MARSBUGS: The Electronic Astrobiology Newsletter Volume 9, Number 30, 19 August 2002. 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 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/marsbugs.html. _____________________________________________________________________ CONTENTS 1) IN SEARCH OF MOON TREES By Tony Phillips 2) MANNED CHINA SPACE MISSION "JUST AROUND THE CORNER" From Agence France-Presse and SpaceDaily 3) BACTERIA: SURVIVAL IN SIBERIA By Stephen Hart 4) WOULD ET VOTE? THE LIKELIHOOD OF EXTRATERRESTRIAL DEMOCRACY By Douglas Vakoch 5) SPACEWATCH DETECTION OF "LOST" CONTOUR SPACECRAFT From the Spacewatch web site 6) TUNGUSKA--MAKING AN IMPACT AT THE LONDON "CATASTROPHES" CONFERENCE Geological Society of London release 7) GREAT DEBATES PART VI: ENCORE PERFORMANCE From Astrobiology Magazine 8) NEW ADDITIONS TO THE ASTROBIOLOGY INDEX By David J. Thomas 9) CASSINI WEEKLY SIGNIFICANT EVENTS NASA/JPL release 10) CONTOUR MISSION STATUS REPORTS NASA/JPL/JHUAPL releases 11) INTERNATIONAL SPACE STATION SCIENCE OPERATIONS STATUS REPORT NASA/MSFC release 02-202 12) STARDUST STATUS REPORT NASA/JPL release _____________________________________________________________________ IN SEARCH OF MOON TREES By Tony Phillips From NASA Science News 13 August 2002 Scattered around our planet are hundreds of [organisms] that have been to the Moon and back again. None of them are human. They outnumber active astronauts 3:1. And most are missing. They're trees--"Moon Trees." NASA scientist Dave Williams has found 40 of them and he's looking for more. "They were just seeds when they left Earth in 1971 onboard Apollo 14," explains Williams. "Now they're fully grown. They look like ordinary trees--but they're special because they've been to the Moon." How they got there and back is a curious tale. It begins in 1953 when Stuart Roosa parachuted into an Oregon forest fire. He had just taken a summer job as a US Forest Service "smoke jumper," parachuting into wildfires in order to put them out. It was probably adventure that first attracted Roosa to the job, but he soon grew to love the forests, too. "My father had an affinity for the outdoors," recalls Air Force Lieutenant Colonel Jack Roosa, Stuart's son. "He often reminisced about the tall Ponderosa pine trees from his smoke jumping days." Thirteen years later, NASA invited Roosa, who had since become an Air Force test pilot, to join the astronaut program. He accepted. Roosa, Ed Mitchell and Al Shepard eventually formed the prime crew for Apollo 14, slated for launch in 1971. "Each Apollo astronaut was allowed to take a small number of personal items to the Moon," continued Jack. Their PPKs, or Personal Preference Kits, were often filled with trinkets--coins, stamps or mission patches. Al Shepard took golf balls. On Gemini 3, John Young brought a corned beef sandwich. "My father chose trees," says Jack. "It was his way of paying tribute to the US Forest Service." The Forest Service was delighted. "It was part science, part publicity stunt," laughs Stan Krugman, who was the US Forest Service's staff director for forest genetics research in 1971. "The scientists wanted to find out what would happen to these seeds if they took a ride to the Moon. Would they sprout? Would the trees look normal?" In those days biologists had done few experiments in space; this would be one of the first. "We also wanted to give them away as part of the Bicentennial celebration in 1976." Krugman himself selected the varieties: redwood, loblolly pine, sycamore, Douglas fir and sweetgum. "I picked redwoods because they were well-known, and the others because they would grow well in many parts of the United States," he explained. "The seeds came from two Forest Service genetics institutes. In most cases we knew their parents (a key requirement for any post-flight genetic studies)." On January 31, 1971, Apollo 14 blasted off. Only Shepard and Mitchell actually walked on Moon. On February 5th they landed the lunar module Antares in Fra Mauro--a hilly area where Shepard famously launched his golf balls using a geology tool as a makeshift driver. Roosa remained in orbit as pilot of the mission's command module Kitty Hawk. Inside his PPK was a metal cylinder, 6 inches long and 3 inches wide, filled with seeds. Together they circled the Moon 34 times. Apollo 14 was a success. Scientists were delighted with the mission's geology experiments and they were eager to study the 43 kg of Moon rocks collected by Shepard and Mitchell. Krugman was just as eager to study the seeds. "We had a bit of a scare," Krugman recalls. During decontamination procedures, the seed canister was exposed to vacuum and it burst. The seeds were scattered and traumatized. "We weren't sure if they were still viable," he says. Working by hand, Krugman carefully separated the seeds by species and sent them to Forest Service labs in Mississippi and California. Despite the accident, nearly all of them germinated. "We had [hundreds of] seedlings that had been to the Moon!" Thirty-one years later, Krugman still sounds excited. During the years that followed, the trees thrived as scientists watched. "The trees grew normally," he continued. "They reproduced with Earth trees and their offspring, called half-Moon trees, were normal, too." (He notes, however, that DNA analysis wasn't routinely done in the early '70's, and so the Moon trees weren't tested in that way. There might be subtle differences yet to be discovered.) Finally, in 1975, they were ready to leave the lab. "That's when things got out of hand," he says. Everyone wanted a Moon tree. In 1975 and '76, trees were sent to the White House, to Independence Square in Philadelphia, to Valley Forge. "One tree went to the Emperor of Japan. Senators wanted trees to dedicate buildings. We even did some plantings in New Orleans because the mayor there, Mayor Moon, wanted some," says Krugman. There were so many requests that "we had to produce additional seedlings from rooted cuttings of the original trees." No one kept systematic records, notes Dave Williams. That's why the whereabouts of the trees today are mostly unknown. One of the them went to a Girl Scout camp in Cannelton, Indiana, where 3rd grade teacher Joan Goble found it in 1996. (She knew it was a Moon Tree because a sign said so. Most Moon trees were planted with ceremony; there's usually a sign or plaque nearby that identifies them.) "My students love it," she says. "It looks like an ordinary tree, but they feel it's special anyway because of its trip to the Moon." Jack Roosa has since become a pen pal of Goble's class, encouraging the students to explore and learn as his father did. When Goble contacted Dave Williams to ask for more information about Moon trees, "I was clueless," Williams admits. Like many people who were young in the 1970's, Williams had never heard of such trees, but he soon became an enthusiast. "I found one Moon tree right here at Goddard near my office," he laughs. "I had no idea it was there." Often that's how they're encountered--by accident. Williams now maintains a web site listing all known Moon trees (http://nssdc.gsfc.nasa.gov/planetary/lunar/moon_tree.html). If you stumble across one, contact Dave. He'll investigate the find and add it to the collection if it's authentic. Moon trees are long-lived, adds Krugman. The redwoods could last thousands of years, and the pines have a life expectancy of centuries. Indeed, they've already outlived Stuart Roosa and Al Shepard--two of the humans who took them to the Moon. Says Jack, "I think my father always knew that these trees would serve as a long-lasting, living reminder of mankind's greatest achievement--the manned missions to the Moon." Of course, if humans don't return soon, Moon trees could become the only living things on our planet that have been to the Moon. That's probably not what Stuart had in mind. Jack, however, is optimistic: "These trees will be here 100 years from now," he says. "By then I believe we'll be planting Mars trees right beside them." Additional information on this article is available at http://science.nasa.gov/headlines/y2002/13aug_moontrees.htm?list68322 3. An additional article on this subject is available at http://www.space.com/scienceastronomy/moon_trees_020815.html. _____________________________________________________________________ MANNED CHINA SPACE MISSION "JUST AROUND THE CORNER" From Agence France-Presse and SpaceDaily 14 August 2002 China expects to launch the fourth mission of its fledgling space program before the end of the year, meaning a manned space flight could be "just around the corner", state press said Wednesday. The Shenzhou IV (Divine Vessel IV) craft should follow hot on the heels of March's successful Shenzhou III mission, senior space officials told the China Daily. "We have intensified development of the Shenzhou IV and its carrier rocket, which we plan to launch some time in the remaining months of the year," Zhang Qingwei, head of the China Aerospace Science and Technology Corp., told the paper. If the fourth mission was a success, "a manned space mission would be just around the corner", a separate source close to China's space program told the English language daily, which splashed the news across its front page. Get the full story at http://spacedaily.com/news/020814042606.cq8f0k7a.html. _____________________________________________________________________ BACTERIA: SURVIVAL IN SIBERIA By Stephen Hart From Astrobiology Magazine 14 August 2002 The concept of suspended animation supports the plots of dozens of science fiction books and movies. If such a procedure could ever work with humans, it's surely many decades away. But exobiologists count on suspended animation as one of the best chances of finding life on other planets, Mars specifically. This spring, Gene D. McDonald and colleagues gave them some solid reasons for hope: evidence that single-celled organisms such as bacteria, archaeans and fungi repair cellular damage for tens of thousands of years--and perhaps many times longer--after being frozen solid. Scientists have known for nearly a century that microorganisms can survive in the Siberian permafrost. How they do this, however, is not fully understood. McDonald's discovery hinges on the fact that, even in permafrost, animation turns out to be not quite completely suspended. Even when all life processes appear to have stopped, processes that affect life do not. Organisms frozen in soil continue to be bombarded by radiation from elements within the soil itself. And at any temperature above absolute zero, all molecules vibrate a little. Thus, cells' DNA and other important molecules continue to sustain life-threatening damage. For organisms to remain viable for long periods of time, they must somehow maintain a minimal level of molecular repair. "One of the reasons we did this work is because it had been believed that the organisms that had been buried in permafrost for tens of thousands or hundreds of thousands of years were basically inactive metabolically," McDonald says. But, he wondered, if they remained completely inactive, how much radiation damage could the cells sustain? To answer that question, McDonald and his colleagues, Karen Brinton and Alexandre Tsapin, both working with him at Jet Propulsion Laboratory in Pasadena, and David Gilichinsky, of the Russian Academy of Sciences in Pushchino, needed a convenient indicator of the molecular-repair activity of cells embedded in Siberian permafrost, where they obtained their samples. One such indicator is the rate at which certain building blocks of proteins undergo a normal molecular change. Because they're asymmetrical molecules, amino acids come in both right-handed and left-handed forms, labeled D and L respectively. Left alone at any temperature above absolute zero, any individual amino acid molecule occasionally will switch from the right-handed configuration to the left-handed one and vice versa in a process called racemization. A bowl of any given amino acid, regardless of its initial balance of left- and right-handed molecules, eventually will reach an equilibrium state, with roughly equal numbers molecules of each configuration at any moment. The speed of this process differs among the amino acids and depends on temperature and other parameters of the environment, McDonald says. "It could literally range from hours in boiling acidic water to billions of years in a cold dry sediment." This process, while normal to chemistry, is inimical to biology. Proteins in living organisms don't work if they contain right-handed amino acids. But the right-to-left and left-to-right reactions go on continuously even in living cells. As a result, McDonald explains, organisms have evolved "enzymes that basically go around and scavenge the D amino acids, the right-handed ones, and get rid of them. Because if the D amino acids build up to too high a level, they can poison protein synthesis and essentially kill the cell." These enzymes prove so efficient that a living cell maintains a near- zero ratio of right-handed to left-handed amino acids, or D/L ratio. This process provides a sort of clock to determine the age of dead cells or cells with suspended molecular activity. Once the repair process stops, the clock starts ticking, and the level of right- handed amino acids slowly rises. "If you know what the temperature of the environment is, and if you've measured the rate of racemization [molecular switching] at that temperature, you can then predict what the amount of racemization would be for a given age," McDonald says. Amino acids undergo this right-to-left-to-right switch at different rates, so McDonald chose to study the fastest amino acid, one called aspartic acid. To calibrate the clock, the team studied the rate at which aspartic acid switched from left to right at different temperatures and ran a carbon-14 dating technique on the samples. Organisms build all their carbon-containing molecules using carbon from the environment. That carbon is a mixture of stable and radioactive forms of carbon. The amount of carbon-14, a radioactive form, continuously decreases after a cell stops building new molecules with atmospheric carbon-when it's frozen or dies, for example. By measuring the total amount of carbon-14 in a sample, researchers have an independent way to determine the sample's age. The researchers can express the amino acid clock's results in a variety of ways. Because the process depends on temperature, McDonald compared the temperature predicted by the measured amount of right-handed amino acid in a sample with the actual average temperature of the permafrost at the depth of the sample. The amino acid clock suggested that the samples had been continuously cooled to a temperature of minus 19 degrees Celsius (minus 2 degrees Fahrenheit). But the measured temperature of the permafrost is 6 to 8 C (11 to 14 F) warmer. When the clock's results are expressed as a temperature, colder means less measured right-handed aspartic acid. What could account for the discrepancy? "If there's less of the right-handed form" than would be expected if no biological activity had been taking place, McDonald says, "then the only real explanation for that is that the organisms are scavenging these D amino acids and getting rid of them." Enzymes convert D amino acids to the L form or break down the D amino acids, recycling the parts of the molecule. McDonald and colleagues suggest two possible ways the soil organisms could have continued this molecular maintenance. First, the permafrost may have warmed periodically, thawing the frozen organisms. But independent research shows only very low levels of molecular activity in permafrost samples. The second possibility is that the organisms continue to scavenge right-handed aspartic acid even at permafrost temperatures. This process would be slow but steady. And if the organisms are performing maintenance on aspartic acid, McDonald argues, they may also be maintaining DNA and other essential biomolecules (although there is, as yet, no direct evidence of this). McDonald's results suggest that permafrost organisms can continue this molecular maintenance for at least 30,000 years. "We can't absolutely prove it, but the assumption is that there's essentially no cell division. So we're talking about a cell population that's basically been there since soon after permafrost was deposited," McDonald says. On to Mars "A lot of papers are being published in exobiology but very few have really direct relevance to the goals of exobiology," says E. Imre Friedmann, a microbial ecologist and astrobiologist at NASA Ames Research Center. "This is one of those which does have a direct relevance to the goals of exobiology. This is a possible method to document microbial activity in martian permafrost." While Mars experts have gathered evidence of ice on Mars for some time, results in May from the Odyssey spacecraft showed large amounts of subsurface ice. Friedmann says the amino acid clock could help determine if life once existed on Mars-or even if living organism still reside in the martian permafrost. "Now having said that, this is not something that we will do tomorrow. Because in order to use this method, we will have to go to Mars, drill into Mars to reach the permafrost and bring permafrost back. It is not something which will be done next year. But [the technique] is a very important preparation for a more advanced stage of exploration of Mars." Drilling would be an essential first step because the surface of Mars cannot sustain liquid water. "Conditions in considerable depth below the surface may be more suitable for life," Friedmann says, "but of course this is also uncertain. Friedmann calls martian permafrost the most likely place to find life on the red planet. But for life to have survived, even in almost suspended animation, organisms would have to have survived far longer on Mars than they have so far on Earth. "The oldest Siberian permafrost is about three million years old," Friedmann says. "On Mars, life, if there was any, probably stopped over three billion years ago. Billion. So it is an enormous difference between the Earth conditions and the martian conditions. Still it is not impossible that we can find living bacteria, not near the surface, but maybe quite deep." What's next? McDonald pictures uses for the amino acid clock on Earth and on Mars. Here at home, he plans to obtain samples from permafrost in Alaska and deeper in the Siberian subsurface. As for Mars, he says, "There are several instruments under development that would measure amino acid D/L ratios on Mars, from a lander or rover." And the Mars lander scheduled for 2009 may well have a drill capable of obtaining permafrost samples-if a lander can reach the parts of Mars suspected of having permafrost, not an easy feat. If such instruments work, they would save the considerable trouble of transporting samples of martian permafrost back to Earth. In the lab, McDonald hopes to examine the enzymes organisms use to maintain a viable amino-acid ratio. "I'm interested in how these organisms go back and forth, for instance, between the enzymes that require oxygen and other enzymes that don't in order to keep doing this repair," he says. "We don't really know what the enzymes involved are. It could be the same enzyme that they would use at the higher temperatures or they could have evolved a different enzyme or a different way of dealing with it. We don't really know that. That's one of the things we'd like to look at." Additional information on this article is available at http://www.astrobio.net/news/article253.html. _____________________________________________________________________ WOULD ET VOTE? THE LIKELIHOOD OF EXTRATERRESTRIAL DEMOCRACY By Douglas Vakoch From Space.com 15 August 2002 Although it's still two years until the next presidential election, we're already seeing signs of politicians positioning themselves for the Oval Office. If extraterrestrials some day pick up our radio and television broadcasts, hearing the latest news of political jockeying, will they be flabbergasted by our methods of choosing a leader? Would the idea of one vote per person seem hopelessly quaint to an advanced alien nation? Maybe not. If psychologist Albert Harrison is correct, ETs might feel very much at home with the notion of going to the ballot box. Or at least they would be familiar with the process of having input into the control of their lives, even if it doesn't take the form of presidential elections. According to Harrison, a Professor of Psychology at the University of California at Davis, if we detect a signal from advanced extraterrestrials, there's a good chance that the basic principles of democracy play a role in their society. Get the full story at http://www.space.com/searchforlife/seti_vote_020815.html. _____________________________________________________________________ SPACEWATCH DETECTION OF "LOST" CONTOUR SPACECRAFT From the Spacewatch web site http://spacewatch.lpl.arizona.edu/contour.html 16 August 2002 In this subtracted image in which moving objects are revealed by pairs of images, one dark and one bright, taken by Jim Scotti with the Spacewatch 1.8-meter telescope on Kitt Peak on 2002 August 16, there are two parallel trails near one of the predicted positions of the CONTOUR spacecraft, radio contact with which had been lost the day before following a commanded large velocity impulse maneuver. These trails were discovered and measured by Jeff Larsen during his re-examination of the data. The curvature of the trails is a natural characteristic of the drift scanning process at this high declination. The images are oriented with north at the right and west up. The positive images are the earlier time. The fact that there are two trails indicates that the spacecraft must have separated into two pieces that are still moving in nearly parallel directions. Please indicate (c)2002 The Spacewatch Project, Lunar and Planetary Laboratory, The University of Arizona in any reproductions of this image. [http://spacewatch.lpl.arizona.edu/Jeff/contour.jpg] Spacewatch Lunar and Planetary Laboratory University of Arizona Tucson, Arizona [See the CONTOUR Status Reports elsewhere in this issue for more information. -DJT] An additional article on this subject is available at http://www.spacedaily.com/news/contour-02h.html. _____________________________________________________________________ TUNGUSKA--MAKING AN IMPACT AT THE LONDON "CATASTROPHES" CONFERENCE Geological Society of London release 17 August 2002 The "Tunguska Event" refers to the tremendous explosion on the morning of June 30, 1908, that laid waste to about 2150 square kilometers of Siberia in the region to the north and northwest of Lake Baikal in Russia. The event is widely attributed to be the impact of a comet or asteroid. New research, however, is suggesting alternative homegrown geophysical mechanisms to explain the event. Andrei Ol'khovatov, an independent Russian researcher, will be convening a special workshop to air the competing sides of the growing "Tunguska debate." For Ol'khovatov, the Tunguska event has all the hallmarks of an extreme terrestrial geophysical event. He argues that it can be explained by the combined effects of known tectonic and meteorological activity--albeit combined at a much larger scale--and argues that there is good evidence that such a peculiar and rare combination of tectonic and meteorological activity was reported from the Siberian region at the time of the event. Wolfgang Kundt of the Institute for Astrophysics at the University of Bonn argues that the event was the result of the tectonic expulsion of some 10 megatons of natural gas. This natural gas, vented outwards at supersonic and subsonic speeds, was responsible for the peculiar meteorological activity across the region. Another researcher, Christoph Brenneisen, reports that soil samples collected by the second German-Russian Tunguska expedition in autumn 2000 from the epicenter of the disaster area showed clear enrichment of the disaster layer of 1908 with alkaline earth metals such as lanthanides and strontium. However, he argues that the source of these elements need not definitely have an extra-terrestrial, but might instead come from the Earth's mantle via deep-seated geologic- tectonic structures. Jesus Martinez-Frias of the Centro de Astrobiología (CSIC-INTA) in Madrid proposes an alternative impact origin for Tunguska, that it may be related the fall of anomalously large atmospheric ice blocks ("megacryometeors"). Such large ice blocks have been reported striking the Earth's surface at an increasing rate during the past few years. These unusual events of falls of large blocks of ice were first reported in Spain in 2000, but additional occurrences have been identified in many others parts of the world (e.g. Italy, Austria, Argentina, Colombia, Canada and The Netherlands). A research program was initiated in Spain to study the nature of the ice blocks, showing that they mostly share the characteristics of large atmospheric hailstones. Professor Martinez-Frias argues that while megacryometeors represent a much less violent threat than extraterrestrial impacts, they constitute a more immediate hazard. This release is one in a series of media advisories for the forthcoming conference Environmental Catastrophes & Recovery in the Holocene (28 August - 2 September, 2002) Brunel University, West London. For further information, contact the convener Dr. Iain Stewart. Please note that the Geological Society of London is only promoting the conference, and is not able to take media enquiries concerning it. Abstracts: http://atlas-conferences.com/cgi-bin/abstract/caiq-07 http://atlas-conferences.com/cgi-bin/abstract/caji-24 Contact: Dr. Iain Stewart Department of Geography & Earth Sciences Brunel University, Uxbridge UB8 3PH, UK Phone: +44 1895 203215 E-mail: iain.stewart@brunel.ac.uk _____________________________________________________________________ GREAT DEBATES PART VI: ENCORE PERFORMANCE From Astrobiology Magazine 19 August 2002 Last month for the Astrobiology Magazine, astrobiologists debated the "Rare Earth" hypothesis. The debate series, separated into five separate installments, ran on July 15, 17, 22, 24 and 29. As a follow-up, debate participants Christopher McKay and Michael Meyer answer questions submitted by our readers. Q: What might constitute a life form? I'm assuming complex life must be carbon and water-based, but could they be based on liquid carbon dioxide or liquid oxygen as a solvent, and even methane or ammonia? Christopher McKay: We have only one example of life: life on Earth, life as we know it. We can hardly guess at what other types are possible. Carbon chemistry and water solvent seem particularly well suited for life, and our current detection strategies are based on this model. Looking for carbon/water life means that we need to look for planets with Earth-like conditions in terms of the pressure, temperature range, and, most importantly, with liquid water present. Liquid carbon dioxide and ammonia are both good solvents and theoretically could be the liquid of life. However we do not know of any planets with large amounts of either of these as liquids. Q: In your opinion, what is the single strongest piece of evidence that we are alone; that the Earth is a biological anomaly among the billions of planetary experiments that must have failed? Michael Meyer: The strongest evidence is a lack thereof--we don't have evidence of life beyond Earth. However, from what we think we know (and this seems to be the opinion of the debaters) microscopic life may be common. But, if your question is about intelligent life, the unknowns are tremendous. Out of approximately 10,000,000,000,000,000,000,000 stars, it seems reasonable that at least one other star is capable of harboring a planet sustaining complex life. If complex life is rare, space is so vast and inimical to life that we may never learn about our nearest neighbor. But, if there are many planetary experiments that did not fail, then it is just a matter of time before we learn that we are not alone. Q: Did life appear multiple times independently on Earth during different climatic epochs? Christopher McKay: All life on Earth can be mapped into one tree or web of life. This argues for a single genome of life, a common ancestor. We have no evidence that directly suggests that life appeared multiple times on Earth. The isotopic shift of carbon-13 with respect to carbon-12 that appears throughout the geological record is consistent with the shift that is due to present types of life. This isotopic shift is found in sediments as old as 3.8 billion years, suggesting a continuity of life between then and now. Q: What credibility does the astrobiology community attach to the panspermia hypothesis? Is there any evidence one way or another? Christopher McKay: The question of panspermia is attracting new interest due to recent research on the possibility of interplanetary and interstellar transfer of life. There's evidence that some grains of material in our solar system came from beyond our solar system. Recent experiments show that microorganisms can survive dormancy for long periods of time and under space conditions. We also now know that rocks can travel from Mars to Earth. Finally, there's evidence that life appeared very early on the Earth--about 3.8 billion years ago. Q: How important is the moon in the evolution of life on this planet? I read somewhere that tidal forces, planetary rotation, etc., caused or moderated by moon's gravitation, were essential to the formation of life here. Michael Meyer: The moon could have played many roles, and the relative importance of those roles depends on how things got started on Earth. Early on, the moon was much closer, and so tides must have been spectacular. If life evolved in splash zones, with the necessary chemistry taking place during the wetting and drying of the tidal cycle, the moon would have been critical in turning the crank on this prebiotic chemical engine. Perhaps more critical, the moon has helped stabilized obliquity variations of Earth, such that we do not experience occasional major changes in our inclination. Right now, the Earth is tilted at 23.5 degrees, giving us seasons. Much higher variation in obliquity would generate greater extremes between summer and winter, and might be considered a major impediment to the evolution of complex life--but who knows? Tidal forces have moderated planetary rotation, but I don't think that's particularly important - other than a lengthening of the diurnal cycle. Interestingly enough, Mars is thought to tilt as much as 40 degrees every tens to hundreds of thousands of years. This occasional excursion into high obliquity may be the cause of many flow features we see on Mars today. A large martian moon would have moderated those obliquity excursions. Additional information on this article is available at http://www.astrobio.net/news/article254.html. _____________________________________________________________________ NEW ADDITIONS TO THE ASTROBIOLOGY INDEX By David J. Thomas http://www.lyon.edu/webdata/users/dthomas/astrobiology/astrobiology.h tml 19 August 2002 Astrobiology, exobiology and terraformation articles http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_article s1.html Astrobiology Magazine, 2002. Great debates VI: encore performance. Astrobiology Magazine. Terrestrial extreme environments articles http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_article s2.html S. Hart, 2002. Bacteria: survival in Siberia. Astrobiology Magazine. Human space exploration and microgravity effects articles http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_article s3.html Agence France-Presse, 2002. Manned China space mission "just around the corner". SpaceDaily. T. Phillips, 2002. In search of Moon trees. NASA Science News. Search for extraterrestrial intelligence (SETI) articles http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_article s4.html D. Vakoch, 2002. Would ET vote? The likelihood of extraterrestrial democracy. Space.com. Evolutionary biology and chemistry articles http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_article s5.html A. D. Anbar and A. H. Knoll, 2002. Proterozoic ocean chemistry and evolution: a bioinorganic bridge? Science, 297(5584):1137-1142. R. A. Kerr, 2002. Could poor nutrition have held life back? Science, 297(5584):1104-1105. _____________________________________________________________________ CASSINI WEEKLY SIGNIFICANT EVENTS NASA/JPL release 8-14 August 2002 The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Wednesday, August 14. The Cassini spacecraft is in an excellent state of health and is operating normally. See the "Present Position" web page at http://www.jpl.nasa.gov/cassini/english/where/. On-board activities this week included clearing of the ACS high water marks, a Radio Science Subsystem Ultra Stable Oscillator characterization and Periodic Instrument Maintenance, and a Radio and Plasma Wave Science High Frequency Receiver calibration. A quarterly status review was held for RADAR Analysis Software (RAS) development. A new development schedule shows significant changes to incremental and final delivery dates due to budget reductions. Additional refinements to the schedule are in work to assure that key tour capabilities of the RAS software are ready by the Delta Tour Readiness Review. Visual and Infrared Mapping Spectrometer flight software version 5.1 was delivered to the Project Software Library. A pre-check of the delivered Assisted Load Format file will be performed for validation followed by a Software Review Certification Requirement meeting at the end of August. System Engineering met with Instrument Operations (IO) personnel to review initial work on the IO level 4 Verification and Validation (V&V) plan. The plan looked good and will be issued as a template for other teams participating in V&V. Solar System Educator Institute Training took place this week. Thirty master teachers participated in workshops about various JPL missions, including a hands-on activity for Cassini involving topographical measurements and mapping. An overview of upcoming Cassini educational and public outreach activities was also presented. 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. _____________________________________________________________________ CONTOUR MISSION STATUS REPORTS NASA/JPL/JHUAPL releases Mission operations awaiting contact from CONTOUR spacecraft http://www.contour2002.org/news.php?id=17 15 August 2002, 9:15 AM EDT Mission operators are looking for a signal from CONTOUR, more than four hours after a scheduled maneuver to send the spacecraft from Earth's orbit onto a path to encounter multiple comets. CONTOUR's STAR 30 solid-propellant rocket motor was programmed to ignite at 4:49 AM EDT and deliver 1,920 meter-per-second boost, which CONTOUR needed to escape Earth's orbit. At about 140 miles (225 kilometers) above the Indian Ocean, the spacecraft was too low for NASA's Deep Space Network (DSN) antennas to track it at the scheduled time of the burn. The CONTOUR mission operations team at the Johns Hopkins University Applied Physics Laboratory expected to regain contact at approximately 5:35 AM EDT to confirm the burn, but by 9:00 AM EDT the DSN had not acquired a signal. The mission operations team is working through several backup plans to establish contact with the spacecraft, searching along the predicted trajectories for a successful burn. CONTOUR contact attempts continue http://www.contour2002.org/news.php?id=18 15 August 2002, 7:30 PM EDT Mission operators continue to scan the skies for the CONTOUR spacecraft, working through a list of strategies for re-establishing contact with the solar-powered probe through NASA's Deep Space Network (DSN). "We're still trying to get a telemetry link," says CONTOUR Mission Director Dr. Robert Farquhar, of the Johns Hopkins University Applied Physics Laboratory, Laurel, MD. "We're trying to send commands to spacecraft to switch between its two transmitters and use different on-board antennas, in case they turned off for some reason. But we really won't know what happened until we contact it." CONTOUR's STAR 30 solid-propellant rocket motor was programmed to ignite at 4:49 AM EDT and deliver a 1,920 meter-per-second boost that would send CONTOUR out of Earth's orbit and onto a path that would eventually take it past two comets. At about 140 miles (225 kilometers) above the Indian Ocean, the spacecraft was too low for DSN antennas to track it at the scheduled time of the burn. NASA's Jet Propulsion Laboratory, Pasadena, CA, operates the DSN. The CONTOUR mission operations team at the Johns Hopkins University Applied Physics Laboratory expected to regain contact at approximately 5:35 AM EDT to confirm the burn. When no signal was received, the team immediately began working through backup plans to re-establish contact, searching along the predicted trajectories for a successful burn. "We're looking at the nominal path, as if the burn occurred," Farquhar says. "We're working on the assumption that the motor fired, and the team is putting its priority there." CONTOUR's on-board computer is also carrying a command that, about 24 hours after the scheduled burn time, would turn the craft about 40 degrees and perhaps improve its antennas' fix on Earth. Farquhar adds that without knowing CONTOUR's status, it is difficult to know what commands it can, or did, execute. Still, he says, "we're cautiously optimistic that we will find the spacecraft." Mission operators continue to listen for a signal from CONTOUR http://www.contour2002.org/news.php?id=19 16 August 2002, 1:00 PM EDT Using its 34-meter antennas, NASA's Deep Space Network stations are scanning the spacecraft's expected path beyond Earth's orbit, attempting to pick up radio signals from CONTOUR's transmitters. The CONTOUR team is also awaiting feedback from several NASA-sponsored and other optical and radar sites that have been searching the skies for signs of the spacecraft. CONTOUR's STAR 30 solid-propellant rocket motor was programmed to ignite at 4:49 AM EDT on Aug 15, boosting the spacecraft out of an Earth parking orbit and onto a trajectory to encounter two comets over the next four years. The spacecraft was too low for DSN antennas to track it during the burn--about 140 miles (225 kilometers) above the Indian Ocean--and the CONTOUR mission operations team at the Johns Hopkins University Applied Physics Laboratory expected to regain contact about 45 minutes later to confirm the burn. No signal was received, and the team has been working through plans to find the craft along the predicted trajectories for a successful burn. CONTOUR's onboard computer was carrying a command that, starting at 6:00 AM EDT today, would have turned the spacecraft and pointed another of its four antennas toward Earth. So far, however, no signal has been received. Next operations: radar and radio checks http://www.contour2002.org/news.php?id=20 16 August 2002, 9:30 PM (EDT) Efforts to locate the CONTOUR spacecraft--through a series of telescope, radar and radio checks--are expected to continue through the weekend. On Monday, August 19, mission operators plan to check if CONTOUR automatically carries out a built in command to cycle through and transmit through all four of its antennas. The sequence is programmed to begin 96 hours after CONTOUR receives its last command--meaning it could start as early as 4:09 AM (EDT) or as late as 10:09 PM Monday--and would last several hours. "We aren't sure that the spacecraft is completely gone, and that's what we're going to be working on over the next several days," says Dr. Robert Farquhar, CONTOUR mission director from the Johns Hopkins University Applied Physics Laboratory, which built the CONTOUR spacecraft and manages the mission for NASA. CONTOUR, a Discovery-class mission to explore the nucleus of comets, was built and managed by the John Hopkins University Applied Physics Laboratory, Laurel, MD, for NASA. Additional information about CONTOUR is available on the Internet at http://www.contour2002.org. Additional articles on this subject are available at: http://www.space.com/missionlaunches/contour_search_020815.html http://spacedaily.com/news/020819013200.ibm8k6km.html http://spaceflightnow.com/news/n0208/15contour/ http://spaceflightnow.com/news/n0208/16contour/ http://story.news.yahoo.com/news?tmpl=story2&cid=624&ncid=624&e=1&u=/ ap/20020819/ap_on_sc/missing_spacecraft_4 _____________________________________________________________________ INTERNATIONAL SPACE STATION SCIENCE OPERATIONS STATUS REPORT NASA/MSFC release 02-202 14 August 2002 The Solidification Using Baffle in Sealed Ampoule (SUBSA) science team completed its fifth experiment run aboard the International Space Station last weekend. SUBSA is investigating manufacturing processes that could yield insights into semiconductor production on Earth. Impurities, or dopants, in semiconductors are used to control the opto-electronic properties of the semiconductor crystal, and the uniform distribution of the dopant is essential to achieve the desired properties. The goal of SUBSA is to study the resulting solids formed in microgravity where the motion of dopants caused by buoyancy forces are greatly reduced, resulting in more even distribution of the dopants. The test was the first to use an encapsulant in the sample tube. Liquid encapsulants are often used during semiconductor processing on Earth to form a thin film around the semiconductor as the semiconductor grows. This helps to prevent sticking between the sample and the container wall and results in fewer defects. Following the 15-hour run on Saturday, Flight Engineer Peggy Whitson on Sunday noticed a crack in the quartz sample tube as she prepared to remove the sample. The tube broke as she removed it. Whitson used tweezers and other tools to remove the remaining sample tube. A small quartz piece, from the sample tube floated away but was confined in the work area of the Microgravity Science Glovebox where SUBSA furnace is housed. The Glovebox, which features a sealed work area with windows and built-in gloves, is designed to contain experiments with fluids, flames, particles and fumes that could otherwise escape into the Station environment. Controllers and the science team are drafting plans to recover the particles and resume SUBSA operations. "We don't have a full answer yet for why this happened," said Dr. Aleksandar Ostrogorsky, SUBSA principal investigator with Rensselaer Polytechnic Institute, Troy, NY. During the past 2 years, we performed on ground 28 solidification experiments without the encapsulant and 2 experiments with the encapsulant, and this is the first ampoule that failed during processing. Based on the ground test statistics, the crack could be related to the encapsulant. The test itself was interesting and exciting because on video during the test we observed a relatively fast repositioning of the encapsulant and the melt. A dome-shaped free surface, which we've never seen on Earth, formed in the middle of the sample. We are studying the video and will be very interested to get this sample back for analysis." On Tuesday and Wednesday, members of the crew continued to record their experiences for the Crew Interactions experiment, which examines interpersonal factors that can affect operations on long space missions. On Wednesday, the crew removed depleted nutrient fluid from the Advanced Astroculture (ADVASC) experiment and refilled with fresh nutrients. ADVASC is growing soybean plants to learn whether they will produce seeds with improved oil, protein or carbohydrate content. This is the first soybean seed-to-seed experiment in space. Coming up for Commander Valery Korzun and Whitson on Saturday will be the Pulmonary Function in Flight Experiment (PuFF). The lung function test will study whether their Friday spacewalk had any affect on their health. Korzun and Whitson conducted the regular monthly PuFF test last Friday. The low-pressure environment of a spacesuit can cause nitrogen in the blood to form bubbles. Additionally, little is known about how the lungs can be affected by long-term exposure to microgravity. PuFF measures changes in the evenness of gas exchange in the lungs and changes in respiratory muscle strength. Scientists hope to find new ways to protect the health of space travelers in the years ahead, and to gain a better understanding of the effects of gravity on the lungs on Earth. Crew Earth Observations photography subjects this week included: fires in western Borneo, gold-mining cities near Johannesburg, South Africa, dry season fires in Angola, North African dust over the Mediterranean, islands and coastal features in the lower Amazon River basin, high central Andean Glaciers, and Lima, Peru. 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 Media Relations Department Phone: 256-544-0034 E-mail: Steve.Roy@msfc.nasa.gov _____________________________________________________________________ STARDUST STATUS REPORT NASA/JPL release 16 August 2002 There was one scheduled Deep Space Network tracking pass and all subsystems are normal. Stardust participated in the Solar System Educator Program training, designed to train pre-selected K-12 educators throughout the United States on many aspects of space exploration. As part of the educators' commitment, they agree to train an additional 100 educators within their region or district. The Education and Public Outreach team will provide the East Kentucky Science Center, Prestonsburg, Kentucky with a Stardust display highlighting aerogel. The museum is set to open in fall 2004 and will include a display about Stardust's encounter with Comet Wild 2. The Voice of America News reported on Stardust's interstellar dust collection on August 9th in a story entitled "Comet Chasers to Rely on Unique Synthetic Material." 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 9, Number 30.