Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from beak.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, 16 Nov 1990 01:36:58 -0500 (EST) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Fri, 16 Nov 1990 01:36:17 -0500 (EST) Subject: SPACE Digest V12 #557 SPACE Digest Volume 12 : Issue 557 Today's Topics: Re: New Shuttle Engines The Ariane V36 failure Re: The great light bulb debate Re: LNLL Inflatable Stations Re: LLNL Astronaut Delivery Re: New Shuttle Engines Re: Name for LLNL station. Re: The Ariane V36 failure (was Re: Ariane launches ON TIME! (again)) Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription notices, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 13 Nov 90 19:05:28 GMT From: snorkelwacker!usc!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo!henry@bloom-beacon.mit.edu (Henry Spencer) Organization: U of Toronto Zoology Subject: Re: New Shuttle Engines References: <10948@milton.u.washington.edu> Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu In article <10948@milton.u.washington.edu> brettvs@blake.u.washington.edu (Brett Vansteenwyk) writes: >Not long ago it was noted that the first of Endeavour's engines had arrived >at KSC. Some mention was made that these engines were "new and improved". Don't read too much into this. There has been no major design change, just a bunch of small incremental improvements. >[1].Are these new engines useable in the older shuttles? ... Yes. >[2].Are these engines part of a more "mature" system? In other words, has >there been a batch of changes made to the manufacture/design of these "new" >engines that will improve their servicability and ease of refurbishment? That's the hope. Considering the magnitude of the failure to meet the original targets in these areas, there is room for a lot of improvement. >This engine has been in use for almost 10 years, and it would seem >that it could be classified as a "mature" system by now--a learning curve >with subsequent reduction in refurbishment costs as well as a more reliable >engine. Is there evidence to indicate that this has happened? ... Well, maybe some. The thing you learn from the learning curve in this case is really "these things will never be wonderful without major redesign". >[4].Whenever I see any discussion about new launcher development, I never, >or almost never see any suggestion to using the SSME's, nor do I see any >indication of an engine derived from SSME technology. The tendency is >to discuss systems originating 25 or even 30 years back. I am assuming >that the SSME was the most recent major engine development. Has all the >time and talent spent to make the SSME work been wasted on what is now >considered an evolutionary dead-end? ... Very nearly. The Japanese decided to adopt a similar approach (although a from-scratch design) for their H-2 booster, and are now regretting it. Most everyone else proposing new launchers wants to use less ambitious and more dependable engines, either old ones or new developments. The SSME concept wasn't bad in principle, and maybe it is the wave of the future if you're patient enough, but making it work well seems to be exceedingly difficult today. Certainly the SSME itself shows no signs of ever becoming particularly cheap. >[5].If not the evolutionary dead-end as postulated in [4], could there be >an SSME derivative for an expendable launcher... The definitive Shuttle C proposal wanted to use life-expired shuttle engines in an expendable launcher. The Hughes/Boeing Jarvis proposal also used expendable SSMEs, after they tried very hard to come up with a viable scheme for reviving the F-1 and J-2 and couldn't make it work. The SSME is just too expensive to be a good expendable engine, though. -- "I don't *want* to be normal!" | Henry Spencer at U of Toronto Zoology "Not to worry." | henry@zoo.toronto.edu utzoo!henry ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 12 Nov 90 01:43:42 GMT From: van-bc!rsoft!mindlink!a752@ucbvax.Berkeley.EDU (Bruce Dunn) Organization: MIND LINK! - British Columbia, Canada Subject: The Ariane V36 failure Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu > lvron@earth.lerc.nasa.gov writes: > > [commenting on a report that a piece of cloth in a water-line to an engine > caused the Ariane V36 failure on February 22] > > I've never been part of a failure investigation (thankfully ;-)) since I > joined NASA, so I don't know much about the procedure. I hope someone can > offer insight on the following questions: > > (1) the failure was due to a piece of cloth. How could this have been > isolated after the failure? > (2) what is the mechanism by which a piece of cloth was able to cause the > failure? By that I mean > - was the cloth of sufficient size/porosity to totally restrict water > flow? or did it have to be? > - how is a piece of cloth able to be in the water line anyway? > - what is the sequence of events leading to the failure, given the > presence of the cloth? > (3) how can Arianespace ensure no repeat of this mechanism/sequence of > events? > The following information, abbreviated from 3 issues of Spaceflight, may be of interest. May, 1990: The Ariane V36 Inquiry Board has presented its findings. They identify a blocked water line as the cause of the accident. The launcher exploded shortly after its launch on February 22. ... The loss of the mission was due to the decrease in thrust of one of the four Viking V motors on the first stage. The drop in thrust occurred 6.2 seconds after motor ignition. It was due to an almost total obstruction of the water feeding circuit of Viking motor D. The engine itself is not at fault. The obstruction occurred upstream of the motor before the water pump. The precise cause of the obstruction is either a foreign object in the pipe or a failure of the main water valve. [The article goes on to talk about how debris from the exploded launcher fell at the shoreline and just off-shore of the launch site.] A search of mangrove swamps in zone 2 located some 350 different objects from the first, second and third stages. In particular, this search located external tubing of engine D as well as water tank elements. The first stage propulsion bay along with the four Viking motors was found. Despite extremely difficult conditions, the suspect elements of the water circuit were recoverd shortly before this issue of Spaceflight went to press. June, 1990: The loss of Ariane V36 was caused by a small piece of cloth that blocked the water supply to one of the vehicle's first stage engines. ... The rag was probably left in the pipe when the tubing was dismantled and readjusted during first stage integration before transfer to French Guiana. Arianespace Chairman Frederic c'Allest said the cause of the failure was "not only shocking but hard to accept." September, 1990: The investigation into the loss of V36 revealed that a first stage engine lost thrust because a small piece of cloth blocked a water pipe. In an unconnected incident a small fire broke out in one of the strap-on liquid boosters due to a fuel leak. From flight V37, the water line and the N2O4 feed line of each engine will be examined. The inspection will take place at Kourou, using a fibroscope type video camera with integrated light source. ... Additional leak checks were made on the first stage and strap-on fuel lines to ensure that there was no repeat of the fire on the previous mission. Also, new thermal protection inside the propulsion bays of the first stage will protect electrical systems in the event of a fire. Spaceflight is an excellent journal received by members of the British Interplanetary Society. Address: 27/29 South Lambeth Road, London, SW8 1SZ, England. My understanding is that as the engine lost thrust, the remaining engines gimbeled to correct for the thrust imbalance. When the running engines reached the end of their gimbel limits the vehicle could no longer be kept on course, and in effect started to skid sideways through the air. Breakup due to aerodynamic forces followed shortly. What I have not been able to find out is why Viking engines need a water supply. This is presumably for cooling, however I have never heard of an engine that used anything other than its own propellants as a cooling source. Can someone familiar with the Viking engine explain the function of the water, and what happens when its supply is interrupted. -- Bruce Dunn Vancouver, Canada a752@mindlink.UUCP ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 13 Nov 90 17:26:42 GMT From: att!cbnewsl!moss!feg@ucbvax.Berkeley.EDU (Forrest Gehrke,2C-119,7239,ATTBL) Organization: AT&T Bell Laboratories Subject: Re: The great light bulb debate References: <9011092213.AA05755@cmr.ncsl.nist.gov>, <1990Nov13.035815.10203@zoo.toronto.edu> Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu In article <1990Nov13.035815.10203@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >In article <9011092213.AA05755@cmr.ncsl.nist.gov> roberts@CMR.NCSL.NIST.GOV (John Roberts) writes: >>The "inert" gas usually cited in the literature is nitrogen. Why would >>krypton be better than argon? > >Nitrogen is not really inert when temperatures get high. For example, >if you burn titanium in air -- 80% nitrogen, 20% oxygen, roughly -- the >ash is about 80% titanium nitride and 20% titanium oxide. For applications >involving incandescent metals, you want something that is really inert. >(If you're being really picky, the noble gases [the preferred modern term] >are not really inert either, but under these conditions they qualify.) > >Krypton is better than argon for the same reason that argon is better than >vacuum: the denser gas slows the evaporation of the tungsten filament. And because of the slower evaporation there is another advantage: The tungsten filament can be operated at a higher temperature; these bulbs are significantly brighter. Halogens (usually pure iodine) are still better (although a different process is taking place). But now, due to the high temperatures being reached, quartz glass must be used for the envelop. This is expensive and their applications become more specialized, such as automobile headlights, photography, etc. Forrest Gehrke feg@moss.att.com ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: Tue, 13 Nov 90 16:42:45 -0500 From: "Allen W. Sherzer" To: space+@andrew.cmu.edu Subject: Re: LNLL Inflatable Stations Newsgroups: sci.space In-Reply-To: <2687@exodus.Eng.Sun.COM> References: <7154@hub.ucsb.edu> <9011122154.AA02573@iti.org> Organization: Evil Geniuses for a Better Tomorrow Cc: In article <2687@exodus.Eng.Sun.COM>: >> [LLNL Earth Station will require fewer crew changes because >> they provide artificial G] >Soviet crews have stayed in orbit for over a year. They have demonstrated >that with advanced exercise machinery and lots of exercise it is possbile >to return to the Earth after a year in a 0g environment and completely >recover. True but they don't do it as a matter of routine. In a staion with artificial gravity crew endurance is not limited by microgravity. All things being equal a crew in the LLNL Earth Station will not need to be rotated as often as Freedom. Since it will cost several hundred million $$ to do a rotation, this is a major consideration. Allen -- +---------------------------------------------------------------------------+ |Allen W. Sherzer| I had a guaranteed military sale with ED-209. Renovation | | aws@iti.org | programs, spare parts for 25 years. Who cares if it | | | works or not? - Dick Jones, VP OCP Security Concepts | ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 12 Nov 90 18:05:04 GMT From: sdd.hp.com!samsung!umich!umeecs!msi.umn.edu!cs.umn.edu!sialis!orbit!pnet51!schaper@ucsd.edu (S Schaper) Organization: People-Net [pnet51], Minneapolis, MN. Subject: Re: LLNL Astronaut Delivery Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu Why not let the free-flyer be the one to orbit without the thruster corrections, except for the ones necessary to maintain orbit, let the manned platform do the formation flying? That may turn out necessary for Freedom as ell to have the materials sciences on a separate platform - an expanded Columbus, and let the manned platform do the biological experiments and have the SEI and OMV's to service the Columbus and EOS platforms. Perhaps an LLNL spun section could be added to the station. Even sent up first to house astronauts for construction phase? Thoughts, as this is also problematic. Could Hermes be launched from an upgraded Titan IV (LRB's)? We could purchase some for crew transfer, freeing the aging shuttle fleet for what it does best. Zeitgeist Busters! UUCP: {amdahl!bungia, uunet!rosevax, chinet, killer}!orbit!pnet51!schaper ARPA: crash!orbit!pnet51!schaper@nosc.mil INET: schaper@pnet51.cts.com ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 13 Nov 90 22:33:43 GMT From: sdd.hp.com!wuarchive!rex!rouge!dlbres10@ucsd.edu (Fraering Philip) Organization: Univ. of Southwestern LA, Lafayette Subject: Re: New Shuttle Engines References: <10948@milton.u.washington.edu> Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu In article <1990Nov13.190528.5893@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: HS>in an expendable launcher. The Hughes/Boeing Jarvis proposal also used HS>expendable SSMEs, after they tried very hard to come up with a viable HS>scheme for reviving the F-1 and J-2 and couldn't make it work. The SSME HS>is just too expensive to be a good expendable engine, though. ? I was under the impression that the reason Jarvis was not built, in either 'incarnation,' was because of political reasons. After all, isn't the shuttle the most capable vehicle ever built? Phil ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 12 Nov 90 18:45:02 GMT From: sdd.hp.com!samsung!umich!umeecs!msi.umn.edu!cs.umn.edu!sialis!orbit!pnet51!schaper@ucsd.edu (S Schaper) Organization: People-Net [pnet51], Minneapolis, MN. Subject: Re: Name for LLNL station. Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu I. Freedom 2 II. Von Braun Station III. Base Camp Freedom II IV. Oz Zeitgeist Busters! UUCP: {amdahl!bungia, uunet!rosevax, chinet, killer}!orbit!pnet51!schaper ARPA: crash!orbit!pnet51!schaper@nosc.mil INET: schaper@pnet51.cts.com ------------------------------ Return-path: X-Andrew-Authenticated-as: 0;andrew.cmu.edu;Network-Mail Date: 13 Nov 90 18:54:58 GMT From: swrinde!zaphod.mps.ohio-state.edu!samsung!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo!henry@ucsd.edu (Henry Spencer) Organization: U of Toronto Zoology Subject: Re: The Ariane V36 failure (was Re: Ariane launches ON TIME! (again)) References: <1990Nov6.192118.6012@cc.ic.ac.uk>, <1990Nov9.145517.1891@cc.ic.ac.uk>, <1990Nov10.151130.29117@eagle.lerc.nasa.gov> Sender: space-request@andrew.cmu.edu To: space@andrew.cmu.edu In article <1990Nov10.151130.29117@eagle.lerc.nasa.gov> lvron@earth.lerc.nasa.gov writes: >(1) the failure was due to a piece of cloth. How could this have been > isolated after the failure? They pinned down possible causes based on the symptoms, and then went through the recovered debris very carefully, and found the cloth. >(2) what is the mechanism by which a piece of cloth was able to cause the > failure? By that I mean > - was the cloth of sufficient size/porosity to totally restrict water > flow? or did it have to be? I believe it was large enough and solid enough to completely block the line. We're not talking about 30-cm pipes here. > - how is a piece of cloth able to be in the water line anyway? Good question. Nobody knows for sure. The obvious possibility is some minor blunder during manufacturing. If that's the case, there is little hope that the person responsible will ever admit it. > - what is the sequence of events leading to the failure, given the > presence of the cloth? Water flow to one engine chokes off, chamber pressure and thrust in that engine drop, the other engines gimbal farther and farther to compensate, eventually they hit their gimbal limits and the booster starts to turn, and the attempt to fly sideways exceeds its structural limits and it breaks up. >(3) how can Arianespace ensure no repeat of this mechanism/sequence of > events? The usual: more care during manufacturing, more thorough inspections, and some managerial changes to clarify who's responsible for that water line (one company had hold of each end and nobody was in charge of the whole thing). -- "I don't *want* to be normal!" | Henry Spencer at U of Toronto Zoology "Not to worry." | henry@zoo.toronto.edu utzoo!henry ------------------------------ End of SPACE Digest V12 #557 *******************