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, 11 Apr 89 05:17:34 -0400 (EDT) Message-ID: <0YEQ-Yy00UkZINgk47@andrew.cmu.edu> Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Tue, 11 Apr 89 05:17:25 -0400 (EDT) Subject: SPACE Digest V9 #358 SPACE Digest Volume 9 : Issue 358 Today's Topics: Re: Building a fusion-based rocket Re: Fusion Re: Information needed Rockefeller reference Re: Building a fusion-based rocket aborts and non-aborts Creating Palladium by fusion? Re: DSN mission launch dates Re: NASA tank reuse fiasco Re: Asteroids and Pd fusion Re: alien contact ---------------------------------------------------------------------- Date: 8 Apr 89 21:34:31 GMT From: mailrus!jarvis.csri.toronto.edu!utgpu!utzoo!henry@husc6.harvard.edu (Henry Spencer) Subject: Re: Building a fusion-based rocket In article <943@psueea.UUCP> sandym@psu-cs.cs.pdx.edu (Sandy Michael) writes: >Why on Earth do you want a fusion powered _rocket_? Sounds like a total >waste of energy. ;*) > >How about a fusion powered electricity generator powering an ion drive!!! That's a fusion-powered rocket too; you're confusing definitions. Bear in mind that your generator will have an efficiency of about 30-40% at best. It's not clear which is best. >... Depending on the size of the tanks to payload ratio >you could get into some relativistic effects even. Maybe .1 c if you're >cheap with the deuterium. For probes with light payload you might get >some stuff to the nearer stars by 2100. Not with ion rockets. Please do the arithmetic before suggesting this. Ion rockets simply don't have a high enough exhaust velocity, at least with current ion-rocket technology. >What technology do you see the Earth having by the year 3000? Thoroughly impossible to predict. 2100 is bad enough. (There are people still alive today who remember a time when man could not fly and radio did not exist.) -- Welcome to Mars! Your | Henry Spencer at U of Toronto Zoology passport and visa, comrade? | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: Sat, 8 Apr 1989 11:41-EDT From: Dale.Amon@H.GP.CS.CMU.EDU Subject: Re: Fusion George: The trouble I see with the mono-atomic H idea is that there is no "excess energy". The Palladium electrode is merely a storage device that stores a portion of the input energy used in the electrolysis, and then releases it quickly. Keep in mind that Fleischman and Pons are claiming significantly LARGER output than input after the charging period. I don't think your idea explains the energy output, although it may explain the shutdown problem. If you are correct, you should be able to run the same experiment with plain water and get the same result, sans energy EXCESS. ------------------------------ Date: 8 Apr 89 19:20:04 GMT From: blake!wiml@beaver.cs.washington.edu (William Lewis) Subject: Re: Information needed In article <607977617.amon@H.GP.CS.CMU.EDU> Dale.Amon@H.GP.CS.CMU.EDU writes: >I and a coauthor are nearing the end of draft 2 of a rather large SF >novel (10 years in the making), and I need a few pieces of information. >What would be the appearance of the plume from an antimatter rocket >using Hydrogen? I would presume the Hydrogen comes out the nozzle as a >plasma of protons and electrons that gradually recombine and give off >EM. >Can anyone describe the appearance of such a plume? An "antimatter rocket"? By that, do you mean a rocket using only antimatter (hydrogen & antihydrogen) or a more conventional rocket using antimatter as a power source and hydrogen as the reaction mass? If the former, there would be no 'plume'; the exhaust would consist only of high energy photons. (These might make interesting effects in an atmosphere ... such as irradiating a significant portion of a planet ...) If the latter, the plume cold be anything, although I wold gess (%$ my yoo key is broken) that the hotter the plme (IE, plasma) the more efficient the rocket. =-=-=--* Disclaimer: I know nothing. ------------------------------ Date: Sat, 8 Apr 1989 11:52-EDT From: Dale.Amon@H.GP.CS.CMU.EDU Subject: Rockefeller reference Some days back I posted that the Standard Oil "scandal" may not actually have been fact. For those interested, I have found a reference. John McGee, "Predatory Price Cutting: The Standard Oil (N.J.) Case," in The Competitive Economy: Selected Readings, ed. Yale Brozen (Morristown, N.J.: General Learning Press, 1975). p. 403. "Judging from the Record, Standard Oil did not use predatory price discrimination to drive out competing refiners, nor did its pricing practive have that effect... I am convinced that Standard Oil did not systematically, if ever, use local price cutting in retailing, or anywhere else, to reduce competition. To do so would have been foolish; and, whatever else has been said about it, the old Standard organization was seldom criticized for making less money when it could readily have made more." ------------------------------ Date: 8 Apr 89 21:29:19 GMT From: phoenix!kpmancus@princeton.edu (Keith P. Mancus) Subject: Re: Building a fusion-based rocket In article <943@psueea.UUCP> sandym@psu-cs.cs.pdx.edu (Sandy Michael) writes: > >Why on Earth do you want a fusion powered _rocket_? Sounds like a total >waste of energy. ;*) > >How about a fusion powered electricity generator powering an ion drive!!! > >mehawk@reed.uucp Because we don't have the capability to put big payloads into orbit cheaply. You'll never be able to do that with an ion drive. While deep space missions are useful, the urgent need NOW is Real Cheap missions to LEO and GEO. I realize that flying nuclear-powered rockets in the atmosphere is tricky. The heat exchanger has to be very permeable to heat while blocking any significant (nuclear) radiation from getting to the reaction mass. But the idea isn't mine; Eugene Sanger discusses both convective fission rockets and nuclear hypersonic ramjets in _Space Flight_ (an excellent read). He shows that for a nuclear (fission) powered rocket launching from Earth, the payload is approximately 20% of the takeoff weight. (Note that it has been ~10 years since I read this book, so please excuse me if I'm garbling his arguments.) The spaceplane is more practical if it is based on a nuclear engine (this is also discussed in _Space Flight_). The higher Isp you can get from a nuclear engine (corresponding to exhaust velocities of approximately 10-12 km/sec in vacuum) makes these vehicles considerable more efficient. I've been playing around with these ideas for the past 4 years. Lots of back-of-the-envelope stuff. Now if Third Millenium Inc. just gets their funding soon (they're interested in hiring me)..... Feel free to send mail if you want to discuss this. -KPM -- ------------------------------------------------------------------ -Keith Mancus <- preferred ------------------------------ Date: 8 Apr 89 21:08:25 GMT From: mailrus!jarvis.csri.toronto.edu!utgpu!utzoo!henry@husc6.harvard.edu (Henry Spencer) Subject: aborts and non-aborts In article <467@atlas.tegra.UUCP> vail@tegra.UUCP (Johnathan Vail) writes: >Another tense time was when they almost aborted to Spain when it >looked like some kind of valve in the main engines was bad... It was temperature sensors going bad, actually. This sort of false common failure (affecting all engines) is particularly nasty because there are times during climb when a multiple engine failure is unsurvivable. Actually, if you want an example of a controller coolly overriding failing hardware, consider the incident during the Saturn I program when something appeared to go wrong shortly before launch and the launch was scrubbed as per the rules... only to have Kurt Debus, who knew the hardware pretty well, override the scrub and order the launch to proceed! It did; perfect flight. (For those who don't know the name, Debus was one of Von Braun's old crew and was head of KSC during Apollo.) -- Welcome to Mars! Your | Henry Spencer at U of Toronto Zoology passport and visa, comrade? | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 8 Apr 89 17:46:30 GMT From: ogccse!blake!wiml@husc6.harvard.edu (William Lewis) Subject: Creating Palladium by fusion? I doubt it is possible to do any sort of fusion beyond, maybe, Lithium using this new palladium method ... the hydrogen [deuterium] has to diffuse into the palladium electrode, from what I hear, and it might be difficult to get the palladium to diffuse out =8) ---- Tagline-less ... ------------------------------ Date: 8 Apr 89 17:54:15 GMT From: mailrus!jarvis.csri.toronto.edu!ois.db.toronto.edu!hogg@purdue.edu (John Hogg) Subject: Re: DSN mission launch dates In article <408@cbnewsl.ATT.COM> sw@cbnewsl.ATT.COM (Stuart Warmink) writes: >"Ariadne" is the (pseudo-) collumnist in "New Scientist". You probably mean >"Ariane", I hope! Well, the latter is just the French translation of the former. Hats off to ESA for coming up with the name. Has there been any other in the history of space exploration that was half so fitting? -- John Hogg hogg@csri.utoronto.ca Department of Computer Science, University of Toronto ------------------------------ Date: 8 Apr 89 21:23:53 GMT From: mailrus!jarvis.csri.toronto.edu!utgpu!utzoo!henry@husc6.harvard.edu (Henry Spencer) Subject: Re: NASA tank reuse fiasco In article <10316@nsc.nsc.com> andrew@nsc.nsc.com (andrew) writes: >I was horrified to read that more than $8B has already been junked by >discarded fuel tanks; about $300M per tank... >Wouldn't it be so nice just to attach a parasitic mini-thruster and >control system to all tanks, just to go that last ten yards? As has been mentioned a number of times in the past (sigh), it is not that simple. Tanks left to themselves in orbit will not stay there for long -- they are too big and too light, air drag will bring them down. Keeping them up is not a trivial problem, especially if you insist on using only fully-proven technology (which is considered a requirement when the risks include dropping many tons of metal on a city somewhere). If you *do* manage to get them to stay up, the insulation on them will "popcorn" in vacuum, adding considerably to the space-debris problem. Taking the tank up into orbit is not free with trajectories used nowadays. Finally, space debris has a good chance of puncturing the tanks before too very long, so you have to protect them if you want them to stay intact. All these things can be solved, but the solutions cost money and add weight, and it is difficult to show specific *short-term* benefits to justify this. (Congress essentially refuses to take a long-term view of anything involving money.) -- Welcome to Mars! Your | Henry Spencer at U of Toronto Zoology passport and visa, comrade? | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 9 Apr 89 03:01:13 GMT From: nsc!andrew@decwrl.dec.com (andrew) Subject: Re: Asteroids and Pd fusion In article <1989Apr8.212905.131@utzoo.uucp>, henry@utzoo.uucp (Henry Spencer) writes: > In article <10346@nsc.nsc.com> andrew@nsc.nsc.com (andrew) writes: > >... The existence of a heatsink at 3 degK should be a great help for > >the engine design... > > Not as much as you think. Getting the heat out to that heatsink is > *not* a trivial problem. The shuttle uses the entire inner surface of > its payload-bay doors as a heat radiator. If you look at pictures of > the space station, you'll see two sets of big flat panels sticking > out -- solar panels, and radiators. Fusion rockets are likely to have > quite serious cooling problems, at least in high-performance versions. Thanks - I didn't know that. Since we're talking about interplanetary travel, the convential cylinder is about the dumbest design then (except the sphere). Maybe we'll see "flatfish" formed from a triple laminate, whereby the outer layers reflect off sun energy and provide shadow for the inner heatsink surface. This design only works well if the outer layers are capable of continuous movement, else the effective heatsink temperature would increase. This is just off the top of my head. ===== Andrew Palfreyman USENET: ...{this biomass}!nsc!logic!andrew National Semiconductor M/S D3969, 2900 Semiconductor Dr., PO Box 58090, Santa Clara, CA 95052-8090 ; 408-721-4788 there's many a slip 'twixt cup and lip ------------------------------ Date: 10 Apr 89 01:38:49 GMT From: mailrus!jarvis.csri.toronto.edu!utgpu!utzoo!henry@csd4.milw.wisc.edu (Henry Spencer) Subject: Re: alien contact In article <7810@pyr.gatech.EDU> ccoprmd@pyr.UUCP (Matthew T. DeLuca) writes: >>Yup, clearly the people who can fly an entirely unmanned shuttle mission >>with a crosswind landing and a launch in freezing weather, perfectly, >>the first time, are ahead on quality. Same conclusion -- they'll go to >>Baikonur. >> >An unmanned shuttle landing...does this impress you, Henry? ... In a crosswind greater than anything the US shuttle has ever dared try, landing within a few feet of the runway center line, yes it does impress me. >I will grant, however, that the Soviets have no real problem with cold weather >launches. Working from Florida, we never had to develop this capability... Correction: the US *thought* it never had to develop this capability. >> [space stations] >You might be right, here. Of course, in five or six years, assuming no >development problems and no erosion of political will, the tables will be >turned... Except by that time, the Soviets will be getting ready to launch Novy Mir, which will re-turn the tables. At the current rate of progress in the US, it may even come first. As for "no development problems", note that the Hubble telescope had a lot of difficulties because it had two "prime" contractors, with NASA trying to do the coordination between them. The space station has *four*. >... I'll put our planetary >exploration program up against the Russians any day. Who has sent the only >successful probes to Mars? Who has sent the only probes *period* to >Mercury? Jupiter? Saturn? Uranus? And coming this August, Neptune? For >that matter, who has sent the only manned missions to another celestial >body? ... The US, decades ago, before it lost interest. If we're discussing history rather than current abilities, we might ask who launched the first Earth satellite, the first man in orbit, and the first man-made objects to reach the surfaces of the Moon, Mars, and Venus. >... Assuming nothing goes wrong (fingers crossed), we'll be sending >new probes out to Venus, to get the highest quality maps of that planet ever, Do remember that the highest-resolution maps of Venus existing right now came from Soviet missions. This is another catchup mission. >... these aren't just paper dreams; Magellan is ready to go, within >the month, and Galileo is just waiting for the launch window. Before being too impressed by this, look up when those projects were started (long ago), when they were originally supposed to be launched (long ago), and how many other projects of that magnitude are in the pipeline (none). >>Or by people who can build launchers that can go up on schedule twice a >>week, year after year, against people who can't seem to launch anything >>on schedule. >> >There's a difference between sending unmanned missions up on schedule and >sending manned missions up... Oh, agreed. The Soviets do both better. >We launch our unmanned missions on schedule just fine. Really? The USAF thinks it will be doing well in 1989 if it manages to launch 70% of the payloads it had hoped to launch this year. >>Welcome to Mars! Your | Henry Spencer at U of Toronto Zoology >>passport and visa, comrade? | uunet!attcan!utzoo!henry henry@zoo.toronto.edu >^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ >How are they going to ask for passports and visas? They can't even get the >customs station to work properly! They'll have plenty of time to try again before they start allowing foreigners to visit. -- Welcome to Mars! Your | Henry Spencer at U of Toronto Zoology passport and visa, comrade? | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ End of SPACE Digest V9 #358 *******************