Date: Sun, 28 Mar 93 05:10:49 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V16 #380 To: Space Digest Readers Precedence: bulk Space Digest Sun, 28 Mar 93 Volume 16 : Issue 380 Today's Topics: Gravity waves, was: Predicting gravity wave quantization & Cosmic Noise How to cool Venus Predicting gravity wave quantization & Cosmic Noise Space Ship - Outer Space Space Station Redesign: Constellation Speculation: the extension of TCP/IP and DNS into large light lag enviroments Terraforming Venus the call to space (was Re: Clueless Szaboisms ) Timid Terraformers (was Re: How to cool Venus) way off topic, Was something else Where do they get Ti slag from (3 msgs) 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: Sun, 28 Mar 1993 02:42:50 GMT From: Tom Van Flandern Subject: Gravity waves, was: Predicting gravity wave quantization & Cosmic Noise Newsgroups: sci.space,sci.astro,sci.physics,alt.sci.planetary crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes: > Bruce.Scott@launchpad.unc.edu (Bruce Scott) writes: >> "Existence" is undefined unless it is synonymous with "observable" in >> physics. > [crb] Dong .... Dong .... Dong .... Do I hear the death-knell of > string theory? I agree. You can add "dark matter" and quarks and a lot of other unobservable, purely theoretical constructs in physics to that list, including the omni-present "black holes." Will Bruce argue that their existence can be inferred from theory alone? Then what about my original criticism, when I said "Curvature can only exist relative to something non-curved"? Bruce replied: "'Existence' is undefined unless it is synonymous with 'observable' in physics. We cannot observe more than the four dimensions we know about." At the moment I don't see a way to defend that statement and the existence of these unobservable phenomena simultaneously. -|Tom|- -- Tom Van Flandern / Washington, DC / metares@well.sf.ca.us Meta Research was founded to foster research into ideas not otherwise supported because they conflict with mainstream theories in Astronomy. ------------------------------ Date: 28 Mar 93 02:07:38 GMT From: James Thomas Green Subject: How to cool Venus Newsgroups: sci.space It sounds like the idea of nukes at Venus is to heat the atmosphere and cause it to expand to beyond escape velocity. I thought of another, if slower way to accomplish the same thing. Huge solar mirrors could reflect and concentrate sunlight on Venus. The atmosphere would get hotter and thus expand until a large amount of it is gone. I leave it as an exercise to the interested how much surface area of mirrors and time would be required. A/~~\A ((O O))___ \ / ~~~ # # # (--)\ # --#---x---x---x---x---x---#---x---x----x----x---x---#---x---x---x---x---x---#--- # James T. Green # jgreen@oboe.calpoly.edu # \ # --#---x---x---x---x---x---#---x---x----x----x---x---#---x---x---x---x---x---#--- \#// \|/ \\\|||// \#/ \\\||/ \||/// \\#|// \\\\\|||/// \|/#\| O u t s t a n d i n g i n t h e f i e l d ! ------------------------------ Date: 27 Mar 93 02:19:32 GMT From: William Reiken Subject: Predicting gravity wave quantization & Cosmic Noise Newsgroups: sci.space,sci.astro,sci.physics,alt.sci.planetary In article <1993Mar26.161938.19354@ke4zv.uucp>, gary@ke4zv.uucp (Gary Coffman) writes: > > I could write a book on what I don't know about gravity waves. > Go ahead and do it. Maybe if you write such a book. Those who do know everything about them will have a better idea on what to write about. So in the end, it will help everyone. You could call it "What I don't know about gravity waves, by Gary Coffman" This is not a critical comment, no puns intended and no Joke, just a thought. Maybe those experts out there should think about it as well. Since this is a very difficult subject for most people to understand. Will... ------------------------------ Date: Sat, 27 Mar 93 21:31:30 EST From: John Roberts Subject: Space Ship - Outer Space -From: davidlai@unixg.ubc.ca (David Lai) -Subject: Space Ship - Outer Space -Date: 26 Mar 93 17:57:25 GMT -Organization: The University of British Columbia -Hi netters, - I remember that a spacecraft was around the nineth planet some -years ago. Is there any spacecraft travelling beyond the nineth planet -now? If so, what discovery has it make? Can it still communicate with -the Earth? Voyager 2 flew by Neptune, which was the ninth planet at the time (but usually isn't). Yes, DSN is still in contact with Voyager 2. John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: Sat, 27 Mar 1993 23:50:21 GMT From: Nick Szabo Subject: Space Station Redesign: Constellation Newsgroups: sci.space Let's step back and consider the functionality we want: [1] microgravity/vacuum process research [2] life sciences research (adaptation to space) [3] spacecraft maintenence The old NASA approach, explified by Shuttle and SSF, was to centralize functionality. These projects failed to meet their targets by a wide margin: the military and commercial users took most of their payloads off Shuttle after wasting much effort to tie their payloads to it, and the original SSF concept has failed in a jumble of disorganization and lack of end-user support. Over $50 billion has been spent on these two projects with no reduction in launch costs and little improvement in commercial space industrialization. Meanwhile, military and commercial users have come up with a superior strategy for space development: the constellation. Firstly, different functions are broken down into different constellations placed in the optimal orbit for each function: thus we have the GPS/Navstar constellation in 12-hour orbits, comsats in Clarke and Molniya orbits, etc. Secondly, the task is distributed amongst several spacecraft in a constellation, providing for redundancy and full coverage where needed. SSF's 3 main functions require quite different environments and are also prime candidates for constellization. [1] We have the makings of a microgravity constellation now: COMET and Mir for long-duration flights, Shuttle/Spacelab for short-duration flights. The best strategy for this area is inexpensive, incremental improvement: installation of U.S. facilities on Mir, Shuttle/Mir linkup, and transition from Shuttle/Spacelab to a much less expensive SSTO/Spacehab/COMET or SSTO/SIF/COMET. We might also expand the research program to take advantage of interesting space environments, eg the high-radiation Van Allen belt or gas/plasma gradients in comet tails. The COMET system can be much more easily retrofitted for these tasks, where a station is too large to affordably launch beyond LEO. [2] We need to study life sciences not just in microgravity, but also in lunar and Martian gravities, and in the radiation environments of deep space instead of the protected shelter of LEO. This is a very long-term, low-priority project, since astronauts will have little practical use in the space program until costs come down orders of magnitude. Furthermore, using astronauts severely restricts the scope of the investigation, and the sample size. So I propose LabRatSat, a constellation tether-bolo satellites that test out various levels of gravity in super-Van-Allen-Belt orbits that are representative of the radiation environment encountered on Earth-Moon, Earth-Mars, Earth-asteroid, etc. trips. The miniaturized life support machinery might be operated real-time from earth thru a VR interface. AFter several orbital missions have been flown, follow-ons can act as LDEFs on the lunar and Martian surface, testing out the actual environment at low cost before $billions are spent on astronauts. [3] By far the largest market for spacecraft servicing is in Clarke orbit. I propose a fleet of small teleoperated robots and small test satellites on which ground engineers can practice their skills. Once in place, robots can pry stuck solar arrays and antennas, attach solar battery power packs, inject fuel, etc. Once the fleet is working, it can be spun off to commercial company(s) who can work with the comsat companies to develop comsat replaceable module standards. By applying the successful constellation strategy, and getting rid of the failed centralized strategy of Shuttle and SSF, we have radically improved the capability of the program while greatly cutting its cost. For a fraction of SSF's pricetag, we can fix satellites where the satellites are, we can study life's adaptation to a much large & more representative variety of space environments, and we can do microgravity and vacuum research inexpensively and, if needed, in special-purpose orbits. N.B., we can apply the constellation strategy to SEI as well, greatly cutting its cost and increasing its functionality. MESUR and Artemis are two good examples of this; more ambitiously we can set up a network of native propellant plants on Mars that can be used to fuel planet-wide rover/ballistic hopper prospecting and sample return. The descendants of LabRatSat's technology can be used as a Mars surface LDEF and to test out closed-ecology greenhouses on Mars at low cost. -- Nick Szabo szabo@techboook.com ------------------------------ Date: Sun, 28 Mar 1993 00:25:18 GMT From: "Phil G. Fraering" Subject: Speculation: the extension of TCP/IP and DNS into large light lag enviroments Newsgroups: alt.internet.services,sci.space sean@ugcs.caltech.edu (M. Sean Bennett) writes: >>Why is it a dangerous precedent? Should NASA or the CIS be building bases >>that aren't under any jurisdiction? >It is my fault for not making myself clearer. >The Moon, Mars, etc. are "claimed for all mankind". >The dangerous precedent is the exporting of our national bigotries - irespective >of the nation involved. It's not really dangerous; what _is_ dangerous, is the regime you outlined above, which was implemented by the COPOUS Treaty. >What is this COPOUS treaty you speak of? A treaty that gave space "to all mankind;" literally, it gave _any_ nation on the face of the earth veto power over anything done by anyone up there. The death-squad-installed presidents of Honduras or Cuba would have just as much say in being able to stop space exploration as the heads of state of any other countries. In short, space exploration becomes even more of a hostage to tyrranical politicians, wheras in my opinion (which I do not think is humble, but is as close to absolute truth as humans get) it should not be hostage to any politicians at all. Go look up the COPOUS treaty and the debate surrounding it before you come back to flame. Please. >Sean -- Phil Fraering |"...drag them, kicking and screaming, pgf@srl02.cacs.usl.edu|into the Century of the Fruitbat." - Terry Pratchett, _Reaper Man_ ------------------------------ Date: Sat, 27 Mar 93 22:42:07 EST From: John Roberts Subject: Terraforming Venus -From: mrw9e@kelvin.seas.Virginia.EDU (Michael Robert Williams) -Subject: Re: How to cool Venus -Date: 26 Mar 93 17:17:28 GMT -Organization: University of Virginia -But, to the point, several people have been talking about using large -nuclear bombs (should that be "tools"?) to blast a large fraction of Venus's -atmosphere away. I read a really fascinating book a few years back called -"ThPhysical Principles of Thermonuclear Explosive Devices" that had a -chapter called "On Creating Thermonuclear Explosives of Arbitrarily Large -Size." It seemed pretty easy, at least conceptually; the author even says -something about blowing most of the atmosphere of the Earth away with a -suprisingly small bomb. -Does anybody with more experience in the field than I have (i.e. any at all) -have any idea if this sort of thing is truly possible, or was the author -improperly scaling his results? As you wisely point out, it's vitally important to try to plug in actual numbers to see if the idea makes any sense at all. I seem to have taken the results offline from the last time the math was worked out, but it came out as a really ridiculous expenditure of effort - the hydrogen bomb to do the job would make a pretty respectable moon. Paul Dietz may still have the calculations. It's not too hard to come up with a rough idea of the amount of energy required to do the job. First, calculate the total mass of Venus's atmosphere, which will be approximately the surface area multiplied by the surface pressure, divided by (Venus surface gravity / Earth surface gravity). Second, calculate the escape velocity from the surface of Venus (ignoring air resistance for the moment - that shouldn't matter because the effect of air resistance is to heat the atmosphere, and that's what you're doing anyway) - it should come out fairly close to Earth surface escape velocity. Third, use the formula E = 0.5 mv^2 to calculate the amount of kinetic energy that needs to be put into the mass of the atmosphere to accelerate it to escape velocity. That should be adequate for a first guess. You can subtract 1 or 2 percent from that number because you want to leave a some of the atmosphere there, but you probably have to add a large amount to account for inefficiency of the operation - the planet's crust will take up some of the energy. To calculate the mass of explosive material, you could start with antimatter - divide the amount of energy by the speed of light squared (~9E16 in SI units), then divide by 2 because antimatter annihilates an equal mass of ordinary matter. Unless I slipped a decimal point, that means you'd need on the order of hundreds of millions of tons of antimatter. Hydrogen fusion is far less efficient than antimatter (I don't have the number handy), so you'd have to multiply the antimatter mass by some large number if you want to do it with fusion. Anybody who still thinks it's a good idea can do the above calculations, then explain where they're going to get all that deuterium, tritium, etc. The idea of seeding the atmosphere with microorganisms to break down the carbon dioxide might be workable if there were other constituents in the atmosphere, but it doesn't seem practical with the atmosphere that's there. The surface and lower atmosphere are *much* hotter than any known Earth life can survive (proteins, the basic constituents, just aren't designed to operate at that temperature), so interaction with the surface materials isn't possible - the organisms couldn't trap the CO2 in the chemical structure of the rock. Just getting rid of the carbon and leaving the oxygen wouldn't be the answer either - at near-present Venus atmospheric pressure, oxygen would be far more deadly than the current CO2 atmosphere. It would be extremely difficult for organisms to survive at all in the atmosphere, because the atmosphere is *very* turbulent - particles floating at an altitude with survivable temperature would soon find themselves swept down to hotter regions. There *is* a possibility for terraforming - enormous numbers of large comets might be forced to collide with Venus, gradually blasting away the atmosphere and replacing the water Venus once had. There probably aren't enough comets in the planetary system to do the job, but you might be able to find them in the Oort cloud. The energy to shoot the comets to Venus directly would be prohibitive, but with very clever planning it may be possible to give the comets small nudges which will cause them (many years later) to interact with other bodies by collision or gravitational slingshot, and these secondary interactions would provide most of the energy (delta-V) needed to get the comets to Venus. You might even design the secondary interactions so that they cause tertiary interactions with even larger bodies, giving a multiplying effect. Humans might be able to manipulate sufficient energy to provide the fine guidance to keep all these bodies on track. However, there's a fundamental problem even with the colliding-comet approach - if humans are sufficiently powerful and skilled in space operations to manipulate large bodies in this way, then it would be an incredible waste to expend so much effort on Venus, because so many other useful things could be done. However you look at it, terraforming Venus just isn't worth it. You could probably build space colonies with aggregate floor space equal to the surface area of Venus for less effort than it would take to terraform Venus. The only way in which it might be worthwhile is as a novelty, at such time as humans become so powerful that it's a trivial effort and can be paid for out of petty cash - at which time we ought to get to other star systems and find planets that are easier to terraform. Of course, colonization is a different matter from terraforming. I've posted several ideas by which it ought to be possible to establish a robotic outpost or even a manned colony on the surface of Venus. It would be terribly expensive (orders of magnitude more expensive than a moon colony), and not worth much when it was done - perhaps it could be argued that it might be done out of scientific interest. John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: Sun, 28 Mar 1993 00:07:12 GMT From: "Phil G. Fraering" Subject: the call to space (was Re: Clueless Szaboisms ) Newsgroups: sci.space prb@access.digex.com (Pat) writes: >Will blats about how japan is going to rise again on a nuclear phoenix. >Please document the ROI for Nuclear Power, once all costs have been >allocated. >pat Simple. The Japanese trade deficit wrt Saudi Arabia is much much larger than their trade surplus wrt the United States. If the latter causes problems in the United States, which wrt "cultural values" has much more in common with Japan than Japan has with Saudi Arabia, can you imagine the political pressure they are under to find something better? _Especially_ since they're not going around pretending the mid-70's oil crisis never happened... Oh, you mean economics? Well, once you get rid of all the regulations that don't improve safety while increacing the cost and generally making the industry untenable (which may be their intended effect) nuclear is probably a pretty good deal... -- Phil Fraering |"...drag them, kicking and screaming, pgf@srl02.cacs.usl.edu|into the Century of the Fruitbat." - Terry Pratchett, _Reaper Man_ ------------------------------ Date: 27 Mar 93 02:28:25 GMT From: William Reiken Subject: Timid Terraformers (was Re: How to cool Venus) Newsgroups: sci.space Hey you guys, I have posted a question about Venus. I would like to know: ""What is the total composition of the Atmosphere of Venus?"" That means every little element, etc. ever detected in its Atmosphere. If you can give me the percentage ratios that would also be very welcomed. Will... ------------------------------ Date: 27 Mar 93 15:43:53 From: Steinn Sigurdsson Subject: way off topic, Was something else Newsgroups: sci.space,talk.politics.space,sci.energy Note redirected followups In article <1p261c$10g@access.digex.com> prb@access.digex.com (Pat) writes: Will blats about how japan is going to rise again on a nuclear phoenix. well, Japan is investing heavily both in conventional fission plants and breeders, although contending the opposition is governement controlled seems rather paranoid Please document the ROI for Nuclear Power, once all costs have been allocated. Japan has negligible internal oil or coal supplies, they are extremely vulnerable to embargoes and supply cutoff, with energy as with rice, I expect they will happily toss the Harvard business school attitude out the window and go with long term security of supply. * Steinn Sigurdsson Lick Observatory * * steinly@lick.ucsc.edu "standard disclaimer" * * But, oh, love is strange * * and you have to learn to take the crunchy with the smooth, * * I suppose - B.B. 1983 * ------------------------------ Date: 28 Mar 93 01:21:50 GMT From: schin@acs.bu.edu Subject: Where do they get Ti slag from Newsgroups: sci.space Hello Where do they get Titanium slag from. I know the end product goes on a variety of space product, but where does the ore itself come from Regards NEil ------------------------------ Date: Sun, 28 Mar 1993 01:58:44 GMT From: Jeff Bytof Subject: Where do they get Ti slag from Newsgroups: sci.space In article <113167@bu.edu> schin@acs.bu.edu writes: >Where do they get Titanium slag from. I know the end product goes >on a variety of space product, but where does the ore itself >come from From "General Chemistry", McQuarrie and Rock, pp. 894-895: "...The second most common transition metal is titanium, which constitutes 0.6 percent of the earth's crust by mass. Pure titanium is a lustrous, white metal. It is used to make lightweight alloys that are stable at high temperatures for use in missiles and high-performance aircraft. Titanium is as strong as most steels but 50 percent lighter. It is 60 percent heavier than aluminum, but twice as strong. In addition, it has excellent resistance to corrosion. The most important ore of titanium is rutile which is primarily TiO2. Pure titanium metal is produced by first converting TiO2 to TiCl4 and then reducing the TiCl4 by reacting it with magnesium. Most titanium is used in the production of titanium steels, but TiO2, which is white when pure, is used as a white pigment in many paints. Titanium tetrachloride is also used to make smoke screens; when it is sprayed into the air it reacts with moisture to produce a dense and persistent white cloud of TiO2." ["Deposits of rutile are found in Georgia, Virginia, Australia, Brazil, Italy and Mexico."] Question: what is the predominate mineral containing titanium on the moon? -rabjab ------------------------------ Date: Sun, 28 Mar 1993 02:25:30 GMT From: Paul Dietz Subject: Where do they get Ti slag from Newsgroups: sci.space In article <113167@bu.edu> schin@acs.bu.edu writes: > Hello > Where do they get Titanium slag from. I know the end product goes > on a variety of space product, but where does the ore itself > come from Titanium is obtained from various oxide minerals, such as ilmenite (FeTiO3), rutile and anatase (alpha- and beta- TiO2). These minerals occur in many places, including Australia, Russia, the USA, and elsewhere. Most titanium ore goes into making TiO2 for use as a pigment in paints and paper (it replaced lead compounds as the white pigment in paint.) Only a small amount goes into production of titanium metal. The market price of ilmenite concentrate is rather low, less than $.10/lb. Titanium metal is expensive because the refining process is expensive, not because the ore is rare or expensive. Paul ------------------------------ End of Space Digest Volume 16 : Issue 380 ------------------------------