Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from beak.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests) ID ; Mon, 23 Apr 90 01:57:58 -0400 (EDT) Message-ID: Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Mon, 23 Apr 90 01:57:26 -0400 (EDT) Subject: SPACE Digest V11 #305 SPACE Digest Volume 11 : Issue 305 Today's Topics: 890000 A ROBOTIC ASSISTANT FOR SPACE STATION FREEDOM re: Re SETI Re: Fermi paradox Re: Dyson spheres? Re: voyager images on cd Fwd: 890000 A ROBOTIC ASSISTANT FOR SPACE STATION FREEDOM Re: Aerobrake Vehicles I would like to join Re: Decompression and 2001 Re: Apollo 13, STS-1, Vostok 1 anniversaries Re: Fatal voltages ---------------------------------------------------------------------- Date: 21 Apr 90 01:45:49 GMT From: js7a+@andrew.cmu.edu (LIS USER JS7A) Subject: 890000 A ROBOTIC ASSISTANT FOR SPACE STATION FREEDOM IDNUM 03525372 TYPE Journal paper DATE 890000 AUTHOR McFalls, D.; Franke, E. TITLE A robotic assistant for Space Station Freedom SOURCE Robotics Today; vol.2, no.2; 1989; pp. 1-6 SUBJECT aerospace computer control; assembling; computerised materials handling; maintenance engineering; mobile robots; space vehicles; in-orbit construction; object retrieval; Extravehicular Activity Robotic Assistant; person retrieval; astronauts; robot language; Space Station; Freedom; prefabricated parts; highly autonomous free-flying robot; assembly; maintenance; EVA Retriever; EVAR; global positioning system Class codes: C3360L; C3390; C7460; C7420; C3320 CODEN ROTODJ ABSTRACT The Space Station Freedom is to be constructed in orbit from prefabricated parts. The article describes a highly autonomous free-flying robot the Extravehicular Activity (EVA) Robotic Assistant, designed to perform tasks including assembly, maintenance and retrieval of objects and people. The last of these objectives is considered especially. The EVA Retriever (EVAR) must locate an object, move to it, grasp it, and return it to where it should be. A language for the robots is discussed. The EVAR uses a global positioning system MISCELLANEOUS Treatment: practical Robot. Today (USA) Abstract number(s): C90006138 ISSN: 0193-6913 Refs: 8 END OF DOCUMENT ------------------------------ Date: Sun, 22 Apr 90 11:45:58 EST From: BROWN%CMR001.BITNET@vma.cc.cmu.edu Subject: re: Re SETI I have to agree with Steve Nuchia, don't rule anything out. A very good book which explores "an exotic combination" is Dragon's Egg by Robert L. Forward (ISBN 0-345-31666-5 for paperback). He also has a sequal called Starquake (which is even better). Basically Dragon's Egg/Starquake explore the idea of humans discovering life on a neutron star. CP6-Mail: Michael Brown @CMR NET-Mail: Michael Brown Snail-Mail: Service Informatique CMR, St-Jean, Que. J0J 1R0 ------------------------------ Date: 21 Apr 90 04:43:02 GMT From: zephyr.ens.tek.com!tektronix!percy!parsely!bucket!loop!keithl@uunet.uu.net (Keith Lofstrom) Subject: Re: Fermi paradox There is a stronger question implied by the Fermi paradox: If they are out there, and even if they have rules preventing local visits, why don't we see their infrared emissions? Why are there so many high-quality energy sources (visible stars) compared to heat sources? Surely an advanced civilization would be using most of the energy from their local stars, perhaps even dismantling them. Unless there's an efficient way to dump waste heat into a black hole, this would make for some pretty spectacular infrared sources! ---- To add to all the other more plausible explanations, one possibility is that "they" have access to much higher quality resources than we see or know about, and we are living in the cosmic trash heap! Perhaps by the time a civilization in this galaxy learns interstellar travel, they find out there are much better places to live, and go elsewhere... -- Keith Lofstrom keithl@loop tektronix!psueea!qiclab!loop!keithl Launch Loop, P.O. Box 1538, Portland, Oregon 97207 (503)-628-3645 ------------------------------ Date: 22 Apr 90 22:01:56 GMT From: deimos.cis.ksu.edu!iowasp!dyson@uunet.uu.net Subject: Re: Dyson spheres? In article <10461@sun.udel.edu>, salamon@sun.udel.edu (Andrew Salamon) writes: > So whats a dyson sphere? > > Magic in my Mind | /Andrew/ > Music in my Heart | soi-disant Bleydion op Rhys > Laughter in my Soul | salamon@sun.acs.udel.edu > And...A Sword in my Fist (sigh) | A "Dyson Sphere" is the name associated with a concept that Freeman Dyson (a VERY eminent professor of Physics at Princeton University) suggested some time ago dealing with the product of a very advanced civilization. Dyson suggested that at some point in the advancement of some civilizations, they would develop the ability to transform all of the matter of their solar system into a very thin layered hollow sphere centered on their star. In this way they could fully utilize the total stellar energy output as well as the maximum surface area on the interior of the sphere. Dyson recognized that an Earth-based observer would see a very bright infared source with no visible component. This concept was used by Larry Niven (in an economy mode!:)) in the creation of his "RINGWORLD". I highly recommend this story and the sequel "RINGWORLD ENGINEERS". Just in case you're interested, I am not related to him. Just a coincidence! Every physics prof I've ever had asked the same question on the first day of class. The penguin -- Richard L. Dyson Department of Physics & Astronomy Graduate Research Assistant University of Iowa INTERNET: (1st choice) Dyson@Iowasp.Physics.UIowa.EDU INTERNET: (2nd choice) RDyson@Primea.Weeg.UIowa.EDU SPAN DECnet: IOWASP::DYSON Home: (319) 338--6117 Office: (319) 335--1864 ------------------------------ Date: 22 Apr 90 23:07:30 GMT From: portal!cup.portal.com!Chris_F_Chiesa@apple.com Subject: Re: voyager images on cd Hmm, I came in on the middle of this conversation, but I'm fascinated by the idea of obtaining Voyager imagery on CD! What can anyone tell me about this? How do I get 'em? What do I need, EXACTLY, to read 'em? (I.e., are there some CD drives that will, and other drives that won't, read them? What file structure on the CD itself?) What is the data format of the images themselves? My company is about to obtain some form of CD drive; how would I determine whether the one we get would be able to read the images being discussed here? Once I can get a drive to read 'em, and know what the image for- mat is on them, I can write software to convert 'em to what I can view... Thanks in advance for any info; if you post here, please e-mail too, as I find myself unable to keep up with the volume of this newgroup, try as I might! Thanks! Chris Chiesa Software Engineer Light Valve Technology - A Kodak Company Chris_F_Chiesa@cup.portal.com ------------------------------ Date: 21 Apr 90 21:18:05 GMT From: js7a+@andrew.cmu.edu (James Price Salsman) Subject: Fwd: 890000 A ROBOTIC ASSISTANT FOR SPACE STATION FREEDOM I thought this newsgroup might be interested in this reference. IDNUM 03525372 TYPE Journal paper DATE 890000 AUTHOR McFalls, D.; Franke, E. TITLE A robotic assistant for Space Station Freedom SOURCE Robotics Today; vol.2, no.2; 1989; pp. 1-6 SUBJECT aerospace computer control; assembling; computerised materials handling; maintenance engineering; mobile robots; space vehicles; in-orbit construction; object retrieval; Extravehicular Activity Robotic Assistant; person retrieval; astronauts; robot language; Space Station; Freedom; prefabricated parts; highly autonomous free-flying robot; assembly; maintenance; EVA Retriever; EVAR; global positioning system Class codes: C3360L; C3390; C7460; C7420; C3320 CODEN ROTODJ ABSTRACT The Space Station Freedom is to be constructed in orbit from prefabricated parts. The article describes a highly autonomous free-flying robot the Extravehicular Activity (EVA) Robotic Assistant, designed to perform tasks including assembly, maintenance and retrieval of objects and people. The last of these objectives is considered especially. The EVA Retriever (EVAR) must locate an object, move to it, grasp it, and return it to where it should be. A language for the robots is discussed. The EVAR uses a global positioning system MISCELLANEOUS Treatment: practical Robot. Today (USA) Abstract number(s): C90006138 ISSN: 0193-6913 Refs: 8 :James ------------------------------ Date: 22 Apr 90 18:20:12 GMT From: shelby!portia!gooch@decwrl.dec.com (Carl Gooch) Subject: Re: Aerobrake Vehicles In article <6051@ccncsu.ColoState.EDU> jn190068@longs.LANCE.ColoState.EDU (Jay Lewis Nestle) writes: >I am interested in doing possible graduate work on aerobrake >and reentry vehicle design, test, and simulation. > Has anyone done any reentry vehicle modelling or analysis in wind >tunnels of this type? If so which design criteria (i.e. Reynolds, >Froude, etc.) did you use and why? I haven't actually done any design work in this area, but I've taking more than enough aerothermodynamics courses to know that Mach and Reynolds numbers, while important for re-entry simulations and experiments, are not necessarily the most important. At re-entry speeds (and this goes at least double for Earth- Mars or Mars-Earth trajectories), the heating behind a shock wave causes air to react. Your average reacting air model includes quite a few chemical species: N2, O2, NO, N, O, N+, O+, NO+, e-, and maybe some tri-atomic species too. There will be maybe as many as 40 or 50 chemical reactions to calculate. That's for the Earth's atmosphere. For Mars you start with basically an N2/CO2 atmosphere and the chemistry is worse; CO2 reacts to form the most astounding things! All of this chemistry nonsense is not intrinsically difficult to program, although it's tedious; the big problem is that at very high temperatures the reaction rates are questionable. Other factors which are neglected: Radiation is (at least almost) universally calculated as an afterthought, which is okay for moderate temps, but not for 25 km/sec re-entry. The flow is always treated as weakly ionized because of the huge problems which otherwise inevitably occur in you chemistry model. So, having said all of those encouraging words about state-of-the-art simulations, what about experiments? Well, the three most important non-dimen- sional parameters are Mach, Reynolds, and Damkoehler numbers. (Damkoehler # is a ratio of characteristic flow time to characteristic chemical reaction time.) Getting all three of these to match in an experimental facility is next to impossible. Shock tunnels can get Damkoehler number right, and Reynolds number is just a matter of model scaling, but to get high enough Mach numbers you have to expand the flow so much that the freestream conditions are way off chemically. A ballistic range (boo! hiss! shout the wind tunnel people) can get everything except Damkoehler number, which is a bitch to match in a ballistic range because of the small size of the models. I guess the short answer to your question is that lots of people are working on this problem, but that there are strict limitations on the accuracy of their results which are completely unrelated to the accuracy of their coding/experi -mental technique. >Also if there is any information out there concerning other schools or >companies that do this sort of research work please let me know. Thanks in >advance! Jay. May I, as a humble grad student, humbly mention that Stanford Aero/Astro and ME departments, in conjunction with NASA-Ames and their All-Cray Orchestra are doing lots and lots of things in this area. We play with numerical models and solution techniques on the one hand and some great experimental toys on the other. No ballistic range at the moment, alas. (The last sentence is brought to you by Acme Asbestos Keyboards and Monitors, Inc.) If you have any questions about your project or about grad school, Jay, send me e-mail and I'll see what I can do to help. -- Carl Gooch gooch@portia.stanford.edu Disclaimer: You think Stanford actually agrees with this? Hah! If they want my opinions and theirs to match they should pay me enough to agree with them! ------------------------------ Date: Sun, 22 Apr 90 22:42 CST From: The Angry Young Man Subject: I would like to join I would like to join this mailing list if possible. Thanks, Juan Cabanela CABANELJ@CARLETON.EDU ------------------------------ Date: 22 Apr 90 17:44:54 GMT From: psuvm!mrw104@psuvax1.cs.psu.edu Subject: Re: Decompression and 2001 In article <2302@wrgate.WR.TEK.COM>, dant@mrloog.WR.TEK.COM (Dan Tilque) says: >By a not so amazing coincidence, this was also a Clarke story. It was >written back in the 50's, I think. Unfortunately, I can't remember the >name but the plot goes like this: > The Clarke story in question was "Take a Deep Breath," and I don't know about you guys, but I wouldn't try holding my breath in hard vacuum; I'd be afraid of breaking my jaw, and then losing the air anyway. I might try sticking my fingers in my ears, though. Mike Williams mrw104@psuvm.edu ------------------------------ Date: 22 Apr 90 04:19:22 GMT From: hpfcso!hpfinote!ddj@hplabs.hp.com (Doug Josephson) Subject: Re: Apollo 13, STS-1, Vostok 1 anniversaries In article <89@newave.UUCP> john@newave.mn.org (John A. Weeks III) writes: >Duct Tape? Why on earth did they have duct tape on the Apollo? ^^^^^^^^ (hmmm, 'off earth' maybe? :^) ) >How much did this flight certified duct tape cost? Did any of the >LM's that landed on the moon carry duct tape? Well, at least the Apollo 15 LM carried duct tape to the moon. From "To Rule The Night" by James Irwin (LMP on Apollo 15): "We had rolls of the tape; we'd strip it off to make a kind of sticky fielder's glove, and we'd use it to mend or reinforce things that were damaged or broken. In this new, curious, weightless world, it was a surface that you could count on to hold things." And later in the book, when Irwin is inspecting his backpack prior to a lunar EVA: "When I examined mine, I found a large-sized nick in the antenna. We reported it and ended up using that good gray tape to wrap and reinforce it at the weak point so that it wouldn't break off." It'd be interesting when somebody gets back to the Apollo 15 site to see if that stuff is still sticky after exposure to the Moon's tropical climate for years. My money's on the tape! LET'S SPRAY SOME RUSTOLEUM ON A HORIZONTAL SATURN V AND GO SEE!!!! ( Sorry - I think the altitude is affecting my brain today! %^) ) Doug Josephson ddj@hpfinote.HP.COM Fort Collins, CO (4980' ASL, only 250000 more miles of elevation gain to go...) ------------------------------ Date: 23 Apr 90 00:23:33 GMT From: cs.utexas.edu!texbell!nuchat!steve@tut.cis.ohio-state.edu (Steve Nuchia) Subject: Re: Fatal voltages In article <90112.160126GILLA@QUCDN.BITNET> GILLA@QUCDN.QueensU.CA (Arnold G. Gill) writes: >>the saddle in the 50% fatal voltage level curve, 50 Hz is closer. > You are going to have to explain this one to me a little bit better. I No problem. I'm working from memory though. >guess I was always under the mistaken impression that the dangers of >electricity have a lot more to do with voltage and the amount of current that >that voltage can pump through a person The critical value, at low power level, is the current through the heart. At high power levels it just cooks flesh, and you may die of shock even if the current path doesn't involve the nervous system. Shocks not involving the heart can also cause convulsions, which may be dangerous in their own right. > (0.1A is supposedly the fatal current level) A tenth of that through the torso will usually be fatal, less sometimes is. Your skin has a DC resistance in the megohms when dry, but it is rather thin. Once inside the bulk resistance varies depending on the tissue involved, but is rather low. The skin resistance can be broken down by puncture, charring, capacitive coupling, or just by having enough voltage. > What effect can frequency have? Frequency has an effect on how well the energy is coupled to you and how much current is associated with your capacitance relative to ground. At very high frequencies the skin effect (referring to the outer portion of a conductor, not people-skin) causes most of the current to flow near the surface of the body, avoiding the heart. Neither of these effects is significant in the 10-400 Hz region. In that region the important effect seems to be the match between the frequency of the shock and the natural frequencies of the heart heart's control "circuits". It is a second-order effect, and the curve I alluded to is rather shallow, and it moves around depending on individual factors, but it is statistially significant. If anybody happens to know of a good reference I'd appreciate a pointer too. ------------------------------ End of SPACE Digest V11 #305 *******************