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Subject: SPACE Digest V10 #170

SPACE Digest                                     Volume 10 : Issue 170

Today's Topics:
              More Info On NASP
          Re: Will NASA Contaminate Florida?
           Re: Catholic Anti-Technologists
           Re: Try thinking before stinking
        Re: Amateur Earth Approaching Asteroid Project
                 Re: finally!
            Re: propulsion systems
          Measuring velocity on a spacecraft
    Praying for disaster (was: The true value of Galileo)
              Re: The Anti-RTG Movement
               Magellan's gravity boost
----------------------------------------------------------------------

Date: 20 Oct 89 22:57:51 GMT
From: ogccse!littlei!omepd!omews10.intel.com![e-mail]  (Larry Smith)
Subject: More Info On NASP


In:<[e-mail]> (SCHREIBER, O. A.) writes:
>Has anybody ever proven that single stage to orbit is possible?

No, but we're just talking launcher packaging. We just haven't designed
the packages yet. The more interesting issue(s) for me are:
1. Is SSTO important?
2. Which method? (A rocket or an airbreather or a combination).

The answer to number 1 & 2 is too important to the future competitiveness
of American launching technology to ignore.

>Also, a hypersonic vehicle has to navigate in a narrow
>velocity-altitude region, ...
>... too slow and high and it does not climb,
>too fast and low and it melts.
>Any opinion?

Yes, good points. But, back in 1987 work at U of Maryland by
Bowcutt, Corda, and Anderson resulted in a new type of hypersonic
waverider that (theoretically) has broken the 1978 Kuchemann
hypersonic L/D barrier. Kuchemann's old barrier, measured for
REAL vehicles is: L/D Max = 4(M + 3)/M.
Bowcutt, Corda, and Anderson's new THEORETICAL barrier:
L/D Max = 6(M + 2)/M.
Corda and Anderson, one year later, have further generalized their
findings to a more general class of flow fields.
One major significance of these results are that for the first time,
hypersonic viscous effects were included (ie: the work attempted
to be more real world).

One of the biggest problems on NASP now, is the efficiency of the
scramjet at increasing Mach numbers. According to Johns Hopkins-APL
Scramjet design technology to Mach 7-8 is well established.
(JH-APL, is one of the leading ramjet/scramjet research facilities in the
world. Fred Billig, who with Dugger, were the first to apply
for a patent on a scramjet powered missile in 1961, is the head of the
ramjet group there)

A big problem above Mach 7-8 now is what inefficiency percentage
do you assign to your scramjet engine model components, due to the
fact that above Mach 7-8, we have no real data to validate the codes?
By the way, even being off 1% on your component efficiencies, can cause
MAJOR loss of performance at high Mach in a scramjet. As a matter of
fact, some researchers are proposing that scramjets have a new Isp metric,
different from that of a rocket engine. This new Isp metric, takes into
account the effective drag. It is:
    Effective Isp = (Thrust - Drag)/Propellant Flow.
The drag takes into account some new high temperature/real gas effects
that aren't traditional 'drag' components.

Now this is NOT an indictment of scramjets, but it shows
the current REAL NEED to build HARDWARE to work some of these things
out. This is really the goal of X-30/NASP. NOT to build a Orient
Express, or a new SR-71, or even a payload orbiter. But, to
develop the required technologies to potentially build NASP Derived
Vehicles (NASPDV or NDV), and NASP Technology Derived Vehicles (which may
not be airplanes at all. ex: high L/D orbital transfer vehicles that
can do orbital plane changes with air breathing engines via the upper
atmosphere, new high Isp air breathing rockets, new cargo shuttles
without tiled skins).

Larry Smith

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

Date: 20 Oct 89 18:51:16 GMT
From: crabcake![e-mail]  (Kenneth Arromdee)
Subject: Re: Will NASA Contaminate Florida?

In article <[e-mail]> [e-mail] (Clifford Johnson) writes:
>>The radioactivity of other forms of plutonium IS irrelevant to the
>>risks of the Galelio probe. So is the toxicity of dioxin. So is the
>>toxicity of PCB's. It the discussion is the risk of Galelio, not the
>>risks of anything else.
>I admit that the radioactivity of the 239 isotope NOT in Galileo is
>irrelevant to one who is unaware that the radioactvity in nuclear
>bombs is very dangerous, and so are not informed of anything by
>being told that Galileo's 238 isotope is 300 times stronger.

I would like to inform you that nuclear bombs run on fission chain reactions,
and the PU-238 in Galileo does not.  By saying "radioactivity in nuclear
bombs" you imply that it's 300 times stronger than what goes on in a nuclear
explosion, which is not true.

>>This argument is basically, "You can't prove that it is perfect, so
>>the risk is too large."
>>I consider this luddite thinking, and not a risk analysis.
>No.  The argument is basically that the death of thousands is risked,
>which is too much to risk, at least on an ongoing, repetitive basis.
>By the way, I like being called a luddite.

Do you cross the street to save $5 if you know that crossing the street has
a chance of resulting in your death?  After all, your own life is too much to
risk for $5.
--
"The workers ceased to be afraid of the bosses.  It's as if they suddenly
 threw off their chains." -- a Soviet journalist, about the Donruss coal strike

Kenneth Arromdee (UUCP: ....!jhunix!arromdee; BITNET: arromdee@jhuvm;
     INTERNET: [e-mail])

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

Date: 21 Oct 89 01:00:26 GMT
From: zephyr.ens.tek.com!wrgate!mrloog![e-mail]  (Dan Tilque)
Subject: Re: Catholic Anti-Technologists

Russ Brown and marty ryba write about the support the RC Church gives to
science.  This is more of the same.

The Catholic Church supports an astronomical observatory (called the
Vaican Observatory).  It is a respected institution run by priests (mostly
Jesuits, I think) who are also astronomers.  These astronomers regularly
publish in the various astronomical journals.

The Church gave official approval to the Big Bang theory (as opposed to
the Steady State) in the early 50's.  Admittedly, they did it for
theological reasons and their support had zero scientific influence, but
it does show that the Church was not going abandon all rational thinking
like many of the fundamentalists do.


---
Dan Tilque    --    [e-mail]

"Why did the chicken cross the Mobius strip?"

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

Date: 20 Oct 89 07:15:11 GMT
From: uccba!uceng![e-mail]  (daniel mocsny)
Subject: Re: Try thinking before stinking

In article <[e-mail]>, [e-mail] (Gerald Olchowy) writes:
> Why does this man-nature dichotomy persist?  Human artifacts are
> natural artifacts!

Indeed, how strange that we do not duplicate our own nature in our
own artifacts---yet.

> Because we are not omniscient is no reason to deprecate
> human artifacts in comparison with non-human artifacts.
> Neither is better...they are just different.

I did not think I was deprecating human artifacts. Indeed, I am
happier surrounding myself with them to the exclusion of
artifacts of nature most of the time.

If I admire nature's design, it is because I wish to duplicate
her genius. I can admire the profound wisdom inherent in a
blade of grass, but it doesn't exactly duplicate the function
of a Saturn V, does it.

Much of the angst one detects in this newsgroup revolves around the
difficulty that getting into space presents to our present technology.
Since we must manufacture our artifacts out of massive infrastructure,
instead of simply planting them small and letting them grow more of
themselves, we cannot get into space without massively cooperating
with each other.

Perhaps those who yearn skyward would do well to observe and learn
from the grass under their feet. (That's something to ruminate on...)

> To be against taking any risk, which is what the opponents of Galileo
> would have us do, is to be for fear and irrationality, which is
> to be for the worst in human nature.

The only rational criterion for assessing risk must be economic. To
embrace any risk that appeals to SciFi adventure-indoctrination seems
to me as mindless as rejecting any risk that contradicts NewAgeist
anti-technological paranoia. Urges toward heroism and lumps felt in
the throat are emotional criteria, and as such they are as dangerous
and prone to true-believer mob-think runaway as any other form of
irrationality.

Please note that irrespective of my heartfelt admiration for blades of
grass, I think the Christic Institute's position on Galileo is absurd,
and even if it was not, they should have had the sense to speak up
sooner.

Dan Mocsny
[e-mail]

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

Date: 20 Oct 89 18:18:52 GMT
From: rochester![e-mail]  (Paul Dietz)
Subject: Re: Amateur Earth Approaching Asteroid Project

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

>The CDD is 572x485 pixels, 8.8 x 6.6 mm.`
>
>Plug in some numbers... if you have a 50 cm, f/4 scope, the rows see
>3.3 milliradians of image, so the drift time is over four minutes
>(more at high celestial lattitude).

Correction: drift time is 45 seconds.  Off by 2 pi...

    Paul

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

Date: 20 Oct 89 10:08:00 GMT
From: eru!luth!sunic!mcsun!ukc!icdoc!syma![e-mail]  (Andy Clews)
Subject: Re: finally!

From article <[e-mail]>, by [e-mail] (Henry Spencer):
> Atlantis and Galileo are on their way, SRBs separated and everything
> looking fine.

Thanks for the information, Henry, but, uh, haven't you slipped into the
"I must be the first person in the world to announce this" trap? I'm
sure most of us heard about the launch etc.  on TV and radio before
your posting got around.


--
Andy Clews, Computing Service, Univ. of Sussex, Brighton BN1 9QN, ENGLAND
JANET: [e-mail]   BITNET: [e-mail]
Voice: [phone] ext.2129

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

Date: 21 Oct 89 05:53:11 GMT
From: hplabsb![e-mail]  (David Smith)
Subject: Re: propulsion systems

In article <[e-mail]> [e-mail] (Zeke Hoskin) writes:
>   It would be nice if the summary included things like specific
>impulse (exhaust velocity/g), thrust/nonfuel mass, etc.  For a
>very rough instance: H2/O2 chemical : S.I.400+, T/M abt 50 nt/kg
>                   Kero/O2 chemical : S.I.300+, T/M abt 100
>                   Al/NH4ClO4       : S.I.200+, T/M up to 1000
>     Electrostatic Ion Drive-10KV   : S.I.1000  T/M less than 10e-5

At the moment, I can only offer an improvement on the H2/O2 rocket.
The RL-10 (Centaur) engine long had an Isp of 440 sec;  the version
3 has 444;  version 4 has 449.  I remember reading that the Shuttle
main engines achieve 455.
--

            David R. Smith, HP Labs
            [e-mail]
            [phone]

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

Date: 20 Oct 89 13:17:27 GMT
From: eru!luth!sunic!mcsun!ukc!icdoc!syma![e-mail]  (Andy Clews)
Subject: Measuring velocity on a spacecraft

Quick question (though I suspect not with a quick answer).  How is
velocity measured on a spacecraft travelling through the vacuum of
space?

Email might be best; I'll summarise if possible.

Thank you.

--
Andy Clews, Computing Service, Univ. of Sussex, Brighton BN1 9QN, ENGLAND
JANET: [e-mail]   BITNET: [e-mail]
Voice: [phone] ext.2129

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

Date: 20 Oct 89 15:54:49 GMT
From: att!dptg!pegasus![e-mail]  (Paul S. R. Chisholm)
Subject: Praying for disaster (was: The true value of Galileo)

In article <[e-mail]>, [e-mail] (Jim Bowery) writes:
> I hope the suit to block launch of Galileo fails.  We need
> to see another Shuttle blow up a bunch of astronauts,
> the lives work of many competent and idealistic scientists and
> possibly, 50lbs of Plutonium.  Such an event would finally
> wake us from our opiated stupor induced by eating the rotting
> carrion of Apollo that NASA has been spoon-feeding us for
> TWENTY YEARS.

@sarcasm(on); @insert(super-smiley-with-slightly-pained-look)

No, Dr. Bowery, you're not going nearly far enough.  Clearly, the
biggest problem in our exploration of space is human nature.  What we
really need is a really good, dirty nuclear war that will kill every
human being on the planet.  Without this, there'll never be an
intelligent race on Earth that will go into space the right way.  And
this will have the wonderful side-effect of killing all those
incompetents at NASA, whose sole purpose in life is to *prevent* the
U.S. from making any progress in space, because if we really did, then
we wouldn't need NASA anymore!

@sarcasm(off)

> The cost of such a disaster would be small compared to the
> value of breakout out into the space frontier before the
> Club of Rome comes home to roost.

Excuse me?  You're not seriously suggesting that we're all going to die
in an exponentially-growing pile of whatever, and that we need to set
up a space habitat because everyone on Earth's going do die, are you?

> Jim Bowery, {cbosgd,hplabs!hp-sdd,sdcsvax,nosc}!crash!pnet01!jim,
> crash!pnet01![e-mail], [e-mail]

Paul S. R. Chisholm, AT&T Bell Laboratories
att!pegasus!psrc, [e-mail], AT&T Mail !psrchisholm
I'm not speaking for the company, I'm just speaking my mind.

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

Date: 21 Oct 89 05:53:34 GMT
From: bfmny0![e-mail]  (Tom Neff)
Subject: Re: The Anti-RTG Movement

I wish people would pick up a newspaper before posting.  The
anti-Galileo coalition has been quoted by the wire services as saying
they feel they won the PR battle since Americans are now aware of the
risks.  They actually have not dropped the court case.  (In case anyone
thinks the subject is moot, Ulysses has similar RTGs.)

Regardless of the technical merits of the coalition's case, NASA's siege
mentality has once again managed to yield a public relations debacle.
No sane agency with NASA's desperate need for public goodwill would
treat a concerned citizens group with such contempt.  NASA's position
could be summarized as (1) we filed our forms on time and in triplicate,
so **** off; (2) these airheads don't know what they're talking about
anyway.  Even if both things are true, you don't make friends by
trumpeting them.  And after Challenger, the burden of proof is on NASA,
not whistle blowers, whether that seems fair or not.

A savvy Agency would have bent over backwards to placate the coalition
people, with white room tours and VIP launch tickets and a high level
scientist-to-scientist sit down to air out serious objections from the
coalition's physics people.  The current team of righteous crewcuts does
not appear cut out for such work.  Substitute "ignorant swing vote stix
Congressman" for "coalition people" in the above picture and you may
have a clue why Apollo is dead.
--
DEFINITION, n.  statement of precise   <\<   Tom Neff
meaning of word etc. [F f L (DEFINE)]   >\>  [e-mail]

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

Date: 21 Oct 89 01:54:12 GMT
From: mailrus!sharkey!umich!dip.eecs.umich.edu![e-mail]  (Brian Holtz)
Subject: Magellan's gravity boost

If the attraction between Magellan and, say, Venus is the same
when Magellan is coming and going, how does the encounter speed
up the craft?  Does it have something to do with the fact that it's
passing Venus as they both orbit the the sun?

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

End of SPACE Digest V10 #170
*******************