Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT_ZIP/spacedig/V16_0/V16NO090.ZIP/V16NO090

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Date: Fri, 29 Jan 93 05:27:54
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V16 #090
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Space Digest                Fri, 29 Jan 93       Volume 16 : Issue 090

Today's Topics:
                              Beanstalk?
           DC-1 eventual construction question... (2 msgs)
Fluidic envelope on a point gravitational source suspended in a uniform field
                  How many MO's were there planned?
             Making Orbit 93 - The Delta Clipper Program
                     Orbital Mechanics--Careers?
              Rent Mir/Commerical SS Fred not build it.
                    Saving an overweight SSTO....
                  THE DIVINE MASTERS OF THE UNIVERSE
            Today in 1986-Remember the Challenger (2 msgs)

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Date: Thu, 28 Jan 1993 18:19:22 GMT
From: Ed Faught <[e-mail]>
Subject: Beanstalk?
Newsgroups: sci.space

In article <[e-mail]> [e-mail] writes:
>Does anyone know anythng about how to build a beanstalk?
>
Magic beans.

--
Ed Faught  WA9WDM  [e-mail]
 Superconducting Super Collider Laboratory

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

Date: 28 Jan 93 10:39:17 PST
From: [e-mail]
Subject: DC-1 eventual construction question...
Newsgroups: sci.space

In article <[e-mail]>, [e-mail] (Edward V. Wright) writes:
> In <[e-mail]> [e-mail] writes:
>
>>My question is more on the order of "how do we convince the manufacturers that
>>they will be able to sell these things?"  Including the possibility that
>>somehow WE as a group step up, and place an order.
>
> One order is not going to convince Boeing to do anything.  They already
> know they could get one order.  The problem is, one vehicle could fly
> off the *entire* backlog of satellite launch orders, plus soon-to-be
> orders such as Iridium, in short order.  What Boeing wants is to see
> is proof that there's a large enough market to keep the orders coming
> in, and that's not satellites.
>
Well, lets not limit this to Boeing.  I know less about the development cycle
for MD, and the rest of the people mentioned in earlier posts that want to
build SSTO's.

The real question is again "what specifically will it take"...  two separate
companies making orders...  5 separate companies...  1 company ordering 10 ...
1 company ordering 20...

Assuming that the airline operational characteristics can be met (or hell,
even double that cost), and assuming that the tourism paper from that U.K.
guy is right, can you make money and pay off one of these things flying
say, 5 guys a week, at $50k per head, with a satellite launch for 1 or 2 mil
every other flight?  Assume that the satelite market goes away right after
you fly off the backlog (enough to pay off the first one?)  Thats 1/4 mil per
flight, for operational revenues of 12.5 mil per year (2 weeks off for
dedicated maintenance)

Can you put 5 guys up for a week in the payload bay of a proposed SSTO? or
is it more like 10?

Yes, later, you can put up a hotel can, and fly only saturday to take new
ones, and return old ones, and do something else during the week, but not at
first...  (Besides, at this point, you can make the can (like a tinker toy
set) big enough to run two rotations, and then three, and then...  so as the
cost of the flight goes down, you get more economy in scale...)  And then, the
first few flights, would cost more, in order to take advantage of the scarcity
of the product.  You might even get John Denver for 5 mil for your FIRST
customer, and then some others at 1 mil each for the first 10 or 15 flights)
(And, yes, I realize that the developer will probably charge more for the
first one, so you can scratch thinking about making gobs of extra money off
these first flights.)

Assume that production SSTO's will cost what an airliner does, $40 mil or so,
right?  After operational expenses, fuel, etc...  The 12.5 mil/year leads
to payoff of the craft in 5 or so years.  How does an airline amoratize
its craft.  They have lasted 20 years, right?  Can you make enough money to
buy a second and a third, and a fourth...

These figures are so rough it hurts my hands to type them.  What are more
reasonable numbers.  Who puts them together?  And again, what are the potential
developers REALLY looking for in order to get into the SSTO production
business?

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

Date: 28 Jan 1993 14:36:07 -0500
From: Pat <[e-mail]>
Subject: DC-1 eventual construction question...
Newsgroups: sci.space

 John asserts Boeing doe snot study the airplane market on an operational
sense.

I have to disagree.  I know the other big companies constantly study the passeng
er market, looking for missions.  Sure, the airlines study the market,
but Boeing has to figure out what distance, payload and cost and speed.

the 727, 707, 747, 767 were all developed based upon studies that
N number of people wanted to go between certain distances and at certain
times.  otherwise we'd still be using DC-3s.

pat

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

Date: Thu, 28 Jan 1993 19:27:34 GMT
From: Benjamin T Dehner <[e-mail]>
Subject: Fluidic envelope on a point gravitational source suspended in a uniform field
Newsgroups: talk.origins,sci.space

In <[e-mail]> m23364@mwunix (James Meritt) writes:

(Unless noted otherwise, all physical data on the planets is from either
Zelik and Smith "Introductory Astrophysics" (1987) Saunders College,
Philidelphia and Abell, Morrison, and Wolf "Exploration of the Universe"
(1987) Saunder College: Philidelphia)

>What would the characteristics be of the fluidic envelope (atmosphere and
>hydrosphere) of a gravitational point source (say, the earth) if it were to
>be suspended (through some magical method which would NOT affect the oceans)
>in a uniform (or near-uniform) intense (approximately 6 meters per second
>per second) gravitational field (say, from something that would become Saturn)?

    Ok. let's assume our "proto-Saturn" had a mass of about 1.e31 gm.
This is about 20 times it's current mass, and about the minimum it would take
to induce fusion in the saturnian core, and make a star out of saturn.
(For comparison, the mass of the Sun is about 2.e33 gm; this is a damn small
star we're talking about).
    In order to have 1 6m/s/s gravitional field, this would require that
the earth be at a distance of about 3.3e10 cm.  For comparison,
1 A.U. = 1.5e13, Saturn's closest (known) moon Atlas is at 1.4e10 cm, and
a middin' moon Dione is at 3.8e10 cm.)  So earth is a hell of a lot closer
to proto-Saturn than it is now to the current sun.
    Now, how big is this P-Saturn?  If we choose to keep Saturn at the
same density, we must increase the radius by a factor of 20**(1/3),or about
2.7.  This would give us an equatorial radius of 1.55e10 cm, which is about
one/half the earth's projected orbital radius.  Off the top of my head, I'm
not sure whether the Saturnian density should go up (do too increased
gravitational fields) or down (fusion ==> hot gas, expands.)
    Lets examine one possible problem by calculating the Roche Limit.
This is given in Zelik and Smith (derived from conisdering the self-gravity
of the earth compared to the gradient of the Saturn gravitaional field)
to be about (assuming a rigid body)
             d = Rearr*(3*Msat/Mear)**(1/3)
so the above guestimates give us d = 1.1e10.  (If we use the original Roche
formula for fluid, instead of rigid body, we get about 1.9e10.  So it does
apear that earth will be outside of the Roche limit.  However, even though
outside the Roche limit, there is still one hell of a gradient force which
cannot be neglected.
    Finally, let's put the photospheric temperature of this star at about
2000K, which is about as cool a star as you can get.  (Sun is at 5800K).
(Keep in mind that this will make this a very red star.)
This gives us an energy flux at the earths radius of
                0.9*0.5*4*pi*rsat**2/dise**2*sigma*T**4
where pi = 3.14 (you know this one)
      rsat = radius of saturn
    ( ==>  4*pi*rsat**2 = surface area of Saturn)
      dise = distance of earth from Saturn
      0.5 = from fact only see 1/2 of star
      0.9 = fudge factor for limb darkening
      sigma = stefan-boltzman constant, 5.67e-5 erg/cm**2/K**4/s
and so our 'Saturnian constant' would be
    Ssat = 1.06e9 erg/cm**2/s

compare this to today's solar consant of 1.37e6 erg/cm**2/s, and it seems that
earth is a rather warm place. -- about 1000 times the amount of energy input
from Saturn.  More on this in a bit.

>Off hand, I wonder about the long-term status of the atmosphere.  Would the
>escape velocity on the "near" side be reduced such that the molecular velocity
>at "room temperature" be sufficient to "bleed off" the air?  What WOULD the
>imposition of a uniform field over the inverse square field do the e.v.?
>Someone care to perform the integral?

    Ok, now what about the atmosphere? The force away from the earth
on a molecule in the atmosphere will be given by
    F(r) = G*m*(Mearth/r**2 - Msat*cos(b)/diss**2)
where
    Mearth = mass earth
        Msat = mass saturn
        r = distance of object from earth center
        diss = distance of object from saturn
        diss**2 = dise**2 + r**2 - 2*dise*r*cos(b) [law of cosines]
        b = angle bewteen object and Saturn as seen from Earth.

    A molecule will be lost to space when it's velocity is high enough
so that, when it reaches an infinite distance from earth, (where gravity from
earth is now 0) it is still moving (can't be pulled back).  Or, as a limiting
case, when the velocity at infinity is zero.  Or, when the work done on the
particle (\int F dx) does not equal it's kinetic energy.  So if we start at
velocity V at the earth surface, the escape velocity will be

             /infinity
            |
Vesc**2 = 2G| [-Msat*cos(b)/(r**2+dise**2 - 2*cos(b)*r*dise) + Mear/r**2] dr
            |
           /Rearth

which evalutates too (not a hard integral; split into two components, and
use algebraic substitution)(and change notation d = dise)

Vesc**2 = Vold**2 - 2*G*Msat*cos(b)(pi/2 - arctan(Rear**2+d**2*(1-cos(b)**2))

Where Vold is the nominal value of the escape velocity of 1.12e6 cm/s.
Expanding the arctan in a series, this gives us

Vesc**2 = Vold**2 - 2*G*Msat*cos(b)/(Rear**2+d**2*(1-cos(b)**2))

Taking as a representive value of cos(b) = 1/2, for a numeric example we have
Vesc = 1.119e6 cm/s.  So in this case, the change in the escape itself
is rather small.  I would suspect that a more major loss of atmosphere
would be caused by the extreme irradiation at the top layers from being so
close to the Saturnian photoshpere.

    Getting back to this, what of the 1000-fold increase in the energy
flux at the top of the earth's atmosphere?  Let's assume an albedo of 0.8
(Venus is 0.76) which, among other things, implies thick cloud layers such
that no one would ever SEE the bloody sun.  If we let energy freely radiate
at the opposite side of the earth (to 0 K space) the equlibrium temperature
will be such that Flux(in) = Flux(out), or

2*pi*Rear**2*.2*1.e9 = 4*pi*Rear**2*sigma*T**4

T**4 = .2*1.e9/(2*sigma)

T = 1152 K

    While this is an incredibly crude approximation, the point is made
(I think) that the earth will be fried.

>--
>James W. Meritt:  [e-mail] - or - [e-mail]
>The opinions above are mine.  If anyone else wants to share them, fine.
>They may say so if they wish. The facts "belong" to noone and simply are.
--
-----------------------------------------------------------------------------
Benjamin T. Dehner    Dept. of Physics and Astronomy
[e-mail]       Iowa State University
                      Ames, IA 50011

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

Date: 28 Jan 1993 14:19:08 -0500
From: Pat <[e-mail]>
Subject: How many MO's were there planned?
Newsgroups: sci.space

I know the current MO was technically the Geochemistry/climatology
bird.(If memory serves)   How many other birds were planned at what would there missions be?

pat

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

Date: 28 Jan 93 19:27:07 GMT
From: Pat <[e-mail]>
Subject: Making Orbit 93 - The Delta Clipper Program
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (Larry Wall) writes:
>In article <[e-mail]> [e-mail] (Bruce Dunn) writes:
>: vehicle is rotated base down.
>
>How do they guarantee they don't get upside-down-spraycan syndrome?
>


[ Stuff Deleted about empty SPray Cans}


I imagine the problem can be solved by looking into the inventory of Aircraft appli
applications under fuel tanks.  I know for many smaller aircraft,  this problem
is avoided by having the fuel feeders be on flex hose, with a little
pendular mass.   normally, they hang about 1" off the tank bottom, but during
severe manuevers they roll with the fluid body.
now granted this may be a little tougher with cryogenics, but i am sure
some sort of engineered flex could be bobbed in there.

pat

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

Date: Thu, 28 Jan 1993 16:43:48 GMT
From: fred j mccall 575-3539 <[e-mail]>
Subject: Orbital Mechanics--Careers?
Newsgroups: sci.aeronautics,sci.research.careers,sci.space,soc.college.grad

In <[e-mail]> [e-mail] (Srinivas Bettadpur) writes:

>    * I know of UT-Austin, MIT, Stanford, UC-Boulder, VPISU, U. Mich-Ann
>Arbor, U. Ill.-UC, Purdue, Auburn U. as offering any significant
>graduate programs in CM in the US.

Uh, that's CU-Boulder.  Yes, I know the school is called University of
Colorado, but we still abbreviate it CU.

[No, I know nothing about their curriculum wrt. CM; I just happened to
go to school there for something else.]

--
"Insisting on perfect safety is for people who don't have the balls to live
 in the real world."   -- Mary Shafer, NASA Ames Dryden
------------------------------------------------------------------------------
[e-mail] - I don't speak for others and they don't speak for me.

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

Date: 28 Jan 1993 14:11:32 -0500
From: Matthew DeLuca <[e-mail]>
Subject: Rent Mir/Commerical SS Fred not build it.
Newsgroups: sci.space

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

>The Russians alreay have Mir up in space, why not used it to build a
>American/US space station, or build a wing onto Mirt that is for US use..
>I know Mir is far from ideal, but what is.. Why reinvent the wheel when the
>wheel is already in Orbit??

Because if you just keep using the same wheel, you never develop better
wheels.  Sure, we can do as some people have suggested and rent Mir and
buy Soyuzes and use Energia and save lots of money, but the end result would
be the complete stasis of the space arm of the U.S. aerospace industry,
coupled with Russian dominance of space down the line.

The short of the matter is that if all you are concerned with is the
almighty dollar, what you suggest is a good idea.  If you are interested
in a strong U.S. space program, however, it's a losing deal.
--
Matthew DeLuca
Georgia Institute of Technology, Atlanta Georgia, 30332
uucp:      ...!{decvax,hplabs,ncar,purdue,rutgers}!gatech!prism!matthew
Internet: [e-mail]

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

Date: Thu, 28 Jan 1993 17:13:10 GMT
From: "Edward V. Wright" <[e-mail]>
Subject: Saving an overweight SSTO....
Newsgroups: sci.space

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In <[e-mail]> [e-mail] (fred j mccall 575-3539) writes:

>True, but what's to stop them from simply stuffing some cargos in
>AIRPLANES and taking them to a pickup point?  After all, flying a C-5
>to Ecuador would have to be cheaper than flying a spaceship back from
>Ecuador to pick up a load.

The US Customs and State Department, to begin with, if you're
talking about satellites and other high-tech payloads.

However, the marketing studies say that satellites are only
a small part of the market.  The major markets are overnight
or same-day letter/package delivery, intercontinental passenger
flights (less than one hour to any point in the world, no time
for an inflight movie), and space tourism.

Space tourists might accept Ecuador as a jump-off point -- many
cruises depart from out-of-the-way points today -- but it will
reduce the size of your market.  But Federal Express and Northwest
Airlines passengers won't.  They want to go directly from San Francisco
to Tokyo.

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

Date: 28 Jan 1993 19:35:14 GMT
From: David Gutierrez <[e-mail]>
Subject: THE DIVINE MASTERS OF THE UNIVERSE
Newsgroups: sci.space

In article <[e-mail]>
[e-mail] (James L Olive) writes:
>>     (3) It is possible for INDIVIDUALS to PERSONALLY explore the Universe,
>>including our Solar System, using forms of "SOUL TRAVEL".

Or for longer trips, "SOUL TRAIN"?

David Gutierrez
[e-mail]

"Only fools are positive." - Moe Howard

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

Date: Thu, 28 Jan 1993 18:37:47 GMT
From: "Keith A. Grimm" <[e-mail]>
Subject: Today in 1986-Remember the Challenger
Newsgroups: sci.space,sci.space.shuttle

In article <5=[e-mail]>, [e-mail] (Sean Michael Gallagher) writes:
|> [e-mail] (Simon E. Booth) writes:
|>
|>
|> >Just a reminder- 7 years ago today- 11:38am EST....
|> >So, where were you when the Challenger disaster took place?
|> >It was during my sophomore of high school, and I was in English class
|> >when they told us.
|> >No tribute of any sort was allowed, nor could we openly talk about it
|> >without some sort of negative reaction from administrators.
|> >I remember it well, I even got in 'trouble' for this.
|> >Pro-space exploration views were not welcome.
|> >At least now things have improved.
|> >Simon
|
I was watching the launch in the conference room here at JSC.  I had worked for
 NASA for 6 months.  51-L was the first flight I worked with in one of the
 simulators here.  I knew some of the crew.  They were wonderful people.


Keith A. Grimm
NASA-JSC
Houston, TX  77058

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

Date: 28 Jan 1993 11:34 PST
From: "Horowitz, Irwin Kenneth" <[e-mail]>
Subject: Today in 1986-Remember the Challenger
Newsgroups: sci.space

I too, remember quite clearly where I was and what I was doing on 28 Jan 86.
It was my senior year at MIT and I had just finished a three week program at
Lowell Observatory and was visiting my parents in South Florida.  I got up that
morning watching the TV for news on the shuttle launch.  When I heard about the
delays and the pad condition, I figured that there was no way they would launch
that day, so I decided to pop a video of "Close Encounters" into the VCR.  When
the movie finished, the TV came back onto CNN, where I saw a graphic of the
Shuttle disaster.  I ended up spending the rest of the day in a state of shock.

To this day, I still can not watch "Close Encounters" b/c of this association.
-------------------------------------------------------------------------------
Irwin Horowitz                        |
Astronomy Department                  |"Whoever heard of a female astronomer?"
California Institute of Technology    |--Charlene Sinclair, "Dinosaurs"
[e-mail]                |
[e-mail]                 |
-------------------------------------------------------------------------------

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End of Space Digest Volume 16 : Issue 090
------------------------------