Date: Wed, 5 May 93 06:22:13 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V16 #525 To: Space Digest Readers Precedence: bulk Space Digest Wed, 5 May 93 Volume 16 : Issue 525 Today's Topics: A Little Pace o' My Heart Now (was Re: Long term Human Missions) Boeing TSTO (Was: Words from Chairman of Boeing) (2 msgs) Drag-free satellites (2 msgs) Electrical Spacecraft via Magnetic field of earth? HST Servicing Mission Scheduled for 11 Days large accelerations revisited Single Launch Space Station Space FAQ 14/15 - How to Become an Astronaut Space Manuevering Tug (was HST servicing mission_) Vandalizing the sky. Will NASA's Mars Observer Image the Face on Mars? Welcome to the Space Digest!! Please send your messages to "space@isu.isunet.edu", and (un)subscription requests of the form "Subscribe Space " to one of these addresses: listserv@uga (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle (THENET), or space-REQUEST@isu.isunet.edu (Internet). ---------------------------------------------------------------------- Date: 3 May 93 13:28:04 -0600 From: Bill Higgins-- Beam Jockey Subject: A Little Pace o' My Heart Now (was Re: Long term Human Missions) Newsgroups: sci.space,sci.space.shuttle In article <1993May3.095201.9800@ke4zv.uucp>, gary@ke4zv.uucp (Gary Coffman) writes: > In article <1993Apr28.133101.25145@rpslmc.edu> rek@siss81 (Robert Kaye) writes: >>3. Pacemakers (Kept my grandfather alive from 1976 until 1988) > > Pacemakers have been around since the 1940s. *Implantable* pacemakers > required development of solid state devices and externally rechargable > power sources. I worked for Cordis, a major manufacturer of cardiac pacemakers, in the summer of '75. I don't believe they made an "externally rechargeable" pacer at that time and I wonder whether such things existed. They ran on batteries (sorry, don't remember what kind). Batteries and electronics were potted in epoxy in an assembly about the size of a plum. A surgeon attached leads to the right part of the heart, and the leads ran to a pacer implanted in the patient's abdomen. Every two or three years, when the battery life was ended, they would do an operation to snip the leads, remove the pacer, and splice a fresh one into the old lead. This was simpler than doing more heart surgery. The technology was old since they had to prove extreme reliability; when I was there the first models containg integrated circuits were just entering service. These were clever: they had a magnetic read switch inside. A physician could put a big coil against a patient's chest and reprogram the pacer for different heart rate, etc. with a series of pulses. Cordis had done a lot of development on the nuclear-powered pacer, basically plutonium RTG like the one that runs Voyager or Galileo. It had a 20-year rated lifetime, but was kind of a mismatch since most pacer patients don't live 20 years after their operation. They were "installed" in a few people but there were big safety concerns (what if the plutonium gets loose in some horrible car wreck?). The labs were working on a 10-year model based on new lithium batteries that threatened to make the nuclear pacemaker obsolete. I guess they did. O~~* /_) ' / / /_/ ' , , ' ,_ _ \|/ - ~ -~~~~~~~~~~~/_) / / / / / / (_) (_) / / / _\~~~~~~~~~~~zap! / \ (_) (_) / | \ | | Bill Higgins Fermi National Accelerator Laboratory \ / Bitnet: HIGGINS@FNAL.BITNET - - Internet: HIGGINS@FNAL.FNAL.GOV ~ SPAN/Hepnet: 43011::HIGGINS ------------------------------ Date: Mon, 3 May 1993 18:20:53 GMT From: Henry Spencer Subject: Boeing TSTO (Was: Words from Chairman of Boeing) Newsgroups: sci.space In article schumach@convex.com (Richard A. Schumacher) writes: >[Description of Boeing study of two-staged spaceplane using >supersonic ramjets deleted.] > >In other words, Boeing is not seriously thinking about >reliable, less-expensive access to orbit. They just like >to fool around with exotic airplanes. More precisely, they see themselves as basically being in the airplane business, and prefer launcher designs that exploit, and add to, their airplane experience. This is probably not the best way to get to orbit, but it may well be the optimum way for *Boeing* to try to get to orbit, since they (rightly) think that even if they do get into the space business, airplanes will be their main business for many years yet. Note, though, that even if it's not the *best* way to get to orbit, it may well be a workable way of getting reliable, less-expensive access to orbit... if done right. One thing that came out pretty clearly at Making Orbit '93 is that *there are lots of ways to do cheap launchers*. It is quite reasonable to let external factors, e.g. the nature of Boeing's current business, dictate basic configuration, because you don't *need* to pick the very best configuration. Getting into orbit simply is not that hard. The right configuration will not automatically give you high reliability and low costs; configuration is a secondary issue. Personally, I agree that Boeing's configuration is less than ideal, if your sole objective is orbit. Getting involved with aerodynamics in a serious way when you don't have to (and launchers don't have to) is silly and counterproductive. But if you are *already* in the aerodynamics business, and plan to stay in it, that changes things a bit. -- SVR4 resembles a high-speed collision | Henry Spencer @ U of Toronto Zoology between SVR3 and SunOS. - Dick Dunn | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 3 May 1993 14:08:50 -0400 From: Matthew DeLuca Subject: Boeing TSTO (Was: Words from Chairman of Boeing) Newsgroups: sci.space [Snipe and countersnipe about Boeing TSTO vehicle research deleted] One thing I think people need to be careful about is falling into the One True Faith mode of thinking where SSTO (as represented by Delta Clipper) is the One True Way to better and cheaper access to space. There are any number of possible ways into orbit from the ground, and if Boeing wants to look into some of these we should be cheering them on; perhaps their final concept won't be quite as fast and cheap as Delta Clipper hopes to be, but it may have other benefits (greater cargo capacity, greater on-orbit maneuverability, lower launch accelerations, et cetera et cetera) that make it worthwhile. Personally, I wish them the best of luck. Or, if you don't want to think of it in the above manner, think of it this way: Boeing is a private airplane company (now here's a radical concept, an aircraft company doing research into exotic aircraft) and if they want to look into this for access to space they are more than welcome to do so. Even if it turns out to be hideously expensive and highly unreliable, they're not on a mission from NASA, God, or anyone else to provide better access to orbit. So there. -- Matthew DeLuca Georgia Institute of Technology, Atlanta Georgia, 30332 uucp: ...!{decvax,hplabs,ncar,purdue,rutgers}!gatech!prism!matthew Internet: matthew@phantom.gatech.edu ------------------------------ Date: Mon, 3 May 1993 17:49:30 GMT From: Henry Spencer Subject: Drag-free satellites Newsgroups: sci.space In article <15821.2be3e125@cpva.saic.com> thomsonal@cpva.saic.com writes: >> No. A "dragless" satellite does not magically have no drag; it burns fuel >> constantly to fight drag, maintaining the exact orbit it would have *if* >> there was no drag. > > Well, almost. It turns out that clever orbital mechanics can >engineer things so that resonant interactions with the higher order >harmonics of the Earth's gravitational field can pump energy into a >satellite, and keep it from experiencing drag effects for periods of >months to years. These are two entirely different things, actually. The "dragless" satellites previously discussed were as I described them: using thrust to cancel the effects of air drag, measured relative to suspended masses shielded against it. Allen is talking about satellites that experience drag, and make no particular effort to compensate for it (that is, a sensitive accelerometer aboard one would detect a steady deceleration), but exploit tricks of orbital mechanics to minimize the *effects* of the drag on the overall orbit. -- SVR4 resembles a high-speed collision | Henry Spencer @ U of Toronto Zoology between SVR3 and SunOS. - Dick Dunn | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Mon, 3 May 1993 18:16:03 GMT From: Scott Stallcup Subject: Drag-free satellites Newsgroups: sci.space Isaac Kuo (isaackuo@skippy.berkeley.edu) wrote: : : In any case, the small difference from spherical that the Earth is is : ridiculously small. Even counting all of the mountains, etc. that make the : Earth bumpy, the Earth is closer to a sphere than the smoothest billiard : ball. : : Even if the Earth were significantly flattenned, it would be flattenned on : the axis of rotation, and thus the gravitational field does not rotate and : thus no orbiting satellite can derive energy from the non-changing : gravitational field. : -- I don't have the numbers handy, but I can assure you that Earth Oblateness is one of the major factors in orbit/attitude determination calculations. The three major factors are atmospheric drag, Earth oblateness, and solar pressure. Surface "bumps" (mountains) are not a major factor but the equatorial bulge is an important factor. ---------------------------------- Scott Stallcup Space Telescope Science Institute ------------------------------ Date: Mon, 3 May 1993 17:45:23 GMT From: Henry Spencer Subject: Electrical Spacecraft via Magnetic field of earth? Newsgroups: sci.space In article <1s16e4$83v@access.digex.net> prb@access.digex.net (Pat) writes: >>... A "dragless" satellite does not magically have no drag; it burns fuel >>constantly to fight drag, maintaining the exact orbit it would have *if* >>there was no drag... > >What is the point of it? are they used for laser geodesy missions? >triad seemed to be some sort of navy navigation bird, but why >be "dragless" why not just update orbital parameters? The main point of it, for the missions to date, has been very accurate measurement of gravitational phenomena, where air drag is an unwanted complication. You can cancel it out much more accurately than you can measure it (in fact, the most accurate way to measure it is to measure how hard a cancellation system is working). It might perhaps have future applications to really serious microgravity research, emphasis on the "micro". -- SVR4 resembles a high-speed collision | Henry Spencer @ U of Toronto Zoology between SVR3 and SunOS. - Dick Dunn | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Mon, 3 May 1993 18:03:51 GMT From: Henry Spencer Subject: HST Servicing Mission Scheduled for 11 Days Newsgroups: sci.space,sci.space.shuttle,sci.astro In article <1993May3.123559.26322@slcs.slb.com> brydon@dsn.SINet.slb.com writes: >>[HST] needs occasional reboosting or it will eventually reenter. (It has >>no propulsion system of its own.)... > >If it has no propulsion system, how does it maneuver itself? It can *point* in any direction using momentum wheels (reaction wheels whose nominal "zero state" is a substantial spin rate) (terminology as in Wertz, "Spacecraft Attitude Determination and Control" -- the usage of the various terms is not consistent across the field, so please let us have no quibbles over what the words mean). To turn in one direction, spin an internal wheel in the opposite direction, and the torque on the wheel will turn the spacecraft. Asymmetric external torques eventually have the wheels spinning faster and faster to compensate, so you need some way of dumping momentum, which HST does with electromagnets that exert a torque against Earth's magnetic field. But it has no propulsion system -- no way of changing its orbit. -- SVR4 resembles a high-speed collision | Henry Spencer @ U of Toronto Zoology between SVR3 and SunOS. - Dick Dunn | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Mon, 3 May 1993 17:38:29 GMT From: Henry Spencer Subject: large accelerations revisited Newsgroups: sci.space In article wohlmuth@cehpx10 (Walter Wohlmuth) writes: >Why can't an aircraft be designed so that the pilot can always be >maintained in a upright position, perpendicular to the plane of >acceleration? ... Actually, for high accelerations you want the pilot perpendicular to the acceleration vector. (This may be what Walter meant.) It's not impossible -- there has been work with things like auto-reclining seats that might be considered a first approximation -- but it creates problems, notably restricting the pilot's view. (The nifty display technologies that Walter mentions are nowhere near equalling the human eye for practical combat flying.) -- SVR4 resembles a high-speed collision | Henry Spencer @ U of Toronto Zoology between SVR3 and SunOS. - Dick Dunn | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Mon, 3 May 1993 17:26:41 GMT From: Andrew Curtis Subject: Single Launch Space Station Newsgroups: sci.space In article 0004244402@mcimail.com (Karl Dishaw) writes: >Andy Cohen writes: >>the Single Launch Core Station concept. A Shuttle external tank and solid >>rocket boosters would be used to launch the station into orbit. Shuttle >>main engines would be mounted to the tail of the station module for launch >>and jettisoned after ET separation. > >Why jettison the SSMEs? Why not hold on to them and have a shuttle >bring them down to use as spares? > > >Karl >sold my soul to Uncle Sam . . . now marked down for resale. > It's not the same as throwing a spare tire in your trunk ;-) It's undoubtedly cheaper to dispose of a set of SSMEs which are nearing the end of their operational life cycle (they are all refurbished and re-used already) than to design, build, test, certify, and fly the single use hardware necessary to secure the SSMEs in the cargo bay. That doesn't even include the cost of the EVAs or other crew operations necessary to transfer the SSMEs from the station to the shuttle cargo bay. ------------------------------ Date: 3 May 1993 12:23:56 -0400 From: Jon Leech Subject: Space FAQ 14/15 - How to Become an Astronaut Newsgroups: sci.space,sci.answers,news.answers Archive-name: space/astronaut Last-modified: $Date: 93/05/03 12:07:55 $ HOW TO BECOME AN ASTRONAUT First the short form, authored by Henry Spencer, then an official NASA announcement. Q. How do I become an astronaut? A. We will assume you mean a NASA astronaut, since it's probably impossible for a non-Russian to get into the cosmonaut corps (paying passengers are not professional cosmonauts), and the other nations have so few astronauts (and fly even fewer) that you're better off hoping to win a lottery. Becoming a shuttle pilot requires lots of fast-jet experience, which means a military flying career; forget that unless you want to do it anyway. So you want to become a shuttle "mission specialist". If you aren't a US citizen, become one; that is a must. After that, the crucial thing to remember is that the demand for such jobs vastly exceeds the supply. NASA's problem is not finding qualified people, but thinning the lineup down to manageable length. It is not enough to be qualified; you must avoid being *dis*qualified for any reason, many of them in principle quite irrelevant to the job. Get a Ph.D. Specialize in something that involves getting your hands dirty with equipment, not just paper and pencil. Forget computer programming entirely; it will be done from the ground for the fore- seeable future. Degree(s) in one field plus work experience in another seems to be a frequent winner. Be in good physical condition, with good eyesight. (DO NOT get a radial keratomy or similar hack to improve your vision; nobody knows what sudden pressure changes would do to RKed eyes, and long-term effects are poorly understood. For that matter, avoid any other significant medical unknowns.) If you can pass a jet-pilot physical, you should be okay; if you can't, your chances are poor. Practise public speaking, and be conservative and conformist in appearance and actions; you've got a tough selling job ahead, trying to convince a cautious, conservative selection committee that you are better than hundreds of other applicants. (And, also, that you will be a credit to NASA after you are hired: public relations is a significant part of the job, and NASA's image is very prim and proper.) The image you want is squeaky-clean workaholic yuppie. Remember also that you will need a security clearance at some point, and Security considers everybody guilty until proven innocent. Keep your nose clean. Get a pilot's license and make flying your number one hobby; experienced pilots are known to be favored even for non-pilot jobs. Work for NASA; of 45 astronauts selected between 1984 and 1988, 43 were military or NASA employees, and the remaining two were a NASA consultant and Mae Jemison (the first black female astronaut). If you apply from outside NASA and miss, but they offer you a job at NASA, ***TAKE IT***; sometimes in the past this has meant "you do look interesting but we want to know you a bit better first". Think space: they want highly motivated people, so lose no chance to demonstrate motivation. Keep trying. Many astronauts didn't make it the first time. NASA National Aeronautics and Space Administration Lyndon B. Johnson Space Center Houston, Texas Announcement for Mission Specialist and Pilot Astronaut Candidates ================================================================== Astronaut Candidate Program --------------------------- The National Aeronautics and Space Administration (NASA) has a need for Pilot Astronaut Candidates and Mission Specialist Astronaut Candidates to support the Space Shuttle Program. NASA is now accepting on a continuous basis and plans to select astronaut candidates as needed. Persons from both the civilian sector and the military services will be considered. All positions are located at the Lyndon B. Johnson Space Center in Houston, Texas, and will involved a 1-year training and evaluation program. Space Shuttle Program Description --------------------------------- The numerous successful flights of the Space Shuttle have demonstrated that operation and experimental investigations in space are becoming routine. The Space Shuttle Orbiter is launched into, and maneuvers in the Earth orbit performing missions lastling up to 30 days. It then returns to earth and is ready for another flight with payloads and flight crew. The Orbiter performs a variety of orbital missions including deployment and retrieval of satellites, service of existing satellites, operation of specialized laboratories (astronomy, earth sciences, materials processing, manufacturing), and other operations. These missions will eventually include the development and servicing of a permanent space station. The Orbiter also provides a staging capability for using higher orbits than can be achieved by the Orbiter itself. Users of the Space Shuttle's capabilities are both domestic and foreign and include government agencies and private industries. The crew normally consists of five people - the commander, the pilot, and three mission specialists. On occasion additional crew members are assigned. The commander, pilot, and mission specialists are NASA astronauts. Pilot Astronaut Pilot astronauts server as both Space Shuttle commanders and pilots. During flight the commander has onboard responsibility for the vehicle, crew, mission success and safety in flight. The pilot assists the commander in controlling and operating the vehicle. In addition, the pilot may assist in the deployment and retrieval of satellites utilizing the remote manipulator system, in extra-vehicular activities, and other payload operations. Mission Specialist Astronaut Mission specialist astronauts, working with the commander and pilot, have overall responsibility for the coordination of Shuttle operations in the areas of crew activity planning, consumables usage, and experiment and payload operations. Mission specialists are required to have a detailed knowledge of Shuttle systems, as well as detailed knowledge of the operational characteristics, mission requirements and objectives, and supporting systems and equipment for each of the experiments to be conducted on their assigned missions. Mission specialists will perform extra-vehicular activities, payload handling using the remote manipulator system, and perform or assist in specific experimental operations. Astronaut Candidate Program =========================== Basic Qualification Requirements -------------------------------- Applicants MUST meet the following minimum requirements prior to submitting an application. Mission Specialist Astronaut Candidate: 1. Bachelor's degree from an accredited institution in engineering, biological science, physical science or mathematics. Degree must be followed by at least three years of related progressively responsible, professional experience. An advanced degree is desirable and may be substituted for part or all of the experience requirement (master's degree = 1 year, doctoral degree = 3 years). Quality of academic preparation is important. 2. Ability to pass a NASA class II space physical, which is similar to a civilian or military class II flight physical and includes the following specific standards: Distant visual acuity: 20/150 or better uncorrected, correctable to 20/20, each eye. Blood pressure: 140/90 measured in sitting position. 3. Height between 58.5 and 76 inches. Pilot Astronaut Candidate: 1. Bachelor's degree from an accredited institution in engineering, biological science, physical science or mathematics. Degree must be followed by at least three years of related progressively responsible, professional experience. An advanced degree is desirable. Quality of academic preparation is important. 2. At least 1000 hours pilot-in-command time in jet aircraft. Flight test experience highly desirable. 3. Ability to pass a NASA Class I space physical which is similar to a military or civilian Class I flight physical and includes the following specific standards: Distant visual acuity: 20/50 or better uncorrected correctable to 20/20, each eye. Blood pressure: 140/90 measured in sitting position. 4. Height between 64 and 76 inches. Citizenship Requirements Applications for the Astronaut Candidate Program must be citizens of the United States. Note on Academic Requirements Applicants for the Astronaut Candidate Program must meet the basic education requirements for NASA engineering and scientific positions -- specifically: successful completion of standard professional curriculum in an accredited college or university leading to at least a bachelor's degree with major study in an appropriate field of engineering, biological science, physical science, or mathematics. The following degree fields, while related to engineering and the sciences, are not considered qualifying: - Degrees in technology (Engineering Technology, Aviation Technology, Medical Technology, etc.) - Degrees in Psychology (except for Clinical Psychology, Physiological Psychology, or Experimental Psychology which are qualifying). - Degrees in Nursing. - Degrees in social sciences (Geography, Anthropology, Archaeology, etc.) - Degrees in Aviation, Aviation Management or similar fields. Application Procedures ---------------------- Civilian The application package may be obtained by writing to: NASA Johnson Space Center Astronaut Selection Office ATTN: AHX Houston, TX 77058 Civilian applications will be accepted on a continuous basis. When NASA decides to select additional astronaut candidates, consideration will be given only to those applications on hand on the date of decision is made. Applications received after that date will be retained and considered for the next selection. Applicants will be notified annually of the opportunity to update their applications and to indicate continued interest in being considered for the program. Those applicants who do not update their applications annually will be dropped from consideration, and their applications will not be retained. After the preliminary screening of applications, additional information may be requested for some applicants, and person listed on the application as supervisors and references may be contacted. Active Duty Military Active duty military personnel must submit applications to their respective military service and not directly to NASA. Application procedures will be disseminated by each service. Selection --------- Personal interviews and thorough medical evaluations will be required for both civilian and military applicants under final consideration. Once final selections have been made, all applicants who were considered will be notified of the outcome of the process. Selection rosters established through this process may be used for the selection of additional candidates during a one year period following their establishment. General Program Requirements Selected applicants will be designated Astronaut Candidates and will be assigned to the Astronaut Office at the Johnson Space Center, Houston, Texas. The astronaut candidates will undergo a 1 year training and evaluation period during which time they will be assigned technical or scientific responsibilities allowing them to contribute substantially to ongoing programs. They will also participate in the basic astronaut training program which is designed to develop the knowledge and skills required for formal mission training upon selection for a flight. Pilot astronaut candidates will maintain proficiency in NASA aircraft during their candidate period. Applicants should be aware that selection as an astronaut candidate does not insure selection as an astronaut. Final selection as an astronaut will depend on satisfactory completion of the 1 year training and evaluation period. Civilian candidates who successfully complete the training and evaluation and are selected as astronauts will become permanent Federal employees and will be expected to remain with NASA for a period of at least five years. Civilian candidates who are not selected as astronauts may be placed in other positions within NASA depending upon Agency requirements and manpower constraints at that time. Successful military candidates will be detailed to NASA for a specified tour of duty. NASA has an affirmative action program goal of having qualified minorities and women among those qualified as astronaut candidates. Therefore, qualified minorities and women are encouraged to apply. Pay and Benefits ---------------- Civilians Salaries for civilian astronaut candidates are based on the Federal Governments General Schedule pay scales for grades GS-11 through GS-14, and are set in accordance with each individuals academic achievements and experience. Other benefits include vacation and sick leave, a retirement plan, and participation in group health and life insurance plans. Military Selected military personnel will be detailed to the Johnson Space Center but will remain in an active duty status for pay, benefits, leave, and other similar military matters. NEXT: FAQ #15/15 - Orbital and Planetary Launch Services ------------------------------ Date: Mon, 3 May 1993 17:27:58 GMT From: fred j mccall 575-3539 Subject: Space Manuevering Tug (was HST servicing mission_) Newsgroups: sci.space In <1s15p6$7lj@access.digex.net> prb@access.digex.net (Pat) writes: >In article jbh55289@uxa.cso.uiuc.edu (Josh Hopkins) writes: >>Second, remember why they had to improvise during Intelsat 6? They were trying >>to attach a motor to a piece of hardware that wasn't designed to do that. >>Trying to shortcut the training is only going to make a repeat more likely. >> >Also because they significantly lacked on-orbit EVA experience. >The HST is designed for on-orbit servicing. it should be a lot easier. There is a difference between 'on orbit servicing' and taping a motor to its butt and firing it, Pat. Keep in mind that this motor is going to have to thrust exactly through the center of mass of the HST or you're going to tumble. It is then going to have to cease firing cleanly, unbolt itself from HST, and move away (all without leaving any contamination). Note that most of this is not a problem when using the Shuttle for reboost, because it can basically wrap itself around the HST and all that stuff with center of mass is already computed. Plus, there are people on scene if anything goes wrong. >> >>"All they have to do is soup it up?" Just what does that mean? >> >I suspect, the BUS-1, may not have enough basic thrust for the HST >re-boost. it mayu need bigger tanks, or bigger thrusters. I see. So we change a bunch of stuff on it, then take it up and duct tape it to a $1G instrument and hope everything comes out ok? I think not. >> >>Pat, not only is this messy and less reliable than a device that's _made_ to >>perform this task, it also ignores the point. There is a desire to have >>astronauts available so that if the door fails to open, something can be done >>about it. Unless you can provide a very reliable way of reopening the door, >>you haven't solved the problem. >That door has cycled, X times already. Once after massive G loading. >I somehow think they can work ou;reliability methods to ensure the >door works. >Also, please tell me how some sort of sublimated material like >CO2, or H2O would manage to contaminate the mirror, anything >that goes to vapor state, shouldn't adhere to the mirror. Sounds like you're thinking of things in atmosphere, Pat. Any stray molecule in space may adhere to any solid surface it hits, whether it's 'vapor' or not. That's why there's a worry about contamination of the instruments by thruster exhaust, which is something of a vapor, last time I checked. -- "Insisting on perfect safety is for people who don't have the balls to live in the real world." -- Mary Shafer, NASA Ames Dryden ------------------------------------------------------------------------------ Fred.McCall@dseg.ti.com - I don't speak for others and they don't speak for me. ------------------------------ Date: Mon, 3 May 1993 17:58:07 GMT From: kevin patrick kretsch Subject: Vandalizing the sky. Newsgroups: sci.astro,sci.space Batman is one thing but K-Mart is another! Light pollution is bad enough but imagine a three mile long Coca-Cola sign!! And no, even if it is overcast, it doesn't make it O.K. I'm sick of the commercials on T.V., I don't want to see them when I go for a walk!! The sky was never intended to be a billboard (if it was intended at all!) and hopefully it never shall be. Imagine some artist painting a landscape... ...trees, mountains, river, sunsetting behind the giant Coca-Cola can... Great picture, huh ?? Kev. -- kkretsch@unix1.tcd.ie Dept. of pure and applied physics Undergrad Trinity College Dublin, Ireland Heaven is a big guitar shop that never charges... ------------------------------ Date: Mon, 3 May 1993 17:51:33 GMT From: Henry Spencer Subject: Will NASA's Mars Observer Image the Face on Mars? Newsgroups: sci.space In article gene@jackatak.raider.net (Gene Wright) writes: >All consipiracy theories aside, (they are watching though :-)), will NASA >try to image the Cydonia region of Mars where the "Face" is? They plan to try. It's not particularly high priority. Nobody in the planetary-science community believes the "face" is anything but a natural rock formation that happens to resemble a face when lit from the right angle. (Such formations exist on Earth too.) -- SVR4 resembles a high-speed collision | Henry Spencer @ U of Toronto Zoology between SVR3 and SunOS. - Dick Dunn | henry@zoo.toronto.edu utzoo!henry ------------------------------ End of Space Digest Volume 16 : Issue 525 ------------------------------