Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_5/V15NO598.TXT

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Date: Sat, 26 Dec 92 05:00:03
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #598
To: Space Digest Readers
Precedence: bulk


Space Digest                Sat, 26 Dec 92       Volume 15 : Issue 598

Today's Topics:
                        ** BUSSARD RAMSCOOP **
                          Acceleration, cats
                 Aurora chase planes (was Re: Aurora)
               EVA troubles (Was Re: ground vs. flight
             Justification for the Space Program (6 msgs)
                  Manhattan DISTRICT (not Pr......)
                           SSTO vs. 2 Stage
           Terminal Velocity of DCX? (was Re: Shuttle ...)
             The Real Justification for Space Exploration

    Welcome to the Space Digest!!  Please send your messages to
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----------------------------------------------------------------------

Date: 24 Dec 92 17:18:53 GMT
From: Jason Cooper <[e-mail]>
Subject: ** BUSSARD RAMSCOOP **
Newsgroups: sci.space

Was told to put this message in this area to get more replies, so here
it is.  I'm doing a science fair project on the Bussard Ramscoop, and am
looking for ANY help I can get on the scientific end of it.  I'm looking
for help specifically on the general theory end of it (things like what
polarity the field must be, how best to ionize the hydrogen, how best to
FUSE the hydrogen, etc, all already worked out, but in need of checking
by somebody who KNOWS what they're doing).

                                                        Jason Cooper

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

Date: 25 Dec 92 18:06:59 GMT
From: Bruce Dunn <[e-mail]>
Subject: Acceleration, cats
Newsgroups: sci.space

> John Roberts writes:
>
> I've read that small children often survive long falls with surprisingly
> little injury. It was speculated that they may be more likely to relax
> than adults.
>


        I think that the main cause of differences in the ability of
different creatures to survive falls is our old friend, the square cube law:

        Count a child as having half the linear dimensions of an adult.
Relative to an adult, the "squash room" available for deacceleration is
related to the linear dimension (1/2 of an adult).  If children had the same
body plan as adults, a "half adult size" child would have a mass proportional
to her volume, which is proportional to the cube of her linear dimensions ---
the child would have a mass of 1/2*1/2*1/2 = 1/8 of the adult (real kids hare
probably heavier than this due to the relatively larger sizes of their heads
in the overall body plan).

        Stored energy in a falling body is proportional to mass.  The child
thus has 1/2 the distance for deacceleration, but 1/8 the energy to get rid
of by deformation etc.

        Mice do quite well when dropped a few meters. Dropping an elephant
the same distance would probably create an insurance writeoff.  The
difference is related to body size, not the special body defences that cats
have in addition to their natural size protection (I wouldn't want to drop my
pet lion from the balcony of a 10th story apartment).






--
Bruce Dunn    Vancouver, Canada   [e-mail]

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

Date: 25 Dec 92 20:02:03 GMT
From: Henry Spencer <[e-mail]>
Subject: Aurora chase planes (was Re: Aurora)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Mary Shafer) writes:
>... Remember that flight test, including the chasing, is
>only done by test organizations; operational squadrons (the people who
>routinely fly with weapons) are only rarely involved.  Dryden, for
>example, has absolutely no weapons...

A side issue here is that many people don't understand that weapons are
*dangerous*.  Contrary to what you might think from half-baked war movies,
properly-trained troops treat even hand grenades with great respect and
considerable caution.  Live missiles are dangerous to handle, dangerous
to carry, dangerous to have around.  Even *storing* them safely takes
care and effort.  Aircraft don't fly armed without good reason.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: 25 Dec 92 20:07:19 GMT
From: Henry Spencer <[e-mail]>
Subject: EVA troubles (Was Re: ground vs. flight
Newsgroups: sci.space

In article <j6v2=m#@rpi.edu> [e-mail] (Greg Moore) writes:
>I'd assume the latter, to safe fuel, and to allow it to "float by' if
>something goes wrong.  With a Y+ translation if an 'up" thruster
>(to stop the Y+ movement) fails, you risk running the shuttle into the
>orbiter.  With the X+, if something fails, you just float on by...

The thruster systems are redundant; a single jet failure won't destroy
the ability to maneuver in a particular direction.

>>Leasat repair, the hardware was kept very simple and the astronauts'
>>arms did almost all the work.  (How quickly they forgot these lessons...)
>
>    I don't recall what Leasat was.  Could you give me some private email
>sometime to jog my memory?

(Easier to just include it here, in case anyone else is wondering...)  That
was the "Frisbee launched" satellite, aka Syncom, which couldn't light its
boost motor after deployment from an earlier shuttle mission.

>    It seems like a good argument for satellite manufacturers to include
>a grapple point...

If memory serves, the head of Intelsat has said "henceforth we put grapple
fixtures on our satellites".  Not very likely that there'll be any use for
one any time soon, but it sure does save a lot of hassle when the occasion
does arise.
--
"God willing... we shall return."       | Henry Spencer @ U of Toronto Zoology
       -Gene Cernan, the Moon, Dec 1972 |  [e-mail]  utzoo!henry

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

Date: Fri, 25 Dec 1992 10:13:08 GMT
From: Bill Blum <[e-mail]>
Subject: Justification for the Space Program
Newsgroups: sci.space,talk.politics.space

In article <[e-mail]> [e-mail] (Paul Dietz) writes:
>In article <[e-mail]> [e-mail] writes:
>
> > I will no longer debate you on this subject. You have your "opinions",
> > which is all your responses to date have been, and I have mine. You
> > work for your worldview and we will work for ours.
> >
> > You speak of quasi-religiousness when the exact same thing can be said
> > of your asserations.
>
>Oh, *please*.  I've posted numerous quantitative arguments in rebuttal
>to your claims.  I can even provide references for those numbers, if
>you'd like.

Oh *please*.

Both sides can drag quantitative arguments out of every nook and cranny of
every publication in existence until the rest of USENET dies at their
terminals.

Yes, I believe in space exploration.  I don'T subscribe to the belief that
it is absolutely necessary for survival...I do think that it serves a
purpose, and should be continued.

I believe that there are some amazing possibilities out there, beyond
Earth'S orbit.
I've noticed that many people consider "dreaming" about such things and
working towards it with all we can bring to bear too overzealous.
May I remind some of the skeptics that the Internet itself was the product
of a bunch of people who's sole puropose was to ensure a network by which
NORAD could communicate.   Zealotry pays off in ways you can't imagine in
the short term.


> > I have work to do. I live in the real world. If you actually think
> > things are getting better from a world perspective then you are truly
> > blind. This is a simple fact, not a flame.
>
>By most objective measures, the world is getting better.  The world
>has never been, on average, wealthier, healthier, better fed, or
>better educated than it is today.  These are *facts*.  You can look up
>the numbers.  These trends have been going on for decades, in spite of
>the continuous (and continuously wrong) doomsaying.

Gee, Mr. Dietz.  Go to Somalia.  Talk with the people.  They would strongly
disagree with you about being better off.

It is a FACT that the future is uncertain.
(_Introduction to Nuclear Engineering_, 2nd Edition, John Lamarsh)
-begin quote-
    Whether sufficient uranium will be available to fuel expanding
world nuclear capacity is an issue of continuing controversy even among
experts.  Uranium itself is not an especially rare element.  It is present
in the earth's crust at a concentration by weight of about four parts per
million, which makes uranium more abundant than such common substances as
silver, mercury, and iodine.  There are an estimated 10^14 tons of uranium
located at a depth of less than 12 or 13 miles, but most of this is at such
low concentrations it WILL PROBABLY NEVER BE RECOVERED, (boldface added by
me)
-end quote-

Yes, Mr Dietz, there are abundant supplies of some materials on Earth.
But be nice to the zealots...they occassionally come up with some brillant
ideas which influence a lot of people.  Like the Internet.

Often, zealots lose sight of reality.  YEt just as often, skeptics lose
their clues.

Here's wishing everyone a Merry Christmas, and a Happy News Year, and
(insert any other holiday I missed here).

--
Bill Blum            * "God willing...we shall return."
Purdue University        * Gene Cernan, The Moon, Dec 1972(BSEE P.U. 56)
School of Nuclear Engineering    * Member of the SEDS National Board
[e-mail]     *        Ad Astra Per Ardua!!

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

Date: Fri, 25 Dec 1992 13:03:15 GMT
From: Paul Dietz <[e-mail]>
Subject: Justification for the Space Program
Newsgroups: sci.space,talk.politics.space

In article <[e-mail]> [e-mail] (Bill Blum) writes:

>>By most objective measures, the world is getting better.  The world
>>has never been, on average, wealthier, healthier, better fed, or
>>better educated than it is today.  These are *facts*.  You can look up
>>the numbers.  These trends have been going on for decades, in spite of
>>the continuous (and continuously wrong) doomsaying.

> Gee, Mr. Dietz.  Go to Somalia.  Talk with the people.  They would strongly
> disagree with you about being better off.

What a load of crap.  Of course there are people who are in bad
situations.  But these extreme points prove nothing, except that the
world is not completely perfect.  As I said, ON AVERAGE, the world is
getting better.  Fewer people (in absolute numbers, not just as a
fraction of the world's population) are living in countries that
experience famines that did a generation ago.  On average, people are
getting more nutrition, and living longer.


>It is a FACT that the future is uncertain.
>(_Introduction to Nuclear Engineering_, 2nd Edition, John Lamarsh)
>-begin quote-
>
>    Whether sufficient uranium will be available to fuel expanding
> world nuclear capacity is an issue of continuing controversy even among
> experts.  Uranium itself is not an especially rare element.  It is present
> in the earth's crust at a concentration by weight of about four parts per
> million, which makes uranium more abundant than such common substances as
> silver, mercury, and iodine.  There are an estimated 10^14 tons of uranium
> located at a depth of less than 12 or 13 miles, but most of this is at such
> low concentrations it WILL PROBABLY NEVER BE RECOVERED, (boldface added by
> me)


I cannot imagine what you are trying to prove by this quote.  Let's
consider a world with 10,000 1 GWe reactors.  It will consume
somewhere less than 20,000 tons of uranium per year.  Those 10^14 tons
would last 5 billion years at that rate.

So, indeed, much of that uranium never gets recovered -- because it
decays, or the sun burns out, before we need it!  Note that being at a
depth of 12 or 13 miles doesn't really matter, because we would use it
so slowly that erosion (and isostatic uplift) would move it to the
surface sufficiently quickly.

I understand that if you pulverize granite and wash with acid, about
1/3 of the uranium and thorium can be easily mobilized (the rest could
be recovered by more vigorous treatment).  This fraction eluted from a
ton of granite is equivalent to about 15 tons of coal, if used in some
sort of breeder.  However, no doubt richer deposits will be attacked
first (for example, organic-rich shales; the Chattanooga Shale, for
example, is estimated to contain 5 million tons of uranium at about 60
ppm).

I know of no nuclear experts who think there is not sufficient
recoverable uranium to run a breeder-based economy for far longer than
is reasonable to plan for.  There is some controversy on how long
burner reactors can be fueled without breeding, especially if the
number of such reactors grows.  Fortunately, accelerator breeders
can be used to make fuel for burner reactors, with a doubling time
of about 3 years, so if fuel ever did become unexpectedly short
we could adapt quickly.

    Paul F. Dietz
    [e-mail]

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

Date: 25 Dec 92 17:43:41 GMT
From: Herman Rubin <[e-mail]>
Subject: Justification for the Space Program
Newsgroups: sci.space,talk.politics.space

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

>>>By most objective measures, the world is getting better.  The world
>>>has never been, on average, wealthier, healthier, better fed, or
>>>better educated than it is today.  These are *facts*.  You can look up
>>>the numbers.  These trends have been going on for decades, in spite of
>>>the continuous (and continuously wrong) doomsaying.

>> Gee, Mr. Dietz.  Go to Somalia.  Talk with the people.  They would strongly
>> disagree with you about being better off.

>What a load of crap.  Of course there are people who are in bad
>situations.  But these extreme points prove nothing, except that the
>world is not completely perfect.  As I said, ON AVERAGE, the world is
>getting better.  Fewer people (in absolute numbers, not just as a
>fraction of the world's population) are living in countries that
>experience famines that did a generation ago.  On average, people are
>getting more nutrition, and living longer.

Baloney.  The US economy is in a shambles, and will probably continue
to go downhill.  In real terms, income and incentives are DOWN.  The
universities are giving in to the almost illiterate (at least in
mathematics and the sciences) high school preparation of the students,
and contributing to the demise of our academic and research capabilities.
The government wants to essentially abandon the pure research on which
the future depends.  Our taxes go to pay interest on our mistakes, and
most of the rest goes to encourage incompetence.  The overpopulation of
the world, and also of the US, is increasing at an alarming rate, and
the "politically correct" thing to do is to keep encouraging this to
go on at an even greater rate.  This is by actions, not by words which
nobody listens to.


>>It is a FACT that the future is uncertain.
>>(_Introduction to Nuclear Engineering_, 2nd Edition, John Lamarsh)
>>-begin quote-

>>    Whether sufficient uranium will be available to fuel expanding
>> world nuclear capacity is an issue of continuing controversy even among
>> experts.  Uranium itself is not an especially rare element.  It is present
>> in the earth's crust at a concentration by weight of about four parts per
>> million, which makes uranium more abundant than such common substances as
>> silver, mercury, and iodine.  There are an estimated 10^14 tons of uranium
>> located at a depth of less than 12 or 13 miles, but most of this is at such
>> low concentrations it WILL PROBABLY NEVER BE RECOVERED, (boldface added by
>> me)


>I cannot imagine what you are trying to prove by this quote.  Let's
>consider a world with 10,000 1 GWe reactors.  It will consume
>somewhere less than 20,000 tons of uranium per year.  Those 10^14 tons
>would last 5 billion years at that rate.

But we cannot build nuclear plants which are safer than the coal plants.
And those who do not recognize the value of human ingenuity want us to
waste the time of the productive people by making them wait for public
transportation, and keeping the bright from getting an education by
putting them in classes with the mentally deficient.

Communism may be passe in the former Soviet Union and Eastern Europe,
but some of the worst aspects of it are pervading Western Europe and
the United States.  What else can one call the government blocking of
human endeavor, including going to space?  Name ONE sufficiently large
(to accomplish) country in which the individual with enterprise is not
boxed in by the  socialists who insist that the wealth must be shared.
--
Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907-1399
Phone: [phone]
[e-mail] (Internet, bitnet)
{purdue,pur-ee}!snap.stat!hrubin(UUCP)

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

Date: Fri, 25 Dec 1992 18:28:10 GMT
From: Paul Dietz <[e-mail]>
Subject: Justification for the Space Program
Newsgroups: sci.space,talk.politics.space

In article <[e-mail]> [e-mail] (Herman Rubin) writes:

>>world is not completely perfect.  As I said, ON AVERAGE, the world is
>>getting better.  Fewer people (in absolute numbers, not just as a
>>fraction of the world's population) are living in countries that
>>experience famines that did a generation ago.  On average, people are
>>getting more nutrition, and living longer.

>Baloney.  The US economy is in a shambles, and will probably continue
>to go downhill.

The US economy is growing, not "going downhill".  Manufacturing
productivity is growing smartly.  Moreover, the US is not the world.
Less developed countries can and do use technologies that have already
been worked out by the west; naturally, the tendency is for the
underdogs to catch up, if the mechanisms for wealth creation are in
place.

Consider China.  The private sector there will grow more than 20% this
year, and exceed the size of the public sector; aggregate GNP growth
will be in double digits.  At current growth rates, China's GNP could
exceed the entire OECD's by the year 2010.  The per capita GNP could
reach current US levels within a generation, at current rates of
growth.


>>I cannot imagine what you are trying to prove by this quote.  Let's
>>consider a world with 10,000 1 GWe reactors.  It will consume
>>somewhere less than 20,000 tons of uranium per year.  Those 10^14 tons
>>would last 5 billion years at that rate.

>But we cannot build nuclear plants which are safer than the coal plants.

Bullshit.  Existing coal plants kill more people than existing
nuclear plants, and we can build nuclear plants that have accident
rates much lower than the current generation, low as they are.


> Communism may be passe in the former Soviet Union and Eastern Europe,
> but some of the worst aspects of it are pervading Western Europe and
> the United States.  What else can one call the government blocking of
> human endeavor, including going to space?  Name ONE sufficiently large
> (to accomplish) country in which the individual with enterprise is not
> boxed in by the  socialists who insist that the wealth must be shared.

Capitalism is quite robust, and can create wealth even in unfree
countries, as the example of China demonstrates.  Again, your argument
confuses perfection (a probably unrealizable libertarian utopia) with
progress (a world in which the aggregate statistics are improving).

    Paul F. Dietz
    [e-mail]

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

Date: 25 Dec 92 18:31:01 GMT
From: Joe Cain <[e-mail]>
Subject: Justification for the Space Program
Newsgroups: sci.space,talk.politics.space

Both Drs. Dietz and Rubin have made some good points. I hope the
subject can now be changed to focus more on a specific facet with its
own subject rather than continuing the present one whose thread seems
to be all inclusive. There are now several cross discussions going
with this reference and their own sub-threads.

Joseph Cain        [e-mail]
[e-mail]        scri::cain
Department of Geology B-160
Florida State University

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

Date: Fri, 25 Dec 1992 19:35:21 GMT
From: Herman Rubin <[e-mail]>
Subject: Justification for the Space Program
Newsgroups: sci.space,talk.politics.space

In article <[e-mail]> you write:
>In article <[e-mail]> [e-mail] (Herman Rubin) writes:

>>>world is not completely perfect.  As I said, ON AVERAGE, the world is
>>>getting better.  Fewer people (in absolute numbers, not just as a
>>>fraction of the world's population) are living in countries that
>>>experience famines that did a generation ago.  On average, people are
>>>getting more nutrition, and living longer.

>>Baloney.  The US economy is in a shambles, and will probably continue
>>to go downhill.

>The US economy is growing, not "going downhill".  Manufacturing
>productivity is growing smartly.  Moreover, the US is not the world.
>Less developed countries can and do use technologies that have already
>been worked out by the west; naturally, the tendency is for the
>underdogs to catch up, if the mechanisms for wealth creation are in
>place.

The US economy might be growing in dollar terms, but not in real terms
per capita.  And one does not benefit if others catch up at one's
expense.

Academic salaries are lower in real terms now than 20 years ago, and
the research which drives the future is being curtailed.  The emphasis
on short-term practical results is a vain attempt to keep a reasonable
position, and will soon backfire.

The US now has more government jobs than manufacturing.  The universities
are catering to the ignoramuses coming out of the high schools, and standards
are just about dead.  It is even getting into the doctoral program.  We are
paying far more to clean up the S&L fiasco, produced primarily by the
government, than for all of our space activities.

>Consider China.  The private sector there will grow more than 20% this
>year, and exceed the size of the public sector; aggregate GNP growth
>will be in double digits.  At current growth rates, China's GNP could
>exceed the entire OECD's by the year 2010.  The per capita GNP could
>reach current US levels within a generation, at current rates of
>growth.

Does the world have enough resources for this?  As I have often said
that I consider the US substantially overpopulated for the available
resources available to us, what will happen when China attempts to
get 4 times as much of them?

>>>I cannot imagine what you are trying to prove by this quote.  Let's
>>>consider a world with 10,000 1 GWe reactors.  It will consume
>>>somewhere less than 20,000 tons of uranium per year.  Those 10^14 tons
>>>would last 5 billion years at that rate.

>>But we cannot build nuclear plants which are safer than the coal plants.

>Bullshit.  Existing coal plants kill more people than existing
>nuclear plants, and we can build nuclear plants that have accident
>rates much lower than the current generation, low as they are.

There is a misunderstanding here.  We agree on the safety, but the
political climate will not let those nuclear plants be built.

>> Communism may be passe in the former Soviet Union and Eastern Europe,
>> but some of the worst aspects of it are pervading Western Europe and
>> the United States.  What else can one call the government blocking of
>> human endeavor, including going to space?  Name ONE sufficiently large
>> (to accomplish) country in which the individual with enterprise is not
>> boxed in by the  socialists who insist that the wealth must be shared.

>Capitalism is quite robust, and can create wealth even in unfree
>countries, as the example of China demonstrates.  Again, your argument
>confuses perfection (a probably unrealizable libertarian utopia) with
>progress (a world in which the aggregate statistics are improving).

The world is not better off with 10 billion people making $5000/year
on the average than with 2 billion people making $15000/year on the average.
The first case will not support the individual drive, the exploration, the
aspiration to the stars (any version of this) which the second will.

Short run capitalism is quite robust, but the accumulation of excess wealth
by individuals who will try to do something with it which those individuals,
unfettered by the demands of the populace, feel worthwhile.  Governments
are not capable of doing this except when pushed by the exigencies of
danger to their security or to national pride.  We had better face the
fact that without war we probably would not yet have done much in space,
and without the cold war, not much beyond the technology of the early 1950s.

A famous automobile executive stated that one should lead, follow, or get out
of the way.  Governments cannot lead, except other governments; they do not
know how to follow, and they refuse to get out of the way.  They have enough
clout that only other governments can get around their blocking.  Ours is
now blocking progress on as many fronts as it can manage.

--
Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907-1399
Phone: [phone]
[e-mail] (Internet, bitnet)
{purdue,pur-ee}!snap.stat!hrubin(UUCP)

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

Date: 25 Dec 92 18:59:03 GMT
From: Daniel Burstein <[e-mail]>
Subject: Manhattan DISTRICT (not Pr......)
Newsgroups: sci.space

(note: I tried replying direct to the person who first wrote back
to me, but the system refused to take his address.  A problem
we've all encountered once or twice...)

<numerous message error handling notes deleted...>

   ----- Transcript of session follows -----
554 tffreeba@ivax... The site ivax does not exist in our domain

To: tffreeba@ivax
Subject: Re: numerous/ 1:ASAT 2:Water 3:misquotes
Newsgroups: sci.space
References: <[e-mail]> <1992Dec24.001733.201@ivax>

The bit about calling the process the "Manhattan Project" has become so
entrenched that you have to look har d to find it referred to by it's true
name.

The (unfrotunately) late Isaac Asimov used to comment about this specific
mis-naming frequently in his columns, generally in the science articles he
wrote for Fantasy and Science Fiction.  I'll try to dig up a referenence
or two from my pile.

Other places the correct name appears are pretty rare.  Generally, if you
can find material written or produced immediately after the War, you'll
find proper mention.

For example, the movie "Beginning or the End" which is a
semi-fictionalized documentary of the program has the top people sitting
around the table.  The actor playing General Groves says "You'll be
working on the Manhattan District.  Project 'Y' is uranium purification,
project 'X' is the bomb site."  (this is not the exact quote from the
movie, but the DISTRICT vs. PROJECT distinction is correct)

Or, more recently, NOVA did a segment on SZILARD, one of the prime
scientists in the undertaking.  In the interviews with various
contemporiaries (damn, I forget who they spoke to/with), they constantly
refer to it as the Manhattan DISTRICT.

take care
danny

<[e-mail]>
or
<[e-mail]> <----direct e-mail address

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

Date: Fri, 25 Dec 1992 18:45:27 GMT
From: Bruce Dunn <[e-mail]>
Subject: SSTO vs. 2 Stage
Newsgroups: sci.space

Regarding my comments that a DC-1 used as an upper stage in a two stage
vehicle would be able to survive an engine failure after separation...

> Edward V. Wright writes:
> However, you've overloaded the DC-1 to get that 5x payload capacity
> you talk about.  It's going to be over max takeoff weight.

      I am not quite sure what your argument is.   The following explanation
of takeoff conditions therefore may or may not answer your objections.

      Putting 5 times the payload on a DC-1 used as an upper stage only
raises the gross mass slightly.  A 500 ton DC-1 in SSTO mode with a 10 ton
payload has a total mass of 510 tons.  In two stage mode, the payload is
raised to 50 tons which increases the total mass to 550 tons.  I think you
are arguing that this increased mass makes it impossible to deal with an
engine out or engine start problem.  However, you have forgotten that in
contrast to a ground takeoff, the upper stage of a two stage vehicle is
operating in a vacuum and has increased thrust.  The increase in thrust
depends on the engine expansion ratio and chamber pressure, but might be
something like the 20% or so that the Shuttle SSME experiences in climbing
from sea level to space.  The increased thrust of a DC-1 in two-stage mode
more than makes up for the payload increase.

        If any problems are created by the increased payload, they will be in
the landing phase after an abort from a two stage launch.  Assuming the
payload isn't jettisoned, the landing mass will be roughly double that of am
abort landing of an SSTO DC-1.  This will require beefing up the landing gear
if the DC-1 is used as an upper stage.  In compensation, it would be possible
to eliminate complicated extendible nozzles for the majority of DC-1 engines,
with only a minimum set of engines capable of atmospheric operation in the
event of an abort situation.

>
> Or if you have negative separation, or separation followed by a
> collision, or several other scenarios you need to worry about.
>
> The problems of staging are not nearly as trivial as you make
> them out.


        We have been launching staged rockets for nearly half a century.  I
think the problems of staging, if not trivial, are solvable.  Certainly,
historical evidence indicates that staging is less of a technical challenge
than SSTO operation.

        For Edward and others tracking this discussion, I would like to again
note that I am strongly in favor of the DC-1 SSTO concept.  I am not
proposing that the DC-1 SSTO capability be scrapped, or that a "DC-0" (to use
Greg's nice name) be immediately developed.  I think of the DC-0 as a
potentially useful extension to an existing DC-1 flight program, to be
developed if and only if:

1)  Very large amounts of cargo have to be put into orbit.

2)  A full scale cost study suggests that it is ***clearly*** less expensive
to develop the two stage system than to simply build more DC-1s.

        I am of the opinion that when it gets closer to designing the DC-1,
it would be helpful to keep the two stage concept in mind so that where
possible design decisions favor approaches which would not rule out the later
use of the DC-1 as an upper stage (for instance, using landing gear which
could easily replaced with beefed up derivative rather than integrating the
landing gear deeply into the body).

        Finally, I think that the two stage concept should be kept in mind as
a potential backup strategy should the DC-1 fail to meet its performance
goals.  As I pointed out in a previous posting, an "obese" DC-1 which has
even a zero payload to orbit in SSTO mode still would make a very fine upper
stage for a two stage vehicle.






--
Bruce Dunn    Vancouver, Canada   [e-mail]

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

Date: 25 Dec 1992 20:27:18 GMT
From: Pat <[e-mail]>
Subject: Terminal Velocity of DCX? (was Re: Shuttle ...)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Gary Coffman) writes:
>>their Shuttle.
>
>Nonsense. The Russians have built no space stations and are having
>trouble raising the funds to operate the one they inherited from
>the Soviet Union. Comparing what was done by a command economy using
>what amounts to slave labor to what's done in an open society where
>people expect to get paid fairly for their work is meaningless accounting.
>


a
Consider that the russians/CIS/USSR  built a major space program with
the GNP the size of France.   And by the Way,  unlike the germans, or chinese
i dont believe the russians have ever been charged with using slave
labor.  Now the russians had a strange command economy,  but things still
cost, but there were major problems in distribution.  the russian/SU
economy was sorta like massachusetts meets new york via sweden.

high taxes,  severe rent control and social provision of major services.

SUre,  they didnt pay their scientists what we paid them here,  but they
provided them with housing, medicine, etc.   Also,  the motivation of most
russian space workers was so great,  that they didn't mind the bad conditions.

the problems within the russian system, were of productivity,  design cycle,
and provision of consumer goods.

The chinese use slave labor,  and then sell it over here.  the russians
paid their workers poorly,  and the workers pretended to work.

the gulags were not used as factories to my knowledge.

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

Date: Fri, 25 Dec 1992 10:24:48 GMT
From: Bill Blum <[e-mail]>
Subject: The Real Justification for Space Exploration
Newsgroups: sci.space,talk.politics.space

In article <[e-mail]> [e-mail] (Brian Yamauchi) writes:
>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.

Good point, Brian.

That's like asking "Why flame people on USENET?"  It's just a basic, human
desire.

>
>The major achievement of Apollo was not Teflon.  The major achievement
>of Apollo was putting a man on the moon.
>
A Purdue Graduate, no less! :)
(Sorry..just had to plug my school :) )

>
>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."

Science has produced many things which have resulted in giant leaps in the
quality of life on Earth.  However, one can't take giant leaps without
making some small steps beforehand.
....20 Jul 1969, Mare Tranquilitatis is my favorite example, but, I'm
biased, and according to some people, i'm a "zealot."  :)  Zealots unite!

--
Bill Blum            * "God willing...we shall return."
Purdue University        * Gene Cernan, The Moon, Dec 1972(BSEE P.U. 56)
School of Nuclear Engineering    * Member of the SEDS National Board
[e-mail]     *        Ad Astra Per Ardua!!

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End of Space Digest Volume 15 : Issue 598
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