Date: Mon, 7 Dec 92 05:03:56 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #517 To: Space Digest Readers Precedence: bulk Space Digest Mon, 7 Dec 92 Volume 15 : Issue 517 Today's Topics: absolutely, positively overnight anniversary cancelled Apollos Detonavion vs Deflagration (was Re: Shuttle replacement) Japanese Solar Mission_Yokoh:comparisons? Lunar flight (3 msgs) Orbit Question? Pioneer and Voyager messages Satellite orbits Shuttle replacement Spherical Space stations Voyager's "message"... What did it *say*?!? 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: Mon, 7 Dec 1992 03:24:47 GMT From: "Simon E. Booth" Subject: absolutely, positively overnight Newsgroups: sci.space In article henry@zoo.toronto.edu (Henry Spencer) writes: >In article <1992Dec03.163120.11057@eng.umd.edu> sysmgr@king.eng.umd.edu writes: >>>can't get a non-stop flight from John Wayne to Antarctica, so why would >>>anyone expect to get a non-stop flight from John Wayne to orbit? >> >>Depends. Some earlier speculation on using DC-1 for sub-orbital hops which >>would bring new meaning to the word "absolutely, positively overnight." > >Reportedly, if DC-1 can be built and suitably certified, Federal Express >is most definitely interested. >-- And if the airlines are interested, what about 30 minute transcontinental or trans-oceanic flights. :-) Simon ------------------------------ Date: 7 Dec 92 08:36:09 GMT From: Henry Spencer Subject: anniversary Newsgroups: sci.space Lest we forget... Twenty years ago today -- to be precise, at 0033 EST -- the last ship left for the Moon. -- "God willing... we shall return." | Henry Spencer @ U of Toronto Zoology -Gene Cernan, the Moon, Dec 1972 | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 7 Dec 92 08:02:26 GMT From: Henry Spencer Subject: cancelled Apollos Newsgroups: sci.space.shuttle,sci.space >> Do you mean that the Apollo 18 mission was targeted for Hadley, not 15? ... > >I don't remember the targeting assignments, but the crucial fact here is >that there were two flavors of Apollo missions involved... More Apollo archeology... Site selection had settled down by early 1970, with minor ongoing revision. The cancellation of Apollo 20 had more or less coincided with a decision that a landing in Tycho crater was too difficult, and that had been the primary target for Apollo 20, so that one was easy (although regrettable because Tycho was of great geological interest). There was also some reshuffling of missions then, because the Marius Hills mission required instrument development that might not be done in time for its Apollo 16 slot, and also the site was reachable within the mission rules only in summer. So the list then was 13 Fra Mauro 14 Littrow 15 Censorinus 16 Copernicus 17 Descartes 18 Marius Hills 19 Hadley Apollo 13 was meant to visit Fra Mauro, because the Fra Mauro Formation was thought to consist of material excavated by the impact that formed Mare Imbrium -- a major event in lunar history, dating of which was important, and also one that probably excavated material from deep down. The Apollo site-selection board decided, in the wake of the Apollo 13 failure, that Fra Mauro was still first priority, so Apollo 14 went there instead of Littrow. They also recommended moving 15 to a site near Davy crater, assuming Apollo 14 could get adequate photos. Not only did the 14 photos not come through in time, but by then, it was clear that more missions were going to die. After lengthy discussion and review of a number of sites, Littrow, Descartes, Hadley, and the Marius Hills were deemed to be both feasible (both Copernicus and Censorinus were now off the list due to excessively rough terrain) and scientifically significant. For Apollo 15, it was thought desirable to have a high probability of major advances in lunar science, adequate photography without waiting for Apollo 14 results, mission feasibility without deep analysis, and a site suitable for either an H or J mission so that it could be flown regardless of which type 15 was (at the time it was still an H, but if missions were to be cancelled, cancelling the last H mission was an obvious possibility). This last was particularly significant because it meant picking a site that didn't need the J's lunar rover but would benefit if it were available. Hadley got high marks for providing access to several different geological features even without a rover, being on various disciplines' high-priority lists, and putting an ALSEP package at a high-latitude site (highly desirable to give three-dimensional coverage for the seismometers and retroreflectors, since most other sites were near the equator). When two more Apollos, including the last H mission, were canned, Hadley and Marius Hills fought it out for Apollo 15. Hadley won by a nose: the two sites were very evenly matched until David Scott, picked to command the mission, said he preferred landing at Hadley. The board picked Hadley for 15, pencilled in Descartes for 16, and left 17 open with several possibilities being debated. Site selection for 16 ended up debating Descartes vs. Alphonsus. Both looked like good places for highlands material and volcanic material. Descartes got the nod mostly because it was thought preferable to have the 14 and 15 results fully in hand before committing to a landing at Alphonsus; Alphonsus was left as a candidate for 17. In the end, it turned out that the Descartes site was not volcanic at all, which caused a lot of re-evaluation of the site-selection photogeology, because it had sure looked like it. Confusion about the Moon's geological history was getting worse, not better, with more Apollo results. Site selection for 17 looked like it might produce a full-scale war, so it got started early, well before 16 flew. However, in the end it wasn't that bad, because the fact that it was the last chance for many years produced strong consensus on objectives: pre-Imbrium highlands as far from Mare Imbrium as possible, "young" volcanic rocks, coverage from orbit of areas not previously seen up close, and best coverage for some new geophysics instruments. Three sites made the short list: Taurus-Littrow, Gassendi, and (a distant third) Alphonsus. T-L got top marks on most everything with the bonus of a reasonable walking mission if the rover failed. T-L had one problem: in worst-case conditions, Apollo's nominal-landing-area ellipse would not fit the suitable terrain. Gassendi also had operational problems, though, since a slightly off-target landing might make major objectives entirely unreachable. The trajectory people were encouraged to reconsider the T-L calculations based on 15's precision landing; the results cleared T-L and it was picked. Most of the above is from NASA SP-4214, "Where No Man Has Gone Before", which is the NASA History volume covering Apollo lunar exploration proper (as opposed to hardware development). >I don't remember exactly which CSMs got used for Skylab. 116 (the fifth J CSM) flew the first crew, 117 the second, and 118 the third. 111 (the last H) was Apollo-Soyuz. 119 (the last[?] J) was allocated as Skylab rescue if necessary, then shifted to Apollo- Soyuz backup. Where 115 went I'm not sure. -- 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: Mon, 7 Dec 1992 08:10:53 GMT From: Henry Spencer Subject: Detonavion vs Deflagration (was Re: Shuttle replacement) Newsgroups: sci.space In article <1992Dec7.032126.7834@ringer.cs.utsa.edu> sbooth@lonestar.utsa.edu (Simon E. Booth) writes: >I don't know if this is correct, but an article that came out in a local >paper on 29 January 1986 that said that the Challenger ET exploded with a >force of 1.7-2 megatons... This would be difficult, since there isn't anything like that much fuel on board. (LH2/LOX is more powerful than TNT, but not by that much.) I think somebody confused megatons with kilotons. Worst-case explosions for both Saturn V and shuttle are in the 1-2 kiloton range. However, the Challenger ET did not explode. At all. It suffered major structural failures and spilled its contents, which burned rather quickly. No explosion. The orbiter was destroyed by being thrown violently out of control at Mach 3, which caused massive structural failure. -- 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: 7 Dec 92 03:34:48 GMT From: Ed Schmahl Subject: Japanese Solar Mission_Yokoh:comparisons? Newsgroups: sci.astro,sci.space,sci.physics The Yohkoh satellite is a very well implemented solar satellite with a lot of improvements over Solar Max. The SXT (soft X-ray telescope) can map the X-ray Sun with 5 arcsec resolution in less than a minute, and can zero-in to a smaller field for higher time resolution of flare events. It also has an X-ray spectrometer with higher energy sensitivity One of its most powerful instruments, however, is the HXT (Hard X-ray telescope), which can image solar flares at energies up to 50 keV, with spatial resolution as good as 8 arcsec. The satellite has been in orbit for a little over a year now, and its results are revolutionizing our understanding of solar flares and coronal mass-ejection events. Ed Schmahl Astronomy Dept. University of Maryland -- Edward J. Schmahl | Internet: ed@astro.umd.edu (128.8.251.56) Lab for Astr & Solar Phys| Gateway: eschmahl@solar.stanford.edu Goddard Space Flt. Ctr. | SPAN: CHAMP::SCHMAHL (128.183.10.108) Greenbelt, MD 20771 | Voice: (301) 286-5114 ------------------------------ Date: Mon, 7 Dec 1992 06:03:31 GMT From: "Simon E. Booth" Subject: lunar flight Newsgroups: sci.space In article roberts@cmr.ncsl.nist.gov (John Roberts) writes: > >-From: henry@zoo.toronto.edu (Henry Spencer) >-Subject: Re: Lunar flight >-Date: 6 Dec 92 01:49:57 GMT >-Organization: U of Toronto Zoology > >-Except that Clinton & Co have already came out as opposed to any resumption >-of manned space exploration, or any preliminary steps towards it, no matter >-how cheap. > >Wrong. > I second that. I truly hope our space program can survive the Clinton administration. Based on info I read during the campaign VP-elect Gore is very pro technology. While I didn't vote for Clinton/Gore, I won't write off our space program yet. Simon ------------------------------ Date: Mon, 7 Dec 1992 05:45:22 GMT From: "Simon E. Booth" Subject: Lunar flight Newsgroups: sci.space On the subject of lunar flight, would a DC-type spacecraft be capable of a lunar landing mission? Theoretically, extra supplies could be carried in place of cargo, but I'm not sure whether or not the normal crew accomodations would be suitable for a flight lasting more than a few days, plus time on the lunar surface. I haven't seen any info on the DC-series outside of the net, so I do apologize if my "theories" are inaccurate. I'm not a scietist, just a space enthusiasti. :-) Simon ------------------------------ Date: Mon, 7 Dec 1992 08:14:10 GMT From: Henry Spencer Subject: Lunar flight Newsgroups: sci.space In article <1992Dec7.054522.10124@ringer.cs.utsa.edu> sbooth@lonestar.utsa.edu (Simon E. Booth) writes: >On the subject of lunar flight, would a DC-type spacecraft be capable of >a lunar landing mission? Theoretically, extra supplies could be carried >in place of cargo, but I'm not sure whether or not the normal crew >accomodations would be suitable for a flight lasting more than a few >days, plus time on the lunar surface. Life support and such would probably need some souping up. Propulsion is up to the job, if refuelled in Earth orbit. Landing and takeoff might need some work, possibly including revised landing gear. Earth reentry would need careful design. In short: possible in principle, work needed on details. -- 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: Mon, 7 Dec 1992 06:13:58 GMT From: "Simon E. Booth" Subject: Orbit Question? Newsgroups: sci.space In article prb@access.digex.com (Pat) writes: >In article <1992Dec5.222622.758@ualr.edu> hdgarner@acs.harding.edu writes: >>I have a question concerning geosyncrenous (please excuse my spelling, my >>dictionary was printed before space exploration got started) orbits. It is >>my understanding that a body in geosyncronous orbit remains over the same >>point on the earth and has the same rotational period as the Earth. My >>question is what happens to a body that is in geosyncronous orbit at either >>the north or south pole. Does it remain stationary above the pole? >>If you can help me with this question please mail me. >>Thanks. >> >>hdgarner@harding.edu > > >Geo sync orbits only exist at 0 latitude. you could put a relay >at 90 degrees, but youd need a huge amount of fuel to hover there. > >To do ppolar communications, either LEO relays sats are used >or you can create highly inclined highly elliptical orbits that >leave the bird hovering for a few hours at perigee, a modest tracking >antenna can then follow the bird. if you have several in the constellation, you can have continous coverage. > This is what the Soviets did with many of their communications satelites to hover their northern regions. I read that the orbits were highly inclined, 300 by 25,000 miles or something like that. ------------------------------ Date: 7 Dec 92 04:48:29 GMT From: "Simon E. Booth" Subject: Pioneer and Voyager messages Newsgroups: sci.space In article HAIRSTON%UTDSSA.DECNET@relay.the.net writes: > For folks interested in trying to deciper the Pioneer plaques and the >Voyager records, check your library or used book store for "Murmurs of >Earth" by Carl Sagan et al. Essentially it's a first-hand account of the >designing of these messages, plus the bureaucratic hassles they went through >to get them onto the spacecraft. **Ad Astra Per Bureaucracia** > > On a related note, Dave Barry once pointed out in a column (since reprinted >in his book "Bad Habits") that the most likely lifeform to ever find these >messages would be the interstellar equivalent of some back-country highway >patrol officers. He envisions one of them saying: "Looks like what we have >here is a hydrogen-sniffin' perverted species who force their women to run >around nekkid and probably say 'billions' a lot. Whadda say we go wipe 'em >out and then ooze over to the diner for some lunch?" > I read somewhere that if anyone finds the Pioneer and Voyager probes, they will probably be interstellar travelers from earth at some point in the distant future. But would they still be able to understand the languages on the disks? ------------------------------ Date: 7 Dec 92 19:05:31 GMT From: Jarno Linden Subject: Satellite orbits Newsgroups: sci.space Ok, I know the format of the 2 line orbital element sets which are regularly posted in sci.space.news. What I now need are some formulae to translate these figures into a long/lat coordinate or an (x,y,z) coordinate for a satellite at time t. Preferbly something I can stick into some code. Note: I am NOT asking for complete program listings, I don't want my E-Mail costs to go through the roof (and as yet no FTP access). |#|=AmigaShell==========================================================|#|#| |1> echo >NIL: Jarno_Linden@kcbbs.gen.nz _ // This message has | | |1> echo >NIL: IFNA 3:772/90 Jarno Linden \X/ temporarily seized to exist |_| |_________________________________________________________________________|/| ------------------------------ Date: Mon, 7 Dec 1992 05:25:29 GMT From: "Simon E. Booth" Subject: Shuttle replacement Newsgroups: sci.space In article <1992Dec5.211444.22824@cs.rochester.edu> dietz@cs.rochester.edu (Paul Dietz) writes: >In article <1992Dec5.160433.17868@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes: > >> How many people does it take to operate the liquid hydrogen and liquid >> oxygen plant? You've got to have one everywhere DC takes off. > >Well, no. Liquid oxygen and hydrogen can be delivered by truck or >rail car. Haven't you ever driven behind a liquid hydrogen tanker >truck on the interstate? And LOX is delivered by tanker to hospitals, >universities and industry all the time. > >You may want a holding tank, but that's much less complex than >a separation plant. > How much of a problem would boil-off be during transportation and storage of cryogenic fuels?? Simon ------------------------------ Date: 6 Dec 92 06:35:03 GMT From: James Thomas Green Subject: Spherical Space stations Newsgroups: sci.space In article 18084TM@msu.edu (Tom) writes: > > >Wouldn't spheres have the (dis)advantage of no tidally preferred direction? >Meaning, depending on your preference, that it could rotate to any orientation >preferred, or that station-keeping would be more difficult? > This could be fixed by using one or two teathered counterweights (which could be useful payloads themselves). One could be "upward" and the other oriented "downward". The gravity gradient would pull them tight and give the craft a certain orientation relative to the Earth. This concept was proven on one of the Gemini Flights when the G was teatherer to an Agena it had met in orbit. To a lesser extent this was also shown on the recently failed (and hopefully soon to be reflown) Shuttle teather experiment. /~~~(-: James T. Green :-)~~~~(-: jgreen@eros.calpoly.edu :-)~~~\ | | | Slogans of two generations: 1972: Question Authority! | | 1992: Why Ask Why? | ------------------------------ Date: Mon, 7 Dec 1992 05:08:30 GMT From: vincent seifert Subject: Voyager's "message"... What did it *say*?!? Newsgroups: sci.astro,sci.space In article henry@zoo.toronto.edu (Henry Spencer) writes: >In article <1992Dec6.104628.13150@ringer.cs.utsa.edu> sbooth@lonestar.utsa.edu (Simon E. Booth) writes: >>Pardon the odd question, but is there a recording of the "Voyager Record" >>available? > >It's just recently come out on CD, although it's expensive ($80 or so). > >>I've always been interested in exactly what was recorded on it. > >In that case, you probably want the book "Murmurs of Earth" rather than >the CD. Warner New Media #14022, "Murmurs of Earth: the Voyager Interstellar Record", contains the Sagan "Murmurs of Earth" book and a two-CD set of the Voyager record; one CD has a data track on it containing the images, displayable with a 286-or-better SVGA PC clone or a Mac II or LC. Both CDs have the how-to-play-this diagrams from the outside of the Voyager record package on them, which is cute. :) List price is $79.95, but I got mine for $49.99 at Egghead. The CDs themselves have another number on them, WNM 14021, so you may be able to get them separately. I like mine. If you watched "Cosmos", some of the music may be familiar. Vince Seifert Equipment Tech III seifertv@csus.edu CSUS hired me to fix their computers, not to air their policies. -- Vince Seifert Equipment Tech III seifertv@csus.edu CSUS hired me to fix their computers, not to air their policies. ------------------------------ End of Space Digest Volume 15 : Issue 517 ------------------------------