Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from hogtown.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests) ID ; Sat, 6 Apr 91 02:03:50 -0500 (EST) Message-ID: <4bzL=FS00WBwI9PE5F@andrew.cmu.edu> Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Sat, 6 Apr 91 02:03:45 -0500 (EST) Subject: SPACE Digest V13 #368 SPACE Digest Volume 13 : Issue 368 Today's Topics: Re: One Small Step for a Space Activist... Vol 2 No 4 Face on Mars Re: More cost/lb. follies Re: Commercial Space News (1 of 5) Re: Nuclear Rockets GEOMAGNETIC STORM UPDATE - STORM HAS ENDED Re: Commercial Space news (5 of 12) space news from Feb 18 AW&ST Re: Underground Nuclear Test in Nevada Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription requests, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Date: 4 Apr 91 01:18:38 GMT From: unisoft!fai!sequent!crg5!szabo@ucbvax.Berkeley.EDU (Nick Szabo) Subject: Re: One Small Step for a Space Activist... Vol 2 No 4 In article <10257@hub.ucsb.edu> 3001crad@ucsbuxa.ucsb.edu (Charles Frank Radley) writes: >I am puzzled about complaints that nobody is proposing >"real" hardware and schedules for SEI. The following >paragraph answers the question - everybody has been holding off >waiting for the synthesis report....... Nobody seriously expects a Manned Mars Mission to be funded at anything within an order of magnitude of the present pricetag. I know if I seriously expected it, I would be screaming bloody murder over such a colossal waste of resources. Meanwhile, some interesting technology many come out of SEI, if they can work some prototypes in between all the papers being passed back and forth. So for now, a research-oriented SEI is quite worthwhile. -- Nick Szabo szabo@sequent.com "If you want oil, drill lots of wells" -- J. Paul Getty The above opinions are my own and not related to those of any organization I may be affiliated with. ------------------------------ Date: Fri, 5 Apr 91 17:31 GMT From: AMON Subject: Face on Mars I'm not going to say yea or nay to whether it is or isn't. But some incorrect statements have been made. First, there are TWO images that show it, in different lighting and different angles. 35A72 and 70A13. The image processing work done on these was done from raw data, and I have seen stunning 3D reconstructions. The "face" and 5 sides pyramid do indeed "look" like the names suggest. I will not claim they are or aren't. I would very much love to see more photos of this area. The Hoagland book is a bit extreme and mines these two photos for several hundred pages of text. It tries to create a civilization out of them and some of the resampling techniques used in the image analysis may have led to artifacts, in particular the "grid" structure in one enhanced image. Regardless of that, I'm impressed by the visual impact of the images. They most likely aren't anything by rocks of interesting shape, like the Kermit the frog look alike someone mentioned a few years ago. ANyone who is interested should dig in the Space Digest archive for the previous go around on this between myself, Phil Karn and others, circ 1988 or so. Ad Astra, Dale Amon ------------------------------ Date: 27 Mar 91 18:10:51 GMT From: usc!hacgate!ashtate!dbase!michaelw@ucsd.edu (Michael Wallis) Subject: Re: More cost/lb. follies szabo@crg5.UUCP (Nick Szabo) writes: >* We need 4 orders of magnitude drop from today's costs for space > colonization to be affordable. >* Chemical rockets can provide less than an order of magnitude drop > between now and the end of the 21st century >On the first point, divide the cost of a hypothetical Shuttle/OTV >trip to L-5 ($40 million/person) with round trip first-class from >Tokyo to New York ($2,000/person) to get 4 orders of magnitude. I'm intrigued about where you got the $40 million/person figure. I thought the going price was about $12 million (nearly half an order of magnitude drop right there). And I think an analogy to a $14,000 around the world cruise would be more appropriate. (BTW, New York-Tokyo First Class on United is $2766 ONE WAY as of 27 March 91.) >Plug in more precise numbers if you like, but all of these results >fall within an order of magnitude of current launch costs. A safe >conclusion is that costs/lb. will not drop by more than an order of >magnitude. Even a factor of 5 is improbable: I will lay bets with any >takers that unsubsidized chem rocket costs will never drop below $1,000/lb. >(long before 2100 they will be replaced by something better). Well ... I think it's a wonderful proof for the need for single stage reusable vehicles. We can do about 20% of current costs ($1000/lb) now and can improve that significantly with a little tinkering. I also question your assumption that 4 orders of magnitude (50 cents/lb!) are needed to open space. One order of magnitude (to $500/lb) would be sufficient to start the development of space and that's certainly reachable this decade. Two orders (to $50/lb) may be achievable early next decade by volume and mass production alone. I agree that the third order of magnitude (to $5/lb) is likely beyond the reach of chemical reactions, but I don't see you proposing any alternative. >Until we develop a method much better than chemical rockets, we must >be damned smart about what we launch, and search for all opportunities >to let the solar system do the work for us. I agree entirely, but let us not feel we must rely on NASA and the aging Shuttle fleet as the backbone of space exploration. For the price of one shuttle launch (~ $500 million) we could (read I can) develop far better reusable vehicles and open the doorway to space development. ------------------------------------------------------------------------------- Michael Wallis INTERNET: michaelw@dbase.A-T.COM Computer Consultant CI$: 75470,1264 Santa Clara, CA USA bix: mwallis "Frankly, I'd rather be building rockets!" #include "standard disclaimer" -- ------------------------------------------------------------------------------- Michael Wallis INTERNET: michaelw@dbase.A-T.COM Computer Consultant CI$: 75470,1264 Santa Clara, CA USA bix: mwallis ------------------------------ Date: 4 Apr 91 17:03:06 GMT From: usc!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!emory!wa4mei!ke4zv!gary@apple.com (Gary Coffman) Subject: Re: Commercial Space News (1 of 5) In article <2883.27F6AE83@ofa123.fidonet.org> Wales.Larrison@ofa123.fidonet.org (Wales Larrison) writes: >------------------------------------------------------------------ >OSC REVEALS PROTOTYPE TO COMMERCIAL COMMUNICATIONS SATELLITE > Orbital Sciences Corp (OSC) recently showed off its experimental >precursor of a small, low-orbiting store/dump communications >satellite. As described by OSC, the ORBCOMM-X satellite is about 35 >lbs in weight and use about 8 watts of power. It is planned for >launch as a "hitchhiker" smallsat payload on an upcoming Ariane-4 >launch in May. The Ariane will deploy the ORBCOMM-X satellite into >a polar orbit of about 480 miles altitude while inserting another >polar orbiting satellite. The ORBCOMM-X satellite will demonstrate >the capability to receive a communications from its ground station >in Virginia, store it, and then retransmit it to the ground on its >next pass. This will demonstrate prototype operations for a >proposed network of 20 similar satellites to provide continuous data >communications, messaging, and position determination to customers >worldwide. The amateur radio satellites called PACSAT are on orbit and operating using this technology. AMSAT, the amateur radio satellite organization, started the craze for light satellites by demonstrating the practicallity of small, light, spacecraft for remote communications, termed Microsats. In this series are store and forward digital communications satellites, a satellite with an earth observing camera, and a satellite with digitized voice capability. All are built using the same physical and electrical buss with stackable, interchangeable modules. This was all accomplished with volunteer labor and private funds. They are real, on orbit, and operating *today*. Ground terminals can be carried in a briefcase. Unless OSC has tapped into this base of knowledge and experience, they are re-inventing the wheel with their ORBCOMM-X program. Gary KE4ZV ------------------------------ Date: 5 Apr 91 22:39:10 GMT From: usc!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo!henry@ucsd.edu (Henry Spencer) Subject: Re: Nuclear Rockets In article <10933@ncar.ucar.edu> fhage@virga.rap.ucar.edu (Frank Hage) writes: > If a nuclear rocket develops thrust by vaporizing liquid hydrogen >passing over (through?) the reactor core, and the hydrogen acts >as the coolant, what keeps the reactor from melting "before ignition" >and after the LH fuel has run out? As with more conventional reactors, there are control rods that have a fair bit of say in how much heat is generated. Before startup, the rods are in and the reactor is quiet. At startup, they are withdrawn and things heat up. At shutdown, they are moved back in and things quiet down... almost. After the reactor has run for a while, there is some residual heat generated by fission products that cannot be shut off, and dissipating this heat somehow is an important design constraint. -- "The stories one hears about putting up | Henry Spencer @ U of Toronto Zoology SunOS 4.1.1 are all true." -D. Harrison| henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Fri, 5 Apr 91 15:28:37 MST From: oler <@BITNET.CC.CMU.EDU:oler@HG.ULeth.CA> (CARY OLER) Subject: GEOMAGNETIC STORM UPDATE - STORM HAS ENDED X-St-Vmsmail-To: st%"space+@andrew.cmu.edu" /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ GEOMAGNETIC STORM UPDATE Storm Alert Cancellation /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ 22:00 UT, 05 April ------------- STORM UPDATE INFORMATION: The geomagnetic storm has ended. Activity has returned to generally unsettled conditions. The period of most intense activity occurred within the first few hours of the interplanetary shock. Minor storming was observed for about six to nine hours following the SSC. Most of the magnetic storming was of low intensity, although higher latitudes did experience periods of major storming. Auroral activity was visible as far south as about 45 degrees north latitude. Generally moderate activity was observed over the northerly middle latitudes, while high latitudes experienced periods of high auroral activity. HF propagation conditions were not seriously affected by this minor storm. Higher latitudes experience the worst conditions, with significant flutter fading and higher than normal levels of absorption and noise. Conditions are returning to normal. No warnings are in progress at the present time. The following alerts remain IN PROGRESS: - SATELLITE PROTON EVENT ALERT /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ ------------------------------ Date: 6 Apr 91 01:27:45 GMT From: hub.ucsb.edu!ucsbuxa!3001crad@ucsd.edu (Charles Frank Radley) Subject: Re: Commercial Space news (5 of 12) Oh yes, when the ELV companies say they are not subsidized by the US govt, ask who owns their tooling....... A paraphrasing of Art Dula quoted in the LA Times. : ------------------------------ Date: 5 Apr 91 08:07:09 GMT From: dog.ee.lbl.gov!hellgate.utah.edu!caen!zaphod.mps.ohio-state.edu!rpi!news-server.csri.toronto.edu!utzoo!henry@ucbvax.Berkeley.EDU (Henry Spencer) Subject: space news from Feb 18 AW&ST [March issue of Spaceflight mentions that astronaut William F. Fisher has left NASA to return to medical practice. No big surprise, on thinking about it: he was co-chair of the group that reported the bad news about EVA requirements for Fred, which probably killed his chances of future flight assignments.] Editorial urging that SDIO get sensible about tactical-missile defence, dumping the silliness of applying Brilliant Pebbles to every problem and concentrating on urgent near-term availability of competent ground-based interceptors with better coverage than Patriot. Aerojet gets modest research contract from Army Strategic Defense to build a 33klb rocket engine using gel propellants, in the hopes that gels will give safer field handling than liquids while retaining stop-start and throttling capability. Bush signs new commercial space policy guidelines, stressing government purchase of commercial products and services when possible. OMB orders independent engineering review of NASA's EOS plan, reportedly to look particularly at the wisdom of large multi-sensor platforms. SDI estimates worldwide limited-attack protection system at $41G. The design target is complete destruction of a 200-warhead attack, including coverage for US territories, allies, and military forces in the field. Third-world tactical missiles and the possibility of accidental and unauthorized attacks from a politically-unstable Soviet Union are the major threats seen. The only real technical surprise is a willingness to consider shipboard and airborne launch platforms. Patriot succeeds as tactical missile interceptor in the Gulf, with a 100% interception rate for Scuds engaged over Saudi Arabia in the first three weeks of Desert Storm. (Some Scuds were not engaged because they were headed for water or open desert.) Study indicates that Navstar is not suitable for use by itself as a precision approach system for aircraft blind landings, although it could be very useful in combination with the new ground-based Microwave Landing System [which is somewhat controversial due to conversion costs from the older ILS now in use]. Various improved forms of Navstar, e.g. differential systems and phase-tracking receivers, could achieve "Category 1" accuracy, or nearly, but not "Category 3" [the really heavy-weather blind-landing standard]. The fundamental problem is that Cat 3 requires a maximum 2s delay between a system failure and a warning to aircraft on final approach, and even an extensive ground-receiver network with a new data link to the aircraft would have trouble meeting this. A further complication is that a satellite failure that kills Cat 3 capability at one airport will affect other airports in the area too. Finally, the non-military part of Navstar is not really accurate enough for Cat 3 even with differential methods, due to substantial altitude errors. It could, however, give much better accuracy than MLS for the early phases of landings, plus better coverage of possible abort trajectories in case of trouble, while leaving MLS (which gets more accurate as range closes) to handle final approach. Soviets reveal details of their N1 booster, meant as their Saturn V equivalent for manned lunar missions. The N1 used massive clustering of engines, and reliability problems in the 30 (!) first-stage engines were its Achilles' Heel. Early reports suggesting that the N1 would carry up the lunar spacecraft and rocket stages while a Soyuz launch carried the crew up appear to have been incorrect; it now appears that a single N1 launch would do the whole job. The first three stages would put a Soyuz, a lander, and three more rocket stages into Earth orbit. The fourth stage would boost the rest toward the Moon. The fifth would brake the rest into lunar orbit, and then do most of the deceleration of the lander, being jettisoned shortly before landing to crash on the Moon. [This "lunar crasher" approach was seriously considered for Apollo for a while.] The lander engine would then complete the landing, and later be used to boost back to lunar orbit. Finally, the sixth stage would boost the Soyuz back toward Earth. The total crew would be two, with only one descending to the lunar surface, and crew transfer between Soyuz and lander would be by EVA. [Actually, various elements of this resemble rejected alternatives in the US program; similar problems, similar solutions.] -- "The stories one hears about putting up | Henry Spencer @ U of Toronto Zoology SunOS 4.1.1 are all true." -D. Harrison| henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 5 Apr 91 20:15:54 GMT From: snorkelwacker.mit.edu!spool.mu.edu!cs.umn.edu!ariel.unm.edu!triton.unm.edu!prentice@apple.com (John Prentice) Subject: Re: Underground Nuclear Test in Nevada In article <1991Apr5.143519.25044@ecf.utoronto.ca> murty@ecf.toronto.edu (MURTY Hema Sandhyarani) writes: > > Yesterday there was another underground nuclear test in > Nevada. Why are we allowing this to continue? > > I am sure that if all the readers of sci.space got > together and denounces such tests by countries of > the world, they would have to stop. > Are you serious? Somehow I don't think the readers of sci.space have that kind of political clout! > > And, yes, I would like to hear arguments that any > might have in favor of these tests. What do they > accomplish in terms of science? They seem more > like muscle-flexing to me. > Why should they have ANY scientific value? The issue is not science, it is military. There are lots of reasons for testing weapons, not the least of which is verifying that the stockpile is still working. I am not advocating nuclear testing or denouncing it here, but your comment suggests that there is no plausible reason to do it and that is nonsense. That the U.S. and Soviets might be able to cease and not destabilize their deterrents, perhaps so. But the very fact that they are worried about this possiblity suggests that there are very real military concerns which nuclear testing addresses. I will say this. The arguments against nuclear weapons and weapons testing do not move me a great deal. I would be more impressed by attempts to eliminate world strife and the root causes of conflict than attempts to control the means by which nations wage war. I am also struck by the fact that for all the noise made over this issue in recent years, the really terrifying weapons are conventional, not nuclear. The chances of a nuclear war between the superpowers is almost nil and the consequences of a third world nation using a nuclear weapon, while serious, are not going to be affected in the least by what the superpowers do to limit or control their arsenals. On the other hand, the chances of conventional war in the world are obviously rather high. If one wants to make a difference in arms control, you would do better to address conventional weapons rather than getting wrapped up over exotic and unlikely ones. John -- John K. Prentice john@unmfys.unm.edu (Internet) Dept. of Physics and Astronomy, University of New Mexico, Albuquerque, NM, USA Computational Physics Group, Amparo Corporation, Albuquerque, NM, USA ------------------------------ End of SPACE Digest V13 #368 *******************