Date: Sun, 21 Mar 93 05:00:14 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V16 #346 To: Space Digest Readers Precedence: bulk Space Digest Sun, 21 Mar 93 Volume 16 : Issue 346 Today's Topics: Aurora spotted ? (2 msgs) CD for Pluto Mission Clueless Szaboisms (Was Re: plans, and absence thereof) (2 msgs) How to cool Venus (2 msgs) Just a little tap (was Re: Galileo HGA) Magellan Update - 03/19/93 (2 msgs) Predicting gravity wave quantization & Cosmic Noise SR-71 Maiden Science Flight SSTO: A Spaceship for the rest of us tether II Water Simulations (Was Re: Response to various attacks on SSF) Why use AC at 20kHz for SSF Power? (2 msgs) will dust cool Venus? 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: Sat, 20 Mar 93 14:21:41 GMT From: Dean Adams Subject: Aurora spotted ? Newsgroups: sci.space lc2b+@andrew.cmu.edu (Lawrence Curcio) writes: >A Mach 8 spy plane is certainly not ordinary either. No, but a Mach 6 version might be "ordinary" to those cleared into a certain Special Access Program... :-> >UFO reports are - that was my original point. Dime a dozen... >It strikes me that the evidence/arguments for the AURORA are >no stronger than those for UFO's, Ha! Not by a *longshot*, unless the "UFOs" you are talking about are the product of Lockheed's Skunk Works. You can talk about "alien invasions" until you are blue in the face, and the "evidence/arguments" will never add up to what you can find connected to a certain facilities in Burbank and Palmdale... >yet UFO's are (rightly or wrongly) dismissed out of hand, Sometimes... >and the AURORA is (rightly or wrongly) embraced - by the same >group of individuals. It is "embraced" by many people who follow these types of programs. "UFO's" don't need to have anything whatsoever to do with it. >In fact, now we have a rule that says: >1) If a sighting can be a UFO sighting or an AURORA sighting, >it's an AURORA sighting; Just WHAT "aurora sightings" are you referring to? There are only a couple of documented examples of such incidents in the first place. >2) If the sighting cannot possibly be an AURORA sighting, dismiss it. What are you talking about? Unlike the ufo world, there are NO such wholesale barrages of "aurora sightings" around. >Don't mistake me for a UFO advocate; I am merely impressed by the >social dimension of what passes for common sense. Hmmm... I am more impressed (depressed) by social dimensions that often seem to seriously LACK common sense... >IMHO, we should be consistently skeptical of *ALL* sightings >noises and rumors, Makes sense. >but allow room in our philosophies for extraordinary >things - even Mach 8 spy planes. BUT, a Mach 6 spy plane is VASTLY less extraordinary than "alien invaders". This is a good example for using common sense. That same common sense, combined with logic and various evidence, says there very likely *IS* a high-mach SR-71 follow-on vehicle operating. And NONE of that is anthing even remotely connected with "UFOs". ------------------------------ Date: Sat, 20 Mar 1993 12:43:55 -0500 From: Lawrence Curcio Subject: Aurora spotted ? Newsgroups: sci.space In reply to Dean Adams: The UFO folks are certain that the "Information" they have is reliable as well. Reliability is a value judgement that is, in part, socially based. I wish to thank Mr. Adams for his demonstration of my point, and as a token of my appreciation, I also vouchsafe him the last word in the exchange. -Larry C. ------------------------------ Date: 20 Mar 93 15:29:06 GMT From: FRANK NEY Subject: CD for Pluto Mission Newsgroups: sci.space In article <1993Mar19.192249.6924@csus.edu> arthurc@sfsuvax1.sfsu.edu (Arthur Chandler) writes: > > Someone refresh my memory: what was in the last "message in a bottle" >spaceship (I seem to recall a diagram of the solar system, drawings of a >man and a woman, etc.), and what form (paper, record, videotape, etc.) >did it take? What you describe was the plaque on the Pioneer probes. It was (I believe) etched on gold. The Voyayer probes contained a record and stylus, plus instructions on the cover on how to extract information from it. If you can find a record or book called 'Sounds of Earth,' this is the content of that record. What I was contemplating was a CD-ROM using most of the scientific information from 'Sounds of Earth' as a starting point. -- The Next Challenge - Public Access Unix in Northern Va. - Washington D.C. 703-803-0391 To log in for trial and account info. ------------------------------ Date: 20 Mar 1993 09:51:55 -0500 From: Pat Subject: Clueless Szaboisms (Was Re: plans, and absence thereof) Newsgroups: sci.space,talk.politics.space Dennis, You work on staff for the University of Alabama Huntsville these days right? So forst Dennis gets to deal with typical low university pay. That army of Undergrads at minimum wage depresses everyone elses wages. Second any contracts they get at UAH, first come through a NASA center, with it's overhead 30% according to allen, and then the university takes it's Overhead charge 50-60 % if my figures are anywhere near current. leaving dennis to wrok on a prject with 1/3 the allocated funds. It's these kinds of overheads that are destroying projects. pat ------------------------------ Date: 20 Mar 1993 12:00 CST From: wingo%cspara.decnet@Fedex.Msfc.Nasa.Gov Subject: Clueless Szaboisms (Was Re: plans, and absence thereof) Newsgroups: sci.space,talk.politics.space In article <1ofb2bINN87r@access.digex.com>, prb@access.digex.com (Pat) writes... > >Dennis, > > You work on staff for the University of Alabama Huntsville >these days right? So forst Dennis gets to deal with typical low >university pay. That army of Undergrads at minimum wage depresses >everyone elses wages. Second any contracts they get at UAH, first come >through a NASA center, with it's overhead 30% according to allen, >and then the university takes it's Overhead charge 50-60 % if my figures >are anywhere near current. leaving dennis to wrok on a prject with >1/3 the allocated funds. > >It's these kinds of overheads that are destroying projects. First of all I have two different lives here. First I work on "official" UAH contract efforts such as SpaceHab, Spacelab, CONSORT, COMET etc... (by the way I have a payload on each of these misions in the next year or so) then there is my SEDSAT 1 work. On the NASA contract side we have won contracts because we are consistently cheaper than anyone else and we get the job done. The reason that my contract pay is low is that I have a 2 year degree in a University town environment. A 2 year degree and a cup of coffee are both worth 50 cents here. My SEDSAT 1 work is at this time funded 40% and as of next month be 100%. This is money that I personally go out and raise. The University takes no overhead from this money as their contribution to our project. The standard university overhead on fully burdened efforts is 36.6%. This is marginally less than the typical mark up of 40% in the commercial retail world. This margin is what typically is profit in the real world. However If I do contracts and they are fully burdened we still get 4% of the money back in what is called incentive funds. This is for new projects or any darn thing we want to spend the money on. There are very few undergrads working in research at a meaningful level around UAH besides me and a couple of others. The technical disciplines that are used simply preclude this type of labor. In general university salarys are lower than the private sector but there are other compensations for that. As for the clueless post that someone else made. I do this because this is where our future is. I cannot help that the Szabos and others out there are looney toons and scream at the top of their lungs about their pet projects. Mony is easy to make in this world and I have made it and spent it. There is more to this life than money and there is more to life than screaming at the top of one's computer lungs over sci.space. The human race is at a threshold and a choosing point. We can either turn inward as the Jane Fonda's and Ted Turner's and their ilk want us to do and turn our lives over to "those who know better" or we can turn outward and take our future into our own hands as our ancestors have for thousands of years. This network and the people who post here are for the most part intelligent and have strong convictions: However there is a fatal flaw that I see here and that is you never consider the other interests groups views. We rant and rave here over the whys' wherefore's and whatnot's and never consider that out there in the big world very few care what is going on here because it is not seen as being relevant to the larger problems of the decline of the nation, race relations, crime and the general crazyness of this late 20th century world. It is not that space is not relevant, it is just that not one poster that I have seen on this net addresses their issues within the context of the larger world. This is why I started this thread about "plans and lack therof". This is what Von Braun, Tsivosky, Goddard, Ley and the rest had. They had a plan, they had a vision of what the future could be that was positive, technical but human. Space station is about humans in space. Very few people in this world give a hoot about many of the plans that are put forth on sci.space for the utilization of this or the blast off of that, BUT I submit to you readers that the manned space program has changed more lives for the better than any self help program or psychciatrist (sp) in the world. I have seen and met and work with students that from the age of 3 years old have dedicated their lives to working in space. There is something to this if it can bring forth this level of dedication, motivation, and effort that lasts from babyhood to adulthood. This is why Space Station Freedom is ultimately important. It is a symbol of what can be done, it is a beacon to light the way for the children like myself and many many others who chose this path from our earliest thoughts. It is a faith that we will do good up there. What is that faith based upon? Besides the technical promise that is held out, there is the fact that in every new frontier that mankind has ever embarked upon, the sum total has been the improvment of life for all mankind. Take a look around, get off the terminal for a day or two and read the papers. What other endevaour in this world holds out for a postive future where individual freedom remains? Where you can do your best and make a large contribution? There are 100 billion stars in this galaxy. We are so arrogant to think that all of the answers are here on the earth. From the earliest days of mankind we have learned by looking upward not backward. This is why I post about a plan an a lack thereof. With one exception by a poster that is not a regular, all I have heard is the regurgitation of peoples pet plans with no consideration on how these plans fit in with the larger realm of mankind. Give Allen credit, at least his plan does add to what is a larger plan. Even Nicks plan has a place in the overall pie. BUT neither of you consider what you are doing leads to within the context of HOW this will benefit all mankind. Leaders of an earlier age did this. Edison wanted light to banish the night and free mankind from being a slave to the night. Tesla's dream was to power the machines that would free mankind from drugery and manual labor. Mr. Boeing and Lindberg and all the avaition pioneers saw clearly how the aeroplane would revolutionize travel and trade for the world (and make a buck too!) Von Braun and the others of his ilk were the same. The central problem of this day and this age and this net is that no one is putting forth the dream and then going forth and working on it. If Allen would stop twisting things so much he would be worthy of great admiration. I have changed my mind regarding SSTO during our debates. Come on out there, think about these things and post something. What about me? Well..... just wait and see. Dennis, University of Alabama in Huntsville ------------------------------ Date: 20 Mar 93 12:05:53 GMT From: Del Cotter Subject: How to cool Venus Newsgroups: sci.space Some references: Martyn J Fogg 'The Terraforming of Venus' J. Brit. Interplanetary Soc. _40_ 551-564 Stephen L Gillet 'Second Planet - Second Earth' Analog _104(12)_ 64-78 (1984) 'The Postdiluvian World' Analog _105(11)_ 40-58 (1985) (Translated from Fogg's referencese, I *think* these are the Dec 84 and Nov 85 issues; ICBW) Fogg's paper is still, IMO, a classic for those interested in doing something with our useless sister planet. It wouldn't be easy, mind. Here's how Fogg sees it: Year 0 Project begins; algae injected into Venus atmosphere Importation of 1e17 kg of H2O from Iapetus (for algae) Mining of H2 in Uranus atmosphere begins (to fix the excess O2 produced by photosynthesis and make oceans) Asteroid Psyche moved into Venus orbit Construction of Dyson motor begins 500 Dyson motor in operation 13200 Venus spun up to 24 hour day by Dyson motor Dyson motor dismantled 15200 Algae have reduced all 4.6e20 kg of Venus' CO2 H2 importation ceases at 4.2e19 kg Sunshade constructed at Sun-Venus L1 point Rainout begins 16200 Venus cooled to 300K; 75% of Sunshade dismantled Terraforming begins in earnest 16500 Venus terraformed; total energy expenditure 1e30 J -- ',' ' ',',' | | ',' ' ',',' ', ,',' | Del Cotter mt90dac@brunel.ac.uk | ', ,',' ',' | | ',' ------------------------------ Date: Sat, 20 Mar 1993 17:18:50 GMT From: Gary Coffman Subject: How to cool Venus Newsgroups: sci.space In article <93078.141219GRV101@psuvm.psu.edu> Callec Dradja writes: >In article <1993Mar18.082941.10534@nic.funet.fi>, TMakinen says: >> >>This removing of carbon from primordial atmosphere as a byproduct of the >>chemical processes driven by living organisms is a minor cause to present- >>day lack of carbon dioxide in our atmosphere. The main deposit of carbon >>dioxide in our planet lies in the carbonate rocks which contain some >>100,000 times more CO2 than the atmosphere. CO2 is recycled through >>plate tectonics and volcanism. > >What you say about the carbonate rocks makes sense but what I do not >understand is why the Earth has carbonate rocks and Venus does not. >Are carbonate rocks created by some sort of geological process? Both >Earth and Venus seem to be geologically active so why the lack of >carbonate rocks on venus? Likely it's because the surface temperature is so high that the CO2 is baked out of the rocks before they can be buried by tectonic action. [delete] >I would also like to address the solution that one person offered >of using nuclear devices to blast the atmosphere out into space. This >idea sort of frightens me because such large forces seem sort of >difficult to control. I would be afraid that too much of the atmosphere >might be blown away. In addition, maybe my thinking is wrong but it seems >to me that in the future, if we really start using the resources of >our solarsystem, there may one day be a shortage of oxygen. It makes >more sense to keep it there in one relatively accessible place than to >blast it out into space where it will disperse and be much harder to >recover. Rather than too much of the atmosphere being blown away, I suspect the reverse would be the problem. It would take some *really* big nuclear bombs to blow off 90% of the atmosphere. Certainly bigger than anything we have a clue about building. Maybe some sort of anti-matter bomb would work. It seems to me that the atmosphere problem of Venus is a tougher nut to crack than terraforming about any other minor body in the solar system. Even giving the Moon a breathable, albeit temporary in geologic terms, atmosphere looks like an easier job. 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: 20 Mar 1993 10:02:33 -0500 From: Pat Subject: Just a little tap (was Re: Galileo HGA) Newsgroups: sci.space Oh, the galileo engineering team deserves the Edison Prize for their work in coping with a basically disasterous event. The DSN improvements and the new coding schemes are terrific, but I think 30% is a number placed on for PR purposes, not in any way a real number. The imaging people get hosed, the Fields people do okay, the Probe people do good. pat ------------------------------ Date: 20 Mar 1993 09:55:08 -0500 From: Pat Subject: Magellan Update - 03/19/93 Newsgroups: sci.space,sci.astro,alt.sci.planetary In article <20MAR199302585070@kelvin.jpl.nasa.gov> baalke@kelvin.jpl.nasa.gov (Ron Baalke) writes: >the remaining moves will be complete by March 31st. Significant amounts >of excess paper have been eliminated, and unneeded equipment has been >surplused. What do the above two clauses really mean? What's unneeded equipment, and what's excess paper? was the team drowning in management paperwork before? or were you just more warehouse space. pat ------------------------------ Date: 20 Mar 1993 21:01 UT From: Ron Baalke Subject: Magellan Update - 03/19/93 Newsgroups: sci.space,sci.astro,alt.sci.planetary In article <1ofb8cINN8c8@access.digex.com>, prb@access.digex.com (Pat) writes... >In article <20MAR199302585070@kelvin.jpl.nasa.gov> baalke@kelvin.jpl.nasa.gov (Ron Baalke) writes: >>the remaining moves will be complete by March 31st. Significant amounts >>of excess paper have been eliminated, and unneeded equipment has been >>surplused. > >What do the above two clauses really mean? What's unneeded equipment, >and what's excess paper? was the team drowning in management paperwork >before? or were you just more warehouse space. It just means that the Magellan team has been cut back. The equipment left behind by the previous team members (mainly computers) is being surplused. ___ _____ ___ /_ /| /____/ \ /_ /| 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: Sat, 20 Mar 1993 17:31:42 GMT From: Gary Coffman Subject: Predicting gravity wave quantization & Cosmic Noise Newsgroups: sci.space,sci.astro,sci.physics,alt.sci.planetary In article crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes: > > This points to another question that I had if my first two > were answered. I'll pose it anyway. Let's say a gravitational > wave comes through and whacks a spacecraft (ripples in space, and > all that). For simplicity, we'll think of wavefront normal to the > line connecting the spacecraft and the earth. Presumably the radio > connection then sees a doppler shift due to the 'oscillation'. > Why does the oscillation not identically nullify the doppler shift > all the way back to the receiver owing to the effect of the wave > on the radio signal? Is that the case, and is that why they're > using three craft? Let's look at it another way. The gravity wave deforms the fabric of spacetime. This lengthens the path from Earth to the spacecraft as the wave passes into the beam. This "stretching" of space lengthens the radio waves, IE lowers their frequency. This will happen to both the wave going to the spacecraft, and the wave returning from the spacecraft for a double downward frequency shift. 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: Sat, 20 Mar 1993 19:15:30 GMT From: "Richard A. Schumacher" Subject: SR-71 Maiden Science Flight Newsgroups: sci.space >> The SR-71 can take measurements across a wider area at that >> height, it can also take measurments in day, night and terminator >> between day/night all in 1 flight, i.e. within a short period of >> time. This wide sample space may provide useful information beyond >> what a balloon's sample space would be. >But what if you used TWO balloons, or maybe three. That would solve the >sample space problem at much lower cost. Or would it? Then you'd need two widely separated ground support crews, or three, and would face a greater chance of not getting some of your (possibly expensive) equipment back. Evidently the researchers who have signed on to SR-71 think they're getting a deal. They could just as well have chosen balloons if they'd wanted them. ------------------------------ Date: Sat, 20 Mar 1993 17:06:16 GMT From: Gary Coffman Subject: SSTO: A Spaceship for the rest of us Newsgroups: sci.space In article henry@zoo.toronto.edu (Henry Spencer) writes: >In article <1993Mar18.013020.1791@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes: >>Henry says that DC-Y will mass 800,000 pounds, and that 700,000 >>pounds of that will be fuel. He further says that LOX is $5 a >>pound and represents the bulk of the weight. So ignoring the >>hydrogen's extra handling costs, fuel for a DC-Y flight costs >>$3.5 million dollars... > >Gary, how do you ever run a successful business if you can't read any >better than this? :-) I don't work from memory when the numbers are *my* dollars. :-) >First, and relatively minor, I never quoted any figure for DC-Y's mass. >If you re-read my writeup, you'll find that it uses that number purely >as an arbitrary example, when discussing the implications of mass ratios. Ok, but if the 20,000 pound payload objective is to be met, you make a good case that the mass is going to have to be in that neighborhood. >Second, and more serious, I quoted LOX at five **CENTS** a pound, not >five dollars a pound. Yeah, this is where memory failure entered, I remembered "a few dollars a pound" and "oxygen....5....", but you were discussing different things. So we're down to $35,000 dollars for fuel. That sounds too cheap. Certainly I can't buy welding gas for $0.05 a pound, it's around $0.55 a pound for compressed gas, I'd assume LOX would be higher and LH higher still, and the bulk discount shouldn't be *that* big. Where'd you get that number? 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: Sat, 20 Mar 1993 17:28:26 GMT From: Douglas R Fils Subject: tether II Newsgroups: sci.space sci.space, I found the following file concerning a tether experiment to take place soon (if it hasn't already been done). Can someone provide more information or perhaps even results? Thanks all Doug ------------included text----------------- NASA to Launch Satellite Into Space on 12 1/2-Mile Tether NASA to Launch Satellite Into Space on 12 1/2-Mile Tether Cape Canaveral, Fla. -- NASA and the U.S. Air Force plan to cast a satellite into space on a 12 1/2-mile cord Thursday night less than a year after failing with the experiment. This time the project, dubbed Tether Two, is simpler and 38 times cheaper, the agencies said. The Air Force will launch an unmanned Delta rocket with a military navigation satellite and NASA's tag-along tether experiment. This 12 1/2-mile tether -- just three-hundredths of an inch thick -- is wound around a spool. One end of the polyethylene fiber cord is tied to a 57-pound aluminum box. Everything is mounted on the rocket's second stage, which will be left in an elliptical orbit 115 miles by 448 miles high after boosting the Air Force's navigation satellite, according to the Associated Press. The plan is to pop the spring-loaded box off the spent booster an hour after the 10:55 p.m. launch. As it shoots away, the box should cause the tether to unwind. Instruments on board will record the speed and tension of the tether and send the data to Earth. When the tether is almost fully extended -- if it gets that far -- a brake will slow the unreeling. The cord and box will swing like a pendulum below the booster, and a guillotine-type mechanism will cut the tether. The rope and box will burn up as they enter the atmosphere three hours into the flight. All for $10 million. Compare that with the $379 million tether contraption that flew on the Space Shuttle Atlantis last summer and required seven astronauts for operation and, as it turned out, for help. The ball on the end of the electricity-generating cord never got more than 840 feet from the shuttle because of a protruding bolt that caused the line to jam. NASA has yet to schedule another shuttle mission with the first experiment, Italy's Tethered Satellite. It is being shipped back to Italy next week. "A number of people felt mine should have gone first," Joe Carroll, an entrepreneur from Chula Vista, Calif. who designed the tether deployer flying on the Delta, told AP. He proposed the experiment in 1983. "Obviously if we succeed, tethers are more real," Carroll said. "If two entirely different tether systems both have problems, then it sheds a negative pall over the whole range of proposed applications." Potential applications for tethers include using them to drop experiment- laden capsules from space stations to Earth, generate space station electricity, create artificial gravity, fly atmospheric instruments at altitudes too high for scientific balloons yet too low for free-flying satellites, and change spacecraft orbits. Unlike the tethered satellite, this tether system has no moving reel mechanisms or bolts and therefore nothing to jam. There's also no generating electricity, no human interaction, no bringing the tether and box back intact, and no leaving the cord up there to get tangled around a spacecraft. -- ------------------------------ Date: 20 Mar 1993 09:57:27 -0500 From: Pat Subject: Water Simulations (Was Re: Response to various attacks on SSF) Newsgroups: sci.space Ron, the instruments are in easily serviceable units, but some of the repairs I don't think were planned, such as the the Gyro changeouts and the Solar array replacement. The work may go smoothly, the work on DSCS? or was it a DSP went much better then hoped. pat ------------------------------ Date: Sat, 20 Mar 1993 14:24:06 GMT From: Michael Moroney Subject: Why use AC at 20kHz for SSF Power? Newsgroups: sci.space For whatever it's worth: The vast majority of electronics gear run off voltages other than 120V. So they convert the voltage to the level used, often 12 or 5V. In the olden days this was done with a big power transformer, which would get quite upset at 20kHz. However, most modern gear doesn't use them anymore, they convert the incoming power to a high frequency (often 20kHz), run it through a small "power transformer" that's often a toroid, then rectify to DC as usual. This has the advantage of lighter weight and better filtering with smaller components, often with 120V/240V capability thrown in for sales anywhere. How is this done? Well the first thing done to the power when received is to rectify it to DC. It is chopped with an oscillator. What does this mean? For much stuff it doesn't matter what the frequency is, it can run off DC if needed. And much of the stuff is generating the 20kHz frequency anyway, so you'll have to deal with the noise problem from them. I suppose there could be a minor advantage. One could eliminate the first rectifier/filter/chopper on the 120V side of the toroid xformer and feed the 120V 20kHz directly to the toroid, and save a few parts count, if the device was to be used *only* on 20kHz power. -Mike ------------------------------ Date: Sat, 20 Mar 1993 19:29:34 GMT From: "Richard A. Schumacher" Subject: Why use AC at 20kHz for SSF Power? Newsgroups: sci.space In moroney@world.std.com (Michael Moroney) writes: >What does this mean? For much stuff it doesn't matter what the frequency is, >it can run off DC if needed. And much of the stuff is generating the >20kHz frequency anyway, so you'll have to deal with the noise problem from >them. With the gigantic complication that, instead of being relatively easily confined inside the small metal box of the convertor, you'd then have high voltage AC running all over the station. Can you say "antennas"? Can you say "EMI/RFI"? THE first rule of noise suppression is, Do It At The Source. Indeed, hindsight is golden, but Holy Fudd: with all the fun NASA has had with technology development as an innate part of system development (i.e., shuttle), this really should have been a no-brainer. ------------------------------ Date: Sat, 20 Mar 1993 17:21:52 GMT From: Gary Coffman Subject: will dust cool Venus? Newsgroups: sci.space In article <93078.145556GRV101@psuvm.psu.edu> Callec Dradja writes: >In my original article, I talked about several ideas regarding >the terraforming of Venus. I saw some responses to the problem >of the dense Venusian atmosphere but no one responded to my proposal >of using dust to cool Venus. Will this proposal of putting dust >in orbit around Venus in order to cool the planet work? I am afraid >that over time, the dust will heat up and begin radiating infrared >light which may slightly help warm Venus. I don't think, however, >that this effect would be significant. Should I assume that because >no one responded to the dust proposal, that everyone thinks that >it will work? I *suspect* without doing any math that the dust would be quickly swept away by light pressure and the solar wind. 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 | | ------------------------------ End of Space Digest Volume 16 : Issue 346 ------------------------------