Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from beak.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests) ID ; Thu, 3 Jan 1991 20:45:51 -0500 (EST) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Thu, 3 Jan 1991 20:44:48 -0500 (EST) 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 Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription notices, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 24 Dec 90 20:40:16 GMT From: cs.utexas.edu!news-server.csri.toronto.edu!utgpu!cunews!cognos!geovision!gd@tut.cis.ohio-state.edu (Gord Deinstadt) Organization: GeoVision Corp., Ottawa, Ontario Subject: Re: Interstellar travel References: <3034@mentor.cc.purdue.edu>, <1707@ke4zv.UUCP>, <3039@mentor.cc.purdue.edu> Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu f3w@mentor.cc.purdue.edu (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 gdeinstadt@geovision.UUCP ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 28 Dec 90 01:22:04 GMT From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov (Peter E. Yee) Organization: NASA Ames Research Center, Moffett Field, CA Subject: NASA Headline News for 12/27/90 (Forwarded) Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu 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. ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 21 Dec 90 15:24:51 GMT From: daffy!globey.cs.wisc.edu!gcarter@speedy.wisc.edu (Gregory Carter) Organization: U of Wisconsin CS Dept Subject: Impact Cratering Numerical Computer Model References: <1990Dec20.230427.26838@jato.jpl.nasa.gov> Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu 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. ------------------------------ End of SPACE Digest V12 #724 *******************