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 ; Fri, 4 May 90 02:28:21 -0400 (EDT) Message-ID: Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Fri, 4 May 90 02:27:17 -0400 (EDT) Subject: SPACE Digest V11 #353 SPACE Digest Volume 11 : Issue 353 Today's Topics: Re: Fatal voltages Re: Galileo entry probe Hubble Space Telescope Update - 05/04/90 Re: * SpaceNews 30-Apr-90 * Status of Projects... mail problem Re: Manned mission to Venus Heroes come in all sizes! ---------------------------------------------------------------------- Date: 30 Apr 90 16:31:31 GMT From: mcsun!ukc!stl!stc!root44!hrc63!mrcu!paj@uunet.uu.net (Paul Johnson) 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 >>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... The following is abstracted from an Safety Guidance Note on the Safe Use of Electricty in my company. Any errors, spelling mistakes etc are mine, and the following does not necessarily represent company policy or opinion. When an electric current passes through the body, muscles are stimulated and may react in one of two ways:- 1) A violent reaction in which leg or arm straightens and throws the person across the room. 2) Muscles may contract and become rigid, itghtening the grip and reducing contact resistance. If chest muscles or nervous system is involved, breathing can be stopped and the heart affected. In a series of experiments, 150 male volunteers had various currents passed from hand to hand. Below 1 mA, 50Hz A.C., the current is virtually undetectable. Above this level pain increases to be very unpleasant at 9 mA. Most healthy men can let go at this point, but none could release above 24 mA. At 20mA or greater, lung muscles contract and breathing stops, although it may restart naturally if the current is stopped quickly. By this stage there is also great pain with burns. Experiments with animals from guinea-pigs to cows have revealed a linear relationship between weight and current required to cause ventricular fibrillation. There was also a relationship between the time between current (I, milliAmps) and time (T, Seconds). Assuming a body weight of 50 kg (8 stone) this is I = 116/sqrt(T) In other words, 50mA for 5 seconds would probably cause fibrillation. It was easier to cause fibrillation than to stop the heart completely. (Note: a fibrillating heart is harder to restart than a completely stopped one: the fibrillation must be stopped and the heart then restarted.) With frequencies either side of 50 Hz there is a marginal imprevement in the let-go current. With DC, muscular control is not lost so that the victim has a better chance of escape, althought the greatest pain is experienced when breaking the circuit. The resistance of the human body varies considerably. A good contact with bare skin, hand to hand or hand to foot gives about 2500 ohms at 25 volts, reducing to 1000 ohms at 250 volts with a minimum asymptotic value of 650 ohms. This suggests that a maximum safe voltage is only 35 volts, although of course contacts are usually glancing rather than full grip, and shoes and clothing increase safety considerably. Never the less, potential danger is present. Reference: M.P. Smith: Electrocuiton, Its Effects and Prevention. J. Naval Science, Vol 3, No 1, Jan 1977, P39-44. -- Paul Johnson UUCP: !mcvax!ukc!gec-mrc!paj --------------------------------!-------------------------|------------------- GEC-Marconi Research is not | Telex: 995016 GECRES G | Tel: +44 245 73331 responsible for my opinions. | Inet: paj@uk.co.gec-mrc | Fax: +44 245 75244 ------------------------------ Date: 3 May 90 16:04:16 GMT From: usc!elroy.jpl.nasa.gov!jato!mars!baalke@ucsd.edu (Ron Baalke) Subject: Re: Galileo entry probe In article <1990Apr30.161227.14460@axion.bt.co.uk> apengell@axion.bt.co.uk (alan pengelly) writes: > > Does the Galileo probe that is going to enter the Jovian atmosphere >have a camera on board? What other sensors are present? No, the Galileo probe does not carry a camera. The probe does have the following six instruments: Atmospheric Structure Instrument - Determines temperature, pressure, density, and molecular weight as a function of altitude. Neutral Mass Spectrometer - Determines chemical composition of the atmosphere. Helium Abundance Detector - Determines relative abundance of helium. Nephelometer - Detects clouds and infer states of particles. Net Flux Radiometer - Determines ambient thermal and solar energy as a function of altitude. Lightning and Energetic Particles - Verifies the existence of lightning and measures energetic particles in the inner magnetosphere. Ron Baalke | baalke@mars.jpl.nasa.gov Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov 4800 Oak Grove Dr. | Pasadena, CA 91109 | Go Lakers! ------------------------------ Date: 4 May 90 00:15:16 GMT From: sdd.hp.com!zaphod.mps.ohio-state.edu!usc!elroy.jpl.nasa.gov!jato!mars.jpl.nasa.gov!baalke@ucsd.edu (Ron Baalke) Subject: Hubble Space Telescope Update - 05/04/90 HUBBLE SPACE TELESCOPE MAY 4, 1990 Hubble Space Telescope Operators completed dumping the full contents of all three spacecraft engineering and science tape recorders yesterday for analysis. The downlink includes recorded data on the first safemode entry last week. Yesterday morning, the Hubble team prepared to execute an 18-hour series of tests to evaluate a fine guidance sensor pattern match variance. The pattern match compares pinpoints of starlight with predicted data and evaluates pointing system performance. An earlier test of the sensors indicated a slight oscillation of the telescope's roll axis. The test was hampered by communication dropouts, but operators hope to complete the pattern match test when the data is retrieved during the next tape recorder dump. Ron Baalke | baalke@mars.jpl.nasa.gov Jet Propulsion Lab M/S 301-355 | baalke@jems.jpl.nasa.gov 4800 Oak Grove Dr. | Pasadena, CA 91109 | Go Lakers! ------------------------------ Date: 3 May 90 06:06:34 GMT From: zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!ucselx.sdsu.edu!sdsu!crash!skipsand@tut.cis.ohio-state.edu (Skip Sanders) Subject: Re: * SpaceNews 30-Apr-90 * The shuttle astronaut INTERCOM headsets ALSO transmit on 279.0 (except during military flights, when they use IR links instead) and have been heard before during flight by listeners on the ground. That is likely what was heard this time, as the astronauts did not exit the airlock, and I'd not expect the suit transmitters to get out of the sealed air lock very well at all... ------------------------------ Date: 3 May 90 16:34:49 GMT From: sdd.hp.com!samsung!rex!rouge!dlbres10@ucsd.edu (Fraering Philip) Subject: Status of Projects... Does anyone have any information on the status of the following projects: 1. Nasa's Shuttle-2 2. MMI's Space Van 3. Advanced Launch System 4. SSX 5. Phoenix 6. Anything else that would launch to space cheaply. Thanks in advance, Philip Fraering ------------------------------ Date: Wed, 28 Feb 90 14:38:51 PST From: mordor!lll-tis!ames!ucsd!trout.nosc.mil!crash!pnet01!crash!crash_mailer_daemon@angband.s1.gov To: pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!nosc!relay. Subject: mail problem Trouble sending mail on `crash', Wed Feb 28 13:37:18 1990 ============ Transcript follows ============ 1!pro-abyss!pro-harvest!warlock 0 alias errors bad system name: 1 uux failed ( 11 ) mail.local.r: pipe to uux: write error mail.local.r: uux execution error Can't send to: 1!pro-abyss!pro-harvest!warlock 1 delivery errors 1 total errors ============== Message follows ============= >From pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!pnet01!crash!nosc!relay.EU.net!quando!henigan Wed Feb 28 13:37:18 1990 remote from crash Received: by crash.cts.com (smail2.5) id AA01502; 28 Feb 90 13:37:18 PST (Wed) remote from crash om crash Received: by crash.cts.com (smail2.5) id AA00944; 28 Feb 90 12:36:17 PST (Wed) remote from crash om crash Received: by crash.cts.com (smail2.5) id AA00622; 28 Feb 90 11:42:11 PST (Wed) remote from crash om crash Received: by crash.cts.com (smail2.5) id AA29991; 28 Feb 90 10:36:38 PST (Wed) remote from crash om crash Received: by crash.cts.com (smail2.5) id AA29370; 28 Feb 90 09:37:43 PST (Wed) remote from crash om crash Received: by crash.cts.com (smail2.5) id AA28634; 28 Feb 90 08:42:31 PST (Wed) remote from crash om crash Received: by crash.cts.com (smail2.5) id AA27801; 28 Feb 90 07:17:00 PST (Wed) remote from crash om crash Received: by crash.cts.com (smail2.5) id AA26667; 28 Feb 90 05:56:33 PST (Wed) remote from crash om crash Received: by crash.cts.com (smail2.5) id AA26212; 28 Feb 90 05:16:46 PST (Wed) Received: by crash.cts.com (smail2.5) id AA24787; 28 Feb 90 04:17:11 PST (Wed) Received: by crash.cts.com (smail2.5) id AA24593; 28 Feb 90 03:57:03 PST (Wed) Received: by crash.cts.com (smail2.5) id AA24437; 28 Feb 90 03:37:18 PST (Wed) Received: by crash.cts.com (smail2.5) id AA24226; 28 Feb 90 03:16:47 PST (Wed) Received: by crash.cts.com (smail2.5) id AA23895; 28 Feb 90 02:56:42 PST (Wed) Received: by crash.cts.com (smail2.5) id AA23378; 28 Feb 90 02:36:14 PST (Wed) Received: by crash.cts.com (smail2.5) id AA23233; 28 Feb 90 02:16:41 PST (Wed) Received: by crash.cts.com (smail2.5) id AA22832; 28 Feb 90 01:58:51 PST (Wed) Received: by crash.cts.com (smail2.5) id AA22505; 28 Feb 90 01:36:19 PST (Wed) Received: by crash.cts.com (smail2.5) id AA22142; 28 Feb 90 01:20:17 PST (Wed) Received: by crash.cts.com (smail2.5) id AA21850; 28 Feb 90 00:56:20 PST (Wed) Received: by crash.cts.com (smail2.5) id AA21549; 28 Feb 90 00:36:18 PST (Wed) Received: by crash.cts.com (smail2.5) id AA21366; 28 Feb 90 00:12:13 PST (Wed) Received: by crash.cts.com (smail2.5) id AA20646; 27 Feb 90 23:37:59 PST (Tue) Received: from mcsun.eu.net by trout.nosc.mil (5.59/1.27) id AA16049; Tue, 27 Feb 90 23:35:27 PST Received: by mcsun.EU.net with SMTP; Wed, 28 Feb 90 08:35:10 +0100 (MET) Received: from quando.uucp by unido.informatik.uni-dortmund.de with uucp via EUnet (UNIDO-2.0.0.c) for mcsun.eu.net id AI24550; Wed, 28 Feb 90 08:27:26 +0100 From: henigan@quando.quantum.de (Kevin Henigan) Message-Id: <9002280707.AA12750@quando.quantum.de> Received: by quando.quantum.de; Wed, 28 Feb 90 08:07:47 +0100 Subject: Re: Titan Software. To: warlock@pro-harvest.cts.com (Jamie Coe) Date: Wed, 28 Feb 90 8:07:47 MET DST In-Reply-To: <9002211217.AA07351@hp-sdd.sdd.hp.com>; from "Jamie Coe" at Feb 20, 90 11:34 pm X-Mailer: ELM [version 2.2 PL14] > Well.... it worked... sort of... the file had a bad CRC when I tried >to de SciiBin it. So somewhere in the mail system a character or to got >tweaked. However... I did get enough of the file to know that it will >unconvert alright if the data is not corrupted in transfer. Could you try one >more time please? > Jamie de Warlock@Pro-Harvest Sorry to hear that, OK, I will send the again, they are on their way... -- Kevin Henigan. UUCP: {backbone}!unido!quando!henigan OR henigan@quando.uucp Quantum GmbH Bitnet: UNIDO!quando!henigan OR henigan%quando@UNIDO(.bitnet) Dortmund internet: henigan%quando%unido.UUCP@mcsun.cwi.nl Germany internet: henigan@quando.quantum.de ------------------------------ Date: 4 May 90 04:42:52 GMT From: usc!cs.utexas.edu!news-server.csri.toronto.edu!qucdn!gilla@ucsd.edu (Arnold G. Gill) Subject: Re: Manned mission to Venus In article <3332@calvin.cs.mcgill.ca>, msdos@quiche.cs.mcgill.ca (Mark SOKOLOWSKI) says: > >I would like to start a new discussion about a manned mission to Venus. > >And for those that doubt about my seriousness, I am glad to tell that I >will be the first to volunteer to go there... After all our technology >can enable us to make life bearable even at 900 F and 90 athmospheres I expected a smiley there. After all, our wonderful technology can survive on Venus for all of two hours - at best. The average is close to half an hour. By the way, what exactly is Fahrenheit? :-) ------- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- | Arnold Gill | | | Queen's University at Kingston | If I hadn't wanted it heard, | | BITNET : gilla@qucdn | I wouldn't have said it. | | X-400 : Arnold.Gill@QueensU.CA | | | INTERNET : gilla@qucdn.queensu.ca | | -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- ------------------------------ Date: 3 May 90 15:19:44 GMT From: mcsun!ukc!edcastle!aipp@uunet.uu.net (Pavlos Papageorgiou) Subject: Heroes come in all sizes! Greetings to the Net and many thanks to Henry Spencer for his informative reply on my question on orbital debris some time ago. Now, here's my next devious question: How does NASA, or any other space-faring organisation for that matter, approach the issue of physical size and weight of their astronauts? Size and weight measures for 'average' people typically lie in a range about a factor of 2. The large and heavy person may then be about 45Kg heavier than the small one, which is hardly a great problem in itself; they will, however, consume correspondingly greater amounts of food, water and air, and produce more waste, which will mandate a larger (and heavier) life support system, a more important consideration. Most importantly, a bigger person would require a much larger habitable volume, in addition to bigger fittings, passages etc, which could mean tons of additional structural weight. Is this a factor influencing the recruitment of astronauts? Traditionally, astronauts were selected from the air force and it seems that the military would welcome large people because of their strength, but for a space mission this is irrelevant and a tiny person would perform just as well. It may well be that small people are also more durable against hi-G's and general hardship, and the same is probably true for women, who tend to be of more 'economical' sizes in general. George Bush could also enjoy towering over them in PR photos :-) Pavlos Papageorgiou ================================================================================ "Do you think, that they will think, his arm is permanently attached in this position" --- Laurie Anderson (about the picture on the golden disc aboard the Voyagers) ------------------------------ End of SPACE Digest V11 #353 *******************