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/usr1/ota/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr1/ota/space/space.dl) (->ota+space.digests) ID ; Mon, 9 Oct 89 05:25:56 -0400 (EDT) Message-ID: Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Mon, 9 Oct 89 05:25:27 -0400 (EDT) Subject: SPACE Digest V10 #128 SPACE Digest Volume 10 : Issue 128 Today's Topics: Re: Shuttle-Centaur The 'Face' of Mars Re: Shuttle-Centaur Re: Magellan summary? Re: Magellan summary? WANT ACTION IN WASHINGTON? WRITE A LETTER Re: What to do with the $30 billion (missions): A Plan Re: The 'Face' of Mars Re: NASA Headline News for 09/29/89 (Forwarded) Re: X-30, Space Station Strangles NASP ---------------------------------------------------------------------- Date: 6 Oct 89 14:10:14 GMT From: hsi!mfci!rodman@uunet.uu.net (Paul Rodman) Subject: Re: Shuttle-Centaur In article <1989Oct6.061712.22877@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >In article <1062@m3.mfci.UUCP> rodman@mfci.UUCP (Paul Rodman) writes: >>I heard the original plan had DUMP VALVES for the Centaur fuel (which >>put the craft over landing weight if you had to abort)! > >Yup. Most airliners with significant problems will dump fuel before landing >as well, for much the same reasons: reduced weight and reduced fire hazard. >What's the big deal? Weeeell, I don't know the facts the way you do Henry but what I was thinking was: - dump valves on airliners _are_ perceived as a small risk. Sometimes they leak or are deployed by mistake. Hopefully, the gain in safety is more. - An airliner dumps JP4. I presume the Centaur dumps potent fuel + oxidizer (not hypergolic I trust!). What is the probability of ignition in the presence of RCS thrusters, hot airframes, SRBs, considering that the reason for the dump is that something bad already happened to cause the abort? - You are awfully busy on a launch abort, are you going to allow a computer to decide when to dump? Yech. I'm not saying it can't (or shouldn't) be done, it just seems like more dicey scenerios are added to an already hazardous activity. Each shuttle is worth $1Billion, after all. Seems like the correct approach would be to have a Space tug (+ IUS on the probe too) to kick things out of earth orbit. Refuel the tug from unmanned tankers, please. Another way of looking at it is to observe that truckers, as a group, are doing something fairly dangerous compared to you or I. But _THEY_ consider the guys that drive the gasoline tankers to be really nuts..:-) pkr ------------------------------ Date: 4 Oct 89 15:25:25 GMT From: munnari.oz.au!csc!ccadfa!usage!basser!metro!ipso!runxtsa!clubmac@uunet.uu.net (Macintosh Users Group) Subject: The 'Face' of Mars Does anyone know about the 'face' on Mars? Apparently, a computer-enhanced image of a place on Mars revealed a humanoid face under layers of red dust. I don't know about you, but it would appear to me that the ideal way to leave a library behind for humanoids would be to have a face visible from orbiting spacecraft. I know it all sounds weird, but I just woke up with a dream about a library on Mars. 1:07am and off the planet... :-) _____________________________________________________________________________ | Jason Haines | | President, Club Mac - Australia's Largest Macintosh Users Group | | | | INTERNET: clubmac@runx.oz.au UUCP: uunet!runx.oz.au!clubmac | | ACSNet: clubmac@runx.ips.oz | |_____________________________________________________________________________| ------------------------------ Date: 6 Oct 89 21:14:11 GMT From: agate!shelby!portia!doom@ucbvax.Berkeley.EDU (Joseph Brenner) Subject: Re: Shuttle-Centaur So what was the problem with launching the Centaur dry and fueling it up in orbit? I read a Jerry Pournelle article some years back arguing for this approach (and actually, complaining that NASA was going to use the wet launch approach out of bureaucratic inertia). (My guess: You've got to boost the fuel somehow, and putting it in a different shuttle launch just moves the risk to another time. Boosting the fuel with an unmanned rocket might work but in those days NASA's policy was to do everything with the shuttle. Also, this gets back to the rendevous in orbit issue, which I gather is considered too tough by NASA, despite experience with Gemini, Apollo, Skylab and Apollo/Soyuz.) -- Joe B. (J.JBRENNER@MACBETH.STANFORD.EDU Materials Science Dept/Stanford, CA 94305) ------------------------------ Date: 6 Oct 89 23:09:12 GMT From: prism!ccoprmd@gatech.edu (Matthew DeLuca) Subject: Re: Magellan summary? In article <19250@ut-emx.UUCP> grads@emx.UUCP (Feulner ... Matt Feulner) writes: >In article <8910061757.AA10825@aristotle.Jpl.Nasa.Gov> pjs@ARISTOTLE-GW.JPL.NASA.GOV (Peter Scott) writes: >>Some trajectory wizard (who plainly >>deserves a medal, IMHO) discovered this bizarre track that enabled Galileo to >>reach Jupiter with the IUS booster. It's the most creative piece of mission >>planning I've seen since I started working here (<- this is called a hook). > >No doubt a grad student slave who never gets any credit. I'm >pretty sure it was a grad student who first realized the Grand >Tour/Voyager trajectory. > >Matthew Feulner You are quite correct; it was a grad student at CalTech by the name of Flandro who who came up with it. He is now a professor of aerospace engineering here at Georgia Tech; I had him for a course last year. As I recall, he did get some credit, at least locally; the Atlanta Journal-Constitution ran quite a piece on him at the height of the Neptune encounter. ------------------------------------------------------------------------------ Matthew DeLuca : Practice creates perfection Georgia Institute of Technology : Perfection creates power ARPA: ccoprmd@hydra.gatech.edu : Power conquers law ------------------------------------------------------------------------------ ------------------------------ Date: Fri, 6 Oct 89 10:57:16 PDT From: Peter Scott Subject: Re: Magellan summary? datapg!com50!questar!al@uunet.uu.net (Al Viall) writes: >Looking through the press release for Galileo, to which >I thank Peter Yee for sending through the net, I had read that the craft >would make a double earth flyby(i.e. the VEEGA track). >Why was this track chosen, considering that it would be more fruitfull to >just get the craft to Jupiter in one piece. >I am not bunking the experts at JPL and Ames, don't get me wrong, I am sure >they had there reasons, such as ' While it's out there, let's take advantage'. Uh, believe me, we wanted to. We planned to. We were going to, via the Centaur upper stage booster, until the Challenger accident, when it was decided that we really didn't want to run the SSMEs at 109% for longer than any other mission in order to launch a large bomb. Some trajectory wizard (who plainly deserves a medal, IMHO) discovered this bizarre track that enabled Galileo to reach Jupiter with the IUS booster. It's the most creative piece of mission planning I've seen since I started working here (<- this is called a hook). Peter Scott (pjs@grouch.jpl.nasa.gov) ------------------------------ Date: 6 Oct 89 17:18:21 GMT From: dptg!pegasus!psrc@rutgers.edu (Paul S. R. Chisholm) Subject: WANT ACTION IN WASHINGTON? WRITE A LETTER (I thought this might be of interest to the group.) (From the Personal Business section of BUSINESS WEEK, October 9, 1989, p. 172.) WANT ACTION IN WASHINGTON? WRITE A LETTER Every Day, tons of mail arrive on Capital Hill. But, despite all the time and attention that goes into handling it, nine out of 10 Americans never write their representatives or senators. Maybe it's a feeling that Washington is far away, captive of special interests, and out of touch with everyday concerns of people. Perhaps it's a feeling that, in this information-saturated age, the lawmakers are too busy to read their mail. But here's a secret: If you want action from Washington, write a letter. Keep it polite, and concise, but above all, personal -- making a personal response likely. MAKE IT BRIEF: True, your letter may not get read immediately by your representative. Put yourself in the shoes of the aid who opens the mailbag every day. There lie 1,000 identical protest postcards generated by some interest group. The aide counts them, yawns, and puts them aside. Then there are the new computerized form letters that have become the rage among grass-roots lobbying groups. The staffer can spot one in a second. They get put in the pile destined for poetic justice -- a response from the office computer, which can spew out a tailored letter in seconds. And then there's the 50th letter this week from the guy who writes in red crayon, decrying the lawmaker as a communist. You can guess where that goes. Finally, there's your letter, on real stationary, preferably with your business letterhead. Handwritten is best, most experts now suggest. "Writing on personal stationary distinguishes you from the mass mail," says Ira Chaleff of the nonprofit Congressional Management Foundation. And the aide is more likely to give it special attention. Keep to one subject, and keep it short. If you throw in all your peeves and concerns, it's likely to go to three of four different aides, each handling a different area. It's also a good idea to remind the representative or senator of a time you might have met. If you get a form letter back from the congressional office, don't just accept it, says George Gould of the National Association of Letter Writers. Write another one saying, "You sent me a form letter, and you haven't answered my question, or addressed my concern." Chances are, you'll get a personal response next time around. --Douglas Harbrecht Paul S. R. Chisholm, AT&T Bell Laboratories att!pegasus!psrc, psrc@pegasus.att.com, AT&T Mail !psrchisholm I'm not speaking for the company, I'm just speaking my mind. ------------------------------ Date: Fri, 6 Oct 89 11:13:57 PDT From: Peter Scott Subject: Re: What to do with the $30 billion (missions): A Plan gem.mps.ohio-state.edu!uwm.edu!mailrus!jarvis.csri.toronto.edu!utgpu!utzoo!henry@tut.cis.ohio-state.edu (Henry Spencer) writes: >In the absence of a *plan* (see previous oration), the >missions get chosen on PR value rather than rational scientific priority. Ah, but there *is* a plan... have you seen the Integrated Space Plan from Rockwell? I must admit, the first time I saw it, I thought it was a practical joke. After all, it's a single piece of paper about 3' by 5' covered with text and boxes and lines at about the density of VLSI blueprints, covering the entire range of manned/unmanned activity in space from now past the year 2100. However, it does make for some fascinating reading. [Someone here added a footnote to the poster at the bottom, between "Human Interstellar Travel" and "Interstellar Traversing Worldships", just below "Stationary Martian Skyhook", that said, "Man realizes all this rigamarole was not worth the bother and goes back into caves".] There is a note saying that comments are welcome and copies can be ordered from Rockwell International, Space Transportation Systems Division, 12214 Lakewood Boulevard, Downey, CA 90241, Attn: Ed Repic, Project Manager, Lunar & Planetary Systems, Mail Code AD21. Apologies to Rockwell if this results in many more people requesting said poster than they bargained upon; there is no restriction mentioned on the plan. So now there's no need for any more argument about what to do :-) Peter Scott (pjs@grouch.jpl.nasa.gov) ------------------------------ Date: 6 Oct 89 19:38:24 GMT From: agate!sandstorm.Berkeley.EDU!gwh@ucbvax.Berkeley.EDU (George William Herbert) Subject: Re: The 'Face' of Mars In article <301@runxtsa.runx.oz.au> clubmac@runxtsa.runx.oz.au (Macintosh Users Group) writes: >Does anyone know about the 'face' on Mars? Apparently, a computer-enhanced >image of a place on Mars revealed a humanoid face under layers of red dust. SHort version of the LONG story: There was a science writer who thought there was a face like object on Mars, By the name of Hoagland. He wrote a book, detailing all his views, copnnecting a bunch of interesting surface phenomena. NASA did enhancements and determined this to be mistaken, and sat on the negative data for a while, leading any number of people to fall for the story... It has been debunked. -george william herbert ------------------------------ Date: 6 Oct 89 14:43:23 GMT From: dftsrv!cdc910b21!schom@ames.arc.nasa.gov (Mark R. Schoeberl) Subject: Re: NASA Headline News for 09/29/89 (Forwarded) In article <549@castle.ed.ac.uk> bob@castle.ed.ac.uk (Bob Gray) writes: >In article <32735@ames.arc.nasa.gov> yee@trident.arc.nasa.gov (Peter E. Yee) quotes: >>This is NASA Headline News for Friday, September 29.... > >>"greenhouse" warming. And a NASA atmospheric scientist predicts >>that the ozone hole over antarctica will get even larger this >>fall due to the increase of chloroflourocarbons in the >>atmosphere. > >And James Lovelock, of the "Gaia Hypothesis" fame, is >predicting that the ozone hole will be smaller again this >year than last year. This was after after reaching its >maximum size back in 1987. > >He blames the volcanic eruption back in 1982 in south >America for dumping millions of tons of chemicals into the >atmosphere. These chemicals he believes are now dispersing. > The ozone hole over Antarctica this year is as big as 1987. Virtually all the ozone in the region from 12 to 25 km disappeared in 1987 and the same appears to be holding true for this year. The vertical extent of the depletion region determines the maximum depth the hole can achieve, and is determined by polar meteorology. The size of the hole is determined by the size of the polar vortex which is set up before the hole forms. There is little chance that the polar vortex will increase in size dramatically from 1987 or 1989 over the next few years. Those years (1987 and 1989) represent the most favorable conditions we have seen for vortex formation. So much for James Lovelock.... - Mark Schoeberl NASA/Goddard Space Flight Center ------------------------------ Date: 6 Oct 89 15:08:40 GMT From: skipper!shafer@ames.arc.nasa.gov (Mary Shafer) Subject: Re: X-30, Space Station Strangles NASP In article <6430@quick.COM> srg@quick.COM (Spencer Garrett) writes: In article , shafer@elxsi.dfrf.nasa.gov (Mary Shafer) writes: -> -> The shuttle comes in from the north to north east. It comes "feet -> dry" at about Mach 7 and 145K ft, it's overhead at Edwards at Mach 1 -> at about 40K ft. It does a HAC (Heading Alignment Circle) to put it -> on the runway heading (usually 17 or 22), so essentially the pattern -> is about a 270 teardrop with a longish final. I think it's a 20 deg -> glidepath, with a fairly short flair. Final is flown at 285 KEAS, -> gear deployed at 275 KEAS, touchdown at 185 KEAS. (I'm taking these -> figures from Young and Crippen's 1981 SETP paper on STS-1, so the -> speeds may not be exact for any given mission, but they're about -> right.) Um, I believe that should be *towards* N-NE. I meant from West to North-West. The orbits aren't equatorial. (I think the angle of inclination can be over 40 deg, but I don't have one of the ground-track maps to confirm this.) They usually land on 17 or 22, although they have landed on 15. The Shuttle uses *two* glidepaths on final. They fly most of the approach on a 17 degree (as I recall) glideslope, then make an abrupt pitch up to the normal 3 degree glideslope. It looks like the two intersect right off the end of the runway (where "right off" may be a mile or two at these speeds) and they only spend a few seconds (10 or 15?) on the 3 degree slope before starting the flare. They come around the HAC (heading alignment circle) and aim at a point on the lakebed about 1 mi before the touchdown point. This point is identified by a big X in black paint and a set of directional lights. (Actually they're narrowish spotlights.) This first portion, known appropriately as "final", is about a 20 deg glide slope. When they get fairly close to the ground they "flare" to a 3 deg glide slope, using the ball and bar beside the runway. Now for the questions! Is "coming feet dry" the same as extending the landing gear? I'm pretty sure I remember seeing the gear pop out *after* the flare, and I can't imagine having to design gear (much less gear doors) that could handle Mach 7! Coming "feet dry" means coming over dry land at the coastline. (I've been talking with too many Navy attack pilots. Sorry.) You're right about the gear; they pop it at about 150 ft AGL, maybe lower. It _always_ looks like they've left it until too late. And what's the "E" in KEAS? Surely Edwards doesn't have its own standard of measurement! :-} Equivalent. Ve = Vt * sqrt(rho/rhosl), where Ve is equivalent velocity, Vt true velocity, rho density at altitude, rhosl sea level density. (I need subscripts!) At sea level, Ve = Vt. In fact, at Edwards Ve pretty much equals Vt. However, at 40 K ft .... My Flight Test Engineer's Handbook says that Ve is frequently used for piston-engined aircraft (because it's a direct function of dynamic pressure, or qbar). We don't use it commonly here at Dryden, but we do use qbar itself. Since qbar is a primary measurement it's more sensible to use it, rather than Ve, which is a derived term. We mostly fly fighters and other military aircraft so we use KIAS or KCAS for airspeed. Is anybody interested in how and why we instrument our research aircraft? If so, I'll write something. -- Mary Shafer shafer@elxsi.dfrf.nasa.gov ames!elxsi.dfrf.nasa.gov!shafer NASA Ames-Dryden Flight Research Facility, Edwards, CA Of course I don't speak for NASA ------------------------------ End of SPACE Digest V10 #128 *******************