Date: Thu, 29 Oct 92 05:01:19 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #354 To: Space Digest Readers Precedence: bulk Space Digest Thu, 29 Oct 92 Volume 15 : Issue 354 Today's Topics: A career in the Space Program - or Forget It!? active planetary probes; should someone update the FAQ (2 msgs) Apollo - Southern Style with a side of grits (2 msgs) Comet Collision (2 msgs) Re:Swift-Tuttle Comet a threat to earth? (2 msgs) Recognizing a Dyson sphere if you saw one Sen. Al Gore on the American Space & Aeronautics Programs Show from P/Swift-Tuttle in 2126? Smith-Tuttle Comet a threat to earth? (2 msgs) Solar Sails (2 msgs) Strategy for new generation of telescopes UN Space/Moon Treaty? 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: 28 Oct 92 22:04:28 GMT From: "Michael V. Kent" Subject: A career in the Space Program - or Forget It!? Newsgroups: sci.space In article romachek@golem.ucsd.edu (Jack Romachek) writes: > >>It all depends on you. If working in Aerospace is of such high intrinsic >>value to you, then you should push for it and nothing else, but ya got to >>be willing to go anywhere for it.... > >Sounds like a search for the Holy Grail... Basically, it is. If you don't have the drive, the ambition, the will to wrap your whole life around it, stay out of aerospace. Or you'll get burned. Mike -- Michael Kent kentm@rpi.edu McDonnell Douglas Rensselaer Polytechnic Institute Tute Screwed Aero Class of '92 Apple II Forever !! ------------------------------ Date: Wed, 28 Oct 92 18:40:32 GMT From: Doug Davey Subject: active planetary probes; should someone update the FAQ Newsgroups: sci.space In article , henry@zoo.toronto.edu (Henry Spencer) writes: > > Actually, I exaggerate slightly... Hiten has one science instrument, a > German dust detector, which has been returning some interesting results: ^^^^^^^^^^^ My goodness. A detector that can determine the country of origin of dust. > > --------- > 11.05 Iglseder H.* Grun E. Munzenmayer R. Svedhem H. > Cosmic Dust and Beta-Meteoroids in the Earth-Moon System: More > Than Two Years of Operation of the Munich Dust Counter MDC ^^^^^^^^^^^ Heavens! This thing really is specialized. It only counts dust from Munich. Ironically, from the rest of the report, we learn that the instrument only found "cosmic dust". This must have been a great disappointment to its designers. :-) :-) :-) -- +--------------------------------------------------------------------+ Doug Davey ddavey@iscp.bellcore.com bcr!iscp!ddavey ------------------------------ Date: Wed, 28 Oct 1992 20:01:17 GMT From: "J. I. Blackshear Jr." Subject: active planetary probes; should someone update the FAQ Newsgroups: sci.space There is also DSPSE (Deep Space Project Science Experiment) to be launched in Jan 94...it will do 2.5 phasing loops about the Earth and enter Lunar orbit on or about 21 Feb 94. It will stay in a 5 hour polar orbit with a periapsis altitude of about 425 km for about 65 days doing a complete surface mapping of the Moon using the following cameras UV/Visable Near Wave IR Long Wave IR High Resolution Visable once the mapping phase of the mission is up, we will depart the Moon and for a flyby of the near-earth asteroid 1620 Geographos on 31 Aug 94 as it crosses the ecliptic. -- Jim Blackshear jib@bonnie.jsc.nasa.gov ------------------------------ Date: 27 Oct 92 20:55:54 From: Wales.Larrison@ofa123.fidonet.org Subject: Apollo - Southern Style with a side of grits Newsgroups: sci.space Bill Higgins proclaims: >>>It worked, too. Southerners put us on the Moon. I don't think >>>Yankees could have done it in eight years. > >> At Lewis there is a persistant rumor that they could not have >>done it without some help from North of the Mason-Dixon line. >>Unfortunately I don't remember the details. Was it something >>about fuel type? or something about restarting engines in free- >>fall? |-) > > I suppose I owe the Clevelanders an apology (apollogy?) for my >glib overstatement. Heck, I'm a Great Lakes boy myself. Yes, >there were a lot of Yankees involved. But when the days of Apollo >are recounted, one hears a remarkable number of Southern accents >(including the mixed German-Alabama accents). And a few California drawls too, dude. They had something to do with the Saturn Second stage (North American - Seal Beach, California), and the F-1 and J-2 engines used on all of the Saturn stages (Rocketdyne - Canoga Park, California), and the Apollo Command and Service Modules (North American - Downey, California), and the LEM ascent engines (TRW -- Redondo Beach, California), and Skylab (McDonnell Douglas - Huntington Beach, California) and lots and lots of other parts. Let them Easterners argue about whose idea it was -- we know who really designed and built the thing.... :-) O.K., O.K., -- it was mostly SOUTHERN California. ;-) And when the days of Apollo are recounted, it'll probably go like this..... Picture an old, retired ex-aerospace engineer sitting in his rocking chair on his porch. His pocket protector, now faded yellow with age. Rocking back and forth, back and forth, surrounded by his grandchildren. "Gee granddad, did you REALLY work on the Apollo program?" "Yes grandson, I really did." "Gosh granddad, could you tell us about it?" "Certainly." The old, retired aerospace engineer fumbles under the blanket on his lap. He pulls out a slide projector remote control and a collapsible metal pointer. He pulls the pointer to full extension and thumbs the remote control on. The lights dim, a hidden projection screen drops into place, and he starts to explain... "Could I have the first vu-graph please??? ...." [Sorry guys, I couldn't resist. An semi-inside joke among some of us new-generation aerospace types. You'll get the punch line when you recognize you start automatically writing along the long axis on a pad of paper -- even when you're making up a grocery list. And start wondering why they put portrait mode in as an option in Aldus Persuasion and Microsoft Powerpoint. ;-) ] ------------------------------------------------------------------ Wales Larrison Space Technology Investor --- Maximus 2.00 ------------------------------ Date: 28 Oct 92 20:01:15 GMT From: "Allen W. Sherzer" Subject: Apollo - Southern Style with a side of grits Newsgroups: sci.space In article Wales.Larrison@ofa123.fidonet.org writes: >Bill Higgins proclaims: >>>>It worked, too. Southerners put us on the Moon... >>> At Lewis there is a persistant rumor that they could not have >>>done it without some help from North of the Mason-Dixon line... > And a few California drawls too, dude.... Well as long as everybody is claiming local credit let's not forget the Great State of Michigan. Home of the University of Michigan and the world's first degree program in Aeronautical Engineering. The local Bendix plant built the ALSEP packages which ran flawlessly on the moon for several years. Many of the parents of my childhood friends worked on that project. Alas they then lost their jobs when the last one flew :-(. You can find a list of major contractors in the 20th anaversary Appollo XI Press Kit available from the Smithsonian (or come to think of it from the Ann Arbor Space Society; I think we have some left). Allen PS. BTW, the first extra-terrestrial school reunion happened during Appollo 15 where the entire crew consisted of UM grads. -- +---------------------------------------------------------------------------+ | Allen W. Sherzer | "A great man is one who does nothing but leaves | | aws@iti.org | nothing undone" | +----------------------178 DAYS TO FIRST FLIGHT OF DCX----------------------+ ------------------------------ Date: 28 Oct 92 18:17:45 GMT From: "Bruce W. Morlan" Subject: Comet Collision Newsgroups: sci.space rsb@mcc.com (Richard S. Brice) writes: >> >> >There is a greater change of dying from a train wreck or a car accident than >> >getting plowed by the comet. >> >At the macro level, i.e. the interaction of planets, stars and comets, the >universe seems to behave in almost clocklike manner; chance and probability >have only a small role. ^^^^^ >Would anyone care to comment on how probability plays a role in the >future interactions of earth and comet P/S-T and how much of the >script is already written into the clock? Sure. The script is nearly totally written. The Heisenberg uncertainty associated with the objects in question (Earth, comet, Sun, other planets, etc.) is practically 0 over the time frame in question. On the other hand, the _uncertainty_ in the measurements leave much room for surprises. I cannot comment on the measurement errors. -- Bruce W. Morlan, Major, USAF Air Force Institute of Technology Dept. Department Head AFIT/ENC Department of Mathematics WPAFB OH 45433 ------------------------------ Date: 28 Oct 92 12:06:21 From: Steinn Sigurdsson Subject: Comet Collision Newsgroups: sci.space In article <1992Oct28.181745.11840@afit.af.mil> morlan@afit.af.mil (Bruce W. Morlan) writes: rsb@mcc.com (Richard S. Brice) writes: >> >> >There is a greater change of dying from a train wreck or a car accident than >> >getting plowed by the comet. >> >At the macro level, i.e. the interaction of planets, stars and comets, the >universe seems to behave in almost clocklike manner; chance and probability >have only a small role. ^^^^^ >Would anyone care to comment on how probability plays a role in the >future interactions of earth and comet P/S-T and how much of the >script is already written into the clock? Sure. The script is nearly totally written. The Heisenberg uncertainty associated with the objects in question (Earth, comet, Sun, other planets, etc.) is practically 0 over the time frame in question. On the other hand, the _uncertainty_ in the measurements leave much room for surprises. I cannot comment on the measurement errors. Well, there is a bit more to it, for example for comet interactions outgassing can be critical, particularly if the trajectory has a future close encounter predicted with outgassing neglected. A very small delta v at perihelion for very high eccentricity orbits can produce very large phase errors a hundred orbits later. With our current knowledge outgassing is unpredictable, I suspect it is a critical phenomenon and is intrinsically unpredictable, eg the cracking of crust due to superheated pockets of volatiles may literally depend on the radioactive decay of C-14 better, the exact time cracking may in principle be triggered by the decay of a single atom, for small enough pockets of gas ;-) So, wenting of gas and resulting delta v may be quantum mechanically uncertain at some level significant macroscopically... * Steinn Sigurdsson Lick Observatory * * steinly@lick.ucsc.edu "standard disclaimer" * * The laws of gravity are very,very strict * * And you're just bending them for your own benefit - B.B. 1988* ------------------------------ Date: 28 Oct 92 20:15:43 GMT From: Thorsten Altenkirch Subject: Re:Swift-Tuttle Comet a threat to earth? Newsgroups: sci.astro,sci.space I understand that it is pretty unlikely that Swift-Tuttle will hit earth in 2126. However, I would like to know what would happen in the case such a big object would collide with our planet? I am not sure whether my memory is right but in the discussion about the disappearance of the dinosaurs an object of a size like 200m was mentioned. Now, Swift-Tuttle is supposed to be much bigger (10 km?)... -- Thorsten Altenkirch And there's a hand, my trusty fiere, Laboratory for Foundations And gie's a hand o' thine, of Computer Science And we'll tak a right guid-willie waught University of Edinburgh For auld lang syne! ------------------------------ Date: 28 Oct 92 13:26:35 From: Steinn Sigurdsson Subject: Re:Swift-Tuttle Comet a threat to earth? Newsgroups: sci.astro,sci.space In article alti@dcs.ed.ac.uk (Thorsten Altenkirch) writes: I understand that it is pretty unlikely that Swift-Tuttle will hit earth in 2126. However, I would like to know what would happen in the case such a big object would collide with our planet? I am not sure You die, I die, Everybody dies! whether my memory is right but in the discussion about the disappearance of the dinosaurs an object of a size like 200m was mentioned. Now, Swift-Tuttle is supposed to be much bigger (10 km?)... Nah, P/Swift-Tuttle is barely a dinosaur killer with worst case diameter estimates - if you assume low albedo it is 10 km across, likely it is a little smaller, not quite enough to kill 50%+ of species, more of a civilization killer and 10% extinction (of species, higher fraction of individuals would die). So figure a few billion humans and complete death on continent scale depending on where it hit. | Steinn Sigurdsson |I saw two shooting stars last night | | Lick Observatory |I wished on them but they were only satellites | | steinly@lick.ucsc.edu |Is it wrong to wish on space hardware? | | "standard disclaimer" |I wish, I wish, I wish you'd care - B.B. 1983 | ------------------------------ Date: 28 Oct 92 22:24:05 GMT From: train@ccwf.cc.utexas.edu Subject: Recognizing a Dyson sphere if you saw one Newsgroups: sci.astro,sci.space In article max@west.darkside.com (Erik Max Francis) writes: >train@ccwf.cc.utexas.edu writes: > >> I may be wrong about this, I forget the aprroximate size of a dwarf star and >> wouldn't be anything near the size of a dwarf star would it? I thought dwarf >> stars, at least white dwarfs, were about the size of the Earth. > >"Dwarf" usually means main-sequence dwarf, which is the same class of >star that the Sun is. Main-sequence stars can be all sorts of sizes, >ranging from very large and massive O or B stars to very dim and cool M >stars. Our sun, a G2 V main-sequence star, is above average, though. > Yes - these things I already know. I was trying to make a point to the original writer of the original post (wherever is is now) that a sphere with the radius of the earth's orbit (1AU) won't be a dwarf as he/she (i forget) thought it might be. If it has a radius of 1AU, the star would be a giant or supergiant. -- ******************************************************************************* * "My neural pathways have become accustomed | Alton R. Pouncey II * * to your sensory input patterns." | train@ccwf.cc.utexas.edu * ******************************************************************************* ------------------------------ Date: Wed, 28 Oct 1992 20:48:50 GMT From: "Dr. Norman J. LaFave" Subject: Sen. Al Gore on the American Space & Aeronautics Programs Newsgroups: sci.space In article <1992Oct28.183409.1621@iti.org> Allen W. Sherzer, aws@iti.org writes: >In article <82350@ut-emx.uucp> wolfone@ccwf.cc.utexas.edu (Patrick Chester) writes: > >>= STATEMENT BY SENATOR AL GORE >>= Goddard Space Flight Center >>= Monday, October 19, 1992 > >>Gore butters up spaceflight enthusiasts, flem at eleven. > >Actually, Gore is buttering up Shuttle enthusiasts. In the first part of >his speech he talks about reducing the cost to orbit but when you get to >where he plans to spend the money, it's all for Shuttle. There will be >no money for cutting costs but plenty of pork. > >>= I'm talking from first-hand experience. As Chairman of the Senate >>= subcommittee that writes NASA's authorization bill, I have battled >>= every year with the Administration on priorities in aerospace. > >>What is his REAL record? Anyone? Back to our sound bite. > >Not good. Gore was at the forfront of people working to protect Truly >when he was fired. His efforts on his sucommittee shows that he simply >doesn't care about space very much (asside from Mission to Planet Earth. > >>Maybe NASA's budget should be increased a bit more. At least cut the pork from >>all of their projects. > >From Gore's statements and actions one must conclude that he opposes 'better, >cheaper, faster' and therefore won't increase budget or reduce pork. > >>= Right to the point, Dan Quayle and the National Space Council >>= have failed to act decisively on the issue of developing a new rocket >>= program. The blame must lie squarely at their feet. > >>He may have a point here. > >Quayle and the Space Council have shown tremendous leadership on new >launch programs. SSTO for example, wouldn't have happened without the >personal interest of VP Quayle. > >Gore doesn't have a point here. > >>= As proposed by the Space Council, the U.S has been actively >>= attempting to develop not one, not two, but three -- yes, three new, >>= costly, and technically complex orbital launch systems: > >First, Gore shows here that he simply doesn't understand science or >engineering all that well. If he did he would know that the best way >to cut costs is to fund several efforts. > >Second, all together I agree that NLS is a bad idea we could develop >ALL these ideas for about 15% of NASA's budget. Given that this is >the sort of research NASA is chartered to do, it hardly seems costly. > >>= Plane, and the Single Stage Rocket Technology program, which still >>= has no price tag. > >>Allen, could you enlighten everybody to the Delta Clipper's price, please? > >DC-Y should cost $2 to $4 billion with another billion or so needed beyond >that to take to market. Over four years it is hard to see why Gore >could possibly consider this costly. > >>= even given the fact that the Space Plane and the Single Stage >>= Technology program may provide significant benefits only in the >>= long-term future. > >>I don't know about the NSP, but DC-X is going to be test-flown in a few months. >>Guess long-term to Gore is anything longer than 4 years. > >NASP is a long term research effort. It's a pity that Gore considers long >term research a bad idea. > >SSRT is a moderate risk high payoff project which, if it works, will >reduce costs by an order of magnitude during a Clinton administration. > >>= The findings of the Advisory Committee on the Future of the U.S. >>= Space Program, the so-called "Augustine Committee", offer a good road >>= map. > >Which is very strange. The number one recommendation of the Advisory >Committee was that a Heavy Lift Vehicle (which he opposed above) >should be the highest priority for NASA. > >>My main bitch about waiting for manned exploration is that we've *been* waiting >>for nearly 20 yrs to start. At least let us return to the Moon, dammit. > >Any you will continue to wait under Clinton. > >If you loved NASA under Truly, your going to love the next 4 years. > > Allen I am a Clinton supporter and will continue to be a Clinton supporter because I believe he is the only candidate to have a clue about the nature of macroeconomics, the state of the health care system, the necessity of welfare and education reform, and a variety of other issues. Allen disagrees, and we have been engaged in debate in alt.politics.clinton. However, on this issue I must agree with him (don't get all mushy on me Allen :-) ). This statement by Gore shows a misconception of the needs and goals of the space program. I differ with Senator Gore on several points: 1.) SEI is the type of mission which NASA should be doing, providing the kind of technical challenges, scientific challenges, and excitement which NASA is in desperate need of. I contend that, given a less micromanaged/interfering approach by NASA and Congress, this program could be done cheaper than the stated estimates. I also contend that the benefits will far outweigh any cost estimates over the life-cycle of the program. This is the type of project which built our technical dominance in the first place. It is high-time we returned to our roots. 2.) NASP is more than the development of a launch system, it is a state-of-the- art hypersonic flight research program which will yield benefits to many other aerospace programs. Benefits are already being derived in material sciences, high-speed computation, fluid dynamics, heating analysis, propulsion, ..... If no vehicle is ever derived, these advances will be worth the effort and cost. 3.) SSTO provides this country the opportunity to corner the commercial launch market by having a vehicle which is fully recoverable, needs less hardware and manpower infrastructure to process the vehicle for launch, and which has much simpler operational processing requirements. Enough said. 4.) The space station program is in dire need of a heavy lift capability. We had one (Saturn V) and discarded it due to lack of foresight. NLS may have its problems, but a simple upgrade of our Titan and Delta rockets is an insufficient replacement. We need a flexible launch system which can be adapted to unforeseen changes in launch requirements, which takes advantage of advances in light weight materials, advanced propulsion, and other modern technologies. Our international competitors are building new launch systems which will eventually outstrip our abilities to compete by the simple use of upgrades. Unlike Allen, I am not making my voting decision based on this one issue when there are several other equally pressing issues for which the Clinton/Gore campaign has presented superior proposals (Allen will disagree here but that's life). However, I feel strongly that Senator Gore's statement is misinformed. Therefore, I have written a lengthy letter to Senator Gore through the Little Rock campaign heaquarters explaining the economic, scientific, and engineering realities of the situation in the space community. I, and others, have invited him to talk to us who are working down in the trenches. I strongly believe that Senator Gore's position is the result of consultations with clueless science policy advisors and upper-level NASA administrators who have been out of the engineering and science loop for so long that they have become incompetant to evaluate the technical and scientific needs of NASA. I recieved an encouraging preliminary response this morning and I am awaiting more information. Anyone who would like to provide some factual input from their own experiences can send it to me by e-mail. I believe that Senator Gore's position can be swayed if enough evidence is presented. Norman Dr. Norman J. LaFave Senior Engineer Lockheed Engineering and Sciences Company When the going gets wierd, the wierd turn pro Hunter Thompson ------------------------------ Date: 28 Oct 92 21:33:52 GMT From: Bill Goffe Subject: Show from P/Swift-Tuttle in 2126? Newsgroups: sci.space It seems that the discussion of the impact probability of P/Swift-Tuttle in 2126 has been beaten to death in an amazingly short time. Perhaps a more interesting question (at least until a better orbit is obtained some years hence) is what kind of show it will put on in 2126. Any idea of what the likely magnitude and observed tail length would be? Would it rank as one of the closest large comets? Any comparison to Halley in the early part of this century? Bill Goffe | vi taught me a lot about the design of bgoffe@seq.uncwil.edu | text editors - and the choices not to make. ------------------------------ Date: 28 Oct 92 20:14:25 GMT From: Gerald Cecil Subject: Smith-Tuttle Comet a threat to earth? Newsgroups: sci.space I just ran the Swift-Tuttle orbital elements through the Voyager Mac Planetarium program. Lock on the earth, zoom in to see the Moon and watch the comet race by. Very impressive if completely misleading (no forces). One thing to note: the time of perihelion passage in the IAU orbital elements needs to be ``tuned'', otherwise the comet crosses the Earth's orbit while we're quite far away. I arbitrarily changed if from 12/12.323/92 to 7/21/91 to increase the perceived threat (to keep my Astronomy class alert tomorrow!). This delay is along the lines suggested in article 92Oct27151516@topaz.ucsc.edu, steinly@topaz.ucsc.edu (Steinn Sigurdsson) who writes: >No, the delay is along the orbit, perturbations orthogonal to >the orbit are small, basically there is an uncertainty in the >aphelion and small outgassing at perihelion is effective in >shifting the period due to changes in the aphelion - note the limit >as eccentricity approaches 1 infinitesimal changes in perihelion >velocity can produce arbitary changes in period but not in >the nodes. --- Gerald Cecil cecil@wrath.physics.unc.edu 919-962-7169 Physics & Astronomy, U of North Carolina, Chapel Hill, NC 27599-3255 USA ------------------------------ Date: 28 Oct 92 21:44:02 GMT From: Jack Romachek Subject: Smith-Tuttle Comet a threat to earth? Newsgroups: sci.space >the time of perihelion passage in the IAU orbital elements >needs to be ``tuned'', otherwise the comet crosses the Earth's orbit while >we're quite far away. I arbitrarily changed if from 12/12.323/92 to 7/21/91 >to increase the perceived threat (to keep my Astronomy class alert tomorrow!). >Gerald Cecil cecil@wrath.physics.unc.edu 919-962-7169 >Physics & Astronomy, U of North Carolina, Chapel Hill, NC 27599-3255 USA Strange. I did a calculation using the orbital elements from IAU Circular 5636 and had the comet returning to perihelion on 17 Dec. 2127, when according to the circular should happen 11 July 2126. That is approximately the same time difference encountered above. Will including planetary perturbations cause the comet to arrive 17 months earlier than a strictly two-body (comet+sun) calculation? ----------------------- romachek@golem.ucsd.edu ------------------------------ Date: 28 Oct 92 19:04:49 GMT From: Henry Spencer Subject: Solar Sails Newsgroups: sci.space In article <1992Oct28.165504.15346@ptdcs2.intel.com> greason@ptdcs2.intel.com (Jeff Greason ~) writes: >radiation pressure seems 2-3 orders of magnitude too small to be useful >for drive. Recalling that F=P/c for light pressure, and that power >density P is roughly 1.4kW/m^2 at Earth orbit, you get a pretty trivial >4.7 MICRONEWTONS per square meter. Yes, that's the right sort of number. Solar sails have to be very big and very light, and they accelerate slowly. >Even if you are satisfied with 0.001G (0.01m/s^2) of acceleration, this >means your sail material must mass less than 0.5 GRAMS per square meter. >Is this feasible? ... About 0.14g/m^2 is feasible (50nm aluminum) even without going to exotic approaches like perforated sails. But in practice, first-generation designs usually settle for rather lower accelerations. -- 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: Wed, 28 Oct 1992 20:27:53 GMT From: Brad Whitehurst Subject: Solar Sails Newsgroups: sci.space In article <1992Oct28.165504.15346@ptdcs2.intel.com> greason@ptdcs2.intel.com (Jeff Greason ~) writes: >Well, so solar sails are just "driven by radiation pressure". I'd heard >that (as well as solar wind) before. > >However, If you look at the original post, you'll see my concern -- >radiation pressure seems 2-3 orders of magnitude too small to be useful >for drive. Recalling that F=P/c for light pressure, and that power >density P is roughly 1.4kW/m^2 at Earth orbit, you get a pretty trivial >4.7 MICRONEWTONS per square meter. > ... Well, I don't have any numbers, but don't forget the "solar wind" of particles streaming from the sun. I would think it would have a significant contribution. -- Brad Whitehurst | Aerospace Research Lab rbw3q@Virginia.EDU | We like it hot...and fast. ------------------------------ Date: 28 Oct 1992 14:19:33 -0800 From: Yossarian Yggy King Subject: Strategy for new generation of telescopes Newsgroups: sci.space,sci.image.processing I saw a talk last week by Dr. Geoff Hinton, and he mentioned that he'd been involved in some work (though maybe only peripherally, I'm not sure) on building neural nets to learn how to correct for optical defects in large lenses. I've probably got this wrong, but it was something like having the net learn the distortion parameters for each point on the lens, which are then corrected with a secondary lens that is distorted in real-time as the image is gathered to correct for the distortions in the primary lens. He said in passing that the neural-net corrected lenses rivaled the resolution of the Hubble scope. Obviously (I think) you can only correct for distortions, not attenuations, by the atmosphere ... once you've lost information you can't get it back. -- Yggy King | Thinking the world should entertain you leads to boredom UBC Comp Sci | and sloth. Thinking you should entertain the world leads B.C., Vancouver | to bright clothes, odd graffiti and amazing grace in Canada | running for the bus. -- Ann Herbert ------------------------------ Date: Wed, 28 Oct 1992 19:24:18 GMT From: Robert Nychka Subject: UN Space/Moon Treaty? Newsgroups: sci.space I am looking for information concerning the "Moon Treaty" or some sort of treaty drafted by the UN dealing with "...the Use of the Moon and Other Celestial Bodies". Specifically I'm looking for limitations on private exploration and exploitation of space, and if there are - if they are enforcable, and by whom? Thanx in advance. ROb Nychka. ------------------------------ End of Space Digest Volume 15 : Issue 354 ------------------------------