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/usr1/ota/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr1/ota/space/space.dl) (->ota+space.digests) ID ; Tue, 12 Sep 89 20:17:37 -0400 (EDT) Message-ID: Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Tue, 12 Sep 89 20:17:15 -0400 (EDT) Subject: SPACE Digest V10 #33 SPACE Digest Volume 10 : Issue 33 Today's Topics: Voyager's Interstellar Itinerary Re: Galileo Jovian atmospheric probe -- is it sterilized??? Jumping on the moon Re: Face on Mars Was Voyager another damaging Apollo one-shot? Private launch costs Re: Was Voyager another damaging Apollo one-shot? RE: Voyager's images Re: Message on Mars ---------------------------------------------------------------------- Date: Fri, 1 Sep 89 11:15 EST From: Subject: Voyager's Interstellar Itinerary Terry Hancock writes: >>The answer was that in 8,000 years it will fly by Barnard's Star, in 20,000 or >>so it will pass Proxima Centauri, and then the Oort cloud. > > Okay, so this is completely wrong. No, it isn't. Just incomplete to the point of near incomprehesibility. But then, what do you expect from TV commentators. Their info has been regurgitated and digested so often, there is nothing left from which anyone can learn anything. The following is the detail missing in the above statement, taken from The Planetary Report: Year Event 8571 Closest approach to Barnard's Star - 4.03 ly away! 0.42 ly from the Sun. 20319 Closest approach to Proxima Centauri - 3.21 ly away. 1.00 ly from the Sun. 20629 Closest approach to Alpha Centauri - 3.47 ly away. 1.02 ly from the Sun. 23274 Closest approach to Lalande 21185 - 4.65 ly away. 1.15 ly from the Sun. 26262 Enter Oort cloud. This seems real fishy to me, especially since no one agrees where the Oort cloud actually is located. 28635 Exits Oort cloud and Solar System. 129084 Closest approach to Ross 154 - 5.75 ly away. 6.39 ly from the Sun. 296036 Closest approach to Sirius - 4.32 ly away. 14.64 ly from the Sun. 442385 Closest approach to 44 Ophiuchi - 6.72 ly away. 21.88 ly from the Sun. 957963 Closest approach to DM+27 1311 - 6.62 ly away. 47.38 ly from the Sun. Personally, I wouldn't trust the numbers past about 60000 years - there are still too many unknown possibilities for gravitational influences. -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- | Arnold Gill | | Queen's University at Kingston | | BITNET: gill@qucdnast | | INTERNET: gill@qucdnast.queensu.ca | -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- ------------------------------ Date: 1 Sep 89 22:43:31 GMT From: bfmny0!tneff@uunet.uu.net (Tom Neff) Subject: Re: Galileo Jovian atmospheric probe -- is it sterilized??? Re: the Galileo contamination threat, I agree it would be a terrible mishap to infect Jupiter (and buddy, if there ARE beings there do you want to get them mad at Earth?!!), but I suspect the worriers are missing the event sequence. My understanding is that most agree any exterior microbes will be 86'd en route and during entry; that the surviving ones would be in the probe interior. The probe will pass through possibly viable zones, and will also be crushed in the atmosphere so as to breach the interior, BUT it will long since have left the viable zones before being crushed. In the viable zones it'll just be a falling cone of metal whizzing by between lethal gases. There shouldn't be too much opportunity for infection at that point. I also think we shouldn't take too much responsibility for keeping Jupiter pristine. Junk flies all over the solar system, as witness the Mars "sample return missions" to the Ross ice shelf. Jupiter's probably seen it all before. Let's just hope we don't get a huge JOVIAN probe cone-ing down into our atmosphere in retaliation a couple of years from now! :-) -- Annex Canada now! We need the room, \) Tom Neff and who's going to stop us. (\ tneff@bfmny0.UU.NET ------------------------------ Date: Fri, 1 Sep 89 19:50:34 EDT From: John Roberts Disclaimer: Opinions expressed are those of the sender and do not reflect NIST policy or agreement. Subject: Jumping on the moon Several people have recently posted calculations of how far it would be possible to hit a golf ball on the moon. A more interesting (to me :-) problem: how high would it be possible to jump on the moon? Assume a pressurized gymnasium with a solid floor, and ignore wind resistance. (If that bothers you, assume a pure oxygen atmosphere at 1/5 standard pressure, which would greatly reduce resistance.) By experimentation, I have estimated that it would not be too difficult for a typical healthy person on earth to make a standing jump of 1.5 feet (raising the center of gravity by that amount. A person jumping on the moon and leaving the floor at the same velocity could jump about six times as high, or about 9 feet. However, much of the energy of a jump on earth goes into counteracting the force of gravity during the initial acceleration, while this effect would be greatly reduced on the moon. There is a limit to how fast the legs could extend even under a reduced load, but I estimate that it should not be too difficult to double the initial velocity, which would make it possible to jump about 24 times as high on the moon as on earth, or about 36 feet (!) It is also apparent that it would be much easier to get injured or killed trying this experiment on the moon, since the total "hang time" would be increased from about .6 seconds to about 7.4 seconds, allowing plenty of time to rotate and land sideways or upside down, at a velocity of about 20 feet per second. Visitors to the moon will have to learn free-fall maneuvers before they attempt gymnastic routines. John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: 1 Sep 89 21:39:52 GMT From: agate!codon1.berkeley.edu!mkkuhner@ucbvax.Berkeley.EDU (Mary K. Kuhner;335 Mulford) Subject: Re: Face on Mars In article <570@tahoma.UUCP> jpg3196@tahoma.UUCP (James P. Galasyn) writes: >I was not impressed by the abstract posted here awhile back. A couple >year ago, _Omni_ printed an article about the Face, full of beautiful >computer-enhanced images of the thing, but I figured that it could be >an accident if that's all there was: a Face in the desert. Also, it >was _Omni_. There is a big problem with computer enhanced images of the Face, as pointed out by an article in _Skeptical Enquirer_ last year. The original transmission was digital; it gave a darkness for each pixel in the screen. If you see an original it is clear that certain pixels came out black for transmission-failure reasons. Logically, what can computer enhancement do with such a picture? It can fill in the black pixels with their adjacent color, which definately makes the picture look better. Other than that, it is not obvious that the picture can be improved. Where is the new information coming from? Computer enhancement is good at removing regular static or at making small differences of shade larger, but that's not what is wrong with the Face picture--it just doesn't have enough pixels in it to show the object very clearly. Mary Kuhner mkkuhner@enzyme.berkeley.edu ------------------------------ Date: 1 Sep 89 22:32:40 GMT From: bfmny0!tneff@uunet.uu.net (Tom Neff) Subject: Was Voyager another damaging Apollo one-shot? This is an heretical thought, but I wonder if the Grand Tour wasn't the unmanned equivalent of the Kennedy space race and its resulting one-shot lunar landing program -- in the sense that, having rushed ahead to grab the dessert, we found ourselves in no mood to continue eating our vegetables, i.e., building a solid and lasting program. I mean after all, think about it -- NOW what can JPL do that will grab the attention of the man in the street? We've crammed the joy of discovery of every major planet into the space of about 15 years. Everything else from now on is going to look boring or repetitive by comparison -- oh, ANOTHER picture of Jupiter on the front page, Martha, didn't they do that a couple of years ago? The Apollo 16 Syndrome. Now impressing the man in the street isn't the #1 priority of planetary exploration, natch -- it's scientific knowledge. But the bucks could be hard to come by. I'm just a little afraid that NASA has managed to outsmart itself by doing such a comprehensive job with a couple of probes. Just pray *we* don't pull a FOBOS number or things will get VERY tough. -- Annex Canada now! We need the room, \) Tom Neff and who's going to stop us. (\ tneff@bfmny0.UU.NET ------------------------------ Date: Fri, 1 Sep 89 20:23:06 EDT From: John Roberts Disclaimer: Opinions expressed are those of the sender and do not reflect NIST policy or agreement. Subject: Private launch costs >From: mailrus!jarvis.csri.toronto.edu!utgpu!utzoo!henry@tut.cis.ohio-state.edu (Henry Spencer) >Subject: Re: Re: Contractors >In article <8908232056.AA26648@cmr.ncsl.nist.gov> roberts@CMR.NCSL.NIST.GOV (John Roberts) writes: >>still considerably different from the claims by some people that the >>expansion of private launch services will almost immediately cause launch >>costs to drop by a factor of 50 (or 100 or 1000). >Have you heard anyone claiming that? I haven't. By the more responsible contributors to the list, trying to make a serious estimate, no. As wild exaggerations, or as a necessary corollary to some of the proposals (such as growing food crops in orbit for use on earth), yes. There sometimes seems to be an implicit assumption that nearly all of the cost of a government launch is from bureaucratic red tape, "excessive" safety and reliability measures, and deliberate overpricing (all of which may be somewhat true), and that private launch companies (being entirely free of all of these problems :-) would immediately lower launch costs to a tiny fraction of their current rates. I get the impression that those on the list who have given the matter more thought hope that prices will go down by a factor of ten or so within a few years, which I would consider very optimistic but still possible. Since private launch services are really just getting started, price trends should be a lot more obvious in two or three years. >What I have heard, and >have claimed, is that such cost reductions are well within the bounds of >possibility within, say, a decade, given a solid competitive market with >volume, say, comparable to that of the USSR's normal launch schedule. >We don't have that yet. Those who like to describe the advantages of the Soviet space program point out the extreme importance of economies of scale in obtaining inexpensive launch services. Looking at unmanned launches (the market for private launch services in the forseeable future), the USSR owes nearly all of its launch volume to military missions. What are the most plausible scenarios for increasing the US launch volume to a high level in the near future? An increased military presence in space such as SDI is one possibility, but many space enthusiasts would find it distasteful to push for this in the hopes of lowering launch costs. The commercial market is still fairly limited, though lowering launch prices *before* launch costs come down (in other words, subsidies from the government or from existing large corporations) could increase its rate of expansion. Using private launches for most of the parts of a space station (NASA or other) is another possibility. Perhaps NASA could concentrate on putting together a large number of inexpensive space probes (rather than a few expensive ones) in order to raise the total volume (they may be thinking about this already). Another problem: the USSR has just one "company" to supply all its launch needs. If the US has 10 private launch companies, will it have to have 10 times the USSR's launch volume for all the companies to have good economy of scale? John Roberts roberts@cmr.ncsl.nist.gov ------------------------------ Date: 2 Sep 89 03:28:56 GMT From: uhccux!goldader@ames.arc.nasa.gov (Jeff Goldader) Subject: Re: Was Voyager another damaging Apollo one-shot? In article <14616@bfmny0.UUCP> tneff@bfmny0.UU.NET (Tom Neff) writes: >This is an heretical thought, but I wonder if the Grand Tour wasn't >the unmanned equivalent of the Kennedy space race and its resulting >one-shot lunar landing program -- in the sense that, having rushed >ahead to grab the dessert, we found ourselves in no mood to continue >eating our vegetables, i.e., building a solid and lasting program. > >I mean after all, think about it -- NOW what can JPL do that will grab >the attention of the man in the street? > >Now impressing the man in the street isn't the #1 priority of planetary >exploration, natch -- it's scientific knowledge. But the bucks could >be hard to come by. I'm just a little afraid that NASA has managed to >outsmart itself by doing such a comprehensive job with a couple of >probes. > >-- >Annex Canada now! We need the room, \) Tom Neff > and who's going to stop us. (\ tneff@bfmny0.UU.NET Fer cryin' out loud, Tom, **WHAT DO YOU WANT**?!?!? Would you prefer that we never learned anything about anything just because someone would then figure we knew it all about everything? We have just *barely* scratched the surface with the Voyagers. You saw those Triton images, right? Well, that is only *25%* of the surface of the satellite. We barely looked at Nereid. We haven't obtained decent resolution (sub-km) for almost all of the satellites Voyager saw. We haven't done any long-term studies of the weather of the Jovian planets, we haven't (yet) sent probes into any of their atmospheres, we haven't snooped around their ring systems with orbiters, we haven't obtained any in-situ infrared imaging. We haven't sent landers down to any of the moons yet (and have plans to do so only in Titan's case)... I could go on for hours! These are all *incredibly* exciting things! Comprehensive? Heck, this is just a first tantalizing glimpse! I think (from some of your previous postings) that you would really like to see these things; I'm not accusing you of being against exploration, far from it. I am just trying to give some reasons that, not only are we not finished, we have just barely started. Anyone want to see a Neptune orbiter in 2018? We can do it if we launch in 1998, according to Andy Ingersoll (sp?) of the Voyager imaging team. If you want some action, call your congresscritters, thank them/press them for their support of CRAF/Cassini, and tell them that, with a duplicate of Cassini, we can have a Neptune orbiter. It takes a long time to get to the planets. Now that we have Galileo and Magellan going, and very probably CRAF/Cassini, we need to start looking at follow-on missions. Voyager was the initial reconaissance; now, let's do the real work! Jeff Goldader University of Hawaii uhifa.ifa.hawaii.edu Institute for Astronomy "So, Lonestar, now you see that Evil will always win- because Good is stupid." -The Dark Lord Dark Helmet, _SPACEBALLS_ Disclaimer: The opinions expressed herein are my responsibility alone. The University of Hawaii and the Institute for Astronomy neither support nor are in *any way* responsible for these opinions. ------------------------------ Date: Fri, 01 Sep 89 11:01:26 EDT From: Walter Giesbrecht Subject: RE: Voyager's images In response to the query regarding the availability of Voyager images from NASA, there was mention in the June 1988 issue of Byte that some of this stuff was available on CD-ROM. Specifically, there are two discs -- one featuring images of Uranus, and the other featuring data & images from all over the solar system. The product is (was?) known as "Planetary Data System Space Science Sampler", and is available from NASA JPL 4800 Oak Grove Dr. Pasadena, CA 91109 (818) 354-6347 ------------------------------ Date: Fri, 1 Sep 89 10:03:56 PDT From: Peter Scott Subject: Re: Message on Mars In article <1989Aug14.075559.4965@agate.berkeley.edu>, web@garnet.berkeley.edu (William Baxter) writes: > I have before me a post card which bears the profile of John F. Kennedy. > The startling likeness is a rock formation on the island of Maui, > Hawaii. JFK certainly gets around. There is a rock near Colorado Springs which looks just like him. I don't know if there are postcards, but it is signposted. There are many rock formations on Earth that resemble real objects much better than anything on Mars (town near here: "Eagle Rock"; guess why). Just wind and water erosion. Same elements are/were available on Mars. Peter Scott (pjs@grouch.jpl.nasa.gov) ------------------------------ End of SPACE Digest V10 #33 *******************