Date: Sat, 22 Aug 92 05:02:00 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #136 To: Space Digest Readers Precedence: bulk Space Digest Sat, 22 Aug 92 Volume 15 : Issue 136 Today's Topics: Apollo Video Clips Asteroid report (2 msgs) BuckyStalks (was Re: Beanstalks in Nevada Sky) Energya and Freedom and Soyuz ACRV and... Inflatable Space Stations - Why Not ? Opinions on NLS Private space ventures Tethers Viable alternatives to space? Was ( Re: Private Space Ventures) What happened to Viking? With telepresence, who needs people in Earth orbit? 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: 18 Aug 92 17:46:54 GMT From: Mike Schatz Subject: Apollo Video Clips Newsgroups: sci.space Does anyone know where I might obtain the video clip from one of the Apollo lunar landing missions where an astronaut dropped a feather and a hammer simultaneously? (I would like to show this to a physics class I'm teaching this fall--it's a nice illustration of the Law of Universal Gravitation) Thanks Mike schatz@chaos.utexas.edu ------------------------------ Date: Fri, 21 Aug 92 23:34:00 EDT From: Thierry Lach Subject: Asteroid report Newsgroups: sci.space forrie@morwyn.uucp (Forrie Aldrich) writes: > Recently, and associate mentioned there was a report of a rather large > asteroid (or some object) approaching or within our solar system, and > with a trajectory currently in our direction. And that radio signals > have been transmitted from said object. > > This does sound a little out-of-the-ordinary, can someone confirm or > deny this? (for those familar with Arthur C. Clark, the above reference > makes me have visions of RAMA heading our way... ::wince:: ;) > > Thank you. > > -- > ----------- Forrest Aldrich ----------- > ------- morwyn!forrie@unhtel.unh.edu ------- > ---- ---- > -- VISION GRAPHICS -- Dover, NH - USA -- > ------------------------------------------------------ or maybe Niven and Pournelle (_Footfall_) ? ------------------------------ Date: 22 Aug 92 04:54:30 GMT From: Dave Tholen Subject: Asteroid report Newsgroups: sci.space Forrie Aldrich writes: > Recently, and associate mentioned there was a report of a rather large > asteroid (or some object) approaching or within our solar system, and > with a trajectory currently in our direction. And that radio signals > have been transmitted from said object. > > This does sound a little out-of-the-ordinary, can someone confirm or > deny this? (for those familar with Arthur C. Clark, the above reference > makes me have visions of RAMA heading our way... ::wince:: ;) Probably was referring to the close approach of 4179 Toutatis on December 8. The radio signals coming from it will be the radar waves bounced off of it by Steve Ostro. It (nor any other asteroid) has transmitted anything to Earth all by itself. ------------------------------ Date: 22 Aug 92 03:02:34 GMT From: William Lewis Subject: BuckyStalks (was Re: Beanstalks in Nevada Sky) Newsgroups: sci.space In article <1700@aviary.Stars.Reston.Unisys.COM> munck@stars.reston.unisys.com writes: >Suppose we came up with a (Buckytube-based) material strong enough to >make an Earth beanstalk, and it could be manufactured in mega-kilo lots >for pennies per kilo. How could we use it to get into space? Is there >any small-scale, bootstrapping approach that avoids involvement with >Big Dump Organizations like NASA and the US Govt.? The big problem with synchronous tethers (besides the sheer amount of material) is probably building them. This is essentially a 22,000-MILE high version of the "Indian rope trick"; the only proposals I've ever seen have been vague mumblings about capturing an appropriately-composed asteroid or comet-piece into geosynchronous orbit and manufacturing the tether there, lowering it as it's built (simultaneously moving the rock-and-factory's orbit outwards, of course). This is definitely not a bootstrappable activity; you have to get a whole industry into orbit before you get *any* return in the form of a usable tether. >OK, suppose we had that material AND Cold Fusion producing kilowatts >per cc. ... Well, why didn't you SAY so?!? We could build the tether around a temporary Lofstrom loop. Or, we could build the tether on the ground, laid out flat (we'll rent the Equator) and put it in orbit via repulsion against the Earth's magnetic field. =8) =8) =8) --- Seriously, since I'm posting this anyway, does anyone know of any cleverer (or at least easier) ways to get a beanstalk built than the extrude-it-from-Geosynch approach? Specifically, anything that would let us keep the factory on the ground? -- email: wiml@u.washington.edu | Home: Seattle, Washington | (William Lewis) | 47 41' 15" N 122 42' 58" W | NeXTmail: wiml@ingalls.cs.washington.edu `-------------------------------' --*-- Member, Coalition to Preserve Semantic Vacuity --*-- ------------------------------ Date: 22 Aug 92 04:46:39 GMT From: Mike Santangelo Subject: Energya and Freedom and Soyuz ACRV and... Newsgroups: sci.space aws@iti.org (Allen W. Sherzer) writes: >In article <1992Aug17.154937.24078@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes: >>Indeed. If we follow the plan of using Soyuz and HL Deltas, the Shuttle >>fleet is *gone*. >OK, I have posted extensive numbers on the alternatives. Let's see some >numbers from you. What will the Shuttle do that will not only justify the huge >expense of keeping it but also pay for the opportunity cost of the cheaper >infrastructure? >I await your reply. >>With this plan 3/4 of the >>Shuttle fleet is available for other work than servicing Fred. >Shuttle flies about eight times a year (at least it has for the last >2 years and looks like it will do so this year). Since using Shuttle >as the ACRV will about half the number of flights there will be NO >non station shuttle flights. >Thus we will be spending $5 billion each and every year to resuply the >station. That's an interesting number since you could build the >Porche of ACRV's for that and could do ALL your tasks for 20% of that >figure. >>As to the $65 million firm price for Soyuz, I've posted about this >>several times. >1. That is about three times the price I have seen for a Soyuz. I am >assuming $100M per Atlas/Soyuz launch even though the actual cost will >likely be much closer to $75 million. >2. We are stuck with Soyuz anyway since we won't get an ACRV. Probably true, but I will remain skeptical about its inclusion into Fred's support infrastructure until I see it go up, and probably remain that way until someone/some people come down in one (one would hope as a dry run and not due to a real emergency). >3. Lots can be done to mitigate this. We can sign long term contracts, >build in the US under licence, or a number of other alternatives. What do you think the tooling cost is going to be to make them? Russian fabrication <> american, I would think this would be non-trivial in terms of start-up time. Once american workers are put to the task with big aerospace contractors to manage them you can probably bet that the Soyuz manufacture is going to get pretty uncomptetive pretty quickly, especially if you factor in start-up and tooling costs. I would also assume this would take quite a few years before the first american produced Soyuz rolls off the line. No, I think we should let the Russians keep making them, labor costs are bound to stay low at least in the near term, also give them something to do and some hard currency. Geez I hope they (the Russians) spend ALOT of time making all the instrumentation readable (clearly, well translated) in English. Including all the needed documentation. How would these systems be certified in the US? Has anyone given thought to training logistics with regard to piloting the things? Would they take place in Russia or the US? I take it this is factored into the overall cost? I've been reading this thread for sometime and really hadn't seen any of the last several topics discussed. Just seems kinda 'assumed'. -- +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Michael F. Santangelo + Internet: mike@socrates.umd.edu Computer & Network Systems Admin + mike@cbl.umd.edu CBL / CEES (Solomons Island) + mike@kavishar.umd.edu ------------------------------ Date: 21 Aug 92 23:50:03 GMT From: jrm@gnv.ifas.ufl.edu Subject: Inflatable Space Stations - Why Not ? Newsgroups: sci.space In article , ruca@pinkie.saber-si.pt (Rui Sousa) writes: > In article <1992Aug19.183403.1527@gnv.ifas.ufl.edu> jrm@gnv.ifas.ufl.edu writes: > >> Whatever became of the idea of inflatable space habitats/workstations ? >> The savings on initial cost and on launch weight should be very great. >> Add to that the large size and configurational possibilities and you >> have an incredibly good deal. Modern materials, esp tri-weave carbon >> fiber, could strengthen an envelope and protect against ripping or >> [...] > Well, I think NASA has been doing some nice research on how several materials > cope with LEO atomic oxygen and radiation. If it turns out those THIN walls > can't do it, it would have been too soon to talk about inflatable structures > ... > Despite that possibility (I hope those materials can do it) the idea seems fascinating from the ecenomic point of view! I have heard a number of people claim that atomic oxygen would be a problem for inflatable space stations. While this is a very reactive substance, I cannot imagine that a suitible protective coating is unavailible. Even a few microns of vapor-deposited gold should supply considerable resistance to atomic oxygen. Vapor-deposition also allows stuff like silicon dioxide, aluminum oxide or other ceramics to be 'painted' on. I have never seen any reports about how well stable plastics like teflon cope with O-1 ... though you would have to overcoat it with aluminum or gold to keep the UV away. If O-1 is such a stickie-wickie though, the obvious solution is to opt for a higher orbit. Proper disposition of equipment and water/fuel chambers around the exterior perimiter would give considerable radiation protection - probably better than for 'Freedom'. At a higher orbit, these large-volume structures would be ideal 'warehouses' for spare materials and could be used as a refuge in case some prob made it impossible to leave orbit in a shuttle - stuck doors, main engine failure, heavy tile damage etc.. Anyway, this idea, or slightly armored versions of it, seem so incredibly economical and simple that only evil politics could be behind their suppression - not engineering probs. One poster claimed to me that Livermore Labs had claimed inflatables could supply all the functionality of 'Freedom' for 1/10 the cost ... and they were told to butt out. With money tight - it is obvious that there is a lot more interest by contractors in stealing every availible penny of govt money they can than there is a dream of a new frontier. Ten 'Freedom' equivalent stations instead of just one ultra-expensive, vibration-plagued, ultra-custom station would do a lot to further the utility of space. Write your congresspersons and senators ... tell them you have heard of this better way ... tell them you are disinclined to vote for people that spend ten times what is required for projects. The incumbents are more afraid for their jobs this year than in a very long time. Voter leverage is magnified. Take advantage. -- Jim Mason ------------------------------ Date: Sat, 22 Aug 1992 01:52:29 GMT From: Josh 'K' Hopkins Subject: Opinions on NLS Newsgroups: sci.space I've been noticing a distinct lack of discussion on the New (or is it National?) Launch System in this group, which kind of surprises me given the number of other topics that are discussed. AIAA's journal has published two major articles on NLS recently, both very upbeat. They discussed the lower costs, high reliability, and the Keep It Simple Stupid aprroach (though I don't think they called it that). From the figures I've seen, it looks like the smallest of the launch vehicles would be a nice commercial rocket and the largest has potential for SEI. What AIAA has said about the STME (Space Transportation Main Engine) is also similarly flattering. Well, as you may know, I tend to get suspicious whenever someone is particularly gung ho or especially down on a project, and I'm always skeptical about vaporware, but I'd like some facts to base my decisions on. Would anyone like to volunteer an opinion? (yeah, I know - dumb question :) -- Josh Hopkins j-hopkins@uiuc.edu, or jbh55289@uxa.cso.uiuc.edu "A goal is a dream taken seriously." -Uncle Walt. ------------------------------ Date: Sat, 22 Aug 1992 01:17:04 GMT From: Josh 'K' Hopkins Subject: Private space ventures Newsgroups: sci.space games@max.u.washington.edu writes: [on the subject of getting Perot to invest in space - I've changed the order of a few statements for clarity] >If I can convince Mr Perot that it is in his best interest to solve the drought >problem in africa, then he will do so, If I can convince him that it is in >his best interest to start a space program, then he will do so. Believe it or not, personal gain isn't the only things some people base their decisions on. Whatever other problems Perot may have, he did strike me as someone who did things because he thought they were "right," at least once in a while. However, space doesn't tend to lend itself to this kind of motivation, because it takes such a large amount of money and because there just aren't that many things you can do that give people a warm fuzzy feeling. >Why pick on Perot. Why not Bill Gates. Well, the fact is that Gates (for >example) doesn't spend his money on non computer related investments. Period. Actually, according to the internal IBM equivalent of netnews, Gates has started investing in movies in the last few months. >In fact, there are others that might even be better candidates, like the >prince of that little island who has 29B and is the worlds richest man. He's a sultan, the place is Brunei and it doesn't actually cover the whole island, but you still get extra credit. >Why don't we pick on him? I think we're missing the point. What space needs more than a rich investor is a temporarily poor one. When we have the space equivalent of a Bill Gates or Ross Perot, who starts of small but makes a big fortune fairly quickly in a new field, then we'll have the space revolution we're looking for. Other people would jump on the bandwagon, competition develops and boom - you get your 486DX 33 booster for less than the price of a present day Apple II launch vehicle. Unfortunately, analogies only go so far. If space is an analogous field, we don't have a young Bill Gates that I can see. -- Josh Hopkins j-hopkins@uiuc.edu, or jbh55289@uxa.cso.uiuc.edu "A goal is a dream taken seriously." -Uncle Walt. ------------------------------ Date: 22 Aug 92 04:04:25 GMT From: William Lewis Subject: Tethers Newsgroups: sci.space (In response to a post asserting that non-equatorial beanstalks would have to be held up by thrusters or other forms of "cheating") In article <1547@hsvaic.boeing.com> eder@hsvaic.boeing.com (Dani Eder) writes: >I do not believe this is correct. It is true that the center of >gravity of the 'beanstalk' needs to be in Clarke Orbit so it does >not wobble. The attachment point on the ground, however, can be >off the equator. You elevator in this case will form a catenary, >i.e. it will be curved. This will require more structure than the >simpler vertical case, so it is not usually considered, but it is >not ruled out on physical grounds. Well, it is true that a beanstalk with "nearly zero" force at the attachment point has to be anchored at the equator. I'm not familiar with modern anchoring methods, but I suspect that, given the magnitudes of forces involved in a tether, we can't handle anything except "nearly zero". (It's possible to arrange for a tether to have zero force at its attachment, but IMHO real tethers will probably want to be under tension, to provide a margin of safety and payload. This tension can be made as small as you want however.) I've worked out the equations for a more or less ideal equatorial beanstalk (brief summary of results: Kevlar isn't quite strong enough to be practical, but the equation is exponential and a factor-of-ten improvement of strength-to-weight ratio ("scale height") looks like it WOULD be pretty practical.) on paper, but I made heavy use of symmetry arguments so they're not applicable to "off center" beanstalks. One Of These Days I'll get around to putting a general version of the equations into Mathematica... but I suspect that it would be possible to anchor a tether in Nevada, as long as you don't mind having it lean over. The question, I guess, is whether you can make it lean shallowly enough to stay in Nevada's airspace. -- email: wiml@u.washington.edu | Home: Seattle, Washington | (William Lewis) | 47 41' 15" N 122 42' 58" W | NeXTmail: wiml@ingalls.cs.washington.edu `-------------------------------' --*-- Member, Coalition to Preserve Semantic Vacuity --*-- ------------------------------ Date: 22 Aug 92 01:21:00 GMT From: wingo%cspara.decnet@Fedex.Msfc.Nasa.Gov Subject: Viable alternatives to space? Was ( Re: Private Space Ventures) Newsgroups: sci.space In article <8780.2339210127@kcbbs.gen.nz>, Simon_Demler@kcbbs.gen.nz (Simon Demler) writes... >> [It bugs me that there are people like H Ross Perot, who >> themselves have enough cash to finance their own space >> programs, but that none, so far, has underwritten one.] > >Does it also bother you that these people could be spending some money >on the drought problems in Africa rather than on some space program...You >must be one of those space for the sake of space of types... > >Come on get real...there are MUCH larger problems that need solving >on this planet before trying to get peoples private wealth for space >purposes.. > Yes that is the argument that was used in 1972 to end the Apollo and look how much progress has been made with the seven trillion dollars that has been spent by the American government to end poverty here in the old income redistribution system. Yes we can proudly point to the government owned welfare ghetto's where 90% of all murders in America take place and where over 70% of all drug trafficking comes from. Yes this argument is the primary reason the American Government is 4 trillion dollars in debt. Yes the problems are large and yes they do need to be solved, but you only have to read this group for a few days to see that there are many on here trying to do just that, solve the problems of the planet by expanding the domain of man. This process is as old as Phonecian and Greek colonization and trade. Where else is the wealth available to input into the earth's system to raise the standard of living and help those poor Africans that you are so concerned about coming from? What ya gonna do, send Norman Schwartzkopf over there to end the anarchy? Go into debt another few billion to feed the hungry over there today that will just need another infusion next year? What is your alternative? How would you spend the fifteen billion dollars that NASA gets a year to help the people? What do you propose? Let us know and in the flame cauldron of sci.space maybe we can learn enough toall be saved from a useless life of supporting the progress of mankind. Dennis Wingo, University of Alabama in Huntsville ------------------------------ Date: 22 Aug 92 01:28:44 GMT From: Josh 'K' Hopkins Subject: What happened to Viking? Newsgroups: sci.space eugene@wilbur.nas.nasa.gov (Eugene N. Miya) writes: >In article <1992Aug20.233734.691@ringer.cs.utsa.edu> >burris@ennex1.eng.utsa.edu (John Burris) writes: >>What happened the Viking spacecraft? >Both lands and orbiters were shut down for lack of funds and the need to use >the antenna resources for other projects (Galileo, Magellan, power >distribution experiments, SETI, etc.) Wait a minute. Neither Gallileo nor Magellan were major customers of the Deep Space Network ten years ago. According to "Quest For Space," lander 1 stopped transmitting on 19 Nov, 1982, orbiter 1 on 7 Aug, 1980. Lander 2 stopped in April of 1980 and orbiter 2 on 7 July 1981. I'm quite certain all of these were spacecraft failures, not shutdowns and the fact that the dates are spread over more than 2 years supports that. The landers weren't transmitting anything but meteorological data by the time they died, so they wouldn't have been using much antenna time or money. -- Josh Hopkins j-hopkins@uiuc.edu, or jbh55289@uxa.cso.uiuc.edu "A goal is a dream taken seriously." -Uncle Walt. ------------------------------ Date: 22 Aug 92 06:46:29 GMT From: George William Herbert Subject: With telepresence, who needs people in Earth orbit? Newsgroups: sci.space cecil@physics.unc.edu (Gerald Cecil) writes: >gwh@soda.berkeley.edu (George William Herbert) writes: >>Have you talked to someone who builds or works with space robotics? >No, I was hoping that there might be someone out there who would counteract >hype from virtual-reality types. Ok. >>When anyone suggests replacing humans in the short term, they laugh. >>Space robotics aren't as strong, for the most part, have less degrees >>of freedom _and_ less limbs, less end effector dexterity, and more >>likely failure points than a man in space. They're safer, but often >>can't do the job. (note that an astronaut in EVA can't do everything >>either. both together are much more capable.) >OK, fine. But the only current `job' for SSF is apparently biological >research on the long-term effects on microgravity, which means loading >rats into a centrifuge. I submit that that can be done with a conveyor >belt. Sure, you need people to (dextrously) put the station together >(or at least to install the rats in their cages), but after that its all >BF Skinner (push the bar, get the food pellet, wait for the scalpel). Microgravity biology most certainly is not the only thing that's going to be done on Freedom 8-) There's going to be space and earth science (both with maintenance needs), materials science, (with maintenance and operational needs) and biology with maintenance and operational tending needs. Let's look at Bio first. Fine control teleoperation isn't very advanced; I'm not aware of anyone who's done even simple surgery or inserting an IV line or needs via telepresense. I'm not saying it's impossible, but we need a much higher degree of sensors, feedback, mobility, and reaction time than what we have now. One hand gloved three-fingered hand and fuzzy monocular vision aren't all that useful. Especially with a potential six second delay in the loop, much smaller than the average rat's squirm time. (Why six seconds? Well, once to TRDSS, once down to TDRSS ground station, once back to geostationary to a comsat and down again to NASA's center (Johnson?) who's doing station ops, and then a second while a NASA computer integrity checks the data. And then back again with your response 8-) (I agree that the delay is too long. Talk to the NASA Freedom telerobotics people about it. The people at Rice and UTexas and Johnson who are playing with a prototype system agree but haven't been able to shorten that delay yet). And then there are the maintenance problems. Ok. Ignoring other detail problems, here's a neat experiment to try and see how difficult this can be. Imagine that you've got a bundle of wires that's worked loose and needs to be tied to a structural member. Simulate this with two sticks about 2 feet (0.6 meter) long. Get some friends to hold these. Now, you have some string with which you're going to attach the cable bundle to the structure. Take one hand (this is a one armed robot) and put three gloves on it (or one ski glove). Lie down on your back, have your friends hold the two sticks nearly at your full arms reach. Tie the string around the two objects with one hand and two fingers. Oh, and you can't cheat and use gravity. Your friends have to enforce not letting you use gravity. If you can't do this (hint: about one person in three could last time I saw the demo) try with five fingers. Or with two hands with two fingers each. A more accurate version allows two arms with two fingers, but blindfolds the person who's holding (someone else has to teleoperate him). The scary part is that EVA ops aren't much easier. But in a pressurized environment, people have a lot of advantages. >>Or are you just trying to start a flamewar? >Well, I'm certainly getting sick of some of the topics that have been >battered to death here. We seem to be going round and round on how to >supply SSF or get the crew away when things fall apart. I'd still like >to see a discussion of *why*, in the present scheme of things, people are >necessary for Earth orbit operations. Seems to me you could (in the spirit >of many discussions in this group) free up a lot of $ (possibly some small >fraction of which could be used to improve the dexterity of robots.) This >is, after all, sci.space, not sci.humansinspace.waiting4Soyuz People are necessary because space is a hard plase to work. Things don't work the same there, in ways that we don't totally understand yet. Robots, especially ones at a distance, are hard to use for aforementione reasons. They also break. We can't get away (now) with just using robots in space. We also can't do as much with just people as you can with both people and robots. If you think that space operations are going to increase in general, it might be wise to fund both EVA and robotics more than they're funded now. Both have a long ways to go, and which one is best in the end I cannot predict 8-) -george william herbert gwh@soda.berkeley.edu gwh@lurnix.com ------------------------------ End of Space Digest Volume 15 : Issue 136 ------------------------------