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 ; Tue, 26 Feb 91 02:00:07 -0500 (EST) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Tue, 26 Feb 91 02:00:03 -0500 (EST) Subject: SPACE Digest V13 #205 SPACE Digest Volume 13 : Issue 205 Today's Topics: Re: NASA A socialist bureaucracy (was : ONE SMALL STEP - REPLY) Celestron Telescopes Re: Government vs. Commercial R&D Re: dynasoar Galileo Update - 02/25/91 Re: Terraforming, sun shield Re: Commercially-funded Space Probes (was Re: Space Profits) re:m mystery? -dilemma Re: Commercially-funded Space Probes (was Re: Space Profits) 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: 26 Feb 91 03:26:51 GMT From: celit!dave@ucsd.edu (Dave Smith) Subject: Re: NASA A socialist bureaucracy (was : ONE SMALL STEP - REPLY) In article <1991Feb21.191128.14511@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >In article <44525@ut-emx.uucp> aoab314@ut-emx.uucp (Srinivas Bettadpur) writes: >>I wonder if a commercial company >>would take the risk of going into something as large in scope as the >>GPS system, which certainly has commercial applications... > >The problem with GPS is, how do you make money on it? Commercial >availability of GPS -- which is inherently difficult to charge for, since >receivers are entirely passive -- has largely destroyed the commercial >navsat market. Schemes like Geostar, in which your position is determined >by interaction with the satellites and they can refuse service if you haven't >paid your bill, are much more commercial but are having real trouble >getting started. Does anyone know if Iridium has a location mode built into the phones? That would be pretty handy. In fact, it could even be set up as a 976 number :-) -- David L. Smith FPS Computing, San Diego ucsd!celit!dave or dave@fps.com "It was time to stop playing games. It was time to put on funny hats and eat ice cream. Froggie played his oboe" - Richard Scarry ------------------------------ Date: 25 Feb 91 15:30:33 GMT From: wuarchive!zaphod.mps.ohio-state.edu!caen!news.cs.indiana.edu!maytag!alopeziz@eddie.mit.edu (Alex Lopez-Ortiz) Subject: Celestron Telescopes Are celestron telescopes any good? Are these the rigth newsgroups to ask? Thanks guys Alex University of Waterloo ------------------------------ Date: 25 Feb 91 15:54:55 GMT From: skipper!shafer@ames.arc.nasa.gov (Mary Shafer) Subject: Re: Government vs. Commercial R&D In article <21223@crg5.UUCP> szabo@crg5.UUCP (Nick Szabo) writes: Another source of resistance will be geographical sites that have been picked for political reasons, and don't necessarily correspond to good university or corporate centers. Fortuneately, we have a different set of people from different states in power right now. If we can match them to good universities, perhaps we can get somewhere with this. Well, some of the geographical sites were picked for operational reasons. Dryden for its lakebeds and restricted areas, Kennedy and Wallops for downrange safety, Ames for being on the opposite coast from Langley (WW II). Even the sites that were picked for political reasons probably can't be moved. Lewis's engine test cells, Langley's tunnels, etc. can't just be packed up and moved. Nobody that's in power now will want to bite the bullet and pay for all these things. Do you have any idea what a hypersonic tunnel costs? -- Mary Shafer shafer@skipper.dfrf.nasa.gov ames!skipper.dfrf.nasa.gov!shafer NASA Ames Dryden Flight Research Facility, Edwards, CA Of course I don't speak for NASA "A MiG at your six is better than no MiG at all"--Unknown US fighter pilot ------------------------------ Date: 24 Feb 91 20:53:44 GMT From: wuarchive!cs.utexas.edu!ut-emx!nowhere!sking@eddie.mit.edu (Steven King) Subject: Re: dynasoar In article <1991Feb20.215213.7459@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >In article <9102140928.AA05393@mozart.unx.sas.com> SNOMCB@mvs.sas.com (Mike Bishop) writes: >> Can anyone tell me what ever became of the Dynasoar project? >Dyna-Soar per se was killed, although low-level work on vaguely similar >things has continued. Its problem was the lack of a mission, since the >wingless spacecraft had already proved capable of doing almost everything >Dyna-Soar could have done. I'm afraid I'm going to disagree with Henry on this. DynaSoar had a mission; its the same mission that the Air Force currently uses aircraft for in the atmosphere. It had a limited payload capacity - you wouldnt have wanted to try building a space station with it, but it could take a pilot and 500? kg to LEO. Its advantage over its wingless contemporaries was that it wouldnt require anything near the recovery effort they did ( Naval assets that in an crisis might well be needed elsewhere ) as it could return to any friendly airfield. It would have been usefull anytime we needed to get a man tended payload into orbit fast, orbit a few times and then recover the package with a minimum effort. At that time there wasnt any treaties restricting the deployment of nuclear weapons in space, the Soviets were suspected of testing fractional orbital bombardment systems, and a military rivalry in space could have easily been the the outgrowth of the political rivalry. >> Was this an Air Force endevor? >Yes. This was a military project ( Air Force ) for military objectives ( principly reconnaissance ). It was terminated due to the decision to demilitarize America's space efforts. >> It seems this was some sort of forerunner of the Shuttle. >Only in a very loose way. Dyna-Soar would have gone up on top of a Titan; >it had no substantial propulsion system of its own. The DynaSoar was a lifting body design and was to use H2-O2 for its RCS. Not alot of fuel, but enough to change its orbit once the Titan got it there. One of the neat things about DynaSoar was that is used radiative and perspiration cooling for re-entry. The skin was of a metal chosen for its high emissivity and thermal charateristics ( with columbium for the nose and leading edges ). But it also had a "water-gel" blanket beneath that provided additional cooling. This was felt like material which was soaked with water and some sort of emulsifier to keep it from ending up at the tail of the vehicle after launch with an outer gasket layer and pressure release vents. As the heat radiated inward increased, the water would vaporize, build up pressure and vent. This system contributed only about 80kg to the launch weight but gave substancial cooling. The blankets were designed so that they could be easily changed out on recovery and the vehicle quickly serviced. Much of the vehicle was quite simple, even primitive by todays standards. There was a statement in one document to the effect that the cockpit enviromental control system would work better if the pilot kept his helmet visor closed. It was because of this simplicity that I was interested in the design. It seemed like a likely candidate to derive a private re-entry vehicle from. However, despite the project having been cancelled some 20 years earlier, most of the documents listed in the STAR were still classified. Its interesting that in some of the SDI literature, one sees a line drawing of a DynaSoar like vehicle atop a Titan like rocket... -- Look Ma! No .sig! ..!cs.utexas.edu!ut-emx!nowhere!sking ------------------------------ Date: 25 Feb 91 19:43:48 GMT From: usc!sdd.hp.com!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@ucsd.edu (Ron Baalke) Subject: Galileo Update - 02/25/91 GALILEO STATUS REPORT February 25, 1991 The health of the Galileo spacecraft continues to be excellent. Today's activities will consist of: o Performing a sun acquisition. o Turning on the star scanner high voltage. o Transitioning from all-spin to dual-spin operation. o Performing a cruise science memory readout for the EUV (Extreme Ultraviolet Spectrometer), MAG (Magnetometer), and DDS (Dust Detector) instruments. o Resetting the Command Loss Timer to 240 hours. Tomorrow, no spacecraft activity is planned. ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | Is it mind over matter, ___| | | | |__) |/ | | |___ M/S 301-355 | or matter over mind? /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | Never mind. |_____|/ |_|/ |_____|/ | It doesn't matter. ------------------------------ Date: 25 Feb 91 20:22:34 GMT From: snorkelwacker.mit.edu!thunder.mcrcim.mcgill.edu!bonnie.concordia.ca!news-server.csri.toronto.edu!helios.physics.utoronto.ca!aurora.physics.utoronto.ca!neufeld@bloom-beacon.mit.edu (Christopher Neufeld) Subject: Re: Terraforming, sun shield In article <5705@optilink.UUCP> cramer@optilink.UUCP (Clayton Cramer) writes: >In article <28676.27c07594@kuhub.cc.ukans.edu>, 2fmzmumble@kuhub.cc.ukans.edu writes: >> >> Problem: Terraform Venus. Method: Orbit a large shield in front of the sun >> to cut incident visible sunlight by 50%. Assume: Manufacturing and > >If you put it in orbit around Venus, it will, as they say, orbit >Venus -- so you don't have much of a shield several hours of the >day. If it is in orbit around the Sun, the problem becomes more >severe, since you won't have a shield for most of the year. (The >closer you are to the Sun, the faster it must revolve in order to >stay in orbit). > Nope. There's a point, the Sun-Venus L1 point, where an object much less massive than Venus will orbit the Sun with the same period as Venus itself, and lie between the Sun and Venus at all times. Because the radiation pressure on this disk would be considerable, the disk would have to lie somewhat sunward of the Sun-Venus L1 point. Mathematically, a solar sail oriented at normal incidence to the Sun orbits as if the Sun itself were less massive, so it can have the same period as a planet further out from the Sun, even ignoring that planet's gravitational influence in forming a Lagrange point. -- Christopher Neufeld....Just a graduate student | Note: new host. neufeld@aurora.physics.utoronto.ca Ad astra! | helios will still cneufeld@{pnet91,pro-cco}.cts.com | forward my mail to "Don't edit reality for the sake of simplicity" | me on aurora. ------------------------------ Date: 25 Feb 91 20:51:57 GMT From: idacrd!mac@princeton.edu (Robert McGwier) Subject: Re: Commercially-funded Space Probes (was Re: Space Profits) From article <1991Feb25.173823.29208@zoo.toronto.edu>, by henry@zoo.toronto.edu (Henry Spencer): > In article <21213@crg5.UUCP> szabo@crg5.UUCP (Nick Szabo) writes: >>Not at this time. Some effort is needed to bring deep space >>exploration down to the $10-50 million/probe range that universities, >>corporations, and other non-government organizations might consider. >>The major R&D items needed: >> >>* Microsatellite technology: >> -- standard microdevice bus >> -- small instruments >>* Upper stage for microsatellites >>* Pre/post calibration (target switching) and bandwidth upgrades to DSN >> to allow coverage of a much larger sky population > A Microsat bus is available from Interferometrics, Inc. in Vienna, Va. for about $1000000 (10^6) WITHOUT the instrument. Ariane will launch this package for about half a million on launches where an ASAP is available into either polar or geo-transfer orbit. The volume available for experiment in Microsat technology available from I^2 is VARIABLE since the unique modular construction allows them to be stacked several deep. Bob McGwier -- ____________________________________________________________________________ My opinions are my own no matter | Robert W. McGwier, N4HY who I work for! ;-) | CCR, AMSAT, etc. ---------------------------------------------------------------------------- ------------------------------ ReSent-Message-ID: Resent-Date: Mon, 25 Feb 91 09:52:50 EST Resent-From: Harold Pritchett Resent-To: Space discussion group Date: Sat, 23 Feb 91 02:28 CDT From: Subject: re:m mystery? -dilemma Original_To: BITNET%"space@finhutc" : As a space activist, however, I think these types of hype jobs raise : an interesting dilemma. ... : The fact is that such : things capture the publics attention and if we can answer meaningful : questions by visiting such areas then why not use it to build public : interest. ... : Further, the power I would hope that our integrity and credibility as scientists is more important than some cheap public relations. --Scott Cromar cromar@math.rutgers.edu ------------------------------ REPLY: Please do not misinterpret the question. I am not advocating the abandoment of morals, ethics, integrity or credibility. In fact I am advocating that we publically demonstrate these virtues. I have two reasons for posing such issues. First, I am and educator and spend much of my time teaching scientific methods/reasoning courses to undergraduates. My interest in things like the Mars face is as a class example of how evidence as "solid" as a photograph does not provide "proof" of anything. Through the past several years I have (as well as colleages) have been distressed my the increasing proportion of time that has to be spent teaching such fundamental reasoning skills to Sph, Jr. & Sr. university students. In fact, where I once spent perhaps one or two class periods /semester discussing such simplistic cases, I often spend 4 or 5 classes. Even then, I often have to address several students after hours on the reasoning that discredits the "obvious" interpretation. My second reason for being interested in the issue is because I am a space enthusiast who would like to see space exploration at the top of the national agenda again. I honestly believe that space exploration holds the potential for lessening many of our national and international woes (much as manifest destiny in the 1800's led to economic and cultural advances). My thinking is that we might identify a phenomenon, such as the mars face, which is located in an area that is important for several reasons. We allow the "phenomenon" to gain some public interest (which they seemed to do whether we want them to or not). In fact, the hype jobs about faces, alphabets, and photos of Heaven, are what make the news, and talkshows, while the really important findings remain out of public view. So let one catch the imagination of the public and then show how scientists can reason to what is a more probable explanation. -Kind of a national science demonstration. A comparison between what tabloids/intuitions/biases tell you and what empiricism/rationality predicts. Have the scientists give their reasoning and make their predictions and then test those predictions by actually going and investigating the site as part of a "more" serious investigation of the region. In short, for the past 15 years the hype and hoopla have gotten all the publicity and we have seen performance declines in academics and the work force. I see nothing wrong with making the public aware of the things that can be known and the improved decision making processes that can be gained by becoming proficient in rational thinking processes. Please don't misread my hypothetical scenario as an excuse to comprise one's scientific integrity. I am suggesting a way to showcase scientific reasoning and integrity in hopes of attracting more more people to the various scientific/technological disciplines (Much as the Moon race did in the '60s). My second hope is that finding such an issue might put space exploration back at the forefront of the national agenda, thereby providing a future for the continued expansion of human knowledge and growth for the world economy. ------------------------------ Date: 25 Feb 91 17:38:23 GMT From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utzoo!henry@apple.com (Henry Spencer) Subject: Re: Commercially-funded Space Probes (was Re: Space Profits) In article <21213@crg5.UUCP> szabo@crg5.UUCP (Nick Szabo) writes: >Not at this time. Some effort is needed to bring deep space >exploration down to the $10-50 million/probe range that universities, >corporations, and other non-government organizations might consider. >The major R&D items needed: > >* Microsatellite technology: > -- standard microdevice bus > -- small instruments >* Upper stage for microsatellites >* Pre/post calibration (target switching) and bandwidth upgrades to DSN > to allow coverage of a much larger sky population Also useful would be major reductions in launch costs, else you spend all that $10-50M on the launch and have nothing left over for spacecraft and operations. -- "But this *is* the simplified version | Henry Spencer @ U of Toronto Zoology for the general public." -S. Harris | henry@zoo.toronto.edu utzoo!henry ------------------------------ End of SPACE Digest V13 #205 *******************