Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from holmes.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr1/ota/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr1/ota/space/space.dl) (->ota+space.digests) ID ; Tue, 28 Feb 89 03:17:03 -0500 (EST) Message-ID: Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Tue, 28 Feb 89 03:16:53 -0500 (EST) Subject: SPACE Digest V9 #265 SPACE Digest Volume 9 : Issue 265 Today's Topics: Re: Manned vs unmanned space exploration Re: An integrated space program for the world Re: the un/manned debate Re: Orbital debris study completed (Forwarded) Re: Space colonies NASA, Soviets, gripes Re: Synthetic Aperture Radar Re: the un/manned debate Re: 1992 moon base Re: Voyager Images Re: What ever happened to NERVA? Re: approaching "C" ---------------------------------------------------------------------- Date: 22 Feb 89 17:58:33 GMT From: mailrus!jarvis.csri.toronto.edu!utgpu!utzoo!henry@tut.cis.ohio-state.edu (Henry Spencer) Subject: Re: Manned vs unmanned space exploration In article <8288@polyslo.CalPoly.EDU> jmckerna@polyslo.CalPoly.EDU (John McKernan) writes: >... It's interesting to think about how little of NASA would >be left if all launch activities, the unmanned space program, and the space >station were removed. Yeah, you'd be left with just the technology R&D... supposedly NASA's primary purpose in life... > In my opinion the station is premature at current launch >costs, and I know some of Henry's postings have been critical of it, though I >can't say for sure whether he supports building the station now or not. I have deeply mixed feelings about the current space station project. I don't consider launch costs a major factor, though -- that's not a big part of the budget for it. I don't think it's impossible to build a good and relatively economical space station at current launch costs, but I don't think NASA can. The space-station concept I liked was Art Dula's: you keep the hardware costs modest by having it built by construction companies instead of aerospace contractors, and you get cheap and prompt launches by buying them from the Soviets. -- The Earth is our mother; | Henry Spencer at U of Toronto Zoology our nine months are up. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 22 Feb 89 21:48:54 GMT From: minke!szabonj@beaver.cs.washington.edu (Nick Szabo) Subject: Re: An integrated space program for the world In article <8902221734.AA18412@cs.nps.navy.mil> shimeall@CS.NPS.NAVY.MIL (Tim Shimeall x2509) writes: [Concerning "terraforming" the Sahara] >I'll also invite you to consider the social effects of converting the >Sahara into farmland. There are widespread and ancient cultures built >around desert life, with many active advocates. I don't think that >they'll welcome the sacrifice of their culture. > >Note that these criticisms apply ONLY to the Sahara reclamation >process. Terraforming Mars involves nothing close to these political >problems. Actually, similar problems might arise, if the project to terraform Mars starts after the first Martian settlements are already laid down. Granted, these won't be ancient cultures, but imagine crashing comets or seeding genetically engineered organisms (to name just a couple of terraforming techniques) onto an already inhabited planet. These issues may need to be resolved before the first Mars bases and settlements are laid down. Should the terraformation of Mars be sacrificed for the sake of its first settlers? Or vice-versa? Nick Szabo szabonj@fred.cs.washington.edu ------------------------------ Date: 22 Feb 89 17:34:17 GMT From: mailrus!jarvis.csri.toronto.edu!utgpu!utzoo!henry@tut.cis.ohio-state.edu (Henry Spencer) Subject: Re: the un/manned debate In article <8287@polyslo.CalPoly.EDU> jmckerna@polyslo.CalPoly.EDU (John McKernan) writes: >... The focus of unmanned space today is launching >probes with the launchers we have now, not building new launchers. In fact, one sometimes gets the impression that unmanned space today isn't interested in *anything* that won't help their current missions. Give them all the money they want, and they'll still be flying the same sort of missions a century from now. :-) "We can't fund your new technology because no current mission requires it. And of course we can't design it into any of our missions until it's developed properly. And of course our current missions should have priority over developing it." -- The Earth is our mother; | Henry Spencer at U of Toronto Zoology our nine months are up. | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 22 Feb 89 08:32:50 GMT From: portal!cup.portal.com!hkhenson@uunet.uu.net (H Keith Henson) Subject: Re: Orbital debris study completed (Forwarded) A proposal I have not seen (doesn't mean it hasn't been made) to clean up orbital debris would be to construct one large ground based laser and a few orbital redirection mirrows. Very small stuff could be vaporized, but even the large pieces could be de-orbited and dumped into the atomosphere by vaporizing a small fraction of the junk on the forward (in orbit) side. There should be several groups that could support this project. The laser would be useful for launching material, and it would provide definative answers to many SDI projects. One system would not be enough for significant defense, so those opposing SDI might not fight it. And after all, it is a cleanup project, so we might get environmental support. Keith Henson, a founder of the L5 Society ------------------------------ Date: 22 Feb 89 06:06:13 GMT From: blake!ogccse!littlei!omepd!psu-cs!reed!mehawk@beaver.cs.washington.edu (Michael Sandy) Subject: Re: Space colonies In article <1989Jan20.101034.10384@cs.rochester.edu> dietz@cs.rochester.edu (Paul Dietz) writes: >>According to my sources existing technology *is* more or less adequate >>to the task of building space colonies -- at least there are no >>"show-stoppers" --, it's just that they're not *affordable*. What's >>needed is cheaper space transportation, more experience working in >>space, and a good economic motive for building them. > >I consider orders of magnitude too expensive == inadequate by orders >of magnitude. > >We don't need experience if that experience will not be applied for >decades. Consider all the experience gained in Apollo, and subsequently >lost, because it wasn't "steam engine time". > > Paul F. Dietz > dietz@cs.rochester.edu Hi! I just started reading this newsgroup, but since I recently read an article relevant to this discussion, I thought I'd share. There already is a "much cheaper space transportation technology" in the works, like 20$ per pound of payload to get to orbit. Its based on the good 'ole electromagnetic railgun. The current technology can get small (~1 pound) objects up to 4 miles per second by accelerating them at 48,000 g. Current technology, and technology that can easily be developed in the next ten years can make semi-conductors and other electronic packages capable of withstanding that acceleration. A launch facility that could launch payloads of up to a ton could be built for 300 million dollars, a fraction of the space shuttle cost. Used in conjunction with the shuttle, with the shuttle transporting such fragile things as humans and the rail launcher the more massive stuff, we could redo the moon launch project like it was originally intended. The original plan had the US first establishing space stations as refueling points. With a cheap method for getting fuel into orbit and other new technologies like the ion drive the solar system is back in reach again. The article in question was the February 1989 Discover. Michael Sandy mehawk@reed.uucp ------------------------------ Date: 23 Feb 89 05:29:11 GMT From: silver!matzatt@iuvax.cs.indiana.edu (thomas matzat) Subject: NASA, Soviets, gripes Here we sit, waiting patiently for the next shuttle launch, while the Soviets have tested not only a new HLV, but their own shuttle. As much as I hate to say it, the Soviet space program has got NASA beat bad. I say this because I'm really sick of seeing NASA, and the U.S. government in general, screw up time and time again! The Soviets have built up a great deal of confidence in their equipment over the years, to the point where they can test their shuttle on a booster that's only being launched for the second time, and do it all by remote control. Hell, we can't even launch a satellite on a Titan II without worrying about it blowing up! The Soviet space program has built itself up the slow, but cautious way by basing the next generation of lifter and spacecraft on the previous design. It has been slow, but it has worked. NASA started out that way, but got hooked on the glitz and promise of the shuttle. Developing new technology is fine, but NASA was in such a rush to "beat the Russians", that they lost sight of what they should have been doing: Improving on the Saturn V and putting up a space station a bit more permanent than Skylab. Instead, they scrap our only REAL HLV and go all out for the space shuttle, a plan which hurt NASA in the long run. Now NASA is in a position where it will take them twice as long as the Soviets to put up a "real" space station. With Energia and Buran, the Soviets could build a large station in no time at all. Mir could serve as the base for all of this construction. Just add a few modules, and presto, instant large scale space station. Right now I believe NASA can do one of two things: 1) Spend large sums of money on bringing back the Saturn V or building an HLV from scratch, and getting the space program going in the right direction again. or 2) Work together with the Soviets , ESA, and any other space program that wants to get in on the act, because it's going to take more money than any one country can come up with to really explore space in the right way. (My definition of the "right way" is by moving from space stations, to a Moon base, to Mars, etc. in an organized, cautious, and PERMANENT manner.) These are my ramblings on this whole affair. If I have offended anyone, I apologize. If you have a different opinion, I'd like to hear it. -Tom "the illogical one" !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ! Thomas R. Matzat ! UUCP: {inuxc,rutgers,pyramid,pur-ee}! ! ! Indiana University ! iuvax!silver!matzatt ! ! Bloomington, In. ! ARPA: matzatt@silver.bacs.indiana.edu ! !!!!!!!!!!!!!!!!!!!!!!!!!! BITNET: matzatt@iubacs.BITNET ! ! ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! DISCLAIMER: These are my opinions only. (Who else would want them?) ------------------------------ Date: 22 Feb 89 21:27:07 GMT From: math.ucla.edu!julia!hgw@cs.ucla.edu (Harold Wong) Subject: Re: Synthetic Aperture Radar In article <27230@sgi.SGI.COM> mitch@rock.SGI.COM (Tom Mitchell) writes: >In article <404@Portia.Stanford.EDU>, joe@hanauma.stanford.edu (Joe Dellinger) writes: > >The best way to research this is a computer search on the "Palmdale >Bulge". There was a large bunch of articles c.5 years back when >someone noted that geodedic leveling indicated a 'uplift' of a >large area adjadcent to the San Andreas fault. > >As always only believe a bit of what you read, > If my source is correct, the Palmdale Bulge turned out to be an error in instrumentation. It's suppose to be a long story. Anybody else know anything about it? ------------------------------------------------------------------------------- Harold Wong (213) 825-9040 UCLA-Mathnet; 3915F MSA; 405 Hilgard Ave.; Los Angeles, CA 90024-1555 ARPA: hgw@math.ucla.edu BITNET: hgw%math.ucla.edu@INTERBIT ------------------------------ Date: 23 Feb 89 04:20:01 GMT From: minke!szabonj@beaver.cs.washington.edu (Nick Szabo) Subject: Re: the un/manned debate In article <1989Feb22.173417.9049@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >one sometimes gets the impression that unmanned space today isn't >interested in *anything* that won't help their current missions. You are caught up in your own rhetoric, Henry. I can't speak for specific scientists, but unmanned activities in general are far more future-oriented than manned projects, which exist mainly to satisfy the present pleasure of witnessing a few people in space. The future-oriented aspects of our space program--private industry in space, exploration of the entire solar system instead of just LEO, the development of deep-space communications and operations, etc.--are unmanned. You will note that I have not been advocating *just* unmanned; I have been advocating unmanned *and* basic R&D. Both have been shafted by funding priorities. (As an aside, note that the development of EML and gas-gun technology is far more relevant to unmanned than manned activities. Cheap unmanned launch methods will enable us to send thousands of probes to all corners of the solar system, and later to launch automated prospecting and mining missions.) Nick Szabo szabonj@fred.cs.washington.edu ------------------------------ Date: 22 Feb 89 17:50:12 GMT From: mahendo!jato!jpl-devvax!lwall@elroy.jpl.nasa.gov (Larry Wall) Subject: Re: 1992 moon base : >While earth-operated rovers may be slower, they could be operated around : >the clock (at least during the lunar day). Earth-bound operators would be : >many times less expensive than lunar colonists. : : I fail to see why rovers couldn't be operated around the clock, : period. Putting searchlights on them is no big deal. You'd almost certaintly want to keep them operating to avoid getting them too cold. Even if nothing is overtly damaged by the cold, the thermal cycle is vicious. Unless you make the rovers so they can dig in for the lunar night, of course. Even then, you want to produce enough heat to offset what is lost through whatever insulation you've collected around the rover. On the other hand, if you've designed them to run at night, the problem may be to get rid of the excess heat during the day... Larry Wall lwall@jpl-devvax.jpl.nasa.gov ------------------------------ Date: Thu, 23 Feb 89 10:11:03 PDT From: Peter Scott Subject: Re: Voyager Images X-Vms-Mail-To: EXOS%"space@andrew.cmu.edu" Cc: romeo!currier@duke.cs.duke.edu romeo!currier@cs.duke.edu (Bob Currier - DCAC Network Comm. Specialist) writes: >Does anyone know if the Voyager images are available to the public? >If so, can they be obtained in machine-readable format, i.e. 9 track >tape, or better yet, by anonymous FTP? For that matter, are there >*ANY* images available free of charge, or for a modest fee that can be >had for experimentation with image processing? > >We want to use our new NeXt box to play with the images... The Voyager Imaging Library here says that the images are not available in machine-readable form to the public at present, *however*, the NSSDC *does* plan to release them on CD-ROM in the near future. Peter Scott (pjs@grouch.jpl.nasa.gov) ------------------------------ Date: 23 Feb 89 00:21:49 GMT From: amdcad!weitek!sci!daver@ucbvax.Berkeley.EDU (Dave Rickel) Subject: Re: What ever happened to NERVA? I had heard that NERVA, in spite of having such a good specific impulse (the number posted (800 sec) (ick--specific impulse should be a velocity) looks to be about twice that of the SSME--did i mess up in the conversion somewhere?), was no better, and indeed a bit worse, than a chemical rocket. The problem was that the NERVA engine was much heavier than a conventional chemical rocket engine with the same thrust; in most of the proposed missions you could get better (and more reliable) performance by using a chemical rocket and some extra fuel. Of course, that's an unfair comparison--comparing a mature technology (chemical rockets) to a developing technology (nuclear rockets), but what the hell. The anti-nuclear movement of the 60's certainly didn't help NERVA along any. david rickel decwrl!sci!daver ------------------------------ Date: 22 Feb 89 01:34:56 GMT From: tektronix!tekig5!robina@ucbvax.Berkeley.EDU (Robin Adams) Subject: Re: approaching "C" A space ship is travelling through space at 75% light speed. It is headed toward our moon and is 50,000 miles distant. A powerful laser is mounted at the front of the space ship. When the beam is switched on, the light should reach the moon in approximately 0.27 seconds. Regardless of where any observer is, the photons in the beam would appear to impact the surface at a speed greater than "C" (This is a kind of Michelson - Morley experiment out in the open). If it does'nt, it seems like the ship would pile into its own photons. - Did I miss something? o o o o o o o o ---------------------------------------------------------------------------- | | | | Robin /---------\ Adams ------------------------------ End of SPACE Digest V9 #265 *******************