Space & Astronomy/Space and Astronomy (October 1993).iso/pc/text/spacedig/v08/v8_291.txt

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Date: Sat, 23 Jul 88 19:06:28 PDT
From: Ted Anderson <[e-mail]>
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Subject: SPACE Digest V8 #291

SPACE Digest                                      Volume 8 : Issue 291

Today's Topics:
            Space station elements
              Re: Rocket engine
               Re: Mir and solar flares
            Re: Re: Rocket engine
               Re: Space Cities
             Re: Ramscoop engine
               Re: Space Cities
     Soviet launch 1st Phobos mission & Spacewalk update
               RE: SPACE Digest V8 #261
       Re: Comment about science was Re: Rocket engine
----------------------------------------------------------------------

Date: 18 Jul 88 18:25:00 GMT
From: a.cs.uiuc.edu!m.cs.uiuc.edu![e-mail]
Subject: Space station elements


Two-line elements for Salyut 7
1 13138U          88195.72059195 0.00003607           12264-3 0  1563
2 13138  51.6097 161.5347 0000460 189.9869 170.1893 15.33053410356157

Object: Salyut 7
NORAD catalog number: 13138
Element set: 156
Epoch revolution: 35615
Epoch time: 88195.72059195 (Wed Jul 13 17:17:39 UTC)
Inclination: 51.6097 degrees
RA of node: 161.5347 degrees
Eccentricity: 0.0000460
Argument of periapsis: 189.9869 degrees
Mean anomaly: 170.1893 degrees
Mean motion: 15.33053410 revs / day
Mean motion acceleration: 0.00003607 * 2 revs / day**2
B* drag term: 1.2264e-04

Derived figures:
Semimajor axis: 6844.55 km.
Perifocal radius: 6844.23 km.
Apogee height: 466.72 km.
Perigee height: 466.09 km.
Mean longitude at the epoch: 2.8224 degrees.
Magnitudes of short-period perturbations of the second harmonic:
    Radius vector magnitude: +/-0.99 km.
    True anomaly: +/-0.0114 degrees.
    RA of node: +/-0.0251 degrees.
    Inclination: +/-0.0197 degrees.
Secular perturbations of the second harmonic:
    Argument of perigee: 3.6123 degrees/day
    RA of node: -4.8331 degrees/day
    Mean anomaly: included in published mean motion.
Long-period perturbation of the third harmonic: X=-1.613e-03, Y=-8.564e-04

Two-line elements for Mir
1 16609U          88195.75450030 0.00029876           20257-3 0  3069
2 16609  51.6163 290.8517 0002993 137.6327 222.4454 15.74713290138015

Object: Mir
NORAD catalog number: 16609
Element set: 306
Epoch revolution: 13801
Epoch time: 88195.75450030 (Wed Jul 13 18:06:28 UTC)
Inclination: 51.6163 degrees
RA of node: 290.8517 degrees
Eccentricity: 0.0002993
Argument of periapsis: 137.6327 degrees
Mean anomaly: 222.4454 degrees
Mean motion: 15.74713290 revs / day
Mean motion acceleration: 0.00029876 * 2 revs / day**2
B* drag term: 2.0257e-04

Derived figures:
Semimajor axis: 6723.29 km.
Perifocal radius: 6721.27 km.
Apogee height: 347.153 km.
Perigee height: 343.128 km.
Mean longitude at the epoch: 5.0777 degrees.
Magnitudes of short-period perturbations of the second harmonic:
    Radius vector magnitude: +/-1.01 km.
    True anomaly: +/-0.0119 degrees.
    RA of node: +/-0.0260 degrees.
    Inclination: +/-0.0204 degrees.
Secular perturbations of the second harmonic:
    Argument of perigee: 3.8432 degrees/day
    RA of node: -5.1444 degrees/day
    Mean anomaly: included in published mean motion.
Long-period perturbation of the third harmonic: X=-1.642e-03, Y=-8.719e-04


Source: NASA Goddard via TS Kelso's `Celestial RCP/M'

NOTE: Apogee and perigee heights are referred to a mean equatorial radius
      of 6378.145 km, and not to the local radius of the geoid.
      All derived quantities are calculated using the NORAD SGP model of
      Hilton and Kuhlman.

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

Date: 7 Jul 88 23:48:39 GMT
From: thumper![e-mail]  (Phil R. Karn)
Subject: Re: Rocket engine

> Los Alamos simulates nuclear explosions using their Crays; I suspect that
> the pressures and speeds are somewhat larger than in rocket engines.

Good point. But I would say that rockets are a bit more controlled, and
require tighter performance tolerances, than your average thermonuclear
device. The components also have to operate a bit longer...

It's probably safe to say that bomb design, like rocket design, is more
art than science. Otherwise the comprehensive test-ban treaty wouldn't
be such a big issue. The whole point of a test ban is to inhibit the
development of new weapons. If computer simulation were all that is
needed, I'd think we'd find the hawks on the American side strongly
supporting a ban because of our considerable computational advantage
over the Soviets. But it's the hawks on our side that oppose it most
vigorously.

Phil

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

Date: 6 Jul 88 13:50:44 GMT
From: mcvax!ukc!etive![e-mail]  (B Gray)
Subject: Re: Mir and solar flares

In article <[e-mail]> [e-mail] (Glenn Chapman) writes:
>    Speaking of the EVA, Titov and Manarov on board Mir went out this morning
>(June 30th) for 5 hours to try and fix the British/Dutch X-ray telescope on the
>Kvant module.  The current information I have is either the repair did not work,
>or was not finished.  They plan another EVA in a few days.

Their screwdriver broke when they were trying to lever off a
fixing ring. The tip of the screwdriver was left stuck behind
the ring. The telescope was never designed to be worked on
in orbit by people in spacesuits.

They are to decide whether it will be possible to fix the
problem on a later EVA.
    Bob.

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

Date: 7 Jul 88 21:23:27 GMT
From: hpda!hpcuhb!hpsel1![e-mail]  (Bob Campbell)
Subject: Re: Re: Rocket engine

> Los Alamos simulates nuclear explosions using their Crays; I suspect that
> the pressures and speeds are somewhat larger than in rocket engines.
----------

But then a nuclear device does not have to maintain an equilibrium state.
It also has fewer parts.  I would have expand that both rocket engines and
motors are not as understood as the general public might think.


Bob Campbell                Some times I wish that I could stop you from
[e-mail]        talking, when I hear the silly things you say.
Hewlett Packard                                    - Elvis Costello

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

Date: Fri,  8 Jul 88 06:03:15 EDT
From: "Keith F. Lynch" <[e-mail]>
Subject: Re: Space Cities
To: uflorida!novavax![e-mail]
Cc: [e-mail], [e-mail], [e-mail]

> From: uflorida!novavax![e-mail]  (Thomas Maddox)

> So far as I know, the accepted general designs fall into
> rotating torus, sphere, or cylinder, all providing spin-induced
> forces approximating gravity.

People might come to prefer weightlessness.

> I am currently using the "Stanford torus" model, as outlined
> in T. A. Heppenheimer's _Colonies in Space_.  (Slightly over a
> mile in diameter, with a 1 rpm spin rate, central hub 400 feet
> in diameter, six spokes 50 feet wide going to an outer rim.)

Too fast!  That will give you about 3 Gs.

> the city will occupy a "2:1 resonant orbit" that is 200,000 miles
> from Earth at farthest point, 100,000 miles at closest.

You'd better have good radiation shielding.

> What vistas can you see opening up in a space city, what unique
> possibilities that one cannot expect life on Earth to provide?

Freedom from earth governments.  Immunity to earth's diseases (if
colonists and imports are tested for them).  Much higher population
than earth (if you have enough space cities) which allows vast
economies of scale, vast diversity of cultures and mores, and a
"Newton" or a "Mozart" born every day instead of every few centuries.
Physical decentralization, providing immunity from disease, war, and
ecological collapse (whether natural or manmade).  Self-contained
environments suitable for eventual multi-generation travel to the
stars (why leave home if you can take it with you?) leading to
eventual colonization of the galaxy and the universe and/or contact
with aliens if there are any, and leading to probable survival of
mankind or our descendants until the end of time (if any).

> I want to have my city dwellers snag a metal-rich asteroid.
> I'm almost totally unclear on a few essentials.  How big can it
> reasonably be?  (I want it to have enough size to sustain tunnels
> in which a few a characters are going to have Amazing Adventures;
> I want it to be transportable.)

Why not have the people go to the asteroids, instead of vice versa?
Have your adventures in the asteroid belt.  Still plenty of light,
much more available mass, much less dangerous radiation, and much
easier to hide from enemies.  100k miles from earth is a little too
close - you might get raided by earth governments or targeted in
earth's wars.  And who can blame earth governments for getting nervous
when a huge asteroid is aimed almost straight at earth?  A big impact
could really rearrange the continents a bit.

> my sf is new school (no Heinleinian digressions on the nature of the
> good life, high-tech (in the cyberpunk mode, I reckon), ...

I hope it isn't ultra-cynical and gutter-bound like Gibson's.  I prefer
optimism and light, as in Heinlein, Busby, Bear, Hogan, Varley, and
Vernor Vinge.
                                ...Keith

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

Date: 7 Jul 88 11:41:35 GMT
From: b.gp.cs.cmu.edu![e-mail]
Subject: Re: Ramscoop engine

In article <[e-mail]>, [e-mail] writes:
}One more question I can think of off the top of my head -- what happens
}to heat dissipation as time slows down?  As the fusion reactor approaches
}light-speed, would its heat dissipation also slow down, thus causing
}a meltdown?

No, it wouldn't melt down because the heat generation would also be slowed
down.  From the frame of reference of the reactor, neither the fusion nor heat
dissipation have slowed down, since they are moving together with the reactor.

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

Date: Fri,  8 Jul 88 06:06:06 EDT
From: "Keith F. Lynch" <[e-mail]>
Subject: Re: Space Cities
To: uflorida!novavax![e-mail]
Cc: [e-mail], [e-mail], [e-mail]

> From: uflorida!novavax![e-mail]  (Thomas Maddox)

> So far as I know, the accepted general designs fall into
> rotating torus, sphere, or cylinder, all providing spin-induced
> forces approximating gravity.

People might come to prefer weightlessness.

> the city will occupy a "2:1 resonant orbit" that is 200,000 miles
> from Earth at farthest point, 100,000 miles at closest.

You'd better have good radiation shielding.

> What vistas can you see opening up in a space city, what unique
> possibilities that one cannot expect life on Earth to provide?

Freedom from earth governments.  Immunity to earth's diseases (if
colonists and imports are tested for them).  Much higher population
than earth (if you have enough space cities) which allows vast
economies of scale, vast diversity of cultures and mores, and a
"Newton" or a "Mozart" born every day instead of every few centuries.
Physical decentralization, providing immunity from disease, war, and
ecological collapse (whether natural or manmade).  Self-contained
environments suitable for eventual multi-generation travel to the
stars (why leave home if you can take it with you?) leading to
eventual colonization of the galaxy and the universe and/or contact
with aliens if there are any, and leading to probable survival of
mankind or our descendants until the end of time (if any).

> I want to have my city dwellers snag a metal-rich asteroid.
> I'm almost totally unclear on a few essentials.  How big can it
> reasonably be?  (I want it to have enough size to sustain tunnels
> in which a few a characters are going to have Amazing Adventures;
> I want it to be transportable.)

Why not have the people go to the asteroids, instead of vice versa?
Have your adventures in the asteroid belt.  Still plenty of light,
much more available mass, much less dangerous radiation, and much
easier to hide from enemies.  100k miles from earth is a little too
close - you might get raided by earth governments or targeted in
earth's wars.  And who can blame earth governments for getting nervous
when a huge asteroid is aimed almost straight at earth?  A big impact
could really rearrange the continents a bit.

> my sf is new school (no Heinleinian digressions on the nature of the
> good life, high-tech (in the cyberpunk mode, I reckon), ...

I hope it isn't ultra-cynical and gutter-bound like Gibson's.  I prefer
optimism and light, as in Heinlein, Busby, Bear, Hogan, Varley, and
Vernor Vinge.
                                ...Keith

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

Date: Fri, 8 Jul 88 15:28:16 EDT
From: Glenn Chapman <[e-mail]>
Subject: Soviet launch 1st Phobos mission & Spacewalk update

     The Soviet Union successfully launched the first of the Phobos/Mars
probes from the Baikonur cosmodrome today (July 7th).  The exact launch
time was not given but the it was listed on the 5:00 pm EDT news of
Radio Moscow.  The launch was shown live on Soviet TV and taped versions
were seen on several of the nightly news broadcasts here.  All that is said
so far is that the orbital insertion was correct.  There is no statement of
when the on orbit burn to shape the interplanetary orbit to Mars will occur
(probably sometime July 8th).  These pictures of the Proton launch vehicle
were excellent even if it was a night launch (they retained a spot light
on the vehicle for a considerable distance).
     There have been several excellent descriptions of this probe recently,
and I am working on a summary of those for posting in a few days.  For
those that are interested I suggest you get the current issues of Sky and
Telescope, plus Spaceflight (the British Interplanetary Society magazine),
and the March 3rd issue of New Scientist.
     The Russians were holding a news conference just prior to this launch
where they laid out more plans for future Mars missions.  They are now
talking of manned flights in 2010 to 2017, about a decade after their
previous discussions of a late 1990's manned mission to Mars orbit.
     More information has come out about the Mir station space walk held
on June 30th.  Titov and Manarov tried to repair the British/Dutch
X-ray telescope during a 5 hour space walk, but ran into problems when
some of the tools they were using broke in the "cold of outer space".  This
suggests that they employed their standard tools from inside for park of this
work (ie. not EVA rated).  They are preparing for another space walk,
though no date is set.
     At the Soviet Party Congress last week there were two people who attacked
their space program.  As here the two lines of arguments were that it is
(a) expensive and the money could best be spent helping the people or (b) it
is a big science project which eliminates smaller, more worthwhile science
programs.  In spite of that it appears that the space program still has the
support of the leadership there.  However now those doubts are being expressed
publicly, so maybe this is what will finally slow them down.  On the
other hand it may drive the Russians towards faster implementation of space
processing on an industrial scale.  That would return materials both to their
economy and provide high tech, high value exports.  Unfortunately for the
time being there is little chance that such space processing will be done
by this country on an industrial scale.  We should work towards changing that.

                                                   Glenn Chapman
                                                   MIT Lincoln Lab

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

Date:     Fri, 08 Jul 88 17:27:26 -0900
Reply-To: <[e-mail]>
Sender: <[e-mail]>
From: WARRIOR                          <[e-mail]>
Subject:  RE: SPACE Digest V8 #261

w; zkOJd

5t

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

Date: 8 Jul 88 18:03:01 GMT
From: hpda!hpcuhb!hpsel1![e-mail]  (Bob Campbell)
Subject: Re: Comment about science was Re: Rocket engine

If you are looking for a book that covers theory down to the operation
of a metal lathe, I think you will be looking for a while.  If you want
a book that covers the math and thoery, you could try and find a copy of
_Rocket Propulsion Elements_.

The title page lists the following information.

Sutton, George Paul
    Rocket propulsion elements.

    "A Wiley-Interscience publication."
    Includes bibliographical references and index.
    1.  Rocket engines.  I.  Ross, Donald M., 1916-
joint author.   II. Title.

TL728.S8  1976     629.134'354  75-29197
ISBN 0-471-83836-5

Hopefully a librarian or bookseller will know what that means, and yes
it was (is???) being used to teach AAE 439 at Purdue although it was
first published in 1949 and last updated in 1976.

Bob Campbell                Some times I wish that I could stop you from
[e-mail]        talking, when I hear the silly things you say.
Hewlett Packard                                    - Elvis Costello

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

End of SPACE Digest V8 #291
*******************