performance.  The best rocket will not give the most economic performance
>simply because getting the last 10% of performance out of a high-tech
>engine will cost far more than the first 90%; putting 2 low-tech engines
>on a booster is cheaper than putting a single high-tech engine with
>equivelent thrust (allowing for weight differences).

Whats more, we need to separate manned vs. unmanned launch
technologies.  We can dramatically lower cost to orbit by accepting
5%-10% launch failures (for relatively cheap satellites...the insurance
question raises it's ugly head here though).  No one would be
thrilled with killing 5%-10% of all astronauts, so we spend the
extra money and add redundancy to manned missions, but use cheap,
low-tech, not even all that dependable boosters.

Anyone remember SeaDragon?  A large low-tech booster which would
launch from sea after being inverted by a water-ballast
section.  It used decidedly non-delicate, low-tech parts so that
re-usable stages could be recovered from high altitudes requiring a
minimal amount of on-board recovery apperatus.

-Tom

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

Date: 3 Apr 91 17:51:00 GMT
From: agate!bionet!uwm.edu!spool.mu.edu!munnari.oz.au!metro!cluster![e-mail]  (Raymond Lister)
Subject: Re: NY Times Article: Nuclear rocket


 >  Article xxx of sci.space:
 >  From: [e-mail] (Phil Fraering)
 >  Subject: NY Times Article: Go out and get now!
 >  Date: 3 Apr 91 16:43:42 GMT
 >
 >  Run, don't walk, out to a newsstand and get a NY Times. It has an article
 >  on a nuclear rocket supposedly being secretly developed by the DoD ...


>Article xxx of clari.tw.space: [cross refed to several clari news groups]
>From: [e-mail] (ELIOT BRENNER)
>Subject: Nuclear rocket being developed
>Date: 3 Apr 91 15:31:24 GMT

    WASHINGTON (UPI) -- The Pentagon is trying to build a nuclear-powered
rocket to boost huge payloads, satellites or weapons into space,
scientists and government sources said Wednesday.
    Rather than using conventional chemical rocket fuels to generate a
blast of hot gases to propel a rocket into space, the project involves
vaporizing liquid hyrdogen into a far stronger exhaust stream by passing
it over a bed of nuclear fuel pellets generating heat as high as 3,000
degrees.
    Internal government documents, obtained on the condition that their
source not be divulged, show the program is still young and years away
from completion. The documents also say the government already has
studied safety hazards that might be associated with a sub-orbital test
flight that could pass over the Antarctic and New Zealand.
    The existence of the program was revealed by the Federation of
American Scientists, which objects to using nuclear reactors in flight
operations close to Earth, preferring that the use of nuclear power be
held solely to deep space missions.
    Work on the project is being monitored by the National Aeronautics
and Space Administration, long interested in using reactor propulsion to
drive interplanetary spacecraft. Nuclear power packs already are in use
to produce electricity for spacecraft on long missions.
    Steven Aftergood, a senior FAS research analyst, said a nuclear-
powered rocket could release radiation into the atmosphere, with some of
the fissionable material being transferred into the exhaust gases as the
liquid hydrogen is vaporized. He said test of a nuclear rocket engine
during the 1960s, in a program known as Rover, produced radioactive
releases.
    The current program is code-named Timberwind and is being conducted
by the Strategic Defense Initiative operation within the Pentagon, the
unit charged with developing defenses against ballistic missiles. It
envisions space-based weapons along with sensing satellites to work in
conjunction with ground-based missiles.
    The SDI office had no immediate comment on the matter.
    Aftergood said that studies have shown that a Titan 4 rocket equipped
with a nuclear engine could put a payload of up to 70 tons into a low
orbit while a conventionally powered Titan 4 could loft 20 tons.
    A reactor-powered rocket is believed capable of generating double the
specific impulse, a measure of rocket power, of the main engines on the
space shuttle. Specific impulse defines how long a pound of a fuel will
produce a pound of thrust. The shuttle's engines, the most efficient in
the world, produce a specific impulse of 455 seconds. A reactor rocket
is believed capable of a specific impulse of more than 900 seconds.
    Aftergood said that a nuclear-powered rocket could lift off under its
own power or use a conventional booster to get it up and away from Earth
before kicking in the nuclear thrusting device.
    The proposed flight test envisions using a conventional booster to
get up into the atmosphere before the nuclear aspect was activated.
    The Washington Post reported Wednesday that U.S. officials have told
congressional leaders that reactors on either military or civilian
rockets would not be started until they reached an altitude high enough
to prevent any radioactivity generated during their use from re-entering
the atmosphere.

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

Date: Wed, 3 Apr 91 12:29:44 MST
From: [e-mail] (CARY OLER)
Subject: SOLAR TERRESTRIAL BULLETIN - FLARE IMPACT EXPECTED
X-St-Vmsmail-To: st%"[e-mail]"

                /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\

                        SOLAR TERRESTRIAL BULLETIN

                              03 April, 1991

                    Flare Impact Assessement Update

                /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\


UPDATED FLARE IMPACT ASSESSMENT

     The major class M6/2B flare of 02 April did manage to eject protons.
Protons passed event thresholds of 10 pfu at greater than 10 MeV at 08:15 UT
on 03 April.  Protons reached a tentative peak of 25 pfu at 09:10 UT and have
since declined to around 18 pfu as of 18:30 UT.

     We are currently expecting a terrestrial impact from this latest flare.
With the proton event now in progress, models are indicating a moderate to
high probability for a terrestrial impact.  The geomagnetic field is expected
to become more active on 04 April.  Activity will most likely reach at least
minor storm levels.  Models are suggesting an estimated A-index value of
about 35 to 40 for 04 April, falling to about 25 on 05 April.  There is a
chance activity could be higher than predicted.  There is also a chance that
no impact will occur at all.  However, considering all aspects of this flare,
a terrestrial impact is now expected.  The geomagnetic storming (if it
occurs) should begin somewhere near 18:00 UT on 04 April (give or take
several hours).  There was no Type II sweep observed with this event (which
does not necessarily mean there wasn't a Type II which occurred), so we are
leaning slightly towards a gradual storm commencement rather than an SSC type
magnetic signature.  But either is possible.

     Auroral activity over high latitudes will reach high levels if this
disturbance materializes.  Some periods of major magnetic storming are
possible over middle and high latitudes (particularly high latitudes).
Middle latitudes will likely witness mostly moderate auroral activity with a
risk for brief periods of high auroral activity.  Since lunar phase will not
interfere with attempts to view auroral activity, some southerly middle
latitude areas may be able to witness low levels of auroral activity far
to the north or northeast.  It will be difficult, however, to spot auroral
activity with the naked-eye that far south.

     HF propagation conditions should become somewhat degraded on 04 April if
a terrestrial impact materializes as expected.  Conditions are already
degraded more than usual due to the enhanced geomagnetic and auroral activity
which has been observed lately.  A further decrease in the quality of
propagation is expected on 04 April over most latitudes.  However, no
blackout conditions are expected for the middle and low latitudes.  This
storm event (if it occurs) will not be nearly as powerful as the last major
geomagnetic storm event which occurred in March.

     VHF propagation conditions will remain mostly normal to below normal on
04 April.  Middle and high latitudes may experience periods of auroral
backscatter communications, particularly in the late afternoon and near local
midnight.  The extent of the auroral communications will depend on the
magnitude of the geomagnetic activity.  If activity reaches levels currently
expected (A-index of 35), no significant widespread auroral backscatter will
likely be observed.  However, local sporadic auroral backscatter will be
possible over the middle latitudes if magnetic activity reaches these levels.
More common auroral propagation will occur over the northerly middle and high
latitudes.

     A POTENTIAL GEOMAGNETIC STORM WARNING has been issued for 04 April.
This recent flare combined with the coronal-induced magnetic activity should
push the geomagnetic field into low to moderate intensity minor storming.
Conditions should improve somewhat on 05 April, although a return to more
quiet levels is not expected for several days.

PLEASE SEND ANY REPORTS OF AURORAL ACTIVITY, AURORAL BACKSCATTER
COMMUNICATIONS, HF DEGRADATION OR OTHER ANOMALIES TO:  [e-mail].
PLEASE INCLUDE THE TIME (UT AND LOCAL), LOCATION OF OBSERVATION AND A SHORT
DESCRIPTION OF THE PHENOMENA OBSERVED.  THANKS TO ALL THOSE WHO TAKE THE TIME
TO SEND IN REPORTS.

The following alerts are IN PROGRESS:

  - SATELLITE PROTON EVENT ALERT (CURRENT LEVEL: 16 PFU @ > 10 MEV @ 1830 UT)
  - PROTON FLARE ALERT (02 APRIL)

The following warnings are IN PROGRESS:

  - POTENTIAL GEOMAGNETIC STORM WARNING (FOR 04 APRIL)
  - POTENTIAL POLAR CAP ABSORPTION EVENT WARNING (40% PROBABILITY)
  - POTENTIAL POLAR TO HIGH LATITUDE HF SIGNAL BLACKOUT WARNING (30% PROB)
  - POTENTIAL MAJOR SOLAR FLARE WARNING


**  End of Bulletin  **

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

Date: 3 Apr 91 21:45:17 GMT
From: emperor![e-mail]  (Dave Rickel)
Subject: nuclear rockets

I saw an article in the local paper today about a nuclear booster the DoD was
supposed to be developing for SDI.  From what i could gather, the working
fluid was hydrogen, the Isp was on the order of 900 secs, and they were
talking about testing in the atmosphere.  That would tend to imply a large
thrust.  Ahh.  The paper said the project was code-named Timberwind, was
secret, and that the source was talking on conditions of anonymity.

I assume there isn't any other information available, like how far along
they are, what the weight and thrust and rough size of the thing are, what
type of reactor is being used, etc.  I'm kind of curious about how this
compares to some older nuclear rocket programs--has any progress at all
been made in the last 25 years?

Someone last year was going to submit a summary of the Dumbo nuclear rocket
proposal (a contemporary of NERVA, that lost out because it was too ambitious).
Our news feed was flakey at the time; if the summary did get posted, could
someone email me a copy?  Thanks.


david rickel
uunet!emperor!daver

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

Date: 2 Apr 91 23:26:07 GMT
From: sco!gorn![e-mail]  (arvey j. shier)
Subject: solid motor failure at edwards...

does anyone out there know what happened at edwards afb with regard
to a solid motor test for titan 4...it was my understanding that
the titan 4 was already an operational booster vehicle which
utilized 7 segment solid rocket motors as compared to the
5 segment motors in the titan 3 booster....it is possible that
an advanced version of the 7 segment motor is in development...i
am a retired aerospace engineer who worked with the solid rocket
motor development early on...i have lost touch and would like to
know what happened at edwards the other day...i can recall with
sharp memory a failure experienced at edwards in the mid-sixties
during the development of the titan 3 booster vehicle...

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

Date: 3 Apr 91 18:30:03 GMT
From: prism![e-mail]  (Daniel McGurl)
Subject: Re: Fred on the Moon

In article <[e-mail]> [e-mail] (Tom McWilliams) writes:
>Re; Fred on the Moon.

[lot's of reasons to place Fred on the moon]

I can only see two major problems with this:

1) Where do you do the 0g crystal growing?

2) Do you gain anyhitng because you have to have extra fuel and packaging
to land on the moon, and then get materials back.

--
Danny McGurl                               "How straightforward the game
Office of Information Technology and       when all its rules are respected."
Information and Computer Science Major at:
Georgia Institute of Technology                     ARPA: [e-mail]

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

Date: 3 Apr 91 22:31:00 GMT
From: o.gp.cs.cmu.edu![e-mail]  (Vincent Cate)
Subject: Air Force small launch contract


I have been told (by somebody who stands a good chance of knowing)
that Orbital Sciences Corp is the only company with a bid in on the
Air Force contract for 5 small launches per year.  Does anybody know
if this is true?  Does anybody know of any other company bidding
on this contract?

Assuming this is true, does anyone know why?  It seems there are a
number of companies bidding on the Motorola replacement launches and
I would think these same companies would be interested in the Air Force
contract too.

Thanks for any info,

      -- Vince

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

Date: 3 Apr 91 00:46:04 GMT
From: mips!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!emory!wa4mei!ke4zv![e-mail]  (Gary Coffman)
Subject: Re: Government vs. Commercial R&D

In article <[e-mail]> [e-mail] (Nick Szabo) writes:
>
>A review of the statistics: of U.S. patents granted in 1989, 79,088 (76%)
>were issued to corporations, 23,624 (23%) to private individuals, and
>700 (1%) to governments.  Some of the corporate and individual patents
>are aided directly or indirectly by government money, of course.  But
>the bottom line is that direct DoD, NASA, DOE, etc. work accounts for
>only a very small fraction of our technological advances.

All this proves is that government research is rarely patented. Much of
it is released into the public domain (it was after all publicly funded),
and much of it is classified (military applications). So the patent
statistics are not a reasonable measure of the productivity of government
research. This doesn't mean that government research is good or productive.
It merely means that these statistics don't prove that it is not.

Gary

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

Date: 3 Apr 91 18:18:24 GMT
From: swrinde!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: More cost/lb. follies

In article <[e-mail]> [e-mail] (S. J. Okay) writes:
>Namely, how much are parts like this interchangeable? Is your standard
>Delta or Titan a made-to-order unique vehicle, or are there certain things
>that are more or less off-the-shelf parts.

Engines are often *almost* off-the-shelf parts, because they have some
tendency to outlast specific booster configurations.  Delta's main engine
is a slight variant of the Atlas "booster" engine, which in turn is a
derivative of the Navaho booster engine.  (Navaho was the last of the
USAF's enormous intercontinental cruise missiles in the 50s, and was
cancelled before first flight.)  Other variants of the same engine were
the first-stage engines for the Saturn I and Saturn IB.  On the other
hand, there is usually some small degree of customization; Delta engines
are not interchangeable with Atlas engines, although major subassemblies
should still be.

That's sort of the overall pattern, in fact.  Various subsystems often
are slightly-customized variations on standard parts.

>...get an engine assembly from Engines 'R' Us, mate it to an third-party
>fuel tank and then wrap your own external skin around it?

(Minor quibble:  there is no separate external skin.  The tank wall has
fuel on one side and air on the other, although hydrogen tanks in particular
may have a layer of insulation either inside or outside.)

It's not quite that easy.  Things like the tankage and structure tend to
be fully custom-built, there is a lot of minor customization even of the
standard subassemblies, and considerable effort is needed to make everything
work together smoothly.  There isn't enough of a mass market for varying
configurations to justify plug-together launchers.

>I realize avionics are pretty specific and probably wouldn't apply here...

Actually, avionics can be pretty generic, since a computer is a computer
(although it may have slightly different software).  Details like the
electrical interface to the propulsion hardware can vary a lot, though.
--
"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

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

End of SPACE Digest V13 #354
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