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 ; Sun, 18 Nov 1990 02:34:43 -0500 (EST) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Sun, 18 Nov 1990 02:34:11 -0500 (EST) Subject: SPACE Digest V12 #571 SPACE Digest Volume 12 : Issue 571 Today's Topics: Re: Pity The Much Abused Shuttle Aviation & Space Weekly Alert (was Re: LNLL Inflatable Stations) Re: Pity The Much Abused Shuttle Re: LNLL Inflatable Stations Re: New Shuttle Engines Latest STS 38 orbital elements. Magellan Update - 11/16/90 Re: New Shuttle Engines Re: Magellan Update - 11/16/90 Ulysses Update - 11/16/90 Re: Summary of responses to "the Ariane V36 failure" (long - sorry) 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 ---------------------------------------------------------------------- Date: 16 Nov 90 22:52:07 GMT From: jtgorman@arizona.edu (J. Taggart Gorman) Subject: Re: Pity The Much Abused Shuttle In article <0093FCE4.EF209760@KING.ENG.UMD.EDU> sysmgr@KING.ENG.UMD.EDU (Doug Mohney) writes: >In article <658778464.bap@F.GP.CS.CMU.EDU>, Barak.Pearlmutter@CS.CMU.EDU writes > >Wrong Bbbbbuck. Shooting out the windshield on a jeep results in lots of glass >and maybe you might kill someone. If you're Rambo, you dive out of the jeep, >tastefully tuck-and-roll, then return fire. If the windshield of the shuttle >gets shot out, and you don't happen to be wearing a space suit, you suck >vaccuum. Should you be so fortunate enough to get into a space suit, >Ivan-the-Terrible has now boarded the shuttle to finish the job he started. Since this shuttle would knowingly be going into combat, all personel *would* be in 'suits, because depressurization would be the first thing mean 'ole Ivan would try. It looks like we're writing the script for Rambo VII, the one where the bad Russian space Colonel captures Rambo's one-and-only-friend-and-best-buddy and take him to his sekret nuklear space battle fortress. Since NASA doesn't want to waste a shuttle to save Rambo's one-and-only-friend-and-best-buddy, good 'ole Rambo sneaks into the evil USSR and steals a Russian shuttle (damn! forgot the name! "My mind is going......" - Hal & me) and on the way to the sekret nuklear space battle fortress, Rambo destroys all of the evil Russian space forces, and several TIE fighters. Sounds like a winning script to me! :) | John Taggart Gorman Jr. | "I'm a no rust build up man myself." | | -Christian Slater | jtgorman@caslon.cs.arizona.edu | in 'Heathers' ------------------------------ Date: 16 Nov 90 23:13:48 GMT From: mintaka!ogicse!unicorn!n8035388@bloom-beacon.mit.edu (Worth Henry A) Subject: Aviation & Space Weekly Alert (was Re: LNLL Inflatable Stations) In article <1990Nov16.163551.18376@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes: >In article <1266@iceman.jcu.oz> eempa@iceman.jcu.oz (M Parigi) writes: >> By the way, how does the need for EVA's compare to that of FREEDOM's? > >I would expect considerably less, because there is less external equipment. >My impression is that LLNL has gone in for putting things inside rather than >outside, permitting shirtsleeves maintenance on most of it. The Nov 12th issue of AvLeak has, among several interesting space related articles, a summary of the latest FREEDOM redesign goals, included: > The biggest single change is the elimination of the longitudinal truss and the associated EVA-intensive external experiments and other Orbital Replacable Units. > The modules will be tightly clustered and the solar & thermal radiator arrays will be mounted on a long trailing beam. > Besides reducing EVA requirements, this new configuration is expected to improve orbital stability and drastically reduce thruster usage. > Shuttle construction flights reduced to 18 (@ 4/yr) -- but still no interest in ELV's. First element in orbit is still planned for '95. > A restructuring of the project budget to something that may be more acceptable to Congress. Budget levels in $2.1-2.6B range with only small, if any, increases from yr-to-yr (Its at LOT easier to maintain a budget at the previous years level than to get a significant increase -- perhaps NASA management is finally starting to develop some political savvy, its only taken 30 yrs). > Changes to the project management structure are "off limits" (I suppose NASA feels that the optimal 'pork' distribution has already been achieved ;-) ). The Nov. 12th issue also has an article on the various non-USA hypersonic development projects: > The contenders include GERMANY-ITALY-SWEDEN, FRANCE, JAPAN and British Aerospace-USSR (with growing Brit. gov. interest) > Public interest in Seanger(sp?) has already been credited with producing a dramatic increase in engineering/science university enrollment in Germany. > The Japanese plan to progress from scratch, thru a 2-Stage-Stage-To- Orbit vehicle, to SSTO in 20 yrs! In a related note, the Nov. 5th issue has several articles on the USA hyperspace-plane combined design and a less-expensive, rocket based, SDIO proposed alternative. These two issues are well worth a visit to your local library or newstand. If you can't get hold of these issues, then stay tuned for one of H. Spencer's fine reviews in the coming weeks. ------------------------------ Date: 16 Nov 90 21:38:13 GMT From: newton.cs.jhu.edu!callahan@umd5.umd.edu (Paul Callahan) Subject: Re: Pity The Much Abused Shuttle In article <658778464.bap@F.GP.CS.CMU.EDU> Barak.Pearlmutter@CS.CMU.EDU writes: >One shot from a pistol could disable a Jeep. Yet for >some reason Jeeps are useful military vehicles. Perhaps because they are a bit cheaper than space shuttles (not to mention more numerous). It's just a guess... -- Paul Callahan callahan@cs.jhu.edu ------------------------------ Date: 16 Nov 90 06:40:08 GMT From: munnari.oz.au!mel.dit.csiro.au!yarra!melba.bby.oz.au!gnb@THEORY.TN.CORNELL.EDU (Gregory N. Bond) Subject: Re: LNLL Inflatable Stations >>>>> On 16 Nov 90 02:16:10 GMT, eempa@iceman.jcu.oz (M Parigi) said: [ re. external maintainence of a spinning space station ] eempa> You would have to either hook them on to something, or keep good hold of eempa> things. You would have little chance of retrieving something if it was eempa> dropped or came unhooked. Doing an EVA on the outside of the spinning eempa> platform would be like doing repairs on the outside of a building (you eempa> wouldn't want to fall) as compared to like doing a scuba dive on a eempa> nonspinning platform. A Small question of orbital mechanics: Say the maint crew is on the outside of the spinning station (replacing AE-31 units, whatever), and they drop a spanner. It "falls" away from the station at some speed (the rotational speed of the station at that point), and takes up an independent orbit around the earth. That orbit would be a slightly perturbed version of the station orbit, due to the (small) delta-v from the spinning station. Under what circumstances will the orbit of the station and the spanner intersect, and at what velocity would the collision happen (assuming no manouvering of the station)? My guesses: If, at the moment it is dropped, the velocity of the spanner wrt station is at rightangles (either plane) to the orbital velocity of the station, then spanner and station should meet twice per orbit. Parallel velocities and the spanner will move in or out and they won't meet. Inbetween, interpolate! Max collision velocity: (2x?) spanners' initial speed wrt station (i.e. very slow, as orbital collisions go). So are dropped spanners a serious hazard? Greg. -- Gregory Bond, Burdett Buckeridge & Young Ltd, Melbourne, Australia Internet: gnb@melba.bby.oz.au non-MX: gnb%melba.bby.oz@uunet.uu.net Uucp: {uunet,pyramid,ubc-cs,ukc,mcvax,prlb2,nttlab...}!munnari!melba.bby.oz!gnb ------------------------------ Date: 16 Nov 90 21:13:40 GMT From: usc!wuarchive!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!utzoo!henry@apple.com (Henry Spencer) Subject: Re: New Shuttle Engines In article <11236@milton.u.washington.edu> brettvs@blake.u.washington.edu (Brett Vansteenwyk) writes: >I am curious as to how much of a design difficulty it is to have an engine >operate (well or otherwise) at both sea level and in the vacuum ... It's not an enormously big deal, but it is a nuisance. Ignoring some details, one gets maximum thrust out of a given exhaust stream if it exits the nozzle at roughly ambient pressure. This means that a nozzle optimized for high altitude will be a good bit longer than a sea-level nozzle, to give the gas more expansion. An underexpanded nozzle, with the gas exiting at higher than ambient, results in some loss of thrust. A badly overexpanded nozzle causes the gas flow to break away from the nozzle wall before reaching the end, which causes all manner of nasty turbulence and problems of various kinds. The SSME nozzles are in fact mildly overexpanded for use at sea level, for the sake of performance at high altitude, but not enough to cause major trouble. Multiple stages, with upper stages ignited only at high altitude, offer somewhat of a way out of this. The first stage is still a compromise, because it finishes its burn in much thinner air than it started in, but the upper stages can use fairly uncompromised high-altitude nozzles. People have explored more devious schemes, like variable-length nozzles, but no real use has been made of them yet. >... If this is a heavy constraint, why light >the SSMEs at sea level at all ... One very important practical reason is that the #1 time for engine trouble is at ignition. Lighting the SSMEs on the pad means that the more benign kinds of engine failures simply cause a pad abort. There may also have been some hope that gimballing the SSMEs would suffice for control, and the SRBs wouldn't need gimballed nozzles, although in fact that didn't pan out. >By the way, I remember that there is some consideration (or ongoing effort) >to adapting the RL-10 to operate at sea level. Is this a good example of >this sort of design "difficulty"? In principle, all you need is a shorter nozzle, although you have to think about things like the effect on the cooling system. There may be some issues in ignition, too. -- "I don't *want* to be normal!" | Henry Spencer at U of Toronto Zoology "Not to worry." | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 16 Nov 90 21:13:34 GMT From: van-bc!ubc-cs!news-server.csri.toronto.edu!utgpu!molczan@ucbvax.Berkeley.EDU (Ted Molczan) Subject: Latest STS 38 orbital elements. Here are the first four STS 38 orbital element sets from NORAD: 1 20935U 90 97 A 90320.02911865 .00527620 15306-3 25599-3 0 28 2 20935 28.4678 243.5197 0006234 264.2180 21.9681 16.19915601 01 1 20935U 90 97 A 90320.04174710 .00000532 00000-0 73360-8 0 13 2 20935 28.4687 243.4563 0006495 267.8366 92.1432 16.20314645 19 1 20935U 90 97 A 90320.20017361 .00320873 40597-4 25599-3 0 39 2 20935 28.4683 242.1896 0037834 196.9133 7.8577 16.11416272 39 1 20935U 90 97 A 90320.40850694 .00161290 68898-5 25599-3 0 47 2 20935 28.4646 240.6373 0006560 286.7334 43.3613 16.02355418 67 The fourth set is the most current and reflects the manoeuvre to a higher orbit that was predicted by AV WEEK. The orbiter can be expected to manoeuvre to a slightly lower orbit, shortly after payload deployment, which is expected sometime today. Although we now have precise elements for the orbiter, there remains much for observers to do. The main task now is to try and observe the payload. If it is an imaging reconnaissance satellite, as reported by AV WEEK, and if past practice is followed, then it will remain in its deployment orbit for about 7 days, and then manoeuvre to its operational orbit. All shuttle and payload observation reports are welcome. -- Ted Molczan@gpu.utcs.utoronto.ca ------------------------------ Date: 16 Nov 90 23:33:53 GMT From: mintaka!think.com!sdd.hp.com!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@bloom-beacon.mit.edu (Ron Baalke) Subject: Magellan Update - 11/16/90 MAGELLAN STATUS REPORT November 16, 1990 The Magellan spacecraft is now performing nominally in mapping mode after experiencing its third loss-of-signal incident yesterday morning. It has just completed its 344th mapping orbit. Shortly after 9:00 AM PST yesterday, the spacecraft failed to return to Earth communications after the mapping pass of orbit #825. The S-band signal was reacquired about 40 minutes later, and signal level indicated that the high gain antenna was off Earth point by 1-1/2 to 2 degrees. The X-band signal required for radar data playback could not be acquired. Engineering telemetry indicated that the control system had detected a "heartbeat loss" similar to the incidents in August. The spacecraft had switched some components, such as the gyros and the Input/Output unit, but was continuing to execute its command sequence. The next three star calibrations were rejected because the one to three degree corrections would be greater than the limit set within the attitude control system. At 3:19 PM PST, attitude updates were sent to the spacecraft to correct the antenna pointing and mapping was resumed at 6:46 PM. The quick recovery from this loss of signal incident demonstrates the contingency plans which were developed as a result of the earlier incidents. In August, mapping was delayed for at least 15 days. Today, mapping was resumed after 9.75 hours, with a loss of only 3 orbits. Stephen Saunders, Magellan's project scientist, provided images and text for a special pictorial on Magellan to be published in the January Astronomy Magazine. ___ _____ ___ /_ /| /____/ \ /_ /| | | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov ___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov /___| | | | ___/ | |/__ /| M/S 301-355 | |_____|/ |_|/ |_____|/ Pasadena, CA 91109 | ------------------------------ Date: 16 Nov 90 17:59:07 GMT From: eagle!news@ucbvax.Berkeley.EDU (Dave Hall (Sverdrup)) Subject: Re: New Shuttle Engines In article <1990Nov14.071003.24567@cimage.com>, gregc@cimage.com (Greg Cronau) writes... > >I can understand why reviving the Saturn program would be damn near impossible, >but what problems were encountered with reviving just the F-1 engine program? In addition to lost documentation and tooling costs, two areas I am aware of are: 1) Air pollution. The F-1 burns LOX and kerosene, producing a smoky hydrocarbon exhaust. Not popular with environmentalists, especially in S. California where the Rocketdyne test labs are located. 2) F-1 production test facilities were located in the San Fernando valley (turbopumps at Rocketdyne/Santa Susana) and Edwards AFB (full-up engine tests). These facilities are way past the inactive stage - they have been either torn down or become completely derelict. You are talking 100's of millions of dollars (IMHO) to refurbish them. ------------------------------ Date: 17 Nov 90 01:46:10 GMT From: mintaka!think.com!sdd.hp.com!elroy.jpl.nasa.gov!wciu!abode!eric@bloom-beacon.mit.edu (Eric C. Bennett) Subject: Re: Magellan Update - 11/16/90 I guess this may be considered a 'dumb' question, but, what is the mission objective (other than the obvious, i.e. mapping Venus) of the Magellan spacecraft. In other words, what does the science community hope to learn by mapping Venus? Eric -- Eric C. Bennett uucp: {elroy|cit-vax}!wciu!abode!eric El Monte, Ca Internet: eric@abode.wciu.edu If you can read this you aren't looking through the hubble space telescope! ------------------------------ Date: 17 Nov 90 06:28:45 GMT From: uakari.primate.wisc.edu!sdd.hp.com!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@ames.arc.nasa.gov (Ron Baalke) Subject: Ulysses Update - 11/16/90 ULYSSES STATUS REPORT November 16, 1990 At the end of yesterday's science operations, a maneuver was performed on the Ulysses spacecraft to increase the spacraft's spinrate from 5 to 5.1 rpm and measure the effect on the nutation motion. The increased spinrate did slightly decrease the nutation, and further analysis will be required before any more actions are taken. Today's activities includes the switch-on of the Solar Wind Plasma instrument and a mode change on the Solar Wind Ion Composition instrument. ___ _____ ___ /_ /| /____/ \ /_ /| | | | | __ \ /| | | | Ron Baalke | baalke@mars.jpl.nasa.gov ___| | | | |__) |/ | | |___ Jet Propulsion Lab | baalke@jems.jpl.nasa.gov /___| | | | ___/ | |/__ /| M/S 301-355 | |_____|/ |_|/ |_____|/ Pasadena, CA 91109 | ------------------------------ Date: 17 Nov 90 19:55:39 GMT From: mentor.cc.purdue.edu!noose.ecn.purdue.edu!en.ecn.purdue.edu!dominop@purdue.edu (Philippos A. Peleties) Subject: Re: Summary of responses to "the Ariane V36 failure" (long - sorry) Could water injection into the combustion chamber have the same effect as that for jet engines, i.e., increasing the gas density? (I have seen something to this effect in the Rolls-Royce book "The jet engine" but I am not sure about the details since I don't have it with me). Philip Peleties -- I speak for myself, I think for myself, I work for myself ... but I don't want to play by myself ... so bring your toys and let's share ... ------------------------------ End of SPACE Digest V12 #571 *******************