Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_6/V15NO611.TXT

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Date: Wed, 30 Dec 92 05:15:56
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #611
To: Space Digest Readers
Precedence: bulk


Space Digest                Wed, 30 Dec 92       Volume 15 : Issue 611

Today's Topics:
                   "Moonraker" -- fact or fiction?
                            averting doom
                           Comparative $/lb
   Comparative $/lb to LEO (Was: Stupid Shuttle Cost Argum (2 msgs)
                         Latest Pegasus news?
                       Saturn lift capabilities
                           SSTO vs 2 stage
   Stupid Shut Cost arguements (was Re: Terminal Velocity (3 msgs)

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Date: 30 Dec 92 02:26:44 GMT
From: Don Allen <bilver!dona>
Subject: "Moonraker" -- fact or fiction?
Newsgroups: alt.conspiracy,talk.politics.misc,sci.space.shuttle,sci.space,sci.astro

In article <[e-mail]> [e-mail] () writes:
>In article <[e-mail]> [e-mail] (Eidetics Int'l) writes:
>>
>>   In writing his stories, Ian Fleming was drawing upon his own
>>secret weapon.  That weapon was knowledge.  Fleming had been a
>>high-ranking officer of Britain's crack Intelligence agency
>>called MI-5.
>
>    This is, in fact, nonsense.  Flemings contribution to
>    intelligence was to act as a paper-pusher for Stephensons'
>    BSC in New York.  He had no training in, and never was, an
>    intelligence officer of any form.  He was, by all accounts,
>    an irritating little intel.-groupie.
>
>    The rest of this post is nonsense that even Munchhausen would
>    be ashamed to come up with.
>
>    Alec Chambers

Well said :-)

Of course this is nonsense..in fact, these Beter letters are the purest
baloney you'll ever come across..right up there with "Secret ET underground
bases" (show me the evidence) and other such dreck..

It _is_ good for a chuckle or too so I guess we should give the Eidetics
people a hand for entertainment. :}

Don


--
<*> Don Allen <*>             1:363/81.1 - Fidonet #1 - Homebody BBS
[e-mail] - Internet   1:363/29.8 - Fidonet #2 - Gourmet Delight
88:4205/1.1  - MUFON Network  1:3607/20.2  -- Odyssey - Alabama UFO Net
NSA grep food: Aviary, Ed Dames, Los Alamos - Majestic - Jason - RIIA - UN

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

Date: 29 Dec 92 21:10:51
From: John McCarthy <[e-mail]>
Subject: averting doom
Newsgroups: sci.astro,sci.space,sci.physics,sci.environment

from a U.P. story

         WASHINGTON (UPI) -- Life on Earth as we know it will
     come to an end in 1,500 million years and the planet will
     look more like its dusty, volcanic sister Venus in 2,500
     million years, scientists said Wednesday.
         But mirrors or shades potentially could shield Earth
     from increasing heat from the sun and delay the catastrophic
     consequences, they said. A collision with a comet or other
     major change in the atmosphere could speed up the end of
     life.
         Ken Caldeira and James Kasting of Pennsylvania State
     University calculated the doomsday estimates using computer
     models of temperature and atmosphere changes and projections
     of the sun's increasing heat.
         As the sun continues to brighten and warm over time,
     the amount of carbon dioxide in the atmosphere drops --
     eventually to a point too low for plants to survive, the
     scientists said in the British journal Nature.



         ``After 2 1/2 billion years, all of Earth's water
     would have been lost to space. That's a pretty strong
     barrier to life,'' said Caldeira, an Earth systems
     scientist.
         Tyler Volk, an applied science professor at New York
     University, suggested there may be ways to delay or prevent
     the eventual demise of life.
         ``Our descendants or descendant species would not
     have to run from the devolution...they could fight,'' said
     Volk. ``Shades in space or mirrors on the Earth that keep
     out a small fraction of the elevated future (heat from the
     sun) would be an option.''
         Other possible solutions include constructing closed
     environments such as the Biosphere 2 project in Arizona, in
     which cycling of carbon dioxide, water and other essential
     matter would be controlled.  Establishing controlled
     Earth-like environments in space also could be considered,
     Volk said.

(Is it really true that mainly doom-seekers become Earth systems
scientists, and mainly problem-solvers become applied science
professors?)


The most straightforward way to avoid the death of the earth from the
overheating predicted by Caldeira and Kasting is to move the earth
farther from the sun on whatever schedule seems appropriate to our
descendants.

Here's the best way to do it that I have been able to think of.  It is
along the same line as what Thomas Clarke offhandedly suggested in a
reply to my original post.  The present post contains only a
qualitative discussion with a few numbers taken from calculations I
made for a slightly different project - moving Mars closer to the sun
in order to improve its climate.  I need to work on the formulas and
the numbers some more before giving them.

The method involves no new science and only predictable improvement
in present technology.

Our object is to transfer energy from the orbit of Venus to the
orbit of the earth so that Venus will move closer to the sun and
the earth farther away.  Jupiter could also be used.  Unfortunately,
it seems that the matter is a bit more complicated than this, because
the process must not only conserve energy, but it must also conserve
angular momentum of the earth and Venus about the sun.  Maybe this
can be done at the cost of giving Venus a more eccentric orbit, but
maybe it requires a third planet.  (This is analogous to processes
in atomic physics that require a third body in order to satisfy
all the conservation laws.)

The problem is to arrange for a coupling between the orbits of the
earth and Venus and possibly another planet as well.

Our tool for doing this is what I shall call a *tame asteroid*.
A tame asteroid is one that has repeated encounters with planets.
A small deflection of the asteroid's orbit before an encounter
is magnified by the encounter.  The asteroid is always controlled
so that it never stops having encounters.  The deflections
(delta-v s) are accomplished as many encounters in advance as the
noise in the system will permit.

[This process is analogous to the trajectory of the spacecraft
Galileo, but apparently the plan with Galileo is to give up the close
encounters when it enters the Jovian system.  It JPL were to keep
control of it by a sequence of encounters, it could be returned to the
vicinity of the earth after spending sufficient time in the Jovian
system.  I have no idea what use this might be.]

The asteroid, say Ceres, has repeated encounters with the earth
and Venus.  It passes in front of the earth and behind Venus on
each encounter.  Thus it adds energy to the earth's orbit and takes
it from Venus's orbit.

When I was thinking about moving Mars, I made some calculations
involving the masses of Ceres, Mars and Venus and the ratio between
the escape velocity from Mars and the delta-v s needed to move
Mars to the more salubrious distance of the earth's orbit.
I got a figure of at least 330 encounters taking at least about
two years each.  This assumed that each encounter with Mars
transferred the maximum possible amount of energy.  Therefore, the
computation is optimistic by some small factor, say 5.

Since the earth is 9 times as massive as Mars, about 9 times as
many encounters would be required.  At least at first, the encounters
would take less time, because the earth and Venus are closer to the
sun.

The problem with conserving angular momentum is one I only encountered
recently, so I haven't figured out what additional encounters might
be needed.


Keeping a Tame Asteroid Tame

Ceres has a mass of 10^21 kilograms, so it would be important to
make its deflections as much in advance as possible.  I assume that
the gravitational fields of the bodies involved will have been
measured accurately long before the project is attempted, i.e. the
high order harmonics of the gravitational potentials will be accurately
known.  What I don't know is this: What is the largest source of noise, i.e.
unpredictable deflections, in the system?  I speculate that it is
weather in the sun causing unpredictable fluctuations in the sun's
gravitational field.  I don't know if this is right, and I hope someone
else can shed light on how large they are likely to be.


Taming Ceres

I confess I haven't yet computed how large a delta-v must be imparted
to Ceres to tame it.  Making its orbit eccentric enough to cross that
of Mars would suffice, because it could be arranged to encounter Mars
in an appropriate way to tame it.  Besides doing this with a single
delta-v, it would probably be cheaper to put Ceres into a suitable
resonance with Jupiter, so that Jupiter would do the work of making
the orbit of Ceres eccentric enough to tame it.  I don't know how
to do this kind of computation.

The most straightforward way to impart a delta-v to Ceres is to install
a large number of nuclear reactors on it, and use the energy to expel
fragments of Ceres in a desired direction and at an appropriate velocity.
If maximal energy efficiency is wanted, i.e. to impart the maximum
momentum per unit of energy used, then the appropriate velocity is
a simple optimization problem, and it turns out to be  sqrt(2) vec,
where  vec  is the escape velocity from Ceres.  The actual velocity
with which the matter leaves the Ceres gravitational field is then
vec.

The number of reactors needed is large.  A million reactors each
of 1000MWE, would give Ceres a delta-v of 1 km/sec in 1,000 years -
if I did the arithmetic correctly.  If our descendants installed
one reactor every thousand years, they would install a million in
a billion years, and that is time enough to avert the prophesied
doom.  A non-trivial fraction of the mass of Ceres would be consumed
if energy is optimized and if 1 km/sec is needed.  Our descendants
might decide to use a higher exhaust velocity.  More likely, it
will turn out that a considerably smaller delta-v will do with the
aid of Jupiter.  Our descendants might decide to use a smaller
asteroid.


The Broken Kepler Approximation

The full computations required to determine all these trajectories
will be quite large (though within the capacity of present computers).
Moreover, the required information about the gravitational fields
won't be available for a long time.  Here is an approximation that
can give a qualitative picture and an estimate of the time required
to move earth out a given distance or to move Mars in (a shorter time
project).

Make the following assumptions:

1. The planets and the asteroid are point masses.

2. The system is planar.

3. The planets have masses small compared to the that of the sun.

4. The asteroid has a mass small compared to that of any planet
involved.

5. The encounters between the asteroid and a planet are elastic
collisions of point masses.  However, we assume that the possible
angles of the collisions are limited by the radii of the planets.

6. Any individual collision has a small effect on the trajectory
of the planet.

7. The asteroid departs from each collision with a velocity that
ensures a subsequent collision with the same or a different planet.

Making these assumptions leads to the following conclusions.

1. The trajectory of the asteroid is a sequence of segments of
Keplerian ellipses about the sun.  That's why we call the above
set of assumptions the broken Kepler approximation.

2. The segments are separated by elastic collisions with the planets
conserving energy and momentum.

3. For each collision there is a discrete set of deflections that
ensure subsequent collisions.  They form a sort of spectrum.

4. Computing the next collision does not require the solution of
differential equations.  Instead one has transcendental equations
to solve analogous to Kepler's equation (the one used to compute
the position of a planet as a function of time).  However, it
looks like the transcendental equation will involve two unknown
parameters instead of the one that appears in Kepler's equation.

It would be nice to have a program that would compute broken
Kepler trajectories and display them for our contemplation.


I hope I have convinced you that our distant descendants can
survive the warming up of the sun until it becomes an actual
nova.

By the way, it seems to me that if the above idea is sound, it settles
the question of the stability of the solar system - in the negative.
Very likely an asteroid could be tamed over a sufficiently long time
with as small an expenditure of delta-v as might be desired.  Once
tamed it could be used with infinitesimal external force to expel a
planet from the system.  This tells us that the current trajectory of
the solar system is arbitarily close to one in which a planet is
expelled.  Of course, the probability that a planet actually would be
expelled by this mechanism in some particular finite time is extremely
low, because maintaining the required sequence of encounters requires
an improbable precision in the initial conditions.  I suppose a lower
bound on the probability could be computed and from it an expected
upper bound on the gravitational lifetime of the solar system could be
obtained.

Criticism and comments are welcome.  For a certain reason, I even
welcome comments, however uninformed, to the effect that the whole
idea is preposterous.  I prefer such comments to be postings rather
than email.

What would be most welcome is a collaborator on a paper that could
be published in _Nature_.
--
John McCarthy, Computer Science Department, Stanford, CA 94305
*
He who refuses to do arithmetic is doomed to talk nonsense.

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

Date: Wed, 30 Dec 92 00:41:18 EST
From: John Roberts <[e-mail]>
Subject: Comparative $/lb

-From: [e-mail]
-Subject: Re: Comparative $/lb to LEO (Was: Stupid Shuttle Cost Arguments)
-Date: 29 Dec 92 16:31:24 GMT

-The Space Shuttle is the most expensive launch vehicle (per pound in orbit)
-that exists today. I believe this, but cannot prove it.
-...
-However, I freely that I hold this opinion largely on the basis of a gut
-feeling, rather than the available numbers.

Please inform your gut :-) that such comparisons are not very useful unless
accompanied by lots of substantiating math. The markets for Shuttle and
Pegasus are different anyway. The "cost per pound" of launching a KH-12
by Pegasus would be pretty impressive. :-) On the other hand, direct
Shuttle launch to polar orbit would be pretty expensive, since the
Vandenberg facility is mothballed.

Dennis has pointed out (but nobody else seems to believe) that there are
many ways of figuring cost, based on your application - marginal cost of
a single flight, operational costs, operational plus development for
future launches (which is what's usually used for the Shuttle), and
operational plus amortization of all development costs. There's not a
single number you can point to and say "that number is the cost - use it
for all accounting".

John Roberts
[e-mail]

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

Date: 30 Dec 92 05:14:12 GMT
From: Brian Stuart Thorn <[e-mail]>
Subject: Comparative $/lb to LEO (Was: Stupid Shuttle Cost Argum
Newsgroups: sci.space

>Maximum payload weight for a safe abort is
>40,000 lbs, and the shuttle rarely carries that much weight.

     Not true in either statement. 40,000 lbs. is about the average, if I
     reckon correctly. However I'll have to dig up copies of the Shuttle
     Press Kits for each mission to get an accurate figure. Many missions
     have been above the 40,000 lb. mark (STS-29, STS-30, STS-34, STS-41,
     STS-37, STS-43, STS-44, STS-50, all since return-to-flight.) Many of
     the military missions used the IUS, making them candidates for
     40,000+ payloads. The next 40,000+ mission is in two weeks: STS-54.

     The "abort" figure you cite appears to be based on the safe return
     weight (about 35,000lbs) but this has not been a factor in limiting
     Shuttle payload capacity, as the above examples testify.

     -Brian

-------------------------------------------------------------------------
Brian S. Thorn                                    "If ignorance is bliss,
[e-mail]                               this must be heaven."
                                                -Diane Chambers, "Cheers"
-------------------------------------------------------------------------

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

Date: 30 Dec 92 05:13:33 GMT
From: Brian Stuart Thorn <[e-mail]>
Subject: Comparative $/lb to LEO (Was: Stupid Shuttle Cost Argum
Newsgroups: sci.space

>(Note: shuttle fleet average performance to 150 nmi, 28.5 deg circ
>orbit is actually about 56,000 lbs -- so, again I'm being
>conservative about shuttle cost $/lb)

> Wales Larrison                         Space Technology Investor

  Please provide data showing Shuttle average payload as 56,000 lbs.
  Please note that your 'average' figure is higher than the official
  NASA 'greatest' payload. According to the NASA "1991 in Review"
  the heaviest Shuttle mission was STS-43 in August, 1991. The payload
  for this mission was approx. 46,500 lbs. (28.5 inc, 160 mile alt.)

  -Brian

-------------------------------------------------------------------------
Brian S. Thorn                                    "If ignorance is bliss,
[e-mail]                               this must be heaven."
                                                -Diane Chambers, "Cheers"
-------------------------------------------------------------------------

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

Date: 30 Dec 92 04:07:13 GMT
From: Craig Keithley <[e-mail]>
Subject: Latest Pegasus news?
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Brian Stuart
Thorn) wrote:
>
> >>   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.
>
>      I went off the deep end on that one and hereby apologize, Allen.
>      Maybe it's because I don't recall you ever saying a kind word about
>      NASA or one of its programs.
>
> >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?
>
>      Because very seldom does anyone ever mention the great stuff
>      going on at NASA.
>
> >>   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.
>
>      Agreed but with one exception. Presently there is no means other
>      than Shuttle to send people into space. When MacDac or someone
>      else develops a system to send people into space, and a new firm
>      or organization gets going to do the dirty work of launching, then
>      and only then will I be in favor of kicking NASA out of the manned
>      space transportation arena.
>
> >The problem is that you seem to think asking the question: "is
> >there a cheaper way to do this" is treason.
>
>      No, I think that urging the elimination of our only manned space
>      transport system before a proven replacement is available is
>      contrary to the cause of space exploration and development. When
>      someone shows me that they have a workable, cheaper manned space
>      system, then I'll go along with them. But remember, Space Shuttle
>      looked cheaper and faster than the alternatives early in its
>      design phase, too. The transition from paper to flight article
>      seems to have a serious negative effect on launch systems. Asking
>      if there is a cheaper way to do this is a good idea. Saying, "this
>      system which we plan to fly in five or six years definitely will
>      be cheaper than Shuttle" must be carefully considered.
>
> >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.
>
> >As to denouncing NASA, I praise NASA when they lay the foundation. I
> >condemn them when they prevent the skyscraper from being built.
>
>      But didn't you just say that NASA should not be operating a space
>      transport system? If this is so, then how is NASA preventing private
>      industry from building said skyscraper?
>
>      -Brian
>
> -------------------------------------------------------------------------
> Brian S. Thorn                                    "If ignorance is bliss,
> [e-mail]                               this must be heaven."
>                                                 -Diane Chambers, "Cheers"
> -------------------------------------------------------------------------

Craig Keithley
Apple Computer, Inc.
[e-mail]
"I have absolutely no responsibility in this matter, what-so-ever"

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

Date: 30 Dec 92 05:11:00 GMT
From: Brian Stuart Thorn <[e-mail]>
Subject: Saturn lift capabilities
Newsgroups: sci.space

>A question: was a fully fueled CSM, flown in the ASTP launch inclination,
>capable of reboosting Skylab?  Was it structurally feasible?  If so, when
>was the decision made not to reboost after the AST-part of the mission was
>over?
>---
>Gerald Cecil

  Structurally feasible, yes, at least on the SkyLab side of the dock.
  The TRS was supposed to reboost Skylab using this port.

  The decision not to send an Apollo to reboost SkyLab was made almost
  entirely on the premise that Shuttle would be flying long before
  Skylab deorbited. But Shuttle was late and atmospheric expansion in
  that Solar Maximum was greater than expected. End result: chunks of
  Skylab in the Australian outback.

  -Brian

-------------------------------------------------------------------------
Brian S. Thorn                                    "If ignorance is bliss,
[e-mail]                               this must be heaven."
                                                -Diane Chambers, "Cheers"
-------------------------------------------------------------------------

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

Date: Wed, 30 Dec 92 00:58:37 EST
From: John Roberts <[e-mail]>
Subject: SSTO vs 2 stage

-From: [e-mail] (Edward V. Wright)
-Subject: Re: SSTO vs. 2 Stage
-Date: 29 Dec 92 19:46:24 GMT
-Organization: Engineering, CONVEX Computer Corp., Richardson, Tx., USA

-In <[e-mail]> [e-mail] (Bruce Dunn) writes:
->        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.

-You simply do not understand the difference between a converted
-artillery rocket, which we have been launching for nearly half
-a century, and a single-stage-to-orbit *spaceship*.

-Saying that launch vehicles should be multistaged like ICBMs
-makes as much sense as saying that airplanes should be shaped
-like cannonballs.

There's a very good argument for multistage rockets - it makes the mass
ratio much simpler to manage (see some of the books by Willy Ley).
Unfortunately, it also adds to the complexity and reliability problems of
the launcher, which is why we'd like to go to SSTO if we can. Thanks to
advances in technology, it may now be practical, and DC will be a great
breakthrough if it works. But that doesn't mean designers were foolish to
use multistage systems in the past - and some applications, such as direct
flight to the moon without refueling, will probably remain unattainable by
SSTO for a long time.

What Bruce is proposing is in part a way to save the situation if SSTO DC
turns out to be *not quite* practical, or if at some point we want to use
DC hardware to put large payloads into orbit without building a large DC.
His argument *supports* further development of DC.

John Roberts
[e-mail]

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

Date: 30 Dec 92 05:10:24 GMT
From: Brian Stuart Thorn <[e-mail]>
Subject: Stupid Shut Cost arguements (was Re: Terminal Velocity
Newsgroups: sci.space

>All of which is irrelevent.  The Shuttle's design goal was to reduce
>the cost of space transportation.  Its size, reuseability, etc. were
>features decided on to meet that goal.  But instead of reducing costs,
>the Shuttle increased them.
>
>It is a failure.

  Size was increased to accomodate the military, not meet the reduced
  cost goal (and you call me a revisionist!) Reusability was and still
  is considered critical to meeting the low-cost objective. That payload
  return is a capability seldom used is beside the point. That the
  Shuttle is a failure is certainly true, as long as you believe Shuttle's
  only purpose was to haul cargo into LEO cheaply. I do not agree, and
  the presense of astronauts aboard certainly points to something else
  being a very highly-regarded design goal.

>>  Shuttle is also as much a technology demonstrator as it is a launch
>>  system.

>I see you've graduated from the Gary Coffman School of Historical
>Revisionism. :-)  The Shuttle was not designed as a technological
>demonstrator, but an operational vehicle.  If there was a technology
>demonstrator for the Shuttle program, it would be the X-15 or X-24.

    See above reply regarding revisionism. X-15 is a program very
    distantly related to the Shuttle, and it's goals were to expand
    the high speed, high altitude flight regime. That in doing so it
    gave NASA alot of information to use when designing Shuttle was
    just good luck, but the USSR flew their Shuttle without ever
    building an X-15 clone. HL-10/M2-F2/X-24 are certainly related
    to Shuttle, but they only demonstarted the landing portion of the
    technology, and the wingless lifting body was not used, anyway.

>Yes, to "failure-oriented" managers, the fact that a project failed
>is always beside the point.  (After all, don't we expect every
>project to fail?)

    Only when dealing with technology that has never been done before,
    such as the reusable spaceship. Twelve years after maiden flight
    and still nobody else has done that.

    -Brian

-------------------------------------------------------------------------
Brian S. Thorn                                    "If ignorance is bliss,
[e-mail]                               this must be heaven."
                                                -Diane Chambers, "Cheers"
-------------------------------------------------------------------------

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

Date: 30 Dec 92 05:12:05 GMT
From: Brian Stuart Thorn <[e-mail]>
Subject: Stupid Shut Cost arguements (was Re: Terminal Velocity
Newsgroups: sci.space

>In article <[e-mail]> [e-mail] (Brian Stuart Thorn) w
r
>ites:
>
>>   Now I'm totally confused, Allen. Wasn't this discussion about the
>>   Shuttle's launch rate? I thought that you previously belittled a
>>   25% increase in launch rate, to which I took exception.
>
>Sorry for the misunderstanding. No, I suspect 10 flights a year is possible.
>I doubt 12 can be done without MAJOR changes.
>
>But given the very poor record of Shuttle performance to schedule, I assert
>the burden of proof is on you to show 12 can be done. I'll accept any two
>consecutive calendar years with 24 launches.

     One year doesn't go a long way statistically, but 1992 had a pretty
     good record. Only two launches were late according to the Jan 1992
     launch schedule (STS-45 one day late in March, STS-53 two weeks late
     -due to Discovery's maintenance period- in Nov-Dec.)

     Agreed, the proof is in the pudding. Alas, political pressures being
     what they are, NASA is unlikely to get the chance to prove it. Will
     sixteen launches in two years at least give you some cause to believe
     that Shuttle is not yet working at maximum capacity? By the way,
     if Endeavour flies on January 13, that will be nine launches in a
     twelve month period.

>>   I'm still waiting for your explanation as to
>>   why 25% is a good increase for one, but not another.
>
>A DC is simple and reliable enough that 50 flights a year is reasonable
>with the specified ground crew. At 10 flights a year a DC ground crew
>has lots of idle time so not only are more launches possible, they
>will also work to lower costs. Increasing utilization by 25% should
>be no problem (if DC works).

     Essentially the same thing was said in 1972 regarding Shuttle.
     It wasn't true then, but this is the first time I've ever seen
     you use the phrase "if DC works". Heretofor it has been "there's
     no reason it won't work." I've no objection to DC trying, but
     until MD proves it works, let's use what we have to it's utmost
     abilities.

>With Shuttle, 10 flights a year utilized everything pretty much 100%.
>Adding more flights under these conditions means that costs must go up.

     As you just said, ten per year is 100% of Shuttle's capacity without
     raising costs. So why is Shuttle flying only eight times per year?
     THAT is my complaint.

>>   it is very difficult to compare
>>   Shuttle with the expendables
>
>Nobody puts people into space just for the hell of it. They are there to
>perform tasks. Given that, one can ask what those tasks are and wonder
>if there are cheaper ways to do those tasks. We can also decide if the
>tasks are worth doing at the price we must pay.

     That is the argument used to justify cancellation of all manned
     space activities. Is that what you are suggesting, Allen?

>I assert that there are no payloads which must fly on Shuttle and are
>worth flying. If you are going to disagree, please do so with a cost
>analysis or your arguement will be meaningless.
>
>Don't you see the damage you are doing to manned space here? Manned space
>is seen as a boondogle and nothing more than a jobs program for aerospace.
>Your astatements that Shuttle must fly regardless of cost only reenforces
>that view. You are making it easier for our opponents to harm us.

     Your claims as to DC's performance before the thing ever flies
     doesn't wow the public, either. I pointed out four recent high
     tech space programs that failed to meet their goals. Besides,
     unless we go buy Soyuz from Russia, what options do we have?
     Please note that I don't support half-empty Shuttles like STS-52,
     or lofting potentially profitable payloads like LAGEOS, but I
     would not be averse to seeing two more Spacelabs on next year's
     schedule instead of being flightless in May/Jun and Sept/Oct.

>>   ratings show Shuttle to be the most powerful launch system in the
>>   free world. Depending upon whom you ask, it's either alot more capable
>>   than Titan, or just a little.
>
>There isn't a payload in existance today which can't go up on either.

     Some people say GRO and Hubble are examples, I'm not sure. I've
     seen so many figures for both arguments that I don't know which
     to believe anymore. No single payload is beyond Titan, but Shuttle
     generally flies at about 2/3 capacity. So add another payload.

>As to being more powerful, only if you are spending somebody else's
>money.
>
>>   Only the DC is presently envisioned to have more or less the same
>>   attributes as Shuttle, and we both know there is no way Shuttle can
>>   ever compare favorably to a paper launch system.
>
>This is bogus. By this arguement nothing new should ever be built. If
>you have specific complaints about DC, state them. The arguement 'well
>all projects have problems therefore DC will have problems and therefore
>it won't work' is bullshit.
>
     I see your point, but by the same token you can draw up a nuclear
     powered, seven stage behemoth which could place a few hundred tons
     into LEO. Then you can dig up Delta facts and figures and justify
     its construction.

     Specific complaints... I touched on it in the last post. The RL-10.
     You say its simple (a term never before used to describe cryogenic
     powerplants.) I saw beware.
     Ask Russia, which only recently acquired the technology. Ask the
     Japanese, which just postponed H-2 a year because of problems
     with cryogenic engines. Ask Arianespace, most of whose failures are
     due to their cryogenic third stage engine.
     Not a valid argument, you say, because RL-10 has been around since
     the 60s. Okay. In the mid-eighties, General Dynamics began work on
     a Centaur derivative for the Shuttle. P&W also began work on uprated
     RL-10s. This was a proven engine on a proven upper stage. Shouldn't
     have been too much trouble... but it failed twice in eighteen months
     after these modifications. Now MD intends to put an RL-10 on an
     entirely new booster. This MUST require at least as much modification
     as the uprated Centaur. Therefore... prepare yourselves for trouble!
     In the case of the Centaur failures, 50% of the engines failed in
     flight (one of two).
     I am not opposed to DC development, only its proponents who insist
     that its going to be the greatest thing since sliced bread.

>>   Pegasus was new and revolutionary too, and it has spent the past
>>   eighteen months sitting in an assembly plant.

>More of the same; I'll bet you $50 that it starts flying regularly. Well?

     I'm sure it will too, my point is that it wasn't easy getting there.
     You persistently tell us it will be for DC.

     -Brian

-------------------------------------------------------------------------
Brian S. Thorn                                    "If ignorance is bliss,
[e-mail]                               this must be heaven."
                                                -Diane Chambers, "Cheers"
-------------------------------------------------------------------------

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Date: 30 Dec 92 05:12:54 GMT
From: Brian Stuart Thorn <[e-mail]>
Subject: Stupid Shut Cost arguements (was Re: Terminal Velocity
Newsgroups: sci.space

>In article <[e-mail]> [e-mail] (Brian Stuart Thorn) w
r
>ites:
>
>>  Space Shuttle is also the only system designed to be used repeatedly,
>
>The design goal was to build a vehicle which would provide cheap, routine
>access to space. Reusability was simply the method selected. Shuttle failed
>all of its major objectives.

    I would add the word 'manned' to that first sentence. Don't forget
    this unique capability.

>>  is the only system capable of returning very heavy payloads to Earth,
>
>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. LDEF and
    EURECA already did/are flying. EURECA is the biggest satellite
    yet built outside the US or USSR.

    The Hubble repair could still prove too much for orbiting
    astronauts and thus require return to Earth for mirror replacement,
    although this is unlikely. The decision not to return heavy payloads
    is not an engineering decision.

>>  Shuttle is also as much a technology demonstrator as it is a launch
>>  system.
>
>Not according to NASA. To them Shuttle is *THE* Space Transportation
>System. To them it is an operational vehicle.

    True enough, but it was a Space Transportation System which used
    technology and ideas never before flown. It was as much a new way
    of thinking as the DC is today. All I'm saying is that Shuttle
    did not meet its objectives, so don't be so sure about DC.

>>  That the technology proved to costly to replace the expendable
>>  market is beside the point.
>
>Execpt that it's function WAS to replace expendables.

    No it wasn't, that came along because NASA had to justify the
    Shuttle's existence. They would have been perfectly happy
    flying only Spacelabs and building Freedom, but politicians
    demanded that it do everything. True though, that NASA said
    'okay'.

>For a long time it even did replace expendables. That was because the
>satellite makers found a bunch of suckers willing to fork over the
>subsidies.

    As do Ariane customers today, and granddaddy of them all looks
    like the Russians selling Proton launches. Cut rate, cheap.

>BTW, another accomplishment of Shuttle was to turn over 60% of the free
>world launch market to Airiane. Funny how Shuttle supporters never
>mention that one.

    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. instead of going to France.
    Then when DC was ready (earlier than currently projected, thanks to
    no wasted efforts on Atlas II, Titan IV et al.) we would still have
    a working relationship with those customers to sell them DC.

    In any case, if General Dynamics resurrected Atlas, Martin resurrected
    the MOL solids for Titan IV, and MD upgraded Delta, what was to stop
    them from developing a brand new system? Why wasn't DC-X built in 1983
    instead of 1993? It was clear back then that Shuttle was neither
    cheaper nor more reliable than the expendables. Afterall, isn't it
    your argument that the next generation of boosters be a commerical
    endeavor? What is it they say about building a better mousetrap?

    -Brian

-------------------------------------------------------------------------
Brian S. Thorn                                    "If ignorance is bliss,
[e-mail]                               this must be heaven."
                                                -Diane Chambers, "Cheers"
-------------------------------------------------------------------------

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End of Space Digest Volume 15 : Issue 611
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