Date: Thu, 11 Mar 93 05:00:04 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V16 #299 To: Space Digest Readers Precedence: bulk Space Digest Thu, 11 Mar 93 Volume 16 : Issue 299 Today's Topics: Earth Moon anim under X11 (2 msgs) Gift to Aliens (was Re: Pluto Fast Flyby post-flyby fate) Huygens Lunar Ice Transport (2 msgs) Mars exploration Pluto Fast Flyby post-flyby fate Road & Track road tests 1996 JPL Rocky IV Microrover (2 msgs) Rocket Propulsion (3 msgs) Sodium in exhaust Soviet Energia: Available for Commercial Use? (2 msgs) SSF Resupply (Was Re: Nobody cares about Fred?) Student Design Project (was Re: Lunar Ice Transport) Tether power The courage of anonymity 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: 10 Mar 93 06:10:00 GMT From: Michael Nolan Subject: Earth Moon anim under X11 Newsgroups: sci.astro,sci.space In article (Uwe Schuerkamp) writes: > >I installed th xanim package (Version 2.29) and tried to get it to run >the emconj.flc from ames.arc... Xanim barfs with something like... > >Next question: What is this xanim.Z at ames:/pub/SPACE/SOFTWARE >supposed to be? A compressed tar file? Any help would be greatly >appreciated. The xanim.Z is a compressed sun/sparc executable. I put it there because I thought some people might like to run it without installing the package, but that information got lost in translation. You need xanim rev 2.29.7, which is not trivial to find, lots of sites have old versions. I tried archie on xanim229, and all of the ones I tried were old. The correct version of xanim is available as sunsite.unc.edu:/pub/multimedia/utilities/xanim.tar.Z and I will send it to Ron Baalke, but I can't get in to ames.arc.nasa.gov right now, so that might take a little while. ------------------------------ Date: 10 Mar 1993 17:55 UT From: Ron Baalke Subject: Earth Moon anim under X11 Newsgroups: sci.astro,sci.space In article <1993Mar10.061000.6065@organpipe.uug.arizona.edu>, nolan@LPL.Arizona.EDU (Michael Nolan) writes... >In article (Uwe Schuerkamp) writes: >> >>I installed th xanim package (Version 2.29) and tried to get it to run >>the emconj.flc from ames.arc... Xanim barfs with something like... >> >>Next question: What is this xanim.Z at ames:/pub/SPACE/SOFTWARE >>supposed to be? A compressed tar file? Any help would be greatly >>appreciated. > >The correct version of xanim is available as >sunsite.unc.edu:/pub/multimedia/utilities/xanim.tar.Z > >and I will send it to Ron Baalke, but I can't get in to ames.arc.nasa.gov >right now, so that might take a little while. The most recent version of xanim is now in the /pub/SPACE/SOFTWARE directory at Ames. ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |__ M/S 525-3684 Telos | It's kind of fun to do /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | the impossible. |_____|/ |_|/ |_____|/ | Walt Disney ------------------------------ Date: 10 Mar 93 04:02:05 GMT From: Bill Higgins-- Beam Jockey Subject: Gift to Aliens (was Re: Pluto Fast Flyby post-flyby fate) Newsgroups: sci.space In article <2032@tnc.UUCP>, m0102@tnc.UUCP (FRANK NEY) writes: [on sending a SETI message along on the Pluto Fast Flyby probes] > > 300 grams, huh? I think we can fit in a CD-ROM and instructions for > that kind of weight. > > Only 1/2 B-) here: I think this might really be a worthwhile project, > especially if some of us on the outside can put up some bucks and > volunteeer time. > > Who's with me? There remains the problem of what to put on the CD-ROM. How about a few hundred K of Usenet postings discussing the PFF mission? I think I can dig them out of the archives... The House Telecommunications Subcommittee | has scheduled a hearing on the issue for | Bill Higgins next Wednesday, featuring advocates of | Fermilab tougher regulation as well as Shari | higgins@fnal.fnal.gov Lewis, host of a children's show on public | higgins@fnal.bitnet television, and her sock puppet Lamb Chop. --*N.Y. Times*, 4 Mar 93, p. A9 ------------------------------ Date: 10 Mar 93 11:59:59 GMT From: "R.D.Lorenz" Subject: Huygens Newsgroups: sci.space Will Huygens float (continued) As far as I know, all solids likely to be abundant on outer planet satellites will sink in an ethane ocean. 'Fluffy' material that could retain some 'air' might well float - I am sure there is some intersting physics (solubity, surface tension etc) to be done here. (Optical evidence, and modelling and experiments indicate that the aerosols that make the atmosphere opaque at visible wavelengths as seen from space, suggests that the haze particles may have a fractal geometry - maybe this is efficient at trapping air?) Whether the imager is immersed or not depends on whether you prefer pictures of the sea surface and sky, or a murky undersea picture (probably v. dark - especially if the ocean is aerosol- laden) Models suggest noontime illumination at the surface of Titan of about 10% of the solar flux. This approximates to 100x full moonlight on Earth. Note that the experiments to determine ocean composition (if we do indeed land in an ocean) WANT to be immersed - these experiments are near the base of the probe. The DISR is on the top half. Note also that the antenna should be near vertical, to maximise the probability of keeping the radio link open (the antenna beamwidth is wide, but finite) Impact speed, on a small drogue parachute for stability, is 5m/s. You get this by dropping something from a height of 1m on Earth (very handy for my impact force experiments!) If we hit something hard, though, the probe may well not survive. The probe does not include buoyancy tanks, but does contain a lot of light foam, for thermal insulation. There is a radar altimeter, for sequencing experiment operations only (not a science instrument itself) The payload comprises DISR - optical/IR camera and spectrometer (plus lots of other stuff for measuring haze thickness etc.) GCMS - all-singing all-dancing composition analyser ACP - Aerosol collector and Pyrolyser HASI - Huygens Atmospheric Structure Instrument - Acceleration (entry) temperature, pressure, electrical activity SSP - surface science package - physical properties of surface DWE - Doppler Wind Experiment - winds For some papers on the probe design, see ESA SP-338 (proceedings of the conference on Titan, Toulouse, France, September 1991). There should be an up-to-date article on the probe in the Autumn issue of the ESA bulletin. Hope this helps. ralph Lorenz Unit for Space Sciences University of Kent, UK ------------------------------ Date: Tue, 9 Mar 1993 22:32:46 GMT From: Uwe Bonnes Subject: Lunar Ice Transport Newsgroups: sci.space In article <1993Mar9.200156.2749@sol.UVic.CA>, rborden@uglx.UVic.CA (Ross Borden) writes: |> In all the Lunar ice transportation proposals that I've seen, |> nobody has mentioned what would be, on Earth, the most obvious: overland |> hauling. |> To maintain high through-put, a continuous stream of vehicles |> would haul ice from the polar ice mines to the equatorial processing |> plants, and then dead-head back (unless there was some return cargo.) |> The trucks would be big. A standard tractor pulls a trailer |> with a cargo area 8'x8'x40'-60', plus that again with a super-B. The more stuff deleted ???? is this sci.fiction??? Uwe Bonnes bon@lte.e-technik.uni-erlangen.de ------------------------------ Date: 10 Mar 93 10:18:25 GMT From: J DARRINGTON Subject: Lunar Ice Transport Newsgroups: sci.space Ross Borden (rborden@uglx.UVic.CA) wrote: : In all the Lunar ice transportation proposals that I've seen, : nobody has mentioned what would be, on Earth, the most obvious: overland : hauling. : To maintain high through-put, a continuous stream of vehicles : would haul ice from the polar ice mines to the equatorial processing : plants, and then dead-head back (unless there was some return cargo.) Sorry, but I must have missed out on the lead up to this thread - why do we want to put/move ice on the moon?????? Bemused but fascinated. Jon. ------------------------------ Date: 10 Mar 93 16:25:24 GMT From: Gary Coffman Subject: Mars exploration Newsgroups: sci.space In article szabo@techbook.com (Nick Szabo) writes: >gary@ke4zv.uucp (Gary Coffman) writes: > >>In 1969 no one had even heard of VR telepresence. We still don't do it >>very well. One of the larger problems even today is dealing with the >>time lag for feedback. Round trip speed of light time to the Moon is >>on the order of 2.5 seconds, it's over 4 minutes round trip to Mars >>at closest approach. Decoupling your movement commands with your >>perceptions by such a temporal displacement makes a mockery of >>telepresence. > >In some ways yes, in some ways no. Check out the MIT Press >journal _Prescence_, especially the paper in the first volume on >"teleprogramming". A good VR simulations is combined with a >modicum of on-site knowledge of the near-term environment, and >a good error-notification and correction protocol between the >user and the telebot. This is mostly being tested for 3-10 sec. delays, >which are typically for oil industry undersea sonar telepresence, but >similar principles can be used for longer delays. The problem is that you run out of the knowledge area of the simulation faster than you can communicate new data when the distances stretch to light minutes, or the terrain is rough and your sight lines are short. This in turn means you operate extremely slowly and reaction to an unpredicted slip or subsidence will be minutes too late to prevent disaster. Rather than VR telepresence, you are reduced to pre-programmed move and wait strategies with at least semi-autonomous disaster avoidance on board the remote system. This is much less flexible and robust than telepresence in near real time. >>A combination of the ever mythical AI > >You never cease to attack strawmen, do you? (a) techniques >associated with AI, such as robots, expert systems, neural >nets, etc. are a thriving $multi-billion commercial industry, >not "mythical", and (b) there is nothing about telepresence >that requires theoretical breakthrough; it's primarily a matter >of software hacking and improving hardware thruput. The limitations of rule based systems and neural networks of sufficient complexity to deal with unexpected occurances are extreme. Nothing approaching the AI capabilities promised by AI researchers 30 years ago has yet been developed. Now some researchers are saying it'll be here in 30 more years. Where have we heard this before? There is indeed nothing about telepresence that requires theoretical breakthrus, for short delay times, but when the delays start to exceed a couple of seconds, or the environment of the remote is unstructured or complex, then reality rears it's ugly head. Ordinary response time has to be stretched inordinately, and emergency response is impossible except by autonomous on board systems. And those are always "30 years away". >>VR >>telepresence seems unlikely to play a major role in forthcoming >>missions. > >You'll have to let astronaut Pete Conrad know, so he can >stop developing his VR telepilot system for DC-X. Glad to, "Pete, forget it, it's a rathole for cubic money when you exceed radio controlled model airplane ranges." Gary -- Gary Coffman KE4ZV | You make it, | gatech!wa4mei!ke4zv!gary Destructive Testing Systems | we break it. | uunet!rsiatl!ke4zv!gary 534 Shannon Way | Guaranteed! | emory!kd4nc!ke4zv!gary Lawrenceville, GA 30244 | | ------------------------------ Date: 10 Mar 93 13:21:24 GMT From: FRANK NEY Subject: Pluto Fast Flyby post-flyby fate Newsgroups: sci.space 300 grams, huh? I think we can fit in a CD-ROM and instructions for that kind of weight. Only 1/2 B-) here: I think this might really be a worthwhile project, especially if some of us on the outside can put up some bucks and volunteeer time. Who's with me? Frank Ney N4ZHG EMT-A LPVa NRA ILA GOA CCRTKBA "M-O-U-S-E" ---------------------------------------------------------------- If you don't think women explode, try dropping one! -- The Next Challenge - Public Access Unix in Northern Va. - Washington D.C. 703-803-0391 To log in for trial and account info. ------------------------------ Date: 10 Mar 93 16:10:36 GMT From: "Simon E. Booth" Subject: Road & Track road tests 1996 JPL Rocky IV Microrover Newsgroups: sci.space In article WHITEMAN%IPFWVM@UICVM.UIC.EDU ("S.K. Whiteman") writes: >For anyone who in interested the April 1993 issue of Road & Track >contains a road test of the Microrover. Some of the stats: > >Price as tested: $2,500,000 >Top speed 0.037 MPH >0 to 0.037 mph like right now >1/4 mile 24,139.0 sec > >All-in-all the article is not as tongue in cheek as one might >expect. I thought it was interesting. BTW Road & Track does something like this every April (an April Fool's joke). Ususally though it's been something that's not even remotely related to cars. A couple of years ago they had road test of (no joke!!) a dogsled. Actually, the rover article covered alot of technical ground in a serious manner, but I still got some laughs out of seeing automotive terminology applied to the rover. I never realized the rover was so small though! :-) Simon ------------------------------ Date: Wed, 10 Mar 1993 16:32:08 GMT From: Bruce Dunn Subject: Road & Track road tests 1996 JPL Rocky IV Microrover Newsgroups: sci.space > S.K. Whiteman writes: > For anyone who in interested the April 1993 issue of Road & Track > contains a road test of the Microrover. Some of the stats: > > Price as tested: $2,500,000 > Top speed 0.037 MPH > 0 to 0.037 mph like right now > 1/4 mile 24,139.0 sec > > All-in-all the article is not as tongue in cheek as one might > expect. > Road and Track has being doing these oddball "roadtests" for years. One year they tested the Goodyear blimp. I think that best one was the issue in which the front cover of the magazine promised a road test of a "Mercedes 18 liter GT". It turned out that the vehicle was from the Mercedes commercial truck division, and that "GT" stood for "Garbage Truck". -- Bruce Dunn Vancouver, Canada Bruce_Dunn@mindlink.bc.ca ------------------------------ Date: Wed, 10 Mar 1993 13:23:31 GMT From: "John S. Neff" Subject: Rocket Propulsion Newsgroups: sci.space In article <1njuevINNihd@elroy.jpl.nasa.gov> tjt@scn1.Jpl.Nasa.Gov (Tim Thompson) writes: >From: tjt@scn1.Jpl.Nasa.Gov (Tim Thompson) >Subject: Re: Rocket Propulsion >Date: 10 Mar 1993 05:31:11 GMT >In article Cnq@eis.calstate.edu, glam@eis.calstate.edu (Gibson Lam) writes: >> I am a student doing a research project on Goddard, the man who first >> invented rocket propulsion. Of all the eventual uses that rocket >> propulsion made possible, such as war missiles or the space shuttle, does >> anyone think that Goddard should be responsible for the eventual uses of >> his invention? I would also appretiate any information that you could >> give me on Goddard or rocket propulsion. > > Do you mean by "responsible", something like "since rockets were made into >weapons of war, It's all Goddard's fault". Or perhaps "Thank Goddard for space >flight"? No, I don't think Goddard should be responsible. With precious few >exceptions, how can any inventor anticipate the use/misuse to which his/her >inventions will be put? > >--- >ALL OPINIONS ARE MINE! ALL MINE !!!! HOWEVER, YOU ARE WELCOME TO SHARE THEM. >------------------------------------------------------------ >Timothy J. Thompson, Earth and Space Sciences Division, JPL. >Assistant Administrator, Division Science Computing Network. >Secretary, Los Angeles Astronomical Society. >Member, BOD, Mount Wilson Observatory Association. > >INTERnet/BITnet: tjt@scn1.jpl.nasa.gov >NSI/DECnet: jplsc8::tim >SCREAMnet: YO!! TIM!! >GPSnet: 118:10:22.85 W by 34:11:58.27 N > Rockets were invented by the Chinese and were used in the War of 1812 by the Brits. Remember the "Rockets Red Glare" in our natioal anthem. These were solid fueled rockets(i.e. tubes full of gunpower) not liquid fueled rockets that Goddard developed. ------------------------------ Date: 10 Mar 93 16:28:59 GMT From: Henry Spencer Subject: Rocket Propulsion Newsgroups: sci.space In article glam@eis.calstate.edu (Gibson Lam) writes: > I am a student doing a research project on Goddard, the man who first >invented rocket propulsion... The first thing you need to do is find out what Goddard actually did. :-) He invented the liquid-fueled rocket, not the rocket. >anyone think that Goddard should be responsible for the eventual uses of >his invention? ... Since *all* technology has military applications, it's really pretty silly to blame an inventor because the military found a way to use his work. (Or to call a technology evil because it was developed by the military -- you *do* know who developed the techniques for mass production of antibiotics, don't you?) Do we blame the Wright Brothers for Hiroshima? -- C++ is the best example of second-system| Henry Spencer @ U of Toronto Zoology effect since OS/360. | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 10 Mar 93 17:10:06 GMT From: Gary Coffman Subject: Rocket Propulsion Newsgroups: sci.space In article glam@eis.calstate.edu (Gibson Lam) writes: > I am a student doing a research project on Goddard, the man who first >invented rocket propulsion. Of all the eventual uses that rocket >propulsion made possible, such as war missiles or the space shuttle, does >anyone think that Goddard should be responsible for the eventual uses of >his invention? I would also appretiate any information that you could >give me on Goddard or rocket propulsion. Ahem, Goddard didn't invent rocket propulsion, some Chinese guy about 2,000 years ago did. Goddard was one of several early twentieth century experimenters working with *liquid fueled* rockets with the intent of achieving extra-atmospheric flight. The Chinese used rockets in war many centuries before Goddard was born. The British used war rockets to bombard Fort McHenry on September 13, 1814 which is where the phrase "the rocket's red glare" in the Star Spangled Banner comes from. For more information, see Rocket in any Encyclopedia. Gary -- Gary Coffman KE4ZV | You make it, | gatech!wa4mei!ke4zv!gary Destructive Testing Systems | we break it. | uunet!rsiatl!ke4zv!gary 534 Shannon Way | Guaranteed! | emory!kd4nc!ke4zv!gary Lawrenceville, GA 30244 | | ------------------------------ Date: 10 Mar 93 12:00:55 GMT From: "R.D.Lorenz" Subject: Sodium in exhaust Newsgroups: sci.space Sodium contaminants in rocket exhaust? Does anyone have any information/references on the presence of sodium in rocket exhaust (either solid or liquid) I can understand that the binder, the Ammonium Perchlorate, or the aluminium in a solid rocket motor could be contaminated with sodium, but I have never seen any data on this ? Also, is there any reason sodium compounds might be a contaminant of dinitrogen tetroxide or nitric acid oxidisers, or hydrazine- based fuels ? Please respond by email (rdl1@ukc.ac.uk) as I don't often read news. Thanks Ralph Lorenz ------------------------------ Date: 10 Mar 93 16:31:30 GMT From: "Simon E. Booth" Subject: Soviet Energia: Available for Commercial Use? Newsgroups: sci.space In article <1nitgcINNh1t@access.digex.com> prb@access.digex.com (Pat) writes: > >Problem with energiya, is there is alimited test base for the rocket. >it hasn't gone through a full qualification program. > >Some of the big Com Sat proposals could use a big ELV, and a lot >of other programs could use something like it, but it needs to be demonstrated My question is how would payloads be mated to an Energia? The Buran shuttle This seems cumbersome, unless perhaps the module itself is designed to function as some sort of unmanned orbiter rather than simply a launch shroud. One last comment- A while back I read an article in Omni written by, and along with the article was a rough design for a Mars spacecraft. This hypothetical craft was desgined for launch by an Energia. Direct-ascent interplantary flight? Interesting concept! (now if we could only get that with a DC-variant- no need for the Energia!) Simon ------------------------------ Date: 10 Mar 93 16:42:47 GMT From: "Simon E. Booth" Subject: Soviet Energia: Available for Commercial Use? Newsgroups: sci.space In article <1993Mar10.163130.2265@ringer.cs.utsa.edu> sbooth@lonestar.utsa.edu (Simon E. Booth) writes: >In article <1nitgcINNh1t@access.digex.com> prb@access.digex.com (Pat) writes: > >Problem with energiya, is there is alimited test base for the rocket. >it hasn't gone through a full qualification program. > >Some of the big Com Sat proposals could use a big ELV, and a lot >of other programs could use something like it, but it needs to be demonstrated My question is how would payloads be mated to an Energia? The Buran shuttle is of course attached the same way the US shuttle is mated to its fuel tank, but I recall seeing an illustration of Energia just prior to its first flight in early 1988 (minus Buran of course). This diagram showed a payload module attached to where a shuttle would normally be positioned. This seems cumbersome, unless perhaps the module itself is designed to function as some sort of unmanned orbiter rather than simply a launch shroud. BTW- are we to assume that Energia evolved out of the N-1? Unless I'm mistaken, N-1 was supposed to exceed the launch thrust of the Saturn V, something like 9 or 10 million pounds of thrust vs. the Saturn's 7.5 million. One last comment- A while back I read an article in Omni written by, and along with the article was a rough design for a Mars spacecraft. This hypothetical craft was desgined for launch by an Energia. Direct-ascent interplantary flight? Interesting concept! (now if we could only get that with a DC-variant- no need for the Energia!) :-) Simon ------------------------------ Date: Wed, 10 Mar 1993 16:42:07 GMT From: Greg Moore Subject: SSF Resupply (Was Re: Nobody cares about Fred?) Newsgroups: sci.space In article <1993Mar5.210713.11711@iti.org> aws@iti.org (Allen W. Sherzer) writes: >In article <1993Mar5.171553.17933@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes: > >>>has shown that Freedom can be built on schedule for $2B per year *IF* >>>all the money where spent on Freedom. > >>>Now this is what they have been getting from Congress for the past >>>few years and are likely to get for the next few years. If the money >>>where spent wisely we would have a station. > >>Back to the chart: > >The chart isn't relevant. Average the money received over the past >three years (including this year) and you get a sum very close to >what NASA says is needed. Include next years funding and it goes over >the top. > Oh, come on Allen, you know better than that. Tell you what, I need to hire you for 3 years. The salary is $60,000 a year. Well, that's what it averages too. The first year I'm only going to pay you $10,000 a year. The second year maybe I'll pay you $20,000. The final year I'll pay you the rest. Can you life on this? Can you make the ends meet? Avereging over the years doesn't work. >For the next ten years $2B per year IS an achieveable figure and would >allow NASA to build the station *IF* they would spend the money on >Freedom. I note that you don't seem to be bothered that NASA, by its >own estimates, is wasting upwards of a third of the funds allocated. > > Allen > >-- >+---------------------------------------------------------------------------+ >| Allen W. Sherzer | "A great man is one who does nothing but leaves | >| aws@iti.org | nothing undone" | >+----------------------102 DAYS TO FIRST FLIGHT OF DCX----------------------+ ------------------------------ Date: 10 Mar 93 03:58:02 GMT From: Bill Higgins-- Beam Jockey Subject: Student Design Project (was Re: Lunar Ice Transport) Newsgroups: sci.space In article <1993Mar10.101825.3222@bradford.ac.uk>, J.Darrington@bradford.ac.uk (J DARRINGTON) writes: > Ross Borden (rborden@uglx.UVic.CA) wrote: > : In all the Lunar ice transportation proposals that I've seen, > : nobody has mentioned what would be, on Earth, the most obvious: overland > : hauling. > Sorry, but I must have missed out on the lead up to this thread - why do > we want to put/move ice on the moon?????? You did. A professor at the University of Cincinnati has assigned a design project to a bunch of engineering students. Several of the students have been asking sci.space readers for advice. The project's assumptions include: 1. A source of water ice at the poles of the Moon. [This is scientifically plausible; evidence does not yet rule it out.] 2. It must be moved to a lunar base at the lunar equator for processing into rocket propellant (and perhaps other useful products?). [This is completely senseless; obviously the processing should be done at the poles, near the "ice mines."] Since the object of the game is to teach young designers to work to a customer's specifications, I see nothing inherently wrong with assumption 2. It's a shame, though, that their scenario isn't more realistic; if it were, they could present their results at technical conferences. Okay, Cincinnati, did I get it right? P.S. If your professor can offer some good reason why assumption 2 is *not* dumb, the Net would like to hear from him or her! -- O~~* /_) ' / / /_/ ' , , ' ,_ _ \|/ - ~ -~~~~~~~~~~~/_) / / / / / / (_) (_) / / / _\~~~~~~~~~~~zap! / \ (_) (_) / | \ | | Bill Higgins Fermi National Accelerator Laboratory \ / Bitnet: HIGGINS@FNAL.BITNET - - Internet: HIGGINS@FNAL.FNAL.GOV ~ SPAN/Hepnet: 43011::HIGGINS ------------------------------ Date: Wed, 10 Mar 1993 14:57:46 GMT From: Zach K Subject: Tether power Newsgroups: sci.space jbh55289@uxa.cso.uiuc.edu (Josh Hopkins) writes: >fcrary@ucsu.Colorado.EDU (Frank Crary) writes: >>Using a tether to generate power actually increases the need for >>reboosts: The current creates an IxB force (essentially an >>electromagnetic drag) which slows the station. >This is of course true. However, if you replace the solar arrays with a tether >you are also eliminating a large source of drag. I would presume that the >net drag still increases, but has anyone actually done the calculations to >show it? I have not done the calculations but I would think It would be better to use solar for power and the tether to maintain the orbit. Zach ------------------------------ Date: 10 Mar 93 16:44:18 GMT From: Melinda Shore Subject: The courage of anonymity Newsgroups: comp.org.eff.talk,sci.space,alt.privacy In article <0fbDGXy00WBME5t8sq@andrew.cmu.edu> Nicholas Kramer writes: > And I ask you: How many people here give different weight to ideas on >Usenet based on the author? I do, often. Over the years you come to know that certain people know what they're talking about, while others are monomaniacal crackpots. It seems obvious to me that anonymity is often a good thing, especially in areas where people do have something valid to say but have legitimate reasons to fear the consequences if their identity is known (and yes, it does happen). The problem, though, is less one of authority than it is responsibility. People who dissasociate their identities from their postings no longer need to be as responsible, and the results of that are the kinds of content-free flamers that show up, for example, in the gay-related newsgroups. This is a problem that I'd very much like to see go away - nobody should post unless they're willing and able to take responsibility for the contents of their articles. Period. -- Melinda Shore - Cornell Theory Center - shore@tc.cornell.edu ------------------------------ End of Space Digest Volume 16 : Issue 299 ------------------------------