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, 15 Mar 91 01:52:37 -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, 15 Mar 91 01:52:33 -0500 (EST) Subject: SPACE Digest V13 #269 SPACE Digest Volume 13 : Issue 269 Today's Topics: Re: Space Flight Acceleration Regimes Re: German conference highlights doubts about ESA's manned space plans Re: Space Profits Re: Thrust NASA Headline News for 03/12/91 (Forwarded) Re: O-Ring and Feynman Re: Gaia Arcjet Release (Forwarded) Re: Space Station 'Fred' Restructuring 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: 13 Mar 91 01:25:43 GMT From: elroy.jpl.nasa.gov!jato!vsnyder@decwrl.dec.com (Van Snyder) Subject: Re: Space Flight Acceleration Regimes Bunch of stuff about centrifugal acceleration compensating for linear acceleration deleted .... There have been SF stories about using condensed matter, i.e. neutronium, to create a gravitational field to compensate for high acceleration. Of course, the mass of this stuff is enormous, and adds to the crud you need to push around. Bob Forward at Hughes has written some more serious articles about using masses to level out the microgravity field, i.e. so the gravitational potential is the same to within nano-g's in a small volume, say a cubic meter or so. -- vsnyder@jato.Jpl.Nasa.Gov ames!elroy!jato!vsnyder vsnyder@jato.uucp ------------------------------ Date: 13 Mar 91 01:01:49 GMT From: zephyr.ens.tek.com!tektronix!sequent!crg5!szabo@beaver.cs.washington.edu (Nick Szabo) Subject: Re: German conference highlights doubts about ESA's manned space plans In article <16255@celit.fps.com> dave@fps.com (Dave Smith) writes: > >[I write] > >Or, if you prefer not to pay the $1,000,000++/hour cost of an EVA, you > >could make sure it works before you launch it. > > > >This is a screamer. What do you do at Sequent, Nick? Work in marketing? This is a screamer. :-) I work in testing, making sure our products work. Not to brag, but Sequent's main selling point is our quality statistics, such as up-time. Sequent repairmen are about as common as Maytag repairmen. :-) Even so, when needed they can do the job for about 1/20,000th the cost of our vaunted astronauts. Now back to the regularly scheduled space.flamefest. :-) -- Nick Szabo szabo@sequent.com "If you want oil, drill lots of wells" -- J. Paul Getty The above opinions are my own and not related to those of any organization I may be affiliated with. ------------------------------ Date: 7 Mar 91 18:54:50 GMT From: elroy.jpl.nasa.gov!sdd.hp.com!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!pitt!nss!Paul.Blase@ames.arc.nasa.gov (Paul Blase) Subject: Re: Space Profits >>Gold and silver in large amounts did >>not start flowing from America for nearly 50 years. "W> Exactly. No profit making enterprise would ever have funded the "W> colonization of the new world. Payoff time was just too long. "W> Under your system where every step must make buisness sense the "W> new world would never have been colonized. But every mission to the "New World" was funded with profit in mind. I think that we need to differentiate between "colonization" and "settlements". The first Spanish settlements were not self-sustaining communities, for the most part the men left their families in Spain. They came over with the express purpose of making as much money as possible (by exploiting and/or conquering the natives) and then going home. Later, the colonies were started, with farmers, families, etc. Most of these, by the way, were started for religous purposes or, similiar to Australia, as prison colonies. --- via Silver Xpress V2.26 [NR] -- Paul Blase - via FidoNet node 1:129/104 UUCP: ...!pitt!nss!Paul.Blase INTERNET: Paul.Blase@nss.FIDONET.ORG ------------------------------ Date: 12 Mar 91 14:01:59 GMT From: isis!isis!gaserre@uunet.uu.net (Glenn A. Serre) Subject: Re: Thrust John Roberts: Another method that has been mentioned is launching water from Earth, then using solar energy to convert it to hydrogen and oxygen for use in a conventional engine. Because of its greater density, the water should be much cheaper to launch than LOX/LH2. It might be possible to save even Me: I thought that the Space Station (Fred) was at one time going to use this scheme. Has this been abandoned? -- --Glenn Serre gaserre@nyx.cs.du.edu -- --Glenn Serre gaserre@nyx.cs.du.edu ------------------------------ Date: 12 Mar 91 17:46:31 GMT From: usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@ucsd.edu (Ron Baalke) Subject: NASA Headline News for 03/12/91 (Forwarded) Headline News Internal Communications Branch (P-2) NASA Headquarters Tuesday, March 12, 1991 Audio Service: 202 / 755-1788 This is NASA Headline News for Tuesday, March 12, 1991 Kennedy Space Center technicians powered up the Atlantis yesterday and are now carrying out the orbiter interface test. Today's activities include leak checks and the installation of a few outstanding thermal protection system tiles. The frequency response test is scheduled for tomorrow. Atlantis and its STS-37 stack are presently on a schedule which would support rollout of the mobile launch system to launch pad 39-B in the early morning hours of Friday, March 15. STS-37's payload, the Gamma Ray Observatory, was installed in the payload cannister last night and should be in the pad 39-B payload changeout room by daybreak tomorrow. GRO could be installed into Atlantis' payload bay by late this weekend. The terminal countdown demonstration test for STS-37 is scheduled for March 19 and 20. The STS-37 flight readiness review is currently set for March 26 and 27. KSC technicians expect to begin the demate procedures on the STS-39 stack today. Discovery's removal from the external tank should occur about 4:00 pm this afternoon. If the demate procedure goes smoothly, Discovery will be rolled back into the orbiter processing facility about 9:00 am Thursday, March 14. Columbia, still in the orbiter processing facility, is awaiting installation of the Spacelab habitable module for its STS-40 Spacelab Life Sciences mission. The module is presently in the Operations and Checkout Building and will be moved to the OPF next week for installation into Columbia's payload on March 23. * * * * * * * * * * * * * * * * The NASA honor awards ceremony takes place this afternoon at 2:00 in the Health and Human Services auditorium at 4th and Independence Avenue. Administrator Richard Truly and Associate Deputy Sam Keller will present 55 individual and 16 group awards. Noted author, historian, and Librarian of Congress Emeritus, Daniel Boorstin will address the group. * * * * * * * * * * * * * * * * The House Subcommittee on Technology and Competitiveness (Committee on Science, Space and Technology), and the House Subcommittee on Research and Development (Committee on Armed Services) today will hold a joint hearing on NASA's FY 1992 budget request for the National Aero-Space Plane. Participants will include NASA Deputy J.R. Thompson, and Dr. Allan Bromley, White House Science Advisor. The hearing is at 1:30 p.m. in the Rayburn House Office Building. The event will be videotaped for replay on NASA Select TV. * * * * * * * * * * * * * * * * On Thursday and Friday, March 14 and 15, the American Astronautical Society is hosting its 29th Goddard Memorial Symposium. The theme is "Humans and Machines in Space: The Vision, The Challenge, The Payoff," and focuses on the synergistic relationship between people and machines. Adm. Truly will deliver the keynote speech on Thursday. James Beggs will chair the session on "The Vision," J.R.JThompson will chair the session on "The Challenge," and Lt. General James Abrahamson will chair the session on "The Payoff." John Noble Wilford, New York Times science writer and two-time Nobel Prize winner, is the general chairman. The sessions led by James Beggs, J.R. Thompson, and James Abrahamson, and the keynote remarks by Adm. Truly will be videotaped for replay on NASA Select TV. Here's the broadcast schedule for Public Affairs events on NASA Select TV. All times are Eastern. NASA Select TV is carried on GE Satcom F2R, transponder 13, C-Band, 72 degrees W Long., Audio 6.8, Frequency 3960 MHz. Tuesday, 3/12/91 12:00 pm Starfinder program "Fusion Energy." 12:15 pm Stennis Space Center 1991. 12:30 pm History of Space Travel "Astronauts: U.S. Project Mercury." 1:00 pm The Infinite Voyage series, "Miracles by Design." Wednesday, 3/13/91 1:15 pm Magellan-at-Venus report live from Jet Propulsion Laboratory. ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |___ M/S 301-355 | Change is constant. /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | |_____|/ |_|/ |_____|/ | ------------------------------ Date: 13 Mar 91 01:51:27 GMT From: skipper!shafer@ames.arc.nasa.gov (Mary Shafer) Subject: Re: O-Ring and Feynman In article <1991Mar11.150257.28368@nstn.ns.ca>, roberts@Iris1.ucis.dal.ca (Greg Roberts) says: > >I have the most absolute respect for Feynman. He took at the technical mumbo >jumbo from the MT engineering staff, and made it crystal clear so that anyone, >including Neil Armstrong, could understand it. Temperature. O-Ring. Failure. And what the hell do you mean by "anyone, including Neil Armstrong, could understand it"? Is this a snotty little sneer at astronauts? You should be ashamed of yourself. Keep your inferiority complex under better control--just because you're not an astronaut, it's not necessary to insult those who are. -- Mary Shafer shafer@skipper.dfrf.nasa.gov ames!skipper.dfrf.nasa.gov!shafer NASA Ames Dryden Flight Research Facility, Edwards, CA 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: 10 Mar 91 05:57:28 GMT From: munnari.oz.au!metro!socs.uts.edu.au!dcorbett@uunet.uu.net (Dan Corbett) Subject: Re: Gaia lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall) writes: >In article <9103020230.AA06812@cmr.ncsl.nist.gov> roberts@CMR.NCSL.NIST.GOV (John Roberts) writes: >: What part of Gaia is its appendix? :-) >Hmm, something that uses resources but doesn't contribute to the good of >the whole, and is, in fact, occasionally destructive? I'll have to >think about that one... :-) Politicians? ------------------------------------------------------------------------------ Dan Corbett Department of Computer Science University of Technology, Sydney Sydney, New South Wales, Australia ------------------------------------------------------------------------------ ------------------------------ Date: 14 Mar 91 16:22:06 GMT From: elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@decwrl.dec.com (Ron Baalke) Subject: Arcjet Release (Forwarded) Sarah Keegan Headquarters, Washington, D.C. March 14, 1991 (Phone: 202/453-2754) Linda S. Ellis Lewis Research Center, Cleveland, Ohio (Phone: 216/433-2900) RELEASE: 91-39 ARCJETS YIELD BETTER PERFORMANCE, LONGER SATELLITE LIFE NASA's Lewis Research Center, Cleveland, has the lead role in developing the arcjet thruster technology recently selected for stationkeeping use on AT&T's Telstar 4 communications satellites. Arcjet systems offer a significant improvement in propellant use over chemical and other electrically-augmented thrusters. The savings realized can be used to increase a satellite's on-orbit lifetime or payload mass. Alternatively, launch mass can be decreased so that a smaller rocket booster can be used. The arcjet research and technology program at Lewis Research Center began in 1983. A major objective was to bring advanced electric propulsion to operational status. This included component research necessary to demonstrate the required performance, life and integration issues associated with the arcjet system. In an arcjet, a direct current electrical arc is used to heat the decomposition products of hydrazine propellant to very high temperatures. Although the arc core temperature can reach 31,123 degrees F, the nozzle walls are protected by a cool gas boundary layer. The hot, slightly ionized gas exits the rocket nozzle at an average velocity 1.5 to 2 times that attained in conventional thrusters. For example, the 1.8 kW arcjet systems developed by Rocket Research Co. (RRC), Redmond, Wash., for the Telstar 4 program, provide a specific impulse (thrust divided by the propellant consumption rate) of about 500 seconds. This compares to a state-of-the-art resistojet system (another type of electrical thruster) that would provide 300 seconds of specific impulse for the same task. The 1.8 kW design is modeled closely after a flight-type 1.4 kW system developed by RRC under a Lewis-sponsored program. Switching to arcjet systems for north-south stationkeeping on a geosynchronous communications satellite can reduce propellant requirements by several hundred pounds. This savings can extend satellite lifetime by more than 50 percent or allow the satellite to shift to a less powerful, less expensive launch vehicle. The arcjet technology developed by NASA's Lewis Research Center and U. S. industry is the most advanced in the world. The Telstar 4 thrusters are the only arcjets accepted for operational use on a spacecraft. Lewis and industry continue to study arcjet thruster systems and their interactions with host spacecraft systems. Results to date suggest that electromagnetic interference with satellite systems should be minimal and that there will be no problem sending radio signals through the thruster exhaust plume. Lewis researchers also are investigating a range of power options to enhance the versatility of hydrazine arcjet technology. Examples include low power (1 kW) systems for power-limited satellites and high specific impulse systems for advanced communications satellites. The use of high specific impulse hydrogen arcjet systems also is being explored for primary propulsion. ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@mars.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |___ M/S 301-355 | Change is constant. /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | |_____|/ |_|/ |_____|/ | ------------------------------ Date: 13 Mar 91 20:30:57 GMT From: rex!rouge!dlbres10@g.ms.uky.edu (Fraering Philip) Subject: Re: Space Station 'Fred' Restructuring Where can I get pictures of the new 'Fred' configuration? Phil ------------------------------ End of SPACE Digest V13 #269 *******************