Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V13_6/V13_651.TXT

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Subject: SPACE Digest V13 #651

SPACE Digest                                     Volume 13 : Issue 651

Today's Topics:
               Re: satellite refuelling
              Re: Good for the Japanese
              Re: 3D views from 2d data
              Re: Privatization
             Re: Babies in Space
              NASA and Criticism
              Re: Good for the Japanese
          Re: RE: USF, Inc. : Brought to you by the
               Re: Calculating delta-V
         Re: Self-sustaining infrastructures
            Re: NASA and Criticism
               Re: satellite refuelling

Administrivia:

    Submissions to the SPACE Digest/sci.space should be mailed to
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             [e-mail]

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

Date: 30 May 91 14:54:38 GMT
From: sequent!muncher.sequent.com![e-mail]
Subject: Re: satellite refuelling

In article <[e-mail]> [e-mail] (Henry Spencer) writes:

>...
>One has to weigh the cost of a
>refuelling mission against the cost of a larger launcher and larger
>satellite; it is not at all clear that the balance is always against
>refuelling.

You missed another option, which is to decrease the payload mass in
order to allow more stationkeeping fuel for the same launcher.
When we are talking $billions in satellite redesign and infrastructure to
develop refueling, it is pretty clear that using larger launchers or
decreasing payload mass when extra lifetime is needed is preferable
to adding the mass and complexity of refuelable tanks, and performing
refueling operations them.

For most satellites, the cost of a refueling mission will not be
significantly smaller than the cost of launching a new generation, more
capable satellite.


--
Nick Szabo                [e-mail]
"If you understand something the first time you see it, you probably
knew it already.  The more bewildered you are, the more successful
the mission was." -- Ed Stone, Voyager space explorer

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

Date: 30 May 91 17:21:20 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!swrinde!elroy.jpl.nasa.gov!jato![e-mail]  (Van Snyder)
Subject: Re: Good for the Japanese

In article <[e-mail]> [e-mail] writes:
>In article <[e-mail]>, [e-mail] writes...
>
>>BTW, where were all the astronaut supporters screaming about
>>"international agreements" when Solar-Polar got cut to feed the overgrown
>>Shuttle budget?  What a bunch of hypocrites.
>
>Solar-Polar.  What was once known as the International Solar-Polar Mission
>(ISPM), and is now known as Ulysses, was not cut.  I figured you woulda
>known that, though.  Ulysses had to find a new ride to space after the
>demise of the Shuttle/Centaur program.  Which was based here at Lewis.  And
>which was killed because of the concerns *of the astronauts* in the wake of
>the Challenger tragedy.  So the astronaut supporters were right there.  And
>Ulysses never died, just got delayed.
>
>RG
>
>One hypocrite who knows the skinny.

Only half the skinny.  ISPM was to be a TWO spacecraft mission.  When it
got cut in half, ESA was pissed.

--
[e-mail]
ames!elroy!jato!vsnyder
[e-mail]

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

Date: 30 May 91 18:45:30 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!sdd.hp.com!news.cs.indiana.edu!ariel.unm.edu!nmsu!charon![e-mail]  (Bill Webber)
Subject: Re: 3D views from 2d data

In article <[e-mail]> [e-mail] (Blake Freeburg) writes:
>I am interested in builing a 3D model of the starship enterprise out of
>Star Trek: The Next Generation.  I have good sequences of the ship passing
>overhead, several side views, and it moving away, looking at the back of the
>ship.  I figure there is enough information in these to calculate 1/2 the
>model, and since it is symmetric, I could then build the other half.
>
>Thanks to anyone who can help
>Blake Freeburg

    I believe that very excellent models exist at any nearby hobby
store.  You would save many hours and much $$$$ by basing your model on one
of these, IMHO.

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

Date: 30 May 91 19:28:36 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!usc!hela![e-mail]  (Allen W. Sherzer)
Subject: Re: Privatization

In article <[e-mail]> [e-mail] writes:

>The answers will amaze your typical accountant.  They sure amazed the
>GAO, who raised NASA's Fred estimate by nearly a factor of 4.

Although you point about the difficulty in tracking cost in government
projects is well taken you made a mistake here. The GAO study is an
estimate of the life cycle cost for Freedom. The NASA estimate is only
design and construction costs. You should also bear in mind that the
life cycle costs could be cut by a factor of two to four with suitable
policy changes even after the station is built.

  Allen
--
+---------------------------------------------------------------------------+
|Allen W. Sherzer |   DETROIT: Where the weak are killed and eaten.         |
|   [e-mail]   |                                                         |
+---------------------------------------------------------------------------+

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

Date: 30 May 91 16:14:01 GMT
From: mcsun!ukc!strath-cs!prlhp1![e-mail]  (hodsonb)
Subject: Re: Babies in Space


Are you sure that a foetus in amniotic fluid is the same ?
Whilst the foetus is floating it is still subject to gravity.
For example a hollow spere full of air floating in a liquid
ie displacing its own mass  as an example. In a gravitational
field a ball bearing will fall to the bottom of the spere,
in space or zero gravity conditions the ball bearing will
float.

Therefore there is a distinct difference between a foetus in
space and a foetus subject to gravity but floating. Once the
foetus is born the situation obviously becomes even
more dissimilar.

Ben Hodson. ([e-mail])

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

Date: 30 May 91 19:04:28 GMT
From: wri![e-mail]  (Jeff Lanter)
Subject: NASA and Criticism

[e-mail] (Peter da Silva) writes:

>Who cares about Mars missions? Not I. That's the problem with the space
>station... and all sorts of other NASA stuff: they have *no* idea what
>they want to do. In fact, they don't even have the saving grace of having
>a bad goal: they have no goals at all.

That's a good point.  However, I would have to imagine it's difficult for the
planners at NASA to set big (or "good") goals for themselves, when their
finantial backing can change like the shifting winds.  The space station was,
as it was initially envisioned, to be much larger and capable of a great deal
more than current plans for Station Freedom.  The establishment of larger
short term goals is made impossible by the refusal of government to commit
the $$$ to support a robust space program.

My highly critical, earlier posting was in no way indended as an attack
against NASA.  They have always managed to achieve goals nothing short of
miraculous with what money they had (Viking, Pinoeer, Voyager, Gallileo,
SkyLab, the shuttle program).  My beef lies much higher up in the government.
When President Kennedy set a goal for NASA, he followed up by helping to
insure the necessary funding was available.  Despite what goals Reagan might
have claimed to set for NASA, his followup in the funding department was
less than adequate.  Bush is proving to be even worse.

I will always look to NASA to be the world leader in space technology and
space exploration.  I will also be looking with a very critical--if not
downright cynical--eye to the members of congress to uphold the tradition of
expansion and exploration.  Of course, others will argue that federal moneys
should be more appropriately be spent on social programs and problems here on
Mother Earth.  I can't argue that there is cause to answer those needs.
However it is done, I certainly hope that congress will quit keeping such a
choke hold on our space program.  How did the President's words go...?

"We choose to go to the moon and to do these other things, not because they
are easy, but because they are hard.  Because they will serve to measure the
best among us."

I'm sure I've slaughtered his words, but you get the idea....

-----Jeffrey

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

Date: 30 May 91 20:21:06 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!wuarchive!rex!rouge!pc.usl.edu![e-mail]  (Phil)
Subject: Re: Good for the Japanese


Will writes:

\In just few QUARTERS we started a project, partly worked on it and
/restarted it again.  The International community does'nt really
\work this way.  Japan thinks in terms of 50 years, Europe too,
/about 50 years.  America thinks in terms of now.  This very minute.

Actually, that's the way America's _Public Sector_ works. In spite
of all the hubub going around about how government thinks in longer
terms than private enterprise, the truth is government is divided
between those who think in terms of (suprise!) two year terms (of
office), one guy thinking four year terms, and about a hundred or
so who think in six year terms.

Private enterprise is thinking as long term as it can afford to,
given what the government has done to all the investment capital
with its massive debt (and also the Investment Discouragement, oops,
Capital Gains Tax).

Cooperation between Japan and America will probably decreace a
lot after the cancellation, or even if Fred survives, at least
in the group "Japanese Government/American Government." Japanese
and Americans may continue to cooperate.

I suspect in the future that international cooperation will be
more "person to person" than "government to government."

Phil Fraering || Usenet (?):[e-mail] || YellNet: 318/365-5418
Standard disclaimer, whatever a disclaimer is, applies.
''It hardly mattered now; it was, in fact, a fine and enviable
madness, this delusion that all questions have answers, and nothing is
beyond the reach of a strong left arm.`` - Larry Niven and Jerry
Pournelle, _The Mote in God's Eye_

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

Date: 31 May 91 05:14:16 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!usc!ucselx!petunia!zeus![e-mail]  (James T. Green)
Subject: Re: RE: USF, Inc. : Brought to you by the

I would be interested in seeing a listing of the major
members (not honorary types, such as the UN sec. general
seems to be).  I admit that I've not read throughly all
the loooooong postings about this organization and such info
might be there, but I think a posting of only the major
movers and their credentials is in order.

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*  "I believe that this nation should commit itself to achieving  *
* the goal, before this decade is out, of landing a man on the    *
* Moon and returning him safely to the Earth."                    *
*                  <John F. Kennedy; May 25, 1961>                *
* =============================================================== *
*                   (-:   James T. Green   :-)                    *
*              Internet: [e-mail]                  *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

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

Date: 30 May 91 01:44:08 GMT
From: csus.edu!wuarchive!zaphod.mps.ohio-state.edu!usc!chaph.usc.edu!sal-sun10.usc.edu![e-mail]  (The Black Sheep)
Subject: Re: Calculating delta-V

In article <[e-mail]> [e-mail] (Matthew DeLuca) writes:
>In article <[e-mail]> [e-mail] (Loren Petrich) writes:
>
>>    In "English" units, there is a unit of mass called the "pound"
>>and a unit of force called a "pound". Their ratio is the acceleration
>>of gravity, about 9.8 m/s^2. In this type of system, the ratio of
>>force to mass rate is measured in seconds, when it is really a
>>velocity, the effective exhaust velocity (EEV).
>
>Actually, the unit of mass in the English system is the slug.

Oh? When was the last time you bought a 2-slug steak? :-)

>At one g, the weight of this unit is 32.2 pounds.

And, of course, the acceleration of gravity is 32.2 ft/sec^2...



            But let us move on...


--
===============================================================================
Ron A Echeverri,        |  "God is a necessary invention. If there is
The Black Sheep            |    no god, we would have to invent Him."
BSAE 1994 Univ of So California |            - Voltaire

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

Date: 31 May 91 23:54:12 GMT
From: usc!zaphod.mps.ohio-state.edu!think.com!mintaka!ogicse!sequent!muncher.sequent.com![e-mail]
Subject: Re: Self-sustaining infrastructures

In article <[e-mail]> [e-mail] (Frank Crary) writes:

>For a 2-man station, of a soviet Mir-type, able to maintain/refuel/repair
>50 satellites / year, the OMV to move the satellites around, and the logistical
>support of this system...
>
>approximately $ 5,000 Million to develop/launch
>        1,500 Million per year to support


>This comes to $30 million per satellite repaired.


This is stupendously wrong.

* The best cost estimate for a four-man station is $120,000 million
  (GAO). It is unknown what Mir costs.  A two man station requires the same
  life support, refuelling, etc. equipment R&D and would not, I think,
  cost significantly less than a 4-man job.

* You don't show how either your development or operational cost
  figures are derived.

* The number of satellites launched into any particular low earth orbit
  reachable by an OMV is less than 5/year, not 50/year.  The number of
  those actually benefiting from refueling is probably no more than one per
  year; other satellites can be redesigned for optimum component/fuel
  lifetime balance for less than $30 million.

* You didn't even bother to amortize the $5 billion.


Over 30 years at 10%/year, this comes to $7,800 million per repair,
about 6 times the cost of launching a brand new Hubble telescope,
and 160 times the cost of making the largest launcher upgrade
that could conceivably be needed (Titan 3 to Titan IV, c. $50 million)
to add fuel to a large commercial satellite.

To put it another way, we could launch 4 entire fleets of 77 commercial
phone cell satellites for every one satellite your system could refuel.

Even using the Shuttle ($900 million per launch) is far more economical
than your scheme, although still far away from breakeven, which is
amortization and operation costs of less than $50 million per year for LEO.




--
Nick Szabo                [e-mail]
"If you understand something the first time you see it, you probably
knew it already.  The more bewildered you are, the more successful
the mission was." -- Ed Stone, Voyager space explorer

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

Date: 1 Jun 91 08:49:40 GMT
From: cis.ohio-state.edu!pacific.mps.ohio-state.edu!linac!Firewall!ddsw1![e-mail]  (Sameer Parekh)
Subject: Re: NASA and Criticism

In article <[e-mail]> [e-mail] (Eric Miller) writes:
[Good thoughts deleted]
>Are these really such difficult issues for politicians and their constituents
>to grasp???
>
    Yes.



--
The Ravings of the Insane Maniac Sameer Parekh -- [e-mail]

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

Date: 1 Jun 91 22:20:18 GMT
From: haven.umd.edu!socrates.umd.edu!socrates![e-mail]  (Raul Rockwell)
Subject: Re: satellite refuelling

Allen W. Sherzer:
   Again, it's like the early days of avation and the Kelly Act.
   Without it and the incentives it provided (multi-engines, advanced
   navigation and large cargo areas) we wouldn't have the aerospace
   industry we have today.

Maybe.  Then again, maybe not.  It's kinda hard to second guess the
past, especially when you're talking about the interaction between the
government and private innovation.

Or, if I phrase that differently, without the Kelly act (and other
aviation related legislation and regulation) we might have a more
advanced aerospace industry than what we currently have.  But how
could you verify something like this?

Raul Rockwell

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

End of SPACE Digest V13 #651
*******************