MARSBUGS: The Electronic Astrobiology Newsletter Volume 8, Number 20, 28 May 2001. Editors: Dr. David J. Thomas, Science Division, Lyon College, Batesville, AR 72503-2317, USA. dthomas@lyon.edu Dr. Julian A. Hiscox, 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 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 from the official Marsbugs web page at http://welcome.to/marsbugs. 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 from 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, the biology of terrestrial extreme environments, planetary biology, primordial evolution, space physiology, biological life support systems, and human habitation of space and other planets. _____________________________________________________________________ CONTENTS 1) STUDY OFFERS INSIGHTS INTO EVOLUTIONARY ORIGINS OF LIFE; ARTIFICIAL ENZYME ABLE TO SYNTHESIZE RNA From SpaceDaily 2) COMPLEX LIFE CONDITIONS AROSE EARLIER ON EARTH From Space.com 3) MENAGERIE OF MARS SCOUTS: BOLD NEW PROPOSALS FOR EXPLORING THE RED PLANET By Leonard David 4) THE MASS EXTINCTION THAT LEFT THE DINOSAURS STANDING From the NASA Astrobiology Institute 5) GALILEO GETS ONE LAST CLOSE ENCOUNTER WITH JUPITER'S CALLISTO NASA release 01-97 6) MICROORGANISMS SURVIVE ONE STEP CLOSER TO MARS ENVIRONMENT: GROWTH OF METHANOGENS ON A MARS SOIL SIMULANT WITHOUT THE STANDARD BUFFER University of Arkansas at Fayetteville release 7) NASA GIVES GREEN LIGHT FOR DEEP IMPACT MISSION DEVELOPMENT NASA release 01-99 8) NEW DUST DEVILS, DUNES & MORE FROM MARS GLOBAL SURVEYOR JPL image advisory 9) GALILEO SUCCEEDS IN ITS CLOSEST FLYBY OF A JOVIAN MOON JPL release 10) NEW ADDITIONS TO THE ASTROBIOLOGY INDEX By David J. Thomas 11) GALILEO MILLENNIUM MISSION STATUS JPL releases 12) TODAY ON GALILEO JPL releases 13) ISS STATUS REPORT NASA/JSC release 14) MARS ODYSSEY MISSION STATUS JPL release 15) STARDUST STATUS REPORT JPL release _____________________________________________________________________ STUDY OFFERS INSIGHTS INTO EVOLUTIONARY ORIGINS OF LIFE; ARTIFICIAL ENZYME ABLE TO SYNTHESIZE RNA From SpaceDaily 17 May 2001 In some of the strongest evidence yet to support the RNA world--an era in early evolution when life forms depended on RNA--scientists at the Whitehead Institute for Biomedical Research have created an RNA catalyst, or a ribozyme, that possesses some of the key properties needed to sustain life in such a world. The new ribozyme, generated by David Bartel and his colleagues at the Whitehead, can carry out a remarkably complicated and challenging reaction, especially given that it was not isolated from nature but created from scratch in the laboratory. This ribozyme can use information from a template RNA to make a third, new RNA. It can do so with more than 95 percent accuracy, and most importantly, the length or the exact sequence of letters in the original template does not restrict its ability. The ribozyme can extend an RNA strand, adding up to 14 nucleotides, or letters, to make up more than a complete turn of an RNA helix. Get the full story at http://www.spacedaily.com/news/life-01n.html. _____________________________________________________________________ COMPLEX LIFE CONDITIONS AROSE EARLIER ON EARTH From Space.com 21 May 2001 Earth's massive land slabs were on the move much earlier in the planet's history than previously assumed, a research team says, and that means complex life had enough heat and food to evolve then too. It has been widely held that plate tectonics, or the motion of Earth's plates and continents, dates back 1.9 billion years, but geologist Timothy Kusky at St. Louis University worked with a team of scientists that found data showing the plates began moving much sooner... ..."This discovery shows that the plate tectonic forces that create oceanic crust on Earth today were in operation more than 2.5 billion years ago," Kusky said in a prepared statement. That would date them back to Earth's earliest geologic time period--the Archean. Get the full story at http://www.space.com/scienceastronomy/planetearth/earth_moving_010521 .html. _____________________________________________________________________ MENAGERIE OF MARS SCOUTS: BOLD NEW PROPOSALS FOR EXPLORING THE RED PLANET By Leonard David From Space.com 21 May 2001 Mars attracts! Everything from a solar-powered hopper and high- flying vehicles to a Mother Goose craft that unleashes tiny robotic goslings--these are among the candidates ready to serve as a new breed of future Mars explorer. Dozens of Red Planet exploration schemes are on the table this week, all under NASA review as proposals for the space agency’s Mars Scout program. A little aerial "dogfight" might even be on tap between supporters of sensor-carrying aircraft zipping across Martian skies and advocates of instrumented balloons breezing about the planet. Get the full story at http://www.space.com/missionlaunches/missions/mars_scout_program_0105 21-1.html. _____________________________________________________________________ THE MASS EXTINCTION THAT LEFT THE DINOSAURS STANDING From the NASA Astrobiology Institute 22 May 2001 A mass extinction about 200 million years ago, which destroyed at least half of the species on Earth, happened very quickly and is demonstrated in the fossil record by the collapse of one-celled organisms called protists, according to new research led by a University of Washington paleontologist. "Something suddenly killed off more than 50 percent of all species on Earth, and that led to the age of dinosaurs," said Peter Ward, a UW Earth and space sciences professor. Evidence indicates the massive die-off was linked with an abrupt drop in productivity, the rate at which inorganic carbon is turned into organic carbon through processes such as photosynthesis. The waning productivity coincided with a sharp decline in radiolaria (included among protists), which was the focus of the new research. One example of productivity, Ward explained, occurs in the spring when fertilizer washes into waterways and triggers large algae blooms. The processes at work in that scenario were reversed 200 million years ago, he said. There is no definitive evidence yet on what caused the demise of so many species, Ward said. However, the suddenness of the event is similar to two better-known mass extinctions--one 250 million years ago at the end of the Permian period that killed some 90 percent of all species, the other 65 million years ago at the end of the Cretaceous period that sent the dinosaurs into oblivion. The extinction 200 million years ago, at the boundary between the Triassic and Jurassic periods, killed the last of the mammal-like reptiles that once roamed the Earth and left mainly dinosaurs, Ward said. That extinction happened in less than 10,000 years, in the blink of an eye, geologically speaking. Ward is the lead author on a paper detailing the evidence, published in the May 11 edition of the journal Science. Others participating in the research are James Haggart and Howard Tipper of the Geological Survey of Canada in Vancouver, British Columbia; Elizabeth Carter, a researcher at Oregon's Portland State University; David Wilbur, a UW oceanography research scientist; and Tom Evans, a UW junior in chemistry and Earth and space sciences. The evidence from the extinction was gathered at two sites in the Queen Charlotte Islands, off Canada's British Columbia coast. "These sites are among the most remote places in the world," Ward said. "There are no roads anywhere close by. The forests are virgin old growth, and the wave action is such that you can't get there by boat." Samples from a spot called Kennecott Point, in the northern Queen Charlottes, and from Kunga Island, about 100 miles to the southeast, showed a sharp decline in the presence of organic carbon, even at places where levels of inorganic carbon rose. The organic carbon decline correlated with the decline of radiolarians, one-celled organisms that serve as a food source for a number of marine species. "These provide the best record of how nasty the extinction was at this boundary," Ward said. The mass extinction 200 million years ago occurred just before the breakup of Pangea, which contained all the land on Earth in one supercontinent. At the time, the Queen Charlotte Islands--which now lie between 52 and 54 degrees north latitude--were probably on the equator or in the southern hemisphere, Ward said. "These are tropical fossils. There are many kinds of fossils in these rocks," he said. And they tell a story of a calamity that came on with stunning swiftness. "This is the first time ever that we can see how sudden this event was," he said. "It was very quick, not a long protracted episode." What's next Ward now has done research on the last three of the Earth's mass extinctions (scientists know of five) and has found that each happened quite quickly. Bolstered by a recent astrobiology grant from the National Aeronautics and Space Administration, he plans to lead researchers back to the Queen Charlottes this summer to look for more clues in the Triassic-Jurassic extinction, including potential causes. More information on this article is available at http://nai.arc.nasa.gov/index.cfm?page=dinosaur_standing. _____________________________________________________________________ GALILEO GETS ONE LAST CLOSE ENCOUNTER WITH JUPITER'S CALLISTO NASA release 01-97 22 May 2001 On a third and final tour of duty in the Jovian system, NASA's dauntless Galileo spacecraft makes its closest pass yet to Jupiter's outermost large moon. Friday, May 25, the orbiter should skim over Callisto, at an altitude of about 123 kilometers, or 76 miles, at 7:24 AM EDT. If Callisto were the size of a baseball, that would be just a nickel's thickness away. Mission managers expect the pull of the moon's gravity to alter Galileo's orbit around Jupiter. "The main reason we're flying so close to Callisto is to set up flybys of Io," said Dr. Eilene Theilig, Galileo project manager at NASA's Jet Propulsion Laboratory (JPL), Pasadena, CA. Io is an intensely volcanic moon closer to Jupiter that continually resurfaces itself with fiery eruptions. Galileo will pass over polar regions of Io in August and October to help scientists determine if the seething and violent moon generates its own magnetic field. "Since we have to go close to Callisto anyway to get to Io, we'll take advantage of the opportunity for studying Callisto," said JPL's Dr. Torrence Johnson, Galileo project scientist. Unlike the planet's other large moons, Callisto, which is about as big as the planet Mercury, appears to be inactive and still bears craters billions of years old. Although earlier magnetic studies by Galileo indicated that Callisto may have a liquid saltwater layer deep beneath its surface, Callisto hasn't drawn the excitement generated by Io or its sister moon Europa, which appears to have liquid water closer to its surface, or two-toned Ganymede. "Callisto is sort of the ugly duckling of the moons, but it's the one we need to look at to get the bombardment history of the Jovian system," Johnson added. "The craters on Callisto are the visible record of what sizes of comets and other objects have pelted Jupiter and its moons with what frequency over the past four billion years." Data from the flyby will be transmitted to Earth over the next two months. Scheduled observations include high-resolution imaging to study the density of small craters and the details of how some features appear to be degraded or eroded, said Dr. Duane Bindschadler, leader of Galileo's science planning team. "Some earlier imaging of Callisto has shown fewer small craters than expected." Scientists also plan to snap new pictures of Io, though from a much greater distance than Callisto, and hope to see if a volcanic plume detected near Io's North Pole five months ago is still active. On August 5, Galileo will pass directly over the plume's source area at an altitude of less than 350 kilometers, or about 220 miles. Another set of planned observations this week will point at Jupiter. Galileo will make a map of Jupiter's clouds in infrared wavelengths. "One goal is to see if fresh clouds are still being made at the same types of locations they were during similar mapping more than five years ago," said Dr. Kevin Baines, JPL atmospheric scientist. Another is to check for "brown barges," a type of dark cloud that was prominent on Jupiter when NASA's two Voyager spacecraft flew by in 1979, but has not been seen during the years since Galileo began orbiting Jupiter in 1995. Baines believes recent observations from Earth-based telescopes hint at a return of brown barges. Galileo's mission was originally scheduled to end in 1997, but has been extended repeatedly as the spacecraft continues to return scientific discoveries. The orbiter has survived more than three times the cumulative radiation exposure it was designed to withstand. Some electronic components have been affected by the radiation, and each swing near Jupiter increases the odds of more serious damage from exposure to the radiation belts around the planet. Galileo has made 30 previous flybys of Jupiter's large moons, including seven of Callisto. Before reaching Jupiter, it made close passes of Venus, Earth and two asteroids. After three more encounters with Io and one with the small inner moon Amalthea, Galileo's mission will end in 2003 with a final plunge into the crushing pressure of Jupiter's atmosphere. JPL, a division of the California Institute of Technology in Pasadena, manages Galileo for NASA's Office of Space Science, Washington, DC. Additional information about the Galileo, Jupiter and Jupiter's moons is available online at http://galileo.jpl.nasa.gov. Contacts: Donald Savage Headquarters, Washington, DC Phone: 202-358-1547 Guy Webster Jet Propulsion Laboratory, Pasadena, CA Phone: 818-354-6278 _____________________________________________________________________ MICROORGANISMS SURVIVE ONE STEP CLOSER TO MARS ENVIRONMENT: GROWTH OF METHANOGENS ON A MARS SOIL SIMULANT WITHOUT THE STANDARD BUFFER University of Arkansas at Fayetteville release 24 May 2001 University of Arkansas researchers have moved one step closer to growing microorganisms under Mars-like conditions by suspending them in water containing dissolved matter from Mars soil simulant. D. Ryan Ormond, Curtis R. Bekkum and Timothy Kral, associate professor of biological sciences, report their findings at 10:30 AM Wednesday, May 23, at the American Society for Microbiology meeting in Orlando. "We've eliminated one factor," said Kral, bringing them one step closer to approaching conditions on Mars. The researchers work with methanogens, microorganisms of the group Archaea. These organisms grow under anaerobic conditions, often in extreme environments, so Kral believes they may provide clues to the type of life that might be found below the surface of Mars. Methanogens can be found deep in the ocean, in the earth's crust or even in a cow's stomach, all of which are environments that might be considered harsh like the conditions found on Mars. Two years ago, Kral became the first scientist to grow microbes under some of the conditions found on Mars. Now he and research assistants Bekkum and Ormond have refined their experiments to eliminate one factor likely not found on Mars--a standard buffer used to keep the methanogens in suspension so they don't disintegrate. The researchers added Mars soil simulant in varying amounts to de- ionized water, then mixed it overnight. They decanted the mixture the next day and used the liquid fraction to wash and suspend the methanogens. The suspensions were added to Mars soil simulant in sealed anaerobic tubes and incubated, then analyzed for methane metabolism, an indicator of methanogen growth. The samples were compared to a control that was suspended in a standard sodium hydroxide buffer with bubbled carbon dioxide gas. "We can use the liquid fraction of water mixed with soil simulant to suspend the cells, and the organisms will grow," Kral said. The methanogens grew in the liquid fraction composed of water and simulant, although not as well as they did in the standard buffer. The researchers hypothesize that the pH, which was lower for the liquid fractions, may have reduced growth. Contacts: Tim Kral, associate professor, biological sciences Phone: 501-575-6338 E-mail: tkral@uark.edu Melissa Blouin, science and research communications manager Phone: 501-575-5555 E-mail: blouin@uark.edu _____________________________________________________________________ NASA GIVES GREEN LIGHT FOR DEEP IMPACT MISSION DEVELOPMENT NASA release 01-99 24 May 2001 NASA approved development of a robotic spacecraft mission that reads more like a story line from a science fiction movie script. Imagine intercepting a comet in deep space and using a heavy projectile to blow a hole in the celestial body, some seven stories deep and about the size of a football field. In a space exploration first, NASA's Deep Impact Mission will attempt to use a probe to collide with a comet in an attempt to peer beneath its surface. Scheduled for launch in January 2004, the unique spacecraft is expected to arrive at comet Tempel 1 in July 2005. Researchers hope the impact will allow them to measure freshly exposed material and study samples hidden deep below the surface of the comet, which could yield dramatic scientific breakthroughs. The 770 pound impactor, equipped with a camera, will separate from the flyby spacecraft and slam into the comet at an approximate speed of 22,300 miles per hour, blasting material from the comet into space with the force of its impact. A camera and infrared spectrometer on the flyby spacecraft, along with ground-based observatories, will study the resulting icy debris and exposed pristine interior material. The total cost of Deep Impact to NASA is $279 million. The principal investigator, Dr. Michael A'Hearn, University of Maryland, College Park, will lead a team consisting of NASA's Jet Propulsion Laboratory in Pasadena, CA, and Ball Aerospace Technology Corp., Boulder, CO, which will build the spacecraft. Comet Tempel 1 was discovered in 1867. Orbiting the sun every five and a half years, it has made many passages through the inner solar system. This makes it a good target to study evolutionary change in the mantle, or upper crust, of the comet. Scientists are eager to learn whether comets exhaust their supply of gas and ice to space or seal it into their interiors. They would also like to learn how a comet's interior is different from its surface. The controlled cratering experiment of this mission could provide those answers. NASA's Discovery Program emphasizes lower-cost, highly focused scientific missions within the Space Science enterprise. NASA has developed six other Discovery Program missions. Three have completed their missions, one is operational and two others, in addition to Deep Impact, are under development: * In 1997, the Mars Pathfinder lander, carrying a small robotic rover named Sojourner, landed successfully on Mars and returned hundreds of images and thousands of measurements of the Martian environment. * The Near Earth Asteroid Rendezvous (NEAR) spacecraft orbited the asteroid Eros for a year, ending with a successful landing on February 12, 2001. * The Lunar Prospector orbiter mapped the Moon's composition and gravity field and completed its highly successful mission in July 1999. * The Stardust mission to gather samples of comet dust and return them to Earth was launched in February 1999, and is on its way to comet Wild-2. * The Genesis mission to gather samples of the solar wind and return them to Earth is scheduled for launch on July 30, 2001. * The Comet Nucleus Tour (CONTOUR) mission to fly closely by three comets is scheduled for launch in June 2002. More information on the Deep Impact mission, including images and animations of the impact, is available on the Internet at: http://deepimpact.jpl.nasa.gov/ http://deepimpact.umd.edu/ Contact: Donald Savage Headquarters, Washington, DC Phone: 202-358-1547 An additional article on this subject is available at http://www.spacedaily.com/news/deepimpact-comet-01a.html. _____________________________________________________________________ NEW DUST DEVILS, DUNES & MORE FROM MARS GLOBAL SURVEYOR JPL image advisory 24 May 2001 Pictures of intriguing Martian features such as dust storms, dust devils, 3-D sand dunes, a recent image of "the face," and dark streaks that may be caused by dust avalanches have been released by the imaging team for NASA's Mars Global Surveyor spacecraft that have been taken during the extended mission phase that began February 1, 2001. The newly released images are products of the main objectives for the camera team during the extended mission, including: * Continued daily monitoring of Martian weather, storms, and polar cap changes; * Looking for changes caused by frost, wind, slope movements, and gully action with the high-resolution camera; * The opportunity to take a second look at features previously seen by the camera by turning and pointing the spacecraft to provide "3-D" (stereoscopic) views of certain areas; * Collecting pictures of other geologic features of interest, including sites being considered for the two 2003 Mars Exploration Rover landings. The images are available at these sites: http://www.msss.com/mars_images/moc/extended_may2001/ http://photojournal.jpl.nasa.gov http://mars.jpl.nasa.gov/mgs Mars Global Surveyor is managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, Washington, DC. JPL is a division of the California Institute of Technology in Pasadena. The Mars Orbiter Camera is operated by Malin Space Science Systems, San Diego, CA. Additional articles on this subject are available at: http://www.spacedaily.com/news/010525104821.bn6teg09.html http://science.nasa.gov/headlines/y2001/ast24may_1.htm?list52260 _____________________________________________________________________ GALILEO SUCCEEDS IN ITS CLOSEST FLYBY OF A JOVIAN MOON JPL release 25 May 2001 NASA's Galileo spacecraft has successfully completed a flyby of Jupiter's moon Callisto, closer than any of the spacecraft's 30 previous flybys of Jovian moons. Galileo's camera appeared to be working well from the time it was given a command Thursday afternoon to turn off then back on, right through and after the spacecraft's closest approach to Callisto at 4:24 AM (PDT) today, said Dr. Eilene Theilig, Galileo project manager at NASA's Jet Propulsion Laboratory, Pasadena, CA. Earlier, the camera appeared to be malfunctioning and probably did not capture some intended images taken of the moon Io from greater distance. Other instruments appear to have worked well throughout the encounter, Theilig said. "This incredible spacecraft has come through for us again," she said. Galileo passed about 138 kilometers (86 miles) above the surface of Callisto. The spacecraft has been orbiting Jupiter since 1995. Its closest previous encounter came within about 198 kilometers (123 miles) of the volcanic moon Io in February 2000. Today's pass was designed to use Callisto's gravity to alter the shape of Galileo's orbit so that the spacecraft will fly near Io in early August. As a bonus, the flyby gave scientists an opportunity to point their instruments for a close look at Callisto, a heavily cratered moon about the size of the planet Mercury. "It appears Galileo is on track for a polar pass by Io in August," Theilig said. "Because this spacecraft has already outlived expectations, the flight team prepared for contingency situations, but is always relieved to get through without encountering significant problems." If all goes well, images and other data will be transmitted to Earth by Galileo over the next two months, with an interruption of three weeks in June when Jupiter and Galileo will be behind the Sun from Earth's point of view. Intense radiation near Jupiter poses a risk to the spacecraft's electronics. Galileo's closest approach to Jupiter on this orbit was at a distance of about 460,000 kilometers (about 285,000 miles) from the giant planet's cloud tops on May 23. It will pass about 20 percent closer than that to Jupiter the same hour it flies by Io in early August. Galileo, built at JPL, has already received more than three times the cumulative radiation exposure it was designed to withstand and has continued making valuable scientific observations more than three years after its original two-year mission in orbit around Jupiter. The spacecraft's nuclear electrical power source--two radioisotope thermoelectric generators--continues to provide power to Galileo's instruments, computers, radio and other systems. The radio signals indicating today's Callisto flyby had taken place traveled for about 50 minutes at the speed of light and reached a large dish antenna at the Madrid station of NASA's Deep Space Network at about 5:15 AM PDT. The network relayed the signals to mission controllers at JPL. As of 11:00 AM today, the spacecraft had recorded about 90 percent of the scientific data that its instruments had been programmed to collect during this swing through the inner portion of the Jovian system. During the weekend, Galileo is scheduled to make additional observations of Callisto and of Jupiter's clouds. Magnetometer readings by Galileo during earlier flybys of Callisto indicated that this moon may have a layer of melted, salty water deep beneath its surface. However, unlike its sister moon Europa, which is likely to have liquid water much nearer its surface, Callisto shows a heavily cratered surface bearing the record of impacts by comets and other objects over billions of years. High-resolution images can help scientists understand the bombardment history of the Jovian system. Additional information about the Galileo mission is available at http://galileo.jpl.nasa.gov. Galileo was launched from NASA's Space Shuttle Atlantis on October 18, 1989. It began orbiting Jupiter on December 7, 1995. JPL, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, DC. Contact: Guy Webster Phone: 818-354-6278 _____________________________________________________________________ NEW ADDITIONS TO THE ASTROBIOLOGY INDEX By David J. Thomas http://www.lyon.edu/webdata/users/dthomas/astrobiology/astrobiology.h tml 28 May 2001 Articles about astrobiology, exobiology and terraformation http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_article s1.html K. Cowing, 1997. Astrobiology, formulating the big picture. HMS Beagle. T. Phillips, 2001. Unmasking the face on Mars. NASA Science News. J. Withgott, 2000. A Beagle sniffs for life on Mars. HMS Beagle. Articles about evolutionary biology and chemistry http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_article s5.html W. K. Johnston, P. J. Unrau, M. S. Lawrence, M. E. Glasner and D. P. Bartel, 2001. RNA-catalyzed RNA polymerization: accurate and general RNA-templated primer extension. Science, 292(5520):1319-1325. J. T. T. Mäkinen, J.-L. Bertaux, M. R. Combi and E. Quémerais, 2001. Water production of comet C/1999 S4 (LINEAR) observed with the SWAN instrument. Science, 292(5520):1326-1329. M. J. Mumma, N. Dello Russo, M. A. DiSanti, K. Magee-Sauer, R. E. Novak, S. Brittain, T. Rettig, I. S. McLean, D. C. Reuter, and Li-H. Xu, 2001. Organic composition of C/1999 S4 (LINEAR): a comet formed near Jupiter? Science, 292(5520): 1334-1339. Space.com, 2001. Complex life conditions arose earlier on Earth. Space.com. SpaceDaily, 2001. Study offers insights into evolutionary origins of life; artificial enzyme able to synthesize RNA. SpaceDaily. _____________________________________________________________________ GALILEO MILLENNIUM MISSION STATUS JPL releases 23 May 2001 NASA's Galileo spacecraft today passed the closest point to Jupiter of the spacecraft's current orbit of the giant planet, and remains healthy as it heads for a flyby of Callisto, the outermost of Jupiter's four largest moons. Galileo swung within about 460,000 kilometers (about 285,000 miles) of Jupiter's cloud tops at 10:33 AM PDT time, according to engineers managing the spacecraft from NASA's Jet Propulsion Laboratory, Pasadena, CA. Flying that close to Jupiter exposes the spacecraft's electronics to potential harm from intense radiation belts. "We have indications Galileo is bearing up well to the harsh environment, but it is still in a challenging environment," said Dr. Eilene Theilig, Galileo project manager at JPL. "As anticipated, we are seeing an intermittent anomalous behavior in the camera, similar to what we saw during Galileo's last encounter five months ago. Prior to high-priority observations, we plan to cycle power to the instrument off and on to decrease the risk of losing images. Cycling the power has cleared the intermittent anomaly in the past." Galileo is on course to pass within about 123 kilometers (76 miles) of Callisto at 4:24 AM PDT on Friday. Galileo has succeeded at more flybys of assorted worlds--including Venus, Earth, and two asteroids as well as Jupiter's four largest moons--than any other spacecraft, and Friday's will be its closest yet. As of 2:00 PM PDT today, Galileo had recorded about 30 percent of the scientific data that its instruments had been programmed to collect during this swing through the inner portion of the Jupiter system. The images and other data will be transmitted back to Earth over the next two months, with an interruption of three weeks in June when Jupiter and Galileo will be behind the Sun from Earth's perspective. The scheduled observations so far have included studies of Jupiter's clouds in infrared wavelengths, to improve understanding of the structure and dynamics of the planet's atmosphere and distant observations of Io, innermost of Jupiter's large moons, to monitor its volcanic activity. High-resolution images of Callisto's surface are planned for studies of how loose debris on the surface may be obscuring some of the smaller craters. Callisto is about the size of Mercury, with a heavily cratered surface that reveals billions of years worth of information about the size and frequency of comets and other objects hitting Jupiter and its moons. Galileo has already received more than three times the cumulative radiation exposure it was designed to withstand and has continued making valuable scientific observations more than three years after its original two-year mission in orbit around Jupiter. Its nuclear electrical power source--two radioisotope thermoelectric generators-- continues to provide power to the instruments, computers, radio and other systems on the spacecraft. 24 May 2001 The camera on NASA's Galileo spacecraft may not be working properly as the spacecraft heads toward Jupiter's moon Callisto for a close flyby on Friday at 4:24 AM (PDT). "We are not totally surprised, because we knew all along that Galileo might encounter difficulties from passing close to Jupiter's powerful radiation belts," said Dr. Eilene Theilig, Galileo project manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We are attempting to get a better understanding of the problem and to do what we can to minimize the loss of images." Voltage readings received from the camera yesterday and today are the same as when the camera was in a problem state during its last previous flyby, passing the moon Ganymede five months ago. During that flyby the condition was intermittent. It self-corrected spontaneously several times and was also corrected by commands from the ground to cycle its power off and on. More than half of the 120 images taken during that encounter period were captured successfully. This week, however, indications of the problem began shortly before this orbit's closest approach to Jupiter on Wednesday morning and have persisted in every voltage reading received since then, even after the power-cycle commands, Theilig said mid-day Thursday. "We may have lost the camera images scheduled so far, but the bulk of the camera observations are tomorrow morning at Callisto," she said. Other scientific experiments on Galileo, including infrared imaging of Jupiter's clouds and a radio study of Jupiter's atmosphere, have functioned properly during this pass through the inner portion of Jupiter's system. Data will be transmitted to Earth during the next two months. This is Galileo's 30th orbit of Jupiter since arriving at the giant planet in 1995. The original mission lasted two years in orbit, but the mission has been extended three times. By repeatedly passing through the highly radioactive environment close to Jupiter, Galileo has endured more than three times as much radiation as it was designed to withstand. Radiation damage to an electronic component is the main suspect in the camera's problem. Additional information about the Galileo mission is available at http://galileo.jpl.nasa.gov. Galileo was launched in 1989 and has been orbiting Jupiter since 1995. JPL, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, DC. _____________________________________________________________________ TODAY ON GALILEO JPL releases 21 May 2001 Today is the final full day of the cruise portion of Galileo's orbit of Jupiter before the onset of activities, which cover the 30th full orbit of the giant planet and its satellite moons, including a close flyby of Callisto next Friday. The final preparations are underway to make sure the spacecraft is ready for the next week of concentrated observations. Today the playback process is stopped. This process has been reading data off of the on-board tape recorder for the past 5 months. These data were stored during the last flyby of the satellite Ganymede during December of 2000 and during a calibration period on April 22 and 23 of this year. Routine maintenance of the tape recorder begins. This activity is designed to prevent the tape from sticking, and in this case, to get it ready for a full load of new data, which will be recorded over the six days. 22 May 2001 Today the final commands in the cruise portion of the orbit are completed. The routine maintenance of the on-board tape recorder is finished, and the spacecraft is turned approximately 5 degrees so that the Star Scanner, which helps determine which direction the spacecraft is pointed, can view the star Achernar (Alpha Eridani - the brightest star in the constellation of Eridanus, the River). This is the sixth brightest star in the star catalog that we maintain for the spacecraft. Such a bright star is used when the spacecraft is within about 15 Jupiter radii (1 million kilometers or 700,000 miles) of the giant planet because the intense radiation near Jupiter creates noise in the Star Scanner, and a strong star signal is needed in order to be seen through this noise. At 10:50 AM PDT [see Note 1] the sequence of commands that directs the spacecraft's activities for this encounter begins to execute. First up, at 6:20 PM PDT Galileo turns off telemetry to Earth in preparation for a Jupiter occultation, which occurs when the spacecraft passes behind Jupiter as seen from Earth. The Radio Science Team uses these opportunities to study the structure of the atmosphere of the planet by measuring changes in the radio signal as it passes lower and lower through the increasingly dense layers of the atmosphere. Telemetry is turned off to provide the maximum amount of power to the pure tone of the transmitted signal carrier frequency. The telemetry data collected by the spacecraft sensors during this time are stored in a buffer area of computer memory for later retrieval. At 8:20 PM PDT even the carrier tone is expected to be lost and the spacecraft will be completely hidden behind Jupiter's vast bulk. This continues until 10:48 PM PDT when the spacecraft will reappear on the other side of the planet. At approximately the same time, another type of occultation occurs: a solar occultation. This is when the spacecraft passes into the shadow cast by Jupiter. No specific observations are planned to mark this event, but the craft will be out of the warming rays of the Sun between 9:21 PM and 11:46 PM PDT. The on-board software that checks for health and safety of various spacecraft systems has been warned of the occultation and will not trigger any of its programmed responses during Galileo's passage through Jupiter's shadow. 23 May 2001 Today begins with an ending. The Radio Science Jupiter-Earth Occultation experiment, which began yesterday at 6:20 PM PDT, concludes at 12:50 PM PDT (yawn). [See Note 1] At this time the spacecraft resumes sending telemetry bits. Although Galileo itself is about 10.5 Jupiter radii from the planet (750,000 kilometers or 466,000 miles), the radio signal sent from the craft clears the top of the visible atmosphere by only 25,000 kilometers (15,500 miles) on its way to Earth, and the last of the effects that the atmosphere has on the signal should have dissipated. Just before 6:00 AM PDT, the Fields and Particles instruments [the Energetic Particle Detector (EPD), Magnetometer (MAG), Dust Detector (DDS), Heavy Ion Counter (HIC), Plasma Wave instrument (PWS), and Plasma instrument (PLS)] complete their configuration for the upcoming close pass by Jupiter. Now these instruments begin an 18- hour period of continuous data collection surrounding perijove, the closest point to Jupiter. These data will give information about the current state and variability of the Io Torus. The ionized gases that make up the Torus originate with the volcanic activity on Io, and form a doughnut-shaped ring that encircles Jupiter and extends from Io's orbit outward. At 6:00 AM PDT the Photopolarimeter Radiometer (PPR) instrument is turned on to be ready to observe the planet and its satellites. The two other optical instruments, the Solid State Imaging camera (SSI) and the Near Infrared Mapping Spectrometer (NIMS) are already on and ready. Their first opportunity is at 7:00 AM PDT, when Io passes into Jupiter's shadow. All three instruments observe the satellite as it passes into darkness, studying how the surface cools, and looking for hot spots. Three and a half hours later, after Io has left the shadow, PPR, NIMS and SSI take another look. PPR checks to see how the surface is warming up in the sunlight, NIMS does a global observation to monitor volcanic activity, and SSI takes some color pictures of the leading hemisphere of the satellite to help in the planning of observations in upcoming orbits when Io is the prime target of interest. All four of the large Galilean satellites (Io, Europa, Ganymede, and Callisto) are tidally locked to Jupiter, as the Earth's Moon is to Earth, and always show the same face to their parent planet. This means that one side of the globe is always in the lead as the body orbits, hence the name "leading hemisphere". Closest approach to Io comes at 11:08 AM PDT, at a distance of 341,771 kilometers (212,412 miles), a far cry from the 198 kilometer (123 mile) distance of the 27th orbit in February 2000. Shortly afterwards, at 11:24 AM PDT, Galileo reaches perijove, the closest point to Jupiter, at a distance of 6.3 Jupiter radii (450,400 kilometers, or 279,865 miles) above the cloud tops. Here the spacecraft is also relatively close to the small inner satellite Amalthea, and we take this opportunity to take several pictures of this body. These pictures will help the Navigation Team refine our knowledge of the orbit of the satellite. The long-term plan for the Galileo spacecraft includes a much closer flyby of that tiny body in November 2002. In the afternoon, a lighter schedule of activities includes PPR looking at a white oval storm in the atmosphere of Jupiter. This white oval is what remains from the merger of three smaller ovals during the past two years. This measurement will provide temperatures of the feature at unprecedented spatial resolution, and will help define models for convection and energy transfer in the atmosphere. Closest approach to the icy satellite Europa is at 5:41 PM PDT, at a distance of 781,513 kilometers (485,707 miles). NIMS takes this opportunity to perform an observation of the body to complete the global mapping that began in Galileo's Prime Mission. The day's activities wrap up in the evening with more NIMS observations of the Jupiter atmosphere. At 7:00 PM PDT, NIMS looks at cloud structures called "brown barges" in the northern hemisphere of the planet. These measurements provide information about the composition of the clouds, and how they change over time. At 8:00 PM and 9:00 PM the instrument also looks at a region of hot spots just north of the equator, again studying the composition and dynamics of the clouds. The day concludes at 10:00 PM PDT with SSI once again taking color pictures of Io to look for changes in the surface of the satellite. Io is the most volcanically active body in the solar system, and significant changes in its colorful surface have been noticed even in the geological blink of an eye represented by Galileo's Tour of the Jovian system. A busy day, with much more yet to come! 24 May 2001 Today has an action-packed morning and a laid-back afternoon. There is one close encounter of the satellite kind today, which is with Ganymede, the largest of Jupiter's moons, at 5:10 AM PDT [see Note 1]. Though the distance from Galileo to Ganymede is a seemingly remote 358,700 kilometers (222,930 miles), this is slightly less than the distance from Earth to our Moon, and still close enough to command the attention of several of the science instruments. The Photopolarimeter Radiometer instrument (PPR) leads the way with a global scale temperature map of the night side of Ganymede. Such observations show how the surface materials heat and cool when compared with other observations taken when the surface is in sunlight. This gives scientists information about the structure of those materials--how dusty or rocky, fluffy or solid, rough or smooth. This observation uses the radiometer, the portion of the instrument that measures temperatures. The polarimeter portion of PPR comes into play in four observations of Ganymede taken through PPR's polarizing filters. These observations occur throughout the day and catch the satellite under different lighting conditions. By measuring how much light is scattered off of the surface materials at different angles, scientists gain additional insight into the fine structure of those materials. About an hour after the Ganymede closest approach, the Solid State Imaging camera (SSI) looks back at the morning terminator, or day- night boundary of the satellite. Even at this distance, it still takes two pictures laid side by side to capture the entire lit hemisphere of the body. Pictures taken when the sun is low on the local horizon are useful for revealing the topography of a region. This will allow scientists to perform global-scale mapping of the grooves and furrows along the terminator. Also, fortuitously placed in the field of view are two prominent bright-ray craters and a crater chain, which were discovered earlier in the mission by Galileo imaging. Sharing observing time with these Ganymede studies, the Near Infrared Mapping Spectrometer instrument (NIMS) concentrates on viewing Jupiter itself. First up is a look at the white oval storm that PPR measured yesterday. Where PPR measured the temperatures, NIMS will be looking at the compositional variations in the clouds that make up the storm. The various Galileo instruments have been studying this feature and its precursors for the past four years, following the evolution of these long-lived and dynamic tempests. One of the questions that these measurements may help to answer is how these storms can survive for so long. The Great Red Spot, a giant high- pressure storm in the southern hemisphere of the planet, has survived in much the same form for over 330 years. An area just downwind of the Great Red Spot is also the target of two NIMS observations today. This region in the wake of this most well known of Jupiter's storms has been shown to be quite turbulent and variable, and these NIMS measurements will provide data on the composition and dynamics of the clouds. Also under NIMS scrutiny today are two areas in the northern hemisphere that are populated by storms called 'brown barges'. These relatively long-lived features, which appear only in the North Equatorial Belt on the planet, were first seen in pictures taken by the two Voyager spacecraft when they flew by Jupiter in 1979. They have been studied from Earth since 1997 and seem to be rich in methane gas, but whether they are clouds of methane, or holes in the clouds through which deeper concentrations of the gas can be seen is still a mystery. Never tiring of the details of Jupiter's atmosphere, NIMS also views a band of hot spots in the northern hemisphere. These spots have been popular targets for all of the optical instruments on Galileo over the course of the mission. By noon PDT, the spacecraft has receded far enough from Jupiter, at least 15 Jupiter radii or 1 million kilometers (660,000 miles) that radiation levels have dropped considerably. Radiation-related interference in the Star Scanner has decreased to the point that fainter stars can again be detected reliably, and the software begins to use three stars to calculate the orientation of the spacecraft. Since the encounter sequence began on Tuesday, the spacecraft had been relying on a single bright star to provide this information. The use of three stars provides a more accurate calculation over long periods of time. NIMS occupies Galileo's time in the afternoon by making a global observation of Jupiter. This is the first of three limb-to-limb, pole-to-pole maps by NIMS to look for compositional variation in the atmosphere over an entire Jovian rotation of just under 10 hours. Finally, at 10:00 PM PDT, the second period of continuous data collection begins for the six Fields and Particles instruments. These instruments are the Energetic Particle Detector (EPD), Heavy Ion Counter (HIC), Magnetometer (MAG), Dust Detector (DDS), Plasma instrument (PLS), and Plasma Wave Subsystem (PWS). This period will cover the closest approach to the primary target for this orbit, the satellite Callisto, which is coming up tomorrow. 25 May 2001 Today's activities include the main focus of attention for this orbit, the close flyby of Jupiter's moon Callisto. This occurs at 5:14 AM PDT [see Note 1] at a distance of only 123 kilometers (76 miles) above the icy surface. At that time, Galileo is flying at a speed of 9.7 kilometers per second (6.0 miles per second or 21,700 miles per hour) relative to that satellite. Coincidentally, this flyby occurs on the fortieth anniversary of President John F. Kennedy's famous speech to the U.S. Congress, on May 25, 1961, in which he committed the nation to a manned moon landing by the end of the decade. At that time, the U.S. had only launched one spacecraft that had successfully escaped Earth orbit and fulfilled its mission-- the Pioneer 4 Lunar flyby in March of 1959. The U.S. and NASA were still over a year away from launching our first successful planetary mission, the Mariner 2 flyby of Venus. See how far we've come! In contrast, the Galileo spacecraft had five successful planetary encounters (one of Venus, two of Earth, and two of asteroids) even before reaching its primary goal of Jupiter! But now the spacecraft is approaching Callisto's night side. This makes it difficult to observe Callisto, because to do so would also mean looking very near the Sun, which is hazardous to our remote sensing instruments. So we take this opportunity to continue our observations of Jupiter itself. The Near Infrared Mapping Spectrometer (NIMS) performs the last two of its three limb-to-limb, pole-to-pole global maps of the disk of Jupiter, looking for compositional variation in the atmosphere of the planet. The science instruments then shift their attention to Callisto. Shortly after 3:00 AM PDT [see Note 1], Radio Science configures the spacecraft for an occultation. On Tuesday night, the body that came between Earth and Galileo was Jupiter. This time, Callisto itself blocks our communications with Galileo for about an hour. The radio signal to Earth is changed to a pure tone, with no telemetry modulation, and the science team will be looking for the effects on the radio signal of the extremely tenuous charged-particle atmosphere of the satellite. They will be measuring the vertical distribution of free electrons above the surface. While no telemetry is being sent to the ground, engineering and science measurements will be stored both in on-board computer memory, and on the tape recorder. In particular, the Fields and Particles instruments [Energetic Particle Detector (EPD), Heavy Ion Counter (HIC), Magnetometer (MAG), Plasma instrument (PLS), and Plasma Wave Subsystem (PWS)] will be recording continuous high-rate, high-time-resolution data for about an hour centered on the closest approach. This recording will assist with studies of the Callisto's induced magnetic field and its interaction with the Jovian magnetosphere. The measurements from the various instruments will contribute to an understanding of particle pickup processes near Callisto, and thermal and non-thermal plasma interactions in the region. About 45 minutes before closest approach, the Photopolarimeter Radiometer instrument (PPR) performs a brief calibration of its signal before embarking on a high-resolution scan from east to west across the night side of Callisto. This observation begins 14 minutes before closest approach and its purpose is to see how quickly different types of terrain cool off at night. A scant three minutes before closest approach, the spacecraft once again appears from behind the satellite as seen from Earth. This will be the first signal we will have heard in an hour, but it will only be the pure tone of the Radio Science occultation experiment as it probes the tenuous atmosphere from the ground up. The first telemetry is still an hour away! Just at closest approach, the Solid State Imaging camera (SSI) snaps the highest resolution near-terminator images ever taken of any icy satellite! From this vantage point, we may be able to see some boulders on the surface, and will be able to see small impact craters as well. Travelling at over 21,000 miles per hour at the time, the pictures would definitely be smeared by the motion while the shutter is open. However, the spacecraft employs a technique of moving the camera in the opposite direction of the spacecraft motion to try and keep the desired surface features steady. Shortly after this, SSI takes the first of two sets of pictures of a domed crater. Eighteen minutes later, another set is taken from a different angle. This will allow scientists to reconstruct a stereo view of the surface, and to accurately measure the heights of the features they see. NIMS next undertakes a high-resolution observation of a multi-ringed impact structure called Asgard, to study the composition of the surface materials. This is followed by a similar observation of a region near the crater Bran. SSI also views Bran crater with moderate resolution, to provide context for closer images taken during the 20th flyby in the Galileo series. Context observations are important because they allow for more precise location of high- resolution images and also reveal the kinds of terrain and the geologic features (such as large impact craters) that may have influenced the area seen at high resolution. SSI takes several opportunities as the spacecraft recedes from Callisto to look back and collect such context images. SSI also takes pictures of an area called the Valhalla Antipode. Valhalla is a gigantic, continent-sized impact structure on Callisto, and the antipode is that area of the satellite that is exactly on the opposite side of the body. It is thought that the tremendous seismic energy generated by the impact would be focused on the point on the surface diametrically opposed, and may disrupt the surface in unusual ways. These images will determine if there is any 'weird terrain' caused by this seismic disruption at this location. PPR performs two scans from east to west across the satellite to measure temperatures and determine how the surface materials warm up during the course of a Callisto day (one Callisto day lasts for over 16 Earth days). The final science observation of the day, at 8:30 AM PDT, is a PPR scan from pole to pole, to determine the temperatures at the poles. These areas are likely to be the coldest places on Callisto, and may therefore be a place where exotic volatile materials might collect, similar to the way ice may collect at the poles of Earth's Moon and Mercury. Though this may seem like at least a full day's effort, the entire block of Callisto observations described here take place over a scant four hours--five and a half hours, if you include Radio Science! On the engineering side of the house, this evening sees a standard test of the spacecraft gyroscopes, in preparation for an Orbit Trim Maneuver, which will be executed next Wednesday. 26-27 May 2001 These last two days of the present encounter sequence are relatively quiet. The spacecraft is now receding from the planet and its satellites at a goodly clip, the tape recorder is nearly full of data, and it's nearly time to start playing that recorded data back. Saturday morning, at 2:30 AM PDT [see Note 1], the Solid State Imaging camera (SSI) takes its last look at Callisto. This parting shot is a color image of the fully lit disk of the satellite, and the first full-disk color look at this hemisphere of the body. At 9:00 AM PDT, the command sequence that will govern the activities of the spacecraft for the next ten weeks is transmitted from the tracking station at Goldstone in the Southern California desert. The antenna from which the commands are transmitted is 70 meters in diameter (230 feet). If this dish were on the surface of Callisto, Galileo, at its closest point during this flyby, could easily see it as an object 14 pixels across! On Sunday, just before 1:00 AM PDT, SSI begins a short series of observations of Jupiter. These pictures target some of the hot spots in the atmosphere, which have been popular objects of study by several of the science instruments during Galileo's tour of the Jovian system. These observations finish loading up the tape recorder, and shortly after SSI concludes its activities, the playback of the taped data begins. At the end of day Sunday, the Extreme Ultraviolet Spectrometer (EUV) instrument is turned on to prepare for its observing opportunities. This instrument cannot operate effectively close to Jupiter in the more intense radiation environment. It also shares some of the spacecraft data processing resources with the Heavy Ion Counter (HIC) instrument, so only one of the two instruments can be used at a time. We hope you have enjoyed following Galileo's journey through the Jupiter system this week. Our next close flyby is on August 5, when we will be sailing within 200 kilometers (124 miles) of the volcanic satellite Io. For more information on the Galileo spacecraft and its mission to Jupiter, please visit the Galileo home page at one of the following URL's: http://galileo.jpl.nasa.gov http://www.jpl.nasa.gov/galileo Note 1. Pacific Daylight Time (PDT) is 7 hours behind Greenwich Mean Time (GMT). The time when an event occurs at the spacecraft is known as Spacecraft Event Time (SCET). The time at which radio signals reach Earth indicating that an event has occurred is known as Earth Received Time (ERT). Currently, it takes Galileo's radio signals 50 minutes to travel between the spacecraft and Earth. ____________________________________________________________________________________ ISS STATUS REPORT NASA/JSC release 22 May 2001 Following two days of free flight since its launch Sunday, a unmanned Russian Progress spacecraft automatically docked to the back end of the International Space Station's Zvezda module at 7:24 PM Central time today. It is the fourth Progress dedicated to the resupply of the orbiting outpost. The Progress is carrying 3,100 pounds of supplies, including food, spare computer parts, and other logistical items which Expedition Two Commander Yury Usachev and Flight Engineers Jim Voss and Susan Helms will begin to unload on Wednesday. The Progress joins a Russian Soyuz craft that is linked to the earthward facing docking port of the Zarya module of the ISS, and paves the way for the arrival in three weeks of the Shuttle Atlantis with a five-person crew on the STS-104 mission to install the huge Joint Airlock to complete the second phase of the assembly of the station. While awaiting the arrival of the Progress, Voss and Helms spent Monday operating the Canadian-built station robotic arm to gather additional data as to the cause of the intermittent problem seen during last week's checkout activities in the backup, or redundant string of arm software. The test yesterday repeated some of last week's tasks and the redundant system worked perfectly. While the arm work was underway, Usachev tested the automatic and manual docking systems on the station in preparation for the Progress vehicle's arrival. The stage now is set for a complete "dry run" Thursday of the robotic arm movements required for installation of the Airlock. The station's robotic arm is the only means for attaching the Airlock on the Unity module since the shuttle's robot arm cannot reach the installation location. In preparation for that task, Thursday's checkout will mirror the movements planned in June as if the Airlock were attached to the arm. This test not only will validate the arm's operational capability, but also will be conducted on the redundant string of software and hardware. The primary string was tested nearly two weeks ago with no problems. If this week's checkout is successful, Friday's meeting of the ISS Mission Management Team will reassess the need for replacement of one of the arm's computer units, which is mounted on the arm itself. If required, the change out of the Computer Unit would be added to a previously scheduled "internal" spacewalk June 8 to reposition a docking cone in the cylindrical transfer compartment of the Zvezda module, which is linked to the Zarya module. That docking cone will serve as the target and initial contact point for the Russian Docking Compartment set to arrive at the station in late August or early September. While on-orbit activities continue, Space Shuttle Atlantis is being readied for launch shortly after 3:00 PM Central time on June 14. The orbiter will be moved to its launch pad at the Kennedy Space Center next week. Science investigations continue onboard under the guidance of the Payload Operations Center at NASA's Marshall Space Flight Center in Huntsville, AL, except for the Human Research Facility, which is monitored and controlled from the Telescience Support Center (TSC) at the Johnson Space Center, Houston. For details on ISS science, visit http://www.scipoc.msfc.nasa.gov. The International Space Station is operating in excellent shape at an altitude of 250 miles (401 km). The next ISS Status Report will be issued Wednesday, May 30, or earlier, if mission events warrant. _____________________________________________________________________ MARS ODYSSEY MISSION STATUS JPL release 23 May 2001 NASA's 2001 Mars Odyssey spacecraft performed its first trajectory correction maneuver this morning as it fired its thrusters to fine- tune its flight path for arrival at Mars in October. Odyssey fired its thrusters for 82 seconds at 10:30 AM Pacific time, which changed the spacecraft's velocity by 3.6 meters per second (8.1 miles per hour). "The maneuver executed as planned, and we are very pleased with the spacecraft performance," said David A. Spencer, mission manager for 2001 Mars Odyssey at NASA's Jet Propulsion Laboratory, Pasadena, CA. "Due to the favorable launch we received, this maneuver was much smaller than planned pre-launch. This will allow us to reach Mars with our propellant tanks nearly full, and we will make good use of the extra fuel." The principal investigator for the high-energy neutron detector instrument reports the detection of gamma ray bursts, occurring on May 8 and May 17. Comparing these measurements with similar measurements from other spacecraft allows scientists to determine the direction of the burst sources. The high-energy neutron detector and the companion neutron spectrometer instrument also detected streams of particles and radiation from enhanced solar activity on May 20. Odyssey is currently about 14.3 million kilometers (8.9 million miles) from Earth and traveling at a speed of about 29 kilometers per second (about 65,700 miles per hour) relative to the Sun. The Mars Odyssey mission is managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, Washington, DC. JPL is a division of the California Institute of Technology in Pasadena. Lockheed Martin Astronautics, Denver, built the Odyssey spacecraft. _____________________________________________________________________ STARDUST STATUS REPORT JPL release 25 May 2001 The Stardust spacecraft continues to operate in excellent condition. A project-wide workshop was held to review the entire Comet Wild 2 encounter plan, which was developed before launch, and to update this plan based upon the current understanding of the spacecraft, payload instruments, ground system, Deep Space Network and operations team actual flight performances. The participants included the Principal Investigator and most Co-Investigators, the Flight Team at Lockheed Martin Astronautics and the Management and Operations Team at JPL. Also included in the discussions were the testing and review of the updated encounter plan, including possibly using the Asteroid 5535 Annefrank close flyby opportunity. 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 8, Number 20.