Marsbugs: The Electronic Astrobiology Newsletter Volume 10, Number 48, 9 December 2003 Editor/Publisher: David J. Thomas, Ph.D., Science Division, Lyon College, Batesville, Arkansas 72503-2317, USA. dthomas@lyon.edu Marsbugs is published on a weekly to monthly basis as warranted by the number of articles and announcements. Copyright of this compilation exists with the editor, except for specific articles, in which instance copyright exists with the author/authors. The editor does not condone "spamming" of subscribers. Readers would appreciate it if others would not send unsolicited e-mail using the Marsbugs mailing lists. Persons who have information that may be of interest to subscribers of Marsbugs should send that information to the editor. E-mail subscriptions are free, and may be obtained by contacting the editor. Information concerning the scope of this newsletter, subscription formats and availability of back-issues is available from the Marsbugs web page at http://www.lyon.edu/projects/marsbugs/. [http://www.esrin.esa.int:80/export/esaCP/SEMN3GUZJND_index_0.html] This picture was taken on 1 December 2003 from ESA's Mars Express spacecraft by the High Resolution Stereo Camera (HRSC) under the responsibility of the Principal Investigator Professor Gerhard Neukum. It was processed by DLR Institute for Planetary Research, also involved in the development of the camera, and by the Freie Universität Berlin. This picture shows planet Mars as seen from a distance of about 5.5 million kilometers. This is a very unusual view of Mars because the planet is illuminated in a way never seen from Earth. The Sun shines on part of the western hemisphere, but more than a third of the martian disc lies in the dark. The dark features at the top are part of the northern lowlands of Mars, where oceans possibly existed thousands of millions of years ago. Image credit: ESA. ________________________________________________________________________ CONTENTS 1) METEOR LIKELY CAUSED EARTH'S GREATEST EXTINCTION EVENT University of California, Santa Barbara release 2) MEMBRANES ON MARS By Karen Miller 3) WHY DON'T WE JUST GO THERE? A TEACHABLE MOMENT By Edna DeVore 4) MAKE YOUR OWN MARS EXPRESS ESA release 5) ARECIBO DIARIES: THE BIRTHDAY PRESENT By Peter Backus 6) ODYSSEY STUDIES CHANGING WEATHER AND CLIMATE ON MARS NASA/JPL release 2003-165 7) THE BIG CRUNCH: INTERVIEW WITH DAN WERTHIMER From Astrobiology Magazine 8) 10 REASONS TO PUT HUMANS BACK ON THE MOON By Robert Roy Britt 9) NASA LEARNING TO MONITOR CORAL REEF HEALTH FROM THE SKY NASA/ARC release 03-101AR 10) NEW ADDITIONS TO THE ASTROBIOLOGY INDEX By David J. Thomas 11) CASSINI SIGNIFICANT EVENTS NASA/JPL release 12) MARS GLOBAL SURVEYOR IMAGES NASA/JPL/MSSS release 13) MARS ODYSSEY THEMIS IMAGES NASA/JPL/ASU release 14) STARDUST STATUS REPORT NASA/JPL release ________________________________________________________________________ METEOR LIKELY CAUSED EARTH'S GREATEST EXTINCTION EVENT University of California, Santa Barbara release 1 December 2003 The "Great Dying," a time of earth's greatest number of extinctions, appears to have been caused by the impact of a large meteor, according to a research team that includes Luann Becker, a scientist with the Institute for Crustal Studies in the Department of Geology at the University of California, Santa Barbara. The theory, recently published by the team in the journal Science (November 21, 2003), explains that this extinction event, which occurred approximately 251 million years ago, is much earlier than the demise of the dinosaurs, which is estimated at approximately 65 million years ago and is also believed to have been caused by a large meteor impact. The evidence is the most convincing yet for an impact at the "end- Permian," a time commonly referred to as "The Great Dying," when life was nearly erased from the earth, explained Becker. She is currently working in Antarctica with a team searching for more "impact tracers," the geological markers that show evidence of large meteors hitting the earth. Becker has made several research trips to Antarctica and in July 2001 she received the National Science Foundation Antarctic Service Medal. Her article "Repeated Blows," published in the March 2002 issue of Scientific American, describes the evidence for many past collisions with asteroids and how geologists are able to find the evidence for these collisions and to date them. In her overview she states: "About 60 meteorites five or more kilometers across have hit the earth in the past 600 million years. The smallest ones would have carved craters some 95 kilometers wide. "Most scientists agree that one such impact did in the dinosaurs, but evidence for large collisions coincident with other mass extinctions remained elusive--until recently. "Researchers are now discovering hints of ancient impacts at sites marking history's top five mass extinctions, the worst of which eliminated 90 percent of all living species." Becker's current research at the Graphite Peak in the Central Transantarctic Mountains, Antarctica, described in the recent Science article, has revealed several meteoritic fragments, metallic grains, in a thin claystone "breccia" layer. Becker and the research team believe this to be strong evidence for a large impact that appears to have triggered the Great Dying. Breccia is ejected debris that resettled in a layer of sediment. The metallic grains also appear in the same layer (end-Permian) in Meishan, southern China. They also resemble grains found in the same strata in Sasayama, Japan. (The earth was a single continent at the time of the impact.) The team also found "shocked quartz" in this same layer in the Graphite Peak. In the Scientific American article Becker explained, "Few earthly circumstances have the power to disfigure quartz, which is a highly stable mineral even at high temperatures and pressures deep inside the earth's crust." Quartz can be fractured by extreme volcanic activity, however, only in one direction. Shocked quartz is fractured in several directions and is therefore believed to be a good tracer for the impact of a meteor. The researchers are somewhat surprised that they have not found the strong presence of the mineral iridium in the Graphite Peak work. In an e-mail from Antarctica Becker stated, "Interestingly, we do not see a strong iridium anomaly (the impact tracer that marks the Cretaceous- Tertiary boundary or the dinosaur extinction event)." As she explained in Scientific American, "The first impact tracer linked to a severe mass extinction was an unearthly concentration of iridium, an element that is rare in rocks on our planet's surface but abundant in many meteorites... From this iridium discovery (in 1980) came the landmark hypothesis that a giant impact ended the reign of the dinosaurs--and that such events may well be associated with other severe mass extinctions over the past 600 million years." The discovery was strongly debated around the world and scrutinized by geologists. The increased attention brought about the discovery of more impact tracers, including extraterrestrial fullerenes found in the Graphite Peak boundary layer. These tracers are carbon molecules called fullerenes for their soccer-ball shape. They trap extraterrestrial gases in space and travel to the earth in the meteor. The team concludes the Science article by saying, "These observations lead us to believe that continued research on such materials from additional Permian-Triassic boundary samples will finally lead to a resolution of the long-sought and contentious issue of a catastrophic collision of a celestial body with the Earth at the end-Permian. In light of the new evidence presented here, this is a reasonable interpretation of the global extinction event at the Permian-Triassic boundary." Read the original news release at http://www.instadv.ucsb.edu/release/Display.aspx?PKey=1073. Additional articles on this subject are available at: http://www.astrobio.net/news/article697.html http://www.sciencemag.org/cgi/content/abstract/302/5649/1388 ________________________________________________________________________ MEMBRANES ON MARS By Karen Miller From NASA Science News 3 December 2003 The ideal technology for space travel would be simple, robust, reliable, lightweight, and volumetrically efficient. It would have no moving parts, which would make it less likely to break. It would be a passive technology, not requiring any energy from the outside. It would be small. It would be light. An ideal technology for space, says chemical engineer Doug Way, is the membrane. Well, OK, membranes can't do everything. Membranes won't boost us into space. And they won't carry us to Mars. But membranes could solve some of the problems of traveling there. And once we arrive, they could help us get back. Basically, membranes are a semi-permeable barrier. They're like a wall, except that gases, and even liquids, can seep through them. But--here's the key point--different molecules move through membranes at different rates. Membranes can therefore be used to sort things out, separating one type of molecule from another. Doug Way of the Colorado School of Mines and Lockheed engineer Larry Mason are working on a NASA-funded project that uses membranes to help produce rocket fuel from the martian atmosphere. The principle is simple. The martian atmosphere is 95% carbon dioxide (CO2). Using membranes, explorers could extract some of that CO2, which when mixed with hydrogen and then heated yields methane--a useful propellant for rockets or rovers. Water is a byproduct of this type of methane production, called the Sabatier process (discovered by the French chemist Paul Sabatier in the nineteenth century). What's more, water can be electrolyzed into oxygen, for breathing, and hydrogen, which can be used to produce another round of methane. Although the martian atmosphere is almost pure CO2, it's not pure enough for the Sabatier process. Carbon dioxide must be separated from the other atmospheric gases before it's processed. Otherwise unused gases-- mostly nitrogen and argon--build up, and will eventually keep the procedure from working. Way and Mason are developing a membrane that will separate out CO2. The specialized polymers that make up these membranes, some of which were developed at the Idaho National Environmental and Engineering Laboratory, are engineered to increase carbon dioxide solubility. "We add in groups of molecules that are polar--they carry an electric charge," says Way. Because carbon dioxide molecules are also polar, they're attracted to charged groups in the membrane. The membranes are tested in a special chamber that simulates the martian environment, explains Larry Mason. The device, which is about a meter high, is divided into two compartments. One contains a Mars-like atmosphere, and the other side contains a vacuum. They're separated by a membrane that's about one square inch in surface area. A mass spectrometer measures how easily each gas moves into the vacuum side. "In the best [membrane] material we've found," says Way, "at martian conditions, CO2 was transferred across the membrane about 50 times faster than nitrogen." "Right now," adds Mason, "we're screening different candidate materials to find the ones that permeate CO2 the best. Once we find that, we can concentrate on getting enough through in an appropriate amount of time, by changing the amount of area, packaging it, and so on." The researchers want to design a device that produces a gas that's 99.8 percent CO2 at a rate of 2.5 liters per minute. To do that, Way says, will require quite a bit of membrane. Although the membrane is very thin--about 25 microns, one-quarter of the diameter of a strand of hair- -it will probably need to be about 300 square feet in area, the size of a small room. All that will have to fit into a package of about 1 square foot. But a membrane that separates CO2 from other gases can do more than provide the raw material for rocket fuel. "This is fundamental technology," says Mason. "It's got all kinds of uses." It could, for example, be used to filter air on the space station or on a spaceship bound for Mars. Carbon dioxide, which is a waste product of our metabolism, must continually be removed from the atmosphere of self- contained spacecraft. Membranes that are permeable only to carbon dioxide would be perfect, says Mason. "The CO2 would just passively go through the membrane into a holding chamber--or out into space. Oxygen and other gases would stay intact inside the habitat." These membranes could potentially help slow global greenhouse warming, too. "There's some thought," says Mason, "that a membrane could be used in extracting CO2 from factory smoke stacks--reducing the amount of carbon dioxide that's dumped into the atmosphere." Such an application still lies in the future, he says. "The biggest potential Earth-application," adds Way, "is the removal of CO2 from natural gas. CO2 is the most common contaminant in natural gas besides water vapor. Membrane separations are one of the primary processes used to filter natural gas so that it meets pipeline specifications of less than 2% CO2." This is a big deal because "the natural gas industry is huge--more than 100 billion dollars per year in retail value," according to Way. To Mason, "the most exciting part of this technology is the fact that it may leverage us to actually go to Mars and live and work there someday." And, in the meantime, there are plenty of uses for it right here on Earth. Read the original article at http://science.nasa.gov/headlines/y2003/03dec_membranes.htm. An additional article on this subject is available at http://www.spacedaily.com/news/mars-general-03u.html. ________________________________________________________________________ WHY DON'T WE JUST GO THERE? A TEACHABLE MOMENT By Edna DeVore From Space.com 4 December 2003 Captain Picard and his crew captured the minds and hearts of many viewers as they explored the universe visiting extrasolar worlds and meeting exotic aliens--all without doing harm. Warp speed made it possible. Ah, to travel at warp speed. Doesn't everyone want to be able to command a space ship to leap across the galaxy, to issue the order: "Make it so!" I sure do, but so far, no one beyond Hollywood has figured out how. There may be numerous intelligent civilizations on planets throughout our galaxy. That's the hypothesis that drives SETI research. We seek evidence of extraterrestrial technology using optical and radio telescopes to search for signals that emanate from other civilized worlds. These places are far, far away. But, when you discuss the search with school children, often they simply ask, "Why don't we just go there?" Often, the best teaching and learning occurs when a good question is asked, and explored. The easy reply is that "it's too far away." What does "too far away" mean to a sixth grade student who imagines standing on the deck of the Enterprise, searching for intelligent life on distant worlds? Her parents may have said the same thing about going to Disneyland for the weekend. In both cases, the travel time doesn't merit the trip. So, can the issues around space travel to distant worlds be made "real" or at least comprehensible when she asks, "Why don't we just go there?" Read the full article at http://www.space.com/searchforlife/seti_devore_distance_031204.html. ________________________________________________________________________ MAKE YOUR OWN MARS EXPRESS ESA release 4 December 2003 Throughout Europe, over a thousand people, both engineers and scientists, have been involved in the development and building of Mars Express. However, only one person is needed to build a model of Mars Express, and that's you! The real Mars Express spacecraft weighs 1200 kilograms and measures 1.5 by 1.8 by 1.4 meters (excluding solar panels). This is probably far too big for your study or bedroom, so we have made our model a bit smaller... Download your own blueprints to make a model of the first European spacecraft to visit another planet! http://esamultimedia.esa.int/images/spcs/goodies/models/mars_express_mod el_kit.pdf More fascinating model plans are available at http://www.esa.int/esaSC/SEMEO5T1VED_index_0.html. ________________________________________________________________________ ARECIBO DIARIES: THE BIRTHDAY PRESENT By Peter Backus From Space.com 8 December 2003 In the words of Indiana Jones, "It's not the years, it's the mileage." At 6:29 Atlantic Standard Time this morning, I completed fifty-one orbits of our local star. So, today is my orbital anniversary. In that time (discounting the Earth's diurnal rotation), I've traveled nearly 30 billion miles while orbiting the Sun. My colleague, Mike Davis completed his sixty-fifth orbit two days ago. He's logged eight billion more miles, which leaves me puzzling over why it is that he consistently manages to beat me when we race up the stairs to our cabins. On the grand timescale of the cosmos, I can feel much younger. Since 1952, the year of my birth, our Solar System has completed a mere 0.2 millionth of one orbit around the galactic center (a complete orbit is called a Galactic Year). However you measure the time, I feel fortunate to be where I am today because I wanted to be here for as long as I can remember. On another orbital anniversary four decades ago, I received a very special present- a children's science book that I've never forgotten. I can still picture the cover of the book: gray lines and colorful, bright pictures on a black background. The pictures represented different fields of science, and inside were sections on each: geology, biology, chemistry, physics, medicine, and of course, astronomy. I enjoyed all of it-even the gory pictures of brain surgery. The Astronomy section however, especially captivated me, with its pictures of galaxies and nebulae. And then, there were the pictures of telescopes! It was in that wonderful book that I first saw the newly constructed Arecibo 1,000-foot antenna. Read the full article at http://www.space.com/searchforlife/seti_arecibo_backus_031208.html. ________________________________________________________________________ ODYSSEY STUDIES CHANGING WEATHER AND CLIMATE ON MARS NASA/JPL release 2003-165 8 December 2003 Mars may be going through a period of climate change, new findings from NASA's Mars Odyssey orbiter suggest. Odyssey has been mapping the distribution of materials on and near Mars' surface since early 2002, nearly a full annual cycle on Mars. Besides tracking seasonal changes, such as the advance and retreat of polar dry ice, the orbiter is returning evidence useful for learning about longer-term dynamics. The amount of frozen water near the surface in some relatively warm low- latitude regions on both sides of Mars' equator appears too great to be in equilibrium with the atmosphere under current climatic conditions, said Dr. William Feldman of Los Alamos National Laboratory, NM. He is the lead scientist for an Odyssey instrument that assesses water content indirectly through measurements of neutron emissions. "One explanation could be that Mars is just coming out of an ice age," Feldman said. "In some low-latitude areas, the ice has already dissipated. In others, that process is slower and hasn't reached an equilibrium yet. Those areas are like the patches of snow you sometimes see persisting in protected spots long after the last snowfall of the winter." Frozen water makes up as much as 10 percent of the top meter (three feet) of surface material in some regions close to the equator. Dust deposits may be covering and insulating the lingering ice, Feldman said. He and other Odyssey scientists described their recent findings today at the fall meeting of the American Geophysical Union in San Francisco. "Odyssey is giving us indications of recent global climate change in Mars," said Dr. Jeffrey Plaut, project scientist for the mission at NASA's Jet Propulsion Laboratory, Pasadena, CA. High latitude regions of Mars have layers with differing ice content within the top half meter (20 inches) or so of the surface, researchers conclude from mapping of hydrogen abundance based on gamma-ray emissions. "A model that fits the data has three layers near the surface," said Dr. William Boynton of the University of Arizona, Tucson, team leader for the gamma-ray spectrometer instrument on Odyssey. "The very top layer would be dry, with no ice. The next layer would contain ice in the pore spaces between grains of soil. Beneath that would be a very ice-rich layer, 60 to nearly 100 percent water ice." Boynton interprets the iciest layer as a deposit of snow or frost, mixed with a little windblown dust, from a cold-climate era. The middle layer could be the result of changes brought in a warmer era. The ice down to a certain depth dissipates into the atmosphere. The dust left behind collapses into a soil layer with limited pore space for returning ice. Information from the gamma-ray spectrometer alone is not enough to tell how recently the climate changed from colder to warmer, but an estimated range might come from collaborations with climate modelers, Boynton said. Other Odyssey instruments are providing other pieces of the puzzle. Images from the orbiter's camera system have been combined into the highest resolution complete map ever made of Mars' south polar region. "We can now accurately count craters in the layered materials of the polar regions to get an idea how old they are," said Dr. Phil Christensen of Arizona State University, Tempe, principal investigator for the camera system. Temperature information from the camera system's infrared imaging has produced a surprise about dark patches that dot bright expanses of seasonal carbon-dioxide ice. "Those dark features look like places where the ice has gone away, but thermal infrared maps show that even the dark areas have temperatures so low they must be carbon-dioxide ice." Christensen said. "One possibility is that the ice is clear in these areas and we're seeing down through the ice to features underneath." Odyssey's high-energy neutron detector continues to monitor seasonal changes in the amount of carbon-dioxide ice deposited in polar regions, allowing tests of atmosphere-circulation models, said Dr. Igor Mitrofanov of the Institute for Space Research, Moscow, Russia. Measurements by an instrument for monitoring the radiation environment at Mars show the level of radiation hazard that Mars-bound astronauts might face, including levels during a period of unusually intense solar activity, said Dr. Cary Zeitlin of the National Space Biomedical Research Institute, Houston. JPL manages Mars Odyssey for NASA's Office of Space Science, Washington. Investigators at Arizona State University, Tempe; University of Arizona, Tucson; NASA's Johnson Space Center, Houston; the Russian Aviation and Space Agency, Moscow; and Los Alamos National Laboratory, Los Alamos, NM, built and operate Odyssey science instruments. Information about the mission is available on the Internet at http://mars.jpl.nasa.gov/odyssey. Contacts: Guy Webster Jet Propulsion Laboratory, Pasadena, CA Phone: 818-354-6278 Donald Savage NASA Headquarters, Washington, DC Phone: 202-358-1727 Additional articles on this subject are available at: http://www.space.com/scienceastronomy/mars_ice-age_031208.html http://www.spacedaily.com/news/mars-odyssey-03b.html http://spaceflightnow.com/news/n0312/08odyssey/ ________________________________________________________________________ THE BIG CRUNCH: INTERVIEW WITH DAN WERTHIMER From Astrobiology Magazine 8 December 2003 Cosmologists model the end of the universe as The Big Crunch-they roughly reverse the simulations of how the expansive Big Bang might have spawned all the stars and planets. But for those interested in what is happening between the bang and the crunch on that uncountable number of planets, the big crunch can mean something different. The scientists who built the world's largest supercomputer have a daily task of sorting the radio noise that showers our little corner of the galaxy. For this number crunching, their network can be as close as your own home. No matter how much time you may think you are spending on your computer today, it is likely you are unable to overload its true capabilities. The average personal computer is running in second gear most of the time. Whatever is happening--whether surfing the internet or answering an email--you are not likely taxing the processor (CPU cycles) or its spare bandwidth. This "overhang" is exactly the spare capacity that innovative scientists have figured out how to tap into: what if millions of PCs could be linked together in parallel to finish a job, one that normally would require a supercomputer and its mainframe price in the hundreds of millions of dollars? The concept is called distributed computing. The most well-known implementation is a massive search of the night sky for intelligent radio signals, the SETI@home project. That has been one bold dream of the Berkeley team behind the SETI@home screensaver program. The project runs the world's largest virtual supercomputer. In rough terms, if the planet's total computer resources were tallied, the SETI@home volunteers contribute about one out of every thousand processing cycle potentially available everywhere. But the volunteer network is not just about crunching data. Arguably, the underlying screensaver program itself is the most widely distributed software in daily use ever conceived [1]--other than maybe web browsers- -given that the screensaver is most active when the rest of the unused programs are idle. In a very practical way, SETI@home has changed the world's perception of what can be done while the rest of the world, and their computers, are asleep. After more than five years running SETI@home, Werthimer, the Chief Scientist, and Anderson, the Project Leader, may appear not to need much sleep, given that they have tied together the entire world (226 countries) in a way that even the most optimistic futurists would have missed. But seamlessly changing time zones is something computers are good at. On a per capita basis, other than North America and Scandanavia, the most active region for contributing to SETI@home is the most remote: Antarctica. If jumping 226 national borders isn't challenging enough, moving data back and forth to 4.7 million individual computers is something you have to be a little audacious to even dream about. Most network would wilt at the assignment. For this task at Berkeley, the home server is aptly named "SAGAN", and goes well beyond handling Carl Sagan's hallmark equivalent by having powered "billions and billions" of jobs. As a radio astronomer, Werthimer is perhaps trained from graduate school to see the passage of time not in cyclical sunrises and sunsets--but in his own unique data units. Werthimer's cycles are a bit different. Each day for the SETI@home network offers the equivalent to a thousand years of donated computing time. Each signal is listened to on billions of channels. Each day, the network is touching the equivalent population of what might fill up the Rose Bowl's 100,000 seating capacity--more than six times over. Working together with a radio carriage mounted above the world's largest radio telescope, Werthimer has managed to cover about ninety-five percent of the available sky from that location (Arecibo, Puerto Rico). The giant Arecibo dish spans 305 meters (more than three football fields across) in the Puerto Rican woodlands. To fill in any holes in their sky map, observations from the Southern Hemisphere are currently part of the Southern SERENDIP, a sky survey that covers stars unviewable from Arecibo. The team is also in the early planning stages with the Australian-based Parkes telescope in what is called the Southern SETI@home. [Among Parkes' many noteworthy science contributions, the telescope was the star of the Australian movie, "The Dish", since it proved the critical link that brought to the world the live images from the first moonwalk of Neil Armstrong. Without Parkes, one of the most stunning events of the century would have been just fuzzy TV static]. The first lesson from those listening for potentially intelligent radio signals may well be the most obvious one: the universe is very big place. The bad news is this gives a lot of places to point a receiver; that is the good news too, at least as far as considering the possible candidates for where a civilization might advance far enough technologically to communicate with our tiny corner of the galaxy. The SETI@home database has logged about 100 million candidate signals. About two hundred have been filtered into a bin labeled "interesting". Ultimately, Werthimer is the radio astronomer who knows what is interesting or not. Astrobiology Magazine had the opportunity to talk with Dr. Werthimer about what it takes to survive the big crunch. Astrobiology Magazine (AM): Remarkably, a single modern desktop PC today is more powerful than a 15-year old supercomputer. So in a way, by patching together a volunteer network like SETI@home, that is the best way--or even the only way--to keep current in today's supercomputing. Was an initial target to get several hundred thousand people participating with computers--to perhaps a peak of a million users? Dan Werthimer (DW): When we launched SETI@home, we thought we'd be lucky to get ten thousand people to participate. SETI@home is now our planet's largest supercomputer, averaging 60 teraflops, thanks to 4.7 million SETI@home volunteers in 226 countries. [Editorial note: Teraflops refers to speed, or sometimes computer power. For benchmarks, the term "FLOPS" means floating point operations per second--an approximate measure of a computer's processing speed. Teraflops refer to a trillion (1012) such operations per second. On a relative scale it is interesting that by comparison, the combined calculating power of all the computers on the planet would only amount to several thousand teraflops, also a unit called a petaflop, making by this coarse measure, the volunteer SETI@home network very approximately 0.1% of the world total]. DW: The volunteers contribute 1000 years of computing time daily. So far we've recorded and analyzed about 52 Tbytes (terabytes, or one trillion (1012) bytes) of data on 1,500 tapes. [Editorial note: Terabytes refer to information storage. For comparison, a typical video store contains about 8 terabytes of video. The books in the largest library in the world, the U.S. Library of Congress, contain about 20 terabytes of text, making the SETI@home storage more than two and half times greater than the planet's printed volumes]. DW: Our database currently stores about 100 million candidate signals, and we've dubbed about 200 of these candidates "interesting". AM: To allow other science projects to access the unique SETI@home architecture, there is a new plan to roll out a prototype expansion of the screensavers, called BOINC. What is the schedule for rolling out BOINC (Berkeley Open Infrastructure for Network Computing)? DW: We are beta-testing BOINC now and hope to have it working well towards the end of the year. BOINC allows volunteers to participate in a number of different projects; volunteers will be able to specify what fraction of their spare CPU cycles should go toward SETI@home (including SETI@home candidate followup with the higher resolution 8 bit data), Astropulse (searching for primordial black holes or radio pulses from ET), Protein Folding (Folding@home at Stanford), Climate Modeling (Oxford, climateprediction.net) and hopefully other projects as well. BOINC is developed by my colleague Dr. David Anderson. David is a computer scientist and an expert at distributed computing. David developed the SETI@home code and directs both the SETI@home and BOINC projects. AM: The Planetary Society sponsored some of the early 1998 work to create the world's largest virtual supercomputer, based on calls with you and David Anderson. From the outset of SETI@home, what was common atmosphere at that time about its ultimate size and workability-- audacious, outlandish or quixotic? DW: Most people were skeptical we could make it work, or that anybody would sign up. The Planetary Society was the only group willing to provide seed funding, take the risk, and try something unconventional. AM: What role did Ann Druyan and the Carl Sagan Fund for the Future have to play in launching what must have seemed impossible at the time? DW: Carl was very excited about SETI@home in the early stages, but unfortunately he never got to see SETI@home grow. We named SETI@home's server "SAGAN" in Carl's honor. SAGAN "communicates" daily to millions of participants in a global science project. The real Sagan communicated science to over 500 million people. Carl's wife and collaborator, Ann Druyan, has helped enormously by raising crucial funding for SETI@home. AM: I have heard the original founding group feels that the goal of SETI--discovery of an intelligent signal--was the unique draw, what got so many people to join in, along with the surprisingly competitive aspects of exactly who could provide the most data units. That became a kind of attractive sport for serious users. Do you think a science project in another field than SETI would have had such a successful roll-out? DW: Other distributed computing projects have attracted tens of thousands of volunteers. But SETI@home is the largest; almost all earthlings are interested in the question "Are We Alone?"; people are eager to help. AM: How did this draw of users competing, this competition itself, become so prominent? Some clubs have formed with up to nearly 6,000 people pooling big computers, with single clubs doing the equivalent of tens of thousands of years of computing time. Was all that expected, or did it just evolve from the usage patterns of the early adopters? DW: We didn't expect friendly competition to lead to such craziness. You can buy work units on eBay--for merely a few hundred dollars, an eBay seller will transfer their work units to your account, so you'll receive the credit and your name will rise close to the top of the lists on the SETI@home web site. AM: Let's talk about the SETI search itself--where all that data is coming from. Currently the Berkeley home server is sending out and receiving back radio data that was originally collected at Arecibo, in Puerto Rico--the world record-holder for single dish size. That is like our planet's "biggest ear", listening for signals. So for collecting all the radio data that SETI@home is crunching, what percentage of the night sky has been covered from this location-- to be subsequently analyzed by SETI@home? DW: The Arecibo telescope can "see" about a third of the whole sky (the dish covers declinations from -2 to +38 degrees). We've covered 95% of that sky (or about 30% of the whole sky). We've observed most beams several times. It's important to observe the same point in the sky several times because extraterrestrial transmitters might not be on or be visible all the time, and many of our candidate detection algorithms require a signal be repeatable. AM: Will the SETI@home computers process any future radio data not from the Arecibo Observatory? DW: Perhaps, but we are more excited about collecting and analyzing data from the upcoming multi-beam receiver at Arecibo--there will be spectacular all-sky surveys using this new 7 beam receiver starting in 2005. And we are trying to raise funds to work with our Australian colleagues to collect data for "Southern SETI@home" at the Parkes telescope. AM: With private donors, the SETI Institute and Berkeley are constructing a telescope that is kind of distributed, like the screensavers, in that it will be an array of 350 commercial satellite dishes--individual 20-foot antennae--that combine their reception to make a huge telescope grid. That is called the Allen Telescope Array planned for 2005 or beyond, correct? DW: The Allen Telescope Array (ATA) is a giant telescope made from hundreds of small dishes; it's a joint project of the SETI Institute and the University of California, Berkeley. It's terrific for targetted SETI searches, and is paving the way for future giant telescopes. AM: Berkeley has been involved since the beginning of the SETI project called by the acronym, SERENDIP, for the "Search for Extraterrestrial Radio Emissions from Nearby Developed Intelligent Populations". The project is the world's only "piggyback" SETI system, operating alongside simultaneously conducted conventional radio astronomy observations. How is SERENDIP part of the giant 305-meter (1000-foot) Arecibo radio dish? Is this a continuous data feed that is selective for the radio frequencies that are either most accessible or of most interest to SETI research? DW: Most observers are lucky to get two days a year on the world's largest radio telescope, but SERENDIP has a dedicated feed and receiver on Arecibo's carriage house, enabling us to conduct SETI observations 24 hours a day, year round. Observing at the same time other scientists are using the telescope. That is what makes the SERENDIP and SETI@home searches so powerful. We developed this "Piggyback SETI" technique in the late 1970's. AM: To be clear, one needs to tune in on a SETI source, just like you can tune through the various radio bands--AM, FM, short-wave, ham, police, weather, etc.--so where exactly on the radio dial does modern SETI and SERENDIP tune in? DW: The dedicated feed/receiver at Arecibo covers a 100 megahertz (MHz, one million Hertz, or vibration cycles per second) band centered at 1420 MHz (the Hydrogen line). SERENDIP analyzes the full 100 megahertz (MHz) band available from the receiver. [Editorial note: This SETI radio search involves a frequency that is relatively quiet, between 1000 and 10,000 MHz--just above the frequencies used by electronic pagers and some wireless cell phones at 900 MHz. The most abundant molecules are hydrogen, either neutral gas at 1420 MHz or combined with oxygen at 1640 MHz. In the spectrum of background that rains on our planet from interstellar space, this quiet region is called the "water-hole", because water molecules (necessary for life as we know it terrestrially), has this vibration. Modern SETI efforts began with a paper written by physicists Giuseppe Cocconi and Philip Morrison. They published in the science press in 1959. Cocconi and Morrison suggested that the microwave frequencies between 1000 and 10,000 megahertz would be best suited for interstellar communications.] AM: What is the primary challenge for SETI researchers today? DW: Earthlings are just beginning to learn how to hunt for ET. We can only observe small parts of electromagnetic spectrum, or small parts of the sky, and we are limited in search sensitivity and signals types. But capabilities are growing exponentially--we used to listen to 100 channels at once (SERENDIP I); now we listen to 168 million channels at once (SERENDIP IV), and we are designing 2 and 20 billion channel spectrometers. AM: So is it better to look on many narrowly tuned channels, or a broad spectrum? In your experience, technically, is the assumption of another civilization sending a signal as some kind of a transmission distinct from natural radio background (noise), is that a better bet than the particular choices of single, narrow beacon-like transmission? DW: It's hard to predict what ET might be doing. My guess is that it's more likely we'll discover an artifact of a civilization's technology rather than a signal directed to us for the purpose of interstellar communication--perhaps we'll discover navigational beacon, an asteroid radar system, radio signals leaking off their planet, or something completely unexpected. We should be looking in the visible, infrared and radio for a variety of signal types, and mining data bases from other astronomy surveys, on the lookout for something unusual. If you had asked me 100 years ago what to look for, I might have said smoke signals. Our Berkeley SETI group is conducting five different searches for radio and optical signals, both pulsed and continuous. The more variety, the better the chances of finding ET. AM: So is it a pulse or kind of siren that scores well in SETI searches? DW: SETI@home covers spectral resolutions from 0.07 Hz to 1 KHz, so we can detect pulses and broad band signals. AM: For instance, what about signal drift? What happens in cases when both the receiving and the transmitting planet are also moving, if that causes multiple, unknown Doppler drifts? Is this an uncertainty in what is the maximum achievable resolution? One problem with massive Fast- Fourier-Transforms is bin-size (say, discrete 1 hertz (Hz) wide for sensitivity) but those narrow signals have only a six second integration time because the Earth's motion causes a doppler shift out of this signal. DW: Because of the massive computing power contributed by the SETI@home volunteers, SETI@home is able to conduct a sensitive search for drifting coherent signals from -50 Hz/sec to +50 Hz/sec (eg: transmitters on the surface of planets or in orbit around planets). AM: What do you think would make the biggest difference for technically upgrading the search? DW: No SETI experimenter has searched for short radio pulses before, because it's extremely computationally intensive. We are launching a new distributed computing search, "Astropulse", which searches for dispersed radio pulses as narrow as 400 nanoseconds. Such pulses might come from extraterrestrial civilizations; but also might come from primordial black holes. Steven Hawking figured out that black holes evaporate; when the they finally reach zero mass, the black holes are likely to give off a radio pulse. Astropulse will mine the 50 Terabytes of SETI@home data to search for such pulses. [Editorial note: This type of pulsed signal is different from those which would be caught by SETI@home. Since the pulses are so fast, they are broad-band signals. Such pulses travelling through the interstellar medium (the thin gas which fills the space between stars in our galaxy) become "dispersed," or stretched out in time. SETI searches can correct for this effect with a specialized algorithm (known as "coherent de- dispersion"), but it is very computation intensive, which is why this is a good distributed computing project.] AM: Do you have a personal favorite for what you have seen in seti@home data as a false positive? Something like the Ohio State "WOW" signal that meets all the detection criteria but turned out to have a mundane cause? DW: All the powerful radio signals have turned out to be radio interference. We maintain a list of the most interesting candidate signals, and we recently reobserved these at Arecibo, but there's nothing that sticks way out of the distribution. AM: What are the plans for the future? DW: Astropulse, the multibeam sky survey at Arecibo [5-10 times more sensitive than previous surveys], more optical SETI [the search for visible or infrared signals from extraterrestrial civilizations], ever larger bandwidths (SERENDIP V and beyond), the Allen Telescope Array, the SKA (square kilometer array), and onward, funding permitting. AM: "Onward" seems to be a kind of motto for the thinking behind SETI@home. DW: Capabilities are doubling every year. I'm optimistic and predict that Earthlings will discover extraterrestrial civilizations in the next 50 or 100 years. Don't hold your breath. What's next? The goal of this vast SETI network is to pick out the one world-changing radio transmission from the billions and billions of possible worlds. No consideration of SETI can be complete without an accounting of how life has prospered, or potentially propagated--the run-down of the chase, strictly by the numbers. The number of stars in the visible universe, for instance, is estimated to be 70 sextillion, or 70,000,000,000,000,000,000,000 [seven followed by twenty-two zeros]. Such a vast population can be compared in a list of the very biggest numbers imaginable, with some terrestrial references borrowed from a combination of science and poetry: ten times more than the number of grains of sand on Earth eleven times the number of cups of water in all the Earth's oceans ten thousand times the number of wheat kernels that have ever been produced on Earth one hundred million times more than the number of ants in all the world one hundred million times the dollar value of all the market-priced assets in the world ten billion times the number of cells in a human being one hundred billion times the number of letters in the 14 million books in the Library of Congress In the realm of astrobiology, it may be said that most meaningful terrestrial analogies to the number of stars in the known universe are indeed biological: only a fertile biosphere can yield such large numbers. One may ask how many living things the Earth itself can accommodate in its volume. If one cubic inch can hold ten billion animal or plant cells, and if one stacked these cells across both the land and oceans to a thickness of fifteen feet, the planet would be a vast teeming mass of biology--literally, life as far as the eye could see. The thickness of fifteen feet, while extreme overpopulation on the land, is likely an underestimate given the depth of the more three- dimensional ocean biosphere or the realms of winged species. In this way, the ceiling on the carrying capacity of Earth for cellular life is vast, since about ten million times the number of plant or animal cells could pack the planet than the number of stars in the visible universe. Compared to 70 sextillion, the cellular capacity terrestrially is estimated to be what can be called one undecillion, or ten raised to the power of 30. Read the original article at http://www.astrobio.net/news/article710.html. ________________________________________________________________________ 10 REASONS TO PUT HUMANS BACK ON THE MOON By Robert Roy Britt From Space.com 8 December 2003 There is no promise that NASA will ever get a directive to send astronauts back to the Moon. Nor is it clear if humans will venture to Mars. But speculation last week that President Bush might be mulling those grand plans had scientists around the world savoring the possibilities. Many researchers believe robotic exploration is the best way to conduct most space science. Others disagree. Only humans can properly investigate other worlds, they say, to answer the most pressing questions about the origin and fate of humans and the possibility that life exists elsewhere. For many space visionaries and practical scientists alike, human spaceflight is about opening up profitable commercial opportunities and, perhaps more important, continuing the immutable human desire to explore. Read the full article at http://www.space.com/news/moon_top10_031208- 1.html. ________________________________________________________________________ NASA LEARNING TO MONITOR CORAL REEF HEALTH FROM THE SKY NASA/ARC release 03-101AR 8 December 2003 Coral reef health may be accurately estimated from sensors on airplanes and satellites in the future, according to a NASA scientist who is the principal investigator in a collaborative project to develop a method to remotely sense coral health. Sometimes called the "bellwether of the seas," coral reefs can give first indications of marine ecosystem health. "Scientists can use coral health as a sensitive indicator of the health of the marine environment," said Liane Guild, a scientist at NASA Ames Research Center, Moffett Field, CA. "We're looking into how you could remotely detect coral reef health using aircraft with visible light sensors," Guild said. "First, we have to look at the coral close up, underwater, to see what spectral reflectance the sensor picks up from diseased, stressed and healthy coral." One of the first steps her team took to develop aerial coral monitoring was to take undersea light-reflectance readings of elkhorn coral with a handheld spectroradiometer. A team of four scuba divers, from the universities of Miami, South Florida and Puerto Rico, helped Guild take the first readings at varying depths in summer 2002 near Andros Island, Bahamas, with assistance from the U.S. Navy Atlantic Undersea Test and Evaluation Center. A spectroradiometer measures the amount of ultraviolet, visible and infrared light reflected from an object, and is similar to sensors aboard remote-sensing airplanes and satellites. "We moved up from the coral, little by little, to the surface to learn how light intensity decreases in the water column, which affects our coral reflected-light readings," Guild said. "There also will be a layer of atmosphere between the coral, the water and the sensor when it eventually flies aboard an airplane to survey the reefs," she added. "The effects of the atmosphere on light are pretty well known, but the challenge is to correct for the effects of the layer of water over the coral," Guild explained. "Instead of taking the top-down approach, we are going from the bottom up to the airplane, and later to satellite sensing of coral health," Guild said. "Ultimately, we plan to fly 'hyperspectral' instruments, containing many detectors that collect information in the visible light range," Guild explained. These instruments will provide the most useful information about coral-reef community health from above the sea, according to Guild. The team's research emphasis is on Acropora palmata, or elkhorn coral, a major reef-building coral. It is prevalent in the study area, but is suffering from "white band disease". Elkhorn coral is on the verge of becoming an endangered species because it has severely declined in many areas of the Caribbean, Guild noted. The team and engineering scientists from the University of Arizona also are developing a specialized computer model to analyze coral reflected-light data. The computer model will help scientists better interpret the raw data gathered by aircraft or satellites. Guild will discuss her group's work at the fall meeting of the American Geophysical Union on December 9, at 5:45 PM PST, in room 3000 of the Moscone Convention Center, San Francisco. The research is funded by NASA's Earth Science Enterprise, which is dedicated to understanding the Earth as an integrated system and applying Earth system science to improve prediction of climate, weather and natural hazards using the unique vantage point of space. For information about NASA's Earth Science Enterprise on the Internet, visit http://www.earth.nasa.gov. For images on the Internet, visit http://amesnews.arc.nasa.gov/releases/2003/03images/coral/coral.html. More information about the coral monitoring project is available at http://geo.arc.nasa.gov/sge/coral-health. Contact: John Bluck NASA Ames Research Center, Moffett Field, CA Phone: 650-604-5026 or 650-604-9000 E-Mail: jbluck@mail.arc.nasa.gov ________________________________________________________________________ NEW ADDITIONS TO THE ASTROBIOLOGY INDEX By David J. Thomas http://www.lyon.edu/projects/marsbugs/astrobiology/astrobiology.html 9 December 2003 Human space exploration articles http://www.lyon.edu/projects/marsbugs/astrobiology/online_articles3.html R. R. Britt, 2003. 10 reasons to put humans back on the Moon. Space.com. K. Miller, 2003. Membranes on Mars. NASA Science News. SETI articles http://www.lyon.edu/projects/marsbugs/astrobiology/online_articles4.html Astrobiology Magazine, 2003. The big crunch: interview with Dan Werthimer. Astrobiology Magazine. P. Backus, 2003. Arecibo diaries IV: the birthday present. Space.com. E. DeVore, 2003. Why don't we just go there? A teachable moment. Space.com. Evolution (biological, chemical and cosmological) articles http://www.lyon.edu/projects/marsbugs/astrobiology/online_articles5.html University of California, Santa Barbara, 2003. Repeated blows: the great dying. Astrobiology Magazine. ________________________________________________________________________ CASSINI SIGNIFICANT EVENTS NASA/JPL release 25 November - 3 December 2003 The most recent spacecraft telemetry was acquired from the Madrid tracking station on Monday, December 1. The Cassini spacecraft is in an excellent state of health and is operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" web page located at http://saturn.jpl.nasa.gov/operations/present-position.cfm. On-board activities this week included uplink of commands in preparation for next week's Probe pre-heating checkout activity, Visual and Infrared Mapping Spectrometer (VIMS), Imaging Science Subsystem (ISS) and Ultraviolet Imaging Spectrograph (UVIS) scattered light observations, VIMS and ISS spectral calibrations, Magnetometer Subsystem and UVIS Hydrogen Deuterium Absorption Cell background calibration rolls, and an array demonstration over the DSN complex in Madrid. On Sunday, Ion and Neutral Mass Spectrometer (INMS) personnel reported an anomalous reboot, which resulted in a burst of alarms seen during the corresponding DSN track. The instrument is in a safe state. Instrument personnel have requested that it be restored to a normal sleep state by December 24 in order to participate in a scheduled telemetry mode test. Until then INMS will remain in a PROM state and be monitored by the team until after upcoming Probe activities have completed. Gravitational Wave Experiment (GWE) #3 ended on the evening of November 30. At that time commands to power off the Ka-band Exciter and Ka-band Traveling Wave Tube Amplifier were executed. The Ka-band Translator has been OFF throughout the experiment. During the last week of the experiment, the instrument continued to collect coherent X-band data and, when available, X-band uplink/Ka-band downlink data. A sequence change request and Preliminary Sequence Integration and Validation approval meeting was held as part of the sequence generation process for C42. The C43 sequence generation process began with stripped sequence files distributed to the participating teams and a kick-off meeting. The Sub-Sequence Generation waiver disposition meeting for this process was cancelled, as there were no waivers to disposition. The first tour aftermarket process began with an assessment meeting for the S01 sequence. All required and proposed additional changes to the sequence were scoped and a recommendation made to accept them pending further analysis. The science operations plan implementation process concluded for the tour S05 and S06 sequences. Products from this activity have been archived and will be activated again in July of 2004 for the start of the S05 aftermarket process. A kickoff meeting was held for the science operations plan implementation process for tour sequences S21 and S22. VIMS personnel completed ground regression testing of instrument flight software version 8.1. The software was delivered to the project software library and the Software Description Document was delivered to the Cassini electronic library. Multi-Mission Image Processing Laboratory software D31 development cycle ended with delivery-to-test made this week. Numerous updates were made to uplink and downlink software. The software set will become operational in February. Cassini Configuration Management received a delivery of the ISS Science Team planning software, ISS Pointing Tool. This software is for use in Support Imaging planning. Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, CA, manages the Cassini mission for NASA's Office of Space Science, Washington, DC. ________________________________________________________________________ MARS GLOBAL SURVEYOR IMAGES NASA/JPL/MSSS release 27 November - 3 December 2003 The following new images taken by the Mars Orbiter Camera (MOC) on the Mars Global Surveyor spacecraft are now available. Windblown Sand Dunes (Released 27 November 2003) http://www.msss.com/mars_images/moc/2003/11/27/index.html Work of Wind on Pavonis Mons (Released 28 November 2003) http://www.msss.com/mars_images/moc/2003/11/28/index.html South Polar Layered Slop (Released 29 November 2003) http://www.msss.com/mars_images/moc/2003/11/29/index.html South Polar Sand Dunes (Released 30 November 2003) http://www.msss.com/mars_images/moc/2003/11/30/index.html Layer Outcrops and Dunes (Released 01 December 2003) http://www.msss.com/mars_images/moc/2003/12/01/index.html Devil-Streaked Crater (Released 02 December 2003) http://www.msss.com/mars_images/moc/2003/12/02/index.html Exhuming Crater in Northeast Arabia (Released 03 December 2003) http://www.msss.com/mars_images/moc/2003/12/03/index.html All of the Mars Global Surveyor images are archived at http://www.msss.com/mars_images/moc/index.html. Mars Global Surveyor was launched in November 1996 and has been in Mars orbit since September 1997. It began its primary mapping mission on March 8, 1999. Mars Global Surveyor is the first mission in a long-term program of Mars exploration known as the Mars Surveyor Program that is managed by JPL for NASA's Office of Space Science, Washington, DC. Malin Space Science Systems (MSSS) and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO. ________________________________________________________________________ MARS ODYSSEY THEMIS IMAGES NASA/JPL/ASU release 1-4 December 2003 Swirling Winds Reflected In Dunes (Released 1 December 2003) http://themis.la.asu.edu/zoom-20031201a.html Disappearing Act (Released 2 December 2003) http://themis.la.asu.edu/zoom-20031202a.html Nili Fossae in Color (Released 3 December 2003) http://themis.la.asu.edu/zoom-20031203a.html Hematite Outlier and Sand Dunes (Released 4 December 2003) http://themis.la.asu.edu/zoom-20031204a.html All of the THEMIS images are archived at http://themis.la.asu.edu/latest.html. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, DC. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena. ________________________________________________________________________ STARDUST STATUS REPORT NASA/JPL release 5 December 2003 The Stardust team has had daily communications with the spacecraft in the past week. Telemetry relayed from the spacecraft indicates it remains in very good shape as it approaches its date with Comet Wild 2 on January 2, 2004. Information on the present position and orbits of the Stardust spacecraft and comet Wild 2 may be found on the "Where Is Stardust Right Now?" web page located at http://stardust.jpl.nasa.gov/mission/scnow.html. Trajectory Correction Maneuver 10 was successfully executed on December 3. The burn duration was 118 seconds. This trajectory correction maneuver places Startdust on a trajectory that is a little inside the 300 kilometer flyby distance planned for Comet Wild 2. Three more trajectory correction maneuvers are planned during the next month to precisely control the flyby to 300 km +/- 50 km. On December 4, the seventh and last of the bi-weekly optical navigation images was taken. Daily optical navigation imaging begins on Monday, December 8th. A JPL news release of "NASA Spacecraft Pinpoints Where the Wild Thing Is" was issued on December 1, which was picked up by other news organizations. An article was published in the Los Angeles Times in the Kid's Corner section on November 26 titled "Giant Snowballs in Outer Space! (They're Actually Comets)". The Stardust mission was highlighted on Los Angeles KKJC 88.1 Jazz Radio on December 2. Space Place created an online Stardust activity called "Tails of Wonder" which is available at http://spacespace.jpl.nasa.gov/stardust. For more information on the Stardust mission--the first ever comet sample-return mission--please visit the Stardust home page at http://stardust.jpl.nasa.gov. ________________________________________________________________________ End Marsbugs, Volume 10, Number 48.