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, 23 Mar 90 01:45:48 -0500 (EST) Message-ID: Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Fri, 23 Mar 90 01:45:20 -0500 (EST) Subject: SPACE Digest V11 #179 SPACE Digest Volume 11 : Issue 179 Today's Topics: Re: Spacecraft on Venus Re: Shuttle Escapes Re: NASA Finds Major Flaw in Space Station Design Diesels/railguns Re: NASA Headline News for 03/21/90 (Forwarded) Mars Rover Update - 03/22/90 Re: Engineers Challenger Re: space news from Feb 26 AW&ST Mooney books Re: NASA Finds Major Flaw in Space Station Design Re: NASA Finds Major Flaw in Space Station Design ---------------------------------------------------------------------- Date: 22 Mar 90 17:32:38 GMT From: eugene@eos.arc.nasa.gov (Eugene Miya) Subject: Re: Spacecraft on Venus It is amusing for me to read the many technological "solutions" to the Venus heat sink electronics problem. However, just so you don't lose sight, you should look at Venus in perspective: 1) Everybody else is talking Mars missions. 2) There is a finite budget. This is a case of Einstein's The perfection of means and the confusion of aims seems to be our problem. This isn't to advocate massive space budgets. There are finite numbers of people who build, or launch, or control, or communicate. That is the dilemma of those planning missions. All part of the subtle dance of players who try to get these things done. Thoreau said The simplification of means and the elevation of ends is the solution. Another gross generalization from --eugene miya, NASA Ames Research Center, eugene@aurora.arc.nasa.gov resident cynic at the Rock of Ages Home for Retired Hackers: "You trust the `reply' command with all those different mailers out there?" "If my mail does not reach you, please accept my apology." {ncar,decwrl,hplabs,uunet}!ames!eugene Do you expect anything BUT generalizations on the net? [If it ain't source, it ain't software -- D. Tweten] ------------------------------ Date: 22 Mar 90 22:01:37 GMT From: skipper!bowers@ames.arc.nasa.gov (Al Bowers) Subject: Re: Shuttle Escapes In article <1990Mar19.185607.26093@helios.physics.utoronto.ca> neufeld@physics.utoronto.ca (Christopher Neufeld) writes: >In article <90Mar19.135002est.2709@ois.db.toronto.edu> hogg@db.toronto.edu (John Hogg) writes: >>However, a ``reasonably well protected human'' needn't wear a spacecraft. >>Station crew-escape systems have been proposed which amount to a >>spacesuit, a retrorocket pack, a heatshield, and a parachute. The >> > You mean this is a real idea??? I saw this described in the SF novel >_Orbital Decay_ by Allen Steele and brushed it off as a fabrication by >the author. This isn't as ludicrious as it sounds. there was a lot of work done in the early 1960's that showed this to be a very viable way to return from space. the real parameters of interest are what thermal environment can be withstood, the required wingloading and the reentry Mach number (velocity actually but everyone thinks Mach number any more). -- Albion H. Bowers bowers@elxsi.dfrf.nasa.gov ames!elxsi.dfrf.nasa.gov!bowers NASA Ames-Dryden Flight Research Facility, Edwards, CA Aerodynamics: The ONLY way to fly! Live to ski, ski to live... ------------------------------ Date: 22 Mar 90 13:54:36 GMT From: noose.ecn.purdue.edu!mentor.cc.purdue.edu!l.cc.purdue.edu!cik@iuvax.cs.indiana.edu (Herman Rubin) Subject: Re: NASA Finds Major Flaw in Space Station Design In article <1990Mar21.205532.21596@cs.rochester.edu>, dietz@cs.rochester.edu (Paul Dietz) writes: > In article <10880@hoptoad.uucp> tim@hoptoad.UUCP (Tim Maroney) writes: > >In article <1990Mar20.141224.7751@cs.rochester.edu> dietz@cs.rochester.edu > >(Paul Dietz) writes: < >>Yesterday's (3/19) NY Times reports that a NASA special < >>investigation team has concluded that the space station, as < >>currently designed, would require 2,200 hours of EVA per year < >>for repairs and preventive maintenance. This figure, which amounts < >>to about 2 EVAs per week, is described as "alarmingly high"; < >>an acceptable rate would be one per month. > > > >Two EVAs per week at 20+ hours per EVA? Eh? > > I screwed up; it's > 3 per week (with > 1 person, I think; the figure > is 2,200 person-hours). About an order of magnitude too much. > > Paul What can anybody expect? We know very little about the problems of space station construction and maintenance. We will have to learn much of it up there. True, we do have some information from the American and Russian small stations, but these have been small enough to have been sent up as a unit. If we cannot afford to have the equivalent of one person working a 40-hour week for EVA repairs and preventive maintenance, we are penny wise and pound foolish. We have to do our space engineering in space, not on earth. -- Herman Rubin, Dept. of Statistics, Purdue Univ., West Lafayette IN47907 Phone: (317)494-6054 hrubin@l.cc.purdue.edu (Internet, bitnet, UUCP) ------------------------------ Date: Thu, 22 Mar 90 08:27:11 CST From: steve@ncsc.navy.mil (Mahan) Subject: Diesels/railguns I know that this is getting rather far afield from Space, but the US Navy runs diesels in the 15K hp range. For example, the LSD-41 ship class uses two of these (v-16's) for main propulsion. They stand about 12 feet high, about 15 feet long, maybe 10 feet max width (from memory of a walkthrough). I have no idea the weight of these engines. Also, remember that piston engine output falls off as a function of available oxygen density (not considering super/turbocharging) and there's not a whole lot of air at 40K feet. As a Diesel relies on heat of compression for ignition and the ambient at this altitude is rather cool it may become a problem to sustain operation. I seem to recall that naturally aspirated gasoline engines produce about 50% of sea level horsepower at 15-20K feet and there is no reason to expect Diesel performance to be noticeably better. Using engine bleed air from a turbine engine REALLY hurts the performance of the jet. Turbocharging will help but I thing that further investigation should concentrate on other types of power plants (perhaps a turbshaft engine mounted in the slipstream driving a generator.) More random thoughts from: Stephen Mahan steve@ncsc.navy.mil Naval Coastal Systems Center Panama City, FL 32408-5000 ------------------------------ Date: 22 Mar 90 05:00:46 GMT From: bfmny0!tneff@uunet.uu.net (Tom Neff) Subject: Re: NASA Headline News for 03/21/90 (Forwarded) Gee, nothing about the NYTimes article. They're usually so *thorough*. Maybe they missed their paper delivery? :-) -- "Of course, this is a, this is a Hunt, you |*==| Tom Neff will -- that will uncover a lot of things. |===| tneff@bfmny0.UU.NET You open that scab, there's a hell of a lot of things... This involves these Cubans, Hunt, and a lot of hanky-panky that we have nothing to do with ourselves." -- RN 6/23/72 ------------------------------ Date: 22 Mar 90 16:49:50 GMT From: orion.oac.uci.edu!uci-ics!jarthur!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@ucsd.edu (Ron Baalke) Subject: Mars Rover Update - 03/22/90 Mars Rover Update March 22, 1990 Engineers at the Jet Propulsion Lab began tests last week on a prototype of a Mars rover vehicle, the first step step toward establishing a manned outpost on the moon and sending a manned flight to Mars. The Planetary Rover Navigation Test Bed Vehicle, nicknamed "Robby", is a self-navigating vehicle about the size of a small car that can pick up samples or manipulate tools and equipment with its robotic arms. The testing this week was to determine whether the rover can be made self-thinking so that it does not have to rely on human commands. The prototype's computer systems must be autonomous and self-navigating because commands sent from Earth at the speed of light takes 30 minutes to reach Mars. Initial tests went well, and plans are being made to move from the prototype to a fully operational production model of the planetary rover. The Exporation Technology program to develop the rover grew out of a study known as the Mars Rover Sample Return (MRSR), an effort to design a self-thinking machine to collect ground samples from Mars. Last October, JPL folded the 2 year old sample return effort into the Exploration Technology program so that the machine could be designed to do more than pick up ground samples, such as building a capsule on the moon in which astronauts could live in. $5 million is allocated to the rover itself and about $500,000 is devoted to the development of autonomous navigation. In response to Bush's call to go back to the moon, and from there on to Mars, JPL is drawning up plans to dispatch a series of robots to Mars. The first step is the launch of the Mars Observer in 1992 to measure the atmosphere and planetary surface of Mars to find possible landing and outpost sites. A Mars Observer II launch may aslo occur in 1996. The Global Network Mission, scheduled for launch in 1998, calls for two spacecraft to place 24 instruments at different sites to study Mars' surface. Some would be designed to last several years and would serve as meteorological stations. A mission to bring back Martian soil is scheduled for launch in 2001. The trip is dedicated to learning more about the planet's history and searching for signs of life. Soil samples would be returned to Earth by the year 2003. Another spacecraft will be launched to Mars in 2003 used to help support future manned missions to Mars. The spacecraft will bear a communications satellite to serve as an orbiting data relay link for future mission. The spacecraft will also carry a site reconnaissance orbitor to perform mapping, high resolution photography and radio science instruments. Ron Baalke | baalke@mars.jpl.nasa.gov Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov 4800 Oak Grove Dr. | Pasadena, CA 91109 | ------------------------------ Date: 22 Mar 90 21:56:49 GMT From: skipper!bowers@ames.arc.nasa.gov (Al Bowers) Subject: Re: Engineers In article <1537@amethyst.math.arizona.edu> hicksm@spock (Michael Hicks) writes: > For those of you who work as aero/mech engineers at one of > the NASA centers such as AMES, KSC, LEWIS, etc, could you > answer this following question for me please? > Approximately how many new engineers fresh out of school does > your center hire per year? Do openings come up year round or > are there certain periods when most of the hiring is done? > Pros and cons of your work? > If you can answer any of these questions, I'd be grateful. Here at Dryden we usually average 2 to 4 fresh outs per year. This is in the civil service, there are also a number of contractor jobs and their hiring rate varies depending on demand. Most of our slots go to coops that have worked here during their schooling, next are minorities. Congress controls alot of our hiring practices as does the upper managment. This is mostly a function of what management percieves as the correct complement to get the job done. Advantages are job stability, lots of responsibility real fast, exciting programs, a great deal of diversity and a fair degree of autonomy. The disadvantages are low (initial) pay, benefits are getting worse (as Congress and the public think we get it too easy), tolerating the diverse mix of people (getting stuck with a less than enthusiastic person in a critical area is a real pain), government schedules, beauracracy (although this is not as bad as most people think). -- Albion H. Bowers bowers@elxsi.dfrf.nasa.gov ames!elxsi.dfrf.nasa.gov!bowers NASA Ames-Dryden Flight Research Facility, Edwards, CA Aerodynamics: The ONLY way to fly! Live to ski, ski to live... ------------------------------ Date: Thu, 22 Mar 90 08:03:04 CST From: steve@ncsc.navy.mil (Mahan) Subject: Challenger It was just pointed out to me that most of the special Challenger plates being issued here in Florida have numbers starting with the letters 'ASH'. Guess the DMV wasn't as alert as they should have been. (no :-)) steve@ncsc.navy.mil ------------------------------ Date: 22 Mar 90 14:39:24 GMT From: pilchuck!seahcx!phred!petej@uunet.uu.net (Pete Jarvis) Subject: Re: space news from Feb 26 AW&ST In article <1990Mar21.023642.14862@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: > >Viktorenko and Serebrov return to Earth after 22 weeks aboard Mir [not >a long stay by Soviet standards, although it's nearly twice the US record]. > Nothing new here. Their record is 4.35 times our longest stay. We're not worried about it. Peter Jarvis.......... ------------------------------ Date: 22 Mar 90 18:18:49 GMT From: thorin!homer.cs.unc.edu!leech@mcnc.org Subject: Mooney books I'm trying to identify some books I read when I was a kid. The protagonist was named Matt Mooney; he lived on the moon and became a cabin boy on a space ship that visited Earth in response to the "invasion" of a Surveyor probe. I seem to recall there was an entire series of these. Can anyone help me out with author/title/etc.? I can't find them in Books in Print or our library's juvenile collection, but without a title, it's hard to be sure. Please respond by email. -- Jon Leech (leech@cs.unc.edu) __@/ ``There ain't hardly nothin' cuter nor a sleepin' baby tad lessen it's a pork chop'' - Churchy La Femme ------------------------------ Date: 23 Mar 90 02:02:28 GMT From: agate!headcrash.Berkeley.EDU!gwh@ucbvax.Berkeley.EDU (George William Herbert) Subject: Re: NASA Finds Major Flaw in Space Station Design In article <2016@l.cc.purdue.edu> cik@l.cc.purdue.edu (Herman Rubin) writes: >< >>Yesterday's (3/19) NY Times reports that a NASA special >< >>investigation team has concluded that the space station, as >< >>currently designed, would require 2,200 hours of EVA per year >< >>for repairs and preventive maintenance. This figure, which amounts >< >>to about 2 EVAs per week, is described as "alarmingly high"; > >What can anybody expect? We know very little about the problems of >space station construction and maintenance. We will have to learn much >of it up there. True, we do have some information from the American >and Russian small stations, but these have been small enough to have >been sent up as a unit. > >If we cannot afford to have the equivalent of one person working a 40-hour >week for EVA repairs and preventive maintenance, we are penny wise and >pound foolish. We have to do our space engineering in space, not on >earth. Firstly; given Russian experience with EVA's that's two people for six to eight hours EVA every other day [it's physically exhausting]. That's a significant amount of crew. And, to seal the coffin, NASA has no space suit that can be reused. They had been planning on using the Shuttle suits, which need something like a thousand man hours of repair work after every five hours of average EVA per flight. It's not that we can't necessarily run those EVA schedules, but it's going to difficult to return the suits to earth for repairs after each use :-) -george ------------------------------ Date: 23 Mar 90 02:21:38 GMT From: agate!headcrash.Berkeley.EDU!gwh@ucbvax.Berkeley.EDU (George William Herbert) Subject: Re: NASA Finds Major Flaw in Space Station Design In article <647@idacrd.UUCP> mac@idacrd.UUCP (Robert McGwier) writes: > > >This is incorrect. The KVANT modules, etc. are being brought up one >at a time as they are too large to be boosted all at once. > >They are facing EXACTLY the same problems we will be. I hope some >data sharing will happen. I fail to see the connection between KVANT, where the russians are flying additional cannisters up and attaching them via docking ports, still using completely internal wiring etc. and FREEDOM where we're planning on a>building a truss in space, b>running wiring and cables and pipes along it and c>having the majority of the systems exposed to vaccum, where both its difficult to fix and it's harder to design and build. ******************************************************************************* George William Herbert JOAT For Hire: Anything, Anywhere: My Price UCB Naval Architecture undergrad: Engineering with a Bouyant Attitude :-) ------------------------------------------------------------------------------- gwh@ocf.berkeley.edu |||||||||| "What do I have to do to convince you?"-Q gwh@soda.berkeley.edu |||||||||||||||||||||||||||||||||||||||| "Die."-Worf maniac@garnet.berkeley.edu |"Very good, Worf. Eaten any good books recently?"-Q ------------------------------ End of SPACE Digest V11 #179 *******************