Date: Sat, 12 Dec 92 05:10:14 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #535 To: Space Digest Readers Precedence: bulk Space Digest Sat, 12 Dec 92 Volume 15 : Issue 535 Today's Topics: "success oriented" absolutely, positively overnight (2 msgs) Air Force One Aurora Cassini Undergoes Intensive Design Review Earth Movie Jet Lag liquid fuels Mach 8+ Space/Spy Plane? Orbit Question? Presidential DC-1? Profit in space activities (was: absolutely, positively overnight) Saturn history Scud Missile technology (2 msgs) Shuttle replacement Shuttle thermal tiles Terminal Velocity of DCX? (was Re: Shuttle ...) WFPC-2 Will Magnify Hubble's Views of the Universe what the little bird told Henry 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: Fri, 11 Dec 92 21:25:52 EST From: John Roberts Subject: "success oriented" -From: ewright@convex.com (Edward V. Wright) -Subject: Re: what the little bird told Henry -Date: 11 Dec 92 17:56:29 GMT -Organization: Engineering, CONVEX Computer Corp., Richardson, Tx., USA -I'd be curious to know the exact date, sometime in the last 20 years, -when "success oriented" became a pejorative phrase. Yeah, the project -is success oriented. Just like Project Apollo. The alternative, I -guess, is for a project to be "failure oriented." I like success better. In that context, I'd say that "success oriented" means that everything in the design process has to work right the first time, or the project is judged a failure. (In other words, the design process *assumes* success at every stage - there are no provisions for setbacks.) Perhaps another term would be better - like "recklessly self-assured". I don't think you could call Apollo success oriented - there were numerous backup design paths, redundant test spacecraft (for instance, five Lunar Orbiters were made and used, though three were sufficient to map the Apollo landing sites), and the program progressed in many incremental stages, testing various aspects of the mission in turn. It was considered a very high priority to have a successful mission within a specific time frame, and they approached the problem by throwing vast quantities of money at it. The DC program is more success oriented than Apollo, but that's part of the idea of the design approach (as you point out) - taking higher risks in the design process with the potential payoff of lower design costs, and *perhaps* shorter design time. But even DC is testing things in stages - two generations of prototype craft, and a careful testing sequence for each prototype. So perhaps "success oriented" is not the best way to describe the program. John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: Fri, 11 Dec 1992 01:50:59 GMT From: Mary Shafer Subject: absolutely, positively overnight Newsgroups: sci.space On 11 Dec 1992 00:45:47 GMT, anthony@csd4.csd.uwm.edu (Anthony J Stieber) said: A> Are the speeds SR-71 craft fly at A> considered hypersonic? No, they're not. Essentially, it's not hypersonic below about Mach 5. The definition floats around depending on who you're talking to, but Mach 5 is a number that's pretty much agreed on. At Mach 3, the heating is starting to become interesting, but it's not really interacting with the aerodynamics. At Mach 5, the heating is interacting with the aerodynamics. -- Mary Shafer DoD #0362 KotFR NASA Dryden Flight Research Facility, Edwards, CA shafer@rigel.dfrf.nasa.gov Of course I don't speak for NASA "A MiG at your six is better than no MiG at all." Unknown US fighter pilot ------------------------------ Date: Thu, 10 Dec 1992 23:46:25 GMT From: Josh 'K' Hopkins Subject: absolutely, positively overnight Newsgroups: sci.space henry@zoo.toronto.edu (Henry Spencer) writes: I had written... >>I'm no expert on jet lag. It just seems like going from breakfast to a late >>dinner in the time it takes to skim a good magazine would have to throw your >>system off. Since jet lag is way off the subject... >Actually, not entirely off the subject. >The problem in jet lag is the timezone change from origin to destination. >How long it takes to get there is, to a first approximation, irrelevant. >Although the airlines often make some attempt to smooth the transition, >you can think of the situation as staying on origin time until you step >off the plane, at which point you suddenly have to shift to destination >time. >However, on closer examination, trip time is relevant... because a long >fatiguing trip can only make the problem worse. The shorter the better. In my experience being on a plane is no problem - it's those darn terminals that make it a pain. I remember flying Paris-Cleveland and spending the majority of the time on the ground. Trust me, JFK at 2 AM isn't fun. Intercontinental travel via suborbital vehicle will be just as much of a pain unless we also solve scheduling, passenger processing and ground transport problems. On the subject of jet-lag, I think you may have made a few incorrect assumptions. I use time on the plane to at least start to adapt, or at least I think I do. I can go to sleep a little early or a little later. If I fly aboard TranSpace airlines I won't have time to sleep - I'll just have to deal with it when I get there. >(I assume we're talking about surface-to-surface travel, not surface-to-space, >which is a very different market with a proven audience.) That was the subject in mind. I agree on space tourism. Do you have any numbers to post though? -- Josh Hopkins jbh55289@uxa.cso.uiuc.edu Ho^3 !=L ------------------------------ Date: Fri, 11 Dec 92 20:54:03 EST From: John Roberts Subject: Air Force One -From: gary@ke4zv.uucp (Gary Coffman) -Subject: Re: absolutely, positively overnight -Date: 11 Dec 92 17:24:37 GMT -Organization: Gannett Technologies Group ->I'm sure that if certification were suitable and appropriate facilities ->were widespread, there'd be a few executive DC-1s bought. The Saudi ->royal family would surely buy one. And then there's Air Force One... -Take a look at Air Force One, or Two. A 747 and a 707. I was under the impression that there are two 747s. There was a television special on the history of Air Force One several months ago, but I don't think I saved the tape. (One amusing anecdote from the show - when Kissinger was Secretary of State, he had quite a reputation as a "ladies' man". He would be seen at a party on Friday night with one of various women, then disappear, and show up again on Monday, looking exhausted. In fact, he would drop off the woman after leaving the party, go to Andrews, and take Air Force One to Europe for secret talks with the North Vietnamese. I suppose he became an expert on the subject of jet lag. :-) -The Air Force -is very conservative in the choice of aircraft on which to fly the -President. The Saudi royals are even more conservative. Maybe a -playboy nephew might be allowed on a high performance aircraft, -but none of those directly in line for the throne. In contrast, King Hussein of Jordan has been known to fly *himself* to DC for a conference with the President. John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: Thu, 10 Dec 1992 23:31:26 GMT From: Brad Whitehurst Subject: Aurora Newsgroups: sci.space In article PHARABOD@FRCPN11.IN2P3.FR writes: >Bob Waterman writes (8 Dec 92 22:19:48 EST): > >>Thought Y'all might find this interesting (those financial guys >> >>From Wall Street Journal... >> >>Magazine Suggests Aircraft Has Flown Mach 8 for Years >> ... (too long, suppressed) ... > >Very interesting indeed. Thanks for posting that article. >Now a few comments about this mysterious triangular aircraft: > >1). In the article "Recent Sightings of XB-70-like Aircraft Reinforce >1990 Reports from Edwards Area", AW&ST (August 24, 1992) reports a few >sightings of what they assume to be a TSTO (Two Stages To Orbit) object. >The first sightings (1990-1991) were of a "primarily delta-shaped" >aircraft. Only in the two last sightings (1992) were reported a "narrow >fuselage" and/or a "forward wing or canard". Maybe these two last >sightings can be discarded (IMHO, all these sightings are no more >convincing than UFO sightings: just apply the CSICOP criteria to >these AW&ST articles...). If they can be discarded, then we are left >with reports of "triangular" aircrafts in the Wall Street Journal and >in the AW&ST article. My conclusion: maybe Aurora and the "XB-70-like" >aircraft are the same beast, in which case there is no TSTO, only a >hypersonic spy plane. > >2). Unknown triangular crafts have been reported over Belgium in 1989- >1990-1991, and there have been more than a few sightings: something >like one thousand! On the only good photo which exists of this object, >it has a 82-degrees nose, not far from the 75-degrees reported in the >Wall Street Journal (I know, it depends on perspective). However, these >crafts could hover silently. Could Aurora go at Mach 8 and also hover >silently? Seems very unlikely. So the Belgian objects were probably >not Aurora, maybe just a hoax... but: > >3). In its December 1991 issue, Popular Mechanics (article "America's >New Secret Aircraft") reports, near Edwards AFB, a big triangular object >which, like the Belgian object, can hover silently horizontally and >vertically... Hence the hypotheses: > >a) The USA have really a extraordinary triangular plane, which can >both hover and reach Mach 8. > >b) The USA have a triangular spy plane which goes at Mach 8, and a >triangular airship which looks like this plane. Maybe the airship >has been built just in order to confuse people. > >c) Popular Mechanics and AW&ST are no more serious than UFO reviews. > >J. Pharabod I'll believe AW&ST over the Wall Street Journal and Pop Mechanics any day! They've got an intelligence net second only to the CIA...hmmm, mebbe even better! -- Brad Whitehurst | Aerospace Research Lab rbw3q@Virginia.EDU | We like it hot...and fast. ------------------------------ Date: Thu, 10 Dec 1992 23:25:27 GMT From: Hayim Hendeles Subject: Cassini Undergoes Intensive Design Review Newsgroups: sci.space In article <1992Dec10.053616.8145@news.arc.nasa.gov> baalke@kelvin.jpl.nasa.gov writes: > ... > After flybys of Venus (twice), Earth and Jupiter as it loops >around the sun to pick up energy, Cassini will arrive at Saturn >in November 2004, beginning a four-year orbital tour of the >ringed planet and its 18 moons. The Huygens probe will descend to >the surface of Titan in June 2005. Pardon my asking an ignorant question, but I can't understand why it should take 7 years to get to Saturn. When Voyager went to Jupiter and Saturn, it took (if I recall correctly) 4 years and a Jupiter flyby to make it to Saturn. Here, you are using 4 flybys, and it's taking you 7 years! I would think that if you were to adjust the launch date so that Jupiter and Saturn were in the same relative positions as they were in 1977 (when Voyager was launched), you could do the same trick again (in the same 4 years). Thanks for your help. HAyim Hendeles ------------------------------ Date: 11 Dec 92 00:04:32 GMT From: Miroslaw Kuc Subject: Earth Movie Newsgroups: alt.sci.planetary,sci.space In article <1g4utkINNaha@transfer.stratus.com> det@phlan.sw.stratus.com (David Toland) writes: >In article <1992Dec8.131618.13405@aio.jsc.nasa.gov>, tes@gothamcity.uucp > (Thomas E. Smith [LORAL]) writes... >>I have another question that maybe Ron Baalke can answer. Is Galileo going to >>take any footage of the lunar eclipse tomorrow? I think that would be an awesome >>short movie, and a once in a lifetime chance. > >Too bad it's not a solar eclipse. Footage of the moon's shadow crossing >the earth's surface would really be striking! > It is true, however, we get this from weather satelites! Miro -- wizard@r-node.pci.on.ca wizard@r-node.gts.org ------------------------------ Date: Fri, 11 Dec 92 17:14:21 EST From: 18084TM@msu.edu Subject: Jet Lag >>The big problem with >>transoceanic flight is that it would be much to expensive (and besides the >>jet lag would be awful :-). >I believe you have that backwards. My understanding is, the faster the >flight, the less the jet lag. Think about it. If you take a tramp steamer, the difference between your local time and POD time is very small, per unit of travel time, so you can catch up on the difference as you go. The faster you travel, the bigger is that difference, and the less time, during travel, you have to keep in-phase. That's why they call it 'jet-lag' instead of 'boat-lag' or 'horse-lag'. (Imagine the problems with tranporter-lag :-) -Tommy Mac -----------------------------============================================ Tom McWilliams | What a tangled web we weave, when at ". | 18084tm@ibm.cl.msu.edu | , .first we .practice .*' .| (517) 355-2178 -or- 353-2986| '. ' . . to decieve , | a scrub Astronomy undergrad | After that, the , + | at Michigan State University| improvement is tremendous! '. , .' | ------------------------------=========================================== ------------------------------ Date: Fri, 11 Dec 92 20:37:21 EST From: John Roberts Subject: liquid fuels -From: fcrary@ucsu.Colorado.EDU (Frank Crary) -Subject: Re: Cassini Undergoes Intensive Design Review -Date: 11 Dec 92 18:28:29 GMT -Organization: University of Colorado, Boulder -After the Challenger failure, NASA added a safety requirement that -nothing launched in by a space shuttle may use liquid fuels. That -means Cassini must use lower-energy solid rockets instead. I think you mean *cryogenic* fuels. Magellan, Galileo, and Ulysses all use liquid fuels. As I mentioned earlier, some of the post-Challenger Shuttle safety rules are being relaxed (following intensive review, of course). Perhaps this rule will eventually be one of them. Henry has indicated he would favor such a change. John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: Fri, 11 Dec 1992 00:27:26 GMT From: "Rich (the Wiz" Subject: Mach 8+ Space/Spy Plane? Newsgroups: lcc.junk,sci.aeronautics,sci.space My wife heard a snippet of an interesting news story late last week... Apparently reported in some English Aeronautic Journal was a story claiming that the US has a new spy plane capable of Mach 8+ (at least) in test. Apparently said plane has a glide path over Catalina while landing in Nevada. The story claimed that this plane was responsible for the periodic "mysterious sonic booms and window shaking" (Thursday mornings?) that have been occuring here in Southern CA. Anyone know anything more? -- Rich Silva Locus Computing Corporation rich@LOCUS.COM {uunet,ucivax,trwrb}!lcc!rich {randvax,ucbvax,trwspp}!ucla-se!lcc!rich ------------------------------ Date: 11 Dec 92 01:45:31 GMT From: Pat Subject: Orbit Question? Newsgroups: sci.space In article jbh55289@uxa.cso.uiuc.edu (Josh 'K' Hopkins) writes: >hdgarner@acs.harding.edu writes: > >[On the subject of statites (stationary satellites)] > >>Okay I understand what you are saying about the geo sync orbit, but what if the >>body you wanted to remain over one of the poles was able to produce its own >>electricity (i.e. very large solar array) which would be used to power ion >>thrusters to keep it in place? > >Ion thrusters still require fuel their just much more efficient than chemical >rockets. The only system that can stay stationary over long terms is a solar >sail. Nature may permit some neat tricks with magnetodynamic tethers but I >can't think of any that would work in this situation. > How about this. At the North pole, the lines of force are headed almost straight down and beaucoup charged particles are spiraling down. Could you set up a large circular superconducting lariat and gain impulse against either the magnetic field or the charged particles??? sorta like zubrins idea for a mag sail???? ------------------------------ Date: Fri, 11 Dec 92 21:00:05 EST From: John Roberts Subject: Presidential DC-1? -From: prb@access.digex.com (Pat) -Subject: Re: absolutely, positively overnight -Date: 11 Dec 92 19:01:00 GMT -Organization: UDSI -If the President used one, then you'd have to buy at least 4-5. -first there is the dual backup, so no terrorist knows which one he is in. -then the secret service would want one or two to fly escorrt, rigged out -with weapons, in case of alien hijackers. plus the press would need one. That seems to be the standard method for helicopter flights to Camp David (at least based on personal observation), but not for the 747(s) - the mode of flight is different. John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: Thu, 10 Dec 1992 19:07:09 GMT From: "Mitchell E. Gold" Subject: Profit in space activities (was: absolutely, positively overnight) Newsgroups: sci.space In article jbh55289@uxa.cso.uiuc.edu (Josh 'K' Hopkins) writes: > On the subject of expense, the Concorde seems a >good example. It's never been profitable enough to make anyone else want to >buy one and it's at least 1.5 orders of magnitude cheaper than I can see a DC >type vehicle being. So where's the motivation for passenger travel? The last I'd heard, the companies flying Concordes (British Air, anyone else?) had decided to write off the amount of money that was used in development of the aircraft, but the aircraft do make a good profit over operational costs. -- Mitchell Gold, sundance@rpi.edu ------------------------------ Date: 11 Dec 92 01:34:00 GMT From: wingo%cspara.decnet@Fedex.Msfc.Nasa.Gov Subject: Saturn history Newsgroups: sci.space In article , henry@zoo.toronto.edu (Henry Spencer) writes... >In article prb@access.digex.com (Pat) writes: >>>The first Saturn I flew on 27 Oct 1961, actually. >> >>So if the Saturn I was ready in 61, why didn't they use it for >>Gemini? > >The test flights needed to make it ready (by von Braun's standards) covered >the next several years. For one thing, the first few flights had no upper >stage and were incapable of making orbit. >-- This is very true and also what Von Braun wanted to do with the Saturn V. They wanted to fly the Saturn first stage, the two stages, etc.... The success of the Saturn IB flying the SIVB Saturn stage allowed them to do what they called "full up" testing, where the launched the full stack on the first SV flight. By the way the Saturn I had a perfect record, 28 launches and no failures. Also a thing of note is that the Centaur was originally designed and flown on the Saturn I as the upper stage. Dennis, University of Alabama in Huntsville. ------------------------------ Date: Thu, 10 Dec 1992 15:23:52 GMT From: Ben Burch Subject: Scud Missile technology Newsgroups: sci.space In article Lawrence Curcio, lc2b+@andrew.cmu.edu writes: >Anyway, the most amusing part was that he claimed the missile was >programmed through the medium of *paper tape*. It's amazing they got any >of those things off the ground :) Now, just a minute! It is really easy, sitting here in front of our megapixel GUI workstations to think that electromechanical computing is a failed technology, but in reality it was a quite robust and well implemented technology. It was neither as small, fast, or reliable as modern microelectronics, but it worked, and worked well enough for many applications, missiles being one of those. If one designs one's control laws around the basic speed of the machine, a missle generally does nothing that requires intense computation or rapid response. One assumes that the trajectory is pre-planned, and that anything on the missile requiring rapid feedback is handled by analog computers. ( Yes, I saw the smiley, but I couldn't resist. ) -Ben Burch ------------------------------ Date: Fri, 11 Dec 1992 06:00:57 GMT From: Frank Crary Subject: Scud Missile technology Newsgroups: sci.space In article <1992Dec9.144425.21026@lmpsbbs.comm.mot.com> dennisn@ecs.comm.mot.com (Dennis Newkirk) writes: >Scud B Specs: 11.5 m by 84-90 cm., weight 6370 kg., storable liquid >propellants, inertial guidance, range 280-300 km, nuclear-chemical- >HE warheads at 770-860 kg... The Sucd missiles used by Iraq against Saudi Arabia and Israel had been modified, sacrificing payload and structural integrety for range. I think the ranges of these modified missiles went up to ~500 km, and the payload was well under 500kg. They also had a demonstrated habit of braking up in mid-air... Aviation Week had a number of articles on the subject, during and just after the war. I believe there was also a multi-stage version (e.g. a cluster of scuds acting as a first stage and a single scud as the second stage) which was tested once, a few months before the invasion of Kuwait, but never used otherwise. Frank Crary CU Boulder ------------------------------ Date: Fri, 11 Dec 1992 00:46:09 GMT From: Rich Kolker Subject: Shuttle replacement Newsgroups: sci.space.shuttle,sci.space In article <4074@phred.UUCP> petej@phred.UUCP (Peter Jarvis) writes: >In article <1992Dec2.015805.4724@nuchat.sccsi.com> rkolker@nuchat.sccsi.com (Rich Kolker) writes: >> >>..... The Saturn V at MSFC is the Engineering >>test model, not a flight article. >Rich, I assume you mean the one at the Space and Rocket Center. There >isn't one at MSFC. :-) > >Peter.......... You got me. Of course SRC is built on land donated by MSFC, which is on land that was part of the Redstone Arsenal.... By the way, the Saturn V at JSC is the last item brought to JSC on thre barge canal before they filled it in. By the way, my LATEST information (from Space News Roundup, the JSC newspaper) is that it was Apollo 18's bird. Now I don't know who to believe. >>------------------------------------------------------------------- >> rich kolker rkolker@nuchat.sccsi.com >> It's been a long, long time >>-------------------------------------------------------------------- > ------------------------------ Date: Fri, 11 Dec 92 20:24:21 EST From: John Roberts Subject: Shuttle thermal tiles -From: loren@pixar.com (Loren Carpenter) -Subject: Re: what the little bird told Henry -Date: 11 Dec 92 18:36:00 GMT -Organization: Pixar - Pt. Richmond, CA USA ->>BUT: if the main place where NASP materials seem to be being used is ->>the heat shielding, and its re-entry temperature is lower than the ->>shuttle's, wouldn't shuttle re-entry materials be just as useful? - Indeed. I have an engineering sample of the white tile material. - It has a color, density, hardness and stiffness similar to a fine - grained foamed chalk. At first it seems like a smooth styrofoam, - firm and warm, but little white dust particles flake off as you - handle it. It would be easy to stick a pencil clear through a tile, - though it would probably crack. A moderate hailstorm would require - replacing all of them. I don't think it's quite as bad as it sounds - the outer surface has a hard coating. Also, I understand much of the Shuttle surface (presumably the upper surface) is now covered with some sort of "thermal blanket" rather than the tiles. Inspecting tiles on the DC-1 would probably be a nuisance in terms of its expected low maintenance requirements, but it seems to be only a small fraction of the maintenance effort required by the Shuttle - I think they normally just run a visual check, which might take a day or two. From listening to post-flight briefings, I gather that losing two or three tiles to runway debris might be considered typical. The Shuttle launch towers have movable covers which protect the orbiter from damage by hail and severe storms. It's interesting to recall the extreme concern over the thermal tiles before STS-1. Many people were convinced that the tiles would all fall off during reentry. (The fact that Enterprise lost many of its tiles during transport, and that Columbia lost some off its engine covers during launch added to the concern.) Now it seems to be treated as a solved problem (except for the weight, of course, and the inability to fly the Shuttle through rain during landing). I got to play with some Shuttle tile replicas at the Technology 2002 conference - they're being promoted as a solution to some Earth-based problems. Speaking of thermal protection - I saw some video taken on the flight deck during reentry - if you look out the front windows on the way down, you see a bright orange glow. John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: 11 Dec 92 04:53:14 GMT From: Philip Young Subject: Terminal Velocity of DCX? (was Re: Shuttle ...) Newsgroups: sci.space (Edward V. Wright) writes: |> If that's true, a supertanker must also push the edge of the envelope. |> But, of source, that's absurd. Tell that to the Spaniards 8^} -- Philip R. Young | Sir Lloyne might rib his friends, Data General Australia Pty. Ltd. | but he always gets in for his chop. ------------------------------ Date: Fri, 11 Dec 1992 00:41:12 GMT From: Phil Fischer Subject: WFPC-2 Will Magnify Hubble's Views of the Universe Newsgroups: sci.space,sci.astro In article <1992Dec10.213230.22518@elroy.jpl.nasa.gov> baalke@kelvin.jpl.nasa.gov writes: > With its corrective optics, scientists expect the telescope >will be able to provide the highest sensitivity to detect objects >10 times fainter than those visible from Earth-based telescopes, >with about 10 times greater spatial resolution. > ### I don't want to offend anyone, but this is simply not true. It might have been true if the HST was launched in the early 80s as originally planned. Ground-based telescopes (CFHT) can routinely acheive resolution (seeing) of 0.4 arcsec. Keck should be able to go deeper than HST, and the new Gemini telescopes should also go deeper and achieve better seeing than CFHT. Time has eroded much of the original advantages of the HST. However, there are still some projects that remain the exclusive domain of the HST, mainly those to do with very high resolution but not excessively faint. Phil -- Phil Fischer | Hamilton, Ont. fischer@crocus.physics.mcmaster.ca | Canada Dept. of Physics and Astronomy | L8S 4M1 McMaster University | 416-525-9140 X 4574 ------------------------------ Date: Thu, 10 Dec 1992 23:44:59 GMT From: Brad Whitehurst Subject: what the little bird told Henry Newsgroups: sci.space In article <1992Dec10.192026.16340@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes: >In article henry@zoo.toronto.edu (Henry Spencer) writes: >>In article pgf@srl03.cacs.usl.edu ("Phil G. Fraering") writes: >>>BUT: if the main place where NASP materials seem to be being used is >>>the heat shielding, and its re-entry temperature is lower than the >>>shuttle's, wouldn't shuttle re-entry materials be just as useful? >> >>They'd probably work as well, but there is a durability problem. Having >>to inspect every last damned tile is the last thing you want to do for a >>vehicle that's supposed to have rapid turnaround. > >They're also heavy as I recall, something you don't need in a SSTO. >I appreciated the summary you gave earlier, Henry. It looks like they >have a better test program planned than what has been outlined here >before. I still think their schedule is extremely optimistic and >success oriented, but we'll see. > >Gary Actually, as I recall, the tiles themselves are featherweights. Now, the backing and mounting system may add more weight than one would wish.... Actually, if the NASP material efforts pan out, it would give all aerospace/launcher efforts new material options, especially for load-bearing, high-temp skins and structures. One prob with the Shuttle scheme is that the tiles don't bear any structural load (that I recall). So you have two (at least) skins...one structural and one thermal. If the two functions can be combined in one structure, it could save considerable weight. Another reason to keep working on NASP! I just wish NASA had the money to do it...it's their kind of thing...out at the edge of development, but it has become dominated by the Air Force, since they are paying for it. NASA security is bad enough, but DoD is a royal pain, especially for academic research. -- Brad Whitehurst | Aerospace Research Lab rbw3q@Virginia.EDU | We like it hot...and fast. ------------------------------ End of Space Digest Volume 15 : Issue 535 ------------------------------