Date: Thu, 13 Aug 92 05:02:34 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #105 To: Space Digest Readers Precedence: bulk Space Digest Thu, 13 Aug 92 Volume 15 : Issue 105 Today's Topics: beanstalk in Nevada Beanstalks in Nevada Sky (was Re: Tethers) Germans drop European Shuttle ? Parsecs? (4 msgs) Request: Sex in Space Solar System Journal (2 msgs) SPS feasibility (WAS: SPS fouling astronomy) 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: Wed, 12 Aug 92 18:58:25 PDT From: Eric_S_Klien@cup.portal.com Subject: beanstalk in Nevada Newsgroups: sci.space "I would suggest you drop the word orbit. There is no possible orbit that can put a satellite continuously over Nevada. None. Period. The only possibilities are solar sails and maglev devices that sit at least several thousand miles up. They would not be in free fall, they would be using an energy source to counter the acceleration due to Earth's gravity at that altitude." O.K. How much energy would it take to keep a casino hovering over Nevada at a height of 200 miles? Would there be any unusual stresses on the tether because the casino is hovering over Nevada? Eric Klien. ------------------------------ Date: 12 Aug 92 17:44:54 GMT From: "Michael K. Heney" Subject: Beanstalks in Nevada Sky (was Re: Tethers) Newsgroups: sci.space In article <1992Aug12.152900.19426@pixel.kodak.com> dj@ssd.kodak.com (Dave Jones) writes: > > [...] > >Clarke also had his tower made of that famous variety of unobtainium, >monomolecular filament. Assuming he'd done some basic estimates, you >have to figure that's the kind of tensile strength you need for a cable >23,000 miles long. He also had a captured asteroid stuck out on the >far end as a counter-weight, possibly at a height beyond GEO. > Don't forget the _2061: Odyssey Three_ approach - diamond. I know diamond is used in presses to generate pressures in the millions of atmospheres (in very *small* volumes), but is it actually strong enough to handle the tensile forces a GEO-centered tether would need to handle? Also, given a properly counterweighted system, so that the cm (or is it cg?) is at GEO, and the bottom of the tower nuzzles gently on the ground, wouldn't orbital perturbations really mess things up in a hurry? Given the masses we're talking about, stationkeeping would be quite a problem, no? Mike Heney | Looking for Senior level technical | Reach for the mheney@access.digex.com | and administrative positions world | Stars!!! Kensington, MD (near DC) | wide. Call me. | ------------------------------ Date: 12 Aug 92 10:38:46 GMT From: clements@vax.ox.ac.uk Subject: Germans drop European Shuttle ? Newsgroups: sci.space In article , pgf@srl02.cacs.usl.edu (Phil G. Fraering) writes: > writes: > >>Whilst skimming thru the TV channels last week, I caught sight of the >>German research minister, Riesenhuber, saying that Hermes was 'unacceptable' >>(not exact translation) to the German government in either manned or unmanned >>form. Two days later he showed up at the European Space Operations Centre to >>congratulate senior management on the fine job they'd done on Eureca. I'm >>cynical enough to believe that when politicians start throwing praise around, >>one should watch one's back. The ESA ministerial conference in November will >>probably contain some nasty surprises......... > > Hey! He's probably just tired of the way the French have shut down all > launch vehicle research besides Hermes/Ariane V in ESA... > > To wit, Saenger and Hotol... HOTOL and, as far as I know, Sanger were never properly adopted ESA projects. They were national or corproate schemes proposed to ESA as possible future launchers, which ESA didn't take up (mores the pitty). Sanger, I think, died there and then, but HOTOL continued as a British Aerospace project, though they had to drop Alan Bond's air breathing rocket motors since Rolls Royce, who owned the patent, refused to do anything without government/ESA support. Thus was born the Interim HOTOL, which would use a modified HOTOL airframe with conventional motors, lifted to altitude by an Antonov 225 (the plane tht carries bits of Energia around) also modified to give it extra thrust (extra engines added). This project was in conjunction with the USSR/CIS/whatever. Now, though, British Aerospace have closed down their Space Systems division in Stevenage, where the project was based, and so this scheme too would appear to have died. And thats the way the British 'space industry' operates. -- ================================================================================ Dave Clements, Oxford University Astrophysics Department ================================================================================ clements @ uk.ac.ox.vax | Umberto Eco is the *real* Comte de dlc @ uk.ac.ox.astro | Saint Germain... ================================================================================ ------------------------------ Date: Wed, 12 Aug 92 23:51:12 GMT From: Daniel Briggs Subject: Parsecs? Newsgroups: sci.space In article <1992Aug12.192659.7698@wixer.cactus.org> >The definition of a parsec is the distance at which the PARallax of an object >(star, galaxy, what have you) is one SECond. This distance is about 3.21 ^^^^^^ >light years if I remember correctly (Don't have any books near me to check >this). Hope this is helpful. arcSECond, please. Astronomy uses both time seconds and arcseconds. It's a bad habit to get into to use 'second' for both. Many an observation has gone down the tubes because these units were inadvertantly mixed up. Even the pros do it, if they are not careful. BTW, it's 3.26 light years to the parsec. You were pretty close. -- | Daniel Briggs (dbriggs@nrao.edu) | USPA B-14993 | New Mexico Tech / National Radio Astronomy Observatory | DoD #387 | P.O. Box O / Socorro, NM 87801 (505) 835-7391 | Support the League for Programming Freedom (info from league@prep.ai.mit.edu) ------------------------------ Date: 13 Aug 92 02:55:41 GMT From: Jim Carr Subject: Parsecs? Newsgroups: sci.space,sci.physics In article zowie@daedalus.stanford.edu (Craig "Powderkeg" DeForest) writes: > >This talk of parsecs and so forth reminds me of my favorite volumetric unit: >the barn megaparsec. > >A barn is a unit of atomic cross-section, 10^-20 cm^2. A barn megaparsec is >about 1.6 teaspoons! Cute, but I have always preferred the Hubble-barn. Granted, the exact value of the Hubble constant is not exactly agreed upon, but I like the fact that if you multiply the size of the universe (one uses the Hubble length, obviously) by 1 barn you get something like 16 liters. (I used to have a gallon milk jug that I used for watering plants that had a mark at the 0.1 Hubble-barn level. Very convenient.) My notes are scribbled in the back of "Gravitation", which is at work, but memory says that a Hubble-barn is the volume of a straw that has an opening the size of the nucleus of silver and reaches to the edge of the universe. BTW, a barn is 10^{-24} cm^2 -- 1 fm^2 = 10 mb. -- J. A. Carr | "The New Frontier of which I jac@gw.scri.fsu.edu | speak is not a set of promises Florida State University B-186 | -- it is a set of challenges." Supercomputer Computations Research Institute | John F. Kennedy (15 July 60) ------------------------------ Date: 13 Aug 92 03:06:30 GMT From: Keith Allan Schneider Subject: Parsecs? Newsgroups: sci.space,sci.physics zowie@daedalus.stanford.edu (Craig "Powderkeg" DeForest) writes: >bcollins@utdallas.edu (Arlin B. Collins) writes: > (Brian Kemper) writes: > > (Richard Martin) writes: > > > Please forgive my ignorance, but what the heck is a parsec? > > I know a parsec is a unit of distance equal to roughly 3 light-years ... > One parsec equals 30.857x10**12 km, 206265 astronomical units, and > 3.2616 light-years. Hmmm... at the distance of one parsec, one astronomical unit subtends an angle of one arc second. keith ------------------------------ Date: 12 Aug 92 17:40:29 GMT From: Ron Echeverri Subject: Parsecs? Newsgroups: sci.space,sci.physics In article <1992Aug13.030630.3919@cco.caltech.edu> keith@cco.caltech.edu (Keith Allan Schneider) writes: >Hmmm... at the distance of one parsec, one astronomical unit subtends an >angle of one arc second. Coincidence. Remember, one AU is the distance from the Earth to the Sun... 5150 look ma, i can nitpick too! :) ------------------------------ Date: 12 Aug 92 19:07:48 GMT From: "C.E. Johnson " Subject: Request: Sex in Space Newsgroups: sci.space There was an article posted a few years ago dealing with experiments on sex in space. If anyone has a copy of this, please forward it to my address. -- Carl E. Johnson 'Tis not the drinking that is Rochester Institute of Technology to be blamed, but the excess. carl@nick.csh.rit.edu - John Selden ------------------------------ Date: 13 Aug 92 02:28:44 GMT From: Robert W Murphree Subject: Solar System Journal Newsgroups: sci.space ADDENDUM GIOCOBBI-ZINNER memorable pictures: none, only particles and fields experiments This was one of the few examples of piracy by one member of the space community by another that I can recall. The spacecraft was launched as a solar wind monitoring craft and was never designed for comet encounters. When NASA decided to reassign it to comet encounter duty, it was over protests by some team members who lost their experiments. It really appears that number one) 1) NASA had realized they were going to lose international prestige by not joining the international flotilla of Halley encounter spacecraft (Europe, Soviets, and Japanese). What to DO? 2) send one of their own craft to make a first encounter with a comet, albeit, a one very poorly designed for such an encounter, and claim a PR victory by making their encounter before the Halley flotilla arrived at Halley. hence the Giocobbi-Zinner encounter. The other example of space piracy? A perfectly healthy working earth orbiting satellite that was shot down to test and probably also give PR boosts to SDIO, 4-5 years ago. You can bet the scientific investigators were mad about that one as well. ------------------------------ Date: 13 Aug 92 04:34:09 GMT From: Henry Spencer Subject: Solar System Journal Newsgroups: sci.space In article <1992Aug13.022844.9782@constellation.ecn.uoknor.edu> rwmurphr@uokmax.ecn.uoknor.edu (Robert W Murphree) writes: > 2) send one of their own craft to make a first encounter >with a comet, albeit, a one very poorly designed for such an >encounter, and claim a PR victory ... Actually, ISEE-3 was a fields-and-particles monitoring satellite, and not that ill-suited to a comet encounter. A custom-designed bird would have been a lot better, of course... but note that Giotto, custom-built for the job, is likewise mostly fields-and-particles experiments. >The other example of space piracy? A perfectly healthy >working earth orbiting satellite that was shot down to >test and probably also give PR boosts to SDIO... A perfectly healthy working satellite *built and owned by the Defense Department* that the legitimate owner decided to sacrifice to an antisatellite test (run by the USAF, not SDIO -- SDIO doesn't do antisatellite weapons, although they doubtless were keenly interested in the test). Yes, there were scientific experiments aboard, still yielding useful data, whose investigators were miffed about it. But there was no question of "piracy"; the satellite's owners merely decided that it had served its primary purpose and was expendable in what they saw as a worthy cause. This may have been a poor decision, but it *was* theirs to make. -- There is nothing wrong with making | Henry Spencer @ U of Toronto Zoology mistakes, but... make *new* ones. -D.Sim| henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 12 Aug 92 20:49:39 GMT From: Nick Szabo Subject: SPS feasibility (WAS: SPS fouling astronomy) Newsgroups: sci.space In article <10AUG199219061012@judy.uh.edu> seds%cspara.decnet@Fedex.Msfc.Nasa.Gov writes: >The cost is covered during a general buildup of lunar resource development >Reference the Lunar materials development papers of the last few years for >numbers. A very up to date set is from the ASCE Space 92 conference June 1-5 >1992 in Denver CO. Look Especially for Dr. Criswell's papers on the subject. Dr. Criswell makes his numbers up out of the thin blue air, especially the mass ratios for his fictional industrial processes. In many cases he assumes several orders of magntitude improvement over current industrial processes, and ignores large industrial inputs like air and water, without explanation. He is an utter fraud, and his fantasy (it's not even good science fiction) is highly destructive to the space colonization movement. >No but converting a transportation infrastructure that runs on billions of >gallons on Hydrocarbons per year to one of running on Terawatts of electricity >will require a vast increase in electrical production. You don't need to convince us about this. You need to convince the baby boomers running the electrical utilities that it takes more than "conservation" to power the world. >This is a flame and meant to be a flame. No, Fred's article was meant to introduce some reality into your thick-headed but narrow-minded skull. _This_ is a flame. >The Rio summit endorsed only ONE space technology and that was laser >power beaming from the moon. Which part of the "Rio summit"?. BTW, they also endorsed environmental monitoring from space, $100's of billions of give aways from the U.S. to 3rd world countries, and "sustainable development", for what it's worth. No major corporations and no politician beyond Al Gore take Rio seriously. Nobody with influence in industry takes Criswell seriously. >The SPS will help those who want to be helped. Pointing out the facts about SPS will help those who want to know the truth, and find out the best way to do things, but it won't do much for idiots who treat technology like religion. Your arguments sound far more like a Medieval bishop fighting heresy than a scientist searching for the truth or an engineer for the best solution. -- szabo@techbook.COM Public Access User --- Not affiliated with TECHbooks Public Access UNIX and Internet at (503) 644-8135 (1200/2400, N81) ------------------------------ End of Space Digest Volume 15 : Issue 105 ------------------------------