Date: Fri, 20 Nov 92 05:04:12 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #441 To: Space Digest Readers Precedence: bulk Space Digest Fri, 20 Nov 92 Volume 15 : Issue 441 Today's Topics: FREE-ENERGY TECHNOLOGY For Spacecraft Galileo HGA: Hypothesis (4 msgs) Lunar "colony" reality check Lunar "colony" reality check, part 2 opening of the first self-sufficient solar house, Press Release ROTATION OF THE MOON (2 msgs) Scientific method Scientific method (followup) Shuttle replacement (4 msgs) Space suit research? SSTO Viability (was: Shuttle replacement) 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: Thu, 19 Nov 1992 16:20:18 GMT From: George Noyes Subject: FREE-ENERGY TECHNOLOGY For Spacecraft Newsgroups: sci.space >In article <1992Nov17.164440.2394@cnsvax.uwec.edu> mcelwre@cnsvax.uwec.edu writes: Note: the following comments plagerized...... > [vague generalities removed] > [folklore removed] > [political dogma removed] >> Robert E. McElwaine >> B.S., Physics, UW-EC > What has this McElwaine been smoking? It must be pretty good! ------------------------------ Date: Thu, 19 Nov 1992 23:29:23 GMT From: Henry Spencer Subject: Galileo HGA: Hypothesis Newsgroups: sci.space In article <246900037@peg.pegasus.oz.au> wlmss@peg.pegasus.oz.au writes: > Another naive query about Galileo's HGA problem. > Can it send data at a high rate but with little power? The HGA is useless in its current state. The low-gain antennas can send high-rate data, if a receiver is relatively close. > If so, what if a relay craft were sent after it to gather and > send information back at the intended rate? This was the most technically-feasible way to salvage the complete mission. Put the relay craft in high orbit around Jupiter, and the Galileo LGAs can get the high data rate that far. A light relay craft could be launched on a more direct trajectory to reach Jupiter in time. It hasn't been done, basically because it required commitment to a modest but substantial expenditure very quickly, and NASA can't *do* that nowadays. -- MS-DOS is the OS/360 of the 1980s. | Henry Spencer @ U of Toronto Zoology -Hal W. Hardenbergh (1985)| henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Fri, 20 Nov 1992 00:09:16 GMT From: Leigh Palmer Subject: Galileo HGA: Hypothesis Newsgroups: sci.space In article <246900037@peg.pegasus.oz.au> wlmss@peg.pegasus.oz.au writes: > > > > Another naive query about Galileo's HGA problem. > > Can it send data at a high rate but with little power? > > If so, what if a relay craft were sent after it to gather and > send information back at the intended rate? > > Would this work? > > > o < < < < < < < < < < < < )-x . . . . )-G > > earth relay Galileo > Sure, but how are you going to *keep* the relay at that point between Earth and Galileo? You'd pretty much have to put it in orbit around Jupiter or place it in the inner Lagrangian point. In any smaller orbit it'd orbit faster than Jupiter, and thus spend most of its time at least as far from Galileo as Earth is now. Another idea: Put a really large radiotelescope in Earth orbit and hook it to the Deep Space Network. I saw a marvelous scheme for doing this once in a story about nitinol, the memory alloy. One makes a flimsy lacework paraboloidal antenna which has a conductive path arranged such that applied current flows through all the nitinol wires in the structure. It is fabricated at high temperature and then cooled off, wadded into a much smaller package, and shipped to orbit. Once there a large current throgh the wires restores the paraboloid to its original shape! Oh well, so much for the science fiction writing today. I'll go finish marking exams. Leigh Leigh ------------------------------ Date: Thu, 19 Nov 1992 23:22:55 GMT From: David Knapp Subject: Galileo HGA: Hypothesis Newsgroups: sci.space In article <246900037@peg.pegasus.oz.au> wlmss@peg.pegasus.oz.au writes: > > > > Another naive query about Galileo's HGA problem. > > Can it send data at a high rate but with little power? > > If so, what if a relay craft were sent after it to gather and > send information back at the intended rate? > > Would this work? > > > o < < < < < < < < < < < < )-x . . . . )-G > > earth relay Galileo > > It's not a naive query at all since it was already considered by NASA. The problem is getting the major funding this would require, and getting things designed, built and launched in time. There might Not even be a window left for a rendezvous. -- David Knapp University of Colorado, Boulder Perpetual Student knapp@spot.colorado.edu ------------------------------ Date: Fri, 20 Nov 1992 00:54:26 GMT From: Henry Spencer Subject: Galileo HGA: Hypothesis Newsgroups: sci.space In article <1992Nov20.000916.4853@sfu.ca> palmer@sfu.ca (Leigh Palmer) writes: >... how are you going to *keep* the relay at that point between Earth and >Galileo? You'd pretty much have to put it in orbit around Jupiter... You *have* to put it in orbit around Jupiter. Putting a relay halfway between Earth and Jupiter is utterly useless; it has to be practically in Galileo's back pocket for it to receive high-rate transmissions from the low-gain antennas. >Another idea: Put a really large radiotelescope in Earth orbit and hook it to >the Deep Space Network... There really is very little advantage to doing this in orbit. Lighter construction, yes, but much higher costs and no maintenance access. With the current state of space transportation, you're better off building it on Earth. -- MS-DOS is the OS/360 of the 1980s. | Henry Spencer @ U of Toronto Zoology -Hal W. Hardenbergh (1985)| henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Thu, 19 Nov 1992 22:31:16 GMT From: Henry Spencer Subject: Lunar "colony" reality check Newsgroups: sci.space,alt.sci.planetary In article <1992Nov19.020207.11499@gucis.cit.gu.edu.au> wharvey@gucis.cit.gu.edu.au (Wayne Harvey) writes: >I seem to remember some theory a while back that the moon was actually >*captured* by Earth at some stage (I think it was about 800 million >years ago)... The three classical theories of lunar formation -- fission from Earth, formation in orbit around Earth, and capture -- were all pretty much destroyed by analysis of the Apollo samples. Earth and Moon are too similar to have formed far apart, and too different to have formed together unless you add some extra factor to give them very different histories. The giant-impact theory fits the bill, and the facts. >... when you assume that the only mineral explorations done on >the lunar surface were conducted in the equivalent of the Sahara. Not a very tenable assumption. For one thing, those explorations got samples from a much wider range of locations, courtesy of splashes from meteorite impacts. For another, even the "local" rocks differed a great deal between sites. (The lunar scientists were against landing Apollo 12 at a site that looked so similar to the Apollo 11 site, but they shut up when they saw the preliminary results from the Apollo 12 samples.) There's no doubt that we've sampled only a little of the Moon's geological diversity -- and useful ore bodies are often very localized things, the results of extreme conditions -- but we do have enough data to be fairly confident of the average composition. -- MS-DOS is the OS/360 of the 1980s. | Henry Spencer @ U of Toronto Zoology -Hal W. Hardenbergh (1985)| henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Thu, 19 Nov 1992 21:58:50 GMT From: Edmund Hack Subject: Lunar "colony" reality check, part 2 Newsgroups: sci.space In article roberts@cmr.ncsl.nist.gov (John Roberts) writes: > [regarding the need for spares for a lunar base] >What can be done to help >alleviate the problem? Breaking designs up into smaller modules, and having >as many identical modules as possible might help. Using initially identical >but reconfigurable modules could also be useful. (Earthbound example: I just >finished a circuit design in which a high percentage of the logic is in >identical reprogrammable logic devices, each one programmed differently. >By keeping a relatively small number of spares on hand, I could replace >any of these devices that might fail. If for some reason I had no spares >and really needed to use the circuit, I could cannibalize a component from >a less-critical area, and use it to replace a failed device in a more-critical >area.) This is one idea that the NASA First Lunar Outpost has proposed. Even Freedom has (partly) endorsed this, with only a few types of circuit boards for the onboard computers. Having the ability to do sub-board level repairs could greatly improve availability of the systems and reduce the logistics burden, IMHO. We are attempting to quantify this in the future. > >As I posted long ago, I suspect a first mission would be likely to choose to >start with a minimal set of spares, and hope to later build up a stock by >periodic resupply. (Or they might send supplies ahead of them, by unmanned >vehicle.) Both are being looked at. Also, most scenarios have the base landing and auto-deploying a few months before the crew so that a couple of night/day sequences happen, shaking early failures out. Massis allocated in the crew lander for last-minute spares to be included. -- 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" ------------------------------ Date: Thu, 19 Nov 1992 23:01:24 GMT From: Henry Spencer Subject: opening of the first self-sufficient solar house, Press Release Newsgroups: sci.energy,sci.space In article <2518@ispi.COM> jbayer@ispi.COM (Jonathan Bayer) writes: >The Appollo 13 failure was due to an oxygen tank being dropped during >assembly into the service module. The drop was about three inches, and >the tank was throughly test after it was dropped. However, a small tube >apparently had been dislodged, and it wasn't detected during the >testing. It was only functional in weightlessness. The tube was some >sort of relief tube. When they turned on the internal mixers in flight >(the mixers kept the O2 from clumping in one area) there was an >explosion... This actually leaves out an important intermediate step. The (probable) drop damage to the tank wasn't directly responsible for the accident. Its main effect was to make it difficult to empty the tank after ground tests. And that is where the real problem crept in. When the tank wouldn't empty after a test, the tank's heaters were used to boil it dry... and thanks to another error or two along the way, the tank was drastically overheated and nobody realized it. This roasted the Teflon insulation on the in-tank wiring. In flight, when the tank stirrer was turned on, shorts through the ruined insulation produced sparks, the insulation ignited, and things went downhill quickly from there. References: Cooper, "Thirteen: The Flight That Failed". Murray&Cox, "Apollo: The Race To The Moon". NASA SP-350, "Apollo Expeditions To The Moon". NASA SP-4204, "Moonport". NASA SP-4214, "Where No Man Has Gone Before". >... When they released the >service module they were able to see where the explosion had occurred. Actually, not true except in a very general sense. They didn't have a very good view and that bay of the Service Module was quite a mess. -- MS-DOS is the OS/360 of the 1980s. | Henry Spencer @ U of Toronto Zoology -Hal W. Hardenbergh (1985)| henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Thu, 19 Nov 1992 22:02:46 GMT From: Michael Andersson Subject: ROTATION OF THE MOON Newsgroups: sci.space In article <1992Nov19.144441.5498@col.hp.com> dag@col.hp.com (David Geiser) writes: >> The same thing is happening, much more slowly, to the earth -- >> friction with the tides and within the "solid" earth is slowing the >> rotation rate by something on the order of 1 sec every century. We can >> actually measure it (the slowdown) nowadays. Love those atomic clocks! > >Do you know if that rate is constant? Say around 63M years ago, >around the time of the end of the dinosaurs, the day would have >been 175 hrs longer! No. If the rotation is slowing, then days used to be shorter. ------------------------------ Date: Thu, 19 Nov 1992 23:16:13 GMT From: David Knapp Subject: ROTATION OF THE MOON Newsgroups: sci.space In article sheppamj@sun.soe.clarkson.edu (Matthew Sheppard) writes: > >Question: > Why is the moon orbiting the earth at the same rate it rotates? It >can't be pure luck that the same side of the moon is always facing us. It's not pure luck. In fact, this phenomenon, called 'tidal locking' is almost the rule in the solar system. Tidal forces from the Earth and Sun cause a 'bulge' in the moon. On earth, you can literally see the bulge effect in the tides. On the moon (and on the earth too, actaually) the body *itself* is bulged out. As the moon rotates through this bulge, the flexing causes the moon to warm up and dissipate the rotational energy. After a while, the moon has 'despun' and no longer rotates through the bulge. That's how it is now. >Perhaps someone already tried to send us a message and we just haven't >read it yet. I won't touch that one. -- David Knapp University of Colorado, Boulder Perpetual Student knapp@spot.colorado.edu ------------------------------ Date: Fri, 20 Nov 92 01:29:11 EST From: John Roberts Subject: Scientific method -From: mccall@mksol.dseg.ti.com (fred j mccall 575-3539) -Subject: Re: NASA Coverup -Date: 18 Nov 92 21:38:47 GMT -Organization: Texas Instruments Inc ->]No, what you have is necessary, but not sufficient. It must also be ->]testable and make some predictions about the universe to be as viable as ->]relativity (General or Special). (This is true to first order. I am ->]aware that there is some discussion in philosophy of science about ->]falsifiability, as well as other nits.) -This is pretty much REQUIRED for a scientific 'theory' -- it must -exhibit sufficient predictive power to be falsifiable. In other -words, it must predict things that we can go look at that we don't -know the answers to yet, so that we can then go and see if the things -that it predicts are true. -Fred.McCall@dseg.ti.com - I don't speak for others and they don't speak for me. For better or worse, that's what the "scientific method" is today, but it was not always thus. Gregor Mendel, pioneer geneticist, used a somewhat different method. I'm not sure exactly what he did, but I believe that in essence, he developed his theory and ran his experiments more as "parallel processes" than what would be considered acceptable today. I've sometimes wondered whether there's a lesson to be learned in the alternative techniques used in the past. Others may be thinking along similar lines - for instance, for instance, the Earth-impact model of the formation of the moon has risen from obscurity to the "most favored model", with (as far as I know) little or no new input of information - it's based on mathematical models and old Apollo and Voyager data. (Eventually, of course, somebody will try to come up with new experiments to "test" the model, but I consider the fact that it seems to have effectively achieved the status of "theory" without the traditional requirement of further testing to be significant.) Does anybody recall the details of the technique Mendel used? John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: Fri, 20 Nov 92 01:44:43 EST From: John Roberts Subject: Scientific method (followup) For those who *insist* on the classical method of development of theory followed by testing for previously unobserved supporting phenomena, the current condition of HST offers a priceless opportunity. They can develop their hypotheses now, then after the installation of WF/PC II and COSTAR, they can look again in more detail. (This was discussed on Thursday with respect to the discovery of the accretion disk.) John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: Thu, 19 Nov 1992 23:09:04 GMT From: Henry Spencer Subject: Shuttle replacement Newsgroups: sci.space.shuttle,sci.space In article hugh@whio.cosc.canterbury.ac.nz (Hugh Emberson) writes: >Henry> Gary Hudson claims that you could put six SSMEs on a shuttle external >Henry> tank, without SRBs, and get it into orbit carrying a payload about 50% >Henry> greater than the shuttle's... > >This sounds a lot like Shuttle-C... Not very closely related, actually, since Hudson's design deletes the SRBs and doesn't put engines+payload in a mock-orbiter. >...whatever happened to that idea? Too little demand and too much politics. It quietly died. >...idea was to take a normal stack (an ET and 2 SRBs) and bolt on a >fairing containing the payload and some SSMEs in place of the shuttle. That's right. The fairing started out to be a stripped-down orbiter, but it didn't take long to figure out that if you're throwing it away, there are cheaper ways to build it. >... Some of the pictures I saw had 4 SRBs. There have been a wide variety of shuttle-derived heavylift-booster designs over the years. It looks like a sensible thing to do if you've got a few heavy payloads to lift and don't want to invest in developing a whole new launch system (including new pads etc.) just for them. The idea has been revived once again by Griffin's how-to-launch-the-space- station "red team". -- MS-DOS is the OS/360 of the 1980s. | Henry Spencer @ U of Toronto Zoology -Hal W. Hardenbergh (1985)| henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Thu, 19 Nov 1992 23:23:00 GMT From: Henry Spencer Subject: Shuttle replacement Newsgroups: sci.space.shuttle,sci.space In article <1992Nov19.073340.27278@netcom.com> hage@netcom.com (Carl Hage) writes: >: This BTW is a source of trouble for SSTO. > >A source of trouble? HL20 won't win any arguments claiming to be better >because it's more expensive... Remember that money = jobs; being a lot cheaper is *not* an unmixed political blessing. The big problem HL20 presents for SSTO is that a lot of NASA people see HL20 as work for them and SSTO as work for somebody else... and NASA is the established source of expertise on spaceflight, so any space project that NASA dislikes has an uphill battle ahead of it. (This isn't a new problem, by the way.) All the more so because SSTO challenges NASA's credibility, not just its turf, by being (if it works) a vastly-superior system built at low cost with off-the-shelf technology. This is bad news if you've spent your career defending very expensive projects as "the only way it can be done". >Claims of $1M or even $10M launch costs seem too low to be believable. >... Does your info kit offer clear and complete >information that will convince a skeptic? Nothing short of a flight demonstration will convince really skeptical observers. A successful on-budget DC-X, especially with a demonstration of rapid reflight with minimal refurbishing, will help a lot. >It seems like it is a matter of a few simple calculations to show that >it is theoretically possible/impossible given some basic assumptions >about current rocket technology like, weight, engine efficiency, fuel >weight, etc. Presumably you have shown that it is possible. It's been (theoretically) possible at least since the 60s, perhaps earlier. (Ed Heinemann, Douglas's military-aircraft miracle-worker, sketched an expendable SSTO launcher in the late 40s... Pity he never got the chance to build it.) -- MS-DOS is the OS/360 of the 1980s. | Henry Spencer @ U of Toronto Zoology -Hal W. Hardenbergh (1985)| henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Thu, 19 Nov 1992 23:37:24 GMT From: Henry Spencer Subject: Shuttle replacement Newsgroups: sci.space.shuttle,sci.space In article steinly@topaz.ucsc.edu (Steinn Sigurdsson) writes: >... the operation costs do seem quite optimistic, in >particular I'd have thought the early years operation would be higher >while ground support learned some maintenance procedures and >operational experience was developed on what needs inspection and >refurbishing between flights? I just don't see any way around that, >are the DCs really that much simpler? Wrong question. There are two ways to go about this. One is to assume that between-flights turnaround will be very complex, but it will get better if we look for ways to improve it. The other is to assume that it will be simple, although a few complications may be found. Oddly enough, only the second approach ever results in something simple and cheap. You can always come up with reasons why complexity is needed, especially after you've already written the manuals and hired the staff. Simple systems do not evolve from complex ones. The right question is: why should the DCs be much more complex than high-performance aircraft? -- MS-DOS is the OS/360 of the 1980s. | Henry Spencer @ U of Toronto Zoology -Hal W. Hardenbergh (1985)| henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 20 Nov 92 01:44:36 GMT From: Steinn Sigurdsson Subject: Shuttle replacement Newsgroups: sci.space.shuttle,sci.space In article henry@zoo.toronto.edu (Henry Spencer) writes: In article steinly@topaz.ucsc.edu (Steinn Sigurdsson) writes: >... the operation costs do seem quite optimistic, in >particular I'd have thought the early years operation would be higher >while ground support learned some maintenance procedures and >operational experience was developed on what needs inspection and >refurbishing between flights? I just don't see any way around that, >are the DCs really that much simpler? Wrong question. There are two ways to go about this. One is to assume that between-flights turnaround will be very complex, but it will get better if we look for ways to improve it. The other is to assume that it will be simple, although a few complications may be found. Oddly enough, only the second approach ever results in something simple and cheap. You can always come up with reasons why complexity is needed, especially after you've already written the manuals and hired the staff. Simple systems do not evolve from complex ones. The right question is: why should the DCs be much more complex than high-performance aircraft? Intrinsically I see no reason why an orbital launcher should be more complex than that - as a matter of practicality though there is the fact that you have a lot of energy to be controlled in a very short time - the SSME's power rating is a respectible fraction of US capacity! Now, the DCs are not being designed on the margin, they have to be robust if they are not to be stripped down and inspected every time. I guess my question really is whether they've succeeded in reducing the number of parts _and_ gotten the reliability of each part to the point where maintenance will be as low as claimed. There is no intrinsic reason why it can't be done, but it is not clear that the knowledge base to decide what is necessary refurbishment and what is waste is there yet. Of course the only way to find out is to fly the thing :-) | Steinn Sigurdsson |I saw two shooting stars last night | | Lick Observatory |I wished on them but they were only satellites | | steinly@lick.ucsc.edu |Is it wrong to wish on space hardware? | | "standard disclaimer" |I wish, I wish, I wish you'd care - B.B. 1983 | ------------------------------ Date: Thu, 19 Nov 1992 22:40:31 GMT From: Henry Spencer Subject: Space suit research? Newsgroups: sci.space In article prb@access.digex.com (Pat) writes: >Okay. I know commercial jets routinely push 40,000 ft, maybe a bit more. >the cabins are usually only pressurised to 10 PSI. and they use air cooling >on lots of stuff. they also have gear in unpressurised bays that seem >to cope... I don't know for sure, but I believe almost all of their avionics are in pressurized bays. There isn't much unpressurized space in a pressurized airliner, except at the extreme nose and tail. >Military jets run up to 70,000 ft and over 100,000 on special >trajectories, but if they dont use air cooling then that would explain it. Very few military jets ever get up to 70,000ft. 50,000 is a more typical ceiling for reasonable configurations. Only the specialized ones can even reach 70,000 except in a ballistic trajectory. >I think the blackbirds cruise at 100,000 ... This is popular mythology, but so far as I know it has never been confirmed. The openly-admitted Blackbird altitude records are in the 70-80 range. >Actually could a blackbird pilot get astronauts wings? on some sort of ballistic shot???? It's most unlikely. All of the altitudes we're talking about are *way* below "astronaut wings" altitude. And the Blackbird is not particularly well-suited to ballistic trajectories; the ballistic-trajectory altitude record is held by the F-15, not the Blackbird, and it's only about 100,000ft. >>>ALSO in apollo were EVA's part of the planned mission? >>Yes, both on early flights for testing, and on the later lunar missions >>for recovery of film canisters from the SM survey-equipment bay... > >i thought they needed to get something out of the SM on the trip home. Please read what I wrote, Pat! On the later lunar missions the SM had one bay full of remote-sensing equipment, and they needed to recover film from it. There were no such EVAs on the earlier lunar missions. -- MS-DOS is the OS/360 of the 1980s. | Henry Spencer @ U of Toronto Zoology -Hal W. Hardenbergh (1985)| henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Thu, 19 Nov 1992 22:52:13 GMT From: Bill Goffe Subject: SSTO Viability (was: Shuttle replacement) Newsgroups: sci.space.shuttle,sci.space aws@iti.org (Allen W. Sherzer) writes: [material deleted] >>When a project goes from zero visibility to the network news, it makes >>all the difference in the world because most politicians (and most >>Americans) don't care about anything that doesn't make the network >>news. (Let's just hope the launch happens on a slow news day.) >We need to do other things as well. There was an article on this in >a recent issue of Design News and the British newspaper The Guardian >is also working on an article. I understand that there will be an article in the British newspaper The Daily Telegraph on Nov. 20. Bill Goffe bgoffe@seq.uncwil.edu ------------------------------ From: Steinn Sigurdsson Newsgroups: sci.space.shuttle,sci.space Subject: Re: Shuttle replacement Message-Id: Date: 19 Nov 92 21:50:44 GMT References: <1992Nov17.194901.16883@aio.jsc.nasa.gov> <1992Nov19.073340.27278@netcom.com> <1992Nov19.202302.5796@iti.org> Organization: Lick Observatory/UCO Lines: 60 Nntp-Posting-Host: topaz.ucsc.edu In-Reply-To: aws@iti.org's message of 19 Nov 92 20:23:02 GMT Sender: news@CRABAPPLE.SRV.CS.CMU.EDU Source-Info: Sender is really isu@VACATION.VENARI.CS.CMU.EDU In article <1992Nov19.202302.5796@iti.org> aws@iti.org (Allen W. Sherzer) writes: In article <1992Nov19.073340.27278@netcom.com> hage@netcom.com (Carl Hage) writes: >Although Gore was flamed here for this speech, it would seem to me that he >could be a very strong supporter of SSTO. Let's hope so. >Development of DC-X has been relatively low cost, but can you convince >everyone that DC-1 will be cheap? Are the cost predictions realistic? No, you can never convince everybody. However, the cost predictions are the best available. If nothing else the fact that the design and construction of DC-X is on time and on budget gives a good indication that their cost estimators know what they are talking about. ... >Claims of $1M or even $10M launch costs seem too low to be believable. Only circumstantial. If the models are correct than DC will fly for $1 to $10M per flight. However we need DC-X to verify the models. However the circumstantial evidence supports it. After all, the cost and part count of a launcher is about the same as a commercial airliner. The rest is up to the technology and to date nobody questions that it can be done as far as the technology is concerned. While I'm strongly in favour of the DC-X/Y/1(-2-3!) this causes me a little concern. I'm willing to believe that the DCs can be developed and constructed on budget as long as they can avoid some appropriations nightmare, but the operation costs do seem quite optimistic, in particular I'd have thought the early years operation would be higher while ground support learned some maintenance procedures and operational experience was developed on what needs inspection and refurbishing between flights? I just don't see any way around that, are the DCs really that much simpler? >For point 3, there seems to be a particular timetable in mind for >producing DC-X/Y/1. How does that timetable compare with the alternatives? An operational DC-1 should be flying in 97 IF (this is a big if) we can get Congress to fund it properly. BTW, since we are only looking at $1B per year over about four years this is an achieveable goal provided supporters put and keep pressure on Congress. Hmm, didn't you just say that Congress should just fund the DC-X,Y? I thought after prototyping McD would pay for construction of the production models! ;-) +---------------------------------------------------------------------------+ | aws@iti.org | nothing undone" | +----------------------156 DAYS TO FIRST FLIGHT OF DCX----------------------+ | Steinn Sigurdsson |I saw two shooting stars last night | | Lick Observatory |I wished on them but they were only satellites | | steinly@lick.ucsc.edu |Is it wrong to wish on space hardware? | | "standard disclaimer" |I wish, I wish, I wish you'd care - B.B. 1983 | ------------------------------ End of Space Digest Volume 15 : Issue 441 ------------------------------