Date: Sun, 30 Aug 92 04:59:57 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #151 To: Space Digest Readers Precedence: bulk Space Digest Sun, 30 Aug 92 Volume 15 : Issue 151 Today's Topics: "For All Mankind" Apollo Video Clips Ground support for LDO shuttle as ACRV Inflationary universe Is Galileo's antenna still brok? LDO shuttle and pilot readiness Magnetic Sail (2 msgs) Mars Pictures request Size,Mass,and velocity.... (2 msgs) Sizing of launch vehicles (was Saturn Class) (2 msgs) Soviet rovers on Mars TOPEX, demise of SEASAT & nuclear sub wakes TOPEX, SEASAT & nuclear sub ``wakes'' Venus orbiters 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: Sat, 29 Aug 92 21:09:33 -0500 From: pgf@srl03.cacs.usl.edu (Phil G. Fraering) Subject: "For All Mankind" \Incidentally, if anyone knows where the video of this can be found, I'd /love to know. I saw it two(?) years ago when it was in theatrical \release and I thought it was way boffo cool. Yes. It can be found on the shelf about 10 feet from where I am sitting. Seriously, folks, I would like to get some discussion on these things started, with some comments from me Monday when I can really post. L8r.......... I mean, discussion on _For All Mankind_... -- Phil Fraering pgf@srl0x.cacs.usl.edu where the x is a number from 1-5. Phone: 318/365-5418 SnailMail: 2408 Blue Haven Dr., New Iberia, La. 70560 If seven maids with seven brooms swept it for half a year, do you think, the Walrus asked, that they could make it clear? I doubt it, said the Carpenter, and shed a bitter tear. ------------------------------ Date: 28 Aug 92 18:50:40 GMT From: Bruce Watson Subject: Apollo Video Clips Newsgroups: sci.space In article <1992Aug27.181710.26123@news.acns.nwu.edu| fred@iapetus.earth.nwu.edu (Fred Marton) writes: |In article <27AUG199211290242@lims02.lerc.nasa.gov+ afwendy@lims02.lerc.nasa.gov (WENDY WARTNICK) writes: |+>In article <17h3qoINNloo@grapevine.EBay.Sun.COM> wag@georwell.EBay.Sun.COM writes: |+>>The famous feather and hammer trick is on the PBS special "For All Mankind". |+> |+ |+pardon my ignorance...what ARE we talking about? |+ |+ wendy | |"For All Mankind" is a documentary on the Apollo program. It's unique in that |all the images and words are from NASA, i.e., astronaut-shot footage and |their reactions, explanations, etc.. It also has a score by Brian Eno |(if memory serves). I think Wendy may be asking about the "feather and hammer trick". It was a demonstration by one of the Apollo astronauts on the moon that showed in a vacuum these two objects hit the lunar surface at the same time. -- Bruce Watson (wats@scicom) Tumbra, Zorkovick; Sparkula zoom krackadomando. ------------------------------ Date: Sat, 29 Aug 1992 16:22:20 GMT From: GRASSO CHRISTOPHER A Subject: Ground support for LDO shuttle as ACRV Newsgroups: sci.space Several times during the discussion on station resupply and crew return, the notion of using one of the long-duration orbiters as the crew rotation and ACRV has been mentioned. While one shuttle is docked at Freedom, others would presumably fly indpendent missions. My question: what changes to mission ops will be necessary to provide ground support for the two vehicles simultaneously? Presumably, since an LDO is specified, the docked shuttle will not draw power and control signals from Freedom, but will be an independently operating vehicle with its own systems "on" and requiring oversight. Or is some sort of data adapter planned to hook Freedom data and control paths to shuttle flight control systems? Or is the flight telemetry to be relayed to Freedom to allow the astronauts on station to control shuttle systems in a manner similar to ground controllers? -Chris -- Chris Grasso CSC Univ. of Colorado, Boulder ------------------------------ Date: 29 Aug 92 11:51:50 GMT From: Ahmed Abd-Allah Subject: Inflationary universe Newsgroups: sci.astro,sci.space,sci.physics I recently posted a question regarding the shape of the universe, and I'd like to thank those who replied. My original question was: >If in a closed universe, we could travel in a "straight" line and >end up back where we started, and in an open universe we couldn't... >then what happens in a flat universe? I'm not sure if I understood >the physics correctly, but is it accurate to say that the inflationary >universe scenario starts out with Omega less than 1 (so the universe >is closed), then as it "inflates", Omega rapidly approaches 1 so >that expansion forever continues BUT the universe remains closed?? From my own further reading, and from most of the replies I got, Omega is either EXACTLY one in inflation theory or stupendously close, and getting closer by the day. Most of the replies I got stated that in a flat universe, one could never travel in a 'straight' line ('geodesic') and end up at the startinmg point because the flat case means an infinite universe eventually. However one replier pointed out that I may be confusing open/flat/closed with (finite but unbounded)/infinite. To make a long story short: where is the following thought experiment wrong? If the universe started out as a finite ball that got bigger and bigger, then that means that today it is just a bigger ball, right? If Omega is one, then this means that the expansion is slowly approaching zero, I believe - but never quite reaching it. Does this mean that, if we were 'immortal', we could head out in some space travel vehicle which chugs along at some constant speed which would EVENTUALLY be greater than the speed of expansion - so in a flat universe we WOULD end up back where we started? Just that if we tried to repeat the same journey, it would be different? I guess I am having trouble understanding why having a forever expanding finite universe means that it is infinitely large TODAY. It can't be right? At any point in time, a flat universe will be finite in size. ************************* Yes, it does sound ignorant ;-) but I'm no cosmologist... Please EMAIL your replies to aabdalla@pollux.usc.edu Thanks Ahmed ------------------------------ Date: 29 Aug 92 14:29:44 GMT From: Josh 'K' Hopkins Subject: Is Galileo's antenna still brok? Newsgroups: sci.space evert@CPSnet2.cps.edu (Mike Evert) writes: >How's that antenna doing? The last few Galileo updates that I've seen >posted here had nothing to say on the subject. Did they fix it or >give up on it? Is there hope? The High Gain Antenna is still not functional. Someone from JPL told me recently that they have discovered that if they turn on the motor very briefly, it will advance a tiny amount, but not slip back. He said that they plan to try this up to a hundred times and hopefully will be able to get the screw to advance at least a full revolution. He was optimistic, but "we won't know until we try." It should be noted that thanks to compression techniques, JPL expects to do 75% of the science they had planned even if the HGA never opens, including receiving 100% of the data from the atmospheric probe. -- Josh Hopkins Friends don't let friends derive drunk j-hopkins@uiuc.edu ------------------------------ Date: Sat, 29 Aug 1992 16:29:20 GMT From: GRASSO CHRISTOPHER A Subject: LDO shuttle and pilot readiness Newsgroups: sci.space After being on orbit for 2 months, how realistic is it for a shuttle pilot to be capable of performing a reentry and landing? Seating in the shuttle is upright, airliner-style, while seating in a capsule is reclined to horizontal. If the extended stay in microgravity damages the shuttle pilots' ability to bring the spacecraft back for a landing, doesn't this mandate a separate ACRV if shuttle is to be used for resupply and crew rotation? -Chris -- Chris Grasso CSC Univ. of Colorado, Boulder ------------------------------ Date: Sat, 29 Aug 1992 10:11:35 GMT From: Paul Dietz Subject: Magnetic Sail Newsgroups: sci.space In article ep1a+@andrew.cmu.edu (Eric Eimal Paulsen) writes: > Maybe you've already heard of this, but I just read an article in the > May or July '92 Asimov Sci-Fi magazine about a magnetic sail idea. It > started from a ram scoop and was turned into a superconduction loop held > from the center by lines. It works on the premise of skipping around in > LEO by working against the Earths magnetic field until it gets into the > solar wind and can deflect it, gaining something like .02 g, much better > than Ion Drive. Really good for interplanetary travel. Possible > application as brake in interstellar flight, eliminating half of fuel > load. The article (about ten pages long) has a lot of mathmatics to back > it up, way over my head. Fascinating implications! Unfortunately, I get the impression they badly miscalculated the tension on the loop, which renders the whole idea much less interesting, as the loop would have to be much more massive. (It was Analog, not IASFM.) Paul F. Dietz dietz@cs.rochester.edu Great moments in humanitarianism: "How can we help a foreign country to escape overpopulation? Clearly the worst thing we can do is send food . . . . Atomic bombs would be kinder. For a few moments the misery would be acute, but it would soon come to an end for most of the people, leaving a few survivors to suffer thereafter." Garrett Hardin, 1969. ------------------------------ Date: 29 Aug 1992 16:46:13 GMT From: Frank Crary Subject: Magnetic Sail Newsgroups: sci.space In article <1992Aug29.101135.16007@cs.rochester.edu> dietz@cs.rochester.edu (Paul Dietz) writes: >Unfortunately, I get the impression they badly miscalculated the >tension on the loop, which renders the whole idea much less interesting, >as the loop would have to be much more massive. Actually, he didn't calculate the loop tension at all. (At least not in the pre-print of the technical paper I have. He caluclated a mass based on the critical current density and mass density of the superconductor, and the loop current: M = 2pi*RAp = 2pi*RIp/J Where R is the sail radius, A is the cross sectional area of the loop, p is the mass density of the material, I is the maximum loop current and J is the critial current density of the superconductor. Zubrin seems to simply assume the tension on the loop will be low. A more serious problem is his use of high temperaature superconductors: He assumes nitrogen-temereature superconductors with properties like those of helium-temereature ones. We don't have anything like that at the moment, and the people working in the field have been promising them "soon" since high temperature superconductors were first dicsovered 6 years ago. Frank Crary CU Boulder (By the way, does anyone know how to get a usenet feed here at Boulder? My new account is on pprince, which doesn't seem to accept news commands. Remote logins to my old Berkeley account are getting to be a pain...) ------------------------------ Date: 30 Aug 92 06:13:00 GMT From: Dave Beaujean Subject: Mars Pictures request Newsgroups: sci.space Hi All! I am looking for picture of Mars which would let me become familiar with Mars before the mapping project gets going. I am especially interested in the "Face on Mars" area which I have only heard mentioned before. I know there are bazillions of gifs on ames and spacelink, but I was wondering if there is a specific area where these type of pictures may be located at. Any help would really be appreciated!!! Dave (New father of a future space traveler!!!) ------------------------------ Date: 28 Aug 92 17:30:02 GMT From: Steve Ispas Subject: Size,Mass,and velocity.... Newsgroups: sci.space I think Tom Nugent is right when he writes: Flame on!} I don't mean to flame, but this seems to be a big waste of bandwidth. You can find things like this just about anywhere. Surely in an encyclopedia, if not a good dictionary. Call up your local library (you don't even have to leave home) and they may be willing to give it to you over the phone. Otherwise, go to the library, and look it up along with ten zillion other neat things about space you can find there. {Flame off!} The idea is not that he is a spoilsport. The idea is that he is helping by pointing out the library, which is an excellent source of information rather than putting it on the network. It's not a matter of wasting bandwidth, but if someone is interested in that kind of statistical information he/she would find so much in a library, or encyclopedia. ****************************************************************************** * Steve Ispas +-----+ * * LSI Logic Corporation Phone : (408) 433-8799 LSI LOGIC * 1501 McCarthy Blvd. FAX : (408) 433-6802 | | * * M/S E-192 email : sispas@qafs2 +-----+ * * Milpitas, Ca. 95035 internet : sispas@lsil.com * ****************************************************************************** ------------------------------ Date: 29 Aug 92 23:38:29 GMT From: "Frederick A. Ringwald" Subject: Size,Mass,and velocity.... Newsgroups: sci.space In article <1992Aug28.173002.19958@lsil.com> sispas@lsil.com (Steve Ispas) writes: > I don't mean to flame, but this seems to be a big waste of bandwidth. You > can find things like this just about anywhere. Grrr. If you're really so concerned about the extra bandwidth, why keep posting about it? I feel an duty to education in my field. True, I was not about to type in all those numbers myself, but did I e-mail the original poster some references to look up in the library. Anyone who asks so clueless a question should be helped out! That's ALL, folks, Fred ------------------------------ Date: 28 Aug 92 14:26:19 GMT From: eder@hsvaic.boeing.com Subject: Sizing of launch vehicles (was Saturn Class) Newsgroups: sci.space jbh55289@uxa.cso.uiuc.edu (Josh 'K' Hopkins) writes: >Allen said... >is), how do you plan to use an HLV? The baseline plans I've seen put Ariane 5 >at about the right size, and if you increase the payload, you decrease the >number of flights to the point where I begin to wonder if it's commercially >viable. Maybe we need to agree on a definition of Heavy Lift. Okay, time for a lesson in the economics of launch vehicles: The Air Force performed a study in 1989 for the Secretary of Defense on launch systems for SDI. The study was executed by the Space Systems Division of the AF Systems Command. These are the folks who procure rockets for the AF. In the study they surveyed all existing and proposed domestic launchers, and evaluated their costs at different flight rates. I plotted the data at high flight rates and found that the cost per kilogram ran as $8,000 x (mass in tons)^-0.3. Thus, as the launch vehicle got larger, the cost per kilogram goes down, approximately dropping by half for each factor of ten in payload increase. Now, this is purely recurring costs, and does not include development. In 1986 I was the cost engineer for an earlier space transportation study, funded jointly by NASA and the AF. We found that for a clean sheet expendable rocket, the development cost ran ( in today's dollars) as $1.5 million x (liftoff weight)^0.553. In other words, the development cost ran roughly as the square root of size. The payload relationship ran Payload wt = -10,427lb + (0.0436 x Gross liftoff weight). So, for particular sizes we have: Payload (lb) Liftoff weight (lb) Development cost ($) 10,000 468,500 $2.05 billion 20,000 697,900 $2.55 billion 30,000 927,200 $2.99 billion 40,000 1,156,600 $3.38 billion 50,000 1,386,000 $3.74 billion Now, for the space station delivery job alone, you have a need to deliver 75 tons per year (5 Shuttle loads), for say 10 years. Thus you have a total delivery requirement of 750 tons, or 750,000 kg. To find total cost, we need to add recurring and development costs, with the development cost spread over the launched mass: Payload (kg) Launch $/kg Develop $/kg Total $/kg 4,536 5,082 2,733 7,816 9,072 4,128 3,400 7,528 13,608 3,655 3,987 7,642 18,144 3,353 4,506 7,860 22,680 3,136 4,987 8,122 So, considering the Space Station delivery job only, the optimum size seems to be around 10 tons payload. Now, if you consider other launch jobs that exist, and look at longer time horizons, you tend to get larger vehicles as the optimum, but you are a long way from HLLV numbers unless you have massive traffic requirements. Dani Eder -- Dani Eder/Boeing/Advanced Civil Space/(205)464-2697(w)/232-7467(h)/ Rt.1, Box 188-2, Athens AL 35611/Member: Space Studies Institute Physical Location: 34deg 37' N 86deg 43' W +100m alt. ***THE ABOVE IS NOT THE OPINION OF THE BOEING COMPANY OR ITS MANAGEMENT.*** ------------------------------ Date: 29 Aug 92 23:47:04 GMT From: Frank Crary Subject: Sizing of launch vehicles (was Saturn Class) Newsgroups: sci.space In article <1579@hsvaic.boeing.com> eder@hsvaic.boeing.com (Dani Eder) writes: >Now, for the space station delivery job alone, you have a need to >deliver 75 tons per year (5 Shuttle loads), for say 10 years. Thus >you have a total delivery requirement of 750 tons, or 750,000 kg. >To find total cost, we need to add recurring and development costs, >with the development cost spread over the launched mass: >[Numbers based on his launch/development cost model.] >So, considering the Space Station delivery job only, the optimum >size seems to be around 10 tons payload. This neglects the use of pre-existing systems (e.g. ones where the development costs have already been paid for.) But more importantly, you are treating the Space Station as a constant-mass payload, which need only be delivered to orbit. Assembling the pieces will also be required, and clearly assembly of 75 10-tonne pieces is much harder than assembly of (say) 15 50-tonne pieces. I suspect the difference in costs (which was only around a 10% difference between 10 and 25 tonne payloads) would be overshadowed by the changes in on orbit assembly costs. Frank Crary CU Boulder (By the way, does anyone know how to get usenet access here at Boulder? My new account is on a machine that doesn't seem to connect, and remote logins to my old Berkeley account are getting to be a pain...) ------------------------------ Date: 29 Aug 92 14:19:27 GMT From: Josh 'K' Hopkins Subject: Soviet rovers on Mars Newsgroups: sci.space JDAVIS@GRIFFIN.UGA.EDU (Jerry Davis) writes: >>From: Bill Higgins-- Beam Jockey >>(I'm not familiar with their instrument load). Phobos 2 and one of the >>Soviet Mars landers carried tiny rovers, too. Or do we only count >>spacecraft that succeeded? ^^^^ > ? >Tiny? I'm not sure about Phobos 2, but 2 weeks ago I saw a Soviet Mars >rover at the Air Force Museum, Wright Patterson AFB and it was pretty >big. The rover you saw was almost certainly a design for the upcoming Mars '94 mission. It is, indeed, large, and in fact there has been discussion of putting one or two tiny American rovers on to piggy back around Mars and get off and check things out when it's too dangerous for the larger rover to go. Bill, did Phobos 2 have a surface lander or are you refering to the little hopping thing that was supposed to land on Phobos? -- Josh Hopkins Friends don't let friends derive drunk j-hopkins@uiuc.edu ------------------------------ Date: 29 Aug 92 13:36:59 GMT From: Gerald Cecil Subject: TOPEX, demise of SEASAT & nuclear sub wakes Newsgroups: sci.space How do the altimeter & SAR resolutions on TOPEX compare with those that were on SEASAT? I recall comments at the time of the premature demise of SEASAT that it had detected ``wakes'' from submerged USN nuclear subs on patrol, and that more rabid elements had suggested that the DOD had pulled the plug (I think that the accepted explanation of its failure after only a few weeks was a chip burnout, remarkable that there was no redundancy.) Have sub props been modified? Does anyone have further details on the demise of SEASAT? -- Gerald Cecil cecil@wrath.physics.unc.edu 919-962-7169 Physics & Astronomy, U North Carolina, Chapel Hill, NC 27599-3255 USA If we don't succeed, we run the risk of failure. -- Chairman of US Space Council. ** Be terse: each line cost the Net $10 ** ------------------------------ Date: 29 Aug 92 13:30:26 GMT From: Gerald Cecil Subject: TOPEX, SEASAT & nuclear sub ``wakes'' Newsgroups: sci.space,sci.astro How do the altimeter & SAR resolutions on TOPEX compare with those that were on SEASAT? I recall comments at the time of the premature demise of SEASAT that it had detected ``wakes'' from submerged USN nuclear subs on patrol, and that more rabid elements had suggested that the DOD had pulled the plug (I think that the accepted explanation of its failure after only a few weeks was a chip burnout, remarkable that there was no redundancy.) Have sub props been modified? Does anyone have further details on the demise of SEASAT? -- Gerald Cecil cecil@wrath.physics.unc.edu 919-962-7169 Physics & Astronomy, U North Carolina, Chapel Hill, NC 27599-3255 USA If we don't succeed, we run the risk of failure. -- Chairman of US Space Council. ** Be terse: each line cost the Net $10 ** ------------------------------ Date: 29 Aug 92 05:37:00 GMT From: David Knapp Subject: Venus orbiters Newsgroups: sci.space In article <6wZ5PB7w164w@curlie.UUCP> thierry@curlie.UUCP (Thierry Lach ) writes: >baalke@kelvin.jpl.nasa.gov (Ron Baalke) writes: > >> In article , rabjab@golem.ucsd.edu (Jeff Bytof) w >> >Is the Pioneer Venus orbiter still functioning? >> >> Yup, but it is running out of propellent and is due to burn up in the >> atmosphere of Venus this December. >> >> >Besides Magellan, >> >what other spacecraft (Russian?) may be still functional? >> >> Here's a list of deep space spacecraft that are still operating. >> > >Will magellan be in any position to gather data from the burn-up? > Magellan doesn't *need* to be in any position to gather data from the burn-up. PVO will be transmitting until the bitter end. The thing that will cause the last data drop out is the 'breeze' blowing the PVO antenna off pointing to Earth. *Much* data will have been gotten by that point. -- David Knapp University of Colorado, Boulder Highly Opinionated, Aging and knapp@spot.colorado.edu Perpetual Student of Chemistry and Physics. Write me for an argument on your favorite subject. ------------------------------ End of Space Digest Volume 15 : Issue 151 ------------------------------