HDTenEightyP/NetNews huggingface dataset:
From: hall@aurora.physics.utoronto.ca (Chris Hall)
Subject: Re: Aluminum as rocket fuel?
Organization: University of Toronto Physics/Astronomy/CITA
Date: Fri, 1 Jan 1993 20:02:08 GMT

In article <19070@mindlink.bc.ca> Bruce_Dunn@mindlink.bc.ca (Bruce Dunn) writes:
>
>        Paul Deitz has pointed out in E-mail to me that molten aluminum would
>be an ideal candidate for pressure feeding.  Relative to normal fuels such as
>hydrogen (density 70 kg/m^3) and RP-1 (density 800 kg/m^3), aluminum with a
>density of about 2700 kg/m^3 will require small tanks.  The tanks are very
>hot, meaning that little mass of pressurization gas will be needed.  A useful
>technique might be to have the molten aluminum stored in a spherical steel
>tank pressurized by injecting liquid nitrogen into the tank (which because of
>the heat will immediately vaporize).  Is nitrogen available from the moon?
>
A better choice of pressurizing gas might be helium or argon. Both are inert
and helium is present in reasonable quantities from the solar wind impacting
in the lunar soil. But argon is also present, particularly in old KREEP
deposits, since there has been a considerable length of time for 40K to
decay into 40Ar.

Chris Hall
Chris.M.Hall@um.cc.umich.edu
From: 0004244402@mcimail.com (Karl Dishaw)
Newsgroups: sci.space
Subject: Aluminum as rocket fuel?
Date: 31 Dec 92 00:16:28 GMT
Article-I.D.: cs.C03Krw.88z.1
Distribution: sci
Organization: [via International Space University]
X-Added: Forwarded by Space Digest
Original-Sender: isu@VACATION.VENARI.CS.CMU.EDU

> For final injection, it occurs to me that using gaseous oxygen to "blow"
> the powdered aluminum in might be an option.

We concentrated on not letting the fuel and oxidizer mix outside the 
combustion chamber for safety reasons.  That scrapped LOX slurries and 
blowing the powder.  Another project team sprayed molten steel over a 
blast chamber when their methane/oxygen rocket accidently 
mixed propellants in the feed lines, which makes me feel pretty 
strongly about the safety criterion.

>
>What are the problems with using molten aluminum sprayed into the reaction
>area?  Keeping the aluminum molten in a vacuum should be relatively easy.

What are the weight and power penalties for keeping a tank of molten 
aluminum on your spacecraft?  Could be expensive.  But we kicked 
around some far-out ideas too--shaping the Al into fine wire and 
burning it off a spool or as a "wool", or feeding the power in through an 
airlock and burning it in pulses.

>Another source of information is the External Tank Study published
>by the Space Studies Institute. Cutting up ETs for their aluminum
>was listed as an option. Impulse of such an engine would be in the
>330 second range. Very viable as a Lunar based fuel source.

Is that for a pure Al/O2 engine?  The ETs have leftover H2 on board, 
which SSI might've been including.  The exhaust has to be almost all O2 
or the energy will be absorbed by the oxide particles with very little 
thrust resulting.  My 118 sec Isp calculation was for about 4% 
aluminum in the mass flow.


Karl
sold my soul to Uncle Sam . . . now marked down for resale.
Newsgroups: sci.space,talk.politics.space
From: dietz@cs.rochester.edu (Paul Dietz)
Subject: Re: Justification for the Space Program
Organization: University of Rochester
Distribution: usa, world
Date: Sun, 27 Dec 1992 20:59:45 GMT

In article <Bzxn27.KLA@mentor.cc.purdue.edu> hrubin@pop.stat.purdue.edu (Herman Rubin) writes:

> For others to catch up, we have to stand still.

Perhaps after remarks like this, Herman will be less strident in his
criticisms of the innumerate.

	Paul F. Dietz
	dietz@cs.rochester.edu
Newsgroups: sci.space
From: MSTACK@u.washington.edu (Mike)
Subject: ADVICE ON PAPER TOPIC
X-Added: Forwarded by Space Digest
Organization: [via International Space University]
Original-Sender: isu@VACATION.VENARI.CS.CMU.EDU
Distribution: sci
Date: Tue, 29 Dec 1992 23:59:02 GMT

This is a total blind shot; your name was on a Sept 92 list of current
usenet/Internet lists.  I'm a new user.  I'm writing a concept paper
(does not need to be overly technical--it's more "what if") on the
possibility of unmanned autonomous vehicles (in the future) that can
be launched from space (possibly many garaged on a platform) to do
sensor passes, etc. over crisis areas--the paper is for the Naval War
College Continuing Education program in national security decision-
making.  Topic might involve aerodynamic feasibility, robotics, AI,
and other concerns such as "why do this when we have satellites."
I'm writing to you because you might know some points or questions I
should consider based upon space probes for Venus, Mars, etc.--or, whom
else I should write to on Internet etc.  Appreciate any help you can
give me as NWC isn't offering any.  As background, I spent 2 years in
the navy as an aerospace psychologist, 5 yrs at SAIC doing human-computer
interface design on Suns, and now am a senior policy analyst for info
policy for the state of Washington.  Phone:  206-664-8128 (wk).
Newsgroups: sci.space
From: aws@iti.org (Allen W. Sherzer)
Subject: Re: Stupid Shut Cost arguements (was Re: Terminal Velocity
Organization: Evil Geniuses for a Better Tomorrow
Date: Wed, 30 Dec 1992 20:59:40 GMT

In article <72597@cup.portal.com> BrianT@cup.portal.com (Brian Stuart Thorn) writes:

>>Considering that there are no heavy payloads to return to Earth, this
>>cannot be considered an advantage. Especially for the billions it costs
>>us.

>    GRO and UARS are both candidates for return to earth. 

Doing that would cost more then they are worth. It would be cheaper to
build new ones and launch them commercially.

>    LDEF and

LDEF would have been better flown as a series of smaller platforms.
Under those conditions it would be simple to build a vehicle which
returns them to Earth. That way each experimenter would get custom
time on orbit and the taxpayers would save billions.

>    The Hubble repair could still prove too much for orbiting
>    astronauts and thus require return to Earth for mirror replacement,

No for two reasons: 1) it would be cheaper to build another and fly it
and 2) in testimony before the House the program manager said Hubble
wouldn't survive the return trip.

To date there are no payloads which can be returned by Shuttle in a
cost effective manner.

>    All I'm saying is that Shuttle
>    did not meet its objectives, so don't be so sure about DC.

Same old arguement. I guess Boeing better cancel plans for the 777.
After all, Shuttle failed so 777 will as well.

>    A few weeks ago I mentioned one way that we could have kept some of
>    that market in the U.S. until NLS, DC or whatever was ready. You
>    said that it (maintaining Shuttle launches of commercial payloads)
>    was too costly. Maybe so (definitely so) but those subsidies would
>    have at least kept customers in the U.S. 

And at the same time killed any chance of a sustainable independent
commercial effort. If your going to do that it would be cheaper to
simple end all space activity.

>    Why wasn't DC-X built in 1983

You mean when the government was spending billions killing competition
with Shuttle subsidies? You can't be serious; who would be that stupid?

>    your argument that the next generation of boosters be a commerical
>    endeavor? What is it they say about building a better mousetrap?

It is hard to convince investors when they see that the largest customer
doesn't care about cheaper costs.

  Allen

-- 
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  aws@iti.org     |  nothing undone"                                       |
+----------------------115 DAYS TO FIRST FLIGHT OF DCX----------------------+
Newsgroups: sci.space
From: sbooth@lonestar.utsa.edu (Simon E. Booth)
Subject: Re: I thinI see our problem. (Was Re: Terminal Velocity of DCX?
Organization: University of Texas at San Antonio
Date: Sun, 27 Dec 1992 07:07:50 GMT

In article <ewright.725129915@convex.convex.com> ewright@convex.com (Edward V. Wright) writes:
>In <!jt240c@rpi.edu> strider@clotho.acm.rpi.edu (Greg Moore) writes:
>
>>	In reality it sounds more like you are talking about DC-10,
>>DC-12, etc.
>>	Unless you are saying that a 747 is the same plane as a DC-3
>>was.
>>	If your claims are about 50 years from now, or even 20
>>eyars from now, I'll buy them.
>
>I think it would do you a world of good to go out to your local
>airport and look around.
>
>Do you have any idea how many DC-3s are still flying?  After 50
>years?
>
>And the 747, which you cite as an example of a modern airplane,
>is well over 20 years old!
>
And don't forget the G and H model B-52'as.  Those are at least 30 years
old and still flying.
I think I read somewhere that many old planes are so durable that the primary
problem in keeping them flying isn't how well they were designed but
maintaining a supply of spare parts (i.e. WWII aircraft still flyable today).

Supposedly this is a similar problem for the shuttle--only 5 flight
capable orbiters built in past 13 years makes a very rare craft, and thus
creates a maintainence problem due to their limited numbers.

Simon

Newsgroups: sci.space
From: dietz@cs.rochester.edu (Paul Dietz)
Newsgroups: sci.space
Subject: Re: Breeder reactors
Date: 21 Dec 92 18:10:18 GMT
Distribution: sci
Organization: University of Rochester

In article <BzMDJq.2KJ.1@cs.cmu.edu> 18084TM@msu.edu (Tom) writes:

> Maybe it's just as well.  The way I heard it, France is already reaching
> the point where the costs are becoming dominated by uranium ore
> recovery, as it gets rarer & rarer.  And they've had nukes for what,
> 15 years?  That's pretty short, especially considering all the other
> high-tech-costs in reactor operations.

You heard wrong.  Uranium prices are so depressed that mines are
closing.  Spot market price is around $10/pound; the U-235 in one
pound of uranium can produce about 20,000 kWh of electricity.  It
could increase in price by a factor of 20 or more and still not
dominate costs.

	Paul F. Dietz
	dietz@cs.rochester.edu
From: roberts@cmr.ncsl.nist.gov (John Roberts)
Newsgroups: sci.space
Subject: Re: Comparative $/lb to LEO
Date: 31 Dec 92 03:36:16 GMT
Distribution: sci
Organization: National Institute of Standards and Technology formerly National Bureau of Standards
X-Added: Forwarded by Space Digest
Original-Sender: isu@VACATION.VENARI.CS.CMU.EDU


-From: ewright@convex.com (Edward V. Wright)
-Subject: Re: Comparative $/lb to LEO (Was: Stupid Shuttle Cost Arguments)
-Date: 29 Dec 92 17:11:40 GMT
-Organization: Engineering, CONVEX Computer Corp., Richardson, Tx., USA

-That said, there are some launchers that cost more, per pound
-of payload on orbit, than the Shuttle.  But they are very small
-launchers that don't have many pounds of payload to spread
-their cost across.

Well said. The Shuttle has some good points, but cost isn't one of them.

The advantages of the small, high $/lb launchers are low cost for a 
dedicated launch, and reducing the time spent waiting for a launch
(at least in theory - Pegasus has to increase its launch rate if it
wants to serve that market).

If DC is successful, the small launchers may have to adjust their market
niche (or their prices).

John Roberts
roberts@cmr.ncsl.nist.gov
From: dietz@cs.rochester.edu (Paul Dietz)
Newsgroups: sci.space
Subject: Re: SSTO vs 2 stage
Date: 31 Dec 92 18:23:58 GMT
Article-I.D.: cs.1992Dec31.182358.13827
Distribution: sci
Organization: University of Rochester

In article <ewright.725820847@convex.convex.com> ewright@convex.com (Edward V. Wright) writes:

> Oh?  Well, let me try again.  The main cost component for reuseable 
> launch vehicles is not fuel, or even fabrication costs, but maintenance.  
> This is even more true for space launchers than for aircraft.  Bruce
> offered a careful and thoughtful analysis that would reduce fabrication 
> and fuel costs (*if* you accept his handwaving assertion that the lower
> stage would cost less per pound to manufacture) while enormously increasing
> the already-greater maintenance costs.


No, he showed that for the cost of maintaining twice the number of
stages, you get about 5 times the payload (the same scheme with
airliners would not give a 5x increase in payload, which shows the
problem with the analogy).

You are apparently tossing in the assumption that stacking will be
very expensive.  This assumption may very well be true, but you have
not justified it.

You have also not brought out the best argument: that TSTO has higher
development cost.  Indeed, even Bruce does not suggest that TSTO be
pursued instead of SSTO, but be kept as a backup or as a follow-on.

	Paul
Newsgroups: sci.space
From: gary@ke4zv.uucp (Gary Coffman)
Subject: Re: DC vs Shuttle capabilities
Reply-To: gary@ke4zv.UUCP (Gary Coffman)
Organization: Destructive Testing Systems
Date: Fri, 25 Dec 1992 00:54:51 GMT

In article <1992Dec22.182600.29193@iti.org> aws@iti.org (Allen W. Sherzer) writes:
>In <ggm2ljr@rpi.edu> strider@clotho.acm.rpi.edu (Greg Moore) writes:
>
>>	I think we differ big-time when it comes to DC-1.  Allen seems
>>to me to be saying, "Things will work out, and this is how it will be."
>
>From a technical point of view I am saying that a fully reusable SSTO
>vehicle carrying a reasonable payload (10 to 20 K pounds) and operational
>costs of $10 to $29 million per flight *CAN* be built with available
>technology. I also believe that operational costs can drop to $1 to $5
>million range if utilization is high enough.
>
>I believe this partly from my own assessment and the fact that every
>assessment done has concluded that it is possible. Even the internal
>NASA assessment say it can be done and that it could save billions.
>
>Now this doesn't mean that DC-Y WILL work. The biggest problems however
>are managerial, not technical. Using conventional government procurement,
>it will be impossible to build SSTO. Using a commercial like process however
>should work.

Finally, an intelligent position on SSTO from Allen. I would quibble,
however, that while there are no known *theoretical* technical issues
unresolved, there remain numerous practical technical problems to 
solve in the DC program. DC is a complex technical vehicle, even if
it is designed to be much simpler than Shuttle, and like any complex mechanism, 
teething problems are almost certain to arise. That's the type of contingency 
for which less optimistic management systems provide alternative actions
and funding. Whether McDD and any government sugar daddies they can attract 
will be willing to continue to fund them through the inevitable setbacks 
remains to be seen. I also suspect that cheaper alternatives to SSTO are 
technically possible with MSTO expendibles for some missions, though whether 
anyone will build them remains unknown. I wish McDD luck, but ask that they 
stay away from Hartsfield International until they've developed a good track 
record of operations.

Gary

-- 
Gary Coffman KE4ZV          |    You make it,     | gatech!wa4mei!ke4zv!gary
Destructive Testing Systems |    we break it.     | uunet!rsiatl!ke4zv!gary
534 Shannon Way             |    Guaranteed!      | emory!kd4nc!ke4zv!gary      
Lawrenceville, GA 30244     |                     | emory!ke4zv!gary@gatech.edu
Xref: sparky sci.space:18105 talk.politics.space:1589
From: det@phlan.sw.stratus.com (David Toland)
Newsgroups: sci.space,talk.politics.space
Subject: Re: The Real Justification for Space Exploration
Date: 23 Dec 1992 13:23:59 GMT
Organization: Stratus Computer, Software Engineering
Distribution: world
NNTP-Posting-Host: phlan.sw.stratus.com

In article <YAMAUCHI.92Dec23004324@yuggoth.ces.cwru.edu> yamauchi@ces.cwru.edu (Brian Yamauchi) writes:
[
It seems to me that all of these spinoff arguments, Malthusian
arguments, and "dinosaur killer" arguments miss the point.

Asking "why explore space?" is like asking "why feed the starving?",
"why create art?", or "why do basic science?"  It all comes down to
basic human drives, and I would argue that the drive to explore is
just as basic as the drive to help, to create, or to learn.

The major achievement of Apollo was not Teflon.  The major achievement
of Apollo was putting a man on the moon.

When Sir Edmund Hillary was asked why he climbed Everest, he answered,
"Because it's there."  The same answer is just as appropriate for why
we explore space -- because the entire universe is out there...

Yes, there are pragmatic near-term benefits of space commerce, but
most of those don't extend far beyond geosynchronous orbit.  And there
are many long-term benefits likely to accrue from interplanetary space
development, but most of those will be _very_ long-term.

At some level, perhaps the most honest answer to the "why explore
space?" question is the simplest -- "If you have to ask, you'll never
understand."
]

Well put.  However, for those who "don't get it and never will", there
are concrete benefits to proceding and real risks (low probability
but high stakes) to not doing so.

The only real argument I have seen *against* an aggressive commitment to
space exploration and exploitation is the old song that the money could
better be put elsewhere.  I think there's more than enough government
money wasted in economy-sapping transfer payments that could better be
used for a real space program.  That would create jobs in the short
term and stimulate the economy with new technologies in the somewhat
longer term.  This I firmly believe, but I also realize that I am
unlikely to convince those that see a solution in social programs.
I have even been recently been referred to as a zealot (first time
for everything, I guess!).  Well, I have listened to the arguments,
I've simply not been convinced by them.

In any case, make no mistake.  Although I see concrete reasons for
a stronger commitment to space exploration, I am also a dreamer who
wishes he were born at a time when he could walk on sands yet unseen
by any human.


-- 
--------------------------------------------------------------------------
All opinions are MINE MINE MINE, and not necessarily anyone else's.
det@phlan.sw.stratus.com   |  "Laddie, you'll be needin' something to wash
                           |  that doon with."
Newsgroups: sci.space
From: ewright@convex.com (Edward V. Wright)
Subject: Re: DC vs Shuttle capabilities
Date: Tue, 22 Dec 1992 22:08:31 GMT
Organization: Engineering, CONVEX Computer Corp., Richardson, Tx., USA
X-Disclaimer: This message was written by a user at CONVEX Computer
              Corp. The opinions expressed are those of the user and
              not necessarily those of CONVEX.

In <9ls2_fp@rpi.edu> strider@clotho.acm.rpi.edu (Greg Moore) writes:

>	Let's handle baggage transfer.  On the ground, you have gravity
>and the surface.  You can walk/carry/drive between two planes... But in 
>space, you don't have something nice like the ground to use.  

So, you think that gravity makes bagger transfer easier?  Would you
like to carry my suitcases next time I'm at the airport?


>	As for manevouring the 3 craft in close proximity, I partly
>agree with you.  It is easier than doing it in the air.  However,
>you do have three craft now all with somewhat different velocity
>vectors.  

Only if you assume that the pilots are *stupid*.  Otherwise, they'll
match velocity vectors and soft- or hard-dock first.


>	I'm not saying it can't be done, or that it won't be done.
>Simply that some thought and PRACTICE will have to go into it.

You think God told Adam and Eve how to refuel a 747?




Newsgroups: sci.space,talk.politics.space
From: aws@iti.org (Allen W. Sherzer)
Subject: Re: Latest Pegasus news?
Organization: Evil Geniuses for a Better Tomorrow
Date: Mon, 28 Dec 1992 02:17:49 GMT

In article <72487@cup.portal.com> BrianT@cup.portal.com (Brian Stuart Thorn) writes:
>>We may all be thankful that the people at OSC are willing to try things
>>to see if they will work.

>   What do you call the TSS tether experiments this summer? 

I call it another example of good research and development we need more of.

>   Brand new technology that could revolutionize orbital transfer and power
>   generation. 

Exactly.

>   That was those despicable fools at NASA doing this.

here you lost me. You seem to live in a very black and white world. You
assume that since I don't support everything NASA does (even its mistakes)
that I must oppose everything NASA does.

This is not the case. There is lots of great stuff going on at NASA. I
criticize the unproductive things NASA does so that we can have more of
the good stuff. Why does that bother you so much?

>   Just because NASA isn't deep in development of a new space booster
>   (why bother when SDIO already is) 

NASA shouldn't be developing OR operating any operational space transport
system. That is outside its charter and is ultimately wasteful and harmful
to lower cost solutions.

>   doesn't mean that they aren't
>   doing important work. Just about everything they do on the Spacelab
>   missions is the (ahem) dull background work needed before going on
>   to bigger and better things. 

Without doubt. The problem is that you seem to think asking the question: "is
there a cheaper way to do this" is treason. 

As an engineer I ask myself that same question every single day. Why do you
think NASA shouldn't worry about the costs?

>   It's not fair to denounce NASA for
>   laying the foundation while praising OSC and McDAC for erecting the
>   skyscrapers.

Pegasus is the subject of this thread so that is what I mentioned. 

As to denouncing NASA, I praise NASA when they lay the foundation. I
condemn them when they prevent the skyscraper from being built.

   Allen
-- 
+---------------------------------------------------------------------------+
| Allen W. Sherzer | "A great man is one who does nothing but leaves        |
|  aws@iti.org     |  nothing undone"                                       |
+----------------------118 DAYS TO FIRST FLIGHT OF DCX----------------------+
Newsgroups: sci.space