Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V12_6/V12_724.TXT

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Subject: SPACE Digest V12 #724

SPACE Digest                                     Volume 12 : Issue 724

Today's Topics:
               Re: Interstellar travel
         NASA Headline News for 12/27/90 (Forwarded)
          Impact Cratering Numerical Computer Model

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Date: 24 Dec 90 20:40:16 GMT
From: cs.utexas.edu!news-server.csri.toronto.edu!utgpu!cunews!cognos!geovision![e-mail]  (Gord Deinstadt)
Organization: GeoVision Corp., Ottawa, Ontario
Subject: Re: Interstellar travel
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[e-mail] (Mark Gellis) writes:
>... I was just puzzled why so much is written
>about [anti-matter drives] and so little about fusion drives,
>for which there is
>the advantage of a huge fuel source in deuterium.)

With a fusion engine you should be able to make round trips by
refining the fuel from raw materials at the far end - stellar
atmosphere if nothing else.  Of course it would still be a century
or so for the round trip at 1/10th c.

Fusion engines are just the thing for travelling about in the solar
system.  Since the ideal reaction mass is 4 times the (payload+
structure) mass, there is no point in having a higher-density fuel.
You just have to carry more reaction mass to compensate for the
reduction in mass of the fuel.  Consequently, for efficient (minimum-
energy) operation, fusion is just as good as antimatter, provided
the fusion reactor can be made light enough.

Recently Paul M. Koloc of Prometheus II, Ltd. has been describing,
in sci.physics.fusion, his firm's plans for a very compact and energy-
dense reactor called a PLASMAK (tm).  If this works out it will give us
the engine we need for torch ships.  Of course it is a high-risk project
and they do not yet have the funding they need.

There is also the Migma system being developed by Bogdan Maglich, but
it may have difficulty providing the power density (Watts/kilogram)
required for space propulsion.  I wouldn't count it out, though -
once you're in orbit you can settle for pretty low acceleration,
and still get pretty decent transit times if your engine can fire
continuously.

There is the mainstream tokamak approach to fusion, and several
other approaches have been suggested but not developed or are still
in development.  I think one or more of these technological threads
will eventually lead to torch ships, and then the solar system will
be ours.  The nearer stars will take a few generations longer, if only
because of transit times.  Being able to flit freely about the galaxy
a la Star Trek will require new physics, if it can be done at all.
(Actually I think the physics of Dr. Who's TARDIS are more realistic
than those of the Enterprise.  Breakthroughs don't look just like
amplified versions of the past, any more than a car looks like a
horse or an airplane looks like a bird.)
--
Gord Deinstadt  [e-mail]

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Date: 28 Dec 90 01:22:04 GMT
From: trident.arc.nasa.gov![e-mail]  (Peter E. Yee)
Organization: NASA Ames Research Center, Moffett Field, CA
Subject: NASA Headline News for 12/27/90 (Forwarded)
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             Headline News
Internal Communications Branch (P-2) NASA Headquarters

  Thursday, December 27, 1990    Audio Service: 202 / 755-1788

This is NASA Headline News for Thursday, December 27, 1990

This is a summary of some of the most important activities and
developments which occurred in 1990.

The 1990 space flight year began in January with Columbia's
flight to retrieve the Long Duration Exposure Facility and ended
with Columbia's flight in December to carry out a long-awaited
astronomical observation mission with the first non-astronauts
to fly since the ill-fated flight of Challenger nearly 60 months
earlier.

National planning for the year began in February with Agency
chief Adm. Richard Truly launching an effort to collect the best
ideas on how to return to the Moon and go on to Mars.  Former
astronaut office chief Gen. Tom Stafford was named by Truly to
head the idea search.  Also in February, Truly formed a new
agency office out of the Office of Exploration and Office of
Aeronautics and Space Technology.  In July, Vice President Dan
Quayle announced the formation of the Advisory Committee on
the Future of the U.S. Space Program and named Martin
Marietta chief executive officer Norman Augustine to head it.  In
December that group reported its recommendations to Adm.
Truly and the White House.

The 1990 science year began in February with the Voyager 1
spacecraft taking a snapshot of nearly the entire family of
planets in our solar system .  In February, Galileo flew by Venus
in the first of three planetary gravitational assist maneuvers.  In
April, the Hubble Space Telescope was launched, only to have
discovered weeks later that its mirror system was ground to the
wrong formula.  Nevertheless, the Hubble telescope is fulfilling
its goal of providing unprecedented astronomical views.  NASA
announced a repair mission which would fly in 1993 and replace
the imaging instruments with optically modified new versions.
In June, the Roentgen Satellite was launched aboard a Delta to
begin its X-ray astronomy observations.  In July, the Combined
Release/Radiation Effects Satellite was launched aboard an
Atlas and began its investigations into the Earth's trapped
radiation belts.

By mid-summer, the Cosmic Background Explorer had
completed its initial all-sky survey of the background microwave
radiation left over from the Big Bang - providing confirmation of
the Big Bang theory but leaving cosmologists still pondering the
current complexity of the universe and how it became so.  In
August, Magellan went into Venus orbit and began its planet-
wide high resolution mapping mission.  In October, Ulysses was
launched on the first leg of its eventual solar polar orbit by
Atlantis.  In December, the Astro-1 shuttle Spacelab mission
flew for a 9-day astronomy observation mission with two non-
astronaut payload specialists aboard to help operate the science
instruments.  Also in December, Galileo flew by the Earth on the
second of its three-part planetary assist maneuvers.

The aeronautics year included celebration of the 75th
anniversary of the formation of the National Advisory
Committee for Aeronautics (NACA).  Experimental aircraft
flights this year included flight-testing of the swept-forward
wing X-29, which met with rave reviews from the test pilots, a
computer-assisted landing system which was flown on an
experimental Boeing 737 and laminar flow air control surfaces
which were tested on an experimental Boeing 757.  The National
Aerospace Plane program progressed through the year, first
with the merger of the five contractor teams into one national
contractor consortium in May and later with in the Fall with the
selection of a final configuration for the design -- a twin-tail
lifting body shape.

The following dates represent only a few of the Agency's
milestones for 1990:
1/9/90     Shuttle Columbia is launched to retrieve Long
     Duration Exposure Facility;
2/9/90     Galileo spacecraft flies by Venus at 9,300 miles
     altitude;
2/14//90 Voyager 1 takes portrait of Solar System;
2/28/90     Shuttle Atlantis is launched on a Dept. of Defense
     mission;
4/24/90     Shuttle Discovery is launched to deploy Hubble Space
     Telescope;
6/1/90     Delta 195 launches the Roentgen Satellite;
7/25/90     Atlas-Centaur-69 launches the Combined
     Release/Radiation Effects Satellite;
8/10/90     Magellan goes into Venus orbit;
8/28/90     Magellan begins high resolution mapping of Venus;
10/6/90     Shuttle Discovery is launched to deploy Ulysses
     spacecraft;
11/15/90 Shuttle Atlantis is launched on final secret Dept. of
     Defense mission;
12/2/90     Shuttle Columbia is launched for Spacelab Astro-1
     astronomy mission;
12/8/90     Galileo spacecraft flies by Earth at 620 miles altitude.

Here's the broadcast schedule for Public Affairs events on NASA
Select TV.  All times are Eastern.  **indicates a live program.

Thursday, 12/27/90

    11:30 am    NASA Update is transmitted;

    12:00 pm    Adm. Truly Holiday Message to NASA staff;

    12:30 pm    1990 Year in Review program;

    1:00 pm    Back Space series, "SkyLab";

    1:30 pm    Life Sciences at Manned Spacecraft Center.



All events and times may change without notice.  This report is
filed daily, Monday through Friday, at 12:00 pm, EST.  It is a
service of Internal Communications Branch at NASA
Headquarters.  Contact:  CREDMOND on NASAmail or at
202/453-8425.


NASA Select TV:  Satcom F2R, Transponder 13, C-Band, 72
degrees West Longitude, Audio 6.8, Frequency 3960 MHz.

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Date: 21 Dec 90 15:24:51 GMT
From: daffy!globey.cs.wisc.edu![e-mail]  (Gregory Carter)
Organization: U of Wisconsin CS Dept
Subject: Impact Cratering Numerical Computer Model
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     Hello!   Well, I recieved some interested peoples mail about
impact crater modelling, well, I got the thing done.  As soon as it
gets reviewed and chopped to bits, I was wondering if those people
who wrote to me could write or send a SASE to:

Greg Carter
2726 West Point Rd.
Green Bay,  WI 54304

You get C code, paper, and a disk, I only have the money to send three
replies, so whoever gets thiers here first gets 1 of the three replies.
(Disk is Mac Format, C code is Think C, Paper is PageMaker 4.0)

--Thanks!

--Gregory

PS: Paper being reviewed by Professor Robert Meyer, Geophysics department.
    I have found a computer science and math reviewer, but are awaiting
    their replies.

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End of SPACE Digest V12 #724
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