MARSBUGS: The Electronic Astrobiology Newsletter Volume 10, Number 17, 28 April 2003. Editor/Publisher: David J. Thomas, Ph.D., Science Division, Lyon College, Batesville, AR 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://welcome.to/marsbugs or http://www.lyon.edu/webdata/users/dthomas/marsbugs/. ________________________________________________________________________ CONTENTS 1) MARSIS: SUBSURFACE SOUNDING RADAR/ALTIMETER ESA release 2) SEDIMENT CORES YIELD OLDEST DNA YET DISCOVERED By Sarah Graham 3) NASA TO PARTNER WITH FOOTHILL-DE ANZA COMMUNITY COLLEGE DISTRICT NASA/ARC release 03-30AR 4) A UK FLOTILLA TO STUDY EARTH-GRAZING ASTEROIDS From SpaceDaily 5) LIFE AND DEATH FROM SPACE From SpaceDaily 6) EVALUATING THE THREAT FROM EARTH'S RADIATION BELTS From SpaceDaily 7) ARECIBO DIARIES (3): TRAVELING ON A HIGH-TECH SHIP OF DISCOVERY By Seth Shostak 8) BEAGLE POINTS TO MARS From Astrobiology Magazine 9) TITAN REVEALS A SURFACE DOMINATED BY ICY BEDROCK By Lori Stiles 10) ARECIBO DIARIES (4): IS THE SEARCH WISHFUL THINKING OR HUBRIS? By Seth Shostak 11) GREEN GENERATIONS By Tony Phillips 12) REDUNDANT EVOLUTION By Leslie Mullen 13) NEW ADDITIONS TO THE ASTROBIOLOGY INDEX By David J. Thomas 14) CONTINUING COVERAGE OF THE COLUMBIA DISASTER By David J. Thomas 15) CASSINI SIGNIFICANT EVENTS NASA/JPL release 16) MARS EXPLORATION ROVERS: SPACECRAFT AND EXPENDABLE VEHICLES STATUS REPORT By George H. Diller 17) MARS GLOBAL SURVEYOR IMAGES NASA/JPL/MSSS release 18) MARS ODYSSEY THEMIS IMAGES NASA/JPL/ASU release 19) STARDUST STATUS REPORT NASA/JPL release ________________________________________________________________________ MARSIS: SUBSURFACE SOUNDING RADAR/ALTIMETER ESA release April 2003 The search for water There's plenty of evidence that water once flowed freely on the surface of Mars. Today, however, we know for sure that it exists only in the thin martian atmosphere as wisps of vapor, which occasionally condenses out as ice at the winter poles. Recent results from Mars Global Surveyor (MGS) suggest that liquid water may still occasionally bubble up from underground (see news story Water discovery gives new impetus to Mars Express) but if so, it doesn't remain on the surface for long. So where did the quantities of water from early times go? Much has probably been lost to space with the martian atmosphere, which has thinned enormously over the past 3.8 billion years. Several of the experiments on board Mars Express will be looking for mechanisms to explain this atmospheric loss. Many planetologists, however, believe that a lot of water must still be on Mars, locked into frozen or liquid underground reservoirs and the recent MGS results support this view. MARSIS (Mars Advanced Radar for Subsurface and Ionospheric Sounding) will set out to map underground water and ice. The instrument is a type of ground penetrating radar. On Earth, such radar is typically operated from the ground or from aircraft to prospect for water or man-made objects a few tens of meters below ground. On Mars, it will search for water up to 5 km below ground from its vantage- point on board Mars Express. "Spaceborne ground penetrating radar sounding has been attempted only once before, in a successful experiment during one of the Apollo lunar missions. Marsis will be the first such radar to look for underground water. It is unique," says Giovanni Picardi, MARSIS Principal Investigator from the University of Rome "La Sapienza", Italy. MARSIS will send low frequency radio waves (1.3-5.5 MHz) towards the planet from a 40 m long antenna which will be unfurled after Mars Express goes into orbit. The entire instrument including antenna and data processing unit weighs about 12 kg. "We need such a long antenna so that we can work with long wavelengths, which are able to penetrate Mars for a few kilometers," says Roberto Seu, who is the Deputy Principal Investigator. Sounding the subsurface The radio waves will be reflected from any surface they encounter. For most, this will be the surface of Mars. But because of the low frequency, a significant fraction will travel through the crust to encounter further interfaces between layers of different material. "If there is a layer containing liquid water, it should generate a radar echo," explains Seu. "The presence of weaker signals after the first strong surface return will enable us to detect subsurface interfaces, while the time delay between the two signals will allow us to measure the depth of the interfaces," adds Picardi. By sending two different frequencies at the same time and analyzing the echoes generated, MARSIS will be able to extract information on the electrical properties of the reflecting surface and hence its composition. "An underground zone of liquid water will have very different electrical properties from the surrounding rocks and it will reflect very strongly," says Jeff Plaut, the Co-PI from the Jet Propulsion Laboratory in Pasadena, California, US. "We should be able to see the top of a liquid zone somewhere in the upper 2-3 km fairly easily. If other conditions are favorable, we may be able to go down to 5 km or more." The radio waves will be reflected at any interface, not just that between rock and water, so MARSIS should reveal much about the composition of the top 5 km of crust in general. It should, for example, pick out layers of rock interspersed with ice, which are more likely to exist close to the martian surface than liquid water. "We should be able to measure the thickness of sand deposits in sand dune areas, or determine whether there are layers of sediment sitting on top of other material in areas hypothesized to be the sites of ancient lakes or oceans," says Plaut. "We may even see the boundaries between different lava flows." The best ground penetrating studies are made during night when the martian ionosphere is least active and when the spacecraft is less than 800 km from the martian surface, a condition that occurs for 26 minutes during each 6.75 hour orbit. During the lifetime of the mission, the instrument will be able to conduct ground penetrating studies over the entire planet. Sounding the ionosphere During the day, sunlight ionizes the upper atmosphere (charges it up electrically) and long wavelength radio waves bounce off it. Those that are reflected from the ionosphere can reveal much about its structure. MARSIS will measure the electron density in the ionosphere and hence quantify the effect of charged particles streaming out from the Sun (the solar wind) on the upper atmosphere. Such measurements will complement those of other instruments whose prime task is to find out whether the unremitting depredations of the solar wind over billions of years have stripped Mars of much of its atmosphere (see ASPERA). For the first 100 days of the mission, however, the orbit will be lower than 800 km during the daytime only. MARSIS will take this opportunity to sound the subsurface at the higher end of its frequency range, study the ionosphere and perform instrument calibrations. This involves measuring the return echoes sent back from the surface only in order to get reliable readings during sounding operations. Once the calibration is complete, dayside subsurface and ionospheric soundings will continue for the remainder of the 100 days. Exploring the south pole and layered terrain For the following 200 days, the lowest part of Mars Express's orbit will occur during night in the southern hemisphere. "This should allow MARSIS to make some very interesting observations of the south polar cap and the surrounding layered terrain," says Plaut. MARSIS will work well wherever the material in the martian crust is organized into layers. Recent images taken by NASA's Mars Global Surveyor spacecraft show layering in many regions of the planet. But the poles have long been famous as the regions of layered terrain (see poles) and many planetologists believe that the layers may hold clues to the history of climate change on Mars. NASA's ill-fated Mars Polar Lander would have explored this region if it had landed successfully. MARSIS, on board Mars Express, shows promise of making up for at least some of the loss. Over subsequent days, optimal conditions for ground penetrating studies will occur over different regions of the martian surface, allowing MARSIS to build up a three dimensional picture of the upper layers of the entire martian crust over the mission's lifetime. "We know water is present as ice at the poles and we think ice is present in the crust. It should occur near the surface at the poles and somewhat deeper at the equator. In fact, it may be present almost everywhere," says Seu. MARSIS will be the first instrument on any spacecraft to really test the validity of some of our ideas about water on Mars. Further information is available at http://www.marsis.com. Read the original article at http://sci.esa.int/content/doc/9b/21915_.htm. An additional article on this subject is available at http://www.spacedaily.com/news/mars-water-science-03g.html. ________________________________________________________________________ SEDIMENT CORES YIELD OLDEST DNA YET DISCOVERED By Sarah Graham From Scientific American 18 April 2003 Researchers have retrieved from sediment cores plant DNA that is nearly 400,000 years old--the oldest such specimen ever recovered. Analysis of the ancient genetic material should help scientists paint a more detailed picture of prehistoric landscapes. Eske Willerslev of the University of Copenhagen and his colleagues collected sediment samples from the Siberian tundra in search of ancient bacterial DNA. To their surprise, they instead discovered DNA from 28 different families of trees, shrubs, herbs and mosses. What is more, the soil samples also contained DNA from eight types of mammals, both of species that survive today and ones that disappeared long ago, such as the wooly mammoth. Read the full article at http://www.sciam.com/article.cfm?chanID=sa003&articleID=000DFC3D-1546- 1E9F-A9B3809EC588EEDF. ________________________________________________________________________ NASA TO PARTNER WITH FOOTHILL-DE ANZA COMMUNITY COLLEGE DISTRICT NASA/ARC release 03-30AR 21 April 2003 NASA and the Foothill-De Anza Community College District are signing a planning agreement tomorrow to facilitate the development of an academic center in NASA Research Park for first-generation college students interested in pursuing careers in science, technology, engineering and education. The college district's plan includes offering academic programs at NASA to prepare students for information technology, astrobiology and the life sciences, engineering, mathematics and physical sciences. "This agreement will bring community college students in high-tech career paths to classrooms and labs onsite at NASA Ames," said Dr. Adena Loston, associate administrator for education at NASA Headquarters. "This partnership advances the goal of the new NASA Education Enterprise, to inspire more students to study science, technology, engineering and mathematics, with the ultimate goal of having them choose careers in aeronautics and space at NASA. This next generation of explorers will learn what it takes to develop the technologies of tomorrow, through unique teaching and lab experiences, provided as only NASA can." she said. "We are delighted to sign this agreement and look forward to working with the Foothill-De Anza Community College District as they embark on this exciting project," said G. Scott Hubbard, director of NASA Ames Research Center. "NASA is committed to working hand in hand with teachers and academic institutions to enhance educational opportunities and programs, to provide access to unique NASA products, learning materials, facilities and researchers, and to inspire the next generation. The new center is an excellent way for us to work collaboratively to accomplish these important goals," he said. "It is indeed a pleasure to be signing this agreement today," said Dr. Lois A. Callahan, interim chancellor of the Foothill-De Anza Community College District. "Even though we are all experiencing these extraordinarily difficult economic times, we must look to the future. Working with NASA to plan a first-class educational center at the NASA Research Park will move us forward as our economy recovers," she said. "By collaborating with NASA and other partners of the NASA Research Park, we are excited to plan for a new vision of higher education in Silicon Valley," said Dr. Bernadine Chuck Fong, president of Foothill College. "To make a difference in the lives of Silicon Valley students historically underrepresented in higher education, De Anza College is proud to partner with NASA and our local high schools to provide new educational models to give our students the math, science and technology skills they must have to be successful in our new economy," said Dr. Martha J. Kanter, president of De Anza College. The Foothill-De Anza Community College District was founded in 1957 to serve residents of Cupertino, Los Altos, Los Altos Hills, Mountain View, Palo Alto, Sunnyvale and portions of Santa Clara and San José. The district also serves as the primary high school-to-community college link to the Fremont Union, Mountain View-Los Altos Union and Palo Alto Unified high school districts. District officials say the challenge of the 21st century includes the need to serve a growing and diverse student population. Since 1957, Foothill-De Anza has responded to the needs of more than one million students who have enrolled in its day, evening, off campus and online courses. The innovative workforce that has transformed the Silicon Valley is comprised of more than 500,000 former Foothill-De Anza students. Located on 213 acres at Moffett Field, NASA Research Park is envisioned as a world-class, shared-use research and development campus in association with academia, industry and non-profit organizations. NASA Ames has a vibrant education outreach program, hosting many events onsite and delivering NASA education materials to classrooms nationally. NASA Ames is partnering with organizations to conduct research in astrobiology, nanotechnology, information technology and other aerospace-related research areas. For more information about NASA Research Park on the internet, visit http://researchpark.arc.nasa.gov. Contacts: Michael Mewhinney NASA Ames Research Center, Moffett Field, CA Phone: 650-604-3937 or 650-604-9000 E-mail: Michael.Mewhinney@nasa.gov Marisa Spatafore Foothill-De Anza Community College District, Los Altos Hills, CA Phone: 650-949-6100 E-mail: spataforemarisa@fhda.edu Kurt Hueg Foothill College, Los Altos Hills, CA Phone: 650-949-7645 E-mail: huegkurt@foothill.edu Terri O'Connor De Anza College, Cupertino, CA Phone: 408-864-8672 E-mail: oconnorterri@deanza.edu ________________________________________________________________________ A UK FLOTILLA TO STUDY EARTH-GRAZING ASTEROIDS From SpaceDaily 22 April 2003 On 30 June 1908, the seemingly endless forests of Siberia received an unwelcome and unexpected visit by an intruder from deep space. As it plunged headlong through the Earth's atmosphere, the incoming asteroid exploded a few miles above the tree tops, flattening the forest over an area about 50 km (30 miles) in diameter. If the 60 meter (200 ft) wide chunk of rock had arrived a few hours later, it could have destroyed a city the size of London or Paris. Exactly how many of these threatening objects are lurking unseen in the depths of the Solar System no one knows, but scientists estimate that events such as Tunguska occur on average once every 200 years. Larger objects arrive less frequently but pack a much greater punch. How can we find out more about these Near Earth Objects (NEOs) and possibly find a way of preventing them from sending the human race the way of the dinosaurs? One way is to send spacecraft to study them at close range. At the UK/Ireland National Astronomy Meeting in Dublin, Simon Green (Open University) described SIMONE (Smallsat Intercept Missions to Objects Near Earth), a UK-led proposal to launch a fleet of low-cost microsatellites that will individually rendezvous with different types of Earth-grazing asteroids. This would be the first interplanetary microsatellite mission. Read the full article at http://www.spacedaily.com/news/asteroid- 03d.html. ________________________________________________________________________ LIFE AND DEATH FROM SPACE From SpaceDaily 22 April 2003 Ever since its formation at the birth of the Solar System, some 4570 million years ago, planet Earth has resembled a giant bulls-eye in space, a target for asteroids and comets of all shapes and sizes. Clearly, this violent history has influenced the planet's surface and atmosphere, as well as the evolution of life. Some impactors bring water and organic compounds, ingredients that may have been the building blocks of life. Other, more massive, bodies may arrive in a blaze of fire and fury, the results of their impacts being death, destruction and extinction. Meanwhile, with the discovery of planets orbiting other stars, we must also assess their potential as impact targets. On Wednesday 9 April, five experts in the study of asteroids, comets and impacts explained to the UK/Ireland National Astronomy Meeting in Dublin their ideas about the effects on the Earth and other planets of bombardment by extraterrestrial objects. The convenor of the session was Dr. Monica M. Grady (Natural History Museum, London). Read the full article at http://www.spacedaily.com/news/early-earth- 03b.html. ________________________________________________________________________ EVALUATING THE THREAT FROM EARTH'S RADIATION BELTS From SpaceDaily 22 April 2003 Near-Earth space can be a very dangerous place for both astronauts and satellites. One of the most hazardous environments is the van Allen belts, a doughnut-shaped region, filled with trapped energetic particles, which surrounds the Earth. These particles can damage spacecraft electronics and are one of the main factors that limit the lifetime of commercial spacecraft on orbit. Scientists have known about the existence of these radiation belts for more than four decades, but their inner workings still remain something of a mystery. Now new research by Dr. Richard Horne of the British Antarctic Survey and collaborators at UCLA and University College London--Mullard Space Science Laboratory is revealing what happens during space storms, 12,000 miles (19,200 km) above the Earth, and opening the door to discovering how damage to satellites may be reduced. Read the full article at http://www.spacedaily.com/news/radiation- 03c.html. ________________________________________________________________________ ARECIBO DIARIES (3): TRAVELING ON A HIGH-TECH SHIP OF DISCOVERY By Seth Shostak From Space.com 22 April 2003 The guts of any SETI experiment lie coiled within its digital signal processors. Deep inside these unimposing aluminum boxes, herds of electrons shuttle back and forth at the command of circuitry and software, sorting the incoming cosmic static by frequency, and hunting for the faint, slowly varying tone of distant transmitters. For more than a decade, Project Phoenix has used digital signal processors originally built for NASA's SETI search--the one that was halted in 1993. Sure, we've improved these devices a great deal, but in the digital world, a hardware design that's a dozen years old is museum fodder. The world has turned. The old processor, known to its pals as the Targeted Search System (TSS), is still around, hunkered down in a tractor-trailer container parked outside the observing room. There was so much electronics in this baby that the trailer required 38 kilowatts of full-time air conditioning just to keep the chips cool and calculating. But we use something different now--a new, modular system that is rather straightforwardly called the New Search System (NSS). Read the full article at http://www.space.com/searchforlife/shostak_arecibo_3_030422.html. ________________________________________________________________________ BEAGLE POINTS TO MARS Based on ESA mission data From Astrobiology Magazine 23 April 2003 The Beagle 2 project is the British-led effort to land on Mars as part of the European Space Agency's Mars Express Mission to be launched in June 2003. As a result of the relative positions of Mars and Earth in 2003, a launch during this window offers the shortest journey, the minimum transit time, allowing the maximum payload with the reduced fuel requirements. With a landed mass of less than 30 kilograms (66 lbs), Beagle 2 represents the most ambitious mass ratio for a science payload-to-system combination ever attempted. Almost a third of the payload will carry out various types of analysis or be used to manipulate and collect samples for study on the surface of Mars. The probe's primary mission life is 180 martian days (Sols; 1 martian year equals 687 Earth Days). An extended mission could go on for three times that initial duration. The lander destined for Mars will carry the instruments necessary to search for the signatures of life; its name, Beagle 2, commemorates Charles Darwin's ship and the voyage which he called "the most important event in my life". The project seeks in situ evidence of organic matter, associated with features and minerals related to flowing water. In choosing the Beagle 2 landing site, special attention was given to finding locations where the harsh oxidizing environment has been prevented from destroying the evidence. Such a place will be within the interiors of rocks or in the soil shielded by large boulders. Springtime on Mars Beagle 2's target for landing on Mars will be a region which shows evidence of having been inundated by large volumes of water. The landing site is centered near 11°N, 270°W, in eastern Isidis Planitia. The name, Isidis Planitia, refers to the broad, relatively flat plain that covers the floor of an extremely ancient, large basin formed by an asteroid or comet impact perhaps more than 4 billion years ago. As the third largest impact basin, its floor exhibits chains of pitted ridges, numerous smaller meteor impact craters, and a variety of light-toned ripples and small dunes. The number of rocks on the surface seems to be about right--not too many to threaten a safe landing, but enough to provide an interesting landscape for the experiments. The region seems to be a sedimentary basin where traces of life could have been preserved. Other criteria than the likely presence of ancient water are the altitude and latitude on Mars. Too high and there is insufficient atmospheric density to allow the Beagle 2 parachutes to slow the lander for a safe touch down. Both height and also too far north or south away from the equator will increase the need for additional thermal protection as the climate worsens. The northern hemisphere was a favored destination because in the martian lowlands the planet will be coming from spring into summer during the time Beagle is working in 2004. "This is the best site given the landing constraints and scientific aims of Beagle 2," said John Bridges from the Natural History Museum, London, who has been assessing several sites on behalf of the project. Controlled collision Like the mission plan for the 1997 Mars Pathfinder, the critical landing of Beagle 2 features a set of steps compared to a controlled collision. When the lander first encounters the martian atmosphere, it will be traveling at more than 20,000 km/hr (12,000 mph). Fortunately the probe has a clamshell protective armor, and also parachutes and airbags to cushion its rapid impact. The clam-like structure of Beagle 2 not only has to support all the elements required to carry out the scientific mission on the surface of Mars but must also ensure they survive the final impact of landing. When Beagle 2 drops onto Mars out of its cocoon of gas-filled bags, the impact could be in any orientation with a contact area varying from a small, sharp rock to a large, flat surface. The design case is equivalent to pushing your PC off a chair (on Earth) onto a concrete floor and expecting it still to work. Unfortunately Beagle 2 does not have the full choice of materials available to your PC manufacturer because it has to be as light as possible to maximize the payload inside the lander and to keep the systems warm through the martian night when temperatures down to -70°C will be reached. One energy saving protocol was to carry out those experiments which generate heat within the lander during the night so that the energy dissipated helps to keep the lander warm--a martian off-peak heating strategy. The landing solution chosen was to use an outer shell to absorb impact energy and also thermal insulation within a casing that must spread the impact loads and resist tearing. An inner shell comprising carbon-fiber skins on an aluminum honeycomb core makes up the primary structure. All materials have to be compatible with more than the usual space environment (vacuum and radiation exposure, low outgassing, low mass overall, low cost) in that they have to face the sterilization process necessary for planetary protection requirements. The two halves of the lander, lid and base are joined by a spring loaded hinge which irrespective of the orientation which Beagle 2 finds itself on Mars will open the clam in its correct position. When Beagle 2 has landed, its precise position will need to be measured. One way of doing this will be to time the movement of the shadow of Mars's tiny moon, Phobos, as it passes over the lander during a partial eclipse of the Sun. "In February 2004, the Sun will have a partial eclipse by Phobos. By timing the eclipse, we will be able to pinpoint the lander's position quite accurately," said Tom Duxbury from the Jet Propulsion Laboratory, Pasadena, California, who is helping to characterize the landing site using Mars Global Surveyor data. Science on the surface The lander's science targets center on the search for past life, including the: * presence of water * existence of carbonate minerals * occurrence of organic residues * complexity and structure of organic material * isotopic fractionation between organic and inorganic phases. The hoped-for results are based on a plan to: * Seek trace atmospheric species indicative of extant life. * Measure the detailed atmospheric composition to establish the geological history of the planet and to document the processes involved in seasonal climatic changes or diurnal cycling. * Investigate the oxidative state of the martian surface, rock interiors and beneath boulders. * Examine the geological nature of the rocks, their chemistry, mineralogy, petrology and age. * Characterize the geomorphology of the landing site. * Appraise the environmental conditions including temperature, pressure, wind speed, UV flux, oxidation potential, dust environment etc. Seeking all carbon-based life forms In looking for past life, the element carbon is one starting point. So Beagle 2 will heat samples of soil or rock in oxygen. This is equivalent to burning, since all forms of carbon will convert to carbon dioxide via combustion or decompose to a rocky residue (carbonates). The organic matter, if any, will combust. Most important for Beagle 2 is a stepped combustion method--a ramp to higher, then lower temperatures in stages--to resolve between organic and inorganic types of carbon. This should distinguish between possible microbial remains and carbonate minerals. The residue from fossils is enriched in the light carbon, 12C, than what is expected from mineral or ancient sediments alone. Biological processes preferentially use the lighter of two stable isotopes of carbon 12C and 13C. The ratio of the two stable isotopes (isotope scientists use the term delta 13C to describe differences in the ratio) can give a clue to the type of life processes (e.g. photosynthesis to convert light to energy, methanogenesis to convert carbon dioxide to methane) which have resulted in the fractionation. Since strong chemical reactions quickly destroy (oxidize) methane at the martian surface, if methane is found today, there must be some replenishment that gives a clue to active biology. Biosynthesis leaves a ubiquitous signature of life even in specimens where there are no fossils visible. If evidence for life is below the exposed surface of Mars, then Beagle 2 will try to dig using a mole-like sample retriever. It is expected that the mole will be able to crawl up to three meters (around 9 feet) away from the lander, including the burrowing phase. Samples will be collected using the mole from below the harsh oxidizing surface, the best location being a region additionally protected by a boulder large enough not to have been disturbed since being emplaced. What's next? Mars Express will be launched by a Soyuz-Fregat launcher from the Baikonur Cosmodrome in Kazakhstan in June 2003. Customs formalities were recently cleared in Moscow and the lander arrived at the airport in Baikonur on March 20th. The Beagle 2 Probe was then transported by rail to the spacecraft assembly complex to be mated once more with the Mars Express spacecraft and prepared for launch. Once launched, the spacecraft will take six months to reach the Red Planet. Read the original article at http://www.astrobio.net/news/article437.html. ________________________________________________________________________ TITAN REVEALS A SURFACE DOMINATED BY ICY BEDROCK By Lori Stiles University of Arizona release 24 April 2003 Scientists who have peered through the smoggy orange haze of Saturn's largest moon, Titan, have discovered that the surface is not entirely covered by liquid and solid organic materials that rain out of the atmosphere. Extensive areas of icy bedrock lie exposed on Titan's surface, they report in today's issue of Science (April 25, 2003). "Titan's surface reflectivity looks a lot like that of Jupiter's moon, Ganymede. This is somewhat surprising because Titan is believed to have a lot of organic gook on its surface," said Caitlin A. Griffith of the University of Arizona Lunar and Planetary Laboratory. Titan's atmosphere, ten times as massive as Earth's, is primarily nitrogen laced with such poisonous substances as methane and ethane. Titan is thickly veiled by a dense hydrocarbon haze that forms in the high stratosphere as atmospheric methane is destroyed by sunlight. The haze is much thicker than Earth's worst city smog. It was impenetrable to cameras aboard the Pioneer and Voyager spacecraft that flew by the Saturn system in the late 1970s and early 1980s. The by-products of methane molecules destroyed in the sun's ultraviolet light react with other molecules in Titan's atmosphere, forming organic droplets and particulates that fall onto the moon's surface, blanketing the icy bedrock and forming lakes and oceans. UA planetary scientist Jonathan Lunine and others theorize that atmospheric methane is replenished on Titan in a liquid cycle similar to Earth's hydrologic cycle. Others theorize that Titan's methane is produced by geologic activity. Scientists have measured and modeled the rate of methane photolysis, and from that deduced how much material annually settles out of the atmosphere. "Assuming that Titan's atmosphere has existed over the moon's 4.6 billion year lifetime, 800 meters of sediments would lie on the surface," she said. "So one might ask whether the surface is covered with the liquid and the solid sediments, such that we can't see the ice and rock that exist beneath." Since 1991, Griffith and others have developed and used a technique that allows observers to spectroscopically view the surface at several narrow infrared "windows," or regions between the very thick methane bands. On this project, the team used the United Kingdom Infrared Telescope and NASA's Infrared Telescope Facility, both on Mauna Kea, Hawaii, to observe at eight near-infrared windows. Griffith, Tobias Owen of Hawaii's Institute for Astronomy, Thomas R. Geballe of the Gemini Observatory, John Rayner of Hawaii's Institute for Astronomy, and Pascal Rannou of the Pierre and Marie Curie University in Paris conclude after analyzing surface reflectivity that much of Titan's surface is exposed icy bedrock. "Titan's spectra resemble Ganymede's spectrum, dominated by ice features," they report. Images from UA planetary scientist Peter Smith, who used the Hubble Space Telescope in 1994 to get the first image of Titan's surface, and images from others since show that Titan has large patches of darker terrain, Griffith noted. "It's not clear what the darker material is, but one possibility is that it is these organic liquids and sediments. The images, taken together with our results, suggest that organic stuff is moved around on the surface in such a way as to expose bedrock ice." The new findings are indirectly relevant to the NASA/ESA Cassini mission/Huygens probe to arrive at Saturn in July 2004, Griffith noted. Scientists would like a better idea of how optically thick Titan's haze is, and how bright or dark its surface will be, to calculate camera exposure times. In addition, scientists are fine tuning their questions as they plan the Cassini observations. Cassini spacecraft instruments include the Visual and Infrared Mapping Spectrometer (VIMS), an experiment headed by Robert H. Brown of the UA Lunar and Planetary Lab. The orbiter-borne instrument will map large chunks of Titan's surface at optimal haze-penetrating, near-infrared wavelengths. Griffith is working with the VIMS science team. Contact: Caitlin A. Griffith Phone: 520-626-3806 E-mail: griffith@lpl.arizona.edu Lori Stiles UA News Services Phone: 520-621-1877 Read the original news release at http://uanews.opi.arizona.edu/cgi- bin/WebObjects/UANews.woa/wa/MainStoryDetails?ArticleID=7248. Additional articles on this subject are available at: http://www.astrobio.net/news/article442.html http://spaceflightnow.com/news/n0304/26titan/ ________________________________________________________________________ ARECIBO DIARIES (4): IS THE SEARCH WISHFUL THINKING OR HUBRIS? By Seth Shostak From Space.com 24 April 2003 Sometimes I feel like an ant. Actually, that syntax implies that I might have a hankering for some chocolate-covered formicidae, but that's not right. What I mean to say is that sometimes--usually after dinner, it seems--my mind zooms back in hope of seeing the big picture: trying to get the "establishing shot" on life, SETI, and just what the heck we're doing here in the lush foliage of Puerto Rico. And the first jarring revelation afforded by this wide-angle view is that we're just ants. There have been ten thousand generations of Homo sapiens before us. Since it's a fairly good rule of science to assume that anything you observe is typical (until shown otherwise), there may be ten thousand generations to follow. This is like the ants in my backyard. Those segmented little beasts are only one rank of marchers in a parade of time that stretches dauntingly backwards and forwards. Sure, they think they're special. They eagerly do their "ant thing," hauling foodstuffs back to the nest in long, organized lines. But really, they're no more special than their great- great-great-great (put in one thousand "greats" here) grand-ants, or the countless ants to follow. It seems pretty analogous to the human condition, but not entirely. For SETI, we figure our generation really is special. Ours is the generation that--either at this observatory or some other--will break step with the parade and finally shatter the bubble of isolation that has enclosed life on this planet for 3.5 billion years. Read the full article at http://www.space.com/searchforlife/shostak_arecibo_4_030424.html. ________________________________________________________________________ GREEN GENERATIONS By Tony Phillips From "Space Station Science Picture of the Day" 24 April 2003 [http://science.nasa.gov/ppod/y2003/images/greenbean_med.jpg] Green generations. Image credit: NASA/ISS expedition 6 crew. It looks like an ordinary pea pod. And it is. That's what so amazing-- because this pod lives in space. It's a traveling companion of Cosmonaut Nikolai Budarin. Every day Budarin tends a growing garden of these peas located within the Russian Lada greenhouse onboard the International Space Station. The peas are part of an experiment to investigate plant development and genetics. "Budarin is working with peas of two types," says principal investigator Dr. Vladimir Sychev of the Institute of Biomedical Problems in Moscow: "a flagellate variety with red flowers (up to 27 cm high) and an acacia-leaf variety with white flowers (up to 20 cm high). Both are dwarf peas from the plant collection of the Moscow University Genetics Department." "The experiment has been going for six weeks," he continues, "and the pea plants have now reached the stage of seed ripening. We expect these seeds to mature in another 2 to 3 weeks. If everything goes as planned, cosmonaut Yuri Malenchenko (the commander of the next space station crew) will plant the space seeds to grow a second generation of space peas." Never before have peas flowered and produced offspring in Earth-orbit. It's an important first because "legumes, including peas, can be used in biological life support systems for spaceships," adds Sychev. They can provide oxygen and food for astronauts and, in tandem with microbes, help purify water and human waste. The ability of such plants to reproduce generation after generation is key for long space voyages. One day there will be generations of people in space, too. These little peas are leading the way. Read the original article at http://science.nasa.gov/ppod/y2003/24apr_greengenerations.htm. ________________________________________________________________________ REDUNDANT EVOLUTION By Leslie Mullen From Astrobiology Magazine 28 April 2003 Redundancy seems to be a factor in evolution, according to a new study published in the journal Nature. University of Georgia geneticist Andrew Paterson has found that blocks of genes in plants have duplicated themselves over time. These "carbon copies" may have led to the development of new plant species. Scientists already knew that many plants contain two or more copies of most genes, but they don't know why these copies exist, or when they became a part of the genome. Paterson and his colleagues studied Arabidopsis thaliana, which has the smallest genome known among flowering plants. Because Arabidopsis is easily grown in the lab, it was the first plant to have its genetic sequence completely determined. About 30 percent of the genes in Arabidopsis are duplicated. Paterson discovered that each time a duplication event occurred, the entire genetic sequence of Arabidopsis doubled. The copies became a functioning part of the plant, but over time, some of the copies were shuffled around or lost. This loss of genes led to many of the differences among modern plants. The scientists compared Arabidopsis genes with genes from plants such as cotton, cauliflower, alfalfa, soybeans, tomatoes, rice, pine trees, and moss. After looking at 22,000 genetic comparisons, the results were pooled. "Breakpoints" indicated duplication events. The study shows that the genetic sequence of Arabidopsis has duplicated at least twice, and perhaps a third time. Squeezing the trigger One of the duplication events occurred sometime between 170 and 235 million years ago. This event may have coincided with the time that dicots diverged from a common ancestor. Dicots are a class of flowering plants (most flowering trees, for instance, are dicots). Paterson says the duplication event that occurred roughly 200 million years ago happened very early in the divergence of dicot plants from common ancestors. Because the event occurred so early in the development of dicots, it affected every plant that resulted from this divergence. What could have caused this genetic duplication to occur? This event appears to closely follow one of the most catastrophic events in life's history: the P/T extinction. This event--marked in the geologic record as the Permian/Triassic boundary--occurred about 250 million years ago. Known as "The Great Dying," up to 96 percent of marine species and about 70 percent of land species were wiped out during this period in Earth's history. Scientists have not been able to determine what caused this cataclysm to life, although theories of asteroid impacts, climatic changes, and the greenhouse effect have all been suggested. There was another duplication event sometime between 15 and 86 million years ago, but it did not affect as many plants--mostly just members of the Brassicales order. This is probably because fewer plants diverged from a common ancestor during this time. This duplication event, too, occurred around the same time as a major extinction event. The Cretaceous-Tertiary (K-T) extinction occurred about 65 million years ago, and is famous for being the event that claimed the dinosaurs. The consensus at present is that this extinction event was triggered by an asteroid impact. Scientists even think they have identified the crater that resulted from this impact--the Chicxulub crater in the Yucatan. It has long been understood that changes in the environment can lead to genetic changes and new species. Still, Paterson does not claim that the duplication of genes in plants has anything to do with mass extinction events. "We've toyed with the possibility of links to P/T or K-T," says Paterson, "but to suggest that such a link exists based on these data would be very speculative at this point." What's next? A third possible duplication event may have occurred prior to the other two events. Paterson plans to do additional analysis of gymnosperms (such as pines) in order to clarify this event. "We are trying to pin down more precisely the timing of the events," says Paterson. "We're also looking at additional plant genomes, such as rice, to better understand how duplication has affected the history of plant evolution." Read the original article at http://www.astrobio.net/news/article444.html. ________________________________________________________________________ NEW ADDITIONS TO THE ASTROBIOLOGY INDEX By David J. Thomas http://www.lyon.edu/webdata/users/dthomas/astrobiology/astrobiology.html 28 April 2003 Astrobiology, exobiology and terraformation articles http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_articles1. html ESA, 2003. Beagle points to Mars. Astrobiology Magazine. SpaceDaily, 2003. The radar search for martian water. SpaceDaily. Human space exploration and microgravity effects articles http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_articles3. html SpaceDaily, 2003. Evaluating the threat from Earth's radiation belts. SpaceDaily. Search for extraterrestrial intelligence (SETI) articles http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_articles4. html S. Shostak, 2003. Arecibo diaries (3): traveling on a high-tech ship of discovery. Space.com. S. Shostak, 2003. Arecibo diaries (4): is the search wishful thinking or hubris? Space.com. Evolutionary biology and chemistry articles http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_articles5. html S. Graham, 2003. Sediment cores yield oldest DNA yet discovered. Scientific American. L. Mullen, 2003. Redundant evolution. Astrobiology Magazine. SpaceDaily, 2003. Life and death from space. SpaceDaily. Planetary protection articles http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_articles6. html SpaceDaily, 2003. A UK flotilla to study earth-grazing asteroids. SpaceDaily. Astrobiology and extreme environments book list http://www.lyon.edu/webdata/users/dthomas/astrobiology/astrobiology_book s.htm National Research Council, 2003. Life in the Universe: An Assessment of U.S. and International Programs in Astrobiology. National Academy Press, Washington, DC. ________________________________________________________________________ CONTINUING COVERAGE OF THE COLUMBIA DISASTER By David J. Thomas 28 April 2003 The investigation of the Columbia tragedy continues to make headlines in both space and general media. I have included (below) a non-exhaustive list of links to recent articles on the subject. http://www.nytimes.com/2003/04/22/science/space/22NASA.html http://www.nytimes.com/2003/04/22/science/22META.html http://www.space.com/missionlaunches/sts107_caib_030423.html http://www.space.com/missionlaunches/dittemore_030423.html http://www.spacedaily.com/news/shuttle-03m1.html http://www.spacedaily.com/news/shuttle-03n1.html http://www.spacedaily.com/news/shuttle-03o1.html http://www.spacedaily.com/news/oped-03zf.html http://www.spacedaily.com/2003/030423195613.0yfra4s9.html http://www.spacedaily.com/2003/030423192854.wbbrctyt.html http://spaceflightnow.com/shuttle/sts107/030420scenario/ ________________________________________________________________________ CASSINI SIGNIFICANT EVENTS NASA/JPL release 17-23 April 2003 The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Wednesday, April 23. 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. The Command and Data Subsystem (CDS) Flight Software (FSW) checkout activities continued this week with Instrument Expanded Block (IEB) exercises for the Ultraviolet Imaging Spectrograph (UVIS), Imaging Science Subsystem (ISS), Visual and Infrared Mapping Spectrometer (VIMS), and Cosmic Dust Analyzer (CDA). Also performed were a CDS Version 9 telemetry mode checkout and a demonstration of the ability to enable and disable critical controllers via sequenced commands. Real time commands were sent to the spacecraft to turn off the UVIS high voltage power supplies, clear Attitude Control high water marks, and clear the CDS error logs. The checkout activities will complete this week with an optical navigation test. A Preliminary Sequence Integration and Validation (PSIV) approval meeting was held for cruise sequence C37. The sequence was approved for uplink at that time so a final (SIV) meeting will not be necessary. The sequence will be uplinked at the end of this week and will begin execution on April 29. A project briefing was held for cruise sequence C38. C38 is designed to be a minimal activity sequence in order to accommodate concurrent ground system verification and validation activities. In addition to activities to be executed during the sequence such as the Saturn orbit insertion demonstration, options were discussed for the Solar Conjunction Experiment and the 30 days of continuous DSN coverage that has been requested for this activity. The Navigation Software Development team delivered a complete engineering set of the Linux based navigation software. In the areas tested so far, significant performance improvement has been observed. The Mission Sequencing Software team obtained project approval for their development plan for the version 9.1 delivery scheduled for mid-July. This delivery will support science planning and sequencing through spring of 2004. The Composite Infrared Spectrometer (CIRS) team has delivered version 2.0.1 instrument flight software to the Project Software Library. 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 EXPLORATION ROVERS: SPACECRAFT AND EXPENDABLE VEHICLES STATUS REPORT By George H. Diller NASA/KSC release 25 April 2003 Mission: Mars Exploration Rovers (MER-1/MER-2) Launch Vehicles: Delta II/Delta II Heavy Launch Pads: 17-A/17-B Launch Dates: June 5/June 25 Launch Times: 2:56:59 PM/12:38:16 AM EDT Good progress has been made in the circuit board rework and the reinstallation on the two Mars rovers. As a result, the launch of MER-A can be moved up by one day on the recovery schedule. Launch is now scheduled for Thursday, June 5. The first reworked telecom support board (TSB) arrived and was installed on MER-2 on April 16. Rover equipment deck (RED) was reinstalled on April 17. MER-2 lander integration was completed on Thursday, April 24. Integration of MER-2 entry vehicle (back shell, heat shield, lander and rover assembly) scheduled to continue through next week. On MER-1, the telecom support board (TSB) was installed on April 18. MER-1 rover and lander base petal final assembly was completed on Thursday, April 24. Rover installation on base petal is in work and scheduled to be completed by the end of next week. Lander air bag scheduled for installation by the end of next week. The mission will have two launch opportunities each day during the launch period, which is scheduled to close on June 19. Arrival at Mars is set for January 4, 2003, regardless of launch date within that period. On Cape Canaveral Air Force Station, first stage and interstage were erected on Wednesday, April 23 for MER-A on Pad 17-A. Second stage erection is currently scheduled for Saturday, April 26 following with fairing installation on April 29. Simulated Flight and Engine Sequence is currently scheduled for May 9. The solid motor erection is scheduled for May 12-14. Contact: George H. Diller NASA Kennedy Space Center Phone: 321-867-2468 ________________________________________________________________________ MARS GLOBAL SURVEYOR IMAGES NASA/JPL/MSSS release 21-25 April 2003 The following new images taken by the Mars Orbiter Camera (MOC) on the Mars Global Surveyor spacecraft are now available. South Polar Ice Cap (Released 21 April 2003) http://www.msss.com/mars_images/moc/2003/04/21/index.html Polar Polygon Patterns (Released 22 April 2003) http://www.msss.com/mars_images/moc/2003/04/22/index.html Utopia Cracks and Polygon (Released 23 April 2003) http://www.msss.com/mars_images/moc/2003/04/23/index.html Buttes South of Cerberus (Released 24 April 2003) http://www.msss.com/mars_images/moc/2003/04/24/index.html Northern Sinus Meridiani Stereo (Released 25 April 2003) http://www.msss.com/mars_images/moc/2003/04/25/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 21-25 April 2003 Crosscutting Grabens (Released 21 April 2003) http://themis.la.asu.edu/zoom-20030421a.html Erosion and wind deposition (Released 22 April 2003) http://themis.la.asu.edu/zoom-20030422a.html Embayment (Released 23 April 2003) http://themis.la.asu.edu/zoom-20030423a.html Is It Snow? (Released 25 April 2003) http://themis.la.asu.edu/zoom-20030425a.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 25 April 2003 Stardust exited its "solar conjunction period" on April 18. Solar conjunction period is the interval of time where the Sun obscures the line of sight between Earth and the spacecraft, making it virtually impossible to transmit radio signals between the two. The Stardust team enjoyed two periods of communications with the spacecraft in the past week. Telemetry relayed from the spacecraft indicates it is healthy and all subsystems continue to operate normally. Information on the relative positions 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. 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 17.