Date: Sat, 10 Oct 92 05:03:03 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #304 To: Space Digest Readers Precedence: bulk Space Digest Sat, 10 Oct 92 Volume 15 : Issue 304 Today's Topics: (none) (2 msgs) ASTRONOMY CAMPS FOR TEENS AND ADULTS Drop nuc waste into sun (3 msgs) ENV SATELLITE SHUTDOWN IN DEC 1992 (3 msgs) Galileo Update - 10/09/92 Mass driver literature (was Re: Transportation on the Moon.) Pioneer Venus Briefing Set for Today SETI positive? (3 msgs) Transportation on the Moon. Welcome to the Space Digest!! Please send your messages to "space@isu.isunet.edu", and (un)subscription requests of the form "Subscribe Space " to one of these addresses: listserv@uga (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle (THENET), or space-REQUEST@isu.isunet.edu (Internet). ---------------------------------------------------------------------- Date: 9 Oct 92 17:39:41 GMT From: Herman Rubin Subject: (none) Newsgroups: sci.space In article <9210082138.aa27363@Bonnie.ics.uci.edu> syee@Bonnie.ICS.UCI.EDU writes: > >Subject: Re: Clinton and Space Funding > >In article hrubin@pop.stat.purdue.edu (Herman Rubin) writes: >> >>There is another, and extremely important, reason for colonization, namely, >>escape from an oppressive government. The Spanish colonies were moderately >>successful only where they were eminently profitable; the missions in >>California must be considered a failure. The French colonies in Canada >>and Louisiana were not particularly successful. On the other hand, the >>English colonies to escape oppression were generally quite successful, >>even bringing in others. A major part of the US immigration in the 19th >>century was to escape oppression. >I have one simple question. >If you're trying to "...escape from an oppressive government.", how are you >going to escape from this "oppressive government" when they're funding this >project? >Keep searching until a group of private corporations get together and fund a >majority of this project. You seem to have missed my other postings on this topic. I, and many others, have been advocating that the government allow private space expenditures AS THOSE WISHING TO SPEND THE MONEY WANT TO. At this time, it is illegal for an American to launch anything anywhere in the world without US government approval. Get the government out of restricting people, and the money can be raised by those who feel it worthwhile. We have some organizations now, and more can be formed, to get the job done. Exploration has been done by non-profit organizations as well as for profit, and quite a bit of it, and the various organizations can cooperate, much more easily than they can work through a government monopoly. The Planetary Society might fund unmanned exploration, there may be groups pushing for orbital work, for asteroid missions, etc. These groups are likely to share knowledge and expertise, but it would still be the case that each group would concentrate on funding what it felt to be important, without the need to get a consensus on priorities. For-profit companies would also invest in what they think will bring the returns. Of course speculation must occur; WE DO NOT KNOW, and we will not find out sitting on earth. -- Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907-1399 Phone: (317)494-6054 hrubin@pop.stat.purdue.edu (Internet, bitnet) {purdue,pur-ee}!pop.stat!hrubin(UUCP) ------------------------------ Date: 9 Oct 92 20:17:06 GMT From: "Michael V. Kent" Subject: (none) Newsgroups: sci.space In article hrubin@pop.stat.purdue.edu (Herman Rubin) writes: > >You seem to have missed my other postings on this topic. I, and many others, >have been advocating that the government allow private space expenditures AS >THOSE WISHING TO SPEND THE MONEY WANT TO. At this time, it is illegal for >an American to launch anything anywhere in the world without US government >approval. This isn't that unusual if you think about. I can't drive a car without the government's permission (driver's liscence), my car can't be driven off my property w/o govt's permission (lisence plates). I can't get married, go fishing or hunting (or flying!!) either. I can't do much of anything that might endanger society or some subgroup thereof. The difficulty of obtaining the proper lisence is proportional to the damage that could be done if something went wrong. Marriage and fishing lisences are easy to get, driver's lisences a bit harder, and pilot's lisences harder still. It shouldn't surprise anyone a lisence to launch several tons of high explosives over people's heads is even harder. Those who prove they can launch rockets safely can get a lisence. Both General Dynamics and McDonnell Douglas have one, and they can launch payloads without much further trouble. Sounds reasonable to me. It certainly has ample precedent. Mike -- Michael Kent kentm@rpi.edu McDonnell Douglas Rensselaer Polytechnic Institute All facts in this post are based on publicly available information. All opinions expressed are solely those of the author. Apple II Forever !! ------------------------------ Date: 9 Oct 92 18:55:56 GMT From: Jeff Regester Subject: ASTRONOMY CAMPS FOR TEENS AND ADULTS Newsgroups: sci.space,sci.astro,alt.sci.planetary The Steward Observatory Astronomy Camps for Adults and Teens for the coming winter, spring and summer have been scheduled. The dates are: Advanced Adult Camp Feb 18-21 Beginning Adult Camp Apr 23-25 Beginning Teen Camp Jun 7-14 Advanced Teen Camp Jun 18-25 The Astronomy Camps are run by Steward Observatory (Univ. of Arizona) as a non-profit educational outreach project. Attendees use the 40", 60", and 61" research telescopes of the Mt Lemmon and Mt Bigelow Observatories (north of Tucson) operated by NASA and Steward. A 16" Schmidt camera and numerous portable telescopes are also available. The Adult Camps are during weekends and consist of observing (using eyepieces, astrophotography with film and CCDs, and photometry, according to participant interest) and lectures, demonstrations, and discussions. Tours of research and engineering facilities, such as the spin-casting facilities of the Steward Observatory Mirror Lab, are also conducted. The Teen Camps (for ages 13 to 17) each last a week, four nights of which are spent observing. Activities include those of the Adult Camps plus tours of Kitt Peak facilities, science demonstrations, lectures (space program, archaeoastronomy, space art with Kim Poor, etc.) and other activities (model rockets, volleyball, orienteering in the mountains, etc.) For both Teens and Adults, the Advanced camps are for those who have previously attended a Beginning Camp or who have prior amateur astronomy experience. The Camps are run by Dr Donald McCarthy of Steward Observatory. Other Steward faculty and graduate students, as well as personnel of Flandrau Planetarium, participate as guest speakers and camp counselors. To receive more info about the Camps, contact either Don McCarthy voice: (602)621-4079 email: mccarthy@astro.as.arizona.edu usps: Steward Observatory, U of A, Tucson AZ, 85721 or Jeff Regester voice: (602)621-6535 email: regester@astro.as.arizona.edu usps: Steward Observatory, U of A, Tucson AZ, 85721 Jeff Regester counselor, U of A Astronomy Camps ------------------------------ Date: 9 Oct 92 21:22:46 GMT From: Pat Subject: Drop nuc waste into sun Newsgroups: sci.space Hey if this is stupid, please enlighten me. what if you sent a package on a venus gravity assist, but retrograde, so that the momentum transfer goes counter orbital direction, would that be cheaper then solar escape? a little gravity well, and bang you might have saved some money. let me know pat ------------------------------ Date: 9 Oct 92 21:17:19 GMT From: Don Roberts Subject: Drop nuc waste into sun Newsgroups: sci.space amon@elegabalus.cs.qub.ac.uk writes: [lots of interesting obital mechanics deleted] >If the nucleopaths on Earth won't agree to the best solution, which >is the hole in the ground on Earth, then the next best solution >might be a lunar hole in the ground. As long as we're asking and answering what are probably frequently asked questions, I'll ask one: Are there serious technical objections to dumping suitably "leak-proof" containers (i.e., whatever they plan to use in a Yucca Mt.-type repository) into a subduction zone at the bottom of the ocean? Assuming no leaks, we have a much cheaper version of the "dump it on Venus" or "dump it into the Sun" approach. Assuming small leaks *do* develop, the stuff would be pretty well diluted, yes? Personally, I prefer salt mines, or some other approach that allows us to keep an eye on the stuff, and have access to it if it ever proves useful. But it's a thought. Comments? I guess I should know the answer, but I'm a plasma physicist by training, and we can't produce enough radioactivity to make a good watch-dial...yet. -- Dr. Donald W. Roberts University of California Physicist Lawrence Livermore National Laboratory Recreational Bodybuilder dwr@llnl.gov Renaissance Dude The ideas and opinions expressed here do not represent official policies of Lawrence Livermore National Laboratory, the University of California, or the United States Department of Energy. ------------------------------ Date: Fri, 9 Oct 1992 22:37:37 GMT From: Paul Dietz Subject: Drop nuc waste into sun Newsgroups: sci.space In article <138588@lll-winken.LLNL.GOV> roberts@phoenix.ocf.llnl.gov (Don Roberts) writes: > Are there serious technical objections to dumping suitably "leak-proof" > bcontainers (i.e., whatever they plan to use in a Yucca Mt.-type repository) > into a subduction zone at the bottom of the ocean? It's a non-starter. First of all, subduction is very slow. Plates only move maybe 5 cm per year. So, in 10,000 years, the stuff has moved only 500 meters. It's not quickly sucked down into the mantle. Second, the sediments at a subduction zone are very active. They get scraped off and form "mud volcanoes" on the ocean floor. Not where you want to put waste. It would make more sense to put them far away from subduction zones, in the ocean floor, so that by the time they are subducted they are decayed away. But this is just sea-bed disposal, which has been considered for years. Paul F. Dietz dietz@cs.rochester.edu ------------------------------ Date: 9 Oct 92 19:47:52 GMT From: "Michael V. Kent" Subject: ENV SATELLITE SHUTDOWN IN DEC 1992 Newsgroups: sci.space In article rowland@zorba7.larc.nasa.gov (Michael W. Rowland) writes: >This is a repost of 6 Oct. posting (revised)... > > NUMBUS-7 > > Total Ozone Measurement System (TOMS) Is this real? NASA plans to shut down TOMS? Why? This is about the last instrument on the last satellite I expected to be voluntarily shut down. >Budget cuts are specified in House Conference Report 102-902 >that is attached to HR 5679, Sept. 24, 1992. I guess this is a likely explanation. Were these satellites mentioned by name or was it just a line item that got hacked to death? Mike -- Michael Kent kentm@rpi.edu McDonnell Douglas Rensselaer Polytechnic Institute All facts in this post are based on publicly available information. All opinions expressed are solely those of the author. Apple II Forever !! ------------------------------ Date: 9 Oct 92 20:14:56 GMT From: Henry Spencer Subject: ENV SATELLITE SHUTDOWN IN DEC 1992 Newsgroups: sci.space In article kentm@aix.rpi.edu (Michael V. Kent) writes: >> NUMBUS-7 >> >> Total Ozone Measurement System (TOMS) > >Is this real? NASA plans to shut down TOMS? Why? >This is about the last instrument on the last satellite I expected to be >voluntarily shut down. Bear in mind that there is a new TOMS now in orbit aboard a Soviet weather satellite. The one aboard Nimbus 7 is pretty old, although I believe it is still more or less working. -- MS-DOS is the OS/360 of the 1980s. | Henry Spencer @ U of Toronto Zoology -Hal W. Hardenbergh (1985)| henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Fri, 9 Oct 1992 20:44:55 GMT From: M22079@mwvm.mitre.org Subject: ENV SATELLITE SHUTDOWN IN DEC 1992 Newsgroups: sci.space In article rowland@zorba7.larc.nasa.gov (Michael W. Rowland) writes: > >This is a repost of 6 Oct. posting (revised)... > >We at Langley Research Center received news on Thursday, October 2, >1992 that NASA intends to shutdown the following satellites in >December to save about $15M: > > NUMBUS-7 > > ERBS > > NOAA-9 (partial?) > > NOAA-10 (partial?) > > UARS (SPRING 1993) > >Some of the following experiments that will terminate when >their satellites are shutdown are: > > Stratospheric Aerosol Measurement II (SAM II) > > Earth Radiation Budget Experiment (ERBS) (3) > > Stratospheric Aerosol and Gas Experiment II (SAGE II) > > Total Ozone Measurement System (TOMS) > > Halogen Occultation Experiment (HALOE) > > Microwave Limb Sounder (MLS) > >No plans have been stated to restart the satellites. > >Budget cuts are specified in House Conference Report 102-902 >that is attached to HR 5679, Sept. 24, 1992. > >Mike Rowland > >Mike Rowland, Aerosol Research Branch, MS 475 >NASA Langley Research Center, Hampton VA 23681 >internet: rowland@zorba7.larc.nasa.gov The UNOFFICIAL word I get is that NASA is dropping its direct downlink from the satellites listed in the previous post. The satellites previously listed were NOAA satellites and will continue to be managed by NOAA. It is however true that at least one NOAA satellite will be let go due to ground limitations when a new NOAA satellite is launched. - Karl J. Pitt ------------------------------ Date: Sat, 10 Oct 1992 04:32:50 GMT From: Ron Baalke Subject: Galileo Update - 10/09/92 Newsgroups: sci.space,sci.astro,alt.sci.planetary Forwarded from Neal Ausman, Galileo Mission Director GALILEO MISSION DIRECTOR STATUS REPORT POST-LAUNCH October 2 - 8, 1992 SPACECRAFT 1. During the period of October 3 through October 4, a navigation cycle was performed. This navigation cycle provided near-continuous acquisition of two-way doppler and ranging data during four consecutive passes of the spacecraft over DSS-63 (Madrid 70 meter antenna). This data will improve orbit determination in support of the TCM-15 (Trajectory Correction Maneuver #15) scheduled for October 9. 2. On October 5, a NO-OP command was sent to reset the command loss timer to 264 hours, its planned value for this mission phase. 3. On October 5, a routine sun vector update was performed. This sun vector is valid through October 27. 4. On October 5, an Ultra-Stable Oscillator (USO) test was performed to verify the health status of the USO and collect gravitational red shift experiment data; long term trend analysis is continuing. 5. On October 6, real-time commands were sent to temporarily configure the spacecraft telemetry rate to 1200 bps, which has not been sustainable since June 1991. On October 7, the spacecraft was configured to 40 bps uncoded telemetry and then back to 1200 bps on October 8. 6. On October 6, a periodic RPM (Retro-Propulsion Module) 10-Newton thruster maintenance activity was performed; 10 of the 12 thrusters were "flushed" during the activity. The P-thrusters were not flushed because they were used to perform science turn (SITURN) activities on the same day. Spacecraft performance throughout the activity was normal. 7. On October 7, the spacecraft performed a 14.5 degree SITURN. The purpose of the SITURN was to maintain the spacecraft within plus or minus 13 degrees of the sun while at the current solar distance. 8. On October 7, the Earth vector and Earth stars were updated to the spacecraft's present attitude. This change implements the attitude maintenance strategy required in the case of an AACS (Attitude and Articulation Control Subsystem) POR (Power On Reset). If a fault occurs which terminates the currently executing sequence, the spacecraft will maintain its current attitude. 9. On October 7, cruise science Memory Readouts (MROs) were performed for the Extreme Ultraviolet Spectrometer (EUV), Dust Detector (DDS), and Magnetometer (MAG) instruments. Preliminary analysis indicates the data was received properly. 10. On October 8, spacecraft telemetry maps were updated for the 1200 bps capability. 11. On October 8, the Trajectory Correction Maneuver (TCM-15) memory load was uplinked to the spacecraft. During the initial attempt, one of the eight TCM-15 messages was rejected by the spacecraft. The entire High Level Module (HLM) sequencing memory was readout, verified and the rejected message retransmitted and verified via memory readout. This commanding incident is under investigation. 12. The AC/DC bus imbalance measurements exhibited some change. The AC measurement has ranged from 12DN to 16DN and now reads 16 DN (3.7 volts). The DC measurement has ranged from 116 DN (13.5 volts) to 135 DN (15.8 volts) and now reads 126 DN (14.7 volts). These measurement variations are consistent with the model developed by the AC/DC special anomaly team. 13. The Spacecraft status as of October 8, 1992, is as follows: a) System Power Margin - 69 watts b) Spin Configuration - Dual-Spin c) Spin Rate/Sensor - 3.15rpm/Star Scanner d) Spacecraft Attitude is approximately 11 degrees off-sun (leading) and 16 degrees off-earth (lagging) e) Downlink telemetry rate/antenna-1200 bps (coded)/LGA-1 f) General Thermal Control - all temperatures within acceptable range g) RPM Tank Pressures - all within acceptable range h) Orbiter Science- UVS, EUV, DDS, MAG, EPD, and HIC are powered on i) Probe/RRH - powered off, temperatures within acceptable range j) CMD Loss Timer Setting - 264 hours Time To Initiation - 263 hours UPLINK GENERATION/COMMAND REVIEW AND APPROVAL: 1. The Trajectory Correction Maneuver (TCM-15) design package was approved by the Project on October 2, 1992. Additionally, the TCM-15 maneuver was approved for transmission by the Project on October 7, 1992. TCM-15 is a one portion maneuver scheduled to execute on October 9 consisting of one axial segment and one lateral segment. The estimated total delta velocity for TCM-15 is .716 m/s. 2. The EE-12 (Earth-Earth 12) Final Cruise Plan was approved by the Project on October 5, 1992. This sequence covers spacecraft activities from January 20, 1993 to April 12, 1993. 3. The Dual Drive Actuator (DDA) pulse mini-sequence No. 4 memory load was approved for transmission by the Project on October 8. This mini-sequence covers spacecraft activities associated with the DDA 10-pulse hammer test from October 12 to October 15. TRAJECTORY As of noon Thursday, October 8, 1992, the Galileo Spacecraft trajectory status was as follows: Distance from Earth 37,027,900 miles (.40 AU) Distance from Sun 125,287,800 miles (1.35 AU) Heliocentric Speed 61,600 miles per hour Distance from Jupiter 618,941,500 miles Round Trip Light Time 6 minutes, 44 seconds SPECIAL TOPIC 1. As of October 8, 1992, a total of 8237 real-time commands have been transmitted to Galileo since Launch. Of these, 3288 were pre-planned in the sequence design and 4949 were not. In the past week, 6 real time commands were transmitted and pre-planned in the sequence design. In addition, 5677 mini-sequence commands have been transmitted since March 1991; 3519 were pre-planned and 2158 were not. In the past week, no mini-sequence commands were transmitted. Major command activities this week included commands to reset the command loss timer, configure the spacecraft telemetry rate to 1200 bps, and uplink the TCM-15 memory load. ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Einstein's brain is stored /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | in a mason jar in a lab |_____|/ |_|/ |_____|/ | in Wichita, Kansas. ------------------------------ Date: 9 Oct 92 21:42:38 GMT From: Bill Higgins-- Beam Jockey Subject: Mass driver literature (was Re: Transportation on the Moon.) Newsgroups: sci.space In article <1992Oct9.174225.3103@uceng.UC.EDU>, rbatra@uceng.UC.EDU (Rajesh Batra) writes: > We have been given a Senior Design Project based on a fictious > premise that ice has been found at the North Pole of the Moon. Our moon base > (it's the year 2016, by the way) is located at the equator. Our Mission is > to bring back this ice from the North Pole to our production facility plants > (located at the equator as well) for extraction of Hydrogen and Oxygen. > [...] We have come up with several ideas including Pipelines, > Rockets, and Rail Guns. We are delivering about 2 tons of rock (containing ice) > a day. > > If anyone can direct me to abstracts that have been written concerning > Rail Guns please do not hesitate to email me. [I e-mailed Rajesh, but it seems this might be of interest to others, too.] Interesting design problem. Offhand, it seems wrong to drag the ice to the equator and do the processing there, but if that's your assignment... (Also, if you have the infrastructure to build a railgun launcher and associated power supply, logistics, operations and maintenance stuff at the poles, you can probably afford to build your chemical engineering plant there instead! Then you can ship anything you want anywhere on the Moon or beyond, using the same H2-O2 rockets you use to supply your base, refueling them at the Pole. Solar cells or mirrors on a tall tower can give you power 28 days around the clock there, too.) Hope Cincinatti has some good engineering libraries; if not, talk to your librarian about the Magic of Interlibrary Loan. And get a roll or two of dimes for the photocopier. Start with Arthur C. Clarke, "Electromagnetic Launching as a Major Contribution to Spaceflight," *Journal of the British Interplanetary Society*, v. 9 n. 6, November 1950, p. 261-267. Unless you want to start with an extremely obscure 1937 science fiction novel called *Zero to Eighty* by Akkad Pseudoman, a pseudonym (Oh, no kidding.) for E.F. Northrup. Generally speaking, the best places to look for information are the "Princeton Conferences," with titles like *Proceedings of the Nth Conference on Space Manufacturing*, published by the AIAA. I have the title of only one of them explicitly: *Space Manufacturing 5: Engineering with Lunar and Asteroidal Materials*, edited by Barbara Faughnan and Gregg Maryniak, AIAA (1985). Also, every couple of years, there is a big conference on electromagnetic launcher technology, and it appears in *IEEE Transactions on Magnetics* as an extra-thick issue. For instance, IEEE T on M, V.27, No. 1, January 1991. I have some specific early references (I met Henry Kolm in 1979 and he sent me a bunch of papers). Kolm, H., "An electromagnetic `slingshot' for space propulsion," *Technology Review*, Jun 1977, p. 61-66. Good semi-technical overview. Kolm, H., Mongeau, P., "An alternative launching medium," *IEEE Spectrum*, April 1982, p. 30-36. A bunch of papers in the first two Princeton Conference on Space Manufacturing (1977 and 1979) by Kolm, Kevin Fine, Peter Mongeau, and Fred Williams. Looking at my records, the Princeton conferences have so much stuff on this it's not worth typing the titles individually. O~~* /_) ' / / /_/ ' , , ' ,_ _ \|/ - ~ -~~~~~~~~~~~/_) / / / / / / (_) (_) / / / _\~~~~~~~~~~~zap! / \ (_) (_) / | \ | | Bill Higgins Fermi National Accelerator Laboratory \ / Bitnet: HIGGINS@FNAL.BITNET - - Internet: HIGGINS@FNAL.FNAL.GOV ~ SPAN/Hepnet: 43011::HIGGINS ------------------------------ Date: 9 Oct 92 21:51:04 GMT From: Duane F Marble Subject: Pioneer Venus Briefing Set for Today Newsgroups: sci.space,sci.astro,alt.sci.planetary Since it vanished "out of sight" I am waiting for the articles in National Enquirer, etc., about aliens snatching the vehicle. -- Duane F. Marble E-mail: dmarble@magnus.acs.osu.edu Department of Geography Telephone: (614) 292-2250 The Ohio State University Columbus, Ohio 43210 Fax: (614) 292-6213 ------------------------------ Date: 9 Oct 92 19:56:20 GMT From: Jeff Bytof Subject: SETI positive? Newsgroups: sci.space,sci.astro > Curiosity: why yellow? Don't main sequence orange and red stars last longer >than yellow ones? Is there some reson to think cooler stars than the sun won't >develop technological civilizations? The NASA targeted search will be looking at stars of spectral class F, G and K. M class red dwarfs (you don't want to mess with red giants!) would have much smaller ecospheres than the sun because they are less luminous, and therefore the probability of finding a habitable planet in the ecosphere of such a star would be very small. If a planet was in a red dwarf ecosphere, it might be close enough to the star to have its rotation tidally locked (which might have interesting implications for weather), though I'm not sure about that. > For that matter, wouldn't _any_ star system be a candidate for an >automated communications relay left by a self reproducing probe? A >paranoid might think another civilization would attempt to contact us >only through an offset communications device :). The NASA sky survey is designed to be complementary to the targeted search, though not quite as sensitive to weak signals. Automated probes may also be floating between the stars, perhaps in retrograde galactic orbits, passing by many more stars per unit time than if they following the general galactic rotation. -------------------- rabjab@golem.ucsd.edu ------------------------------ Date: 9 Oct 92 21:36:24 GMT From: Dave Nash Subject: SETI positive? Newsgroups: sci.space,sci.astro In article <1992Oct9.142810@IASTATE.EDU> danwell@IASTATE.EDU (Daniel A Ashlock) writes: > Curiosity: why yellow? Don't main sequence orange and red stars last longer >than yellow ones? Is there some reson to think cooler stars than the sun won't >develop technological civilizations? The red and orange guys _do_ last longer -- a lot longer, in most cases -- but as I (perhaps wrongly) understand it, really small stars (e.g., Proxima Centauri or Barnard's Star) are so feeble that a planet close enough to the star to receive enough energy from it to be Earthlike (warm enough for liquid water, e.g.) would become slowed by tides until its rotation period equals its year. Much like the case with our Moon, which is "locked" in this manner to the Earth. This means one hemisphere of the planet will permanently face the star and... well, you could guess the rest. An interesting book called _Habitable Planets for Man_ (I forget the author) makes a back-o'-the-envelope calculation of the sorts of conditions required for this, and concludes that the smallest star that can avoid the problems with tidal locking is a K2 main sequence star -- about like Epsilon Eridani, but much more luminous than red dwarfs, which are M class. This was, of course, a rough estimate, but if the tidal-locking idea is correct then it appears essentially all M (red) and most K (orange) dwarfs would not be the most suitable candidates for _originating_ extraterrestrial life. Any one out there with more knowledge of this possible problem? I only have the argument from this one book and I'm not sure if there are any more recent arguments for or against the tidal-locking idea. > For that matter, wouldn't _any_ star system be a candidate for an >automated communications relay left by a self reproducing probe? A Yeah, at least till it goes supernova or red giant (grin)... >Dan >Danwell@IASTATE.EDU -- David Nash | Gradual Student, Chemistry | University of Illinois (Urbana) (dnash@uxa.cso.uiuc.edu) | This .sig is made of 100% recycled electrons. (nash@aries.scs.uiuc.edu) | No binary trees were killed to make it. ------------------------------ Date: 9 Oct 92 21:58:57 GMT From: Jeff Bytof Subject: SETI positive? Newsgroups: sci.space,sci.astro >An interesting book called _Habitable Planets for Man_ (I forget the >author) Stephen Dole (and with Isaac Asimov wrote a less technical treatment "Planets for Man") Dole retired from the Rand Corporation in 1982. --------------------- rabjab@golem.ucsd.edu ------------------------------ Date: 9 Oct 92 21:04:42 GMT From: Jeff Bytof Subject: Transportation on the Moon. Newsgroups: sci.space > We are looking for any feasible transportation ideas that could >accomplish this task. We have come up with several ideas including Pipelines, >Rockets, and Rail Guns. We are delivering about 2 tons of rock (containing >ice) a day. My God, as far as we know the Moon's as dry as a bone, and we're talking about mining ice on it! Even if there IS ice, how do we know there's going to be enough to support whatever operation is proposed? My guess is that whatever ice there was at the Lunar poles has been blasted to Kingdom Come. --------------------- rabjab@golem.ucsd.edu ------------------------------ End of Space Digest Volume 15 : Issue 304 ------------------------------