Date: Thu, 3 Sep 92 05:06:34 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #163 To: Space Digest Readers Precedence: bulk Space Digest Thu, 3 Sep 92 Volume 15 : Issue 163 Today's Topics: Antarctica (was: SPS) (4 msgs) Inflatable Space Stations - Why Not ? soviet rovers on mars space digest 156 troncated Space FAQ 11/15 - Upcoming Planetary Probes What is the speed of light measured from? Who went to Rio With telepresence, who needs people in Earth orbit? 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: 2 Sep 92 22:49:07 GMT From: Frank Crary Subject: Antarctica (was: SPS) Newsgroups: sci.space In article <1992Sep2.144506.19052@dartvax.dartmouth.edu> Frederick.A.Ringwald@dartmouth.edu (Frederick A. Ringwald) writes: >Yes, and it puzzles me: why are people who wax rhapsodic about living >in space not more enthusiastic about Antarctica? You don't even have to >make your own air and water in Antarctica! You actually do have to "make" (more properly melt) your own water there. (Except at the big stations like MacMurdo and Mirny.) Antarctica isn't popular for two reasons (asside from it's lack of glamor): It has already been explored and all colonization/private property is _illegal_ under international treaty. (The phrasing of the treaty, by the way, was fairly similar to the space treaty the United States refused to ratify.) Frank Crary CU Boulder ------------------------------ Date: 2 Sep 92 23:43:11 GMT From: Matthew DeLuca Subject: Antarctica (was: SPS) Newsgroups: sci.space In article <1992Sep2.224907.1937@ucsu.Colorado.EDU> fcrary@ucsu.Colorado.EDU (Frank Crary) writes: >Antarctica isn't popular for two reasons (asside from it's lack of >glamor): It has already been explored and all colonization/private >property is _illegal_ under international treaty. (The phrasing of >the treaty, by the way, was fairly similar to the space treaty the >United States refused to ratify.) Besides, there's gravity in Antarctica; I think some of the mystique of space exploration and colonization is the fact that when you are floating in the middle of your spacecraft of habitat, you know you aren't in Kansas anymore. With just freezing weather and snow and ice, you could be in Toronto for all you can tell the difference. :-) -- Matthew DeLuca "I'd hire the Dorsai, if I knew their Georgia Institute of Technology P.O. box." Office of Information Technology - Zebediah Carter, Internet: ccoprmd@prism.gatech.edu _The Number of the Beast_ ------------------------------ Date: 3 Sep 92 04:39:51 GMT From: "Frederick A. Ringwald" Subject: Antarctica (was: SPS) Newsgroups: sci.space In article <1992Sep2.224907.1937@ucsu.Colorado.EDU> fcrary@ucsu.Colorado.EDU (Frank Crary) writes: > It has already been explored So has the Moon, albeit to a lesser extent. > and all colonization/private > property is _illegal_ under international treaty. Come on: since when did that ever stop anyone? If it became technologically feasible to make a profit from extracting petroleum there, that treaty would be abrogated faster than Greenpeace could let out a good whine. Besides, most international treaties can be LEGALLY abrogated, given 90 days' notice. ------------------------------ Date: 3 Sep 92 04:45:47 GMT From: "Frederick A. Ringwald" Subject: Antarctica (was: SPS) Newsgroups: sci.space In article <67523@hydra.gatech.EDU> ccoprmd@prism.gatech.EDU (Matthew DeLuca) writes: > Besides, there's gravity in Antarctica; I think some of the mystique > of space exploration and colonization is the fact that when you are > floating in the middle of your spacecraft of habitat But micro-g gives every indication of being unhealthy; and if you can live there permanently, you might be stuck there permanently. (From bone demineralization, not from space colonization turning into the ultimate slavery; although I have been taken advantage of so many times and so badly in the name of space, I can't discount the latter.) ------------------------------ Date: 1 Sep 92 19:26:34 GMT From: Russell Katz Subject: Inflatable Space Stations - Why Not ? Newsgroups: sci.space This is a bit related to the topic...I think. I have read in several sf stories about using the shuttle main tanks as modules for space habitats...just having the shuttle carry the tank with it into orbit. Some authors stated that it would not take any extra fuel(??) to do so. Any of you experts out there have an answer as to why NASA doesn't use the tanks as at least a temporary habitation? ************************************************************************* * The Crystal Wind is the Storm, * Daniel K. Moran: * Russell Katz * * and The Storm is Data, * "Emerald Eyes" * katzr@ucs.orst.edu* * and the Data is Life. * and * * * -The Player's Litany * "The Long Run" * * ************************************************************************* ------------------------------ Date: 3 Sep 92 03:10:00 GMT From: "John A. Weeks III" Subject: soviet rovers on mars Newsgroups: sci.space In article <1992Sep2.900.2102@ALMAC> bill.edwards@almac.co.uk writes: > The Soviets maintained for many years that Gagarin did not eject - > something to do do with claiming the record - but later, it is reported, > admitted he did. I read something about this in one of the NASM exhibits. The flight did not count as a record unless you land with your craft. I guess I personally do not whether Gagarin ejected or not--it was still a very impressive feat that the Soviets pulled off. I have also heard a rumor that Gagarin's flight did not complete an entire orbit, and the Soviets supposedly airlifted his capsule a few hundred miles to the east to make it appear that they completed a full orbit. Has anyone else heard this? -john- -- ============================================================================== John A. Weeks III (612) 942-6969 john@newave.mn.org Newave Communications, Ltd. ..!uunet!tcnet!newave!john ------------------------------ Date: Thu, 3 SEP 92 10:14 N From: LUNAZZI@BOIFCC.CINECA.IT Subject: space digest 156 troncated Date sent: 4-SEP-1992 21:12:57 I receive space digest 156 troncated. This is the end of the digest: > It was a very successful test of this probe design. At 225-plus > days, ZOND 3 was also the longest-surviving Soviet lunar or planetary > probe to date, beating the previous record holder, MARS 1, by almost > three months. Ironically, its Venus-bound sister probes did not fare > as well. VENERA 2, launched on November 12, which carried the same > instruments as ZOND 3, failed just as it was to perform its photo- > graphing session of Venus on February 27, 1966, after a flight of > >------------------------------ > >End of Space Digest Volume 15 : Issue 156 >------------------------------ Please, would you remail to me the article "THE GREAT MOON RACE: THE LONG ROAD TO SUCCESS" ? Thanks Mauro |===================================| /\ |Mauro Andrea Cremonini (IW4BOX) | //\\ |Dept. Organic Chemistry | ///\\\ |University, Bologna, ITALY | \\\/// |e-mail lunazzi@boifcc.cineca.it | \\// |===================================| \/ ------------------------------ Date: 2 Sep 92 18:58:25 GMT From: Jon Leech Subject: Space FAQ 11/15 - Upcoming Planetary Probes Newsgroups: sci.space,news.answers Archive-name: space/new_probes Last-modified: $Date: 92/09/02 14:48:23 $ UPCOMING PLANETARY PROBES - MISSIONS AND SCHEDULES Information on upcoming or currently active missions not mentioned below would be welcome. Sources: NASA fact sheets, Cassini Mission Design team, ISAS/NASDA launch schedules, press kits. GALILEO - Jupiter orbiter and atmosphere probe, in transit. Has returned the first resolved images of an asteroid, Gaspra, while in transit to Jupiter. Efforts to unfurl the stuck High-Gain Antenna (HGA) are continuing, though eventual success appears less likely. If the HGA cannot be unfurled, JPL has developed a backup plan using data compression (JPEG-like for images, lossless compression for data from the other instruments) which should allow the mission to achieve approximately 70% of its objectives. Galileo Schedule ---------------- 10/18/89 - Launch from Space Shuttle 02/09/90 - Venus Flyby 10/**/90 - Venus Data Playback 12/08/90 - 1st Earth Flyby 05/01/91 - High Gain Antenna Unfurled 07/91 - 06/92 - 1st Asteroid Belt Passage 10/29/91 - Asteroid Gaspra Flyby 12/08/92 - 2nd Earth Flyby 05/93 - 11/93 - 2nd Asteroid Belt Passage 08/28/93 - Asteroid Ida Flyby 07/02/95 - Probe Separation 07/09/95 - Orbiter Deflection Maneuver 12/95 - 10/97 - Orbital Tour of Jovian Moons 12/07/95 - Jupiter/Io Encounter 07/18/96 - Ganymede 09/28/96 - Ganymede 12/12/96 - Callisto 01/23/97 - Europa 02/28/97 - Ganymede 04/22/97 - Europa 05/31/97 - Europa 10/05/97 - Jupiter Magnetotail Exploration MAGELLAN - Venus radar mapping mission. Has mapped almost the entire surface at high resolution. Funding for continuing operations into mapping cycle 4 and beyond has been cut from the proposed NASA budget. MARS OBSERVER - Mars orbiter including 1.5 m/pixel resolution camera. Launch scheduled 9/16/1992 aboard Titan III; arrival in 8/93, operations start 11/93 for one martian year (687 days). TOPEX/Poseidon - Joint US/French Earth observing satellite, launched in August 1992 on an Ariane 4 booster. The primary objective of the TOPEX/POSEIDON project is to make precise and accurate global observations of the sea level for several years, substantially increasing understanding of global ocean dynamics. The satellite also will increase understanding of how heat is transported in the ocean. CASSINI - Saturn orbiter and Titan atmosphere probe. Cassini is a joint NASA/ESA project designed to accomplish an exploration of the Saturnian system with its Cassini Saturn Orbiter and Huygens Titan Probe. Cassini is scheduled for launch aboard a Titan IV/Centair in October of 1997. After gravity assists of Venus, Earth and Jupiter in a VVEJGA trajectory, the spacecraft will arrive at Saturn in June of 2004. Upon arrival, the Cassini spacecraft performs several maneuvers to achieve an orbit around Saturn. Near the end of this initial orbit, the Huygens Probe separates from the Orbiter and descends through the atmosphere of Titan. The Orbiter relays the Probe data to Earth for about 3 hours while the Probe enters and traverses the cloudy atmosphere to the surface. After the completion of the Probe mission, the Orbiter continues touring the Saturnian system for three and a half years. Titan synchronous orbit trajectories will allow about 35 flybys of Titan and targeted flybys of Iapetus, Dione and Enceladus. The objectives of the mission are threefold: conduct detailed studies of Saturn's atmosphere, rings and magnetosphere; conduct close-up studies of Saturn's satellites, and characterize Titan's atmosphere and surface. One of the most intriguing aspects of Titan is the possibility that its surface may be covered in part with lakes of liquid hydrocarbons that result from photochemical processes in its upper atmosphere. These hydrocarbons condense to form a global smog layer and eventually rain down onto the surface. The Cassini orbiter will use onboard radar to peer through Titan's clouds and determine if there is liquid on the surface. Experiments aboard both the orbiter and the entry probe will investigate the chemical processes that produce this unique atmosphere. The Cassini mission is named for Jean Dominique Cassini (1625-1712), the first director of the Paris Observatory, who discovered several of Saturn's satellites and the major division in its rings. The Titan atmospheric entry probe is named for the Dutch physicist Christiaan Huygens (1629-1695), who discovered Titan and first described the true nature of Saturn's rings. Key Scheduled Dates for the Cassini Mission (VVEJGA Trajectory) ------------------------------------------------------------- 10/06/97 - Titan IV/Centaur Launch 04/21/98 - Venus 1 Gravity Assist 06/20/99 - Venus 2 Gravity Assist 08/16/99 - Earth Gravity Assist 12/30/00 - Jupiter Gravity Assist 06/25/04 - Saturn Arrival 01/09/05 - Titan Probe Release 01/30/05 - Titan Probe Entry 06/25/08 - End of Primary Mission (Schedule last updated 7/22/92) OTHER SPACE SCIENCE MISSIONS (note: this is based on a posting by Ron Baalke in 11/89, with ISAS/NASDA information contributed by Yoshiro Yamada (yamada@yscvax.ysc.go.jp). I'm attempting to track changes based on updated shuttle manifests; corrections and updates are welcome. 1992 Missions o Spacelab Japan [Sep, STS-47 SL-J] o Laser Geodynamics Satellite [Sep, STS-52 LAGEOS II] o Mars Observer [Sep, Titan III rocket] September by rocket, to study Mars' climate and surface. o ASTRO-D (Astronomy Satellite-D) [ISAS] Conducting precise observations of the X-ray images and X-ray spectra of various heavenly bodies. o GEOTAIL (Geophysical Tail) [ISAS/NASA, July, Delta II rocket] The Geomagnetic Tail Observation Satellite for engaging in observations of the structure and dynamics of the solar wind and extending from the night side of the earth. This spacecraft is to be launched by the United States. GEOTAIL is a collaborative program with NASA and of USA. 1993 Missions o Wind [Aug, Delta II rocket] Satellite to measure solar wind input to magnetosphere. o Space Radar Lab [Sep, STS-60 SRL-01] Gather radar images of Earth's surface. o Total Ozone Mapping Spectrometer [Dec, Pegasus rocket] Study of Stratospheric ozone. o SFU (Space Flyer Unit) [ISAS] Conducting space experiments and observations and this can be recovered after it conducts the various scientific and engineering experiments. SFU is to be launched by ISAS and retrieved by the U.S. Space Shuttle on STS-68 in 1994. 1994 o Polar Auroral Plasma Physics [May, Delta II rocket] June, measure solar wind and ions and gases surrounding the Earth. o IML-2 (STS) [NASDA, Jul 1994 IML-02] International Microgravity Laboratory. o ADEOS [NASDA] Advanced Earth Observing Satellite. o MUSES-B (Mu Space Engineering Satellite-B) [ISAS] Conducting research on the precise mechanism of space structure and in-space astronomical observations of electromagnetic waves. 1995 LUNAR-A [ISAS] Elucidating the crust structure and thermal construction of the moon's interior. Proposed Missions: o Advanced X-ray Astronomy Facility (AXAF) Possible launch from shuttle in 1995, AXAF is a space observatory with a high resolution telescope. It would orbit for 15 years and study the mysteries and fate of the universe. o Earth Observing System (EOS) Possible launch in 1997, 1 of 6 US orbiting space platforms to provide long-term data (15 years) of Earth systems science including planetary evolution. o Mercury Observer Possible 1997 launch. o Lunar Observer Possible 1997 launch, would be sent into a long-term lunar orbit. The Observer, from 60 miles above the moon's poles, would survey characteristics to provide a global context for the results from the Apollo program. o Space Infrared Telescope Facility Possible launch by shuttle in 1999, this is the 4th element of the Great Observatories program. A free-flying observatory with a lifetime of 5 to 10 years, it would observe new comets and other primitive bodies in the outer solar system, study cosmic birth formation of galaxies, stars and planets and distant infrared-emitting galaxies o Mars Rover Sample Return (MRSR) Robotics rover would return samples of Mars' atmosphere and surface to Earch for analysis. Possible launch dates: 1996 for imaging orbiter, 2001 for rover. o Fire and Ice Possible launch in 2001, will use a gravity assist flyby of Earth in 2003, and use a final gravity assist from Jupiter in 2005, where the probe will split into its Fire and Ice components: The Fire probe will journey into the Sun, taking measurements of our star's upper atmosphere until it is vaporized by the intense heat. The Ice probe will head out towards Pluto, reaching the tiny world for study by 2016. NEXT: FAQ #12/15 - Controversial questions ------------------------------ Date: 2 Sep 92 21:02:01 GMT From: SCOTT I CHASE Subject: What is the speed of light measured from? Newsgroups: sci.space In article <1992Sep2.154330.4348@relay.nswc.navy.mil>, bwallet@apssgi.nswc.navy.mil (Brad Wallet) writes... > >Bare with me a second because I am not a physicist. Why can't it be said >that the frame containing the Earth was moving relative to the traveller's >frame. If this is the case, the traveller would age more than the Earth. I have snipped the following item from the sci.physics FAQ. Enjoy. -Scott ******************************************************************************** Item 7. Special Relativistic Paradoxes - part (b) The Twin Paradox updated 17-AUG-1992 by SIC ---------------- original by Kurt Sonnenmoser A Short Story about Space Travel: Two twins, conveniently named A and B, both know the rules of Special Relativity. One of them, B, decides to travel out into space with a velocity near the speed of light for a time T, after which she returns to Earth. Meanwhile, her boring sister A sits at home posting to Usenet all day. When A finally comes home, what do the two sisters find? Special Relativity (SR) tells A that time was slowed down for the relativistic sister, B, so that upon her return to Earth, she knows that B will be younger than she is, which she suspects was the the ulterior motive of the trip from the start. But B sees things differently. She took the trip just to get away from the conspiracy theorists on Usenet, knowing full well that from her point of view, sitting in the spaceship, it would be her sister, A, who was travelling ultrarelativistically for the whole time, so that she would arrive home to find that A was much younger than she was. Unfortunate, but worth it just to get away for a while. What are we to conclude? Which twin is really younger? How can SR give two answers to the same question? How do we avoid this apparent paradox? Maybe twinning is not allowed in SR? Read on. Paradox Resolved: Much of the confusion surrounding the so-called Twin Paradox originates from the attempts to put the two twins into different frames --- without the useful concept of the proper time of a moving body. SR offers a conceptually very clear treatment of this problem. First chose _one_ specific inertial frame of reference; let's call it S. Second define the paths that A and B take, their so-called world lines. As an example, take (ct,0,0,0) as representing the world line of A, and (ct,f(t),0,0) as representing the world line of B (assuming that the the rest frame of the Earth was inertial). The meaning of the above notation is that at time t, A is at the spatial location (x1,x2,x3)=(0,0,0) and B is at (x1,x2,x3)=(f(t),0,0) --- always with respect to S. Let us now assume that A and B are at the same place at the time t1 and again at a later time t2, and that they both carry high-quality clocks which indicate zero at time t1. High quality in this context means that the precision of the clock is independent of acceleration. [In principle, a bunch of muons provides such a device (unit of time: half-life of their decay).] The correct expression for the time T such a clock will indicate at time t2 is the following [the second form is slightly less general than the first, but it's the good one for actual calculations]: t2 t2 _______________ / / / 2 | T = | d\tau = | dt \/ 1 - [v(t)/c] (1) / / t1 t1 where d\tau is the so-called proper-time interval, defined by 2 2 2 2 2 (c d\tau) = (c dt) - dx1 - dx2 - dx3 . Furthermore, d d v(t) = -- (x1(t), x2(t), x3(t)) = -- x(t) dt dt is the velocity vector of the moving object. The physical interpretation of the proper-time interval, namely that it is the amount the clock time will advance if the clock moves by dx during dt, arises from considering the inertial frame in which the clock is at rest at time t --- its so-called momentary rest frame (see the literature cited below). [Notice that this argument is only of a heuristic value, since one has to assume that the absolute value of the acceleration has no effect. The ultimate justification of this interpretation must come from experiment.] The integral in (1) can be difficult to evaluate, but certain important facts are immediately obvious. If the object is at rest with respect to S, one trivially obtains T = t2-t1. In all other cases, T must be strictly smaller than t2-t1, since the integrand is always less than or equal to unity. Conclusion: the traveling twin is younger. Furthermore, if she moves with constant velocity v most of the time (periods of acceleration short compared to the duration of the whole trip), T will approximately be given by ____________ / 2 | (t2-t1) \/ 1 - [v/c] . (2) The last expression is exact for a round trip (e.g. a circle) with constant velocity v. [At the times t1 and t2, twin B flies past twin A and they compare their clocks.] Now the big deal with SR, in the present context, is that T (or d\tau, respectively) is a so-called Lorentz scalar. In other words, its value does not depend on the choice of S. If we Lorentz transform the coordinates of the world lines of the twins to another inertial frame S', we will get the same result for T in S' as in S. This is a mathematical fact. It shows that the situation of the traveling twins cannot possibly lead to a paradox _within_ the framework of SR. It could at most be in conflict with experimental results, which is also not the case. Of course the situation of the two twins is not symmetric, although one might be tempted by expression (2) to think the opposite. Twin A is at rest in one and the same inertial frame for all times, whereas twin B is not. [Formula (1) does not hold in an accelerated frame.] This breaks the apparent symmetry of the two situations, and provides the clearest nonmathematical hint that one twin will in fact be younger than the other at the end of the trip. To figure out *which* twin is the younger one, use the formulae above in a frame in which they are valid, and you will find that B is in fact younger, despite his expectations. It is sometimes claimed that one has to resort to General Relativity in order to "resolve" the Twin "Paradox". This is not true. In flat, or nearly flat space-time (no strong gravity), SR is completely sufficient, and it has also no problem with world lines corresponding to accelerated motion. References: Taylor and Wheeler, _Spacetime Physics_ (An *excellent* discussion) Goldstein, _Classical Mechanics_, 2nd edition, Chap.7 -------------------- Scott I. Chase "The question seems to be of such a character SICHASE@CSA2.LBL.GOV that if I should come to life after my death and some mathematician were to tell me that it had been definitely settled, I think I would immediately drop dead again." - Vandiver ------------------------------ Date: 3 Sep 92 03:01:29 GMT From: Patrick Chester Subject: Who went to Rio Newsgroups: sci.space I'll make this brief. I just would like to know if any spaceflight advocacy groups like the L-5 Society or the Lunar Society made it to the Earth Summit in Rio last June. I was hoping someone tried to inject some other views on saving the environment there (like moving some industry off Earth and getting resources from the asteroids, etc.) Just wondering. ------------------------------ Date: Thu, 3 Sep 1992 06:53:18 GMT From: Phew Subject: With telepresence, who needs people in Earth orbit? Newsgroups: sci.space arnold@clipper.ingr.com (Roger Arnold) writes: >It's easy to make telepresence look bad or difficult if you can get away >with discussing it in terms of the capabilities of autonomous robots. >I see telepresence not as competition to manned space activity, but >as a bridge to the level of space activity that will be necessary to >bring costs down and make it worth building real space stations. A >teleoperated research facility in low earth orbit would find no short- >age of commercial customers. If they only had to pay for delivery of >small quantities of material and a share in amortization of the equip- >ment in orbit, it would be a bargain. >Obviously, there are limits to what you can do with telepresence from >earth. That doesn't mean that what you *can* do isn't worth doing. I fully agree that telepresence has validity in a large number of applications. What I would object to is development of telepresence as the *sole* means of presence in space. Telepresence and robotics may be the fastest way to make affordable space technology, but depending upon them entirely could lead to problems if permanent human presence is ever required/desired on the Moon, Mars or beyond. It may require a total redevelopment of the technology to date if future human presence is *not* envisaged now. An example of how hard it is to replace existing technologies is current household refridgeration. These are largely based on CFCs and will have to be replaced due to ozone depletion. The current CFC replacements are also not safe, and it may take a total rethink of the technology to get something that works properly. The fridge example was the result of lack of scientific understanding, not because we didn't understanding ourselves, or our objectives. If it is Human-Kinds goal to have a permanent presence in space, then the technology to achieve this must be developed, starting now. Patrick Hew 1st Year Science/ Engineering University of Western Australia ------------------------------ End of Space Digest Volume 15 : Issue 163 ------------------------------