Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from beak.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 ; Mon, 7 Jan 1991 01:25:45 -0500 (EST) Message-ID: <8bW1F2200VcJE=Ik5u@andrew.cmu.edu> Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Mon, 7 Jan 1991 01:25:07 -0500 (EST) Subject: SPACE Digest V13 #014 SPACE Digest Volume 13 : Issue 14 Today's Topics: Re: Solar cell factor/Space computers Re: Interstellar Light Sails Re: orbiting Earth in the stratosphere by balloon. Interstellar Light Sails Re: Interstellar travel BRICKS file format Re: Interstellar travel Re: Interstellar travel Re: Interstellar travel Re: Recent Newsstand Magazine Articles Re: Interstellar Light Sails 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 ---------------------------------------------------------------------- Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 30 Dec 90 00:26:31 GMT From: cs.utexas.edu!news-server.csri.toronto.edu!utzoo!henry@tut.cis.ohio-state.edu (Henry Spencer) Organization: U of Toronto Zoology Subject: Re: Solar cell factor/Space computers References: Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu In article 86ftsccq@SACEMNET.AF.MIL ("86FTSCCQ") writes: >1) If I have a solar cell that puts out 0.5a at 6 volts on Earth, > how much power will it produce of the various planets/sattels in > our solar system? Is there a straight forward set of factors ... Look up the distances from the Sun, and remember that the sunlight intensity diminishes as the square of distance. That's all you need, barring possible complications like nonlinear behavior in the cells. (One thing to be careful of is the cell temperature, by the way.) >2) Is it possible to make "spaceable" a regular circuit board.... > such as a embedded computer hardware controller? Depends; what do you mean by "spaceable"? Almost anything that doesn't need convection for cooling can fly in the shuttle cabin -- for example, Radio Shack Model 100s have flown unmodified. If you're talking about use in an unpressurized satellite, you need to worry a little about outgassing in vacuum and a lot about temperature control. For long missions or critical applications, you also need to worry about radiation effects, both gradual degradation due to accumulated dose and transient hiccups due to single particle hits. -- "The average pointer, statistically, |Henry Spencer at U of Toronto Zoology points somewhere in X." -Hugh Redelmeier| henry@zoo.toronto.edu utzoo!henry ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 30 Dec 90 00:41:07 GMT From: cs.utexas.edu!news-server.csri.toronto.edu!utzoo!henry@tut.cis.ohio-state.edu (Henry Spencer) Organization: U of Toronto Zoology Subject: Re: Interstellar Light Sails References: <1990Dec29.212153.20748@cunixf.cc.columbia.edu> Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu In article <1990Dec29.212153.20748@cunixf.cc.columbia.edu> apa1@cunixf.cc.columbia.edu (Andrew Peter Anselmo) writes: >Anybody given any thought in this newsgroup about Robert L. Fowards' >interstellar light sail ships? ... Has this idea >been shot down, and am I basing this idea on fuzzy science-fiction science? Forward generally does his homework; he's not above fudging the details when necessary for story continuity (for example, the neutronic life in Dragon's Egg is not workable), but his lightsails in particular showed up in serious papers before he used them in his fiction. If you can build the laser system on the necessary colossal scale, laser sails are workable. -- "The average pointer, statistically, |Henry Spencer at U of Toronto Zoology points somewhere in X." -Hugh Redelmeier| henry@zoo.toronto.edu utzoo!henry ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 29 Dec 90 00:19:48 GMT From: zaphod.mps.ohio-state.edu!swrinde!mips!news.cs.indiana.edu!msi.umn.edu!cs.umn.edu!kksys!wd0gol!newave!john@tut.cis.ohio-state.edu (John A. Weeks III) Organization: NeWave Communications Ltd, Eden Prairie, MN Subject: Re: orbiting Earth in the stratosphere by balloon. References: <1990Dec27.113908.11149@pbs.org> Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu In article <1990Dec27.113908.11149@pbs.org> pstinson@pbs.org writes: > There was an item in an aerospace magazine last October about a planned > nonstop flight around the world in a high altitude balloon. I have heard about this, too, but I do not recall the starting date. One of the crew and main sponsor is the head of Virgin Records. They made a crossing of the Atlantic Ocean a few years back. -john- -- =============================================================================== John A. Weeks III (612) 942-6969 john@newave.mn.org NeWave Communications ...uunet!rosevax!tcnet!wd0gol!newave!john =============================================================================== ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 29 Dec 90 21:21:53 GMT From: usc!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!cunixf.cc.columbia.edu!apa1@ucsd.edu (Andrew Peter Anselmo) Organization: Columbia University Subject: Interstellar Light Sails Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu Anybody given any thought in this newsgroup about Robert L. Fowards' interstellar light sail ships? They do away with a lot of the nastiness of carrying your own fuel. The basic premise is to use a ring of lasers in orbit around Mercury (powered from the sun) to boost a light sail. I know Doc Foward is a big proponent of light sails; the interstellar light sail concept was in a fiction book of his _Flight of the Dragonfly_. Any comments? Has anybody seen, heard or read about what I'm babbling about? Has this idea been shot down, and am I basing this idea on fuzzy science-fiction science? Thanks. Andrew Peter Anselmo / Department of Mechanical Engineering / 220 SW Mudd Columbia University in the City of New York, New York, NY 10027 (212)-854-2965 BITNET: apa1@cunixf.cc.columbia.edu DECNET: CUMEVA::ANSELMO <<< Independently Owned and Operated >>> ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 30 Dec 90 00:37:15 GMT From: cs.utexas.edu!news-server.csri.toronto.edu!utzoo!henry@tut.cis.ohio-state.edu (Henry Spencer) Organization: U of Toronto Zoology Subject: Re: Interstellar travel References: <3039@mentor.cc.purdue.edu>, <1315@geovision.UUCP>, Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu In article jmc@Gang-of-Four.stanford.edu (John McCarthy) writes: >Here's a method of interstellar travel based entirely on present science >and technology... >The idea is to use an ordinary fission reactor to generate electricity, >and use the electricity to expel a working fluid at an appropriate >velocity... I'm not sure I would call this entirely based on current technology, since it puts very heavy demands on the reactor technology, given the weight constraints. (Any electrical-propulsion system suffers badly on this, in fact, since electricity is a very cumbersome way of handling large amounts of power. A chemical rocket engine the size of a large man has the same useful power output as the very biggest power plants.) However, it's really not terribly difficult to establish John's basic point, that interstellar travel is clearly feasible if travel times of centuries are acceptable. There are too many different methods that should be feasible within the next hundred years or so; it requires a really huge leap of faith to conclude that they are *all* unworkable. -- "The average pointer, statistically, |Henry Spencer at U of Toronto Zoology points somewhere in X." -Hugh Redelmeier| henry@zoo.toronto.edu utzoo!henry ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 30 Dec 90 00:45:55 GMT From: ccncsu!typhoon.atmos.colostate.edu!thorson@boulder.colorado.edu (Bill Thorson) Organization: CSU Dept. of Atmospheric Science Subject: BRICKS file format Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu Is there anyone out there who has ever heard of the BRICKS image file format. I believe it is either created or just used by a company called Intl. Imaging Systems I(2)S. I know this company is using it for satellite images so that may be the primary use for the format. If you know something, please let me know. I would like to get the specs. for this file format. Bill Thorson #!/bin/sh #-----------------------------------------------------------------------# echo Bill Thorson thorson@typhoon.atmos.colostate.edu echo Dept of Atmospheric Science +1 303 491-8339 echo Colorado State University echo Ft. Collins, CO 80523 Cray||Sun||Amiga -- I can't decide? #-----------------------------------------------------------------------# ------------------------------ Date: 29 Dec 90 11:27:42 GMT From: prometheus!pmk@mimsy.umd.edu (Paul M. Koloc) Subject: Re: Interstellar travel In article <1990Dec29.071159.21427@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >In article <3039@mentor.cc.purdue.edu> f3w@mentor.cc.purdue.edu (Mark Gellis) writes: >>...the lack of discussion of fusion drives...I know there are a >>LOT of technical problems involved, but doesn't a mass production >>facility for anti-matter involve just as many problems? >Believe it or not, they actually look to be easier problems. I don't believe it. >Deuterium is almost useless as a fusion fuel for high-performance rockets >because of the fierce neutron emission, which is not just a radiation >hazard but also a very serious heating problem. AND, the destructive heating comes from the hot neutrons. >>... By the way, what would be involved in an anti-matter >>mass production facility, one large enough to provide a large >>civilization with fuel for all its spacecraft? >It depends on how many spacecraft, and how ambitious they are. If you're >willing to start with a large, ambitious program of solar-system exploration >(manned) plus extensive operations in Earth orbit, something the size of >the Hanford nuclear works would do. (That is, it's within the scale of >what has already been done in very-large-scale industrial activity.) Large, ambitious program... ?? Sounds pitifully small to me, and we don't need a miserly energy ration for the ships in such an undertaking. On the other hand, what this planet does NOT need is a few hundreds more Hanfords. So let's get serious with advanced fusion concepts. +---------------------------------------------------------+**********+ | +Commercial* | Paul M. Koloc, President (301) 445-1075 ***FUSION*** | Prometheus II, Ltd.; College Park, MD 20740-0222 ***in the*** | mimsy!prometheus!pmk; pmk@prometheus.UUCP **Nineties** +---------------------------------------------------------************ ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 30 Dec 90 13:35:39 GMT From: zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!dali.cs.montana.edu!milton!byron!hermetic@tut.cis.ohio-state.edu (Joshua Geller) Organization: University of Washington, Seattle Subject: Re: Interstellar travel References: <1990Dec29.153412.12831@cs.rochester.edu>, <1990Dec29.170010.25422@watdragon.waterloo.edu>, <1990Dec30.002828.7156@zoo.toronto.edu> Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu In article <1990Dec30.002828.7156@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >The sheer size needed is a practical obstacle, as are the costs of the >bombs and the legal problems of exploding nuclear bombs in space. But >it is pretty definitely workable, although rather marginal as an >interstellar propulsion system. But (please correct me if I am mistaken) a near ideal interplanetary drive? >-- >"The average pointer, statistically, |Henry Spencer at U of Toronto Zoology >points somewhere in X." -Hugh Redelmeier| henry@zoo.toronto.edu utzoo!henry @*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@ { As any intelligent user should realize,| If I had a steel Q-tip, I would } { my opinions have nothing to do with the| stuff it in my ear, turn on 10,000 } { University of Washington or any group | volts, and channel god. } { of humans or individual human soever. | Spamgod } { ---------------------------------------|----------------------------------- } { Joshua Geller hermetic@byron.u.washington.edu (USmail Seattle, 98102-1752) } @*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@*@ ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 30 Dec 90 22:25:59 GMT From: usc!cs.utexas.edu!news-server.csri.toronto.edu!utzoo!henry@ucsd.edu (Henry Spencer) Organization: U of Toronto Zoology Subject: Re: Interstellar travel References: <1990Dec29.170010.25422@watdragon.waterloo.edu>, <1990Dec30.002828.7156@zoo.toronto.edu>, <13565@milton.u.washin Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu In article <13565@milton.u.washington.edu> hermetic@byron.acs.washington.edu (Joshua Geller) writes: >>[thermonuclear Orion] >>The sheer size needed is a practical obstacle, as are the costs of the >>bombs and the legal problems of exploding nuclear bombs in space. But >>it is pretty definitely workable, although rather marginal as an >>interstellar propulsion system. > >But (please correct me if I am mistaken) a near ideal interplanetary drive? Only if you can build small thermonuclear bombs cheaply, in particular if you can build them without the expensive fission component. Dyson's interstellar Orion ship was the size of Chicago, large enough to make cost-effective use of existing fusion bombs. Orion does not scale down terribly well; apart from the cost angle, the limited information now available on Orion design (it's mostly still classified) strongly suggests that performance drops as the ship shrinks. There is also reason for concern -- not well appreciated at the time -- about the effects of nuclear explosions in space on electronic equipment. If you're using Orion ships within the solar system, and in particular near Earth, you're going to be operating them in relatively close proximity to a lot of sensitive equipment. ("Close" here can mean tens or even hundreds of thousands of kilometers.) Near Earth there is the added complication of charged particles being trapped by the Van Allen belts; the handful of nuclear tests that were run at very high altitudes thirty years ago were very hard on the satellites then in orbit. The best way to build an Orion is to take it to its logical extreme and use fusion microexplosions ignited by particle beams (lasers are probably too heavy for spaceflight applications) and channeled by a magnetic nozzle. This is a bit unsatisfactory because we can't quite build one of those yet, while we could build a more orthodox Orion, but the microexplosion approach is generally a better drive. -- "The average pointer, statistically, |Henry Spencer at U of Toronto Zoology points somewhere in X." -Hugh Redelmeier| henry@zoo.toronto.edu utzoo!henry ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 30 Dec 90 23:39:42 GMT From: haven!uvaarpa!murdoch!faraday.clas.Virginia.EDU!lhb6v@louie.udel.edu (Laura Hayes Burchard) Organization: University of Virginia Subject: Re: Recent Newsstand Magazine Articles References: <4249@mindlink.UUCP> Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu While we're on the subject, I noticed in Time that the New York Times failed in its attempt to get the tapes of the Challenger's final moments released, with NASA arguing that the privacy of the astronauts' families demanded that they be kept secret. I'm curious; have the families actually said this? I recall that in the immediate aftermath, at least one family was attempting to get them released for use in a suit against NASA. I don't particularly want the tapes released, but I'd like to know that there was an honest transcript. -- Laura Burchard lhb6v@virginia.edu lhb6v@virginia.bitnet October 3: After 45 bitter years of separation, East and West Germany unite to form a single nation, chastened by the past, hopeful for the future. October 4: Germany invades Poland. --Dave Barry's Year in Review 1990 ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 30 Dec 90 10:09:33 GMT From: prometheus!pmk@mimsy.umd.edu (Paul M. Koloc) Organization: Prometheus II, Ltd. Subject: Re: Interstellar Light Sails References: <1990Dec29.212153.20748@cunixf.cc.columbia.edu>, <1990Dec30.004107.7363@zoo.toronto.edu> Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu In article <1990Dec30.004107.7363@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >In article <1990Dec29.212153.20748@cunixf.cc.columbia.edu> apa1@cunixf.cc.columbia.edu (Andrew Peter Anselmo) writes: >>Anybody given any thought in this newsgroup about Robert L. Fowards' >>interstellar light sail ships? ... Has this idea >>been shot down, and am I basing this idea on fuzzy science-fiction science? > .. . If you can build the laser system >on the necessary colossal scale, laser sails are workable. Let's look into the future hazards of this approach: A fleet of Sophians were vaporized when they cut through the beam (during a heated debate). After a few decades of flawless performance, the mirror was sabotaged by the Helicons (a tribe of radical solar orbital environmentalists). A ship, The Henry (no relation), strayed just out of the beam, (temporary guidance failure). Beam traffic increased to the point where the system power convertor blew. But what the heck Our highways are cruised by drunk drivers (with/without licenses). +---------------------------------------------------------+**********+ | +Commercial* | Paul M. Koloc, President (301) 445-1075 ***FUSION*** | Prometheus II, Ltd.; College Park, MD 20740-0222 ***in the*** | mimsy!prometheus!pmk; pmk@prometheus.UUCP **Nineties** +---------------------------------------------------------************ ------------------------------ End of SPACE Digest V13 #014 *******************