MARSBUGS: The Electronic Astrobiology Newsletter Volume 6, Number 33, 18 October 1999. Editors: Dr. David J. Thomas, Biology and Chemistry Division, Lyon College, Batesville, AR 72503-2317, USA. Dthomas@lyon.edu or marsbugs@aol.com 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://www.lyon.edu/webdata/users/dthomas/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) GALILEO SPACECRAFT HAS HOT DATE WITH VOLCANIC MOON JPL release 2) GALILEO SUCCEEDS IN HISTORIC FLYBY OF JUPITER'S VOLCANIC MOON JPL release 3) GALILEO COMPLETES DARING IO FLYBY By Jane Platt 4) TUNGUSKA99 UPDATE By Luigi Foschini 5) CHEMISTRY OF COMET HALE-BOPP MAY OFFER CLUES ABOUT THE EARLY SOLAR SYSTEM, UMASS ASTRONOMER SAYS University of Massachusetts-Amherst release 6) NO WATER ICE DETECTED FROM LUNAR PROSPECTOR IMPACT NASA release 99-119 7) THIS WEEK ON GALILEO JPL release 8) MARS GLOBAL SURVEYOR STATUS REPORT JPL release 9) NEW MARS GLOBAL SURVEYOR IMAGE By Ron Baalke 10) MARS POLAR LANDER MISSION STATUS JPL release 11) MARS 2001 ROVER PHOTOS By Ron Baalke 12) STARDUST STATUS REPORTS JPL releases ---------------------------------------------------------------- GALILEO SPACECRAFT HAS HOT DATE WITH VOLCANIC MOON JPL release 8 October 1999 NASA's Galileo spacecraft is gearing up for a daring rendezvous with Jupiter's moon Io (pronounced EYE-oh), the most volcanic body in our solar system, on Sunday night, October 10 (Pacific Time). Galileo will swoop down to within 612 kilometers (380 miles) of Io's fiery surface at 10:06 PM PDT (1:06 PM October 11 EDT), snapping the closest-ever pictures of this intriguing celestial body. "Io is a natural laboratory for volcanoes," said Dr. Duane Bindschadler, Galileo manager of science operations and planning. "By studying Io close up, we'll learn more about how and when volcanoes erupt and why they act the way they do. This may even help us predict the behavior of volcanoes on Earth." During the flyby, Galileo's science instruments will study the chemistry, heat distribution, gravity and magnetic properties of Io. For scientists, this thrilling encounter promises to yield a bonanza of pictures and information, but for Galileo engineers, the flyby presents a serious challenge with uncertain results. Io's orbit lies in a region of intense radiation from Jupiter's radiation belts, which could affect the performance of spacecraft systems or even knock out various spacecraft instruments. A mere fraction of the dose that Galileo will receive would be fatal to a human. "We expect that the spacecraft will survive the flyby, although the radiation may cause its computers to reset or may even cause irreversible damage to critical electronic components," said Wayne Sible, Galileo deputy project manager. "There is a possibility, if enough damage is done to the electronics, it won't survive the flyby. Because of this possibility, we planned the Io encounters for the end of the two-year extended mission. After orbiting Jupiter for nearly four years, the spacecraft has more than fulfilled its mission objectives, so it seems reasonable to take a calculated risk for a much closer look at such a scientifically rich target." Galileo was originally assigned to spend two years studying Jupiter, its moons and its magnetic environment. When that original mission ended in December 1997, it was followed by a two-year extended mission, scheduled to end in January 2000. While spending the past four years near Jupiter, Galileo has been exposed to radiation on an ongoing basis, which has caused some of its instruments to act up. To prepare for any possible harm caused by radiation during the Io flyby, engineers have designed sophisticated software to help the spacecraft weed out a true crisis from a minor glitch caused by radiation and respond appropriately. Galileo, the first spacecraft to orbit Jupiter, has revolutionized our knowledge of Jupiter and its moons and has provided thousands of colorful images. Data from Galileo support the premise of a liquid ocean beneath the icy crust of Jupiter's moon Europa, an intriguing prospect since water is a vital ingredient for life. Thanks to information sent by Galileo, scientists know much more about the weather on Jupiter and the composition of its moons. En route to Jupiter, the spacecraft took the first-ever close-up pictures of asteroids, when it photographed Gaspra and Ida, and it returned historic images of the destruction of comet Shoemaker-Levy 9 as its pieces slammed into Jupiter. If all goes well with the upcoming Io flyby, the spacecraft will make an even more daring approach of Io on November 26 at an altitude of only 300 kilometers (186 miles). New Io images taken by the spacecraft are available at http://www.jpl.nasa.gov/pictures/io. Additional information and pictures taken by the Galileo spacecraft are available at the redesigned Galileo web site at http://galileo.jpl.nasa.gov. Galileo was launched from the Space Shuttle Atlantis on October 18, 1989. It entered orbit around Jupiter on December 7, 1995. The Jet Propulsion Laboratory (JPL) manages the Galileo mission for NASA's Office of Space Science, Washington, DC. The California Institute of Technology, Pasadena, CA, operates JPL for NASA. [Additional information on this article can be found at http://science.nasa.gov/newhome/headlines/ast08oct99_2.htm] ---------------------------------------------------------------- GALILEO SUCCEEDS IN HISTORIC FLYBY OF JUPITER'S VOLCANIC MOON JPL release 11 October 1999 NASA's Galileo spacecraft has successfully zipped past Jupiter's moon Io, the most volcanic body in our solar system. Instruments onboard the spacecraft peered down at Io from an altitude of only 611 kilometers (380 miles) at 10:06 PM Pacific Daylight Time on Sunday. This was the closest look at Io by any spacecraft, and Galileo's cameras were poised to capture the brief encounter. If all goes as planned, the data will be transmitted to Earth over the next several weeks and then will undergo processing by mission scientists. New pictures would then be released at a press briefing tentatively scheduled next month. "We're thrilled that the spacecraft handled this flyby so well, particularly because it had to endure a strong dose of radiation from Jupiter," said Jim Erickson, Galileo project manager at NASA's Jet Propulsion Laboratory, Pasadena, CA. "It appears at this point that everything went well." Because Io is the innermost of Jupiter's moons, it lies in a region with the highest levels of radiation from Jupiter, which can wreak havoc with spacecraft instruments. During this Io flyby, it appears the radiation did trigger an error of the onboard computer's memory, which put the spacecraft in a "safe mode," halting all non-essential activities while awaiting further commands from the ground. That occurred Sunday morning at 3:09 AM Pacific time. Galileo engineers scrambled to prepare new commands to help the spacecraft work around the problem. The commands were transmitted to the spacecraft late Sunday afternoon, they worked as hoped, and Galileo resumed full operations at 8 PM Pacific time, just two hours before the Io flyby. "It was a heroic effort to pull this off, "Erickson said. "The team diagnosed and corrected a problem we'd never come across before, and they put things back on track." "We look forward to seeing the closest-ever pictures of Io," said Dr. Duane Bindschadler, Galileo manager of science operations and planning. "We want to learn more about the differences and similarities between volcanoes on Io and volcanoes on Earth." During the flyby, Galileo's science instruments studied the surface chemistry, heat, gravity and magnetic properties of Io. The flyby took place while Galileo was 598 million kilometers (372 million miles) from Earth. A second, closer flyby of Io by Galileo is planned for the evening of November 25 Pacific time (November 26 Eastern time) at an altitude of 300 kilometers (186 miles). Additional information about the Galileo mission is available on the Galileo home page at a new web address of http://galileo.jpl.nasa.gov. JPL manages the Galileo mission for NASA's Office of Space Science, Washington, DC. The California Institute of Technology, Pasadena, CA, operates JPL for NASA. ---------------------------------------------------------------- GALILEO COMPLETES DARING IO FLYBY By Jane Platt From the JPL Universe 15 October 1999 For the men and women of the Galileo project, Sunday, October 10 began as a real nail-biter, but ended with immense pride and relief as the spacecraft successfully completed its daring flyby of Jupiter's moon Io. An unexpected 3:09 AM wakeup call on Sunday sent Galileo team members scrambling into action. Three hours after entering the intense radiation zone near Jupiter and Io, Galileo went into safing when an error popped up in the memory of the onboard computer. The team was faced with a daunting task-to get the spacecraft out of safing and back to normal operations in time for the flyby at 10:06 PM (Earth receipt time). "It was a heroic effort to pull this off," said Galileo Project Manager Jim Erickson. "The team diagnosed and corrected a problem we'd never come across before, and they put things back on track." "We waited four years for this encounter and we would do everything in our power to make it happen," said Eilene Theilig, spacecraft and sequence team chief. "Each person in this talented, dedicated and professional group knew what he or she had to do." "Before every encounter, we go through various contingency scenarios, including a possible safing," said Nagin Cox, spacecraft and sequence team deputy team chief. "That preparation paid off and the anomaly resolution team swung into action quickly." "It was poetry in motion," said Olen Adams, lead for Galileo's command and data subsystem. "People were traveling around these aisles like it was a relay race. Every single person had to perform perfectly. We could not afford one single 'gotcha.' If one person got sick, or one PC crashed, or one command didn't make it to the spacecraft, it wouldn't have worked." "I knew that if the radiation had triggered one memory fault, there was a good chance it could trigger another," said Tal Brady, who designed the command and data subsystem flight software. "I was very relieved when we got the spacecraft out of safing and later when the flyby data was recorded successfully." The team saved the day by first pinpointing the location of the computer memory error. They did this by analyzing telemetry and memory readouts and looking at the timeline of spacecraft activities. They changed the encounter sequence to avoid activities that use the faulty portion of the memory. By late Sunday afternoon, Galileo engineers uplinked a new command sequence to the spacecraft. That posed another risk, since the transmission took place while Galileo was in the deepest portion of the radiation zone near Io. Against all odds, Galileo resumed full operations at 8 PM, just two hours before the Io flyby. The spacecraft and sequence team did much of the hands-on work, in conjunction with the science and mission control teams. Erickson pointed out, "We were able to meet this enormous challenge because the other teams did their work and assured us that we were free to focus on the crisis at hand." During the flyby, Galileo's science instruments studied the surface chemistry, heat, gravity and magnetic properties of Io, the most volcanic body in our solar system, from an altitude of only 611 kilometers (380 miles). This was the closest look at Io by any spacecraft. The data, including close-up images, will be transmitted to Earth in coming weeks. "We want to learn more about the differences and similarities between volcanoes on Io and volcanoes on Earth," said Dr. Duane Bindschadler, Galileo manager of science operations and planning. A second, closer flyby of Io by Galileo is planned for November 25 at an altitude of 300 kilometers (186 miles). ---------------------------------------------------------------- TUNGUSKA99 UPDATE By Luigi Foschini http://www-th.bo.infn.it/tunguska/press1210_en.htm 12 October 1999 The first scientific results of the Italian scientific expedition, Tunguska99, will be presented at the 31st Annual Meeting of the Division for Planetary Sciences of the American Astronomical Society (Padova, Italy, October 10-15 1999). The poster will be presented in the Session 59 (late papers) on Thursday 14 october (6:00-7:30 PM). Moreover, the abstract will be published on the Bulletin of the American Astronomical Society, volume 31, number 5 (1999) and is available on the web at the Tunguska99 home page [see above]. Processing of the data is in progress, but preliminary analysis of data collected on the lake suggests that the origin of the lake be not related to the 1908 event. It constitutes, more likely, an ancient volcanic depression filled up by a more than 50 m thick sedimentary deposit of fluviatile origin. The future work will focus on the core analysis, and on the detection of possible physical effects within the sedimentary successions (i.e. gravitative failures of the slopes) that could give important insights on the energy of the event. An aerial photographic survey covering a surface of 235 km2 has been carried out. Contemporarily we measured on the ground the geographical coordinates of some points in the same area. The results of the aerial survey and topographic measurements are being processed to check whether the 1908 explosion was single or multiple and to verify a recent hypothesis on the explosion mechanism. Gamma rays from cosmic and environmental radiation have been continuously recorded on time scale of one minute and in the 0.05-3 MeV, 3-5 MeV and 5-20 MeV energy bands. The in-flight measurements indicate great gamma ray variations in dependence on altitude, longitude and latitude. Nearby the lake Cheko daughter radionuclides from the 238U and 232Th chains have been recorded. The data are being processed to find other natural or man-made radionuclides. ---------------------------------------------------------------- CHEMISTRY OF COMET HALE-BOPP MAY OFFER CLUES ABOUT THE EARLY SOLAR SYSTEM, UMASS ASTRONOMER SAYS University of Massachusetts-Amherst release 13 October 1999 A group of astronomers led by William Irvine of the University of Massachusetts has discovered that a new molecule, nitrogen sulfide (NS), is contained within comets. Although scientists have long known that the molecule exists within dense interstellar clouds, this is the first time it has been seen in a comet. The findings are being presented during the annual meeting of the Division of Planetary Sciences of the American Astronomical Society, currently underway in Padua, Italy. "The finding is significant," Irvine explains, "because astronomers believe that comets hold the best samples of materials from which the solar system was formed." Comets are icy masses that appeared in the outer regions of the solar system when it was formed, 4.5 billion years ago. Their distance from the sun has resulted in comets being heated only minimally, preserving frozen gases that may give scientists clues about what materials existed in space when the solar system formed. The astronomers made the observation in March 1997, while conducting separate research using the James Clerk Maxwell Telescope on Mauna Kea Mountain in Hawaii. Collaborators on the project were Henry Matthews, Joint Astronomy Center, in Hilo, Hawaii; Roland Meier, of the Institute for Astronomy, University of Hawaii; Irvine, Matthew Senay, and Ricardo Metz, of UMass; and Douglas McGonagle, formerly of UMass. The research was sponsored in part by NASA. The compound is the only known molecule in comets that contains both nitrogen and sulfur. The molecule is a "radical," which means that it's highly reactive, chemically. The discovery raises the question of whether the NS in Comet Hale-Bopp has existed since the start of the solar system, or if it was produced as a result of other compounds in the comet breaking apart. Scientists will be able to determine that, Irvine said, by examining exactly where in comets the NS lies. An abundance in the head, or nucleus, would suggest original material, but the amount cannot be measured from Earth. The way in which the abundance of NS varies in the comet's atmosphere, called the coma, would indicate whether the molecule is the result of other compounds breaking apart due to the effect of sunlight, or whether it was produced by chemical reactions. To make such a determination, the NS molecule must be found in other comets. The discovery is further intriguing because scientists have long suspected that many molecules on Earth were brought here by comets. "Could comets have provided molecules that became part of the oceans and the atmosphere?" Irvine asks. "Could this material perhaps even be relevant to the origin of life?" ---------------------------------------------------------------- NO WATER ICE DETECTED FROM LUNAR PROSPECTOR IMPACT NASA release 99-119 13 October 1999 The controlled crash of NASA's Lunar Prospector spacecraft into a crater near the south pole of the Moon on July 31 produced no observable signature of water, according to scientists digging through data from Earth- based observatories and spacecraft such as the Hubble Space Telescope. This lack of physical evidence leaves open the question of whether ancient cometary impacts delivered ice that remains buried in permanently shadowed regions of the Moon, as suggested by the large amounts of hydrogen measured indirectly from lunar orbit by Lunar Prospector during its main mapping mission. Research group leaders from the University of Texas at Austin announced their results today at the annual meeting of the American Astronomical Society's Division for Planetary Sciences meeting in Padua, Italy. In a low-budget attempt to wring one last bit of scientific productivity from the low-cost Lunar Prospector mission, NASA worked with engineers and astronomers at the University of Texas to precisely crash the barrel-shaped spacecraft into a specific shadowed crater. NASA accepted the team's proposal based on successful scientific peer review of the idea and the pending end of the spacecraft's useful life, although the chances of positive detection of water were judged to be less than 10 percent. Worldwide observations of the crash were focused primarily on using sensitive spectrometers tuned to look for the ultraviolet emission lines expected from the hydroxyl (OH) molecules that should be a by-product of any icy rock and dust kicked up by the impact of the 354- pound spacecraft. "There are several possible explanations why we did not detect any water signature, and none of them can really be discounted at this time," said Dr. Ed Barker, assistant director of the university's McDonald Observatory at UT Austin, who coordinated the observing campaign. These explanations include: * the spacecraft might have missed the target area; * the spacecraft might have hit a rock or dry soil at the target site; * water molecules may have been firmly bound in rocks as hydrated mineral as opposed to existing as free ice crystals, and the crash lacked enough energy to separate water from hydrated minerals; * no water exists in the crater and the hydrogen detected by the Lunar Prospector spacecraft earlier is simply pure hydrogen; * studies of the impact's physical outcome were inadequate; * the parameters used to model the plume that resulted from the impact were inappropriate; * the telescopes used to observe the crash, which have a very small field of view, may not have been pointed correctly; * water and other materials may not have risen above the crater wall or otherwise were directed away from the telescopes' view. Although the crash did not confirm the existence of water ice on the Moon, "this high-risk, potentially high- payoff experiment did produce several benefits," said Dr. David Goldstein, the aerospace engineer who led the UT Austin team. "We now have experience building a remarkably complex, coordinated observing program with astronomers across the world, we established useful upper limits on the properties of the Moon's natural atmosphere, and we tested a possible means of true 'lunar prospecting' using direct impacts." Lunar Prospector was launched on January 6, 1998, from Cape Canaveral Air Station, FL, aboard an Athena 2 rocket. In March 1998, mission scientists announced their first tentative findings of the presence of water ice in shadowed craters near the Moon's south and north poles. They estimated later that up to six billion metric tons of water ice may be buried in these craters under about 18 inches of soil, in more concentrated deposits than originally thought. However, the evidence was indirect, they cautioned, based on reasonable scientific assumptions given the levels of hydrogen detected, from which water ice is inferred. Since then, Prospector data have also been used to develop the first precise gravity map of the entire lunar surface. While the Moon's magnetic field is relatively weak, Prospector has confirmed the presence of local magnetic fields that create the two smallest magnetospheres in the Solar System. Another scientific landmark is the assembly of the first global maps of the Moon's elemental composition. The $63 million Lunar Prospector mission was led by Dr. Alan Binder of the Lunar Research Institute, Tucson, AZ, and managed by NASA's Ames Research Center in Moffett Field, CA. Lockheed Martin Missiles & Space, Sunnyvale, CA built it. Other participating organizations included the Department of Energy's Los Alamos National Laboratory, NM, and NASA's Goddard Space Flight Center, Greenbelt, MD, and Jet Propulsion Laboratory, Pasadena, CA. [More information on this article is available at http://science.nasa.gov/newhome/headlines/ast13oct99_1.htm] ---------------------------------------------------------------- THIS WEEK ON GALILEO JPL release 12-17 October 1999 Now that Galileo has sucessfully completed its historic, closest-ever encounter with Io this past weekend, Galileo now turns its attention to returning to Earth the plethora of data gathered during the flyby and stored on its onboard tape recorder. During playback, data are read into the spacecraft's computers for processing, packaging and transmission to Earth. Observations performed by the Near-Infrared Mapping Spectrometer and the Fields and Particles instruments are on this week's playback schedule. Small amounts of ride-along data recorded by the Photopolarimeter Radiometer during these observations are also included on this week's data. Data playback is interrupted twice this week. On Wednesday, the spacecraft performs a standard gyroscope performance test. On Friday, the spacecraft will execute a flight path adjustment, if needed. It appears that before the Io flyby, the intense radiation in the area caused an error in the memory on Galileo's onboard computer. This caused the spacecraft to enter safe mode, but engineers scrambled to get it functioning fully in time for the flyby. When observations performed by the Solid-State Imaging camera (SSI) during the flyby are transmitted to Earth, those data may access the same area of memory that caused the encounter anomaly. Flight controllers here on Earth are in the process of examining the onboard computer's memory to devise a strategy for returning SSI data without causing the spacecraft to enter safe mode. As soon as they do that, the Io close-ups will be returned to Earth. The first set of data is returned by the Fields and Particles instruments and comes from a 65-minute high resolution recording of the environment (plasma, dust, and electric and magnetic fields) surrounding Io, including electromagnetic waves and radio signals. These data will assist scientists with studies of the Io ionosphere and its interaction with the Jovian magnetosphere. In particular, they will contribute to a better understanding of particle dynamics near Io, and thermal and non- thermal plasma interaction in the region. The Near-Infrared Mapping Spectrometer follows on the schedule with the return of various observations of Io's surface. The first three captured the Loki, Pele, and Pillan volcanic regions while they were on Io's night side. Taken in darkness, the observations were designed to search for thermal emissions from the volcanic calderas. The remaining seven observations captured regions on Io's dayside. The dayside nature of the observations allows the Near-Infrared Mapping Spectrometer to gather data describing the composition of the surface. Two observations are returned of each of the Colchis, Prometheus, and Zamama regions. The remaining observation captures the Tohil region. The Prometheus and Zamama regions contain volcanic vents, while the Tohil and Colchis features are mountains, whose geological structure, origin and history are presently unknown. ---------------------------------------------------------------- MARS GLOBAL SURVEYOR STATUS REPORT JPL release 7 October 1999 Launch / Days since Launch = Nov 7, 1996 / 1065 days Start of Mapping / Days since Start of Mapping = April 1, 1999 / 189 days Last Orbit Covered by this Report = 2603 Total Orbits = 4285 Total Mapping Orbits = 2603 Recent events The mm007 sequence has completed execution. The mm008 sequence has been uplinked to the spacecraft and is now active as of Thursday October 7. The mm008 sequence is a six week long sequence and will continue to execute through November 17. HGA anomaly The HGA inner gimbal is currently at 76.19 degrees and is now coming back down. The maximum angle was 76.2 degrees, occurring late on DOY 279. The inner gimbal angle will continue decreasing, reaching the location of the gimbal obstruction at 41.5 deg in early February. Work is currently underway to implement a new mapping data collection and return plan to maximize our science data return for the remainder of the nominal mapping mission. Spacecraft health All subsystems continue to report nominal status. Uplinks There have been 17 uplinks to the spacecraft during the last week, including the mm008 sequence, new star catalogs and ephemeris files, and instrument command loads. Total command files radiated to the spacecraft since launch is 3955. Upcoming events The mm009 sequence development kickoff meeting is scheduled for November 2, with uplink preliminary scheduled for November 15. ---------------------------------------------------------------- NEW MARS GLOBAL SURVEYOR IMAGE By Ron Baalke 8 October 1999 The following new image taken by the Mars Global Surveyor spacecraft is now available. Autumn Frost, North Polar Sand Dunes The image resides on the Mars Global Surveyor web site at http://mars.jpl.nasa.gov/mgs/msss/camera/images/index.html The image caption is appended below. Mars Global Surveyor was launched in November 1996 and has been in Mars orbit since September 1997. It began its primary mapping mission on March 8, 1999. Mars Global Surveyor is the first mission in a long-term program of Mars exploration known as the Mars Surveyor Program that is managed by JPL for NASA's Office of Space Science, Washington, DC. Malin Space Science Systems (MSSS) and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO. Mars Global Surveyor Mars Orbiter Camera Autumn Frost, North Polar Sand Dunes MGS MOC Release No. MOC2-184, 8 October 1999 Autumn in the martian northern hemisphere began around August 1, 1999. Almost as soon as northern fall began, the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) started documenting the arrival of autumn frost--a precursor to the cold winter that will arrive in late December 1999. The first features to become covered by frost were the sand dunes that surround the north polar ice cap. The dunes seen here would normally appear very dark--almost black--except when covered by frost. Why the dunes begin to frost sooner than the surrounding surfaces is a mystery: perhaps the dunes contain water vapor that emerges from the sand during the day and condenses again at night. This picture shows dunes near 74.7°N, 61.4°W at a resolution of about 7.3 meters (24 feet) per pixel. The area covered is about 3 km (1.9 mi) across and is illuminated from the upper right. The picture appears to be somewhat fuzzy and grainy because the dunes here are seen through the thin haze of the gathering north polar winter hood (i.e., clouds). Image credit: NASA/JPL/Malin Space Science Systems. ---------------------------------------------------------------- MARS POLAR LANDER MISSION STATUS JPL release 11 October 1999 Flight controllers for NASA's Mars Polar Lander mission have set October 20 as the date of the next thruster firing that will fine-tune the spacecraft's path for its December 3 arrival. The spacecraft is healthy and operating normally. On Saturday, October 9, the spacecraft's fault protection software placed the lander in a safe standby mode in response to an errant interaction between attitude control software and the commands under which the spacecraft was operating at the time. The flight team successfully returned the spacecraft back to normal operations within the day. Extensive analysis of spacecraft data by the flight teams at NASA's Jet Propulsion Laboratory in Pasadena, CA, and Lockheed Martin Astronautics in Denver, CO, has confirmed that the lander does not have the same unit conversion error that contributed to the loss of the Mars Climate Orbiter last month. The Mars Polar Lander team has spent the last several weeks planning the early lander mission that will use the spacecraft's radio transmitter to communicate directly with Earth. The team is also working on a plan to use the currently orbiting Mars Global Surveyor spacecraft as a communications relay. Project managers believe all of Polar Lander's science objectives will be met. This week, the team is in the process of testing and training for the early mission phase on the Martian surface. Engineers are also re-examining all of the simulations and tests used to validate the entry, descent and landing phase of the mission. Mars Polar Lander is currently 23.6 million kilometers (14.7 million miles) from Mars, approaching the planet at a speed of 4.6 kilometers per second (10,300 miles per hour) relative to the planet. ---------------------------------------------------------------- MARS 2001 ROVER PHOTOS By Ron Baalke 15 October 1999 Recent photos of the Mars 2001 rover undergoing engineering tests with the robotics arm at JPL are now available on the Mars Surveyor 2001 home page at http://mars.jpl.nasa.gov/2001/rover/testbed/gallery.html The Mars Surveyor 2001 Lander is scheduled for launch on April 10, 2001. It will land on Mars on Jan. 22, 2002 and touch down near the Martian equator. The 2001 Lander will carry an imager to take pictures of the surrounding terrain during its' rocket- assisted descent to the surface. The Lander will also be carrying a spare Mars Pathfinder rover, a robotic arm and several other science instruments, including three that will return data in support of eventual human exploration. Hardware on the Lander will be used for an in-situ demonstration test of rocket propellant production using gases in the Martian atmosphere. Other equipment will characterize the Martian soil properties and surface radiation environment. ---------------------------------------------------------------- STARDUST STATUS REPORTS JPL releases 8 October 1999 The Stardust spacecraft continues to perform normally with the flight team at Lockheed Martin Astronautics (LMA) concentrating on downlinking science and engineering data as well as sending commands needed to go to All Stellar attitude control during the next few weeks. This is the last week in cruise sequence SC009 with cruise sequence SC010 starting next Monday. A problem with the Navigation Camera Engineering Model (NCEM) in the LMA Spacecraft Test Laboratory (STL) has been traced to a bad cable connection. The final testing of the priority inversion flight software patch and the Navigation Camera retest sequence have now been initiated with a fully operational STL including the NCEM. The Stardust operations and science team met with the Deep Space 1 Project to obtain "lessons learned" from their asteroid flyby as related to our comet flyby. Camera calibration, sequence testing in STL and flight and contingency planning were some of the major highlights of the discussion. The Education and Public Outreach activities continue at a high and productive level. The Request for Proposal for managing the current "Education Fellows" Program has been released by JPL. Also Stardust is supporting the NASA Office of Space Science Exhibit at the California Science Teachers Association Conference in Long Beach, California which expects to have over 20,000 participants. In the area of Technology Transfer, the production of carbon aerogel for testing of the Mars Non-Ablative Aeroshell has begun. A new technique for accomplishing the gelation of the precursor resorcinol-formaldehyde organic wet gels has been developed. 15 October 1999 The Stardust spacecraft continues to perform normally in cruise sequence SC010. The flight team at Lockheed Martin Astronautics (LMA) had multiple communications sessions with the spacecraft during the past week with successful tests with All-Stellar mode, first in a Dual Mode and then in a Stand-alone mode. In Dual Mode, both the IMU's (Intertial Measurement Unit) and Star Camera are producing attitude knowledge and control data, but the IMU is controlling the spacecraft attitude. This mode is used to validate that the attitude position and angular rate information produced by the Star Camera are consistent with the IMU-produced data. In Stand-alone mode, the Star Camera controls the spacecraft attitude. Both tests went very well, and after detailed analyses of the telemetry data from these tests are completed within a month or so, the spacecraft will be ready to go to All-Stellar attitude knowledge and control as the normal attitude mode. A detailed calibration of the Low Gain Antenna (LGA) with the spacecraft being over 2 Astronomical Units from the Earth was also completed successfully. In this test, the LGA was off- pointed from Earth at a wide range of angles to measure the signal strength throughout this off-pointing angle range. The results of this calibration will be used to predict the communications link performance in any of the LGA pointing orientations expected during the remainder of the mission. 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 Vol. 6, No. 33