MARSBUGS: The Electronic Astrobiology Newsletter Volume 10, Number 4, 27 January 2003. Editor/Publisher: David J. Thomas, Ph.D., Science Division, Lyon College, Batesville, AR 72503-2317, USA. dthomas@lyon.edu Contributing Editor: Julian A. Hiscox, Ph.D., School of Animal and Microbial Sciences, University of Reading, Reading, RG6 6AJ, United Kingdom. J.A.Hiscox@reading.ac.uk 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 editors, except for specific articles, in which instance copyright exists with the author/authors. While we cannot effectively copyright our mailing list, our readers would appreciate it if others would not send unsolicited e-mail using the Marsbugs mailing list. The editors do not condone "spamming" of our subscribers. Persons who have information that may be of interest to subscribers of Marsbugs should send that information to the editors. E-mail subscriptions are free, and may be obtained by contacting either of the editors. Information concerning the scope of this newsletter, subscription formats and availability of back-issues is available from the Marsbugs web page at http://welcome.to/marsbugs or http://www.lyon.edu/webdata/users/dthomas/marsbugs/. ________________________________________________________________________ CONTENTS 1) COLUMBIA UNIVERSITY RESEARCH FINDS CORRELATION BETWEEN METEORITE AND COMET IMPACTS AND AN INCREASE IN VOLCANIC ACTIVITY DEVELOPMENT Earth Institute at Columbia University release 2) GERMAN CREW TO MAN MARS DESERT RESEARCH STATION By Sven Knuth 3) WORLD'S MOST INTRIGUING LAKE FORMED BY TECTONIC ACTIVITY: NEW DATA SHED LIGHT ON LAKE VOSTOK Earth Institute at Columbia's Lamont-Doherty Earth Observatory release 4) NASA FINISHING UP WORK ON MARS ROVERS From Associated Press and CNN 5) STARGAZERS TO SEE RED From Astrobiology Magazine 6) MARS MAY BE MUCH OLDER--OR YOUNGER--THAN THOUGHT, ACCORDING TO RESEARCH BY UB PLANETARY GEOLOGIST University at Buffalo release 7) GEOLOGY OF EUROPA: EVIDENCE FOR WATER? By Cynthia Phillips 8) SHOCK WAVES THROUGH THE SOLAR NEBULA COULD EXPLAIN WATER-RICH SPACE ROCKS By Lori Stiles 9) METEORITE HINTS AT MARS'S WATERY PAST From Agence France-Presse and SpaceDaily 10) NUCLEAR FUSION COULD POWER NASA SPACECRAFT By Duncan Graham-Rowe 11) MARS SOCIETY STEERING COMMITTEE ISSUES RESOLUTION SUPPORTING SPACE NUCLEAR POWER Mars Society release 12) NUCLEAR POWER IN SPACE AND THE IMPACT ON EARTH'S ECOSYSTEM By Bruce K. Gagnon 13) EARLY MARS: OCEANS AWAY? By David Tenenbaum 14) NEW ADDITIONS TO THE ASTROBIOLOGY INDEX By David J. Thomas 15) CASSINI SIGNIFICANT EVENTS NASA/JPL release 16) INTERNATIONAL SPACE STATION SCIENCE OPERATIONS STATUS REPORT NASA/MSFC release 03-115 17) MARS ODYSSEY THEMIS IMAGES NASA/JPL/ASU release 18) STARDUST STATUS REPORT NASA/JPL release ________________________________________________________________________ COLUMBIA UNIVERSITY RESEARCH FINDS CORRELATION BETWEEN METEORITE AND COMET IMPACTS AND AN INCREASE IN VOLCANIC ACTIVITY DEVELOPMENT Earth Institute at Columbia University release 17 January 2003 Supporting the theory that catastrophic events significantly influence major Earth processes, researchers have determined that comet and meteorite impacts on Earth occurring over the last 4 billion years have directly correlated with the activity of strong and normal mantle plumes--heated mantle rock causing volcanic eruptions (e.g. Hawaii, Iceland). Dr. Dallas Abbott, of the Lamont-Doherty Earth Institute, and Ann Isley, of SUNY Oswego, assembled an expanded database of terrestrial impacts over the last 4 billion years. They used clues from known craters such as impact spherules created from impact melt, and from impact breccias that are created from shattered debris fused under high temperatures and pressures. They also examined the activity of normal and strong mantle plumes over geological time. Time series derived from this data showed that 10 major peaks in terrestrial impact activity were seen on Earth over this time period. Nine out of 10 of these impact peaks are directly matched by peaks in normal to strong mantle plume volcanism. In addition, there are two prominent lulls in impact activity, also corresponding to periods of lower activity of mantle plume volcanism. The biggest mystery remaining is the mechanism by which large impacts might intensify volcanism. Abbott and Isley propose three possibilities: impacts may cause cracking and de-stressing of the crust, allowing melts that had been trapped due to tectonic stress and/or impermeable boundaries to rise more easily to the surface; impacts may produce large cracks in the surface of the Earth allowing new plate boundaries to form with consequent thinner lithosphere and longer melt columns; or impacts may produce microdikes at the core mantle boundary, which, if very thin, would allow molten core and mantle material to mix, increasing the amount of heat available for melting the mantle and producing a rapid intensification of existing mantle plumes. Another question raised by the correlation between impacts and volcanism concerns widely adopted theories that meteorite and comet impacts were the cause of mass extinctions of life on Earth. Was it the impact alone or could major episodes of mantle plume volcanism have contributed to these extinctions? Dallas Abbott is an adjunct research scientist at The Lamont-Doherty Earth Observatory. Her primary research focus is the thermal history of the earth, and the manner in which heat transport through the crust and upper mantle influences geological processes, both ancient and present- day. Abbott and Isley's research paper, "Extraterrestrial Influences on Mantle Plume Activity," is appearing in Earth and Planetary Science Letters this month. The Lamont-Doherty Earth Observatory, a research unit of the Earth Institute, is one of the world's leading research centers examining the planet from its core to its atmosphere, across every continent and every ocean. From global climate change to earthquakes, volcanoes, environmental hazards and beyond, Observatory scientists continue to provide the basic knowledge of Earth systems that must inform the future health and habitability of our planet. The Earth Institute at Columbia University is the world's pioneer academic center for mobilizing the sciences and public policy in pursuit of a sustainable future, especially for the world's poor. Its director is international economist Jeffrey D. Sachs. More than 800 scientists with strength in Earth science, ecology, health, social science or engineering are working together to reduce poverty, hunger, disease and environmental degradation. The Institute brings their creative knowledge to bear through teaching, research and outreach in dozens of countries around the world. In all it does, the Earth Institute remains mindful of the staggering disparities between rich and poor nations and the tremendous impact that global-scale problems--from the AIDS pandemic to climate change to extreme poverty in much of the developing world-- will have on all nations. Contact: Mary Tobin Phone: 845-365-8607 Read the original news release at http://www.earthinstitute.columbia.edu/news/2003/story01-17-03.html. ________________________________________________________________________ GERMAN CREW TO MAN MARS DESERT RESEARCH STATION By Sven Knuth Mars Society release 20 January 2003 The Mars Society announced today that the 13th rotation of the Mars Desert Research Station (MDRS) will consist of an all-German crew. The team, known as "D1" will start its scientific work on board of the MDRS on February 1st. Their mission will last two weeks. While the MDRS program has included participation from individuals from many nations, including Germany, the D1 mission represents the first time an entire crew has been drawn from a single nation other than the United States. It thus represents a new level of international participation in the program. The D1 crew Klaus Totzek: Is an architect, member of the board of the German Mars Society and a member of the American institute of Aeronautics and Astronautics. Just like Dr. Diel he is a hobby astronomer at the "Physikalischen Verein" Frankfurt am Main. He conducts the interior design together with the other members of the team for the European Mars analogous station. In addition he supports the interdisciplinary outline at the technical university of Darmstadt for a Mars habitat. He will conduct the tests with a balloon and will serve as Commander of the MDRS--D1 mission and as engineer on board. Heike Wierzchowski: Is a graphic designer, member of the German Mars Society and will serve as the first officer of the mission. She will continue the study of Bill Clancey of the NASA Ames Research centre which was started during the 5th rotation. It is all about the optimization of workflows and the design of habitats. In addition she will be responsible for the greenhouse together with Horst Gehrmann. Sigrid Belzer: She is a geologist of the Technical University of Darmstadt. She will manage the geological projects of the team. There she is responsibly for up to 3 meters deep drillings and all other geological research onboard the MDRS. Dr. Patrick Diel: He is biologist in Cologne at the German University of Physical Education. In his leisure time he deals with astronomy and he is member of the "Physikalischen Verein" in Frankfurt am Main too. He will carry out DNA tests for the check of a possible contamination of rocks by the astronauts. In addition, he supervises the physical constitution of all crewmembers during EVA. Due to his personal interest he will be responsible for the observatory onboard the MDRS. Horst Gehrmann: H. G. Ewers alias Horst Gehrmann works as a science author and is known also as an author of the science fiction novel Perry Rhodan. Among other things he has a medical and astronomical education and is interested in botany. Therefore he will conduct our medical tests and is responsible for the greenhouse. In addition he will execute measures of UV-radiation. This is part of a preparatory test for a later mission on the MDRS from Dr. Petra Rettberg. She works for the German space agency (DLR), institutes of aerospace medicine, radiation biology section, Cologne. Horst Gehrmann is also member of the German Mars Society. Tom Dirlich: He studies space-flight engineering and architecture at the Technical University Munich. He worked on a habitat for extreme environments (HEXE). In addition, he was involved substantially in the construction of water-beds for the use in the weightlessness. Since the manufacturer and sponsor of this mission TASSO would like to develop beds for a manned Mars mission, Tom Dirlich will make the first fundamental research in this area. The mission is support by several companies and institutes and will focus on biological and astrobiological issues. Besides measurements of the UV radiation for future research the contamination of the surroundings landscape with DNA from the "astronauts" will be researched. We will also see a continuation of the sample extraction demonstration for MASSE (Microarray Assey for Solar System Exploration) which was started by Dr. Markus Landgraf at the FMARS station. A report of his first demonstration can be found here: http://www.mpi- hd.mpg.de/galileo/~landgraf/research/fmars02/report.pdf. Other research issues include some the health status of team members during EVAs, sleeping during low-gravity, architectural issues of Mars habitats and cartography with a balloon. The MDRS In order to help develop key knowledge needed to prepare for human Mars exploration, and to inspire the public by making sensuous the vision of human exploration of Mars, the Mars Society has initiated the Mars Analog Research Station (MARS) project. A global program of Mars exploration operations research, the MARS project will include four Mars base-like habitats located in deserts in the Canadian Arctic, the American southwest, the Australian outback, and Iceland. In these Mars- like environments, we will launch a program of extensive long-duration geology and biology field exploration operations conducted in the same style and under many of the same constraints as they would on the Red Planet. By doing so, we will start the process of learning how to explore on Mars. You can find further information and pictures of the MDRS-D1 mission at http://www.marssociety.de/html/modules.php?op=modload&name=insert&file=index&req=listarticles&secid=90&menuID=M34000 Contact: Sven Knuth Mars Society Deutschland e. V. http://www.marssociety.de For further information about the Mars Society, visit our web site at www.marssociety.org. ________________________________________________________________________ WORLD'S MOST INTRIGUING LAKE FORMED BY TECTONIC ACTIVITY: NEW DATA SHED LIGHT ON LAKE VOSTOK Earth Institute at Columbia's Lamont-Doherty Earth Observatory release 21 January 2003 The cavity which became Lake Vostok, a body of water located beneath more than 4 km of ice in the middle of East Antarctica, was formed by tectonic processes in the earth's crust millions of years ago, Columbia University's Michael Studinger and colleagues reveal in an article published on January 21st in the journal, Earth and Planetary Science Letters. Studinger, a geophysicist at the Earth Institute at Columbia's Lamont- Doherty Earth Observatory, and colleagues studied Lake Vostok and its surroundings, and discovered that the earth's crust changes dramatically from one side of the lake to the other, as shown by data on gravity, magnetism and topography. The research, funded by the National Science Foundation's Office of Polar Programs, suggests that Vostok lies along a faultline, in a cavity formed when two areas of crust crumpled together. An earthquake and aftershock captured by the team's instruments also supported the conclusion that the subglacial lake's thermal energy comes from tectonic processes. This was the first earthquake ever detected in East Antarctica, a region not previously thought to be seismically active. Lake Vostok and the mountains around it are completely invisible from the surface of the Antarctic continent. Says Studinger, "It's fascinating to stand on a flat, glaring white expanse of ice, and know that deep below you, 4 km below, is a fragile world of strange beauty." The lake is kept liquid because of the enormous pressure of its ice cover. About 80 other subglacial lakes have been discovered, but Vostok is by far the largest. The "boundary conditions" of Vostok-including its ice and rock structure and the mountains and valleys that influence the flow of ice and water- have worked together to support the development of a unique ecosystem that "may contain microorganisms with distinct adaptations to such an extreme environment," the authors write. These microbes are supported by nutrients and small amounts of thermal energy introduced through faultlines, while other nutrients come into the lake in sediment that is scraped from the surrounding rock by rivers of flowing ice (the lake's ice flow was documented in an earlier paper in Nature). Data collection was an exercise in extreme conditions as well. The team spent three weeks living in tents in temperatures that never rose above -28 degrees Celsius (-22 degrees Fahrenheit). At 11,440 feet above sea level, Vostok's air is thin and leaves researchers short of breath as they carry out their tasks. Studinger, who stayed on in unheated tents with only four colleagues for an additional week of data collection, describes long days spent engaged in unglamorous activities such as lugging car batteries by snowmobile to instrument stations. "You have to like the cold," he says. The current paper provides the first comprehensive maps of Lake Vostok's ice thickness, geological framework, and the terrain under and around the lake as well as an understanding of how these factors influence water flow and other pieces of the Vostok ecosystem. In the future, the Columbia team hopes to design an observatory that can be inserted into the lake so that Vostok can be studied without introducing any microorganisms from the outside world. The Earth Institute at Columbia University mobilizes the sciences and public policy in pursuit of a sustainable future. Directed by international economist Jeffrey D. Sachs, the Earth Institute's more than 800 scientists are engaged in teaching, research and outreach in dozens of countries, working across disciplines to reduce poverty, hunger, disease and environmental degradation. The Lamont-Doherty Earth Observatory is the only research center in the world examining the planet from its core to its outermost atmosphere, across every continent and every ocean. From global climate change to earthquakes, volcanoes, shrinking resources, environmental hazards, and beyond, LDEO scientists continue to provide the basic knowledge of earth systems that must inform the difficult choices necessary for wise stewardship of our planet. For more information, visit www.earth.columbia.edu. Contact: Mary Tobin Phone: 845-365-8607 Read the original press release at http://www.earthinstitute.columbia.edu/news/2003/story01-21-03.html. ________________________________________________________________________ NASA FINISHING UP WORK ON MARS ROVERS From Associated Press and CNN 21 January 2003 NASA is readying identical twin rovers for a mission to Mars, where the six-wheeled buggies will prospect for geologic evidence that the red planet once had enough water to support life. Engineers at the U.S. space agency's Jet Propulsion Laboratory are scrambling to finish assembling and testing the two rovers for launch on separate rockets in May and June. The $800 million double mission marks NASA's second and most ambitious bid yet to roam the surface of Mars. Read the full article at http://www.cnn.com/2003/TECH/space/01/21/mars.rovers.ap/index.html. ________________________________________________________________________ STARGAZERS TO SEE RED From Astrobiology Magazine 22 January 2003 2003 offers a unique terrestrial vantage point for observing some of our nearest skyward neighbors, particularly to those looking for brighter reddish spots in the night sky. Mars, the Red Planet, will be making its closest approach to Earth in at least 50,000 years this summer. Even without a big telescope, Mars will stand out for stargazers with reddish light--as bright as giant Jupiter--and reveal elusive surface details to amateur and professional astronomers alike. The new year also promises two total eclipses of the moon--the first visible in parts of the United States in more than three years--and an assortment of meteor showers and beautiful conjunctions of moon and planets. But, barring an unexpected bright comet or meteor approach, Mars may get the most attention from stargazers. During the summer months this year, the "spirograph-like", elliptical Earth and martian orbits will bring Mars to within 35 million miles of Earth. The next nearest approach won't occur again until the 23rd century. Mars can vary in its proximity to Earth by nearly ten percent. Even small telescope viewers will be able to follow and photograph seasonal changes in the polar caps, surface features and hints of martian weather in the clouds that form around Olympus Mons, the largest volcano in the solar system. On Mars, super-sized volcanoes sculpted the landscape by releasing huge amounts of lava. The much heralded martian surface features, including the darker colorations and dry channel networks that led Percival Lowell to declare them as "canals", will be big and bright all summer long this year. The year's first lunar eclipse will begin just after 10:00 PM EDT on May 15. Total eclipses of the moon occur when the moon passes through the circular shadow that the Earth casts into space and is fully shaded from direct sunlight. Although masked by the Earth completely or partially from the Sun for as much as an hour and a half, scattering of sunlight off the limbs of our atmosphere doesn't leave the moon without illumination. Instead the blood-bright color of long-wavelength red light enshrouds the moon's otherwise familiar grey pallor. If skies are clear, observers will watch the sunlit moon slowly engulfed and dimmed by the shadow's darkness. Totality will last 53 minutes, from 11:14 PM until 12:06 AM EDT, with the moon's face turned an eerie, coppery color. The hue is produced by sunlight filtered, reddened and scattered by the rim of the Earth's atmosphere. Because of changes in terrestrial dust in the atmosphere, each lunar eclipse is unique in appearance. The Moon is believed to play an important role in Earth's habitability. Because the Moon helps stabilize the tilt of the Earth's rotation, it prevents the Earth from wobbling between climatic extremes. Without the Moon, seasonal shifts would likely outpace even the most adaptable forms of life. The second eclipse will occur on Saturday evening, November 8. What next? NASA does have funding in its budget to investigate some questions relevant to possible future human exploration of Mars. The 2001 Mars Odyssey, for example, an orbiter launched on April 7, 2001, contains an experiment to measure the amount of damaging radiation that humans traveling to Mars would need to protect themselves against. Two Mars Exploration Rovers (MERs) will be launched by NASA in 2003. Experiments performed by the MERs will help to determine whether resources are available on Mars that will be needed to support humans living there. The two Mars Exploration Rovers are targeting what imagery indicates might have been ancient dry lake beds and other geologically interesting sites in early 2004. One enhanced feature of the MER mission plan is more mobility for its rovers. Compared to the stunningly successful Pathfinder mission in 1997, these bigger Mars Exploration Rovers (MER) can trek up to a football field--330 feet (100 meters)--per martian day. Making remote maneuvers over those distances means getting very good topological maps, while knowing where every interesting rock or hazard might tip and block the rovers' paths. Seen globally, the darker areas on Mars are generally rockier while the bright areas are dusty, but a much enhanced topography goes into site selection beforehand, and then much later after landing to roam the surface. Potentially hundreds or thousands of pebbles and boulders can pock mark a landing site on the scale of a 100 yards per day. In total, the football field milestone is almost as far in one martian day as the 1997 Sojourner rover did over its entire, many-month-long lifetime. Starting in January 2004, MER surface operations will last for at least 90 martian days, or longer if hardware health is maintainable. Once an interesting target is identified on the ground, the Mars Rovers' will employ what is their primary science payload, a collection of 5 instruments (and a rock abrasion tool) called the Athena package. Mission planners look forward to even more close-up views of the two primary sites slated for the early 2004 rendezvous. The European Space Agency will also launch a mission in 2003, a combined orbiter/lander. Current plans are for its lander, Beagle 2, to contain biological experiments designed to search directly for evidence of life on Mars. Future missions to Mars will perform additional experiments to understand better the possibilities and challenges of supporting a human mission. And astronauts living aboard the International Space Station will improve NASA's understanding of the effects of long-term exposure to microgravity. But NASA's Mars-exploration roadmap for the next 20 years contains no plan to actually send human explorers there. Read the original version of this article at http://www.astrobio.net/news/article360.html. ________________________________________________________________________ MARS MAY BE MUCH OLDER--OR YOUNGER--THAN THOUGHT, ACCORDING TO RESEARCH BY UB PLANETARY GEOLOGIST University at Buffalo release 23 January 2003 Research by a University at Buffalo planetary geologist suggests that generally accepted estimates about the geologic age of surfaces on Mars- -which influence theories about its history and whether or not it once sustained life--could be way off. Funded by the National Aeronautics and Space Administration, the research eventually could overturn principles about the relative ages of different areas on the Red Planet that have not been questioned for nearly 20 years. The findings also could cause scientists to reconsider the use of a critical tool-- counting impact craters created by meteorites--that geologists use to estimate the age of planets they cannot visit in person. "This has the potential to change everything we thought we knew about the age of different surfaces on Mars," said Tracy Gregg, Ph.D., assistant professor of geology at UB and chair of the Planetary Geology Division of the Geological Society of America. David Crown, Ph.D., of the Planetary Science Institute, is Gregg's co-investigator on the grant. Gregg's research concerns an area on Mars called Hesperia Planum, which has been used since the 1980s to define the Hesperian epoch, the second of the planet's three geologic time periods. But in the past several years, recent analyses of images obtained from the Mars Orbiter Laser Altimeter, (MOLA), the Mars Orbiter Camera (MOC) and other instruments have led to new estimates for the duration of the Hesperian epoch, ranging from just 300,000 years to 1-2 billion years, Gregg explained. While other planetary geologists now are attempting to reconcile these two models, she said, her focus is on trying to figure out which surfaces on Mars originated in the Hesperian epoch, research that, in turn, probably will help to further define the duration of the Hesperian epoch. "For almost 20 years, Hesperia Planum has served as the basic time marker on Mars," said Gregg. "When we want to identify how old rocks are without the benefit of samples, we count impact craters, the big holes in planetary surfaces that are made by meteorites that crash into them," explained Gregg. "The more impact craters there are on a surface, the older it is." But during the course of Gregg's research reviewing images of Tyrrhena Patera, a volcano located in the middle of Hesperia Planum, she began finding deposits from not one martian geologic epoch but from several. Gregg made her findings using images obtained from the Viking Orbiter, the Mars Global Surveyor, the MOLA and the MOC. She also will be using data NASA is making available from THEMIS, the Thermal Mapping Infrared Spectrometer, which measures surface temperatures on Mars. "Hesperia Planum is not one age. Its surface actually is a combination of materials that are very old, materials that are very young and some that are in between," she said, "and the volcanoes there are the reason why." Gregg recently has demonstrated that two volcanoes in western Hesperia Planum were active during a much longer period than previously was understood and that the products of the eruptions traveled much further, signaling a greater intensity of volcanic activity than originally was thought. Her findings, she said, are similar to ones made about 20 years ago on Earth, when geologists discovered that Yellowstone National Park in Wyoming was the center crater of an enormous volcano and that its deposits stretched as far as the state of Illinois. Those findings, she said, changed fundamentally the understanding of volcanic activity on Earth. In a similar vein, she said, the new observations about the great distances traveled by deposits of martian volcanoes and their influence on the age of surfaces may cause a similar reconsideration of understanding of the history of Mars. "I think that we are about to discover that Hesperia Planum, this surface that has acted as a basic time marker for Mars, has a very different age than we thought," she said. "If it turns out it's much older than we thought, then it means that the system shut down a lot earlier and the chances of finding active living organisms on Mars are much slimmer. "If, on the other hand, it turns out to be much younger, then it means Mars still may be volcanologically active, and if it is, that increases the possibility of extant life on Mars." Contact: Ellen Goldbaum Phone: 716-645-5000 ext 1415 Fax: 716-645-3765 E-mail: goldbaum@buffalo.edu Read the original press release at http://www.buffalo.edu/news/fast- execute.cgi/article-page.html?article=60460009. An additional article on this subject is available at http://www.spacedaily.com/news/mars-general-03a.html. ________________________________________________________________________ GEOLOGY OF EUROPA: EVIDENCE FOR WATER? By Cynthia Phillips From Space.com 23 January 2003 In two previous articles, we considered the Galilean satellites and the fact that tidal flexing, due to their resonant orbits, provides heat for volcanism on Io and could result in the presence of liquid water beneath Europa's icy surface. The Galileo spacecraft, which is currently finishing its mission in the Jovian system, took a number of images of Europa's surface between 1995 and 2001 that can be used to study the geology of this small moon and look for evidence of liquid water beneath the surface. ...The geology of Europa provides some tantalizing clues that liquid water may have been, or currently be, present beneath Europa's icy surface. However, images of the surface can not prove the existence of liquid water. Fortunately, some other types of geophysical evidence do provide more definitive detections of water, and these will be examined in a future article. Read the full article at http://www.space.com/searchforlife/seti_phillips_europa_030123.html. ________________________________________________________________________ SHOCK WAVES THROUGH THE SOLAR NEBULA COULD EXPLAIN WATER-RICH SPACE ROCKS By Lori Stiles University of Arizona release 23 January 2003 Shock waves through icy parts of the solar nebula could well be the mechanism that enriched meteorites with water--water that some believe provided an otherwise dry Earth with oceans, according to a new study published in today's issue (January 24) of Science [http://www.sciencemag.org/cgi/content/abstract/299/5606/549]. Scientists have long debated how "chondrules" might have formed. Chondrules are millimeter-sized blobs of once-melted minerals found within chondritic meteorites, which are thought to be the oldest objects in the solar system. In some of these meteorites, chondrules are rimmed by fine silicate dust particles that have reacted with water. Researchers at first speculated that chondrules and their water-rich rims formed when water molecules in the solar nebula collided with dust. But a 1987 study dispelled that idea, because the time it would take for the minerals to form in this manner would be longer than the lifetime of the solar nebula. Planetary scientists at the University of Arizona and University of Hawaii now report that chondrule-forming shock waves in icy regions of the nebula could have produced conditions that allowed rapid mineral hydration. Fred J. Ciesla, Dante S. Lauretta and Lon L. Hood of the UA and Barbara Cohen of the University of Hawaii collaborated in the study. Lauretta and Cohen speculated years ago that a big energetic event, like a shock wave, might produce enough energy to vaporize ice particles and briefly create conditions that made such quick hydration reactions possible. Ciesla modeled the scenario of what happened to particles of silicate and ice during a shock wave event. "And what happens is, the ice particles vaporize in this very energetic event, producing high water vapor pressure. During this brief period of increased water pressure, the hydration reaction occurs much faster than previously predicted," Ciesla said. "During this brief period, the chondrules melt and the rims form in the same event." Gas slows as it passes through a shock front, increasing in temperature and density. But solid particles entrained in the gas continue through the shock wave at high velocity. "The solid particles heat up because they are speeding through the slower-moving gas. And just as a meteor is heated up and burns when it enters Earth's atmosphere, particles are heated when they collide with the gas molecules. Gas both heats and slows the chondrules, so they melt and begin to cool. The water vapor then reacts with the dust to form these hydrated silicates, and the chondrules accrete these silicates to form their rims." "An interesting characteristic of these particular meteorites is that they contain a lot of water, and the deuterium-to-hydrogen ratios in that water matches the ratios we find in Earth's water," Ciesla noted. Why Earth has water is a mystery, for "especially early on in the solar nebula, the area where the Earth formed was too hot for water to incorporate into a solid body," Ciesla said. Meteorites may have delivered at least part of Earth's water, although that remains open to debate, he added. The scenario also suggests how so much organic material has survived in the carbonaceous chondrite meteorites. If water reacted with the fine dust in the solar nebula as the new research suggests, temperatures in the meteorites would have remained low enough for organic molecules to survive and be delivered, along with water, to Earth. Although the idea that shock waves formed the hydrated rock and chondrules found in the most primitive meteorites stands up to quantitative analysis, scientists are still speculating about where the shock waves come from, and it's a topic Ciesla hopes to address in his doctoral thesis. UA planetary scientist Lon Hood, one of the authors on the Science paper, originally theorized that as Jupiter was forming, it excited the orbits of the many "planetismals," or planet building-blocks, in the region that became the present day asteroid belt so that they were propelled through the gas in the solar nebula at speeds greater than the speed of sound, creating shock waves. Ciesla has begun testing that idea. Other ideas on the origin of shock waves also involve Jupiter in some way, he said. A high-resolution electron image of chondrule surrounded by a rim of fine-grained dust that has reacted with water can be downloaded at http://www.lpl.Arizona.edu/~fciesla/figs/fig1.tif. The image, courtesy of Dante Lauretta, appears in the Science article. Read the original press release at http://uanews.opi.arizona.edu/cgi- bin/WebObjects/UANews.woa/3/wa/SRStoryDetails?ArticleID=6688. Additional articles on this subject are available at: http://spaceflightnow.com/news/n0301/24meteorites/ http://www.spacedaily.com/news/extrasolar-03d.html ________________________________________________________________________ METEORITE HINTS AT MARS'S WATERY PAST From Agence France-Presse and SpaceDaily 23 January 2003 Analysis of a martian meteorite that fell to Earth suggests that magma rocks beneath the surface of the "Red Planet" were rich in water, a scientific panel that carried out the study said here (Lons-Le-Saunier) on Thursday. The meteorite, NWA 1669, which fell in the Western Sahara, is a basalt rock of a type called shergottite, the commonest signature among the 28 martian rocks recovered on Earth. The Theodore Monod Consortium said the sample was remarkable--and indicated the presence of water on Mars--because of the crystallization pattern that developed in two minerals called pyroxenes after the liquid magma cooled and became rock. One of the pyroxenes, augite, had crystallised before the other, pigeonite. Read the full article at http://www.spacedaily.com/2003/030123181812.5qkebuw8.html. ________________________________________________________________________ NUCLEAR FUSION COULD POWER NASA SPACECRAFT By Duncan Graham-Rowe Fom New Scientist 23 January 2003 The journey time from Earth orbit to Mars could be slashed from six months to less than six weeks if NASA's idea for a nuclear fusion- powered engine takes off. The space-flight engine is being developed by a team led by Bill Emrich, an engineer at NASA's Marshall Space Flight Center in Huntsville, Alabama. He predicts his fusion drive would be able to generate 300 times the thrust of any chemical rocket engine and use only a fraction of its fuel mass. That means interplanetary missions would no longer need to wait for a "shortest journey" launch window. "You can launch when you want," Emrich says. The principle is to sustain an on-board fusion reaction and fire some of the energy created out the back of the spacecraft, generating thrust. Of course, harnessing fusion is no easy task. Scientists have struggled to contain the super-hot plasmas of charged ions needed for fusion reactions. Read the full article at http://www.newscientist.com/news/news.jsp?id=ns99993294. ________________________________________________________________________ MARS SOCIETY STEERING COMMITTEE ISSUES RESOLUTION SUPPORTING SPACE NUCLEAR POWER Mars Society release 27 January 2003 The Steering Committee of the Mars society today issued a resolution supporting the revival of NASA's space nuclear power program. The resolution was approved by a vote of 20 in favor, 1 opposed, 1 abstention, and 7 not voting. The text of the resolution is given below. Mars Society Resolution on Space Nuclear Power The decision by NASA to revive its space nuclear development program is a very positive step that will greatly enhance the prospects for human exploration and settlement of the solar system. The Mars Society applauds any effort to proceed with technology development that supports human exploration of Mars. Using nuclear thermal rockets allows the payload delivered from LEO to the Moon or Mars to be substantially increased, thereby cutting the launch costs associated with lunar or Mars exploration programs. Nuclear power reactors are needed for long duration operation of a Mars base, where they could provide the power for reliable life support, ultra-high data rate communications, and the in-situ production of ascent and return propellants, thereby increasing mission science return and cutting launch costs even more. Beyond Mars, unmanned probes using nuclear power for high specific impulse electric propulsion, active sensing, and high data rate communication could increase mission science return enormously compared to that possible with today's technology. While public concern about the risks involved in launching nuclear power sources is appropriate, we believe that nuclear power can be launched and operated in space without posing a safety or environmental risk to Earth. Launch of a fission reactor which has not yet been started presents no radiation hazard to Earth because, prior to reactor start, no radionuclides have been produced and so radioactivity is negligible Administrator O'Keefe's decision to develop space nuclear power is a wise move that will greatly expand our space capabilities and prove cost-effective. The name "Project Prometheus" is well taken. [According to Greek mythology,] Prometheus gave fire to man, giving us the power needed to create civilization on Earth. NASA's Project Prometheus will give us the power we need to extend human civilization to the heavens. The Mars Society endorses this program and promises to support it energetically in every way we can. We urge all others interested in furthering humanity's prospects in space to do likewise. To find out more about the Mars Society, visit our web site at www.marssociety.org, or contact info@marssociety.org. ________________________________________________________________________ NUCLEAR POWER IN SPACE AND THE IMPACT ON EARTH'S ECOSYSTEM By Bruce K. Gagnon From SpaceDaily 27 January 2003 After a 30-year shutdown of plans for the nuclear rocket, the Bush administration has resuscitated the technology by giving NASA nearly $1 billion in the next five years to expand its space nuclear and propulsion research and development program. "We are still doing exploration of our solar system in covered wagons," says Ed Weiler, NASA's Space Science Chief. "The Nuclear Systems Initiative will open up the railroad." ...During the 1950s and 1960s NASA spent over $10 billion to build the nuclear rocket program which was cancelled in the end because of the fear that a launch accident would contaminate major portions of Florida and beyond. NASA's expanded focus on nuclear power in space "is not only dangerous but politically unwise," says Dr. Michio Kaku, professor of nuclear physics at the City University of New York. "The only thing that can kill the U.S. space program is a nuclear disaster. The American people will not tolerate a Chernobyl in the sky." Read the full article at http://www.spacedaily.com/news/nuclearspace- 03b.html. ________________________________________________________________________ EARLY MARS: OCEANS AWAY? By David Tenenbaum 27 January 2003 During the 1970s, photos from the first Mars orbiters showed dry river channels that were apparently quite ancient--dating from the first 500 million years of the planet's existence. The river valleys implied liquid water, raising the possibility that life might have developed. Today, the martian surface is cold and dry, and astronomers and climate modelers have struggled to explain such warm conditions in the early years, when the sun was considerably weaker. The leading theory is that early Mars had a thicker atmosphere, which generated a potent greenhouse effect. But to some researchers, this idea seems insufficient to account for above-freezing temperatures. Owen Toon, of the laboratory for atmospheric and space physics at the University of Colorado, says greenhouse gases cannot explain the presence of liquid water on early Mars. "There was no way for Mars to ever have had this warm, moist greenhouse climate," he says. An alternative explanation for the early erosion that made river valleys is colossal energy releases from asteroid impacts. About 25 craters more than 100 kilometers in diameter are visible on Mars, says Toon, reflecting a period of titanic asteroid collisions in the early solar system. A new model of these impacts on Mars, described by Toon, Teresa Segura, and coauthors in Science (December 6, 2002) [http://www.sciencemag.org/cgi/content/abstract/298/5600/1977], paints a picture of a planet where conditions see-sawed between frigid and torrid. Instead of the slow and steady warmth of an enhanced greenhouse effect, this model shows a planet much less hospitable to life. Toon says that, between impacts, early Mars was "a big frozen iceball." But after the impact of an asteroid 50 to 250 kilometers (30 to 155 miles) across, the atmosphere would have filled with vaporized rock hotter than 1,000 degrees C (1832 degrees F). "Within weeks or months, depending on the asteroid's size, the rock vapor condenses and forms a layer of rock on the surface," Toon says. Because both the asteroid and the impact zone probably contained ice, the atmosphere also fills with hot steam, causing several years of rainfall. According to the calculations of Toon's group, this water caused erosion and left evidence of rivers, lakes and small oceans on Mars. But the hot, wet conditions were ephemeral: the planet froze within a few decades or centuries. Only after the collision of another asteroid, perhaps 10 to 20 million years later, did the warmth return. Although the detailed calculations of martian conditions are new, the possibility of a link between impacts and erosion features is not. Via email, Vic Baker, head of the Department of Hydrology and Water Resources at the University of Arizona, said several researchers during the 1980s noted that large, early asteroid impacts "would induce hydrothermal phenomena and could produce small valley networks." But the asteroids don't deserve all the credit, Baker added, especially for the younger valleys. "That is why Gullick and I, and others, have favored volcanic-induced climatic changes for some valley formation." All in the timing Mike Carr, a Mars specialist at the U.S. Geological Survey, says the impact theory suffers from a "timing problem." The ancient craters that Toon and company used as putative sources of energy look much older than many of the valleys they supposedly created. "There are simply no large impacts that are as fresh and well preserved as the valleys," he says. In other words, if the accumulation of erosion is an indicator of age, the craters, many of them almost entirely filled in, must be much older than the valleys. Carr would not entirely discount impacts as a source of heat, however. "It does not invalidate the basic premise of impact craters as possibly causing the conditions, it just has to be a rain of much smaller bodies, not the very rare, large impacts" that Toon and the others studied. "They are simply not contemporaneous with the valleys." Another argument against the impact theory concerns erosion on the rims of some ancient craters, which seems to indicate that the craters are older than whatever caused the erosion. Not necessarily so, Toon says. "Even if that impact happened to form the crater in question, the impact comes first, and the crater comes second. You get 10 to 100 years of flowing water after the formation, so the erosion could have occurred immediately after impact." In terms of astrobiology, the impacts produce "a very different scenario for the origin of life," says Toon. "You just don't have long, warm period of abundant liquid water. You still have liquid water underground, so you could still have life deep in the interior, but things are not pleasant on the surface." If the impact scenario is correct, the river valley networks are not a good place to look for evidence of life, Toon says. "It's just not the right place; they are probably ephemeral." A better place, he says, are the much younger gullies, which were apparently fed by hydrothermal water. "They tapped into underground aquifers for a long life, maybe millions of years," Toon says. The best way to solve the dispute, Toon says, would be to land on the planet. "The most fruitful way to prove impacts would be to examine thick layers of material that the valleys cut through." If they are remains of standing water produced under the greenhouse scenario, he says, "They should show a normal rate of dust infall. It would take millions of years, the sediment might look heavily processed by water, and the particle sizes would be small." If the layers were composed of hot rock that fell after asteroid impacts, however, they would have "been laid down pretty quickly and melted out groundwater, so you might expect an association with some sort of groundwater release." The particles themselves would also be different, he adds. "You would see shocked quartz and pieces of meteorite." The distinction, he says, could be made pretty quickly, upon close examination, but it may take a space-suited geologist with a rock hammer. "I don't think an orbiter will tell us. You have to sample the layers." Read the original article at http://www.astrobio.net/news/article365.html. ________________________________________________________________________ NEW ADDITIONS TO THE ASTROBIOLOGY INDEX By David J. Thomas http://www.lyon.edu/webdata/users/dthomas/astrobiology/astrobiology.html 27 January 2003 Astrobiology, exobiology and terraformation articles http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_articles1. html Agence France-Presse, 2003. Meteorite hints at Mars's watery past. SpaceDaily. Associated Press, 2003. NASA finishing up work on Mars rovers. CNN. C. Phillips, 2003. Geology of Europa: evidence for water? Space.com. D. Tenenbaum, 2003. Early Mars: oceans away? Astrobiology Magazine. University at Buffalo, 2003. Mars may be much older or younger than thought. SpaceDaily. Human space exploration and microgravity effects articles http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_articles3. html Astrobiology Magazine, 2003. Stargazers to see red. Astrobiology Magazine. J. Banke, 2003. Shuttle Columbia crew doing well, studies calcium loss. Space.com. Evolutionary biology and chemistry articles http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_articles5. html Agence France-Presse, 2003. L. Stiles, 2003. Shock waves may explain water in meteorites. Spaceflight Now. L. Stiles, 2003. Shock waves through solar nebula may explain water- rich space rocks. SpaceDaily. ________________________________________________________________________ CASSINI SIGNIFICANT EVENTS NASA/JPL release 16-22 January 2003 The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Wednesday, January 22. 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 clearing of the ACS high water marks, a Reaction Wheel Assembly mode transition to support Cassini Plasma Spectrometer (CAPS), Visual and Infrared Mapping Spectrometer (VIMS) and RADAR activities, Radio and Plasma Wave (RPWS) High Frequency Receiver calibrations, uplink and execution of the VIMS flight software V6.1 checkout mini-sequence, CAPS Calibration activities, VIMS / Imaging Science Subsystem (ISS) observations of Gamma Crux and Alpha Taurus, RADAR radiometric calibrations, a Radio Science Subsystem (RSS) Ultra Stable Oscillator characterization, RSS Periodic Instrument Maintenance and high gain antenna boresight calibration, Ultraviolet Imaging Spectrograph bright body observations of Orion's beta, gamma, zeta and kappa, and a VIMS observation of Fomalhaut. The observations of Alpha Taurus, Gamma Crux, Fomaulhaut, and Orion's Beta, Gamma, Zeta, and Kappa consist of 18 ISS Narrow Angle Camera images, 48 Wide Angle Camera images, and 96 image cubes collected using the version 5.1 VIMS flight software. All data was processed by the Multimission Image Processing Laboratory. During the DOY 019 DSS-45 track, sixteen Magnetospheric Imaging Instrument (MIMI) channels went into alarm. It was determined that the MIMI CPU had halted because of a stack overflow. A real-time command was uplinked to reload the flight software and perform a memory readout of the crashed RAM. The Low Energy Magnetospheric Measurement Subsystem replacement heater was also powered on as a precaution. MIMI has elected to remain in this thermally safe state until it is powered off before the start of C36. Cosmic Dust Analyzer personnel have detected dust in the region between Jupiter and Saturn. Although the rate is very low (about 1/month), this measurement is the first highly reliable dust impact detection at such distances from Sun. The clear impact signals are very similar to ground based measurements and therefore are believed to be 100% reliable. The last impact occurred on January 09, 2003 at 8.0 Astronomical Units. The relative impact speeds of the particles are 50 km/s or higher and their sizes are below 0.1 microns. A wrap up meeting was held this week for completion of the Science Operations Plan (SOP) implementation activity for tour sequences S13 and S14. The products have been archived and will be revisited in April of 2005 when they begin the SOP Update process. A kick-off meeting was held this week for Science Operations Plan development for tour sequences S17 and S18. Science Planning presented a revision to the tour Science Operations Plan Update process at the Cassini Design Team meeting. The Attitude Control (ACS) Flight Software Team held a successful Software Requirements and Certification Review for version A8 of the ACS flight software. This final delivery is a major milestone in ACS Flight Software Development. A8 will provide all the capabilities required for orbital tour operations as well as the Saturn Orbit Insertion and Probe Relay. The Flight Team will uplink and checkout the software on the spacecraft beginning in February. The Command and Data Subsystem Team completed the first phase of the end-to-end system mode test of their procedures for the uplink and checkout of the Version 9 software. A support equipment problem precluded the telemetry mode test over the three-day weekend. Up to that point, all testing was completed successfully. Testing will resume on February 3. Over the last several months Instrument Operations (IO) personnel have been involved in the installation of new Remote Terminal Interface Units (RTIU). These units have an important new feature. They can replay a test exactly as run in the Integrated Test Laboratory (ITL) directly from the RTIU to the instrument Engineering Model without involving ITL. This can be done for any instrument, regardless of whether that instrument's engineering model was connected to ITL at the time the test was run. It also removes an enormous load from the always-full ITL schedule. IO is currently making use of this feature to help diagnose a recent ITL test of VIMS that did not perform as expected. This RTIU feature will let VIMS rerun the ITL test whenever and however many times they wish without scheduling any more time in ITL. 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. ________________________________________________________________________ INTERNATIONAL SPACE STATION SCIENCE OPERATIONS STATUS REPORT NASA/MSFC release 03-115 24 January 2003 Expedition Six Zeolite Crystal Growth research was successfully completed this week aboard the International Space Station. Commander Ken Bowersox removed the 19 sample tubes from the crystal growth furnace on Monday following a 15-day processing run. The samples were stowed for return on the ULF-1 Space Shuttle mission to the Station. The goal of this experiment is to grow larger, more perfect zeolites for study on Earth. Zeolites are used in many manufacturing processes, including petroleum refining. Improving zeolites could make gasoline production more efficient or lead to ways of storing and using clean-burning hydrogen for fuel. Also on Monday, the Payload Operations Center and the Station crew successfully upgraded software for EXPRESS Rack 1 in the Destiny lab. This upgrade is expected to make science operations smoother. Two racks have received the new software, with three more scheduled. EXPRESS Racks provide Station experiments with utilities such as power, cooling, fluids, communications and more. The crew also inspected the sample containers for the Investigating the Structure of Paramagnetic Aggregates from Colloidal Emulsions (InSPACE) experiment in preparation for processing once the Microgravity Science Glovebox is repaired. One of six sample containers was discovered to be cracked. However, an identical backup sample container was intact, so the science team expects to complete all its objectives for the experiment with minimal impact. InSPACE is designed to obtain basic data on magnetorheological fluids - a new class of "smart materials" that can be used to improve or develop new brake systems, seat suspensions, robotics, clutches, airplane landing gear, and vibration damper systems. The Glovebox, which provides a sealed work volume for crews to work safely with experiments involving fumes, fluids or flames, lost power on November 20, 2002. Repair parts will be launched next month aboard a Russian Progress resupply ship, which should restore the Glovebox to working order. Also on Tuesday, the crew completed the 90-day checkout with the Gas Analyzer System for Metabolic Analysis Physiology (GASMAP), used for periodic assessment of crew aerobic capacity. It analyzes human metabolites, cardiac output, lung diffusing capacity, lung volume, pulmonary function and nitrogen washout. Crewmembers activate the GASMAP hardware and perform a full functional health check every 90 days. On Wednesday, Bowersox conducted the third round of research with the FOOT/Ground Reaction Forces During Space Flight (FOOT) experiment. FOOT is designed to characterize the stress on the bones and muscles in the lower extremities in microgravity. Beginning today, the crew will conduct five days of research with the Renal Stone experiment. The crew is taking potassium citrate pills or a placebo to study a possible preventative for kidney stones in space. The microgravity environment of the Station results in several changes in the human body, including changes in fluid metabolism and bone loss that increase the chance of kidney stone formation during and after flight. As part of the experiment, they collect urine samples and record their food, fluid, exercise and medication to assess environmental influences other than microgravity. Crew Earth Observation crew photography opportunities for today include Buenos Aries, Argentina; the Tuamotu Archipelago, air quality over Southeast Africa, Cape Town and Johannesburg, South Africa, and Patagonian glaciers. On January 28th, the crew and ground controllers are scheduled to begin operations with the Earth Knowledge Acquired by Middle School Students (EarthKAM) experiment for Expedition Six. The Payload Operations Center at NASA's Marshall Space Flight Center in Huntsville, AL, manages all science research experiment operations aboard the International Space Station. The center is also home for coordination of the mission-planning work of a variety of international sources, all science payload deliveries and retrieval, and payload training and payload safety programs for the Station crew and all ground personnel. Contact: Steve Roy NASA/MSFC Huntsville, AL Phone: 256-544-0034 ________________________________________________________________________ MARS ODYSSEY THEMIS IMAGES NASA/JPL/ASU release 21-24 January 2003 Layered Deposits in Western Candor Chasma (Released 21 January 2003) http://themis.la.asu.edu/zoom-20030121a.html Erosion Effects (Released 22 January 2003) http://themis.la.asu.edu/zoom-20030121a.html Dust avalanches (Released 23 January 2003) http://themis.la.asu.edu/zoom-20030123a.html Concentric Crater Fill (Released 24 January 2003) http://themis.la.asu.edu/zoom-20030124a.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 24 January 2003 Stardust's navigation camera took images this week for evaluating performance of the periscope. Images of the Pleiades star cluster were taken using a series of one-degree steps in positioning the periscope mirror. The images will be transmitted to Earth within the next two weeks. The spacecraft is operating in good health. It had one period of radio contact with Earth this week through NASA's Deep Space Network. The Stardust team has made minor updates in the mission's telemetry dictionary and flight rules to incorporate lessons learned from the flyby of asteroid Annefrank last November. 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 4.