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Subject: SPACE Digest V10 #132

SPACE Digest                                     Volume 10 : Issue 132

Today's Topics:
         Re: Multiple IUS's (was Re: Shuttle-Centaur)
           Multiple IUS's (was Re: Shuttle-Centaur)
              Re: astrodynamic software
         NASA Headline News for 10/02/89 (Forwarded)
               The Moon vs. My Backyard
             Re: Shuttle-Centaur
               The Moon vs. My Backyard
----------------------------------------------------------------------

Date: 9 Oct 89 02:47:39 GMT
From: jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Multiple IUS's (was Re: Shuttle-Centaur)

In article <[e-mail]> [e-mail] (Brian Yamauchi) writes:
>Is it possible to attach multiple IUS modules together either
>side-by-side or in a multistage configuration?

Well, the original plan for Galileo was to use a three-stage IUS variant,
but that hit delays and technical problems that caused the switch to
Centaur.  [sigh]  (In fairness, weight growth on Galileo had also caused
the IUS people considerable grief somewhat earlier.)  Undoubtedly you
could stack IUSes, but that would definitely require some re-engineering
of things like attitude control and thermal management.  It would also
require on-orbit assembly, which NASA is oddly reluctant to use.
--
A bit of tolerance is worth a  |     Henry Spencer at U of Toronto Zoology
megabyte of flaming.           | uunet!attcan!utzoo!henry [e-mail]

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

Date: 8 Oct 89 18:41:32 GMT
From: rochester![e-mail]  (Brian Yamauchi)
Subject: Multiple IUS's (was Re: Shuttle-Centaur)

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>In article <[e-mail]> [e-mail] (Paul Rodman) writes:
>>... Seems like the correct approach
>>would be to have a Space tug (+ IUS on the probe too) to kick things
>>out of earth orbit. Refuel the tug from unmanned tankers, please.
>
>This would undoubtedly be the correct approach.  There is a small problem:
>the Tug died long ago and was not available.  Centaur was.

Is it possible to attach multiple IUS modules together either
side-by-side or in a multistage configuration?

This would seem to be a relatively easy way to get higher velocities
for interplanetary missions.

The disadvantage would be that it would require multiple launches to
get the IUS units into orbit, but this sounds preferable to
trajectories that add years to the flight time (i.e. VEEGA).

_______________________________________________________________________________

Brian Yamauchi                University of Rochester
[e-mail]        Computer Science Department
_______________________________________________________________________________

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

Date: 8 Oct 89 19:04:34 GMT
From: prism![e-mail]  (SCHREIBER, O. A.)
Subject: Re: astrodynamic software

In article <[e-mail]> [e-mail] (Rick Kwan) writes:
>
>    --    Is there any well-accepted public domain source code for
>    handling multi-body problems (like several planets orbiting
>    a star)?  (What do universities do for this?)
I have written some programs for multibody problems using
the Bulirsh Stoer method for integration of ordinary differential
equations.
(There are as many equations as the number of bodies, times
the number of dimensions, times 2 (for order 2, velocity
and position))
The Bulirsh Stoer method is very modern and simple and contains checks
for convergence. It is detailed along with FORTRAN and Pascal
source code in 'Numerical Recipes' Cambridge University Press by
Flannery, Press, Teukolsky, Vetterling, a very popular book on
campuses right now.

>    --    Any recent books on astrodynamics?  All my stuff dates back
>    to the mid-70s or earlier.  (I assume the principles haven't

I recommend the book by Bate, Mueller and White, Dover edition
(ten dollars) 'Astrodynamics'. I think they did a great job in
clarity and conciseness. Their notation is also very consistent
and leaves no room for ambiguity.

Good luck and have fun. I guess the big problems come
when one tries to do real time animation and/or computation.
The amount of computations vary all the time with the
convergence checks and iterations necessary to assure convergence
when for example two bodies come very close to each other.
Then, to synchronize the rendering of the results might be
tricky.

Olivier Schreiber [phone], Office of Computing Services
Georgia Institute of Technology, Atlanta Georgia, 30332
uucp: ...!{allegra,amd,hplabs,seismo,ut-ngp}!gatech!prism!ccsupos
ARPA: [e-mail]

--
Olivier Schreiber [phone], Office of Computing Services
Georgia Institute of Technology, Atlanta Georgia, 30332
uucp: ...!{allegra,amd,hplabs,seismo,ut-ngp}!gatech!prism!ccsupos
ARPA: [e-mail]

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

Date: 9 Oct 89 05:10:13 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Subject: NASA Headline News for 10/02/89 (Forwarded)

[I've been on travel, hence the delay in getting these to the net. -PEY]

-----------------------------------------------------------------
                          NASA Headline News
Monday, October 2, 1989                       Audio: 202/755-1788
-----------------------------------------------------------------
This is NASA Headline News for Monday, October 2, 1989...


The Flight Readiness Review for the STS-34 mission is underway at
Kennedy Space Center.  The review is scheduled to wrap up Tuesday
afternoon with the announcement of a firm launch date.  The
launch window for the mission opens at 1:29 P.M., Eastern time,
October 12.


An attempt by the Christic Institute and two other anti-nuclear
groups seeking a delay in the launch of the Galileo spacecraft by
the space shuttle Atlantis must be filed in Federal District
Court before Wednesday.  A NASA response to the suit is then due
by Friday morning.   The court hearing on the request for an
injunction is scheduled for October 10.


Aviation Week magazine says completion of Space Station Freedom
could be delayed until 1999, an additional delay of 18 months,
because of budget constraints.  The magazine also reports that
management of the space station program will be reorganized with
more control being shifted from the Reston, Virginia office to
Johnson Space Center in Houston and Marshall Space Flight Center
in Alabama.


Johnson Space Center named crews for five future space shuttle
missions on Friday.  Included in the crews is Dr. Mae C. Jemison.
She's the first black woman selected to fly.  Dr. Jemison will
conduct life sciences experiments on her June 1991 flight aboard
the orbiter Discovery.


And a group of 20 astronaut applicants arrives at Johnson Space
Center today.  They will undergo orientation, medical evaluations
and interviews.  It's the second of an five groups expected this
year at Houston.  The agency will select 15 to 20 candidates in
January.


A news briefing on the Cosmic Background Explorer mission
scheduled for launch in early November will be held Thursday at
1:30 P.M., Eastern time, at NASA Headquarters.  COBE will study
the origin and dynamics of the universe...including the theory
that the universe began about 15 millon years ago with a
cataclysmic explosion...the so-called Big Bang.   The briefing
will be televised on NASA Select TV.

              *             *          *            *

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

Here's the broadcast schedule for public affairs events on NASA
Select television.   All times are Eastern.



Thursday, October 5.....


      11:30 A.M.      NASA Update will be transmitted.

       1:30 P.M.      Cosmic Background Explorer news briefing
                      from NASA Headquarters.


All events and times are subject to change without notice.
-----------------------------------------------------------------
These reports are filed daily, Monday through Friday, at 12 noon,
Eastern time.
-----------------------------------------------------------------
A service of the Internal Communications Branch (LPC), NASA
Headquarters, Washington, D.C.

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

Date: 8 Oct 89 07:00:28 GMT
From: ibmpa![e-mail]  (nick szabo)
Subject: The Moon vs. My Backyard

In article <[e-mail]> [e-mail] (6079 Smith J) writes:
>
>In article <[e-mail]>, [e-mail] (nick szabo) writes:

>> What Apollo found in the lunar soil can be
>> found in any typical backyard on Earth, and I can find oodles of things in
>> my backyard that you can't find on the Moon.
>
>What are we doing piddling around the Florida swampland?  Nick should start
>a company to lease launching rights from his backyard.  Think of the reductio
n
>in fuel consumption!  :-)
>

Why the smiley?  If you are serious about the Moon, you should be
serious about my backyard.  Maybe I'll get a decent price for my
house from a Lunar Base fan.  After all, they seem to have hundreds
of billions to spend!  (Shucks, it's not really _their_ money--
minor detail   :-)

>What we need from the Moon is a bunch of raw materials in a gravity well
>a lot shallower than Earth's.  One mass driver and an orbital solar furnace
>can make a lot of insulation for a space station.  A refinery for metals
>would be helpful too.

How are we going to power the mass driver?  How are we going to get
it there?  How are we going to maintain it?  How are we going to get
the solar furnace there and set it up?  How are we going to extract materials
from the Moon?  How are we going to make the insulation?  How are we
going to install it on the space station?  What is the space station for
anyway and how much does _that_ cost?  (Oh, I know..the space station is
a "stepping-stone to the Moon"--sorry :-)  What are we going to use the
metals for and what do we have to do to manufacture them into the proper
parts?

No one has come up with any rigorous or economical answers to
these questions.  Until they do--and we have _working prototypes_,
not just whiz-bang computer graphics and paper studies--launching materials,
raw or otherwise, from Earth is a lot cheaper.

(NB1: liquid oxygen accounts for less than 20% of the mass of payloads
launched into space.  Liquid hydrogen, the only other major "raw material"
used in space, cannot be found on the Moon.  Both of these could be replaced
within the next 20 years for most uses by solar or nuclear electric power.
There is just no big gain here.  Let's start doing the arithmetic).

(NB2: The Space Studies Institute, unlike too many NASA projects, _has_
built some working prototypes, within the limits of the Earth environment
and remarkably small funding. Most notable is their mass driver.  But their
work is still very preliminary; 90%+ of the technology we need has not been
prototyped).

>Asteroids would be better, sure, but we haven't
>got any lying around so conveniently.

There are several discovered, and probably dozens of undiscovered, asteroids
closer energy-wise than the Moon.  For a tiny, tiny fraction of this
lunar base cost--less than 1%!--we could find these asteroids and
characterize their surfaces.  Let's start doing the arithmetic!

>I say we colonize the moon as soon as
>we can figure out what's there.

Really?  What if we find out there's nothing there?

>Map the joint thoroughly, pick the best spots
>for locations, and *build* it already!

What if there are no good locations?

We _have_ mapped the Moon pretty well--far better than any asteroid--
and we haven't found _any_ good locations.  No concentrated ores, no
volatiles, nothing of value.

I'd much rather buy swampland in Florida.  ;-)

There are many, many other locations in the solar system.  How about let's
go take a look at them?

"Wealth is when small efforts produce large results.
Poverty is when large efforts produce small results."
            Robert Allen

--
--------------------------------------------
Nick Szabo
uunet!ibmsupt!szabonj
These opinions are not related to Big Blue's

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

Date: 9 Oct 89 02:13:56 GMT
From: jarvis.csri.toronto.edu!utgpu!utzoo![e-mail]  (Henry Spencer)
Subject: Re: Shuttle-Centaur

In article <[e-mail]> [e-mail] (Roger Arnold @prodigal) writes:
>One method that was proposed was to fuel it from residual fuel in the
>ET.  (It's just as easy to carry the needed mass of Centaur fuel in
>the ET as in the Shuttle, since the ET can go all the way to orbit
>with the Shuttle, with a slight gain in net payload over the launch
>path that causes the ET to reenter in the Indian Ocean).

Unfortunately, there is a modest but noticeable *loss* in net payload over
the launch path that causes the ET to reenter in the *Pacific*... which is
the modern trajectory.  They no longer fly the "dip" maneuver for the
tank's benefit; it finally occurred to someone :-) that it was costing
them payload.

>2) It would have left the ET in LEO.  Horrors!  Poor little NASA
>   couldn't see its way to develop the systems needed to prevent
>   an uncontrolled ET reentry as its orbit decayed.

Well, just to be fair to NASA [hear that chorus in the distance:  "for a
change!" :-)], if one wants such a system to be highly reliable and
weigh very little (to avoid cutting further into the payload), it's
not a trivial job.
--
A bit of tolerance is worth a  |     Henry Spencer at U of Toronto Zoology
megabyte of flaming.           | uunet!attcan!utzoo!henry [e-mail]

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

Date: 8 Oct 89 06:38:42 GMT
From: ibmpa![e-mail]  (nick szabo)
Subject: The Moon vs. My Backyard

In article <[e-mail]> [e-mail] (Alan Kennington) writes:

>
>I would guess that the main question (as is well known) is whether the rocks
>on the moon have the right sort of elements in them. Required are carbon,
>hydrogen, oxygen, some sort of oxygen-diluter (inert gases don't form
>compounds very easily, but maybe there's a rock with nitrogen in it),
>compounds which can react to give intense heat (for melting rocks to get
>other things out of them).

This is, if you will pardon me, not a very important question. The answers
have been well-known since the late 60's.  Volatiles (hydrogen, nitrogen,
etc.) are very rare or nonexistent.  Almost everything else is there, but
very undifferentiated compared to Earth (no concentrated ore-forming
processes).

The important questions are, what can we make out of this stuff, do we
need it, how do we make it, and how do the economies compare to the
alternatives?  These questions are very tough, and only a few daring
souls (like Princeton's SSI) have been willing to tackle them.

>
>Where do you get this sort of basic information? - Especially the set of
>types of rocks on the moon, and their chemical composition.

Look in the astronomy library of your local university for papers on the
Surveyor/Zond/Apollo data.


"Always go into a deal anticipating the worst."
                Donald Trump

--
--------------------------------------------
Nick Szabo
uunet!ibmsupt!szabonj
These opinions are not related to Big Blue's

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

End of SPACE Digest V10 #132
*******************