Date: Mon, 4 Jan 93 05:04:47 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #629 To: Space Digest Readers Precedence: bulk Space Digest Mon, 4 Jan 93 Volume 15 : Issue 629 Today's Topics: *** BUSSARD RAMSCOOP *** Aluminum as rocket fuel (2 msgs) Aluminum as Rocket Fuel? DC cost estimates DC spacecraft capabilities. (2 msgs) DC vs. Shuttle capabilities Justification for the Space Program Media and space (2 msgs) Moon Dust For Sale Saturn lift capabilities Shuttle a research tool (was: Re: Let's be more specific) Space List Flame Wars Welcome to the Space Digest!! Please send your messages to "space@isu.isunet.edu", and (un)subscription requests of the form "Subscribe Space " to one of these addresses: listserv@uga (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle (THENET), or space-REQUEST@isu.isunet.edu (Internet). ---------------------------------------------------------------------- Date: 3 Jan 93 15:36:30 GMT From: Jason Cooper Subject: *** BUSSARD RAMSCOOP *** Newsgroups: sci.space > Not good enough, alas. The pressure at the *center of the Sun* produces > only the most sluggish hydrogen reaction -- one that will take billions > of years to consume the Sun's hydrogen supply. > > Ordinary hydrogen burns quickly in thermonuclear reactions only under > near-supernova conditions. The heavier isotopes used in fusion bombs > burn like gasoline by comparison, to the point where they are distinctly > rare in the universe -- even the small supply existing on Earth requires > significant effort to explain. > > Building the ramscoop itself is the easy part (difficult though it is). > Getting the hydrogen to *do* something useful, once collected, is hard. > Using it as reaction mass for an antimatter-powered jet engine is going > to be much easier than trying to burn it raw. > -- > "God willing... we shall return." | Henry Spencer @ U of Toronto Zoolog > -Gene Cernan, the Moon, Dec 1972 | henry@zoo.toronto.edu utzoo!henry Ah, but that would defeat the entire purpose of the ramjet itself! You are now carrying around a mass of fuel equal to what you are going to tak in in the scoop. Now we get into all of the standard limitations, as the faster you want to go, the heavier the ship's going to get, the more fuel you'll have to carry, the heavier the ship's going to get, etc. ad infinitum. The *REAL* advantage of the ramjet is that this is not happening. The fuel is just waiting out there, and it just so happens that the faster you go, the more you're going to collect. Of course, I'm not using the p-p fusion until I'm into the speeds where the beta- decomposition involved is not a problem probability-wise, due to the large number of chances it will have. How's a carbon-catalyzed reaction sound for getting there (except at the lower end, where we'll have to use some conventional engine to attain a speed at which THAT reaction is possible)? Jason Cooper ------------------------------ Date: Sun, 3 Jan 1993 21:16:00 -0600 From: pgf@srl03.cacs.usl.edu (Phil G. Fraering) Subject: Aluminum as rocket fuel \A note of caution: you're assuming that nitrogen is an inert gas. This /isn't necessarily true when hot metals are involved. I'm not sure about \aluminum, but I know titanium will burn fiercely in nitrogen (in fact, /the ash from titanium burning in air is about 80% titanium nitride). \Without an ignition source, the combination might be stable enough. /-- \"God willing... we shall return." | Henry Spencer @ U of Toronto Zoology / -Gene Cernan, the Moon, Dec 1972 | henry@zoo.toronto.edu utzoo!henry Titanium nitride... is that Ti N x y or something along the lines of Ti N O ? x y z In short, is this something that will happen without oxygen whatsoever? -- Phil Fraering "...drag them, kicking and screaming, into the Century of the Fruitbat." <<- Terry Pratchett, _Reaper Man_ PGP key available if and when I ever get around to compiling PGP... ------------------------------ Date: Mon, 4 Jan 1993 04:39:07 GMT From: Henry Spencer Subject: Aluminum as rocket fuel Newsgroups: sci.space In article pgf@srl03.cacs.usl.edu ("Phil G. Fraering") writes: >\... I know titanium will burn fiercely in nitrogen (in fact, >/the ash from titanium burning in air is about 80% titanium nitride). > >Titanium nitride... is that Ti N > x y >or something along the lines of Ti N O ? > x y z > >In short, is this something that will happen without oxygen whatsoever? Yes. Titanium will burn just about as vigorously in pure nitrogen as in air. I expect the nitride is Ti3N4, although I'm not sure of that. A Ti-N-O compound would be a nitrate or nitrite, not a nitride. -- "God willing... we shall return." | Henry Spencer @ U of Toronto Zoology -Gene Cernan, the Moon, Dec 1972 | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Mon, 4 Jan 1993 00:27:49 GMT From: Bruce Dunn Subject: Aluminum as Rocket Fuel? Newsgroups: sci.space > Karl Dishaw writes: > >Bruce Dunn writes: > >When the > >aluminum is melted in the tank, the fuel line, valve, and injector will > all > >be heated to above the melting point of aluminum. > > I'd hate to see the performance hit from carrying a heater that > powerful. Wouldn't it make more sense to pump the aluminum onto the > rocket as a liquid and only have a heater powerful enough to offset > cooling? > Sorry for the sloppy wording. I meant rather "when there is melted aluminum in the tank". I am envisioning a system in which aluminum is premelted, possibly in a solar furnace, and poured into an insulated tank/valve/combusion chamber unit. The aluminum will bring the whole system up to temperature, and melt any residual aluminum from the last firing. I expect that it won't be too hard to insulate the assembly well enough to keep the temperature above the melting point of aluminum for days. I don't think that a heater will be required. If heating is required for long term operation, the logical thing would be to admit a small amount of oxygen into the fuel tank to react with the aluminim and heat it. -- Bruce Dunn Vancouver, Canada Bruce_Dunn@mindlink.bc.ca ------------------------------ Date: 4 Jan 93 03:06:42 GMT From: "Allen W. Sherzer" Subject: DC cost estimates Newsgroups: sci.space In article roberts@cmr.ncsl.nist.gov (John Roberts) writes: >I hope you understand what I mean by the economic term "opportunity cost". Sure I know what opportunity cost is. But I always assumed that the higher opportunity cost was by using Shuttle. I admit I haven't worked out the details but I suspect that for a years Shuttle costs we could could find a way to use Mir for the locker experiments and redesign the few payloads which MUST fly on Shuttle. That would allow us to switch to far cheaper expendables if DC fails and still save money. >Similarly, with the Shuttle as an operational, manned system with a number >of currently unique abilities, The only 'unique capability' which has stood up is the ability to return large payloads. To date there is no demonstrated requirement for this ability. >the fact that it's in use indicates that >those who pay for it (NASA, the government in general, and the public in >general) get get some value out of it. But what is that value and is it worth the money spent? NASA's highest priority is to keep its centers funded. To government, Shuttle is a jobs program. >There are in fact a considerable >number of missions scheduled over the next few years. If the Shuttle program >were cancelled today, those missions would also have to be cancelled, or at >least deferred. Sure, but are those missions being conducted in the most cost effective way? To date, nobody has been able to show that they have been. However, this is all moot. Shuttle cannot be killed; it has too big a constituency. All we can do is hope it doesn't drag us all down with it. >I also have reservations about the "market" argument. Considering for >example the market for human-tended microgravity science experiments >(by "market" I include government and university programs), I don't see >how shutting off US services for several years would help that market to >grow. Who said anything about shutting off services? I didn't. I propose we use Mir and use the savings to fund even more work and perhaps build our own dedicated facility. We might be able to fund this without Shuttle, but we will be very hard pressed to do it WITH shuttle. >One question I'm not sure has been addressed before: is the DC-1 expected to >provide for a "shirtsleeve" environment access tube to the cargo bay, like >the Shuttle? In other words, would a "mini-Spacelab" be a viable option for >a DC-1 payload? A mini-spacelab would be viable. In fact, the DC design allows for delta-V, and duration tradeoffs which make it attractive. there may or may not be access however, between the flight crew and cargo bay (but there is no reason there couldn't be). >[Obviously, the Blancmanges of the planet Skyron are not going to get their >order filled any time soon. Damn good thing too. Otherwise we would have all been turned to Scotsmen long ago and the Blancmanges would have taken Wimbelton. Allen -- +---------------------------------------------------------------------------+ | Allen W. Sherzer | "A great man is one who does nothing but leaves | | aws@iti.org | nothing undone" | +----------------------111 DAYS TO FIRST FLIGHT OF DCX----------------------+ ------------------------------ Date: Mon, 4 Jan 1993 02:36:52 GMT From: "Simon E. Booth" Subject: DC spacecraft capabilities. Newsgroups: sci.space I know I've posted this before, but like I said that part of the thread dissapeared from my site. Here it is again, in case it actually did get out: First, what is the cockpit/crew compartment configuration of the DC-series? (for launch and landing, would the crew be seated vertically or horizontally?) Would a DC spacecraft (properly provisioned of course) be capable of lunar flight? I know the landing gear would have to be strong enough for landing on rough surfaces, but would the spacecraft have the range for such a flight? For lunar landings, the craft would also have to be equiped with an airlock and hatch at the base. I get the impression that even if a DC isn't capable of a direct ascent flight to the moon, extra fuel could be loaded in earth orbit. Or perhaps a variant designed especially for use in space only could be derived from the DC design. What type of ground facilities would be needed? I think it was mentioned here a while back that the payload would be loaded inside a VAB, so would the large shuttle type gantry structures be required, except perhaps for fueling? Simon ------------------------------ Date: 4 Jan 93 05:14:56 GMT From: Henry Spencer Subject: DC spacecraft capabilities. Newsgroups: sci.space In article <1993Jan4.023652.11293@ringer.cs.utsa.edu> sbooth@lonestar.utsa.edu (Simon E. Booth) writes: >Would a DC spacecraft (properly provisioned of course) be capable of lunar >flight? ... If refuelled in orbit, the capability is theoretically there. You'd want to look carefully at the landing-gear issues, life support etc. would need supplementing for the longer trip, and you'd need a suitable module in the cargo bay to provide living quarters and an airlock. >I get the impression that even if a DC isn't capable of a direct ascent flight >to the moon, extra fuel could be loaded in earth orbit... Nothing short of nuclear propulsion will give you a single-stage lunar mission. Orbital refuelling will definitely be necessary. >What type of ground facilities would be needed? I think it was mentioned here >a while back that the payload would be loaded inside a VAB, so would the large >shuttle type gantry structures be required, except perhaps for fueling? No gantry. A few trucks resembling the elevator trucks used at airports. Fuel connections would probably be near the base of the craft, avoiding any need for a gantry for that. -- "God willing... we shall return." | Henry Spencer @ U of Toronto Zoology -Gene Cernan, the Moon, Dec 1972 | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Sun, 3 Jan 1993 21:38:46 -0600 From: pgf@srl03.cacs.usl.edu (Phil G. Fraering) Subject: DC vs. Shuttle capabilities \2. There is limited experience with composite airframes in routine /operational use. Certainly less with composite cryo tanks, if that \route is taken. (The exceptions to this lie in the B-2 program and the /kitplane market, but the B-2 is very early in the flight programs. There \may be some data from "black" programs that MacDac has access to.) Actually, you forgot the F-22/F-23 program as well. And the F-20. I would also note that the kitplane market bit seems to indicate that composites are *better* understood than you think, and aren't being used more widely because of stodgy industry. It sounds like they're more innovative than Boeing/MacDac et al. Perhaps they are. After all, who flew around the world unrefuelled first? THANKFULLY _someone_ had the presence of mind to get Scaled Composites involved on DC-X... \3. The throttled RL-10 with nozzle extender is a new and essentially /untried engine. Engine development is more art than science and has a \history of being subject to delays. I don't think so. There were no changes in any of the "wet" parts of the engine, just the uncooled part of the nozzle. The stupid part of the nozzle, as it were. If we can't do that, we should stay on the ground. \4. The servicing goals and rapid turnaround requirements of the vehicle /are doable on paper, but have been held out as very risky by an \independent study. An independent study which apparently had an axe to grind of its own, if you're talking about the TAC study. \5. The weight margins on the vehicle are very tight, a historical source /of problems in spacecraft and aircraft design. Hmmph. Maybe you should repeat this a couple more times for the people who started this, you'll help them make everyone else think it's true. \Even given all that, the DC-X, DC-Y, DC-1 progression is a valid and /prudent way to develop this class of vehicle. There is one other source \of risk that is hard to quantify at this point: MacDac is an ailing /company, in substantial risk of major cutbacks. Given that the company \is throwing a lot of IR&D money into the project, it could founder on /the rocks of a major financial crisis in the company. I also give \MacDac high marks for the management approach, which I have heard the /project manager give a talk on. It is modeled on the Lockheed "Skunk \Works" approach. I think people were saying the same thing about Apple at about the time they were developing the Mac. Everyone was talking about how they were going to lose out to IBM. But who's in financial trouble now? Also, "we better not give them the project, they're a troubled company" is the sort of self-fufilling prophecy that's kept many many many good alternatives from being tried. \Hopefully, the incoming administration will see the value of the /vehicle, there will be a safe and successful flight test this summer and \it will proceed with the DC-Y. I consider the DC development program a /prudent use of the government's risk capital. However, we need to keep \an eye on alternatives in case the DC program stubs its toe. You say that as if DC isn't one of the alternatives instead of one of the 200-million-a-year-on-design CAD queens. \Edmund Hack - Lockheed Engineering & Sciences Co. - Houston, TX /hack@aio.jsc.nasa.gov - I speak only for myself, unless blah, blah.. \"You know, I think we're all Bozos on this bus." /"Detail Dress Circuits" "Belt: Above A, Below B" "Close B ClothesMode" Phil Fraering |"...Who in the valley shed the poison tear pgf@srl02.cacs.usl.edu | no one knows 318/365-5418 | An old legend of a mythical hero..." ------------------------------ Date: 4 Jan 93 04:41:45 GMT From: Mike Pennell Subject: Justification for the Space Program Newsgroups: sci.space,talk.politics.space 1/3/1993 In response to Justification for the Space Program, The Space Program has all the justification it needs in light of the amount of jobs which have gone out of the U.S. in other industries. LET'S FACE IT, the Aerospace industry is one the last industries we have which is done better here than anywhere else. LET'S KEEP IT HERE. SPEN DA MONEY. MIKE Mike Pennell e-Mail:Pennell@nautile.oe.fau.edu Aerospace Engineer No Job/No Where/No More ------------------------------ Date: 4 Jan 93 00:07:30 GMT From: Barbara Trumpinski Subject: Media and space Newsgroups: sci.space,talk.politics.space In hrubin@pop.stat.purdue.edu (Herman Rubin) writes: >In article <1993Jan2.045416.15301@ringer.cs.utsa.edu> sbooth@lonestar.utsa.edu (Simon E. Booth) writes: >>Concerning public opinion about the space program, IHMO those opinions can >>and are greatly influenced by the media's depiction of space exploration. >>Next time watch news coverage of a shuttle flight. Invariably some reference >>is made to the cost of that particular mission, plus any important technical >>information is either watered down or omitted. >>I've had people tell me that the media doesn't cover the space program very >>much because people aren't interested. >>But here's somethin to think about: did people lose interest and the media >>reduced it's coverage in response, or did the media cut back coverage and then >>convince people that they weren't interested in it? >How much interest SHOULD there be in any particular shuttle launch? If we >had an adequate space program, there should be not much more interest than >in a trip of an ocean liner. As the saying goes, "When man bites dog, >that's news." >The first landing on the moon was quite properly a big media event, but >it is not at all surprising that the later ones were less so. >-- this is true...some of us, a few, are interested in anything about the space program...most people, given the choice between watching (yet another) shuttle launch and an interview with ozzy osbourne will chose ozzy. i think that this is because the media doesn't do enough to present the space program in an interesting manner and because most people don't give a tinker's damn about outer space...we really ARE the minority... barb -- *************************************************************************** conan the librarian a.k.a. kitten /\ /\ barbara ann "my life's a soap opera, isn't yours?" {=.=} ~ trumpins@alexia.lis.uiuc.edu "love is the wild card of existance" rita mae brown ------------------------------ Date: 4 Jan 93 00:45:52 GMT From: "Simon E. Booth" Subject: Media and space Newsgroups: sci.space,talk.politics.space In article hrubin@pop.stat.purdue.edu (Herman Rubin) writes: >In article <1993Jan2.045416.15301@ringer.cs.utsa.edu> sbooth@lonestar.utsa.edu (Simon E. Booth) writes: > >>Concerning public opinion about the space program, IHMO those opinions can >>and are greatly influenced by the media's depiction of space exploration. >>Next time watch news coverage of a shuttle flight. Invariably some reference >>is made to the cost of that particular mission, plus any important technical >>information is either watered down or omitted. > >>I've had people tell me that the media doesn't cover the space program very >>much because people aren't interested. > >>But here's somethin to think about: did people lose interest and the media >>reduced it's coverage in response, or did the media cut back coverage and then >>convince people that they weren't interested in it? > >How much interest SHOULD there be in any particular shuttle launch? If we >had an adequate space program, there should be not much more interest than >in a trip of an ocean liner. As the saying goes, "When man bites dog, >that's news." > >Nor should anyone expect every observation made by a space probe to be >spectacular. Any research program will have experiments or observations >made which are valueless; if we knew what we would find, it would not be >necessary to look for it, unless we can directly exploit it. > >The first landing on the moon was quite properly a big media event, but >it is not at all surprising that the later ones Well, I don't mind that every flight nowadays isn't a media event, but I think the media could at least periodically provide coverage on the overall progress of a project. Simon ------------------------------ Date: 4 Jan 93 01:25:07 GMT From: Pat Subject: Moon Dust For Sale Newsgroups: sci.space,sci.astro In article <3JAN199305333876@kelvin.jpl.nasa.gov> baalke@kelvin.jpl.nasa.gov (Ron Baalke) writes: >>I heard on Paul Harvey radio two days ago that former Gemini and Apollo 15 >>astronaut David Scott had been charged with fraud. No further information >>was presented. Does this auction of the piece of tape have something to >>do with the story report on P.H./ABC News? >INo. it has something to do with a business partnership that was formed in >1980, and is unrelated to the Moon dust. Todays washington post reported in the business section, that David Scott, Former Astronaut from Apollo 15, LEM driver, etc had been charged with fraud in connection with a business partnership he had created. He had apparently collected about 400,000 dollars from various individuals witht he intention of creating a Venture Capital fund, instead, he poured the money into companies and activities owned by Dave Scott. The investors lost their Butts, and are now suing, and pressing criminal charges. ------------------------------ Date: Mon, 4 Jan 1993 01:43:13 GMT From: Mr E Davids Subject: Saturn lift capabilities Newsgroups: sci.space henry@zoo.toronto.edu (Henry Spencer) writes: >It's important to bear in mind that, with program plans and air-drag >forecasts as they were in the mid-70s, it was clear that Skylab would >not re-enter until well after the shuttle was flying and something >could be done about it. There wasn't any feeling of urgency about >reboosting Skylab. Then the US scrapped its remaining manned-spaceflight >capability, the shuttle schedule slipped repeatedly, and air drag >ran well ahead of schedule... The Skylab rescue mission progressively >moved up in the shuttle manifest until it was scheduled for only the >second flight, but even that wasn't good enough in the end. It always seemed to me that there wasn't any interest in keeping Skylab even back then. Skylab as I understood it, was cobbled together out of left overs (I presume ground spares mostly) from as far back as Gemini and hence I always assumed they wanted to be rid of it so that when the time came to build something new, no one could point to it and say they already had a space station. There is of course little evidence to support this point of view (and more importantly, the facts at hand are adequately and more simply explained by the difficulties NASA encountered building and flying the shuttle). Cheers, Enno. ----------- usual disclaimers, etc. Enno Davids enno@eng.monash.edu.au ------------------------------ Date: 4 Jan 93 01:53:12 GMT From: Francois Yergeau Subject: Shuttle a research tool (was: Re: Let's be more specific) Newsgroups: sci.space In article <72827@cup.portal.com> BrianT@cup.portal.com (Brian Stuart Thorn) writes: >>NASA is chartered as a research organization, not an operational agency. >>Shuttle is operations, not research. > > Shuttle is the only manned system we have, so it is in large part > still a research article. I agree, however, that operations is > the major part of the Shuttle system. I guess I disagree with both of these views. If I build a custom laser in my lab, and then operate it purely as a tool to support my research program, I think I am still doing research. Likewise, when NASA is using the shuttle to fly Spacelab, TSS, Hubble, etc, it's doing research. Even a TDRS launch is part of the research effort, since the constellation is used to support various birds doing research missions. The Intelsat rescue was a pretty different story, but even there, they had a defendable position. The shuttle system itself may not be considered R&D anymore, but it's the manifest that tells you whether it's doing research or mere "operations." -- Francois Yergeau (yergeau@phy.ulaval.ca) | De gustibus et coloribus Centre d'Optique, Photonique et Laser | non disputandum Departement de Physique | -proverbe scolastique Universite Laval, Ste-Foy, QC, Canada | ------------------------------ Date: Sun, 3 Jan 1993 23:49:39 -0600 From: pgf@srl03.cacs.usl.edu (Phil G. Fraering) Subject: Space List Flame Wars \I subscribed to this list in order to try to inform myself about the latest /news about US and other coutnries' space programs. I thought that this would \be a list of technical discussions, not a religious debate that has turned /into ad hominem attacks and flame wars as virulent as any I've seen in the \religious news groups. Then I see things like this, from Herman Rubin: >Let those who want to support research decide. But get the governments >out of the way, including out of levying taxes on money going to research. >If the government was not involved in the business of vainly trying to >manage charity, which it does in such a way as to make it financially >advantageous for at least many of those on welfare to do nothing about >the problem, and in the business of keeping our children very poorly >educated, and in general making it expensive to do anything of which >the government diasapproves, there would be the money for space activities. /and this from Henry Spencer: >We'll be mining in space long before we exploit any of the sea-bottom >resources. The socialists rule the oceans and don't want any dirty >capitalist mining venture making money off the "common property of >mankind". The US State Department was on the brink of giving them the >rest of the universe too, but the L5 Society (may it rest in peace) >managed to block Senate ratification of the infamous Moon Treaty. \Such political ranting belongs in the alt.talk.politics or alt.religion /groups. Could we please take them out of the space list? 1. Henry Spencer's little excerpt isn't political ranting but a good summary of the facts. If you don't think so, you need to look at the background of the COPOUS Treaty. 2. Currently our space programs are run mainly by the government, and as such are currently constrained more by the sort of corrupt behavior normally called "the political realities of the situation." The people trying to push this off into other newsgroups, which are accesible neither for posting nor reading purposes to much of the internet population, are IMHO either ignorant of the status quo or actively supporting said status quo, which has spent some 200 billion dollars in space in the last 20 years, and couldn't do in ten years what was done in eight years thirty years ago (put a man on the moon). There's a not very nice, but accurate term, for such people. \In addition, there is much too much signal to noise ratio in the flame wars /and the ad hominem attacks. Could we move them out of the list and into \private emails? There is too much heat and not enough light coming out /of them. I agree with you here. But the odd thing is, most of the attacks seem to be centering around an experimental project, one of the few the gubbimint seems to be doing right, that both has much potential to lower launch costs and has a total cost of less than a shuttle launch. \I know that I have now left myself wide open to being attacked from all /sides, but I just thought that, considering the size of the mailings that I'm \getting, there is too much of this stuff to wade through to get to anything /worth reading. You'll probably be hearing from Euzkadi Fatherland and Liberty in the morning. It was nice hearing from you this once, though... once... ;-) And if he had signed his name, I could have attributed it. One of the hazards of posting by mail... Phil Fraering |"...Who in the valley shed the poison tear 318/365-5418 |no one knows... pgf@srl02.cacs.usl.edu|An old myth of a mythical hero..." ------------------------------ End of Space Digest Volume 15 : Issue 629 ------------------------------