Date: Thu, 28 Jan 93 05:04:26 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V16 #084 To: Space Digest Readers Precedence: bulk Space Digest Thu, 28 Jan 93 Volume 16 : Issue 084 Today's Topics: Biosphere 2 Oxygen and other Questions Clinton's Promises (space) in Charlotte Observer (2 msgs) Elementary Ballistics Fluidic envelope on a point gravitational source suspended in a uniform field Galileo update? (3 msgs) JIAFS Lubrication problem (was Re: Galileo Stuck Ribs / Remote Manipulator?) Nasa Press Kit Nasa Select contact req ? Orbital Mechanics--Careers? Precursors to Fred (was Re: Sabatier Reactors.) (3 msgs) Saving an overweight SSTO.... TPS Systems Using off-the-shelf-components 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: Wed, 27 Jan 93 22:50:00 PST From: Taber@bio2.com Subject: Biosphere 2 Oxygen and other Questions Biosphere 2 Oxygen and other Questions January 27, 1993 Sixteen months down and eight to go. Sorry to be so long in posting answers to the many questions, I simply have not been able to make enough time in here. We don't know where all the oxygen has gone. This is one of the biggest mysteries so far. While the CO2 removal system can account for some of the O2 loss, as oxidation of organic material producing CO2, which was then removed from the air by the system. The amount of CO2 removed from the air only accounts for about one fifth of the total oxygen deficit. We have essentially two leading theories, first is oxidation of reduced compounds that may have been present at closure, like possibly a reduced iron. The second is oxidation of organic material in the soil and subsequent precipitation of the CO2 as a calcium carbonate, the parent materials for this are abundant but the necessary conditions are in question. We are also in the process of doing small chamber experiments with soil similar to that in Biosphere 2. Carbon and Oxygen isotopes are also being extensively studied for clews to what is going on. The soils are the main point of interest because it is the only place in the biosphere big enough to hide 12,000 Kg of O2. The CO2 is now at an average concentration of 3500 ppm, with a 400 to 500 ppm diurnal swing. The sunny weather we are having now is bringing the average CO2 concentration down at a rate of 80 ppm per diurnal cycle, without any use of the CO2 removal system which is now off. This means that the draw down during the day is 80 ppm greater than the rise at night. To put 3,500 ppm in perspective, a room with people in it and normal ventilation can easily get this high. Also CO2 concentrations between 5,000 and 8,000 ppm CO2 is not uncommon in the space shuttle and submarines. Human health difficulties seem to begin at about 9,000 to 11,000 ppm. Increased CO2 does result in faster growth rates with many plants. There was no bias against the Sabatier or Bosch systems, they were simply not considered necessary at the time. We had no idea that the oxygen phenomena would occur. What we did know was that during the winter we would have an excess of CO2 and in the summer quite possibly a deficit. We are able to put the CO2 back in the air during the summer and have it made into plant material, thus completing an annual cycle of CO2 storage and release. The summer release of CO2 should stimulate plant growth and replenish some of the oxygen. A basic problem with the Sabatier or Bosch systems and our situation is that we do not have enough CO2 in the air to significantly change the O2 using a system that would liberate the O2 form the CO2. Even in the summer with low CO2 in the air, the O2 loss is at about 0.26% O2 per month, while the average CO2 concentration is fairly constant at only 0.12%. Even converting all the CO2 in the air to C + O2 would have little effect on the O2 situation. Using such a system to drive the CO2 even lower would begin to reduce food crop production rates, because the plants would become limited by the availability of CO2. So there is no need to transform the CO2, just temporarily store it in the winter. Note that if we had constant high levels of light, like in space for instance, this CO2 storage scenario would be mute because we would have no need to try and survive a low light season! The CO2 removal system I designed uses sodium hydroxide as a scrubbing fluid, removing a fraction of all acid forming gasses in the air. This is done using a large reaction column with a high air flow rate, even so we can only remove 100 to 200 ppm per day with the system. On a low sunlight day the CO2 can jump up 300 to 400 ppm, so the system can only moderate trends. The sodium carbonates formed from the CO2 and sodium hydroxide are reacted with calcium hydroxide to form CaCO3 (limestone) which regenerates the scrubbing fluid back to sodium hydroxide. The CO2 is thus stored as CaCO3 until time to release the CO2, which is done by heating the CaCO3 making CaCO and CO2. The CaCO can then be re-hydrated with the water in the scrubbing fluid and all the chemicals are restored and ready for the next winter. This may not be the best system, but it works. It is too heavy for a space application but may possibly be made from local materials. Also a basic problem with any system is the need to process a large volume of air. If the CO2 was at 1000 ppm, then for every liter of CO2 removed, one needs to process 2000 liters of air with a 50% efficient system. This can be done either by pre-concentrating, which is difficult with a volume as big as Biosphere 2, or processing the whole air which is also hard. Ambient temperature scrubbing of air in a reaction column, using a hydroxide, can handle large volumes of air quite easily. A similar system is used in space craft with solid lithium hydroxide. Pressure swing systems are being considered for space station using materials that adsorb CO2 at cabin pressure and release the CO2 to space vacuum and/or with heating. The smell is usually great. I have a pure air generator that makes very clean air by pressure swing adsorption, air with no smell. By breathing this air for a period of about 30 minutes, it tends to "zero" my sense of smell so for a short time after, 4 to 10 minutes, I can smell the air in the Biosphere. It smells like rich farm soil (not potting mix), a sweet fresh smell. There are some exceptions to this, like when the sewage system has a problem such as inadvertent overflowing, but after cleanup the smell only persists for one to three of hours. Also if a container of some wet organic material is not tended, it can smell rather bad. Methane buildups have not occurred, this is probably due to methanotrophic bacteria increasing to consume the methane thereby keeping it in check. We have thus-far had no problem with any trace compounds building up in the atmosphere or water supply. We haven't even needed to use the soil bed reactor system to clean the air. The soil bed reactor is designed to force air through the soil in the agriculture biome as a means of cleaning the air. We are now at the two thirds mark, I am sorry to say that I can not be more specific than to say that group dynamics are quite exciting. Some studies I have seen say that in a situation with a confined crew, the third quarter is usually the most difficult time. Oxygen additions are continuing, we are now at about 17.5%. The low light conditions that we have had over the last two months may delay harvest times with some crops as much as a month. The effect of this on our total food production will not be fully seen until mid March, at which time we will be able to evaluate the situation decisively. Taber MacCallum Biosphere 2 Crew ------------------------------ Date: Wed, 27 Jan 1993 02:10:23 GMT From: "Bruce F. Webster" Subject: Clinton's Promises (space) in Charlotte Observer Newsgroups: sci.space In article <21JAN199320444611@judy.uh.edu> wingo%cspara.decnet@Fedex.Msfc.Nasa.Gov writes: > In article , ewright@convex.com (Edward V. Wright) writes... > >In rabjab@golem.ucsd.edu (rabjab) writes: > > > >>> B. Support completion of the space station Freedom. > > > >>Looks like Clinton is going to make some rather severe cuts in space > >>projects. And "supporting completion" doesn't mean actual completion. > > > >You don't understand. NASA doesn't *want* Space Station Freedom > >completed. > > > > No you don't understand and your statement is a prime reason people like > you are not listened to at NASA. Even looking at the proposition from a > pragmatical political perspective, this statment of yours is false. Why? > > If NASA drags their feet and does not finish the station costs soar and > nothing gets done. Space Station Freedom was originally proposed in what? 1982?, was supposed to be on orbit and operational in 1992, and was supposed to cost a total of $8B. It is now 1993, not a single actual piece of Fred has been built (much less placed on orbit), and the estimated total cost is $40B and rising. Q.E.D. I used to work for NASA (as an employee of Singer/Link, the former contractor on the Space Shuttle Flight Simulator at JSC) and also worked at the Lunar and Planetary Institute next door. I have friends who are still heavily involved in the space industry at various levels. I happen to think that the best thing Clinton could do would be to kill SS Fred and offer $10B, tax-free, to the first US corporation or consortium to put a station on orbit and keep it staffed by at least X people for a year and day. He should also offer $5B to the second corporation/consortium to do the same thing. The government would spend less, create more jobs, and built an 21st century industrial base. ..bruce.. ------------------------------------------------------------------------------- Bruce F. Webster | We hackers linger by our leading edge CTO, Pages Software Inc | Forgetting what is pending in the cache bwebster@pages.com | Till practice hurtles past us, and we crash. #import | -- Jeff Duntemann ------------------------------------------------------------------------------- ------------------------------ Date: 27 Jan 1993 15:58:06 GMT From: Doug Mohney Subject: Clinton's Promises (space) in Charlotte Observer Newsgroups: sci.space In article <1993Jan27.021023.8557@pages.com>, bwebster@pages.com (Bruce F. Webster) writes: >. I have friends who are still heavily involved in >the space industry at various levels. I happen to think that the best thing >Clinton could do would be to kill SS Fred and offer $10B, tax-free, to the >first US corporation or consortium to put a station on orbit and keep it >staffed by at least X people for a year and day. He should also offer $5B to >the second corporation/consortium to do the same thing. The government would >spend less, create more jobs, and built an 21st century industrial base. Gosh, you been hanging out with Jerry Pournelle, huh? He has expounded on the bonus plan to build a moon colony through the same fashion. I got some questions for you: A) Who owns possession of the technology used to develop the station? B) Who owns the data? C) How do you set the damned thing up without using goverment help in the first place? Guess who owns all the big launch facilities. (Unless, of course, you wish to disguise this as a Russian Marshall Plan, which is not necessary a Bad Thing. Just be say so up front). D) Does it have to be a U.S. corp? What if I use off-shore tech, say get the Italians into building my living modules? IF, in exchange for the prize money, the government gets rights to the "science" without infringing on trade secrets, it might work. I have talked to Ehud, and lived. -- > SYSMGR@CADLAB.ENG.UMD.EDU < -- ------------------------------ Date: Wed, 27 Jan 1993 07:49:20 GMT From: Henry Spencer Subject: Elementary Ballistics Newsgroups: sci.space,sci.physics,alt.pagan In article matt@wardsgi.med.yale.edu (Matt Healy) writes: >Several people pointed out that LEO takes about 8 km/sec, >minimum. This is in the FAQ. However, I haven't seen any >posts giving the simple math behind the 8 km/sec figure, >so I'll crack open Halliday & Resnick {Physics}: > >centripetal acceleration for a body following a circular >path... One standard "g" is 9.81 meter/second_squared... Do remember, though, that the acceleration of gravity varies somewhat with altitude. The correct formula for circular-orbit velocity is v = sqrt(GM/r), where G is the constant of gravitation, M is the mass of the Earth, and r is the radius of the orbit. (Actually, in practice, what you look up in a table is GM rather than G and M separately. The gravitational constant is a colossal pain to measure because gravity is so weak, and it is known to only about four digits. The GM of a planet will typically be known far more precisely than M, because GM can be determined directly from satellite orbits but getting M requires dividing GM by the poorly-known G.) The rule of thumb is that low orbit is at about 8 km/s, and you need maybe 9.3 km/s to get from the surface to low orbit despite gravity losses and air resistance. That does assume relatively low velocity during the climb through the thick low-altitude atmosphere, though, or you lose much more to drag. >But how would a *real* mass driver handle the problem of >getting up *above* the atmosphere and then circularizing >the orbit? ... First, some terminology: "mass driver" refers to a very specific type of electromagnetic catapult -- one with recirculating payload-carrying "buckets", a concept invented by Gerard O'Neill -- and is *NOT*, repeat *NOT*, a generic synonym for "gun" or "catapult". As for how gun/catapult systems handle circularization: there has to be some extra velocity change imparted by other means, e.g. an apogee kick motor or a tether system. Ignoring some fine points, an orbit always passes through the point of the last velocity change. If you want the low point of the orbit to be above the atmosphere, there has to be a velocity change done up there. -- "God willing... we shall return." | Henry Spencer @ U of Toronto Zoology -Gene Cernan, the Moon, Dec 1972 | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Wed, 27 Jan 1993 14:58:07 GMT From: James Meritt Subject: Fluidic envelope on a point gravitational source suspended in a uniform field Newsgroups: talk.origins,sci.space What would the characteristics be of the fluidic envelope (atmosphere and hydrosphere) of a gravitational point source (say, the earth) if it were to be suspended (through some magical method which would NOT affect the oceans) in a uniform (or near-uniform) intense (approximately 6 meters per second per second) gravitational field (say, from something that would become Saturn)? Off hand, I wonder about the long-term status of the atmosphere. Would the escape velocity on the "near" side be reduced such that the molecular velocity at "room temperature" be sufficient to "bleed off" the air? What WOULD the imposition of a uniform field over the inverse square field do the e.v.? Someone care to perform the integral? What would the physical distribution of the object be? On the planetary surface, the vector sum of the two fields would make "downhill" towards the primary (except in a line straight through the center of mass of the secondary (earth). On the "near" point, 'g' would be reduced and on the "far" point 'g' would be increased. The equipotential surface would be furthest from the center of mass of the secondary on the "far" side and nearest to the center of mass on the "near" side. How would this affect things? Would the lithosphere retain sphericality, or is the material strength insufficient to prevent drastic redistribution to conform with the equipotential shape (read: terminal earthquakes). What would the atmospheric pressure be, since the mass of the atmosphere would be on the "far" side and the 'g' is reduced on the 'near' side? Would the partial pressure of O2 be sufficient for respiration? Would there be ANY oceans & lakes on the "near" side? -- James W. Meritt: m23364@mwunix.mitre.org - or - jmeritt@mitre.org The opinions above are mine. If anyone else wants to share them, fine. They may say so if they wish. The facts "belong" to noone and simply are. ------------------------------ Date: Wed, 27 Jan 1993 13:39:08 GMT From: Jarno Kokko Subject: Galileo update? Newsgroups: sci.space In article <26JAN199316452669@kelvin.jpl.nasa.gov> baalke@kelvin.jpl.nasa.gov (Ron Baalke) writes: >In article <93025.205009IO20721@MAINE.MAINE.EDU>, Michael Petersen writes... >>Could someone tell me if NASA has successfully deployed the high-gain >>antenna on Galileo yet? I heard that their most "aggressive" attempts >>would occur after the the last Earth flyby. > >The recent hammerings have not opened the antenna. The first hammering >attempt turned the ballscrew an additional full rotation, but it has >not budged since. Despite 13,000+ hammerings at different frequencies >and at various antenna temperatures, the ribs are still stuck. One last >attempt will be made by spinning up the spacecraft from 3 rpm to 10 rpm >in March, but this is not expected to do much. March has been designated >as the deadline to open the antenna. After that the focus will be >on the Ida flyby in August and a low gain antenna mission. One other >event that may open the antenna is the Jupiter orbit insertion in December >1995. The solid rotor motor will fire for an hour and the resulting >vibrations may jar the antenna loose, but this is to be considered a long shot. > ___ _____ ___ > /_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov > | | | | __ \ /| | | | Jet Propulsion Lab | > ___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Every once in a while, >/___| | | | ___/ | |/__ /| Pasadena, CA 91109 | try pushing your luck. >|_____|/ |_|/ |_____|/ | > Have people thought about combining hammering with the orbit insertion? I think hammering when whole spacecraft is vibrating due to motor firing would shake loose about anything :-) .. Or is it impossible due to some minor technical detail? - Jarnis ------------------------------ Date: 27 Jan 1993 16:25 UT From: Ron Baalke Subject: Galileo update? Newsgroups: sci.space In article <1993Jan27.133908.16401@prime.mdata.fi>, jarnis@mits.mdata.fi (Jarno Kokko) writes... >Have people thought about combining hammering with the orbit insertion? >I think hammering when whole spacecraft is vibrating due to motor >firing would shake loose about anything :-) .. Or is it impossible >due to some minor technical detail? I don't think that would be a wise thing to do. The motor firing has be done at a precise time with the spacecraft in the proper attitude. If the hammering was done during the motor firing, and the antenna was to pop open, it could change the spacecraft attitude enough to really mess up the orbit insertion. Besides, the spacecraft will very busy as it is during the orbit insertion, collecting the probe data, performing a 1000 km Io flyby and collecting science data on Jupiter. ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Every once in a while, /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | try pushing your luck. |_____|/ |_|/ |_____|/ | ------------------------------ Date: 27 Jan 1993 17:22:00 GMT From: Chuck Shotton Subject: Galileo update? Newsgroups: sci.space In article <27JAN199316252809@kelvin.jpl.nasa.gov>, baalke@kelvin.jpl.nasa.gov (Ron Baalke) wrote: > > I don't think that would be a wise thing to do. The motor firing has be > done at a precise time with the spacecraft in the proper attitude. If the > hammering was done during the motor firing, and the antenna was to pop > open, it could change the spacecraft attitude enough to really mess up the What's to say it won't pop open anyway? > orbit insertion. Besides, the spacecraft will very busy as it is during > the orbit insertion, collecting the probe data, performing a 1000 km Io flyby > and collecting science data on Jupiter. Will there be an attempt to open the antenna AFTER Galileo is in orbit (on the assumption that the firing may have jarred things loose)? ------------------------------ Date: 27 Jan 1993 12:15:19 -0600 From: Harold Neal Subject: JIAFS Newsgroups: sci.space Does anyone have any experience with the graduate program of the Joint Institute for Advancement of Flight Sciences at Nasa/Langley, run by George Washington University? I'd hope to here about from someone who has been part of it. ------- ------- Harold Neal evlhn@vtvm1.cc.vt.edu Engineering Mechanics, Virginia Tech ------------------------------ Date: Wed, 27 Jan 1993 08:07:31 GMT From: Henry Spencer Subject: Lubrication problem (was Re: Galileo Stuck Ribs / Remote Manipulator?) Newsgroups: sci.space,sci.astro,alt.sci.planetary In article <1993Jan14.175452.1@fnala.fnal.gov> higgins@fnala.fnal.gov (Bill Higgins-- Beam Jockey) writes: >> Who told you that loss of lubricant was the problem? How about a >> broken or cracked rib, or some other less obvious reason for the >> jam? > >Loss of lubricant during truck travel is the best guess of Galileo's >engineers... It's important to note, though, that it remains only a theory, not an established fact. What's more, this theory seems rather low in predictive power: the same folks who told us that loss of lubricant was probably the failure mode also told us that the heating/cooling turn sequence would probably work the stuck ribs loose. It didn't. This is not to say that I have any better ideas, but do bear in mind that the hard evidence is slim and our experience with such failures essentially nonexistent. -- "God willing... we shall return." | Henry Spencer @ U of Toronto Zoology -Gene Cernan, the Moon, Dec 1972 | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 27 Jan 93 12:43:51 GMT From: Philippe Colbach Subject: Nasa Press Kit Newsgroups: sci.space How do I order Nasa's press kits? Philippe ------------------------------ Date: 27 Jan 1993 16:09:07 GMT From: Jim Lawson Subject: Nasa Select contact req ? Newsgroups: sci.space Bill Higgins-- Beam Jockey (higgins@fnalf.fnal.gov) wrote: : In article <1k4avqINNmt9@lynx.unm.edu>, lawson%ssdvax.decnet@lbgwy.mdc.com (Jim Lawson) writes: : > My cable company is now under the impression that they need "permission" : > to broadcast Nasa Select. : > Do they ? : No. The government produces it and it's in the public domain. : It *is* reasonable for the cable company to ask for written assurance of this. : (From a source more authoritative than Bill Higgins, I mean.) Kind of what I'm thinking, it might be my cable companys way of putting me off. : > Who can I contact at Nasa Select to straighten this out ? : This question has come up before-- should be in the FAQ-- but I don't : have the answer handy. Call the Public Affairs Office at NASA : Headquarters and try to find out. (202)453-8400. If you get the : answer, post it! Thanks, I rang that number but it has been changed to (202)358-1600. I called that and they referred me to (202)358-1757. I left a message and am awaiting a call back. -- Jim Lawson Lawson%ssdvx1.decnet@lbgwy.mdc.com Alt: Lawson@netsun.mdc.com or Lawson@bbs.ug.eds.com Opinions/Comments expressed here are my own and no one elses !! ------------------------------ Date: Wed, 27 Jan 1993 07:02:42 GMT From: My name is Nasser Abbasi Subject: Orbital Mechanics--Careers? Newsgroups: sci.aeronautics,sci.research.careers,sci.space,soc.college.grad In article <1jqitsINN48q@geraldo.cc.utexas.edu>, mjones@ccwf.cc.utexas.edu (mark jones) writes... > >After u.g. major in math with lots of physics I'm trying to decide on >masters/Ph.d in math or orbital mechanics. What are the opportunities >in orbital mechanics and will they still be there in 5 or 6 years. >Any advice is greatly appreciated. Reply via net or directly >mjones@ccwf.cc.utexas.edu since defense and aerospace are not doing too well, one would think OM area might not be too hot. is there actually an MS in OM? or is OM studied under control engineering? or mechanical engineering? if however you study physics, you can do both, OM and math and many other things too ;-) \nasser ------------------------------ Date: 27 Jan 1993 15:43:29 GMT From: Doug Mohney Subject: Precursors to Fred (was Re: Sabatier Reactors.) Newsgroups: sci.space In article <26JAN199319493864@judy.uh.edu>, wingo%cspara@Fedex.Msfc.Nasa.Gov writes: [Dennis tries to convince Allen that building hardware and flying it on Spacelab is a good thing] You're talking to someone who wants to burn shuttle and put in its place a made-in-Russia tin can. The wall will give you a better discussion Dennis, since Allen has already made up his mind about the utility of anything (other than Freedom, which is needed to assure the Soyuz/Atlas has a place to go) associated with the Shuttle is patently Evil. I have talked to Ehud, and lived. -- > SYSMGR@CADLAB.ENG.UMD.EDU < -- ------------------------------ Date: Wed, 27 Jan 1993 16:58:12 GMT From: "Allen W. Sherzer" Subject: Precursors to Fred (was Re: Sabatier Reactors.) Newsgroups: sci.space In article <1k6aj1INNgtf@mojo.eng.umd.edu> sysmgr@king.eng.umd.edu writes: >[Dennis tries to convince Allen that building hardware and flying it on >Spacelab is a good thing] No, Dennis it trying to convince me that space stations cannot be built without doing lots of Spacelab flights. Allen -- +---------------------------------------------------------------------------+ | Allen W. Sherzer | "A great man is one who does nothing but leaves | | aws@iti.org | nothing undone" | +----------------------139 DAYS TO FIRST FLIGHT OF DCX----------------------+ ------------------------------ Date: 27 Jan 1993 19:22:24 GMT From: Doug Mohney Subject: Precursors to Fred (was Re: Sabatier Reactors.) Newsgroups: sci.space In article <1993Jan27.165812.6931@iti.org>, aws@iti.org (Allen W. Sherzer) writes: >In article <1k6aj1INNgtf@mojo.eng.umd.edu> sysmgr@king.eng.umd.edu writes: > >>[Dennis tries to convince Allen that building hardware and flying it on >>Spacelab is a good thing] > >No, Dennis it trying to convince me that space stations cannot be built >without doing lots of Spacelab flights. So how do you suggest NASA tests hardware and flight procedures before Freedom goes up? Thirty seconds on the vomit comet don't cut it. I have talked to Ehud, and lived. -- > SYSMGR@CADLAB.ENG.UMD.EDU < -- ------------------------------ Date: Wed, 27 Jan 1993 18:47:27 GMT From: "Edward V. Wright" Subject: Saving an overweight SSTO.... Newsgroups: sci.space In <1jpcvtINNmjh@mirror.digex.com> prb@access.digex.com (Pat) writes: >How about this. ping pong around. HawaII to Ecuador. Ecuador to Spain. >Spain to Tanzania. Tanzania to India, India to Australia, Australia >to Hawaii. >You bounce around and just keep meeting cargos. The problem is, that assumes an equal number of cargoes in all locations, which wouldn't be the case. You'd have a lot of cargoes waiting for you in Hawaii, fewer in India and Australia, practically none in Ecuador and Tanzania. Ideas like this make sense when you're talking about expendable artillery shells, and the emphasis is on maximum performance, but when you're talking about airplanes -- or spaceships -- operational considerations must take precedence. ------------------------------ Date: Wed, 27 Jan 1993 07:33:23 GMT From: Henry Spencer Subject: TPS Systems Newsgroups: sci.space In article mcdaniel@grex.ann-arbor.mi.us (Tim McDaniel) writes: >Wasn't there at least one Chinese satellite that returned film (?) using >a heat shield made of oak? Yes, the Chinese reportedly use chemically-treated oak as an ablative material. Apparently it works pretty well. -- "God willing... we shall return." | Henry Spencer @ U of Toronto Zoology -Gene Cernan, the Moon, Dec 1972 | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Wed, 27 Jan 93 19:07:34 GMT From: Ata Etemadi Subject: Using off-the-shelf-components Newsgroups: sci.space G'Day Are there any companies out there whose off-the-shelf products are space-qualified ? I ask this since a colleague at IKI told me that they had flown many standard PC hard discs as onboard storage devices and had great success. I just wondered what other components might be out there which are standard and space-qualified. I don't imagine for one minute that these components will be chosen for major space missions since they are just not expensive enough. Maybe the UOSAT folks will be willing to give them go... regards Ata <(|)>. | Dr Ata Etemadi, Blackett Laboratory, | | Space and Atmospheric Physics Group, | | Imperial College of Science, Technology, and Medicine, | | Prince Consort Road, London SW7 2BZ, ENGLAND | | Janet atae@uk.ac.ic.ph.spva or ata@uk.ac.ucl.mssl.c | | Internet/Arpanet/Earn/Bitnet atae@spva.ph.ic.ac.uk or ata@c.mssl.ucl.ac.uk | | Span SPVA::atae or MSSLC:atae | | UUCP/Usenet atae%spva.ph.ic@nsfnet-relay.ac.uk | ------------------------------ End of Space Digest Volume 16 : Issue 084 ------------------------------