Date: Sat, 12 Sep 92 05:00:50 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #187 To: Space Digest Readers Precedence: bulk Space Digest Sat, 12 Sep 92 Volume 15 : Issue 187 Today's Topics: 20 Questions About the Delta Clipper Arstrong's Boots Galileo and Ulysses fact sheets How to build ion engine? Is NASA really planning to Terraform Mars? (8 msgs) One Small Step for a Space Activist... Vol 3 No 9 Relativity SSTO has been achieved (2 msgs) Terraforming Terraforming needs to begin now Weekly reminder for Frequently Asked Questions list 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: 11 Sep 92 14:26:08 GMT From: "Allen W. Sherzer" Subject: 20 Questions About the Delta Clipper Newsgroups: sci.space In article amon@elegabalus.cs.qub.ac.uk writes: >The DCX is a simple craft using off the shelf parts and well >understood technology. There may be some flight regimes in which >there is something to be learned, but I suspect there is not much >from a science viewpoint. Unlike other vehicles built in the past, >its design is not a research project. This is a skunkworks aviation >project whose only goal is operational hardware. The main thing learned from DCX will be the viability of the flip maneuver they use on re-entry. According to the NASA assessment of the Delta Clipper design there isn't enough in the database to tell if it will work. Allen -- +---------------------------------------------------------------------------+ | Allen W. Sherzer | "If they can put a man on the Moon, why can't they | | aws@iti.org | put a man on the Moon?" | +----------------------225 DAYS TO FIRST FLIGHT OF DCX----------------------+ ------------------------------ Date: Fri, 11 Sep 92 07:55:11 GMT From: Glen K Moore Subject: Arstrong's Boots Newsgroups: sci.space I was aked today a question by someone who hadn't even thought of all of the useful things I know about the moon. A typical non scientist! He asked me "What material was used to make Neil Armstron's boots?" He needed the answer for a lecture on ?? and was serious in his request. I don't know where on earth to look. Does anyone out there know the answer? gkm@cc.uow.edu.au Science Centre Fax: 61-42-213151 ------------------------------ Date: 11 Sep 92 11:47:47 GMT From: Keven Weber Subject: Galileo and Ulysses fact sheets Newsgroups: sci.space G'day all, I'm after copies of the Galileo and Ulysses fact sheets. If anyone has either of these could they send me a copy? Cheers. Keven. -- ----- Email: weberk@cs.curtin.edu.au ------------------------------ Date: Fri, 11 Sep 1992 08:37:29 GMT From: Nick Szabo Subject: How to build ion engine? Newsgroups: sci.space In article <1992Sep10.160445.1938@vicorp.com> ron@vicorp.com (Ron Peterson) writes: > >Could someone please describe to me how to build a practical ion rocket? >...platform that could lift itself in the air powered by a solar cell >or very small battery. I thought that perhaps a tiny ion motor >with a solar cell painted on its exterior might be capable of >lifting itself off the ground. The thrust-to-weight ratios for any know ion rocket are far too small to lift itself off the ground. They are currently used for stationkeeping, which requires only a very low thrust for a long duration. Breakthroughs in the technology would be most important for deep space transportation, which is very limited by the low exhaust velocity of chemical engines, and could also be useful in circularizing satellites from GTO to Clarke orbit. -- szabo@techbook.COM Tuesday, November third ## Libertarian $$ vote Tuesday ^^ Libertarian -- change ** choice && November 3rd @@Libertarian ------------------------------ Date: 11 Sep 92 09:16:57 GMT From: Nick Szabo Subject: Is NASA really planning to Terraform Mars? Newsgroups: sci.space In article rick@trystro.uucp (Richard Nickle) writes: >Adding water requires small robot probes to go retrieve ice >and move it to mars. The robots would attach themselves to the appropriate >piece of ice, and use the ice itself as reaction mass to move them from >wherever you got them (Saturn, the belt) to Mars, whereupon they would >fall onto mars and release tons of water. You just set up your ice-retriever >robot factory someplace convenient: Lunar orbit? The general idea of moving ice to Mars is good, but this is really the roundabout to go about it. By the time we've moved the ice into Earth orbit, then lunar orbit, then back to Mars, we will have used up over 95% of the ice (cf. the rocket equation and 200-300 s. Isp for the nuclear- or solar-thermal engines using water as reaction mass). Also, we need to process the ice with robot plants before it can be used for reaction mass, to remove the dust (which may be up to 50% of the content) and shape the ice into something dynamically stable (my design uses a cylinder). A better approach is to use the Jupiter-family comets. These can be nudged to intercept Mars with 1-2 km/s delta-v, using up less than 1/3 of the ice mass as propellant, and delivering the other 2/3 to the surface of Mars. Even better, the ice can be captured into Earth and Mars orbit and used for transportation between the two bodies instead of launching upper stages from Earth. Best of all, the ice can be used to transport even more robot plants to the comets, a bootstrapping process that can reduce the cost of deep space transportation by five orders of magnitude in two decades. The two big breakthroughs here are (a) the rocket engine can be very low power, thus low mass, and (b) the ice rockets have a near zero tankage factor, so that even if we use up 90% of the propellant the rest is payload. Alas, access to currently known Jupiter-family comets is marginal with chemical upper stages. Titan IV/Centaur can deliver about 1,000 kg to such a comet during a good launch window, but this is probably not enough for robot plants with current technology to make ice rockets of a sufficient size for these tasks. Here is where the ion rocket could come into play to open up the solar system; the nuclear-thermal rocket a la Timberwind would have a similar effect. It would also be a big breakthrough if we found ice closer, in the Apollo-Amor asteroids, Phobos, or Deimos; finding such ice is the most important task of space exploration. Process technology is also an important driver. -- szabo@techbook.COM Tuesday, November third ## Libertarian $$ vote Tuesday ^^ Libertarian -- change ** choice && November 3rd @@Libertarian ------------------------------ Date: 11 Sep 92 12:02:01 GMT From: Andreas Michael Weder Subject: Is NASA really planning to Terraform Mars? Newsgroups: sci.space >It's also laughable to look at "global warming" when a single volcanic eruption >kicks enough enough ash to DROP temperatures despite our many years of >unregulated environmental engineering, hmm? > A lot of the chemical waste we pollute the lower athmosphere with needs several years to reach the upper regions. >We also don't have enough of a dataset on our world to show what the "real" >temperature should be. I kid you not. Would you like to average in the ice ages >and the time before the DinosaurKiller impacted? > Even if some of the results of on-going research on the topic of global warming were wrong, would you like to bet on that? Even if all the waste we're producing wouldn't damage the environment at all: it's toxic and we're killing life forms by simply dumping it in the oceans or whatever. And that's a fact. If you disagree, watch the news. I mean: I'm not afraid that life in whole will disappear from this planet, but I'm quite sure that, if we continue like that, man will. >Besides, population growth is self-correcting. People who have nothing better >to do start little piss-ant wars and end up killing themselves off. > Support U.N. military force against Serbia ^^^^^^^^ Definitely. (Yawn) Andreas Weder aweder@inf.ethz.ch ------------------------------ Date: Fri, 11 Sep 92 15:49:50 BST From: amon@elegabalus.cs.qub.ac.uk Subject: Is NASA really planning to Terraform Mars? > Even if you ignore all the globe-threatening issues, *population* growth, > which you can *count on*, will still be one of our greatest challenges. > It will keep growing until it simply *can't* and that only happens when > world resources, particularly in food stuffs, become steadily taxed. Don't > kid yourselves, this is *going* to happen whether you like it or agree > with it. > Read some demographics books. Population has been shifting from high birth rate/high mortality to low birth rate/low mortality for over a century. Population growth follows and S curve because there is a social lag between the mortality decline and the change in desired family size. The US and Western Europe went through this shift at and before the turn of the century. The end result was not as disastrous because they started at a lower baseline population and the medical technology was just being developed. Ie, the transition was spread out enough to allow social change to more closely track the technological change. Much of the "Third World" got modern medicine almost as a step function and also started from higher population bases and lower education/technology bases. Nonetheless, country by country they are going through the transition to stability. The exception so far has been africa, which seems to have very stable social structures making large families desirable. Not to fear. It will change. Whether by conscious decision or by the four horsemen is their own decision to make. At the end of the transition, populations tend to show NEGATIVE growth rates. Many European countries have slowly declining populations, with the possible exception of Ireland. The US would show negative growth already but it is hidden by the large size of the legal and illegal immigration. Japan is facing a massive social security crisis in the next decade because it's population is also graying. They have a requirement for heavy automation because they face a lack of manpower. (The USA faces a similar crisis due to a demographic pulse caused by the post-World War II baby boom rather than the demographic turnover.) China is trying to weave its' way between the Scylla of population growth and the Charybdis of an elderly, nonworking population. Population growth at this time is (except for africa) mostly a momentum effect that will stabilize by 2020-2050 or so. That is the good news. The bad news is that the stable population level could be as high as 10-15 billion. ------------------------------ Date: Fri, 11 Sep 1992 15:40:51 GMT From: Nick Haines Subject: Is NASA really planning to Terraform Mars? Newsgroups: sci.space In article <1992Sep11.091657.19639@techbook.com> szabo@techbook.com (Nick Szabo) writes: In article rick@trystro.uucp (Richard Nickle) writes: >Adding water requires small robot probes to go retrieve ice >and move it to mars. The robots would attach themselves to the appropriate >piece of ice, and use the ice itself as reaction mass to move them from >wherever you got them (Saturn, the belt) to Mars, whereupon they would >fall onto mars and release tons of water. You just set up your ice-retriever >robot factory someplace convenient: Lunar orbit? The general idea of moving ice to Mars is good, but this is really the roundabout to go about it. By the time we've moved the ice into Earth orbit, then lunar orbit, then back to Mars, we will have used up over 95% of the ice You're misreading the idea: set up a factory in Lunar orbit which makes robots. Send the robots out to where the ice is. The robots take the ice directly to Mars. Do not pass Earth, Do not collect $200. The main purpose of the robots is to take ice to Luna, but the factory owner is _so_ generous (?!) that some go to Mars instead. [...] Best of all, the ice can be used to transport even more robot plants to the comets, a bootstrapping process that can reduce the cost of deep space transportation by five orders of magnitude in two decades. We'll see. Nick ------------------------------ Date: Fri, 11 Sep 92 16:02:55 BST From: amon@elegabalus.cs.qub.ac.uk Subject: Is NASA really planning to Terraform Mars? > You do not know there is no life on Mars or anywhere else other than Earth. > I don't see the relevance of arguing over the label of 'back yard'. I don't > think as a society, or even a planet, we have yet learned how to manage our > *own* planet, not even a *little*. Because of this I don't think we are > qualified to begin applying our ignorance to anther planet. > As the joke about the Lone Ranger and Tonto goes, when the Lone Ranger saw the indian war party on the hill, he turned to Tonto and said "We're in a heap o'trouble". To which Tonto replied: "What you mean, WE, white man?" My response to the above, is "What you mean, WE, ?" It is obvious this person will not be the one doing the terraforming. Now, at the moment this is all moot argument. But in about 50-100 years, my return question would be different and to the point: "And just HOW do you propose to stop me?" Oh, by the way .... I expect to be quite well armed.... ================================================================================ Give generously to the Betty Ford Home amon@cs.qub.ac.uk for the Politically Correct. Belfast, Northern Ireland ================================================================================ ------------------------------ Date: Fri, 11 Sep 92 16:26:18 BST From: amon@elegabalus.cs.qub.ac.uk Subject: Is NASA really planning to Terraform Mars? > Furthermore, the Club of Ignorance also ignores little things like A) > Technological Innovation is not static, B) Free-market economies stimulate the > development of more efficient use of resources and substitutes. > I might add that the Club of Rome types also refuse to consider extraterrestrial resources and energy. All of their simulations are based on closed, technologically static systems. This makes their models a waste of MIPS. I really don't think the eventual use of ETM's is questionable. The only possible argument between optimists and pessimists is whether the have a big impact in the next couple decades or whether it is a hundred or a thousand years in the future. Is there anyone out there dumb enough to make a bet that there won't be significant imports to Earth from Mars by 2992? PS: I think I'd win the bet if I lived even until 2050. ------------------------------ Date: Fri, 11 Sep 92 16:46:25 BST From: amon@elegabalus.cs.qub.ac.uk Subject: Is NASA really planning to Terraform Mars? > Here we are, with great difficulty even getting antennas to point in the > correct direction and this guy suggests that we can throw jillions > of tons of matter at a planet accurately. Yes indeed, really refreshing. > A) We don't seem to have been having any trouble getting things to go where we want them, even with multiple fly bys. B) Who cares where the antenna is pointing as long as the water hits the planet? C) Who cares if a few percent miss? D) This ain't 1992 that we are talking about The above comment is about as relevant as making a complaint in 1492 that horseshoes can't be made to survive a transcontinental trip across Eurasia... ------------------------------ Date: Fri, 11 Sep 92 08:55:06 PDT From: "UTADNX::UTDSSA::GREER"@utspan.span.nasa.gov Subject: Is NASA really planning to terraform Mars? In Space Digest V15 #180, Nick Szabo writes: >In article samw@bucket.rain.com (Sam Warden) writes: > >>The spread of terrestrial life to other now lifeless environments >>seems _very_ moral to me, even a moral imperative, given a possibly >>limited window of ability to do so. > >Even while perhaps disagreeing about the size of that window, I wholeheartedly >agree that this is a moral imperative, not "pollution" or "ruining the planet" >as the politically correct would have us believe. I'm not sure if I would call it pollution, but "moral imperative"? What kind of gods are you guys making up, anyway? >szabo@techbook.COM Public Access User --- Not affiliated with TECHbooks >Public Access UNIX and Internet at (503) 644-8135 (1200/2400, N81) _____________ Dale M. Greer, whose opinions are not to be confused with those of the Center for Space Sciences, U.T. at Dallas, UTSPAN::UTADNX::UTDSSA::GREER "Pave Paradise, put up a parking lot." -- Joni Mitchell ------------------------------ Date: 11 Sep 92 14:29:02 GMT From: "Allen W. Sherzer" Subject: One Small Step for a Space Activist... Vol 3 No 9 Newsgroups: talk.politics.space,sci.space In article jbh55289@uxa.cso.uiuc.edu (Josh 'K' Hopkins) writes: >ESA has also done studies of an Ariane Transfer Vehicle to do logistics for >Freedom. It has two advantages I see over either of the above suggestions. >First, its launched on a vehicle that, while still vaporware, is looking to be >done one time and inexpensive to launch. Second, if ESA does the resupply, we >don't have to pay anything. So we have yet another option. I don't care which one we use so long as it is the cheapest. Allen -- +---------------------------------------------------------------------------+ | Allen W. Sherzer | "If they can put a man on the Moon, why can't they | | aws@iti.org | put a man on the Moon?" | +----------------------225 DAYS TO FIRST FLIGHT OF DCX----------------------+ ------------------------------ Date: 11 Sep 92 11:39:01 GMT From: Hartmut Frommert Subject: Relativity Newsgroups: sci.space Shawn.McCarthy@p902.f349.n109.z1.fidonet.org (Shawn McCarthy) writes: >Ok.. you look like you know what ur talking about (considerably more than i do >anyway.. :> ) got a question: what if that train is moving just 5mph slower >than c (as measured from the station) and i run forwards at 6mph? According to >the train, i am moving at 6mph.. what does the station see? (or move a flag >foreward at that speed on the outside, so they can see it) ... when the object >(me or the flag) moves past c according to the station, what happens? or is that >a case of the train being shorter (from the station) so the speed really ISN'T >faster than c..? given: station velocity relative to observer: v_1 your velocity relative to station: v_2 --> your velocity relative to observer: v = (v_1 + v_2) / [1 + (v_1*v_2 / c^2)] i.e. v = (c+1 mph) / (1+6 mph/c-30 (mph/c)^2) = c - 4.99999968 mph which is clearly *slower* than c. -- Hartmut Frommert Dept. of Physics, Univ of Constance, P.O.Box 55 60, D-W-7750 Konstanz, Germany -- Eat whale killers, not whales -- ------------------------------ Date: Fri, 11 Sep 1992 11:11:05 GMT From: Hartmut Frommert Subject: SSTO has been achieved Newsgroups: sci.space kwp@wag.caltech.edu (Kevin W. Plaxco) writes: >[..] a lunar SSTO was an achievable >task in 1969. >But what about a martian SSTO? I have seen several discussions >about the logistics of a manned (or even unmanned return) mars >mission, but I have never seen a proposal for how to achieve >mars orbit after the mission has ended. How difficult will this be? I have seen Mars ascent descent vehicle (ADV) plans, some of which included a SSTO ascent stage, and some even being only 1-stage ADV, years ago. If I remember right, Wernher von Braun described a Mars ADV with SSTO ascent stage as early as the early 1950s; ok, that's out of date since it presumes a Martian atmosphere of much higher density than really present and therefore had a winged Mars lander. About 1969 there was probably also a technology for a Mars SSTO -- if one could only get there. As far as I noted there are both SSTO and TSTO Mars ascent stages under consideration now. -- Hartmut Frommert Dept. of Physics, Univ of Constance, P.O.Box 55 60, D-W-7750 Konstanz, Germany -- Eat whale killers, not whales -- ------------------------------ Date: Fri, 11 Sep 1992 13:10:26 GMT From: Nick Szabo Subject: SSTO has been achieved Newsgroups: sci.space In article <1992Sep10.211155.23609@cco.caltech.edu> kwp@wag.caltech.edu (Kevin W. Plaxco) writes: >As the subject line says, a Single Stage ascent To Orbit has been >But what about a martian SSTO? I have seen several discussions >about the logistics of a manned (or even unmanned return) mars >mission, but I have never seen a proposal for how to achieve >mars orbit after the mission has ended. How difficult will this be? It should be quite straightforward to build an SSTO for 1/3 gravity. We wouldn't want to do it any other way -- every tank we drop has to come from Earth, a very expensive proposition. Combinining a very reusable Mars SSTO with native propellant reduces the ongoing costs of shuttling to and from Mars orbit by several orders of magnitude, assuming a large market. The same craft could be used to hop all over the planet, greatly increasing mobility and exploration. It would help if the Earth and Mars SSTO's used the same propellant (CH4/LOX), but even an LH/LOX SSTO shouldn't be to hard to convert to Martian CH4/LOX, given the relaxed constraints of Mars' gravity well. -- szabo@techbook.COM Tuesday, November third ## Libertarian $$ vote Tuesday ^^ Libertarian -- change ** choice && November 3rd @@Libertarian ------------------------------ Date: Fri, 11 Sep 92 16:04:32 BST From: amon@elegabalus.cs.qub.ac.uk Subject: Terraforming > The athmosphere, as we all now, seems to be an enourmously complicated > system. It gets kicked out of balance due to meteor impacts, changes > to the angle of Earth's axis and the like. This is not relevant to Dr. Zubrin's thesis. > So if you would be able to heat up this system in a few decades it > probably wouldn't be stable at all. It would cool out, heat up > again and maybe would never ever find it's balance again. > I'm very suspicious if a "solution" to a problem like this turns out > to be a brute-force method. > This was not simulation, but a simple matter of temperature and pressure curves and the direction that things are driven. He showed that Mars is bistable and that as time goes on, the warming up of the sun is making it easier and easier to push it over the edge so that it will fall into the upper bistable state. His logic and charts seemed quite solid, but as I don't have a copy of my own to refer to, I cannot in good faith defend his thesis much better than this. We'll just have to wait until it show up in the literature somewhere. Oh, and it is most decidely NOT a brute force method. It is more like tweaking a parameter of a bistable feedback control system just enough to make it runaway into the the second state. And yes, if you read what I posted I noted that it would reverse if the atmosphere becomes O2 rich. It would become transparent and allow cooling. But the CO2 atmosphere supports positive feedback that keeps things warm enough to keep the CO2 gaseous. ========================================================================= Are PC owners Internet Challenged? Dale Amon,Queens University Belfast (!!!Incoming!!!!) ========================================================================= ------------------------------ Date: 11 Sep 92 09:38:00 GMT From: pete Subject: Terraforming needs to begin now Newsgroups: sci.space In article , jgj@ssd.csd.harris.com (Jeff Jackson) writes... > >On the wall of a nearby office is this neat picture of a planet with >large amounts of liquid water, but large portions of the land mass is >brown -- dry, relatively lifeless desert. How about some ideas on how >to terraform good old earth? Starting with the Sahara or Austrailia's >outback. > >I guess the hard part is getting fresh water to these regions. Here's >my wild, uneducated, naive silly idea for all ya'll to shoot holes in. >There's tons of sand in these deserts. You can use sand to make >glass, so, use all this glass to make huge solar distillation systems. >I'm envisioning long salt-water canals running from the Med. Sea, or >Oceans running hundreds of miles inland. Covering each canal is a >greenhouse that heats the water up and makes it evaporate. At the top >of the greenhouse, the vapor is collected and cooled of, and the resulting >distilled water is then pumped out into irrigation canals runing >perpendicular to the salt-water canals. > >Yes, I'm an idiot, but tell me why. Why won't it work? What *would* >work? > Jeez that's bizarre. I had that exact idea some 10 years ago, in detail. Plus a few more twists: use the glass to form solar mirrors to fire the glass factories, and use the fresh water to grow crops on the ground sheltered from direct sunlight beneath the evaporation panels. The vapour is condensed by cool sea water flowing into the system along the tops of the evaporators. I see 2 major problems with this scheme, besides labour: 1) glass requires lime, to lower its melting point, and yield a strong product. Also sand must be very white to yield transparent glass. 2) how do you pump the seawater cheaply? =========================================================================== Hey, Sahara Sandblast Inc., Pete Vincent yeah that's the ticket. ------------------------------ Date: 10 Sep 92 13:51:44 GMT From: Jon Leech Subject: Weekly reminder for Frequently Asked Questions list Newsgroups: sci.space,sci.astro,sci.space.shuttle This notice will be posted weekly in sci.space, sci.astro, and sci.space.shuttle. The Frequently Asked Questions (FAQ) list for sci.space and sci.astro is posted approximately monthly. It also covers many questions that come up on sci.space.shuttle (for shuttle launch dates, see below). The FAQ is posted with a long expiration date, so a copy may be in your news spool directory (look at old articles in sci.space). If not, here are two ways to get a copy without waiting for the next posting: (1) If your machine is on the Internet, it can be obtained by anonymous FTP from the SPACE archive at ames.arc.nasa.gov (128.102.18.3) in directory pub/SPACE/FAQ. (2) Otherwise, send email to 'archive-server@ames.arc.nasa.gov' containing the single line: help The archive server will return directions on how to use it. To get an index of files in the FAQ directory, send email containing the lines: send space FAQ/Index send space FAQ/faq1 Use these files as a guide to which other files to retrieve to answer your questions. Shuttle launch dates are posted by Ken Hollis periodically in sci.space.shuttle. A copy of his manifest is now available in the Ames archive in pub/SPACE/FAQ/manifest and may be requested from the email archive-server with 'send space FAQ/manifest'. Please get this document instead of posting requests for information on launches and landings. Do not post followups to this article; respond to the author. ------------------------------ End of Space Digest Volume 15 : Issue 187 ------------------------------