Date: Mon, 21 Nov 1988 15:56-EST From: space-tech-request@cs.cmu.edu To: "~/st/lists/stdigest" Subject: Space-tech Digest #15 Contents: Paul Dietz Public Domain Orbital Mechanics Routines Paul Dietz Asteroidal Hydrogen Roger Arnold Re: Asteroidal Hydrogen Paul Dietz Re: Asteroidal Hydrogen Mark Purtill Orbital Mechanics Books Paul Dietz Orbital Elements? Roger Arnold RE: Solar Dynamic Power Tom McReynolds RE: Solar Dynamic Power ------------------------------------------------------------ [ Paul Dietz posted his public domain orbital mechanics routines (1700 lines). Send mail to space-tech-request@cs.cmu.edu if you want them. -- Marc ] ------------------------------ Date: Tue, 15 Nov 88 10:19:17 EST From: dietz@cs.rochester.edu To: space-tech@cs.cmu.edu Subject: Asteroidal Hydrogen Carbonaceous asteroids are a potential source of water. However, we want hydrogen for high performance thermal rockets. One could make hydrogen from water by electrolysis. This requires expensive electrical equipment. A better idea might be to exploit the presence of organic materials in class C asteroids. Reduced carbon compounds will react with steam at high temperature to form a mixture of carbon monoxide/dioxide and hydrogen. The CO2 could be dumped, and the hydrogen liquified and stored. With sufficiently clever design to recover waste heat, this is is probably easier than electrolysis. Paul F. Dietz dietz@cs.rochester.edu ------------------------------ From: telesoft!roger@ucsd.edu (Roger Arnold @prodigal) Date: Wed, 16 Nov 88 11:00:41 PST To: space-tech@cs.cmu.edu, dietz@cs.rochester.edu Subject: Re: Asteroidal Hydrogen > [..] However, we want > hydrogen for high performance thermal rockets. [..] > [..] Reduced carbon compounds will react with steam > at high temperature to form a mixture of carbon monoxide/dioxide > and hydrogen. The CO2 could be dumped, [..] ^^^^^^ NO! > Paul F. Dietz > dietz@cs.rochester.edu You never want to simply dump any material that can be used as reaction mass. For a given input power and a given reaction mass, you get more impulse (thrust over time) by expelling all the mass at the same velocity, vs. dumping part of the mass and expelling what's left at a higher velocity. One of the attractions of a mass driver reaction engine is that it doesn't care about what kind of mass it expells. For a solar thermal engine, you obviously can't use rock as reaction mass, but a bit of CO and CO2 mixed in with the H2 is no problem. - Roger Arnold ..ucsd!telesoft!roger ------------------------------ Date: Wed, 16 Nov 88 16:24:17 EST From: dietz@cs.rochester.edu To: telesoft!roger@ucsd.edu Cc: space-tech@cs.cmu.edu,dietz@cs.rochester.edu Subject: Asteroidal Hydrogen I was thinking that making a thermal engine designed for use with hydrogen also operate on CO/CO2/H2 mixtures would add complexity. Perhaps it is worth it. You'd want to vary the gas composition so the average molecular weight decreases with time, I think. Carbon monoxide is also useful in processing metals found in other kinds of asteroids. One can also further react H2 and CO to make storable compounds, like methyl alcohol. Paul F. Dietz dietz@cs.rochester.edu ------------------------------ Date: Tue, 15 Nov 88 16:29:16 EST From: purtill@math.mit.edu To: space-tech@cs.cmu.edu Subject: Orbital Mechanics Books Here are the three messages I got on orbital mechanics books. Thanks to Kevin B. Kenny, Paul F. Dietz and Jenine Abarbanel for the information; I'm starting to look thru some of these books. ----- From: kenny@m.cs.uiuc.edu (Kevin B. Kenny [the Arch-Traitor]) There are a few really good books on the mechanics of artificial satellites. Roy, Archie E. _Orbital motion._ New York and London: Wiley, 1978. ISBN 0-470-99251-4. This is probably the closest to what you're looking for, with a reasonably good coverage of interplanetary transfer orbits and the like. The mathematical content is at the level of a typical graduate course on classical mechanics -- to get useful material out of it, be prepared to do some slogging through Hamiltonians and the calculus of variations. Escobal, Pedro Ramon. _Methods of orbit determination._ New York: Wiley, 1965. No ISBN. This book is not as up-to-date technically as Roy, but has some material on transfer orbits. The discussion of lunar orbits is to be avoided, as it comes from before the discovery of mascons. The sections on analytics of Keplerian motion are invaluable, and duplicated in no other source that I've found. DON'T use his solution to quartic equations or his method of calculating time of eclipse; they have some pretty severe problems with numerical stability. I can send you better ones. Meeus, Jean [Jan]. _Astronomical formulae for calculators._ 2nd ed. Richmond, Virginia: Willmann-Bell, 1982. Here's where you get the description of how to program such things as planetary positions. This little book is *the* classic reference for that. Escobal, Pedro Ramon. _Fundamentals of Astrodynamics._ New York: Wiley, (dammit, I seem not to have written down the year). Treats celestial mechanics from the point of view of spacecraft navigation. The orbital motion material isn't treated as deeply as in Roy. Moulton, Forrest Ray. _An introduction to celestial mechanics._ New York: Macmillan, 1914. A classic. All the citations go back to this. For objects in cislunar space (including LEO and GEO), you'll want to get the basic references on the NORAD prediction models; for this, you start with Hoots, Felix R., and Ronald L. Roehrich. _Models for propagation of NORAD element sets._ Project SpaceTrack Report No. 3, Peterson AFB. Allegedly available from NTIS; if you manage to locate a copy, I want it, as my copy (received electronically) is missing most of the math. The bibliography is quite good, although a fair number of the papers in it are hard to find. ----- From: dietz@cs.rochester.edu Subject: Re: Orbital mechanics book I like "Fundamentals of Astrodynamics" by Bate, Mueller and White (Dover, 1971, paperback, 455 pages, $7.95, ISBN 0-486-60061-0.) I picked up my copy in a B. Dalton bookstore; you can probably order it by mail from Dover. It doesn't have any program listings, but is pretty "cookbook". Paul F. Dietz dietz@cs.rochester.edu ----- From: jenine%priam.usc.edu@oberon.usc.edu (Jenine Abarbanel) Subject: Re: Orbital mechanics book hi! i took an orbital mechanics class last semester. our text book was "fundamentals of astrodynamics" by R. R. Bate, D. D. Mueller and J. E. White. published by dover books, isbn 0-486-60061-0. $7.95. the bible of orbital mechanics. no computer algorithms, but it's a great as a reference book. i hope this helps! and if you feel like bouncing problems off of someone, please write to me, i loved the subject and would like to do more with it. jenine ----- ^.-.^ Mark Purtill purtill@math.mit.edu (617)623-6238 - H ((")) Dept. of Math, MIT 2-229, Cambridge, MA 02139 (617)253-1589 - O ------------------------------ Date: Thu, 17 Nov 88 14:41:05 EST From: dietz@cs.rochester.edu To: space-tech@cs.cmu.edu Subject: Orbital Elements I would like to know if anyone has a machine readable set of orbital elements for the planets and known asteroids, especially earth approaching asteroids. Paul F. Dietz dietz@cs.rochester.edu ------------------------------ From: telesoft!roger@ucsd.edu (Roger Arnold @prodigal) Date: Mon, 21 Nov 88 09:25:33 PST To: space-tech@cs.cmu.edu Subject: RE: Solar Dynamic Power Requested description of solar thermal rocket engine inspired by gaseous core nuclear rocket: In a gaseous core nuclear rocket, the fuel is very high temperature uranium or plutonium vapor that mixes with the hydrogen reaction mass in the equivalent of a combustion chamber--the reactor core. The central problem in a gaseous core nuclear is how to get the heated hydrogen out of the chamber for expulsion as rocket exhaust, while retaining the nuclear fuel inside. The solution is to inject the hydrogen into the chamber through a set of nozzles that set up a matrix of meshing vortices. On the central axis of each vortex is a small exit nozzle. Each vortex is a micro tornado; it spins so fast that the heavy atoms of the nuclear fuel are centrifugally separated from the hydrogen. Only hydrogen is able to make it to the inside of the vortex where it can escape through the exit nozzle. The nuclear fuel ends up largely confined to a set of spinning cylindrical regions through which cold hydrogen flows, gets heated, and flows on to the exit nozzles. For a solar thermal rocket, substitute a heavy element that vaporizes at a lower temperature--say mercury. You might be able to use a fine powder or liquid sol, which would make the centrifugal separation much easier. However, agglomeration of the particles might be a problem. In any case, the purpose of the particles or the heavy ions is to absorb solar radiation and transfer energy to the working fluid that they are migrating through. In effect, you are creating an extremely light and efficient heat exchanger. I've no idea what the practical problems of building a solar thermal rocket along these lines would be. One thing that would _not_ be a problem: the windows and the chamber walls can remain cool. It's only the spinning regions of particles or metal ions, and the gas that has passed through them that are hot. A working temperature of 3500 K is probably feasible. Anyone care to translate that into ISP for hydrogen? (Extra bonus points if you correctly account for dissociation of H2 to monatomic hydrogen at that temperature and its partial recombination to H2 in the exhaust. And I'd like a copy of your computer program). - Roger Arnold ..ucsd.edu!telesoft!roger ------------------------------ Date: Mon, 21 Nov 88 11:16:15 PST From: bohica@Sun.COM (Tom McReynolds) To: space-tech@cs.cmu.edu, telesoft!roger@ucsd.edu Subject: RE: Solar Dynamic Power I'd like to find out more on the Gaseous Core Nuclear Rocket. Do you have references? -Tom ------------------------------ End of Space-tech Digest #15 *******************