MARSBUGS: The Electronic Astrobiology Newsletter Volume 6, Number 12, 11 May 1999. Editors: Dr. David Thomas, Department of Biological Sciences, University of Idaho, Moscow, ID, 83844-3051, USA. Marsbugs@aol.com or davidt@uidaho.edu. Dr. Julian Hiscox, Division of Molecular Biology, IAH Compton Laboratory, Berkshire, RG20 7NN, UK. Julian.Hiscox@bbsrc.ac.uk Marsbugs is published on a weekly to quarterly 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. Article contributions are welcome, and should be submitted to either of the two editors. Contributions should include a short biographical statement about the author(s) along with the author(s)' correspondence address. Subscribers are advised to make appropriate inquiries before joining societies, ordering goods etc. Back issues and Adobe Acrobat PDF files suitable for printing may be obtained via anonymous FTP at ftp.uidaho.edu/pub/mmbb/marsbugs or at the official Marsbugs web page at http://members.aol.com/marsbugs/marsbugs.html. The purpose of this newsletter is to provide a channel of information for scientists, educators and other persons interested in exobiology and related fields. This newsletter is not intended to replace peer-reviewed journals, but to supplement them. We, the editors, envision Marsbugs as a medium in which people can informally present ideas for investigation, questions about exobiology, and announcements of upcoming events. Astrobiology is still a relatively young field, and new ideas may come out of the most unexpected places. Subjects may include, but are not limited to: exobiology and astrobiology (life on other planets), the search for extraterrestrial intelligence (SETI), ecopoeisis and terraformation, Earth from space, planetary biology, primordial evolution, space physiology, biological life support systems, and human habitation of space and other planets. ------------------------------------------------------------------ CONTENTS 1) THE GREEN PARTY--POWERFUL PLANTS HAVE CHANGED THE WORLD By Leslie Mullen and David Noever 2) MARS SOCIETY TO LAUNCH ARCTIC RECONNAISSANCE From the Mars Society home page 3) CLOUDSAT TO REVOLUTIONIZE STUDY OF CLOUDS AND CLIMATE JPL release 4) NEW TOPEX/POSEIDON CD-ROM OFFERS MULTITUDE OF OCEAN VOYAGES JPL release 5) CASSINI MISSION STATUS REPORT JPL release 6) TODAY ON GALILEO JPL release 7) GALILEO PROVES OLD SPACECRAFT CAN LEARN NEW TRICKS JPL release 8) TURN LEFT AT CALLISTO--GALILEO HEADS FOR A DARING ENCOUNTER WITH IO'S VOLCANOES By Tony Phillips 9) GALILEO EDUCATORS' WORKSHOP--LIFE IN THE SOLAR SYSTEM JPL release 10) MARS GLOBAL SURVEYOR MISSION STATUS JPL release 11) MARS SURVEYOR '98 PARTICIPATING SCIENTIST PROGRAM AO OUT MAY 24 AO 99-OSS-02 ------------------------------------------------------------------ THE GREEN PARTY--POWERFUL PLANTS HAVE CHANGED THE WORLD By Leslie Mullen and David Noever From NASA Space Science News 10 May 1999 Biologists conducting Space Shuttle experiments may be one step closer to shedding light on the biggest power booster on the planet: a protein [complex] in green plants called Photosystem I. A German research team recently presented the results of their Space Shuttle experiment designed to crystallize Photosystem I molecules. According to the researchers, "This experiment has yielded the best data set thus far obtained from Photosystem I crystals." During photosynthesis, the cells in green plants undergo two simultaneous reactions, both of which rely on a separate kind of protein. Photosystem I protein molecules use the trapped energy in sunlight to convert carbon dioxide into carbon and oxygen. This provides the plant food in the form of carbohydrates, lipids, proteins and nucleic acids--the building blocks of life. Photosystem II protein molecules use light energy to split water into hydrogen and oxygen for plant respiration. [This is very oversimplified. DJT] Scientists crystallize protein molecules in order to study their complex internal structures. Because the molecules are too small to study directly under a microscope, scientists use X-ray diffraction to get a picture of the molecule. Shining X-rays through a crystal produces a scattering pattern, which is a type of blueprint. Think of a shadow cast through a picket fence--the shape of the shadow would tell you that the fundamental building block of the fence is a rectangular board. Shining X-rays through a protein crystal indicates the protein's shape, where it's located, and ultimately how it may work. High quality crystals--composed of ordered and repeating units of a particular protein--are required for X-ray diffraction. Some of the crystals grown in the microgravity conditions of space are more perfectly ordered than crystals grown on Earth. Microgravity can also affect the rate at which the proteins initiate new growth. Space crystals have shown a 10 to 20-fold larger volume compared to the Earth-grown counterparts. The Photosystem I protein [complex], sometimes called "the Earth's power station," was analyzed by a scientific team representing the Max Volmer Institute for Biophysical Chemistry and Biochemistry in Berlin, Germany. The team reported their results in their Final Report published from the Life and Microgravity Spacelab (LMS) mission. The team hopes these results will give scientists a more detailed knowledge of the Photosystem I molecule's shape, exact atomic positions, and biological functions. And by using the results of the experiments on the space shuttle, scientists can improve the crystallization conditions here on Earth. The Earth's environments--from forests to grasslands to the oceans--are direct products of the Photosystem protein molecules. From the beginning of life, Photosystem II processes in algae completely altered the atmosphere, transforming the carbon dioxide environment into an oxygen-rich one. The two Photosystem protein [complexes] underlie the Earth's balance between water and heat and between oxygen and carbon dioxide. They ultimately supply the nutrients for almost every living thing on the planet, as well. Most of the organisms on Earth receive their sustenance directly or indirectly from photosynthetic vegetation. Without the Photosystem[s], life as we know it would cease to exist. The space experiments were performed on ancient organisms called cyanobacteria, formerly known as blue-green algae or blue-green bacteria. As a family, these organisms form the fundamental basis of the entire marine food web and are often called "the grass of the sea." These early ancestors of modern plant cells (chloroplasts) were the first oxygenic organisms to convert light to energy on Earth. The cyanobacterium protein used in the space investigation, from the species Synechococcus elongatus, is found abundantly today. It represents more than half of the total biomass productivity in all open ocean environments and may process up to 50 percent of the excess carbon dioxide greenhouse gasses implicated in the current global warming debate. Burning carbon fuel such as oil and coal produces most of this excess carbon dioxide. This process currently supplies much of the world's power needs, but the fuel reserves are rapidly running out. Nonpolluting alternative fuel sources are being developed to take the place of oil and coal. In the 1970s, solar power--a clean and unlimited power source--seemed to be the most promising alternative. Harnessing the power of the Sun to power the Earth, however, has been plagued with difficulties. To generate a lot of power, you need extremely large solar panels. And what do you do for power when the sun sets? The Space Shuttle investigation is trying to discover what features of photosynthetic proteins allow for solar energy conversion. While humans have only been developing solar power technology for a few decades, plants have been evolving for billions of years to perfect their photosynthetic technique. By studying how plants accomplish this remarkable feat, scientists hope to someday also develop systems that use light as a power source. Identifying and studying characteristics of the protein's metabolism may someday also be used for applications in pollution prevention and environmental clean-ups. Knowing the Code Many essential biology questions depend on knowing the structure of proteins and enzymes. By charting their shapes, scientists can determine how the molecules work. But these molecules may also change shape when performing important functions, like carrying oxygen in blood hemoglobin. In photosynthesis, there are many energy producing conversion steps from sunlight to plant development and growth. Some estimates suggest that human biology depends on the action of nearly half a million different enzymes and proteins. But we only have a three-dimensional picture of shape and function for fewer than 1 in 100 of these complex chemicals. Since 1984, the Space Shuttle has carried experiments to determine the structures of large, biologically important molecules. This research has compiled results for a host of human diseases ranging from insulin for the control of diabetes, to the reverse transcriptase enzyme that, when blocked, inhibits HIV infection. Just as in human cells, the Photosystem proteins inside a plant cell are translated from amino acids. Amino acids have a 20- letter alphabet for each of the 20 naturally occurring amino acids (shown below as AAs). These amino acids are in turn translated from the complex array of nucleic acids in DNA (coded as the letters A, G, T and C). A description of the molecular code reads like an encrypted message: AAs =FFLLSSSSYY**CC*WLLLLPPPPHHQQRRRRIIIMTTTTNNKKSSRRVVVVAAAADDEEGGGG Starts = ---M---------------M------------MMMM---------------M----- ------- Base1 = TTTTTTTTTTTTTTTTCCCCCCCCCCCCCCCCAAAAAAAAAAAAAAAAGGGGGGGGGGG GGGGG Base2 = TTTTCCCCAAAAGGGGTTTTCCCCAAAAGGGGTTTTCCCCAAAAGGGGTTTTCCC CAAAAGGGG Base3 = TCAGTCAGTCAGTGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGTCAGT CAGTCAGTCAG... Much work remains to be done in uncovering the shape and detailed way the Photosystem power-converting molecules achieve their efficiency. By using the results from space shuttle experiments, someday we may understand how that transformation happens in detail. Such experiments make possible the study of proteins that had once proved too difficult to dissect at the molecular or atomic size. Life on the Edge Project A good illustration of how photosynthesis leads to environmental balance is the terrarium. A sealed jar of carefully balanced photosynthesizing organisms can sustain themselves for long periods without exposure to outside material nutrients or gases. Such a microbial terrarium can keep its ecological balance nearly indefinitely without any care or maintenance. The secret to this self-sufficiency is that green or purple photosynthesizing organisms generate their own source of life from the energy in light. This ability allows them to divide and multiply in a stable manner. NASA's "Life on the Edge" project tests some of the limits to this remarkable behavior. By closing several green biomass mixtures into sealed jars, these organisms are frozen within a deep freezer to a frigid -80 degrees C (-112 degrees F), temperatures exceeding the coldest winter weather in Antarctica (-44.5 degrees C, or -48 degrees F). Afterwards, the jars are thawed and opened, and scientists then grow the organisms in a culture to assess their viability. Healthy growing ecosystems have been revived from this ultimate deep freeze. [For more information on this story see http://science.nasa.gov/newhome/headlines/msad10may99_1.htm] ------------------------------------------------------------------ MARS SOCIETY TO LAUNCH ARCTIC RECONNAISSANCE From the Mars Society home page (http://www.marssociety.org) At a meeting of the Mars Society Steering Committee held at Stanford University March 12, it was decided that the Mars Society should implement a "reconnaissance in force" mission to Devon Island during the summer of 1999 to prepare for the deployment of the Society's planned Mars Arctic Research Station (MARS) during the summer of 2000. The reconnaissance mission, which will be undertaken on a cooperative basis with scientists from NASA Ames Research Center engaged in scientific study of the Devon Island Mars analog environment, will be led by the Society's Arctic Base Task Force leader Pascal Lee, and include Mars Society president Robert Zubrin, MARS lead architect Kurt Micheels, and other society personnel, including a correspondent who will provide regular expedition progress reports to the Society at large via the Internet. The expedition's primary purpose will be to choose the site for the MARS station. In addition, the mission will serve to provide project leaders with a direct sense of the problems to be addressed in deploying and operating the MARS in the Devon Island environment. Preliminary studies of methods of conducting human exploration on Mars will also be undertaken, including, possibly, a simulated Mars pressurized rover excursion utilizing a humvee vehicle whose loan has been tentatively pledged to the project by the U.S. military. Following the Steering Committee meeting, the Society's Arctic Base Task Force met for a full-day design review on March 13. A number of ideas were forwarded for reducing the cost of the base as well as increasing the fidelity of the cost estimates. As a result, various work packages were assigned to members of the Task Force, which collectively are expected to result in an improved design by June. Devon Island is a polar desert featuring a large meteorite impact crater that has created geology very similar to Mars. The purpose of the MARS base will be to support scientific study of the area; test a prototype flight-like Mars combination habitat/lab/workshop module in the field for operability and habitability; use the module as a test bed for NASA-, industry-, or university-developed life support or field exploration equipment; learn how to conduct human Mars exploration effectively, so as to maximize the cost/effectiveness of future human Mars expeditions; and to inspire the public with the vision of humans pioneering Mars. The MARS base is being developed on the basis of private funding raised by the Mars Society. Donations are tax deductible. A 24- page brochure describing the project at length has been completed and will be posted shortly on the Web site. The reconnaissance expedition will take place in July 1999. A full report on the expedition, as well as the rapidly developing plans for the MARS base itself, will be presented at the Mars Society Second International Convention, to be held in Boulder, Colorado, August 12-15, 1999. ------------------------------------------------------------------ CLOUDSAT TO REVOLUTIONIZE STUDY OF CLOUDS AND CLIMATE JPL release 3 May 1999 NASA will take a revolutionary, global look at clouds with a new spaceborne radar capable of peering deep into their interior to study their structure, composition and effects on climate. Cloudsat, which will fly in 2003, will use an advanced radar to "slice" through clouds to see their vertical structure, providing a completely new observational capability from space -- current weather satellites can only image the uppermost layers of clouds. Cloudsat will be the first satellite to study clouds on a global basis. "A trio of satellites will provide unprecedented information on how clouds help transfer solar energy to and from our planet's atmosphere," said Dr. Ghassem Asrar, associate administrator for Earth Sciences, NASA Headquarters, Washington, DC. "The data from Cloudsat will help us understand changes in the Earth's climate on global, regional and local scales. An important contribution of Cloudsat is the way it will fly in formation with the Earth Observing System-PM platform and the PICASSO-CENA satellites." PICASSO-CENA, a cooperative mission between NASA and France, will study the role of transparent, thin clouds and aerosols, small atmospheric particles, and their effect on solar-energy transfer. Cloudsat's cloud-profiling radar capability will allow scientists to study the three-dimensional structure of most clouds important to weather and climate. This capability complements an instrument aboard PICASSO-CENA, which will observe the vertical structure of thin clouds and aerosols. These two missions will provide critically needed satellite measurements that will help researchers understand how the Earth's solar energy and climate interact on a global scale. Cloudsat data also will complement the Earth Observing System-PM satellite, which will collect data on the dynamics of Earth's atmosphere, and the Triana mission, both to be launched in 2000. Dr. Graeme Stephens of Colorado State University, Ft. Collins, CO, will be principal investigator of the Cloudsat mission. NASA's Jet Propulsion Laboratory, Pasadena, CA, will manage the international mission, which will include participation from the United States, Canada, Germany and Japan. The estimated cost of the Cloudsat mission is $135 million. NASA's contribution will be approximately $111 million, with additional funding provided by the Canadian Space Agency, the U.S. Department of Energy and the U.S. Air Force. The Canadian Space Agency also is developing key radar components and contributing scientific expertise. Ball Aerospace & Technologies Corp., Boulder, CO, will build the Cloudsat spacecraft. The Cloudsat mission continues the strong commitment to Earth Systems Science undertaken by NASA's Office of Earth Science, which oversees a long-term, coordinated research enterprise designed to study the Earth as a global environmental system. The Jet Propulsion Laboratory is a division of the California Institute of Technology, Pasadena, CA. ------------------------------------------------------------------ NEW TOPEX/POSEIDON CD-ROM OFFERS MULTITUDE OF OCEAN VOYAGES JPL release 7 May 1999 Armchair adventurers and educators are invited to explore marine mammals in the Gulf of Mexico, investigate the El Niņo phenomenon, or simply discover "what's up" in the world of Earth-orbiting satellites through a new multimedia CD-ROM, "Visit to an Ocean Planet," produced by NASA and the French space agency. Ocean expeditions, interactive games, teacher resources and classroom activities are featured in an array of educational learning tools, quizzes and global snapshots of ocean circulation patterns based on data obtained by the TOPEX/Poseidon satellite, a joint mission between NASA and France's Centre National d'Etudes Spatiales (CNES). More than an hour of digital video, audio, images and text captions describes everything from the impetus for the mission to significant science results obtained during the satellite's three- year primary life span. "Students will be introduced to cutting- edge concepts in science, mathematics and engineering," said Susan Digby, educational outreach representative on the TOPEX/Poseidon mission at JPL. This educational tool provides background materials, movies, images and classroom activities on three main topics: climate, oceans and life. Targeted primarily for middle- school students, the material is tailored to meet criteria of the National Education Standards office, and offers learning modules on three main topics: climate, oceans and life. One section enables students to learn about the ocean via interactive games that allow them to plan excursions to the nutrient-rich Gulf of Mexico. This gulf region experiences cyclonic eddies, which attract pods of sperm whales and can produce a variety of severe weather patterns. Another section contains a self-guided multimedia tour of the 1997-1998 El Niņo, which was one of the most severe El Niņo conditions in recent history, and provides students interested in oceanography careers with a chance to follow the studies of a group of contemporary oceanographers. The CD-ROM also includes an easy-to-use Earth-orbiting satellite game, which illustrates how TOPEX/Poseidon, along with other satellites, operates from space. The CD-ROM can be ordered free of charge at http://topex- www.jpl.nasa.gov/education/education.html Launched in August 1992, the TOPEX/Poseidon mission was designed to provide information about the changing topography of the world's oceans which, in turn, helps scientists to understand the ocean's role in the global climate. The mission is managed by JPL for NASA's Office of Earth Science, Washington, DC. JPL is a division of the California Institute of Technology. ------------------------------------------------------------------ CASSINI MISSION STATUS REPORT JPL release 7 May 1999 On course for Saturn, the Cassini spacecraft remains in excellent health and targeted for the second of its two flybys of the planet Venus next month. On June 24, Cassini will fly about 600 kilometers (373 miles) from Venus, gaining a boost in speed from that planet's gravity. In August, Cassini flies past Earth at an altitude of 1,166 kilometers (725 miles), about five times higher than the Space Shuttle's orbit. The Earth swingby will bend Cassini's flight path toward Jupiter, where Cassini will perform yet another flyby at a distance of 9.7 million kilometers (6 million miles), using Jupiter's gravity to swing the spacecraft on to its final destination of Saturn. Cassini's cosmic dust analyzer is performing well and has returned some of the mission's first scientific measurements. It has been continuously measuring the dust environment in the inner solar system since March 25. It is expected that the measurements will continue for nearly another decade. During the initial 41-day period of measurements, the instrument has detected at least 7 dust impacts. The size and speed of the particles seems to be consistent with dust from both interplanetary and interstellar sources, but it is not possible to clearly identify the source for these individual particles. The measurements are consistent with previous observations done by similar instruments on NASA's Galileo and Ulysses spacecraft, which discovered the stream of interstellar dust particles that flows into the solar system. The Stardust spacecraft will fly through this stream and take samples for return to Earth along with comet dust samples. The Cassini flight team's schedule continues to be dominated by routine maintenance of the spacecraft systems, as well as development of software for both the spacecraft and ground systems. Communications with the spacecraft are conducted through the antennas of NASA's Deep Space Network. Cassini is traveling at about 107,725 kilometers per hour (66,940 miles per hour) and has traveled more than 1.346 billion kilometers (836,400,000 miles) since launch October 15, 1997. The Cassini/Huygens mission to Saturn and Titan, a joint project of NASA, the European Space Agency and the Italian Space Agency, is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA. JPL is a division of the California Institute of Technology. ------------------------------------------------------------------ TODAY ON GALILEO JPL release 4 May 1999 Once again, most of Galileo's attention is directed toward Jupiter as the spacecraft's Solid State Imaging camera and Utraviolet Spectrometer spend most of the day observing the giant planet. The activity is only briefly interrupted toward the end of the day to allow the Extreme Ultraviolet Spectrometer to perform a remote observation of the Io torus. On the flyby front, the spacecraft flies past Ganymede today at 3:18 am PDT [see note 1] at a distance of 636,000 kilometers (396,000 miles). Throughout the day, the spacecraft's camera takes images of a variety of cloud features in Jupiter's atmosphere. These observations are designed to determine the dynamics of cloud motion in three dimensions, with high spatial and time resolution. Each feature is observed three to six times as it moves across Jupiter's sunlit hemisphere. Some of the features are also imaged after they have rotated into the night side of Jupiter, to look for lightning flashes which the scientists hope to correlate with clouds seen in the daylight images taken earlier in the same areas. The features covered by this observation campaign are equatorial waves, high speed jets, clouds in the north and south equatorial belts, and white ovals. In addition, the camera also makes an observation of Jupiter's aurora to measure its vertical structure at high resolution. The Ultraviolet Spectrometer takes advantage of these observation opportunities to also make measurements of these features. In addition to the observations taken along with the spacecraft camera, the Ultraviolet Spectrometer also performs its own measurements of Jupiter. In one type of observation, the spectrometer measures hydrogen in Jupiter's dark atmosphere. Without sunlight, changes in hydrogen loss are caused by interaction with particles in Jupiter's magnetosphere and mixing of the upper atmosphere with lower cloud levels. In a second type of observation, taken on Jupiter's lit side, the spectrometer measures hydrocarbons in Jupiter's upper atmosphere. Finally, the spectrometer takes a look at aurora in Jupiter's atmosphere. These observations will allow scientists to further study the dynamics of Jupiter's upper atmosphere, and its interaction with Jupiter's magnetosphere. For more information on the Galileo spacecraft and its mission to Jupiter, please visit the Galileo home page at http://www.jpl.nasa.gov/galileo Note 1. All times listed correspond to the Pacific Time zone (currently daylight time) and spacecraft event time. Radio signals indicating that an event has occurred on the spacecraft reach the Earth 33 to 50 minutes later, depending on the time of year. Currently, Pacific Daylight Time (PDT) is 7 hours behind Greenwich Meridian Time (GMT), and it takes radio signals 49 minutes to travel between the spacecraft and Earth. ------------------------------------------------------------------ GALILEO PROVES OLD SPACECRAFT CAN LEARN NEW TRICKS JPL release 5 May 1999 NASA's Galileo spacecraft team members are all smiles after Galileo proved to be a star pupil by successfully demonstrating specially designed, newly installed software and saving this morning's flyby of Jupiter's pockmarked moon Callisto. During previous flybys of Jupiter's moons, a recurring electrical glitch caused the spacecraft computer to reset and enter "safing" mode, shutting down all non-essential functions until ground controllers could restore normal operations. The Galileo team pooled engineering and problem-solving talents to develop special software, known as a "bus reset patch." The name refers to Galileo's "data bus," which transfers information to various parts of the spacecraft. The software was designed to boost Galileo's I.Q. by teaching it to recognize symptoms of the glitch and correct the problem itself, without entering safing mode. The spacecraft was put to the test twice on Monday, May 3, when the glitch popped up as Galileo was approaching Callisto. Galileo quickly diagnosed the problem, determined there was no threat to spacecraft health, and decided for itself not to enter safing mode. This allowed all spacecraft and scientific functions to continue uninterrupted, with Galileo snapping pictures and gathering observations from an altitude as close as 1,322 kilometers (821 miles) above Callisto. "Galileo proved it's an 'A' student," said Project Manager Jim Erickson. "This is an example of our efforts at JPL to make the spacecraft more independent and better able to evaluate and deal with problems without intervention from ground controllers." "We're so thrilled that our efforts paid off and Galileo performed as we had hoped," said Nagin Cox, who helps oversee the team of current and former Galileo personnel that developed the new software patch. In an unrelated occurrence during this morning's Callisto flyby, the pointing control for the scan platform, which aims Galileo toward observation targets, switched on its own from a very accurate gyro-controlled system to a less accurate backup mode that uses the star scanner without gyros. Nonetheless, the spacecraft continued to record its observations, but observations taken by an instrument called the near infrared mapping spectrometer may be less sharp than planned. Preliminary analysis shows this anomaly occurred just after Galileo's closest approach to Callisto, or 7:56 a.m. Pacific Daylight Time, the time the signal was received on Earth. The Galileo team is investigating this anomaly, and preliminary analysis shows it may be related to previous gyro anomalies. Galileo has been orbiting Jupiter and its moons since December 1995. Its original, two-year mission ended in December 1997, and the spacecraft is currently more than halfway through a two-year extended tour, called Galileo Europa Mission. JPL manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is a division of the California Institute of Technology, Pasadena, CA. ------------------------------------------------------------------ TURN LEFT AT CALLISTO--GALILEO HEADS FOR A DARING ENCOUNTER WITH IO'S VOLCANOES By Tony Phillips From NASA Space Science News 5 May 1999 This morning at 6:56 AM Pacific Daylight Time, NASA's Galileo spacecraft zoomed past Jupiter's moon Callisto at a distance of only 1315 km--94 times closer than Voyager's closest approach in 1979. Early reports indicate that the encounter was a success and that Galileo is operating normally. The main purpose of today's flyby was to use the gravitational pull of Callisto to modify Galileo's orbit. After 14 months spent carefully studying Europa, Galileo is beginning a series of four encounters with Callisto spanning a six month period designed to bring the craft closer to Jupiter and Io. Scientists hope that a close-up view of Jupiter's atmosphere will reveal important new details of wind and storm patterns, including the billowing thunderstorms that grow to heights several times those on Earth. Water circulates vertically in Jupiter's top layers, leaving large areas drier than the Sahara desert, and others drenched like the tropics. Mapping the distribution of water and its role in Jupiter's weather might help scientists understand Earth's more fast-paced weather changes. While mission planners are eager for a closer view of the giant planet, what they really have their eye on is Io, the innermost of Jupiter's large satellites. Io is one of the most exotic places in the solar system. It is literally bursting with volcanoes that spew sulfurous plumes over 300 km high. One called Prometheus may have been active for at least 18 years! In October or November, after a series of four orbit-changing encounters with Callisto, Galileo is scheduled to make two daring close approaches to Io, possibly flying through a volcanic plume. Volcanic ejecta change the appearance of Io's surface on a daily basis and sulfurous material that escapes the moon form a gigantic torus of gas circling Jupiter. Nestled inside Jupiter's magnetosphere, the "Io torus" is enormous. With a diameter the size of Io's orbit it spans 844 thousand km and has an important impact on Jupiter's magnetic environment. As Io moves along its orbit and through this magnetized plasma torus, a huge electrical current flows between Io and Jupiter. Carrying about 2 trillion watts of power, it's the biggest DC electrical circuit in the solar system. The dozens of active volcanoes on Io result from 100-meter high tides raised in its otherwise solid surface by nearby Jupiter and the other Galilean satellites. Although this process is fairly well understood, much of Io's forbidding environment remains a mystery. Galileo's final two orbits will feature close flyovers from 611 kilometers, then 300, kilometers away. Suspense will be high as Galileo flies right over Pillan Patera's active plume of frozen sulfur. If all goes well, Galileo's instruments will capture breathtaking images with 6 meters resolution. "There is a good chance that Galileo will not survive either of the Io encounters because of the intense radiation exposure," explains Ron Baalke of the Jet Propulsion Laboratory. "In fact, ever since the primary mission at the end of 1997, the spacecraft has been operating at beyond its design in terms of accumulated radiation exposure." In the vicinity of Io the radiation environment is severe, strong enough to kill a human. Nevertheless, Galileo's mission may not end with the Io flybys. "If the spacecraft survives, there is a possibility of extending the mission beyond 1999," continued Baalke. "It would be an engineering mission where the spacecraft degradation due to radiation exposure is observed over time, and limited fields and particles data is collected. There will be no images returned in this 'extended' extended mission. Any Galileo mission beyond 1999 is still pending NASA approval and funding." Whatever the fate of Galileo, the Io flybys will be a hard act to follow. Portions of this story were taken from the Water, Fire and Ice web site maintained by JPL, and from the "Today on Galileo" series by Ed Hirst, a Galileo mission planner. [For more information on this story see http://science.nasa.gov/newhome/headlines/ast05may99_1.htm] ------------------------------------------------------------------ GALILEO EDUCATORS' WORKSHOP--LIFE IN THE SOLAR SYSTEM JPL release http://quest.arc.nasa.gov/ltc/special/galileo/ 7 May 1999 "Life in the Solar System" 14 May, 9:00 AM - 12:00 AM PST "Educators' Symposium" 14 May, 12:00 PM - 3:00 PM EST Arizona State University, NASA's Jet Propulsion Laboratory (JPL), and NASA's Ames Research Center cosponsor the Symposium designed for K-12 educators. Our understanding of the Universe and recent discoveries in the Solar System have focused research interests in the emerging field of Astrobiology. Astrobiology involves scientific disciplines that include biology, chemistry, geology, mathematics and physics. Scientists and engineers who are involved in Astrobiology-related research will develop concepts to include: * Life on Earth in extreme environments * The possibility of Life in the Solar System (past and present) * The conditions necessary for life to exist in the Universe * An overview of NASA's search for life in the Solar System * An introduction to the emerging interdisciplinary field of astrobiology and classroom applications and resources In advance of attending the event you will need to have Downloaded RealPlayer. Information on how to download the player is available on this web site: http://quest.arc.nasa.gov/ltc/special/galileo/ ------------------------------------------------------------------ MARS GLOBAL SURVEYOR MISSION STATUS JPL release 7 May 1999 NASA's Mars Global Surveyor spacecraft returned to normal mapping operations Wednesday night, May 5. The spacecraft is healthy and all of its science instruments are turned on. A gimbal, or hinge, on the spacecraft's dish- shaped high-gain antenna still has a restriction that limits its range of motion, but this will have no effect on the mission until next February when the Mars-to-Earth geometry will again prevent the antenna from pointing continuously at Earth. Engineers are looking at options for conducting the mission after February so that there will be a minimal impact on how much science data the mission can collect and send to Earth. At 7:45 AM Pacific Time today, Global Surveyor fired its small thrusters for about two minutes in order to fine-tune its orbit around Mars. The mapping orbit was designed so that the spacecraft does not fly over precisely the same swath of Martian landscape, or "ground track," from one week to the next. The spacecraft must fire its thrusters every few months to keep the necessary ground-track separation. This is especially important now since the science team is in the process of an intensive four- week campaign to acquire stereo images of the planet. ------------------------------------------------------------------ MARS SURVEYOR '98 PARTICIPATING SCIENTIST PROGRAM AO OUT MAY 24 AO 99-OSS-02 4 May 1999 Release Date: May 24, 1999 Proposals Due: August 24, 1999 The National Aeronautics and Space Administration (NASA) is releasing a NASA Announcement of Opportunity (AO 99-OSS-02) entitled Mars Surveyor '98 Mission Participating Scientist Program. This opportunity solicits proposals for Participating Scientists on the Mars Surveyor '98 mission whose expertise is sought for reducing and validating scientific data from the mission; preparing raw and reduced data for archiving in NASA's Planetary Data System; and analyzing, interpreting, and publishing scientific results, as well as operational components associated with the collection of data required for the proposed scientific investigation. Participation is open to all categories of organizations, foreign and domestic, including educational institutions, profit and nonprofit organizations, NASA Centers, and other Government agencies. Upon the release date specific guidance for proposal preparation will be available electronically from the World Wide Web by selecting "Research Opportunities" at http://spacescience.nasa.gov/research.htm. Printed copies may be requested by E-mail to debra.tripp@hq.nasa.gov or by writing to NASA Participating Scientist Program, Jorge Scientific Corporation, Suite 700, 400 Virginia Avenue, SW, Washington, DC 20024; TEL: (202) 554-2775. Further information regarding specific program elements may be obtained from Mr. Joseph M. Boyce, Research Program Management Division, Code SR, Office of Space Science, NASA Headquarters, Washington, DC 20546-0001; TEL: (202) 358-0302; E-mail: (jboyce@hq.nasa.gov). ------------------------------------------------------------------ End Marsbugs Vol. 6, No. 12