Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from hogtown.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests) ID ; Fri, 26 Apr 91 02:01:29 -0400 (EDT) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Fri, 26 Apr 91 02:01:23 -0400 (EDT) Subject: SPACE Digest V13 #464 SPACE Digest Volume 13 : Issue 464 Today's Topics: Re: Saturn V and the ALS Space camp -- thanks for the resposes Re: Atlas Centaur bites the big one, 4/18 Re: Energia (was Re: Saturn V blueprints) Re: Saturn V blueprints Re: Shuttle Reliability (was: Re: Saturn V and the ALS) Re: Gas Guns and Tethers Re: Uploading to alpha Centauri Re: Saturn V blueprints Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription requests, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Date: 25 Apr 91 16:42:48 GMT From: mentor.cc.purdue.edu!noose.ecn.purdue.edu!en.ecn.purdue.edu!irvine@purdue.edu (/dev/null) Subject: Re: Saturn V and the ALS In article , gaserre@isis.isis.cs.du.edu (Glenn A. Serre) writes: > Not magically appear, I think NASA has been committing(sp?) resources > to the shuttle at the expense of other systems. Now that they can, we > have ALS! > > This last sentence isn't too clear. Are you saying that NASA can move > resources from the Shuttle to ALS developement? Not exactly, I'm sorry is I was not clear. I meant to say that there}i is a stirring of political will to look into cheaper alternatives to the shuttle. NASA has also shown some will by allocating some money to ALS. > > I think the stagnation of launcher technology is more of a refusal > of NASA to use anything other than the shuttle for launches. (Until > recently) > Air Force launch technology is pretty stagnant, too. I'd have to agree with > Henry that it's due more to the fact that all launches are operational. > I am uncertain by what you mean in the last sentance. I'll try to reply. Sure its *partly* due to that, but NASA has been pretty insistant that the shuttle be used a lot, and has booked flights for both military and civilian uses. I believe that NASA pressured a lot of military to sign on. In the post Challenger world, we are trying to find alternatives to the shuttle and see that we have long neglected disposible launchers. Another point is that there is such an over capacity of relatively expensive launchers in the world ($2000+ /lb) that until prices drop a lot, there probably will be no reason to bring in yet anxDother super-costly ($2000+/lb) launcher, and thus, more stag~rnation. > > *not* have to debug the design significantly. For example, we know the > > engines run reliably without serious combustion instability... and that > > is several years' development bypassed right there. > > BUT, engines could be made that burn less fuel and therefore lift > even more to orbit. Maybe rocketdyne could modify the F-1 to > bring it up to date. > > This is how we got the SSMEs. Increasing performance does not decrease > cost, nor does it increase reliability (neccessarily). The Saturn V could > lift plenty of weight (mass, whatever) to orbit: 265,000 pounds. > Okay, I see what you mean. The bonus that making it stronger/lighter is allowing even more to be boosted making the pound to orbit decrease to a reasonable level. I'll agree that 265,000 pounds is great, but if we could do better for similar costs, it would be worth looking into! (And, please don't claim that it would cause the costs to skyrocket, no one knows until it is technically examined in detaiL.) > > > >You just said that you'd need to revise the drawings and retest, etc. > > > > No I didn't. Please read what I wrote. We have to figure out how to make > > it again; we don't have to figure out what to make. > > > Unfortunately, this can be just as expensive. > > I disagree completely. The materials do NOT need to be made lighter. The > Saturn V worked as designed. The F-1 engines were low-pressure, high-thrust, > and they worked reliably. Maybe if we had been building and using F-1s since > the Apollo days, they would now be somewhat improved, but we scrapped the > tried and true Saturn for the complex, high-performance Shuttle and its > SSMEs. > So what is the best solution : resurrect the F-1 technology or use Our current capability to make reliabile engines? You know, maybe there could be a program to drop launch costs below these really expensive per pound costs! I think that is the real enemy of would-be space utilizers! If launch costs drop, then perhaps more resources could be concentrated towards what we are going to do in space and less on how we are going to get there (and 'oh my ghod look at that bill!'). -- +-----------------------------------------------------------------------+ | Brent L. Irvine | These are MY opinions | | Malt Beverage Analyst | As if they counted...:) | +-----------------------------------------------------------------------+ ------------------------------ Date: 25 Apr 91 16:07:54 GMT From: oravax!harper@cu-arpa.cs.cornell.edu (Douglas Harper) Subject: Space camp -- thanks for the resposes I'd like to thank everyone who emailed me about Space Camp. Apparently email from this site isn't always reaching its destination. The responses were all very encouraging and helpful, and I appreciate them very much. My daughter will be going to Space Camp this summer. -- Douglas Harper harper@oracorp.com oravax!harper@cu-arpa.cs.cornell.edu Are there any David N. White, SFS or KCA alumni reading this? ------------------------------ Date: 25 Apr 91 08:58:57 GMT From: mcsun!ukc!icdoc!syma!nickw@uunet.uu.net (Nick Watkins) Subject: Re: Atlas Centaur bites the big one, 4/18 From article , by dlbres10@pc.usl.edu (Fraering Philip): > In article <1991Apr23.153252.2873@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >>Sounds like you didn't look back far enough. :-) Centaur's development >>was a memorable horror story, although it has been very reliable in >>recent times. Most memorably, *both* the maiden flight of Atlas Centaur, May 8,, 1962 (also my debut :-) ), *and* the maiden flight of Titan IIIE Centaur were failures. Former *may* be the spectacular explosion at end of Geoffrey Reggio's film Koyannisqatsi (sp?), it certainly *was* an Atlas Centaur exploding. Mariner 8 was also lost to an Atlas Centaur failure on 8 May 1971, but not an explosion. It has, as they say, been "the soul of virtue in its later years", but I was still rather glad to hear that CRRES was in orbit after the first commercial Atlas launch. Nick -- ------------------------------ Date: 25 Apr 91 17:02:04 GMT From: mojo!SYSMGR%KING.ENG.UMD.EDU@mimsy.umd.edu (Doug Mohney) Subject: Re: Energia (was Re: Saturn V blueprints) AIn article <10817@hub.ucsb.edu>, 3001crad@ucsbuxa.ucsb.edu (Charles Frank Radley) writes: >whether or not NASA "likes" to buy launches from other people >is moot. Federal law PROHIBITS NASA from purchasing foreign >launch vehicles. As Henry so eloquently pointed out, Congress could pass one-time exceptions to the "law" to allow NASA to purchase other launch vehicles. And if A) It saved money and B) Provided some "laundering" of financial aid to the Soviet Union, they'd do it in a New Yark minute. Signature envy: quality of some people to put 24+ lines in their .sigs -- > SYSMGR@CADLAB.ENG.UMD.EDU < -- ------------------------------ Date: 25 Apr 91 20:09:00 GMT From: mentor.cc.purdue.edu!noose.ecn.purdue.edu!en.ecn.purdue.edu!irvine@purdue.edu (/dev/null) Subject: Re: Saturn V blueprints In article <1991Apr25.174210.2349@iti.org>, aws@iti.org (Allen W. Sherzer) writes: > No this is on budget as well as schedule. Unlike other fighter > competitions this time the Air Force required significant buy > in by the contractors. Both where expected to put up about half > the development money. In fact, they may have come in a tad under > budget. They were 'expected' to do it because the Pentagon shorted the cash. Not any special contract agreement. Also, the Northrop time WAS 6 mo. ahead in completing the prototype, the Lockheed team was 1 year LATE (they asked for an extension and got it). > > Good engineers CAN estimate the cost of building things; even advanced > products. > I agree, but many times they aren't the ones making the schedule or budget. -- +-----------------------------------------------------------------------+ | Brent L. Irvine | These are MY opinions | | Malt Beverage Analyst | As if they counted...:) | +-----------------------------------------------------------------------+ ------------------------------ Date: 26 Apr 91 02:37:59 GMT From: agate!lightning.Berkeley.EDU!fcrary@ucbvax.Berkeley.EDU (Frank Crary) Subject: Re: Shuttle Reliability (was: Re: Saturn V and the ALS) In article <9104251625.AA25561@gemini.arc.nasa.gov> greer%utdssa.dnet%utadnx@utspan.span.nasa.gov writes: >This 97.4% figure for the Shuttle success rate is somewhat misleading. It's >really just a measure of how many times the Shuttle has launched without >blowing up. Just ask the people working on projects like Galileo, Astro, >HST, etc., etc., etc., how successful they think the Shuttle has been. If >we looked at how many items in all the planned manifests of the Shuttle were >successfully executed, how low would the success rate be then? Far below >50% I would imagine. Can anyone out there venture a guess? To quote the Office of Technology Assessment's _Round Trip to Orbit_ (OTA-ISC-419) "In 1988, a NASA contractor predicted post-Challenger Shuttle reliablity would be between 97 and 98.6% and used 98% as a representative estimate. A more recient NASA study of success on the Galileo mission would probably be between 1 in 36 (97.2%) and 1 in 168 (99.4%)." In an earlied study, OTA used 96% as an estimate, but said that the reliablity was almost certainly about 87% (e.g. a greater than 87% probability that the reliability wa above 87%). Frank Crary UC Berkeley ------------------------------ Date: 23 Apr 91 18:23:41 GMT From: ssc-vax!bcsaic!hsvaic!eder@beaver.cs.washington.edu (Dani Eder) Subject: Re: Gas Guns and Tethers In article <2753@ke4zv.UUCP> gary@ke4zv.UUCP (Gary Coffman) writes: > >Railgun, coilgun, gasgun, whatever, all are technically feasible for >small payloads that don't mind thousands of Gs. If you try to scale >them up to worthwhile payload size, or try to stretch them out for >reasonable G forces, then either the enviornmental problem of ground >level hypersonic shock waves, or the sheer physical size of the launcher >make them impractical. > >Tethers need to exceed the theoretical strength of materials limits by >orders of magnitude to work. Again, a fundamental scientific breakthrough, >not engineering R&D, needs to occur before tethers can become reality, if >ever. > The lower bound on accelerator g's can be found by considering the west slope of the island of Hawaii. There is a region of nearly constant slope approximately 20km long extending from about the 1 km altitude to approximately the 4 km altitiude. If a launcher has a muzzle velocity of 5000 m/s, then basic physics shows the acceleration required is a=v^2/2d=625m/s^2, or 63 g's. While this is more than people can stand, it is by no means 'thousands' of g's. As far as wothwhile payload size, I personally believe that I could do useful things with 10 kg payloads at a time, given some progress in the direction of 'brilliant pebbles', or very small spacecraft that have sensors and maneuvering capability. However, I have designed a gas gun that delivers 5 ton payloads at a time. Yes, the noise generated by a big hypersonic launcher is great. So is the noise generated by the space shuttle. Give me a similar 5 km clearance zone and the noise will be tolerable. On the subject of tethers, it is well known that the minimum mass tether is an exponential taper in cross section per 'scale length'. The scale length is the length under 1 g which can support it's own weight under 1 g. For Amoco performance products T-1000 graphite fiber, which has a tensile strength of 6895 MPa and a density of 1845 kg/m^3, the scale length under 1 g is 381 km. If we limit ourselves to an area taper ratio of 100, then we can\ dangle ln(100)=4.6 scale lengths of cable. This is 1752 km. The Earth's gravity well is 6375 km deep, thus we are 27% of the way there. The theoretical strength can be found from the work done in diamond anvil cells that reach extremely high pressures. The cells routinely reach pressures of over a megabar, or 1 million atmospheres. This is 15 times the strength of the graphite fibers. Thus there is plenty of room to reach a sufficient strength to do a simple tether. This ignores the fact that you do not have to have a tether all the way from orbit to the ground. A shorter tether hanging vertically in orbit will have it's lower end moving sub-orbitally. A launch system then only has to reach the bottom of the tether, rather than orbit. Anything that makes a launch vehicles' job easier is beneficial. The reminder of the ride to orbit (which is at the center of mass of the tether) can be via elevator. ------------------------------ Date: 25 Apr 91 13:50:56 GMT From: media-lab.media.mit.edu!minsky@eddie.mit.edu (Marvin Minsky) Subject: Re: Uploading to alpha Centauri Oh. Because of being on the NSS board of governors, we get to meet the Vice-president next week. Any suggestions about questions to ask him? (I can't promise to remember the answers, but I'll try.) (I would like to explain to him why Fred should be replaced by a station that is remotely-manned by telepresence from earth, but I expect my colleagues will try to kill me before I manage to make the point.) ------------------------------ Date: 25 Apr 91 21:01:56 GMT From: mojo!SYSMGR%KING.ENG.UMD.EDU@mimsy.umd.edu (Doug Mohney) Subject: Re: Saturn V blueprints In article <1991Apr25.174210.2349@iti.org>, aws@iti.org (Allen W. Sherzer) writes: > >>It was indeed done under fixed price contracts, of about $600M >>as I recall. However, apparently >both< prime contractors spent >>more like $1B each on the project. I don't know about the schedule, >>but they blew the budget significantly > >No this is on budget as well as schedule. Unlike other fighter >competitions this time the Air Force required significant buy >in by the contractors. Both where expected to put up about half >the development money. In fact, they may have come in a tad under >budget. You are incorrect. They put in MUCH more than half the development money. Maybe close to 75-80%. The losing contractor (as I previously mentioned and which you chose to ignore) lost lots of money, and the AF will not conduct business that way in the future, due to the disincentives of a "Winner Take All" approach. The long-term effects of this contract on our industrial base are unclear. >Good engineers CAN estimate the cost of building things; even advanced >products. This contract, and military "products" in general, is fundmentally different from a commercial good. The producers of the ATF have a locked-in monopoly; there is no 40/60 split of goods, as with certain second-sourcing of missiles. The winning contractor will recoup the expenses of his investment through selective bookkeeping and profits over the years, with no incentive to hold prices down, other than the threat of Congress cancelling/ordering fewer planes in the future. Using the military as an "example" of proper procurement and estimation is a VERY VERY poor example. I suggest you look up the cases of the C-5, B-1, and B-2. Oops, forget the A-12, but it was cancelled. Signature envy: quality of some people to put 24+ lines in their .sigs -- > SYSMGR@CADLAB.ENG.UMD.EDU < -- ------------------------------ End of SPACE Digest V13 #464 *******************