Space Digest Sun, 18 Jul 93 Volume 16 : Issue 890 Today's Topics: Brown Dwarf Companion to Sol? Clementine (ref) European space GPS Altitudes (was: DC-1 & BDB) GPS in space (was Re: DC-1 & BDB) (4 msgs) Hubble, Why the hurry? (2 msgs) It's DEAD, Jim, Bones! Moon Cable/Beanstalk. (3 msgs) Saturn stage names (2 msgs) SOIL PRODUCTION ON MARS Space Movie/PR.. (2 msgs) What's the market for Solar Cells? Why are meteor showers seasonal? 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, 17 Jul 1993 03:04:36 GMT From: "Phil G. Fraering" Subject: Brown Dwarf Companion to Sol? Newsgroups: sci.space lwahl@matt.ksu.ksu.edu (Lynne K Wahl) writes: >Not to mention a brown dwarf would put out a gravitational signature >big enough to disrupt (perturb?) the orbits of the distant planets if >it was this close. Remember, a brown dwarf used to be a *sun*. >For a smaller source such as a Jovian or *very* distant orbiting brown >dwarf, could you examine the orbits of comets? At apogee, the smallest >gravitational disturbance would change the orbit of a comet drastically. Yes, one could do that. People have done it. There is probably a lot to be done still in that (I don't want to discourage anyone from looking). Maybe later I'll look at typing in a local bibliography on the subject. The profs here have done a lot of stuff along these lines... which I need to read up on, come to think of it... (Excuse me...) >-- >--Lynn Wahl lwahl@matt.ksu.ksu.edu | The meek will inherit the >Kansas State University Student | earth, the rest of us are >Soil Conservation Service Computer Specialist | going to the stars. ----* -- +-----------------------+"...for the Gods were engaged in their |"Standard disclaimer" |aeons-long struggle with the Ice Giants, |pgf@srl03.cacs.usl.edu |who had refused to return the lawmmower..." +-----------------------+ ------------------------------ Date: Sat, 17 Jul 1993 20:42:39 GMT From: Remi Cabanac Subject: Clementine (ref) Newsgroups: sci.space Hello netters, I am currently following a summer session at ISU Huntsville Alabama, and I am involved in a project to design a Lunar Farside Observatory. We decided we needed a precursor orbiter and would like info on the Clementine mission. Any help will be appreciated. please write at: cabanac@phy.ulaval.ca or cabanac@isu.uah.edu Thank's ------------------------------ Date: Sat, 17 Jul 93 16:08:00 -0500 From: Charles Radley Subject: European space Newsgroups: sci.space -=> Quoting Dave Stephenson to All <=- Somebody other than David Stephenson said this : >>>Ariane 4 is totally booked up for the next two years, and ariane >>>offers no cost savings on logistics missions compared to Delta or >>>Titan. How come they keep beating their competitors on price then ? DS> drops of course. British Aerospace proposed a 4 man 'super DS> command module' to fly on the Ariane 44 back in 1987. Could have DS> taken 6 back to Earth as crew return vehicle. It got nowhere fast. DS> a. It was British, B. it was like something the Americans had done! DS> c. The french wanted Hermes! David, I think has more to do with the fact that the British government wanted somebody else to pay for it. Britain spends remarkably little on space. ... Internet address:- DJ320@CLEVELAND.FREENET.EDU Ad Astra per Guile ! --- Blue Wave/QWK v2.10 ------------------------------ Date: 18 Jul 1993 13:55:36 +1000 From: Greg Price Subject: GPS Altitudes (was: DC-1 & BDB) Newsgroups: sci.space In <1993Jul8.143103.19186@ucsu.Colorado.EDU> snyderg@spot.Colorado.EDU (SNYDER GARY EDWIN JR) writes: >Seeing the discussion on what altitude The Navstar/GPS system works, I >thought I should give my information gleaned over the last three years. > ... stuff deleted... The US Govt has "strongly" requested >that when a receiver solves a position above 50K ft that it disables its >outputs. This was a hassel with our weather balloon project. A max speed >is also defined, something like mach 1. I bought a Magellan OEM board. Under "Operational Characteristics" it states that max velocity is 950mph (1529 kph) and max accel is 2g. Under Evironmental Characteristics, Altitiude, Operating it states -1000 to +58000 feet (-0.30km to 17.68km). It goes on to say that domestic firmware for 2000000 meters is available. This unit costs about US$500 and does not give you pseudoranges, etc. If you want pseudoranges and other good stuff it costs US$1500 (just a different EPROM I believe) and you have to sign some docs explaining what you intend to do with it, etc, etc. It smells like the US govt has probably had more than a strong word to them. Greg ------------------------------ Date: Sat, 17 Jul 1993 23:36:53 GMT From: Henry Spencer Subject: GPS in space (was Re: DC-1 & BDB) Newsgroups: sci.space In article <1993Jul17.182841.13504@mksol.dseg.ti.com> mccall@mksol.dseg.ti.com (fred j mccall 575-3539) writes: >Remember, there are several modules that the Shuttle can't boost to >higher inclination. You'd need an Energiya launch for those. No, a Proton launch would probably do, although you'd need a new payload fairing. The idea has been discussed. -- Altruism is a fine motive, but if you | Henry Spencer @ U of Toronto Zoology want results, greed works much better. | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Sat, 17 Jul 1993 23:47:52 GMT From: Henry Spencer Subject: GPS in space (was Re: DC-1 & BDB) Newsgroups: sci.space In article <229kmb$e5i@access.digex.net> prb@access.digex.net (Pat) writes: >Reasons for a High Inclination Orbit : > ... >5) Apparently ACRV return is simplified( This is what i was told, > I can't see an intuitive reason why this is). Look at the parts of the globe within 28.5 degrees of the equator. Lots of ocean, lots of desert and jungle, lots of underdeveloped countries with slightly-dubious governments. You'd really like to aim an emergency return at somewhere like the great plains of North America or the Russian taiga+steppe: large areas of flat dry land with hospitable climates, reliable governments, and good search-and-rescue organizations. In a high-inclination orbit, you get repeated shots at such locations every day. -- Altruism is a fine motive, but if you | Henry Spencer @ U of Toronto Zoology want results, greed works much better. | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Sat, 17 Jul 1993 23:53:33 GMT From: Henry Spencer Subject: GPS in space (was Re: DC-1 & BDB) Newsgroups: sci.space In article <229kmb$e5i@access.digex.net> prb@access.digex.net (Pat) writes: >Why is it, cheaper for me to drive to work in DC (Home to the best >public transit system in AMerica) then to take metro. Bad management. :-) I assume "AMerica" refers to the country, not the continent -- Toronto has the best public transit system on the continent, and it's certainly the cheapest way for me to get to work, if you exclude bicycling. (Might be different if I needed a car for other things, but in Toronto you don't.) -- Altruism is a fine motive, but if you | Henry Spencer @ U of Toronto Zoology want results, greed works much better. | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 17 Jul 1993 21:20:18 -0400 From: Matthew DeLuca Subject: GPS in space (was Re: DC-1 & BDB) Newsgroups: sci.space In article <226do3$hcb@access.digex.net> prb@access.digex.net (Pat) writes: >COnsidering we put 1/3rd of our GNP into relying on certain very unstable >arab countries to sell us Oil, I don't see what the problem is. 1.8 trillion dollars a year on Mideast oil? I'd love to see where *that* number came from... -- Matthew DeLuca Georgia Institute of Technology "Do not meddle in the affairs of wizards, Office of Information Technology for they are subtle, and quick to anger." matthew@oit.gatech.edu ------------------------------ Date: Sat, 17 Jul 1993 22:57:03 GMT From: Henry Spencer Subject: Hubble, Why the hurry? Newsgroups: sci.space In article stone@cwis.unomaha.edu (Travis Stone) writes: >>It's not that bad. First, I don't think something that massive would start >>tumbling -- where would the force come from? > >Probably the same place the force came from when they sent up >the---Explorer, I think?---satellite back around 1959 or so: it was >launched with a healthy spin around its long axis, and it had these four >funky antennas attached to it which were pulled straight out by >centrifugal action. The silly thing started to tumble around an axis >perpendicular to its long axis... Note, though, that this was a change in the spin axis -- not a spin-up of a previously-unrotating satellite. More precisely, the spin axis stayed fixed in space, but the satellite's own orientation around it changed. People designing spin-stabilized satellites have to pay careful attention to these issues (see, for example, the Agrawal book in the FAQ bibliography for lots more detail), but spin doesn't come out of nowhere. Starting in a low orbit without significant spin, Hubble would *probably* end up with its long axis aligned with the zenith-nadir axis, due to gravity-gradient torques. (Actually, since I don't think it has any serious damping, it would end up oscillating around that alignment.) The gravity gradient tends to be the dominant torque on an enlongated but fairly dense satellite in low orbit; it's often used to stabilize satellites that don't need precise pointing, e.g. LDEF. -- Altruism is a fine motive, but if you | Henry Spencer @ U of Toronto Zoology want results, greed works much better. | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Sat, 17 Jul 1993 23:28:33 GMT From: Henry Spencer Subject: Hubble, Why the hurry? Newsgroups: sci.space In article <742838750snz@regulus.demon.co.uk> Daves@regulus.demon.co.uk writes: >I think there are two places the force would come from, firstly there will >be the solar radiation pressure on the satellite combined with the residual >atmosphere that could cause the HST to start to rotate. Solar radiation pressure is pretty insignificant in low orbit, although it is a major factor in Clarke orbit. Gravity gradient will be the biggest factor, with atmospheric drag somewhat less significant. >Secondly there are electrical torques caused by the satellite passing >through the Earth's magnetic field lines. The evidence for this is the >tumbling of upper stages whose tumbling rates vary due to just these forces. However, Hubble is designed to use magnetotorquers for momentum dumping, and magnetometers for sensing the field for that purpose -- in fact, the magnetometers are on the "to be replaced" list for the repair mission -- so it's built to have no significant permanent magnetic dipole. -- Altruism is a fine motive, but if you | Henry Spencer @ U of Toronto Zoology want results, greed works much better. | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Sat, 17 Jul 1993 03:38:33 GMT From: "Phil G. Fraering" Subject: It's DEAD, Jim, Bones! Newsgroups: sci.space nsmca@aurora.alaska.edu writes: >Matybe one of the best ideas to get peopel involved with space and science is >to beat them over the head with it.. Such as the SKY BILLBOARD.. I dunno. I think all the people who would want to ignore spaceflight will get upset and lynch anyone who tries. -- +-----------------------+"...for the Gods were engaged in their |"Standard disclaimer" |aeons-long struggle with the Ice Giants, |pgf@srl03.cacs.usl.edu |who had refused to return the lawmmower..." +-----------------------+ ------------------------------ Date: 17 Jul 1993 16:04:20 -0400 From: Pat Subject: Moon Cable/Beanstalk. Newsgroups: sci.space The Last Planetary sized Civil engineering project in 100 years was the Panama Canal. for those not aware, the US GOvt essentially bought Panama from columbia at that time. THey arranged a perpetual canal zone lease (As a sovereign area) and arranged for dozens of protective military installations. They also installed a series of puppet governments. pat -- God put me on this Earth to accomplish certain things. Right now, I am so far behind, I will never die. ------------------------------ Date: Sat, 17 Jul 1993 23:10:39 GMT From: "Phil G. Fraering" Subject: Moon Cable/Beanstalk. Newsgroups: sci.space prb@access.digex.net (Pat) writes: >The Last Planetary sized Civil engineering project in 100 years >was the Panama Canal. for those not aware, the US GOvt >essentially bought Panama Well, helped it get its independance from Columbia. > from columbia at that time. >THey arranged a perpetual canal zone lease (As a sovereign area) >and arranged for dozens of protective military installations. >They also installed a series of puppet governments. In Panama, Columbia, or the U.S.? ;-) >pat >-- >God put me on this Earth to accomplish certain things. Right now, >I am so far behind, I will never die. -- +-----------------------+"And so it went. Tens of thousands of messages, |"Standard disclaimer" |hundreds of points of view. It was not called |pgf@srl03.cacs.usl.edu |the Net of a Million Lies for nothing." +-----------------------+ ------------------------------ Date: Sat, 17 Jul 1993 23:34:57 GMT From: Henry Spencer Subject: Moon Cable/Beanstalk. Newsgroups: sci.space In article <1993Jul17.115237.27343@infodev.cam.ac.uk> sl25@pmms.cam.ac.uk (Steve Linton) writes: >|> >Local govermental problems along the equator... >|> If you've got the sort of money you would need to build a beanstalk... >|> ... you can just buy yourself a suitable local >|> government while you're at it. :-) This will be a minor expense. > >Actually, you will need to buy up, or at least buy off ALL the local governements >along the equator. In a worst-case catastrophe the cable will come down in pieces >the whole way round. Most of it will burn up on reentry. All but the lowest sections will be falling from great heights, and will hit at near-orbital velocities. It ought to be spectacular, but it shouldn't be very dangerous. In any case, you don't *need* the approval of those governments -- they don't have any legal power to stop you -- although it might be smart to buy a bit of insurance against pieces surviving reentry. The only local government whose goodwill you absolutely must have is the one that rules the area where your cable touches down. -- Altruism is a fine motive, but if you | Henry Spencer @ U of Toronto Zoology want results, greed works much better. | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Sun, 18 Jul 1993 00:09:14 GMT From: Henry Spencer Subject: Saturn stage names Newsgroups: sci.space In article <229la7$egu@access.digex.net> prb@access.digex.net (Pat) writes: >Do you happen to know why there is no Saturn Stage marked S-III? >There was the S-I, S-II then S-IV. kind of funny. More properly, there was the S-IC, the S-II, and the S-IVB. This may tip you off to the reason: a complicated history in which many pencilled-in vehicle configurations never became real. The S-IVB was pretty much an enlarged S-IV, and the S-IV was, at one time, going to be the fourth stage of a particular Saturn I configuration. There was great confusion about Saturn I configurations, with many different proposed sets of upper stages and growth paths. The semi-final Saturn I development scheme envisioned a progression of vehicles. You started with an S-I carrying an S-IV. Then you put an S-III in between for a bigger payload. Then you added an S-II between the S-I and S-III for a still bigger payload. (Oh yes, there was an S-V stage as well, which was a modified Centaur.) The stages were named for their role in the final four-stage launcher, of course. The original S-II and S-III were never built, as things finally turned out, and the S-II's name was re-used for the only Saturn stage ever designed from scratch to be a second stage. If you think this is bad, consider that "Saturn C-3" could refer to any of three or four totally different launchers, depending on the date. There were *lots* of paper designs for Saturns, all the way from the one-stage Saturn I (which did in fact fly) to the Saturn C-8 (with eight F-1s in the first stage, practically a Nova, which didn't). -- Altruism is a fine motive, but if you | Henry Spencer @ U of Toronto Zoology want results, greed works much better. | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Sun, 18 Jul 1993 01:08:26 GMT From: Dave Michelson Subject: Saturn stage names Newsgroups: sci.space In article henry@zoo.toronto.edu (Henry Spencer) writes: > >If you think this is bad, consider that "Saturn C-3" could refer to any >of three or four totally different launchers, depending on the date. >There were *lots* of paper designs for Saturns, all the way from the >one-stage Saturn I (which did in fact fly) to the Saturn C-8 (with >eight F-1s in the first stage, practically a Nova, which didn't). Consider also that the Saturn I was originally called the Juno V. It was supposed to use either four E-1 engines or one F-1 engine but neither were available (was the E-1 ever brought to production?) so von Braun decided to cluster eight upgraded Jupiter S3-D engines which were renamed H-1... -- Dave Michelson -- davem@ee.ubc.ca -- University of British Columbia ------------------------------ Date: Sat, 17 Jul 1993 22:59:18 GMT From: Henry Spencer Subject: SOIL PRODUCTION ON MARS Newsgroups: sci.space In article <227n1h$6v7@agate.berkeley.edu> gwh@soda.berkeley.edu (George William Herbert) writes: >... Ways to get Mars >an atmosphere are indeed being looked at, see for instance various >papers in the soon-to-be-published Case for Mars V proceedings >and the Case IV and III proceedings... Another good source is JBIS -- the Journal of the British Interplanetary Society -- which has published several special issues on terraforming in the last year or two. -- Altruism is a fine motive, but if you | Henry Spencer @ U of Toronto Zoology want results, greed works much better. | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: Sat, 17 Jul 1993 03:40:45 GMT From: "Phil G. Fraering" Subject: Space Movie/PR.. Newsgroups: sci.space sreardon@bradley.bradley.edu (Steven Reardon) writes: >How about Space Camp c. 1987 (?) It was c. 1986 and hit the theaters just as everyone could see that a lot of the stuff there was, er, slightly misleading. >>It would be a grewat publicity plou to get people interested in space research. >I've been thinking about this recently, and I have to disagree. I think that >all of the popular movies and TV shows about space (a la Star Trek) do more >harm than good in terms of public interest in space exploration. >I think that John/Jane Q. Public has a *grossly* exaggerated idea of what >is possible in terms of space/technology because of these shows. I did a >survey recently (totally unscientific) which showed 75% of respondents didn't >know that the shuttle couldn't go to the moon. The rest didn't know why. Actually, my experience shows the exact opposite. The public has been led to believe that spaceflight is increadibly hard, and that 15 billion dollars has to be spent a year just to send a minimal amount of people to low earth orbit... >I also think these shows allow people to get their space interest out of >their systems. They don't need the excitement of the U.S. (or anybody) >returning to the moon when Picard, Data, Ryker (sp?), and company are going >off to Regula 6 on monday night. >Don't get me wrong. I personally like these shows, but I don't think they >do any good in terms of PR for the space program. >Steve Well, consider the way they portray space exploration as something that'll happen only after we get warp drive or transporters or something else along the lines of new physics we probably won't get. Although there is a slight possibility that wormholes could pan out or something... we just don't seem to know anything. And some of the speculation there is _very_ interesting. >-- >I'm going to change my last name to Peece, >and name my first son Warren. >sreardon@bradley.bradley.edu -- Steven Reardon Bradley U -- Peoria IL -- +-----------------------+"And so it went. Tens of thousands of messages, |"Standard disclaimer" |hundreds of points of view. It was not called |pgf@srl03.cacs.usl.edu |the Net of a Million Lies for nothing." +-----------------------+ ------------------------------ Date: Sat, 17 Jul 1993 05:15:11 +1200 (NZST) From: Bruce Hoult Subject: Space Movie/PR.. Newsgroups: sci.space nsmca@aurora.alaska.edu writes: > Or maybe a high budget First Contact with Aliens.. not a "V" or soem such, but > a first contact that is a bit more up to modern tech/current tech, and > possibilties _Footfall_ could make a good movie, I think. It's got pretty nifty and well-thought- out aliens. For that matter, so has _The Mote in God's Eye_. >Maybe this time the Government and NASA can play the good guys.. Oh. I didn't realise you were thinking of a fantasy... ------------------------------ Date: 17 Jul 93 18:58:56 GMT From: AJ Madison Subject: What's the market for Solar Cells? Newsgroups: sci.space In article <224ls5$l31@menudo.uh.edu>, svecp@Rosie.UH.EDU (dave moore) writes: > > I'm trying to gather information about the market for solar cell > applications in space. > > - I suspect the market is inelastic, that is, variations in cell cost > wouldn't affect the number of panels built & sold very much. > Is that a good assumption? Not that long ago, I saw something on PBS, where this new company was making solar cells in sheets. It was cheap and nearly indestructable. The guy who's the company's ceo (and apparently chief salesman) did this demo where he had 1 square foot of this stuff powering a moderate sized boom box and drove a nail through the sheet and the boom box kept playing. My point is, if the cells get cheap enough, they may have applications here on earth. If you consider what one is looking for in space applications (durability, lightweight, reliability, redundancy) are equally desirable here on earth, the only big problem is cost. > > - Would ANY factors make a difference? Or is the market totally > driven by the number of satellites flown each year? > On a variation of the above, for instance, various power company utilities used to put in very expensive transformers to step down High Voltage lines to a power level suitable for their transmission line diagnostic and monitoring hardware. Solar cells have gotten cheap enough, that its cheaper to mount a solar array to power their diagnostic gear. Knowing that, I started looking closer at the boxes at the top of electric poles and high tension towers. Every so often, you'll see a little solar array ontop of the box. Of couse, power companies are very motivated to keep costs down, so they're more pragmatic (or creative) than some organizations. ------------------------------ Date: Sat, 17 Jul 1993 23:24:04 GMT From: Henry Spencer Subject: Why are meteor showers seasonal? Newsgroups: sci.space In article daf@bbn.com (David Fagan) writes: >... Why do particular metor showers recur at the same time of >year? > >... The only answer that leaves me is >that there is an asteroid belt (or many belts) which cross the earths >orbit... Sort of right. Part of the junk spewed off comets is dust (plus occasional larger pebbles and such). This stuff comes off with fairly small relative velocities, so it stays in pretty much the same orbit as the comet. On the other hand, there is *some* velocity difference, so the orbital periods are not quite the same, and the dust spreads out along the comet's orbit over time. The result is a sort of micro-asteroid belt of dust particles (with occasional larger lumps) centered on the comet's orbit. If that orbit happens to intersect Earth's, then you get a meteor shower every time Earth passes through it -- which naturally happens once a year at about the same time every year -- with the meteors all coming from about the same direction. Some of the known meteor showers are definitely associated with known comets -- in some cases, with comets that broke up and died out in historic times. The rest are relics of extinct comets. The most frustrating part of all this is that a given shower's intensity is hard to predict, because the belts of dust and debris aren't uniform. When Earth happens to pass through a dense area, we get a meteor storm. We can make educated guesses about storms in some cases. For example, the encounter with the Perseids this year will be exceptionally favorable -- Earth will come very close to the comet's orbit not long after the comet itself went past -- and the last time this happened there was a storm. (Around 0100 GMT on Aug 12 -- evening of the 11th in North America -- will be a good time to be in a dark area and watching the sky.) But the detailed structures of the belts are unknown, and nobody can be sure. For example, the Leonids peak about every 33 years, and the 1833 storm was so spectacular that it caused worldwide panic, but the storms were thought to be dying out when the 1900s peak and the 1930s peak produced nothing much... and then the 1960s peak produced a storm. (The next Leonids peak will be late this decade.) -- Altruism is a fine motive, but if you | Henry Spencer @ U of Toronto Zoology want results, greed works much better. | henry@zoo.toronto.edu utzoo!henry ------------------------------ From: Pat Newsgroups: sci.space Subject: Re: message from Space Digest Date: 17 Jul 1993 15:55:30 -0400 Organization: Express Access Online Communications, Greenbelt, MD USA Lines: 10 Distribution: sci Message-Id: <229lfi$elm@access.digex.net> References: Nntp-Posting-Host: access.digex.net Sender: news@CRABAPPLE.SRV.CS.CMU.EDU Source-Info: Sender is really isu@VACATION.VENARI.CS.CMU.EDU My neighbor works for the IMF. we are debating when the IMF will take over the US GOvernment. It's Like GM, the bigger they are the longer they go, before the problems show up. pat -- God put me on this Earth to accomplish certain things. Right now, I am so far behind, I will never die. ------------------------------ End of Space Digest Volume 16 : Issue 890