Date: Sat,  5 Dec 92 18:17:15    
From: Space Digest maintainer <digests@isu.isunet.edu>
Reply-To: Space-request@isu.isunet.edu
Subject: Space Digest V15 #512
To: Space Digest Readers
Precedence: bulk


Space Digest                Sat,  5 Dec 92       Volume 15 : Issue 512

Today's Topics:
       Detonavion vs Deflagration (was Re: Shuttle replacement)
                       NASA employment outlook
                       prg.in 1/93 S&T [Part 2]
                  Robert Goddard and Neil Armstrong
                         Rumors about Hubble
                     Shuttle replacement (3 msgs)
                 STS-48 and "SDI": Oberg vs. Hoagland
           Terminal Velocity of DCX? (was Re: Shuttle ...)
                          Trees in space...

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

Date: 5 Dec 92 16:18:27 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Detonavion vs Deflagration (was Re: Shuttle replacement)
Newsgroups: sci.space

In article <Byp7J8.BJB@access.digex.com> prb@access.digex.com (Pat) writes:
>Gary has been going on
>and on about Flaming rockets crashing into disneyworld. a vehicle
>crashing with deflagrating fuels is much less damaging then a SCUD
>missile with a TNT warhead.  

A SCUD warhead leaves a crater a few dozen feet across at the impact
site. Great for attacking a hardened bunker (provided a SCUD could
hit it), but a few tons of volatile fuel spread over a few blocks
would likely do more damage to soft targets and people. That's why
the military uses napalm instead of high explosives on soft targets.
Fire may be old fashioned, but it's still deadly.

Of course ordinary airliners present this fire risk too, but they
have a proven track record of reliability that makes the odds of
such a crash tolerable. No rocket has that kind of track record
yet, and it will take many thousands of takeoffs and landings to
develop one. Until then, I'd prefer DC to spend it's time near
the surface either over desert or water. That's just prudent,
and cheap, there are good launch sites already present in those 
types of terrain, at least one complete with fuel plant.

Gary

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

Date: 5 Dec 92 19:56:19 GMT
From: Claudio Egalon <claudio@nmsb.larc.nasa.gov>
Subject: NASA employment outlook
Newsgroups: sci.space

BTW, The National Research Council (NRC) offers postodoctoral 
fellowships, for people who has a Ph.D. in Sciences and Engineering, 
to do research work at NASA, some other government agencies  and 
in some aeroespace companies. This fellowship is opened to non-
citizens but, in certain research projects that require security 
clearance, non-citizens do not qualify however, some, if not most, of 
the research opportunites offered by the NRC  fellowship do not 
require security clearance. The salary is somewhere in between 
US$35,000.00 and US$40,000.00 per year and, for senior researchers 
who got his Ph.D. more than five years ago,  this amount can be even 
higher. A good place to request an application would be to contact any 
NASA center (here at Langley, for instance, they have an office that 
deals specifically with these NRC fellowships) or even write to NRC.

Claudio Egalon

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

Date: 5 Dec 92 19:12:30 GMT
From: Earl W Phillips <ephillip@magnus.acs.ohio-state.edu>
Subject: prg.in 1/93 S&T [Part 2]
Newsgroups: sci.space,sci.astro

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end

--------------cut here---------------
hope it made it ok!

*****************************************************************
*                                    | ====@====      ///////// *
* ephillip@magnus.ircc.ohio-state.edu|     ``________//         *
*                                    |       `------'           *
*                 -JR-               | Space;........the final  *
*                                    | frontier...............  *
*****************************************************************

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

Date: 5 Dec 92 20:50:01 GMT
From: MURTY Hema Sandhyarani <murty@ecf.toronto.edu>
Subject: Robert Goddard and Neil Armstrong
Newsgroups: sci.space

	Can someone please post the year when Goddard was born
	and died and the year of birth of Neil Armstrong?

	Thanks,
             

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

Date: Fri, 4 Dec 1992 21:12:01 GMT
From: Stan Bischof <stanb@hpnmdla.sr.hp.com>
Subject: Rumors about Hubble
Newsgroups: sci.space

In sci.space, 18084TM@msu.edu (Tom) writes:


>I heard the strangest rumor recently.  The doubt factor is pretty high,
>but I'm curious if anyone has anything to add about the reality or origin
>of the rumor.

>It goes something like this:  HST is actually in perfect working condition,
>but the military shanghied it, with the bad-mirror cover story, for the
>purpose of inspecting a recently discovered radio signal coming from
>space, presumably from IET's.

>You're buyin' it, right? :-)  Does this sound familiar to anyone, or
>is it a total crock?  One way or the other, how do you know?

Just HAS to be true. 

How do I know?- it makes perfect sense. Everyone knows a couple meter
diameter chunk of glass inside an optical telescope in orbit
is MUCH better at receiving weak radio signals than any radio telescope
on the ground.

Stan Bischof
HPSR

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

Date: 5 Dec 92 16:04:33 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <Byp4Fu.3J@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes:
>In article <70761@cup.portal.com> BrianT@cup.portal.com (Brian Stuart Thorn) writes:
>>I was wondering if anyone else was going to mention that gaffe.
>>I mean, TEN PEOPLE???
>>Okay, you've crewed the fire truck... now who's going to fuel the DC? :-)
>
>How many people does it take to connect a couple of hoses and push the
>buttons to start the pumps?

Following commercial airliner practice, 7.

How many people does it take to operate the liquid hydrogen and liquid
oxygen plant? You've got to have one everywhere DC takes off. I doubt
any zoning board is going to let you do it with one or two. They're 
going to insist on a fully manned facility, just as they do for
liquid air and other explosives plants. Leaking liquid oxygen isn't
something to play with.

How many people does it take to jack up the spacecraft, attach wheels,
and transport it to the launching cradle? Following airliner practice,
it's 12, and they already have their wheels attached.

How many does it take to safely attach it to the launch cradle and remove
the wheels? According to construction site practice, at least 15.

How many people does it take to service the flight deck environmental
system? Two could do it, but I'll bet 5 at minimum.

How many people does it take to mate payloads to the standard containers?
These may be paid by the payload owner, but then so is everything else
in a commercial launching operation. This job will require at least a
couple of engineers and five or six techs working for weeks on the typical
satellite.

How many people does it take to mate those containers to the vehicle?
I'd guess at least 5 based on airliner cargo handling standards.

How many people does it take to pump out the waste tank?
Ok, one, but he'll probably have a helper under union rules.

How many people does it take to stock the food service and vacuum out
the cabin? Two?

How many mission planners, trajectory calculators, and weight and balance
people? Unless flight systems are much more sophisticated than they are
now, the system will have to be reprogrammed for each mission profile
in a custom fashion. Say a minimum of 25 people.

How many accountants and lawyers? This is important! Everyone want's
to get paid and all contracts have to be reviewed. Say three to four
thousand people here. :-)

Then what happens when you need actual *maintenance* work done on the
spacecraft? Engine mechanics, plumbers, welders, electronics techs, etc.
This isn't exactly something you can farm out to some shop on the street
that normally installs cellular phones or fixes cars.

You probably need one or two hundred people on the ground to service
a DC, plus the paper pushing types to back them up. That's for one or
two flights a week with no need for repair service. If you handle fewer,
your ground expenses increase because your people are idle too much of
the time. If you handle more frequent flights, you'll need more people
and more facilities. Delta has 5,000 ground support personnel in Atlanta
and there isn't even a maintenance base here yet (They're negotiating
for the old Eastern facility).

200 people is certainly cheap, a payroll of about 10-15 million dollars
a year at airline pay scale. But that doesn't include the cost of the
fuel plant at each airport, or the launch cradle facilities, or payload
clean rooms, or office space. Seems to me you'd want a single, or maybe 
two launch bases rather than dozens. You'd probably like them to be at a 
low latitude too to take advantage of the increased payload you can lift 
launching East from a low latitude site. Chicago wouldn't make much sense 
unless you were going for polar orbit. With a thin payload margin to begin 
with, you'd expect DC to launch from the most favorable site possible rather 
than some rinky dink local airport at a high latitude that happens to have a 
payload it wants delivered to Freedom. Launch windows would be tight as well 
with little fuel margin available to dogleg, or chase your destination in 
orbit.

Gary

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

Date: Sat, 5 Dec 1992 21:14:44 GMT
From: Paul Dietz <dietz@cs.rochester.edu>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <1992Dec5.160433.17868@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes:

> How many people does it take to operate the liquid hydrogen and liquid
> oxygen plant? You've got to have one everywhere DC takes off.

Well, no.  Liquid oxygen and hydrogen can be delivered by truck or
rail car.  Haven't you ever driven behind a liquid hydrogen tanker
truck on the interstate?  And LOX is delivered by tanker to hospitals,
universities and industry all the time.

You may want a holding tank, but that's much less complex than
a separation plant.

	Paul F. Dietz
	dietz@cs.rochester.edu

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

Date: Sat, 5 Dec 1992 22:01:50 GMT
From: "John S. Neff" <neff@iaiowa.physics.uiowa.edu>
Subject: Shuttle replacement
Newsgroups: sci.space

In article <1992Dec5.211444.22824@cs.rochester.edu> dietz@cs.rochester.edu (Paul Dietz) writes:
>From: dietz@cs.rochester.edu (Paul Dietz)
>Subject: Re: Shuttle replacement
>Date: 5 Dec 92 21:14:44 GMT
>In article <1992Dec5.160433.17868@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes:
>
>> How many people does it take to operate the liquid hydrogen and liquid
>> oxygen plant? You've got to have one everywhere DC takes off.
>
>Well, no.  Liquid oxygen and hydrogen can be delivered by truck or
>rail car.  Haven't you ever driven behind a liquid hydrogen tanker
>truck on the interstate?  And LOX is delivered by tanker to hospitals,
>universities and industry all the time.
>
>You may want a holding tank, but that's much less complex than
>a separation plant.
>
>	Paul F. Dietz
>	dietz@cs.rochester.edu

Several times a year there are accidents involving tank trucks carrying 
gasoline or propane, sometime the consequences are very serious. I cannot
recall hearing of any accidents involving shipments of LH2 or LOX. Why is 
that? 

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

Date: 5 Dec 1992 13:14 MST  
From: "James J. Lippard" <lippard@skyblu.ccit.arizona.edu>
Subject: STS-48 and "SDI": Oberg vs. Hoagland
Newsgroups: sci.skeptic,sci.astro,sci.space,alt.alien.visitors

In article <1992Dec4.215702.5218@news.cs.brandeis.edu>, corbisier@binah.cc.brandeis.edu writes...
>James Oberg will _of course_ have an explanation.  He is a member of
>PSICOP and works with Philip Klass, THE well-known skeptic "nothing-
>is-real" other famous member of PSICOP.  I've been seeing more and
>more things from Oberg lately, and I *never* see this connection 
>mentioned, only his NASA ties.  
> 
>Robert Sheaffer may be "Skepticus Maximus", but for the rest of us
>with open minds, please consider the source.
> 
>Barb

Given that you've failed to address Oberg's *arguments* at any point,
and that you've complained about his affiliation with an organization
whose name you don't even know how to spell (there is no such organization
as "PSICOP"), why should *anyone* take your posting as any evidence at
all against the reasonability of the posted Oberg rebuttal to the alleged
STS-48 UFO?

Jim Lippard              Lippard@CCIT.ARIZONA.EDU
Dept. of Philosophy      Lippard@ARIZVMS.BITNET
University of Arizona
Tucson, AZ 85721

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

Date: 5 Dec 92 16:52:19 GMT
From: Gary Coffman <ke4zv!gary>
Subject: Terminal Velocity of DCX? (was Re: Shuttle ...)
Newsgroups: sci.space

In article <BypAIA.CBn@access.digex.com> prb@access.digex.com (Pat) writes:
>In article <1992Dec3.143759.2535@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes:
>>In article <BynsG8.E5p@news.cso.uiuc.edu> jbh55289@uxa.cso.uiuc.edu (Josh 'K' Hopkins) writes:
>>>necessitate them.  Just why can't a launcher be an airliner anyway?
>>
>>The proposed DC *is* a rocket, it *is* a low margin system as any
>>SSTO has to be, and it has exactly *zero* flight history. It will
>
>	You are making a mistake again.  i think you are confusing
>a narrow payload margin with a narrow safety margin.....
>Now DC-Y,X  have small payload practions to Launch weights,  but
>they are being designed with high safety margins.
>Gary are you an engineer?  safety margins are a function of use,
>based upon past experience and law.  

I'm an EE not a PE, but I know enough to figure out that if your
mass margins are extremely thin you don't add extra mass if you
can trim it out. In structures and in engines, beefier parts almost
always mean higher reliability. A truck engine is usually good for
a million miles while a formula one engine may last 100. They both
put out roughly the same amount of power, but one masses a lot more
than the other.

>The DC is being built with the same margin of safety that airlines have.
>Engines will run at 2/3rds max power with detents at 75% .
>Rated power will be significantly below max power.  All structural
>elements will be below rated strength.  now if you fly
>a DC-X through Thunderheads, you might rip her up, but if you stay to
>clear air, i imagine she will have a long service life.
>The problem with the shuttle is her engines are run to with 5% of MAX
>power.  the structure is pushed to within 10% of deformation limits.
>hence extensive inspection and rebuiilds must be conducted on each flight.
>if a micro crack were to occur on an srb strut, they'd fail.
>the DC is designed to withstand degradation in vehicle integrity until
>some major milestone is passed.

So you're saying that if we just throttle back Shuttle to 75% power
and brace a couple of struts, we'd have a system as safe as DC???? 
Or a 747???? I don't think so. I believe that spacecraft have to push 
the envelope a lot harder than an airliner just to achieve orbit. 
Otherwise, lets just fit a big oxygen tank to a 747 and forget all 
this high tech stuff.

Look, I'm not trying to be dense here, but in circuit design we know
that the more parts you have in a circuit, and the harder you push
them, the more likely you'll have a failure. So you try to simplify,
and beef up what remains to stand the maximum expected stress. Redundant
power supplies tend to fail redundantly into a shorted load. Add protective
circuits, and the protective circuits will fail in such a way as to take
the system off line at the most critical moment. Simplicity, two wires
make a light, the lever and the inclined plane, strict quality control, 
extensive testing, never depend on an active system when a passive system
will do, never have two critical systems with a common failure point, always
have a totally separate backup system, these are the routes to reliability 
in my business.

Gary

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

Date: Sat, 5 Dec 1992 18:42:05 GMT
From: Eric J Bales <balesej@ucunix.san.uc.edu>
Subject: Trees in space...
Newsgroups: sci.space

I posted this after having a thought on another group, but no one there
could find any information on it...

How would a tree grow in zero-g's?  I mean, if you take a tree enclose
it in a bubble of some sort, with the roots in one half and the trunk
and branches in another half, what would it look like after a couple
years?  Air wouldn't be moving except what little was necessary to keep
it fresh, and the roots would be provided with nutrients.  (So, please
don't see read Niven's The Integral Trees, as this is a totally different
situation! :-))

2.  Would it grow any different in free-fall as opposed to zero-g's?  It
seems to me it would not, but I don't know for sure...

-- 
balesej@ucunix.san.uc.edu - atreis@tso.uc.edu		 -Eric Bales-
ebales@ddt.eng.uc.edu - at098@Cleveland.Freenet.Edu
		        -The second dolphin-
Dolphins. Soon you will be one of us, and then you will understand.

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

End of Space Digest Volume 15 : Issue 512
------------------------------