Date: Wed, 10 Mar 93 05:06:44 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V16 #298 To: Space Digest Readers Precedence: bulk Space Digest Wed, 10 Mar 93 Volume 16 : Issue 298 Today's Topics: 20 kHz Power Supplies "blowing up"! Acceleration of ice Anyone interested in being a consultant (read) latest manifest Lunar Ice Transport Minimal Manned Capsule paper online now... (2 msgs) Mir visible UK/Ireland PFF Instruments Proposed Jupiter f/c/b mission (3 msgs) Rocket Propulsion (3 msgs) Starprobe Will Huygens Float 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: 9 Mar 1993 23:23 CST From: wingo%cspara.decnet@Fedex.Msfc.Nasa.Gov Subject: 20 kHz Power Supplies "blowing up"! Newsgroups: sci.space In article <1niun0INNi6t@access.digex.com>, prb@access.digex.com (Pat) writes... >In article <9MAR199308521171@tm0006.lerc.nasa.gov> dbm0000@tm0006.lerc.nasa.gov (David B. Mckissock) writes: >>In article <1ng5a0INN1lp@access.digex.com>, prb@access.digex [various rantings deleted] >Basic engineering criteria and design decisions were made for SSF >on fatally flawed reasoning. all the paper in the world won't >make up for those mistakes. > >I dare you to justify 3 things: > > 1) 20 KHz power developement. > Since I started this and you have jumped on it like a bulldog I will answer you. The primary advantage of 20 khz is light weight and some ease of integration of the entire system in orbit. It has several disadvantages that were conclusively shown in 1988 and 1989. There never was a lot of money spent on the idea. It was a brainchild of the Lewis folks who were given the task of coming up with the requirements for WP IV. Since Marshall already had a power system in place that was a 75KVA demonstrator based upon an incremental upgrade of Skylab, the boys at Lewis simply wanted to explore if technologically, there was a better solution. It turns out that there was no better method and still today that is true. The issue was settled years ago and nothing bad came of it. You are the one pat that is always pushing technology, but when someone does that then you get upset. And don't say that anyone that has common sense could see that 20khz would not work. It was a good idea to try even if it did lead to a dead end. > 2) Non Metric (english) component selection with the > european modules being Metric. > So what. Read a Japanese technical manual. They quote everything in metric but if you do the conversions they are english standard. Who cares if the english system takes a little math to do the work. Metric is good but we have had the technology for conversions for a hundred years now and it is well understood. > 3) Total failure to practice EVA until this year. > I guess you never saw many missions before Challenger. They blew it by going off the other end and being too conservative. Well with the Intelsat rescue that changed so what is your problem? Me thinks you like to complain too much Dennis University of Alabama in Huntsville ------------------------------ Date: Wed, 10 Mar 1993 06:56:31 GMT From: David Bromage Subject: Acceleration of ice Newsgroups: sci.chem,sci.engr.chem,sci.space,sci.physics Daniel Seeman (dseeman@novell.com) wrote: >Hi, >I have no answers, but a comment. Aren't there ice crystals in the trailing >stream of a commet? I don't know how fast they are traveling, or if they >just appear in the trailing stream because of some condensation process (I >doubt it, though). But you may want to research this for some additional >insights... The tail of a comet is quite a complex mixture of gases. A comet is made mostly of ice, with a bit of methane, ammonia and carbon monoxide and a bit of dust and rock. As early as 1868 the astronomer William Huggins found common features between the spectrum of a comet's tail and natural gas ("olefiant' gas). He also identified organic matter in comets and later cyanogen was found. What you see as the tail is a stream of gases being released from the comet as it is warmed by the solar wind. The tail does not flow in the opposite direction to the comet's motion but points away from the sun. It is also possible that the gases may glow as an aurora does, but I'm not 100% sure of that. If anyone can add to this, please do. David Bromage ------------------------------ Date: Wed, 10 Mar 1993 03:39:27 GMT From: terence robert slywka Subject: Anyone interested in being a consultant (read) Newsgroups: sci.space,sci.optics,sci.electronics,sci.aeronautics Do you have a skill or specialized knowledge to offer the marketplace? Are you interested in short-term projects that demand your specific skill? Are you interested in evening/weekend work-at-home for local, national and international companies while keeping your present job? If you answer 'yes' to any or all of these questions you can not afford to miss this opportunity. If you are interested in working for large and small businesses as a consultant contact me directly at the addresses listed below and I will send you additional information by regular mail. TSLYWKA@IUBACS TSLYWKA@UCS.INDIANA.EDU Respectfully, Terence Slywka ------------------------------ Date: 10 Mar 93 06:29:00 GMT From: apryan@vax1.tcd.ie Subject: latest manifest Newsgroups: sci.space Can someone email me the very latest shuttle manifest please? -Tony Ryan, "Astronomy & Space", new International magazine, available from: Astronomy International, P.O.Box 2888, Dublin 1, Ireland. 6 issues (one year sub.): UK 10.00 pounds, US$20.00 (surface, add US$8.00). ACCESS/VISA/MASTERCARD accepted (give number, expiry date, name&address). Newslines (48p/36p per min): 0891-88-1950 (UK/NI) 1550-111-442 (Eire). ------------------------------ Date: Wed, 10 Mar 1993 04:46:25 GMT From: Henry Spencer Subject: Lunar Ice Transport Newsgroups: sci.space In article <1993Mar9.200156.2749@sol.UVic.CA> rborden@uglx.UVic.CA (Ross Borden) writes: > To maintain high through-put, a continuous stream of vehicles >would haul ice from the polar ice mines to the equatorial processing >plants... Surely it's a whole lot simpler to put the processing plants at the poles too. (For one thing, at the poles all they need is a tall tower to get continuous solar power.) >And are there lunar maps with sufficient resolutions to chart a route? The lunar map situation is, roughly speaking, incredibly poor. We have much better maps of Mars than of the Moon. The situation should improve substantially with the Clementine 1 mission next year. -- C++ is the best example of second-system| Henry Spencer @ U of Toronto Zoology effect since OS/360. | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 10 Mar 1993 06:36:52 GMT From: George William Herbert Subject: Minimal Manned Capsule paper online now... Newsgroups: sci.space After several requests, I've put an ASCII format version of my 1991 paper on Minimal Manned Capsules and the current 1993 commentary on it (including where I went wrong to start and the changes to the vehicle concept since 1991). They're available at the ftp site ocf.berkeley.edu login anonymous directory pub/Space files mmc.91paper and mmc.91commentary They may be uploaded to the International Space Universoty FTP server (info.isunet.edu) at some point, though that is waiting on my doing some other projects at ISU. Please keep in mind that I was still an undergrad student at the time the inital paper was written, and in some ways it shows it (in addition to just the major technical problem of having underestimated heatshield mass the first time). It's a professional paper, but not a matured professional paper 8-) -george william herbert Retro Aerospace gwh@soda.berkeley.edu gwh@ocf.berkeley.edu gwh@retro.com ------------------------------ Date: 10 Mar 93 06:36:10 GMT From: George William Herbert Subject: Minimal Manned Capsule paper online now... Newsgroups: sci.space After several requests, I've put an ASCII format version of my 1991 paper on Minimal Manned Capsules and the current 1993 commentary on it (including where I went wrong to start and the changes to the vehicle concept since 1991). They're available at the ftp site ocf.berkeley.edu login anonymous directory pub/Space files mmc.91paper and mmc.91commentary They may be uploaded to the International Space Universoty FTP server (info.isunet.edu) at some point, though that is waiting on my doing some other projects at ISU. Please keep in mind that I was still an undergrad student at the time the inital paper was written, and in some ways it shows it (in addition to just the major technical problem of having underestimated heatshield mass the first time). It's a professional paper, but not a matured professional paper 8-) -george william herbert Retro Aerospace gwh@soda.berkeley.edu gwh@ocf.berkeley.edu gwh@retro.com ------------------------------ Date: Wed, 10 Mar 1993 06:41:08 GMT From: apryan@vax1.tcd.ie Subject: Mir visible UK/Ireland Newsgroups: sci.space,sci.astro If anyone in UK/Ireland watches out for Mir please post your latitude, longitude, height above sea-level and UT when you see Mir pass above or below any convenient bright star. You can get latest prediction of when to look from newslines below: -Tony Ryan, "Astronomy & Space", new International magazine, available from: Astronomy International, P.O.Box 2888, Dublin 1, Ireland. 6 issues (one year sub.): UK 10.00 pounds, US$20.00 (surface, add US$8.00). ACCESS/VISA/MASTERCARD accepted (give number, expiry date, name&address). Newslines (48p/36p per min): 0891-88-1950 (UK/NI) 1550-111-442 (Eire). ------------------------------ Date: Wed, 10 Mar 1993 03:36:04 GMT From: Dave Tholen Subject: PFF Instruments Newsgroups: sci.space Steve Derry writes: > Since there will be two PFF spacecraft, would it make sense for the two to > carry slightly different science payloads? For example, the second spacecraft > could carry a magnetometer in place of the UV spectrometer. > > This would allow a broader science return while remaining within mass and > power constraints (although program costs and risk would increase slightly). It's been discussed, but as you can imagine, different payloads mean different designs, which all translates into higher costs. This is not meant to say that it won't be done. If it can be done within the cost constraints, and if it is determined to be sufficiently valuable, then I suspect that the OPSWG will endorse the idea. ------------------------------ Date: 10 Mar 1993 02:26:41 GMT From: James Ashton Subject: Proposed Jupiter f/c/b mission Newsgroups: sci.space In article <9MAR199321020689@kelvin.jpl.nasa.gov>, baalke@kelvin.jpl.nasa.gov (Ron Baalke) writes: > In article , henry@zoo.toronto.edu (Henry Spencer) writes... > >In article pgf@srl01.cacs.usl.edu ("Phil G. Fraering") writes: > >>Earth-moon or earth-sun lagrange point? > >> > >>It looks like you're talking about the earth-sun L1 point, but > >>isn't that a little far? > > > >Sounded to me like Earth-Sun, and it's only about 1.5 million km away. > >A halo orbit around the Earth-Sun L1 is a good place to park something > >that wants to be well away from Earth and in continuous sunlight. > > That is exactly where the Soho spacecraft will be placed, in halo orbit > around the Earth-Sun L1 point. It is due to be launched in 1995. What do you mean by a halo orbit? I'm aware that trojan asteroids orbit L4 and L5 points but my understanding was that no other L points were stable. I thought that there was a (small) gravity well around L4 and L5 but that L1, L2 and L3 all had gravity humps (or maybe saddle points) so that you'd need to be exactly on the point to avoid disturbing forces. -- James Ashton System Administrator VK2ZJA Department of Systems Engineering Voice +61 6 249 0681 Research School of Physical Sciences and Engineering FAX +61 6 249 2698 Australian National University Email James.Ashton@anu.edu.au Canberra ACT 0200 Australia ------------------------------ Date: Wed, 10 Mar 1993 04:50:40 GMT From: Henry Spencer Subject: Proposed Jupiter f/c/b mission Newsgroups: sci.space In article <1993Mar9.191721.1@stsci.edu> gawne@stsci.edu writes: >RB| That is exactly where the Soho spacecraft will be placed, in halo orbit >RB| around the Earth-Sun L1 point... > >I *think* that the L1 "point" is large enough for several spacecraft to >stay there at a time. It _is_ one of the astable Lagrange points, so >stationkeeping will be necessary to hold it there lest it drift off. At the L1 point itself you might worry a bit about collisions, although it's still pretty unlikely. However, these craft will be in halo orbit around the L1 point, not at the point itself. Putting them 180 degrees away from each other in the halo orbit will suffice to keep them hundreds of thousands of km apart. -- C++ is the best example of second-system| Henry Spencer @ U of Toronto Zoology effect since OS/360. | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Wed, 10 Mar 1993 04:56:29 GMT From: Henry Spencer Subject: Proposed Jupiter f/c/b mission Newsgroups: sci.space In article <1njjl1INN8ca@manuel.anu.edu.au> jaa101@gorton.anu.edu.au (James Ashton) writes: >What do you mean by a halo orbit? ... The L1 point is on the Earth-Sun axis. It's not terribly stable. But an "orbit" *around* the axis, near the L1 point, is almost stable, to the point where ISEE-3 spent several years in one and used only a few kilograms of fuel. That's not much worse than Clarke orbit. A halo orbit is actually a complex solar orbit, of course, but looking at it from the Earth, it looks like the spacecraft is orbiting around the Earth-Sun axis. To see why it's called "halo orbit", note that you can do it around the L2 point as well... and if you do it around the Earth-Moon L2 point, then as viewed from the Earth the orbit looks like a halo around the Moon. (Such an orbit is a good place to put a comsat for operations on the lunar farside, since it has a good view of the farside and is far enough from the Earth-Moon axis to be visible from the Earth.) -- C++ is the best example of second-system| Henry Spencer @ U of Toronto Zoology effect since OS/360. | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Tue, 9 Mar 1993 06:29:47 GMT From: Gibson Lam Subject: Rocket Propulsion Newsgroups: sci.space I am a student doing a research project on Goddard, the man who first invented rocket propulsion. Of all the eventual uses that rocket propulsion made possible, such as war missiles or the space shuttle, does anyone think that Goddard should be responsible for the eventual uses of his invention? I would also appretiate any information that you could give me on Goddard or rocket propulsion. ------------------------------ Date: 10 Mar 1993 05:31:11 GMT From: Tim Thompson Subject: Rocket Propulsion Newsgroups: sci.space In article Cnq@eis.calstate.edu, glam@eis.calstate.edu (Gibson Lam) writes: > I am a student doing a research project on Goddard, the man who first > invented rocket propulsion. Of all the eventual uses that rocket > propulsion made possible, such as war missiles or the space shuttle, does > anyone think that Goddard should be responsible for the eventual uses of > his invention? I would also appretiate any information that you could > give me on Goddard or rocket propulsion. Do you mean by "responsible", something like "since rockets were made into weapons of war, It's all Goddard's fault". Or perhaps "Thank Goddard for space flight"? No, I don't think Goddard should be responsible. With precious few exceptions, how can any inventor anticipate the use/misuse to which his/her inventions will be put? --- ALL OPINIONS ARE MINE! ALL MINE !!!! HOWEVER, YOU ARE WELCOME TO SHARE THEM. ------------------------------------------------------------ Timothy J. Thompson, Earth and Space Sciences Division, JPL. Assistant Administrator, Division Science Computing Network. Secretary, Los Angeles Astronomical Society. Member, BOD, Mount Wilson Observatory Association. INTERnet/BITnet: tjt@scn1.jpl.nasa.gov NSI/DECnet: jplsc8::tim SCREAMnet: YO!! TIM!! GPSnet: 118:10:22.85 W by 34:11:58.27 N ------------------------------ Date: Wed, 10 Mar 1993 06:52:05 GMT From: James R Ebright Subject: Rocket Propulsion Newsgroups: sci.space In article glam@eis.calstate.edu (Gibson Lam) writes: > I am a student doing a research project on Goddard, the man who first >invented rocket propulsion. Of all the eventual uses that rocket >propulsion made possible, such as war missiles or the space shuttle, does >anyone think that Goddard should be responsible for the eventual uses of >his invention? As Tom Lehrer once said, "'Once zee rockets are, who cares where zay come down. Zat's not my department' said Werner VonBraun". ;-) Actually, Goddard's work was pretty far removed from the present uses. Putting the blame on him is almost like blaming Shockley for the computer and it's uses. But not everyone can make this defense. VonBraun for example. Goddard, being an American, is often cited by Americans as the father of modern rocketry. But I remember reading somewhere that some of the German scientists debriefed at the end of WWII had never heard of his work... Sometimes the level of technology is just 'ripe' and if one person doesn't do it, someone else soon will. -- Jim Ebright (james.ebright@osu.edu) Lbhe zbgure zngrf bhg bs frnfba :-) Fax # 614-785-0292. Tel # 614-785-0282. Beeper # 614-646-1093 >>> All kids can be educated -- even yours and mine. <<< ------------------------------ Date: 09 Mar 93 22:39:51 GMT From: Alex Howerton Subject: Starprobe Newsgroups: sci.space >>Of course, in order to kill its angular momentum enough >>to get that close to the sun, it may make use of Jupiter for a gravity assist >>(as Ulysses did to get kicked out of the ecliptic plane), at which distance I've got a question that also applies to an earlier discussion about shooting nuclear waste into the sun. If you launched a craft into transfer orbit, then shoot it in the exact opposite direction of Earth's revolution, would that kill the angular momentum? -signed, physics-impaired in Seattle >>it'd need RTG's anyway. ------------------------------ Date: Wed, 10 Mar 1993 04:48:40 GMT From: Henry Spencer Subject: Will Huygens Float Newsgroups: sci.space In article <1nj6o5INNgfj@gap.caltech.edu> kwp@wag.caltech.edu (Kevin W. Plaxco) writes: >... With regard to the >camera ... what are postulated light levels? Don't get your hopes for images *too* high; the system is an atmosphere instrument that does imaging as a sideline, not an optimized imager. Still, it's better than no camera at all... -- C++ is the best example of second-system| Henry Spencer @ U of Toronto Zoology effect since OS/360. | henry@zoo.toronto.edu utzoo!henry ------------------------------ End of Space Digest Volume 16 : Issue 298 ------------------------------