Subject: Space-tech Digest #87 Contents: William Dee Rieken Final Frontier Magazine, etc Henry Spencer Re: Final Frontier Magazine, etc Peter Scott Re: Final Frontier Magazine, etc Chris Daniel Re: Final Frontier Magazine, etc Paul Dietz Lunar volatiles Phil Fraering About Lunar Ice... Paul Dietz Re: About Lunar Ice... Bill Davidsen Re: Lunar volatiles Phil Fraering Re: About Lunar Ice... Henry Spencer Re: Lunar volatiles Henry Spencer Re: Lunar volatiles ------------------------------------------------------------ Date: Tue, 5 Nov 1991 10:26-EST From: will@rins.ryukoku.ac.jp To: space-tech@cs.cmu.edu Subject: Final Frontier Magazine, etc What do you think of the Final Frontier Magazine. I bought one the other day, looks not to be technical enough for me. Is there anything available that is technical on space related things? Do you know where I may get extreme technical data for the DynaSoar Plane (X-20)? Thankyou very much, William Dee Rieken Researcher, Computer Visualization Faculty of Science and Technology Ryukoku University Seta, Otsu 520-21, Japan Tel: 0775-43-7418(direct) Fax: 0775-43-7749 will@rins.ryukoku.ac.jp ------------------------------ From: henry@zoo.toronto.edu Date: Tue, 5 Nov 91 13:38:19 EST To: space-tech@CS.CMU.EDU Subject: Re: Final Frontier Magazine, etc > What do you think of the Final Frontier Magazine. I bought one the > other day, looks not to be technical enough for me. Is there anything > available that is technical on space related things? ... Final Frontier is probably the best popular magazine on spaceflight, but it definitely doesn't make any great attempt to be technical. One should realize that any technical publication is going to have a much more limited market, implying less glossy production and much higher cost. Apart from the scholarly publications of the AIAA, the AAS, and similar, the one good technical publication I know of about spaceflight is "Planetary Encounter", which has a lot of technical material on planetary exploration. (Its companion, "World Spaceflight News", is mostly shuttle mission plans but does occasionally have interesting content.) Here's a review I wrote of them a few years ago, slightly dated but still mostly right: [Next in the multi-way tie for third place in space-related periodicals is a pair: Planetary Encounter and World Spaceflight News. These are for people who want the nitty-gritty details. No glossy color photos or quotations from Chairman Carl to be found here, just page after page of real hard solid information. PE covers planetary missions, WSN covers near-Earth spaceflight. Aviation Leak spent one paragraph discussing Joe Kerwin's medical report on the deaths of the Challenger crew; WSN printed the whole thing. The NRC report on shuttle flight frequencies etc. got about one column in AW&ST; WSN printed the whole thing. The so-called International Comet Explorer got some polite coverage in various journals (no exciting photos to be had, since it had no camera); PE spent an entire issue on it, with diagrams, lists of experiments, an interview with the mission director, etc. When the shuttle was flying regularly, WSN printed things like payload manifests, activity schedules, and post- mission assessment reports for EVERY mission. The same crew also puts out a succession of extra-cost "special reports", containing things like NASA technical documents on related topics. (Example: although I think they may have had second thoughts due to poor sales on this, at one point they were going to put out a multi-volume special report reprinting the entire Critical Items List from the shuttle.) Highly recommended if you are tired of the babytalk in newsstand magazines and want to know the gory details. PE and WSN are at Box 98, Sewell NJ 08080. Each is nominally monthly, although in fact they've been coming out less frequently for the last year or so due to lack of news. Each is $30 for 12 issues sent First Class to the US or Canada, elsewhere $45 for 12 issues sent Air Mail.] Henry Spencer at U of Toronto Zoology henry@zoo.toronto.edu utzoo!henry ------------------------------ From: pjs@euclid.JPL.NASA.GOV (Peter Scott) Subject: Re: Final Frontier Magazine, etc To: space-tech@CS.CMU.EDU X-Mailer: Poste 1.1 Date: Wed, 6 Nov 91 09:05:10 -0800 Encoding: 8 TEXT, 2 TEXT SIGNATURE > What do you think of the Final Frontier Magazine. I bought one the > other day, looks not to be technical enough for me. Is there anything > available that is technical on space related things? ... FF is very readable and entertaining - a lot like Smithsonian Air & Space. If you're looking for technical research material, try making a donation to Space Studies Institute to get their Update; only a few pages quarterly, but up-to-the-minute stuff on mass drivers and lunar construction research. Peter J. Scott, Member of Technical Staff | pjs@euclid.jpl.nasa.gov Jet Propulsion Laboratory, NASA/Caltech | SPAN: GROUCH::PJS ------------------------------ From: Chris Daniel Date: Wed, 6 Nov 91 23:33:02 -0500 To: space-tech@cs.cmu.edu Subject: Final Frontier magazine About two years ago, I discovered Final Frontier. It really impressed me... I really liked the idea of a Space magazine... and I liked the fact that they followed not only NASA, but also looked into private companies (like AMROC) and also space efforts of other countries. And it was not a news-rag...it is a finely-finished product. Lots of full-color glossy pictures. Good articles, both on current efforts, and the 'artsy' side of space... what the 'visionaries' (read: pipe-dreamers) think might happen w/ space in the future. I was so impressed, poor starving college student that I am, that I took them up on their long-term subscription... mine's thru Feb. 2002. It's true... if you're expecting blueprints and dimensions and pages of orbital calculations and that sort of nonsense, this isn't what you're looking for. But, like someone mentioned...it's like Air&Space. But, I don't care for the air part... so I never really cared for Air and Space, only picking up an issue if it had something that caught my eye. And my collection of back issues is *nearly* complete... I'm dying to find the last missing issue... June/July 1988, their 2nd issue (I found the 1st issue!) If anyone has it, and willing to part with it for $$$, lemme know! There it is, my opinion, anyways. YMMV. -Chris Daniel ------------------------------ Date: Mon, 18 Nov 91 20:55:17 EST From: dietz@cs.rochester.edu To: space-tech@cs.cmu.edu Subject: Lunar volatiles There was a short discussion on sci.space about the ever-popular lunar polar ice question. The question arises: how would one get the lunar ice off? Mass drivers were suggested, but these tend to be large and need power in short bursts (which would require massive power conditioning equipment). More likely, and more obviously, early ice shipments would be by rocket, with material derived from the ice used as reaction mass. What fuel should the rockets use? The ice on the moon, if a product of lunar impact of volatile-rich objects, is likely contaminated with a wide range of impurities, including hydrocarbons, alcohols, clathrates of various kinds, sulfurous compounds, halogenated compounds, and so on. So, any ice processing system is going to have to be able to purify the resulting water. However, some of the compounds may be useful. If only water is to be used, it can be decomposed to hydrogen and oxygen by electrolysis. However, one would have to be careful that that no impurities got into the water to poison the electrodes of the electrolysis cell. A possible solution would be to use a high temperature electrolysis system, based on solid oxide electrolytes. This would have two advantages: (1) the electrodes would not require electrocatalysts, and would be less succeptible to contamination, and (2) by operating at high temperature (1000 C), the cells would require less electrical energy to produce a given amount of hydrogen and oxygen (the excess energy coming out of the heat), thereby using some of the heat energy that would otherwise be discarded out the radiator. This reduces the size of the power system. Oxygen (or an oxygenated compound, like N2O4) is just about the only choice for an oxidizer. For a fuel, there could be many choices, even if we are restricted to liquids: (1) Hydrogen. Hydrogen offers high Isp, but is bulky, and is difficult to liquify. However, if the vehicles being used to transport fuel off the moon are SSXs or SSX-derived vehicles, it would be compatible. (2) Hydrocarbons or other volatiles separated from the ice. Ice might contain methane clathrate, for example. Gentle heating melts it, releasing the methane. These would still have to be used with oxygen from electrolysis, but the combustion of oxygen and hydrocarbons releases more energy, per mole of oxygen, than combustion of hydrogen and oxygen (at lower Isp, granted). (3) Organic compounds can be reformed with steam to produce hydrogen (as can metallic iron, derived from regolith by magnetic rake). This offers a lower-energy way of producing hydrogen for export than electrolysis. (4) Organic compounds, heated with steam, form synthesis gas. Synthesis gas can be subject to the Fischer-Tropsch reaction to make higher hydrocarbons. I understand meteoric metals can act as FT catalysts; perhaps a catalysts bed can be prepared by simply raking up the magnetic particles from the regolith and depositing them, after a bit of sintering, in a reaction vessel. Electrolysis can be avoided entirely if nuclear thermal rockets are used to launch from the moon. The fuel then could be simply water (or the CO2 waste from the steam reforming process); hydrogen could be produced by thermochemical reactions as described above for use in high-Isp thermal rockets in space. Paul F. Dietz dietz@cs.rochester.edu ------------------------------ Date: Mon, 18 Nov 1991 22:09:21 -0600 From: Fraering Philip G To: space-tech@cs.cmu.edu Subject: About Lunar Ice... Actually, keep in mind that in the simplifying case that this is water ice, some 85 or so percent of it by weight is oxygen... it would be foolish to separate out the hydrogen for use in an electric rocket as Paul Dietz suggests and then to ignore the oxygen. I have one very good reference on this, but I would like more: it is possible to use oxygen as fuel for an ion drive system. Somewhere on the stack of papers on my desk is a paper on an ion generator that is capable of ionizing corrosive gases such as oxygen... oh, here it is: "30 -cm Electron Cyclotron Plasma Generator," Hank Goude, TRW Space and Technology Group, Redondo Beach, Ca. in Vol 24, No. 5, Sept-Oct 1987 Journal of Spacecraft and Rockets (oops, it's too late for me to go back and underline it properly)... I have tried calling him at Redondo Beach TRW Space and Technology Group, but apparently he doesn't work there now. Anyway, it can apparently (at least according to the theory) generate a plasma without the severe problems of electrode erosion found even in noble gases... Anyway, that generator could be the basis for an electric rocket using oxygen. Which means that you might even be able to ship the water around by rocket using no hydrogen except for the short fast thrust needed at takeoff, and using mainly the lunar oxygen that a well extablished base would have more of than they know what to do with. Of course, if you find any problems with the above scenario, let me know. I am rather fallible :-) Also, if anyone knows where I could find Dr. Goude right now, please let me know, ok? Phil Fraering pgwres01@ucs.usl.edu ------------------------------ Date: Tue, 19 Nov 91 06:54:37 EST From: dietz@cs.rochester.edu To: pgwres01@ucs.usl.edu Subject: Re: About Lunar Ice... Cc: space-tech@cs.cmu.edu Phil said it would be foolish to separate out hydrogen for use in an electric rocket. This is quite correct, but I didn't say that! I said separate out the hydrogen for use in a *thermal* (nuclear or solar) rocket. In that kind of rocket, Isp depends on the molecular weight of the reaction mass. Paul ------------------------------ Reply-To: davidsen@crdos1.crd.ge.com Date: Tue, 19 Nov 91 09:56:19 EST X-Mailer: Mail User's Shell (6.5 4/17/89) From: davidsen@crdos1.crd.ge.com To: space-tech@cs.cmu.edu Subject: Re: Lunar volatiles One thought comes to mind for lunar launch: since the object is volitiles anyway, could a variable focal length parabolic mirror and all that free solar energy be used to provide a steam powered rocket? The performance of a system powered from the ground (or orbit, whatever) is going to be pretty good, and you can probably use any volatile you find as "fuel." If you have a computer on the engine to control the direction and send info back to the mirror, and another at the mirror to keep the focus close, you should be able to get the control lag under control and keep the focus nominal. After launch the motor could retrofire back to the surface. Envision a motor consisting of a nozzle and heating chamber (to be heated by a mirror). Crushed volatiles are fed in by a piston, giving some crude throttle. I suspect the nozzle end would need to be gimboled to steer. In crushing the volatiles any rocks large enough to seriously erode the nozzle could be removed, and there are probably enough ceramic base materials on the moon to make the nozzles cheap. My question is, are there enough volatiles on the moon to use for a water supply, or should they be used for launch reactive mass to orbit something more useful? I don't have anything in mind, I'm just wondering if this is a good resource to consume, particularly since any long term habitation would need water of it's own. As far as doing an H2/LOX system based on volatiles, it would seem that for low volume production you could build a pretty good heat pump using blackbody radiation to space as the "hot" end. This would be useful for a 2nd stage after the steam power got the payload close to orbit. ------------------------------ Date: Tue, 19 Nov 1991 09:32:10 -0600 From: Fraering Philip G To: dietz@cs.rochester.edu, pgwres01@ucs.usl.edu Subject: Re: About Lunar Ice... Cc: space-tech@cs.cmu.edu Funny you should propose that; I have a paper right here about comet resource utilization where Dr. Anthony Zuppero of INEL talks about how using the water straight in a nuclear thermal rocket is better than breaking it up into H and O and using the H... Of course: 1. This is a rough 'working draft' of the paper, and 2. I do not agree (or disagree) with his conclusions at the moment; I intend to to a lot of work on evaluating this over the next two or three months. Phil ------------------------------ From: henry@zoo.toronto.edu Date: Tue, 19 Nov 91 11:21:25 EST To: space-tech@cs.cmu.edu Subject: Re: Lunar volatiles >Electrolysis can be avoided entirely if nuclear thermal rockets are >used to launch from the moon. The fuel then could be simply water (or >the CO2 waste from the steam reforming process)... Note, however, a nasty design complication: both water and CO2 become oxidizing agents at high temperatures, which presents materials problems for a nuclear-thermal rocket. Hydrogen or hydrocarbons are better here too. Henry Spencer at U of Toronto Zoology henry@zoo.toronto.edu utzoo!henry ------------------------------ From: henry@zoo.toronto.edu Date: Tue, 19 Nov 91 11:30:31 EST To: space-tech@cs.cmu.edu Subject: Re: Lunar volatiles > If you have a computer on the engine to control the direction and send >info back to the mirror, and another at the mirror to keep the focus >close, you should be able to get the control lag under control and keep >the focus nominal... You might have to work at relatively high acceleration to make this go. Bear in mind that the Sun is not a point source; practical focusing distances will be considerably shorter than for a laser. Unfortunately, that worsens the window problem -- it's hard to make a chamber window that is mechanically strong at high temperature while also being highly transparent -- by requiring a high-pressure engine. The folks pursuing such things for laser propulsion generally seem to prefer low-pressure chambers to keep the materials problems within bounds. Their work would be relevant, though. (Aiming the beam up the nozzle avoids the window problem, but creates new problems of being able to thrust only along the beam axis and having to keep a beam in focus through the exhaust plume.) > My question is, are there enough volatiles on the moon to use for a >water supply, or should they be used for launch reactive mass to orbit >something more useful? I don't have anything in mind, I'm just wondering >if this is a good resource to consume, particularly since any long term >habitation would need water of it's own. That's the $64G question. Nobody knows. Polar volatiles could be abundant or scarce; the estimates range all over the map. Solar-wind volatiles in the regolith are definitely scarce to the point where you don't want to throw them away. Henry Spencer at U of Toronto Zoology henry@zoo.toronto.edu utzoo!henry ------------------------------ End of Space-tech Digest #87 *******************