Date: Sat, 27 Mar 93 05:20:27 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V16 #374 To: Space Digest Readers Precedence: bulk Space Digest Sat, 27 Mar 93 Volume 16 : Issue 374 Today's Topics: 25 kg. to Venus, how much would it cost? (2 msgs) Artificial Gravity How to cool Venus Idle Question In what craft did Glenn orbit the E JPL Instruments Set for STS-56 Life in the Galaxy Luddites in space Magellan Update - 03/22/93 Meteorites on Earth...where did they come from? Predicting gravity wave quantization & Cosmic Noise Space Posters, and where to get them? Space Ship - Outer Space Speculation: the extension of TCP/IP and DNS into large light lag enviroments STS-55 (Columbia) abort (was Aurora?) Why use AC at 20kHz for SSF Power? 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: Fri, 26 Mar 1993 17:05:52 GMT From: Frank Crary Subject: 25 kg. to Venus, how much would it cost? Newsgroups: sci.space In article rabjab@golem.ucsd.edu (Jeff Bytof) writes: >Using existing technology and launch vehicles, what would be the >cheapest way to deliver a 25 kg. payload to the upper Venusian >atmosphere? Putting an aeroentry/heat shield and related equipment would drive the mass up to 40-50 kg. A minimum energy transfer from Earth would require (overall) a 4.5 km/s delta-v for an object in Low Earth Orbit. Allowing another 50 kg or so for the rocket and fuel tankage, and assuming a rocket with about 300 seconds of impulse (typical for a good, small rocket), you'd need perhaps 500 kg of fuel. So, adding it all up, a 25 kg package to Venus would require about 600 kg IMLEO. The cheap way to launch that would be either Pegasus or a Scout. With a Scout, you would be well under the vehicle's capacity: You'd be more efficient if you sent a larger (~50kg) package, or sent two... Frank Crary CU Boulder ------------------------------ Date: Fri, 26 Mar 1993 17:19:13 GMT From: Keith Mancus Subject: 25 kg. to Venus, how much would it cost? Newsgroups: sci.space In article , henry@zoo.toronto.edu (Henry Spencer) writes: > For maybe $15M you can get Pegasus plus a spin-stabilized kick motor, > which will give you about 75kg to Earth escape... > For not a lot more, maybe $20M, you should still be able to buy a > Molniya launch from the Russians: 1700kg (!) to Earth escape... Sounds to me like there is a LOT of room for cost improvement on the low-mass end, unless the $20M figure is really a loss to the Russians and they just don't know it (quite possible). 20E6 / 1.7E3 = 11.8E3, or 11.8K $/lb. 15E6 / 75 = 2E5, or $200K/lb. At $12K/lb, the Molniya price, the 75 kg would cost $900K. It seems to me that a cost of < $1M per launch would have a great effect on the viability of this type of mission. Granted, there are some benefits to scale here, but I don't believe that decreases cost by a factor of 10. I wonder what a Russian-built Pegasus-class launcher would cost? -- | Keith Mancus | | N5WVR | | "Black powder and alcohol, when your states and cities fall, | | when your back's against the wall...." -Leslie Fish | ------------------------------ Date: Fri, 26 Mar 1993 13:56:32 GMT From: Nick Szabo Subject: Artificial Gravity Newsgroups: sci.space henry@zoo.toronto.edu (Henry Spencer) writes: >You've missed a point: where is the *requirement* for it? > [artificial gravity] You've missed a point: where is the *requirement* for astronauts? Most of the astronaut program is justified by "life sciences" research, which is predicated on an alleged major need for astronauts in the future. What will they be necessary for in the future, if anything? If the answer to this includes the moon or Mars, then there is probably a need for artificial gravity to test out long-duration adaptation of mammals to these gravity levels, as well as the concern about long durations on flights to the Mars, asteroids, etc. -- Nick Szabo szabo@techboook.com ------------------------------ Date: Fri, 26 Mar 1993 17:17:28 GMT From: Michael Robert Williams Subject: How to cool Venus Newsgroups: sci.space Some of the topics getting tossed back and forth are quite interesting; I especially liked the idea of making it *snow* on Venus. But, to the point, several people have been talking about using large nuclear bombs (should that be "tools"?) to blast a large fraction of Venus's atmosphere away. I read a really fascinating book a few years back called "ThPhysical Principles of Thermonuclear Explosive Devices" that had a chapter called "On Creating Thermonuclear Explosives of Arbitrarily Large Size." It seemed pretty easy, at least conceptually; the author even says something about blowing most of the atmosphere of the Earth away with a suprisingly small bomb. Does anybody with more experience in the field than I have (i.e. any at all) have any idea if this sort of thing is truly possible, or was the author improperly scaling his results? In Real Life:Mike Williams | Perpetual Grad Student e-mail :mrw9e@virginia.edu| - It's not just a job, it's an indenture --------------------------------------------------------------------------- "If you ever have a world of your own, plan ahead- don't eat it." ST:TNG ------------------------------ Date: Fri, 26 Mar 1993 16:08:58 GMT From: Gary Coffman Subject: Idle Question Newsgroups: sci.space In article henry@zoo.toronto.edu (Henry Spencer) writes: >In article flb@flb.optiplan.fi ("F.Baube[tm]") writes: >>How much weight would I get to lob into LEO ? > >My copy of the Scout user manual is at home, but typically it's a few >hundred pounds, as I recall. Scout is rated at 475 pounds to a 300 km orbit. It has lofted as much as 522 pounds to LEO. Gary -- Gary Coffman KE4ZV | You make it, | gatech!wa4mei!ke4zv!gary Destructive Testing Systems | we break it. | uunet!rsiatl!ke4zv!gary 534 Shannon Way | Guaranteed! | emory!kd4nc!ke4zv!gary Lawrenceville, GA 30244 | | ------------------------------ Date: Fri, 26 Mar 1993 16:45:58 GMT From: Henry Spencer Subject: In what craft did Glenn orbit the E Newsgroups: sci.space In article loss@fs7.ECE.CMU.EDU (Doug Loss) writes: >Sorry, Tom, Glenn's capsule was called Friendship 7. That was an >official NASA name; they stopped using names for spacecraft with Gemini. >The names for all the Apollo command and lunar modules were in fact >radio call signs, non-official designations to make communications >easier. Not quite right. All the Mercury capsules had names. The first Gemini capsule had a name too, but it's not mentioned much because NASA did not like it *at all*: Grissom dubbed it "The Unsinkable Molly Brown", in reference to the way his Mercury capsule sank. The next Gemini crew had pencilled in "American Eagle" for their capsule, but at that point NASA decided "no more names". However, they were forced to reverse this during Apollo, when they were maneuvering two spacecraft and needed radio callsigns. The Apollo 9 names, Gumdrop and Spider, were unofficial inventions of the astronauts, but after that the names were official again (mostly because NASA decided that it could at least exercise some control over official names). -- All work is one man's work. | Henry Spencer @ U of Toronto Zoology - Kipling | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 26 Mar 1993 17:23 UT From: Ron Baalke Subject: JPL Instruments Set for STS-56 Newsgroups: sci.space,sci.space.shuttle,sci.geo.meteorology From the "JPL Universe" March 26, 1993 ACRIM, ATMOS set for shuttle flight By Karre Marino As part of NASA's Mission to Planet Earth series, JPL's Atmospheric Trace Molecule Spectroscopy (ATMOS) and the Active Cavity Radiometer Irradiance Monitor (ACRIM) will be on board the Space Shuttle Discovery, when it is launched sometime during the early part of April. The two instruments will study the chemical composition of the atmosphere and how it is changing, and will measure solar variations and their impact on the earth's climate, respectively. ATMOS, which is intended to fly aboard the shuttle about once every year, uses a technique called infrared solar occultation spectroscopy, which Mike Gunson, ATMOS' principal investigator, described as "taking sunlight -- and particularly sunlight at infrared wavelengths -- to create a spectrum. "As the sun's rays pass through the earth's atmosphere at sunset or sunrise, the sunlight is absorbed by gases in the atmosphere," Gunson said. "If you can produce a spectrum, you can see how much of that infrared sunlight is absorbed at different wavelengths and characterize which trace gases and how much of these gases is present in the atmosphere." Gunson, from the Atmospheric and Oceanographic Sciences Section 322, indicated that the window of opportunity is small. "During each orbital sunrise or sunset, ATMOS must take a very rapid series of observations. Since the sun's rays begin well above the Earth, and take just a few minutes to go behind the Earth," he explained, "we try to get about 100 measurements in two to three minutes." Even in such a constrained time period, Gunson said the team gathers "a huge volume of data." Each of these measurements is a high-resolution infrared spectrum containing some million points of data. And through each mission, Gunson said tens of gigabytes of data are accumulated. ATMOS will focus on the middle atmosphere ("from a few kilometers above us up to 150 kilometers") to discern how its composition is changing. "We want to measure as many different gases as we can," he said. "The trace gases -- those over and above nitrogen and oxygen -- include chlorofluorocarbons; measuring these will enable us to learn what processes in the stratosphere turn them into inorganic chlorine and how exactly this happens." While ATMOS does not measure chlorine monoxide, the gas directly involved in ozone destruction, it does measure the other forms of chlorine-containing gases. "So what we have from an experiment like ATMOS is a snapshot inventory of what's in the stratosphere. We can use these vertical-distribution profiles for each of these gases to help modelers to predict how the atmosphere will change." Gunson said that gathering the information creates a reference point for future comparisons, "which tells us how the atmosphere is changing." ATMOS first flew in 1985 aboard Spacelab 3 and flew in a second mission in March 1992 aboard Atlas I. Important data were gathered during both flights. "Looking at these measurements, we have seen distinct changes in the atmosphere's composition." Those changes are not always a result of man. Gunson described last year's eruption of Mt. Pinatubo in the Philippines as providing the perfect opportunity to study how such natural occurrences affect the atmosphere. "Nine months after the volcano blew -- the biggest eruption of the century -- it was still spewing bits of material into the environment," he said. "The volcanic residue created an aerosol layer of fine droplets of sulfuric acid and water in the lower atmosphere. Of course, it was purely serendipitous that the volcano erupted, and we're able to measure its effects." Gunson said history has shown that large volcanic eruptions have an effect on climate; why is only partially understood. "Pinatubo caused changes in the mean temperature worldwide," he explained, noting that a National Oceanographic and Atmosphere Administration analysis indicated a slight cooling trend. The aerosol layer will last a year to 18 months, then will precipitate out. However, he expects some longer-term effects. In the future, Gunson and his team would like to launch during the fall, which allows them to look at the Antarctic, "where we know we'll find some very interesting chemistry going on." He said the importance of ATMOS is seen in repeating these measurements over a decade or longer. "We provide measurements that the scientific community at large can pull together and make sense of. Our overall goal is to gather data with all these different settings -- solar output, the state of the atmosphere. This is part of NASA's large-scale program to which we all make our own small contribution." Making its own contribution is the ACRIM instrument, which will monitor and verify total solar irradiance (TSI) variability, providing reference comparisons with other solar monitors on satellites that are required to understand the sun's long-term behavior. According to Dr. Richard Willson, principal investigator of the ACRIM experiments, the earth's climatological mean is determined solely by how much of the sun's radiant energy -- our only source of heat and light -- falls on the planet's surface, oceans and atmosphere. The Atlas/ACRIM results, he said, will assist researchers in understanding the role of TSI variability in climate change. While JPL currently has the ACRIM II instrument on the Upper Atmosphere Research Satellite (UARS), "instruments on other satellites and/or the shuttle are required for comparisons with the results of ACRIM II to provide backup observations," Willson said. This comparative/backup role played by ACRIM's upcoming shuttle mission is helpful in several ways, Willson said. Most importantly, if the currently operating UARS/ACRIM II should cease functioning before ACRIM III is launched (projected for 2002), the shuttle ACRIM results would be used to compare UARS/ACRIM II and ACRIM III. "The ACRIM instrumentation," Willson said, "although state of the art in the solar-measurement field, is not sufficiently accurate to sustain the required long-term precision in the TSI database should an interruption in the train of succeeding satellite monitors occur." Willson said sustained changes in TSI of "as small as 0.5 percent per century" could cause all the climate variability known to have occurred in the past, and to detect solar variability at that small rate requires that the long-term TSI variability database be constructed with a precision equal to the in-orbit precision of the monitoring instrumentation. The only way to obtain this precision, he said, is to compare succeeding satellite solar monitors directly or compare both of them with an experiment like ACRIM. Willson, who works in the Atmospheric and Oceanographic Science Section 324, and his team are interested in the shuttle ACRIM observations, which he termed as "third-party experiments that can relate one satellite's of results to another's at the level of precision defined by all three instruments." Willson said the ATLAS/ ACRIM instrument's results, although just snapshots of TSI during week-long missions once per year, will thereby contribute to an understanding of the long-term database. "Solar monitoring by the first ACRIM experiment on the Solar Maximum Mission from 1980-89 showed that there is a solar cycle component of variability: TSI is directly proportional to solar magnetic activity, demonstrating an 0.1 percent peak-to-peak variation over solar cycles 21 and 22 (the last sun spot cycle). That in itself may be too small to have an observable effect on climate," he said, "but we're interested in whether this little 0.1 percent `wiggle' over a solar cycle is superposed on longer-term, larger-amplitude variability. Periods of 80 to several hundred years are suspected to exist with amplitudes of 1 percent or more. TSI variability is suspected to have caused known past climate changes on these time scales." Willson noted, however, that such subtle changes in TSI will be very difficult to detect since the results of many satellites' instruments must be used over many decades or even centuries to prove definitively that solar variability causes climate change. The only hope of providing a sufficiently precise TSI database over these time scales, he said, is to relate the results of solar-monitoring experiments at the level of instrument precision, which is orders of magnitude smaller than instrument accuracy. While this is ACRIM's third shuttle flight, Willson said that they have yet to determine whether the shuttle experimental environment will be adequate for the task of providing "third-party" observations. "We have had our share of problems trying to make good measurements aboard the shuttle," he said. "The first attempt was as part of the Spacelab 1 Mission in 1983, and the large array of experiments on board overwhelmed shuttle resources. Additionally, some of the untested, new shuttle instrumentation experienced mechanical and electrical problems. "Our ACRIM experiment functioned flawlessly, but it was attached to an ESA-provided command/data interface that ceased functioning when it was warmed by the sun. This resulted in our getting only an hour's worth of data when we'd been expecting about 25 hours," he added. Willson said that on ACRIM's second flight, aboard Atlas I, the shuttle systems functioned well, as did ACRIM, and a full set of results was acquired. "We made real-time comparisons with the UARS/ACRIM II experiment, providing a potentially useful reference point for the future." The upcoming Atlas II mission "should help us tie down the quality of observations we can expect from ACRIM in the shuttle environment." Willson said data will be received in real time, as they "pull it straight off the downlink, crunch the numbers and offer feedback to the Marshall Space Flight Center in Huntsville, Ala. We will have results within minutes of the actual measurement," he said. "Both climatologists and solar physicists are keenly interested in variations of TSI. Those monitoring the impact of increasing `greenhouse gases' on the earth are especially concerned." ### ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't ever take a fence /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | down until you know the |_____|/ |_|/ |_____|/ | reason it was put up. ------------------------------ Date: Fri, 26 Mar 1993 17:03:10 GMT From: Michael Robert Williams Subject: Life in the Galaxy Newsgroups: sci.space,alt.sci.planetary It's fortunate that Mars isn't in the so-called "life zone" of our Sun; didn't any of you see/read/hear "The War of the Worlds"? It's unfortunate that Venus isn't in the life zone of the Sun; didn't any of you see "Half-Naked Amazons from Venus"? In Real Life:Mike Williams | Perpetual Grad Student e-mail :mrw9e@virginia.edu| - It's not just a job, it's an indenture --------------------------------------------------------------------------- "If you ever have a world of your own, plan ahead- don't eat it." ST:TNG ------------------------------ Date: 26 Mar 1993 12:27:58 -0500 From: Pat Subject: Luddites in space Newsgroups: sci.space,talk.politics.space In article <1993Mar25.204904.4885@mksol.dseg.ti.com> mccall@mksol.dseg.ti.com (fred j mccall 575-3539) writes: >I hardly ever 'ignore economics', since I went to the trouble and >effort to get a degree in the subject so I would understand things >that to you are apparently beyond comprehension. Perhaps you should And DOug Mohney in a previous Post How much do I know about Economics, I have a degree in the subject. SO who else has a degree in economics? Pat Who didn't bother, because i already know the field. ------------------------------ Date: 26 Mar 1993 12:36:42 -0500 From: Pat Subject: Magellan Update - 03/22/93 Newsgroups: sci.space,sci.astro,alt.sci.planetary I have never studied the magellan design data, so I am operating blindly, But if the Radar emitter is separate from the x-Band downlink transmitters, I thought they were the same devices, Then is there some way of coding into the Radar emission, and using that to transmit back data, when the Last transmitter goes? Evena simple morse-pulsing. Certainly, low rate, but good for filling in some of those remaining blank spaces that magellan never imaged. That's only about 1% of the the surface. pat ------------------------------ Date: 26 Mar 93 17:51:24 GMT From: David Lai Subject: Meteorites on Earth...where did they come from? Newsgroups: sci.space Hi netters, I know that there're some meteorites which were found in the South Pole area has been identified as Moon and Mars rocks. My question is how do they know that they are from Moon and Mars? I think they compare the rock samples that carried back from Moon/Mars and the mete- orities found on Earth. But, did we ever bring back any rock samples from Mars???? David. ------------------------------ Date: Fri, 26 Mar 1993 16:19:38 GMT From: Gary Coffman Subject: Predicting gravity wave quantization & Cosmic Noise Newsgroups: sci.space,sci.astro,sci.physics,alt.sci.planetary In article mcirvin@husc10.harvard.edu (Matt McIrvin) writes: >gary@ke4zv.uucp (Gary Coffman) writes: > >>Why would there be an amplitude change? The EM wave is transverse, >>the G wave is compressive. > >Compressive? I thought gravitational waves were transverse quadrupole >oscillations. The oscillating tidal forces are transverse to the >direction of motion of the wave. I could write a book on what I don't know about gravity waves. I'm taking a classical approach to the problem, which may be all wet. If your description is accurate, then a G wave perpendicular to the line of flight of the EM wave would have the largest effect, and a wave along the line of flight would be undetectable. In any event, I'm suggesting that the oscillating force alternately stretches and compresses the ether (fabric of spacetime, whatever). Gary -- Gary Coffman KE4ZV | You make it, | gatech!wa4mei!ke4zv!gary Destructive Testing Systems | we break it. | uunet!rsiatl!ke4zv!gary 534 Shannon Way | Guaranteed! | emory!kd4nc!ke4zv!gary Lawrenceville, GA 30244 | | ------------------------------ Date: 26 Mar 93 11:23:38 -0600 From: Bill Higgins-- Beam Jockey Subject: Space Posters, and where to get them? Newsgroups: sci.space In article <1993Mar25.102746.1@aurora.alaska.edu>, nsmca@aurora.alaska.edu writes: > Wiers question, where is a good place to get Space Posters??? I know that many > people seem to like posters of movie stars and such, beer (sexy girls okay), > and other such things, I was wondering if someone has any Space Posters and > where to get them? Check the sci.space FAQ for sources to start with. You can buy some nice space posters from the U.S. Government Printing Office bookstore. Voyager images and the Shuttle figure heavily. Aaarrggh! We don't have a USGPO address in the FAQ, though we refer to it several times! They have local bookstores in many cities, though none in Alaska (sorry, Mike). Ask them for specialized catalogues of space and astronomy stuff as well as their general catalogue. U.S. Government Printing Office MAin Office 710 N. Capitol St. Washington, D.C. 20402 (202)275-2091 Public Affairs Offices at NASA centers may send you a poster or two if you ask politely. Addresses are in the FAQ file. The SEDS people have made some delightful posters for their conferences. Mail a message to SEDS-L@TAMVM1.TAMU.EDU asking them to e-mail information. Ask about the California 1989 "Space Surfing" poster! I've gotten nice posters from ESA at conferences, but I haven't seen a catalogue. Try the U.S. office first, but also write to their Publications Office in the Netherlands. EUROPEAN SPACE AGENCY (ESA) 955 L'Enfant Plaza S.W. Washington, D.C. 20024 (202)-488-4158 Distribution Office ESA Publications Division ESTEC Kelplerlaan 1 2200 AG Noordwijk The Netherlands Most space companies have posters publicizing their projects. Boeing, TRW, Martin Marrietta, Lockheed, etc. Check a magazine or directory for their addresses. Check ads in *Ad Astra*, *Space Frontier*, *Astronomy*, and *Sky & Telescope*. PlanSoc has some items for sale. Planetary Society 65 North Catalina Avenue Pasadena, California 91106 And if you find one with a sexy girl movie star drinking beer in front of a spacecraft, let me know! -- O~~* /_) ' / / /_/ ' , , ' ,_ _ \|/ - ~ -~~~~~~~~~~~/_) / / / / / / (_) (_) / / / _\~~~~~~~~~~~zap! / \ (_) (_) / | \ | | Bill Higgins Fermi National Accelerator Laboratory \ / Bitnet: HIGGINS@FNAL.BITNET - - Internet: HIGGINS@FNAL.FNAL.GOV ~ SPAN/Hepnet: 43011::HIGGINS ------------------------------ Date: 26 Mar 93 17:57:25 GMT From: David Lai Subject: Space Ship - Outer Space Newsgroups: sci.space Hi netters, I remember that a spacecraft was around the nineth planet some years ago. Is there any spacecraft travelling beyond the nineth planet now? If so, what discovery has it make? Can it still communicate with the Earth? David. ------------------------------ Date: 26 Mar 1993 18:23:47 GMT From: "M. Sean Bennett" Subject: Speculation: the extension of TCP/IP and DNS into large light lag enviroments Newsgroups: alt.internet.services,sci.space As man moves outward into space it will become essential to provide an information structure for communication of data. The current set of protocols make no alowance for light 'lag' between targets of wide divergence. (Mars-Earth). The current DSN is expensive to use for continous data flow. If however we could use a series of store and forward systems for data - we have no mechanism to ensure that the data is delivered securely (Appart from ad-hoc protocols constructed by NASA). We need some form of ISO standard (I know they are hard to set, but if NASA/GlavCosmos publish a protocol it will be the defacto standard) How are we to devide the domains to deal with other worlds? (yes I know this sounds mad - but if we have not made some form of descision we will have moonbase.nasa.gov - implictly making that instalation part of the USA..a dangerous precedent) These are just my random thoughts. I make no claims that they hold great thought or meaning. biff@base-camp.olympus-mons.mars Sean ------------------------------ Date: Fri, 26 Mar 1993 16:03:51 GMT From: Gary Coffman Subject: STS-55 (Columbia) abort (was Aurora?) Newsgroups: sci.space In article henry@zoo.toronto.edu (Henry Spencer) writes: >In article <1993Mar25.011212.9759@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes: >>... So liquid or solid, once you light the >>boosters, you're committed to getting enough altitude to do a RTLS. The >>holddowns can't keep the Shuttle on the pad against both main engines and >>boosters. > >There's no good reason why they couldn't. The Saturn V holddowns could, >and did. And they didn't even use pyrotechnic release -- they were 100% >mechanical. Yeah, but how much re-engineering would be involved, not just to the pad, but to the Shuttle structure as well? Beefing the pad is relatively easy, and I guess the new holddowns could be on the boosters rather than the Shuttle structure, but it would be a nasty problem. On the other hand, if liquid boosters were used (in your dreams), the extra holddowns would be *necessary*. Unlike the solids, liquid boosters could suffer the same kinds of problem that caused the SSME shutdown. Having a booster shutdown during liftoff would be too much to handle. Gary -- Gary Coffman KE4ZV | You make it, | gatech!wa4mei!ke4zv!gary Destructive Testing Systems | we break it. | uunet!rsiatl!ke4zv!gary 534 Shannon Way | Guaranteed! | emory!kd4nc!ke4zv!gary Lawrenceville, GA 30244 | | ------------------------------ Date: 26 Mar 1993 12:42:33 -0500 From: Pat Subject: Why use AC at 20kHz for SSF Power? Newsgroups: sci.space In article <1993Mar24.180140.28433@mksol.dseg.ti.com> mccall@mksol.dseg.ti.com (fred j mccall 575-3539) writes: > >But not nearly as weight conscious as spacecraft have to be. In >addition, needs are somewhat different between an aircraft and a space Yeah,fred. The difference is that aircraft have to fly. >station. Personally, I think 20kHz was a bad idea, but I also think >that this insistence of yours that if it was good enough for the >Wright brothers it's good enough for SSF is just a bit silly. Don't try to misrepresent my position, fred. It's intellectually dishonest. I am all for 20KHz power as part of a engineering research and developement test bed. TO make it the defined Prime power on an OPERATIONAL station is absolutely stupid. You just can't believe that someone wwants to see proven trackrecord before commiting a 40Billion dollar program. pat ------------------------------ End of Space Digest Volume 16 : Issue 374 ------------------------------