MARSBUGS: The Electronic Astrobiology Newsletter Volume 8, Number 28, 23 July 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) NASA CELEBRATES 25TH ANNIVERSARY OF MARS LANDING NASA release 01-143 2) WATER SHAPED MARTIAN LANADSCAPE IN RECENT TIMES, UA HYDROLOGIST SAYS By Lori Stiles 3) HAPPY ANNIVERSARY, VIKING LANDER By Tony Phillips 4) SURVIVAL OF THE FLATTEST From SpaceDaily 5) NEW ADDITIONS TO THE ASTROBIOLOGY INDEX By David J. Thomas 6) CASSINI WEEKLY SIGNIFICANT EVENTS NASA/JPL release 7) CASSINI PROGRAM ANNOUNCES TWO NEW SLIDE SETS AVAILABLE ON THE WEB! NASA/JPL release 8) THIS WEEK ON GALILEO NASA/JPL releases 9) MARS ODYSSEY MISSION STATUS NASA/JPL release 10) STARDUST STATUS REPORT NASA/JPL release _____________________________________________________________________ NASA CELEBRATES 25TH ANNIVERSARY OF MARS LANDING NASA release 01-143 17 July 2001 Twenty-five years ago, on July 20, 1976, NASA's Viking 1 lander soft- landed on the surface of Mars, becoming the first successful mission to land on the Red Planet, as well as the first successful American landing on another planet. With a second lander later joining the first on the surface and with two orbiters circling the planet, the Viking project changed our understanding of that alien world. Its treasure trove of images and data covering the entire Martian globe remains a valuable scientific resource for the study of Mars. Thursday, July 19, NASA Administrator Daniel S. Goldin delivers the keynote address at "Continuing the Quest--Celebrating Viking and Looking to the Future of Mars Exploration," a symposium hosted by Lockheed-Martin Corp. at the National Geographic Society's Grosvenor Auditorium, Washington, DC, from 1:00 PM to 5:30 PM EDT. NASA's Langley Research Center, Hampton, VA, hosts a panel discussion, titled "Viking: The First Encounter," at Langley's Reid Conference Center, Friday, July 20, from 1:30 PM to 3:00 PM EDT. This event will be broadcast live on NASA Television. The Viking 1 lander operated on the Plain of Chryse (Chryse Planitia) until November 1982. The Viking 2 lander set down on the Plain of Utopia (Utopia Planitia) on September 3, 1976, and operated until April 1980. The two landers took 4,500 unprecedented images of the surrounding surface and more than three million weather-related measurements, while the two orbiters took 52,000 images representing 97 percent of the Martian globe. Viking will probably be most remembered for its search for life on Mars. Each lander contained a suite of biology instruments designed to detect evidence of life in the Martian soil. Scientists concluded that the Viking experiments found no evidence of life at either landing site, but didn't rule out the possibility that life may have existed in the past or may still exist in other, more hospitable, places. "The Viking landing sites are extremely dry desert environments where it would be unlikely to find present-day biological activity on the surface," said Dr. Jim Garvin, Mars Program Scientist at NASA Headquarters, Washington, DC. "Other sites on Mars, such as nearer the polar caps or other places where liquid water may be found, are far more likely places to look for signs of present or past life. Our long-term plans call for missions to find liquid water on or under the surface, which will be the best places to begin a search for signs of life." NASA's Langley Research Center was responsible for managing Project Viking. "We didn't really knows what Mars was all about. Mars had been examined from orbit by the Mariners and we had a pretty good picture, but the images were on the scale of a football field," said Viking Project Manager James Martin. "That was the smallest thing we could see and that's not very distinct when you consider the landers are only in the order of six or eight feet across. We didn't have the slightest idea what was on the surface in that scale." In April 1978, Langley turned Project Viking over to NASA's Jet Propulsion Laboratory (JPL), Pasadena, CA. Today, JPL manages the Mars Exploration program, a two-decade-long effort to answer fundamental questions about Mars' early evolution and its ability to support life. Since Viking, NASA's missions to Mars have included the ill-fated Mars Observer, the successful Mars Pathfinder lander and Sojourned rover, the prolific Mars Global Surveyor (still operating in orbit around Mars), and the Mars Climate Orbiter and Mars Polar Lander, both of which failed as they neared Mars. The 2001 Mars Odyssey explorer is more than halfway to the Red Planet and is due to arrive in orbit on October 23. In 2003, NASA plans to launch twin geology-laboratory rovers to the surface, each the size of a desk and capable of travelling up to 110 yards a day from their landing site. Other missions, including landers and orbiting missions, will follow every 26 months. More information about NASA's Mars Exploration program is available on the Internet at http://mars.jpl.nasa.gov. Contacts: Donald Savage Headquarters, Washington, DC Phone: 202-358-1753 Mary Hardin Jet Propulsion Laboratory, Pasadena, CA Phone: 818-354-5011 Ivilesse Gilman Langley Research Center, Hampton, VA Phone: 757-864-6122 Joan Underwood Lockheed-Martin Astronautics Corp., Denver, CO Phone: 303-971-7398 An additional article on this subject is available at http://www.space.com/news/spacehistory/rethinking_viking_010720- 1.html. ____________________________________________________________________________________ WATER SHAPED MARTIAN LANADSCAPE IN RECENT TIMES, UA HYDROLOGIST SAYS By Lori Stiles, University of Arizona 19 July 2001 Scientists have known for decades that Mars, at least in its ancient past, has had a considerable amount of water. But when Mars Global Surveyor began mapping the Red Planet in sharp detail early in 1999, it disclosed startling evidence that water has shaped Martian landforms within the past 10 million years. The discovery challenges the prevailing view that Mars' surface has remained extremely cold and dry--much as it is today--for the past 3.9 billion years. It confirms the idea that internal heat periodically triggers short- term warmer and wetter conditions - conditions conducive to life--in the global Martian hydrological cycle, University of Arizona Regents' Professor Victor R. Baker says in a review article, "Water and the Martian landscape," published by Nature July 12. Baker is head of the UA department of hydrology and water resources. Mars is cold, dry and quiet for long periods of the hydrological cycle, periods spanning hundreds of millions of years, Baker says. It becomes actively warmer and wetter during brief episodes that last perhaps thousands to tens of thousands of years. He summarizes evidence of permafrost and ground ice, surface water and glacial ice seen first in early 1970s images from Mariner 9 flybys and in later 1970s images from the Viking missions. New results from Mars Orbital Camera (MOC) and Mars Orbiter Laser Altimeter (MOLA) are not only consistent with the view that water shaped the geology of Mars - they say it happened very recently. New spacecraft images have revealed: * Megafloods that have possibly triggered climate change within the past 10 million years * Extensive, uncratered (young) areas of the northern plains and southern highlands covered by contraction-cracked, polygonal terrain that closely mimics terrestrial permafrost areas * Lakes that held water for a thousand to ten thousand years, when climate must have been drastically different than it is now. * Gullies that have drained water and debris on Mars' surface within the past several million years * A whole assembly of features that is evidence for very recent glaciers--crevasse-like fractures, moraines drained by converging tributaries, debris aprons deposited within the past several million years. To speculate a bit, Baker said in an interview, the latest water- active episode is so recent that it may not yet be over. Current cold, dry Mars may be just a phase within one of the rare, brief warm and wet periods. "We don't know the answer to that yet--that's very speculative, " Baker said. "But if it's true, it would have major implications for sending people to Mars, because it may mean that water is more available than otherwise thought." UA planetary scientist William V. Boynton's Gamma Ray Spectrometer (GRS) heading to Mars on the Mars Odyssey spacecraft will begin its 917 Earth-day mapping mission in December 2001 or January 2002. The GRS will map the amounts of all the elements over the entire surface of Mars. Hydrogen would signal the presence of water or ice buried as deep as a meter in Mars' dust. Other high-resolution spectrometers, cameras and robotic devices now in the planning stages also will search for Martian water, Baker said. When scientists have learned as much as possible from these remote sensing instruments, one idea is to send a number of small, simple and inexpensive surface penetrators to be dropped at several places on the planet to test for the presence of water. For now, however, new images from the Mars Orbital Camera and Mars Orbital Laser Altimeter further confirm that "brief episodes of water-related activity, including glaciation, punctuate the geological history of Mars," Baker wrote in Nature. Evidence for recent Martian glaciers is among the most important and controversial, he said. "If there are glaciers, then Mars is very different than many people have described it," he said. "Glaciers aren't ice cubes, sitting there to waste away. In order to have glaciers, you have to have precipitation. Water has to move through the atmosphere, and it precipitates and makes the ice grow." And glaciers don't form in the coldest environments, he added. Glaciers form where there is cold and moisture. "But for there to be moisture, it can't be supercold," he noted. "The atmosphere has to be warm enough to evaporate water and move it through the air. The presence of glaciers means that Mars once was a lot warmer, and that there was much more water on the Martian surface. The presence of glaciers suggests that there must have been standing bodies of water as well." How could it happen? Confronted by Viking images of young fluvial and glacial features on Mars--stream valleys that apparently were formed by precipitation and glacial features over large areas of the planet, Baker, Robert G. Strom and other UA scientists in 1991 theorized what has become known as the "MEGAOUTFLO" model. Basically, the hypothesis says that over the long term, water and volatiles remain frozen as ground ice and ground water in the subsurface because Mars is so distant from the sun and extremely cold. The perennially frozen permafrost acts like a cap on a soda bottle. And just as gas and water in a capped soda bottle explode when heated, sporadic bursts of internal planetary heat trigger the dramatic release of gas and water locked under the permafrost. They theorize that so much water is released in such episodes that a temporary ocean forms repeatedly over the northern hemisphere. Massive Martian volcanism near the northern hemisphere's Thasis Bulge has--and may again--trigger an ocean. Carbon dioxide released to the atmosphere promotes the warming greenhouse effect so that liquid water is stable near the Martian surface. Mars lacks a soil layer like Earth's, so when it rains, water filters underground rather than collecting on the surface. Local valleys and other observed Martian features form when near- surface water gushes up from below. But when it rains, water removes carbon dioxide from the atmosphere, and Mars chills to the point that permafrost reforms, plunging the planet into another dry, frigid long-lasting epoch. The extensive hydrosphere implied by Mars' water-generated geology "may exist only as ground ice in the thick permafrost zone and as underlying groundwater," Baker wrote in Nature. "Yet, this is the type of environment in which the extremophile progenitors of Earth's biosphere probably evolved. Indeed, early Mars provided an arguably better habitat for the inception and incubation of early life than did early Earth." And if that's the case, he added, there could be fossils. An additional article on this subject is available at http://spaceflightnow.com/news/n0107/20marswater/. _____________________________________________________________________ HAPPY ANNIVERSARY, VIKING LANDER By Tony Phillips 20 July 2001 Twenty-five years ago NASA's Viking 1 lander made history by descending from orbit to the surface of Mars. It was the first probe from Earth to land intact on the Red Planet, and the first American spacecraft to land on any world since the Apollo program. Before Viking 1 touched down many people thought Mars might harbor abundant plant life and microbes living among the rust-colored rocks. Scientists guessed the skies might be tinged deep purple like Earth's stratosphere, which is about as tenuous as the Martian atmosphere. But Viking 1 and its sister ship Viking 2, which arrived on Mars a few months later, quickly dispelled those notions. The landers revealed an alien world with sterile soil and eerie salmon-pink skies. No plants swayed in the breeze. No animals scurried from rock to rock. On the bright side, there were no hostile aliens either. If there was to be a "War of the Worlds"--like the one popularized by Orson Welle's famous 1938 radio broadcast--it wouldn't likely begin on Mars! The Viking 1 lander set down on Chryse Planitia, a flood plain at 23 degrees north latitude. "Chryse Planitia is an interesting place," says Jim Garvin, Mars program scientist at NASA Headquarters. "Long ago--perhaps billions of years--it was the dumping ground for five wide outflow channels apparently carved by flowing water." Scientists were attracted to it because of its watery history. Viking mission planners liked it because it was flat and seemed to offer a safe landing spot. "[Before Viking], Mars had been examined from orbit by the Mariner spacecraft... but the images were on the scale of a football field," explains former Viking project manager James Martin of NASA's Langley Research Center. "That was the smallest thing we could see and that's not very distinct when you consider the landers are only six or eight feet across. We didn't have the slightest idea what was on the surface [at such small scales]." Landing anywhere was risky! Nevertheless, Viking 1 touched down safely and transmitted its first image 25 seconds later. The lander's seismometer failed to uncage, and a sampler arm locking pin was stuck and took 5 days to shake out. Otherwise, all the experiments functioned as planned. The lander went about its business for more than six years, from July 20, 1976 until November 1982, substantially exceeding its design lifetime of 90 days! On September 3, 1976, Viking 2 set down at Utopia Planitia--a gently- sloping plain half a world away from the Viking 1 site (6725 km, to be exact). "Viking 2 landed at 48 degrees north latitude near the Mie crater," says Garvin. "It was a very different environment from the flood plains of Chryse." The weather at Utopia Planitia was different--a result of its more northern latitude, there were curious pedestals that scientists thought might be small volcanoes, and the terrain was littered with the ejecta of the nearby impact crater. "It was a bold move," says Garvin. Indeed, Viking 2 settled with one leg on a rock tilted at 8 degrees. Nevertheless, the lander performed well for nearly four Earth-years. Mission controllers shut it down on April 11, 1980, after its batteries failed. Like its sister ship, Viking 2 was powered by long-lasting radioisotope thermoelectric generators, or RTG's for short. RTG's create electricity from heat given off by the natural decay of plutonium. Such a power source allowed long-term science investigations that otherwise would not have been possible. (RTG's also power the distant Pioneer 10 spacecraft, which is still alive after almost 30 years in space.) Working steadily for years, the two landers accumulated 4,500 up- close images of the Martian surface. They also collected more than three million weather-related measurements--including the first in situ observations of a global Martian dust storm. Meanwhile, two Viking mission orbiters circling high above the planet snapped 52,000 images covering 97 percent of the Martian globe. The Viking landers were successful in so many ways, but they may be remembered best as the first space probes to conduct on-the-spot biological tests for life on another planet. The experiments discovered puzzling chemical activity in scooped-up samples of Martian soil--but there was no clear evidence of living microorganisms. Perhaps that's not surprising. \ Garvin explains, "Mars has a thin atmosphere and no global magnetic field, so its surface is constantly bombarded by cosmic rays, solar flares, and harsh ultraviolet (UV) light from the Sun." UV radiation produces oxygen ions at the Martian surface that destroy organic molecules. "The sampling arm on the Viking landers dug down only about 22 cm," says Garvin. That might not have been deep enough to reach the "safe zone" for tiny Martian life. Both of the Viking lander sites were extremely dry desert environments. "Other sites on Mars, such as nearer the polar caps or other places where liquid water may be found, are perhaps more likely places to look for signs of present or past life," speculates Garvin. "Our long-term plans call for missions to find liquid water on or under the surface, which will be the best places to begin looking for signs of life." Since the Viking program, NASA's missions to Mars have included the ill-fated Mars Observer, the successful Mars Pathfinder lander and Sojourner rover, the prolific Mars Global Surveyor (still operating in orbit around Mars), and the Mars Climate Orbiter and Mars Polar Lander--both of which failed as they neared the Red Planet. The 2001 Mars Odyssey spacecraft is now more than halfway to Mars and is due to arrive there on October 23rd. Operating from orbit, the Odyssey spacecraft will not only search for signs of underground water and interesting surface minerals, but also it will test the radiation environment to learn if Mars is safe for humans. The next pair of landers to visit Mars are scheduled to leave Earth in mid-2003 and to arrive on Mars early the following year. Unlike the Viking landers, however, the 2003 Mars Exploration Rovers won't be confined to their landing sites. The mobile geology laboratories- -each the size of a desk and capable of traveling up to 110 meters a day--will roam the Martian terrain analyzing rocks and soil. Like most Mars missions, the rovers will begin their interplanetary journey when Earth and Mars are close together. Every 26 months the distance between Earth and Mars shrinks as their orbits bring them together. Astronomers call the time around closest approach "opposition." NASA plans to take advantage of as many Mars oppositions as possible to send probes to the Red Planet roughly every two years. Future missions on the drawing board include longer-lasting and more capable rovers, reconnaissance orbiters-- maybe even Mars-exploring airplanes and balloons. Perhaps one day we humans will go ourselves! And when we arrive we'll find a pair of dusty pioneers already there--the long-lasting, prolific, but now-silent Viking landers. They blazed the trail for all who followed. More information on this article is available at http://science.nasa.gov/headlines/y2001/ast20jul_1.htm?list52260. _____________________________________________________________________ SURVIVAL OF THE FLATTEST From SpaceDaily 23 July 2001 Darwinian dogma states that in the marathon race of evolution, the genotype that replicates the fastest, wins. But now scientists at the California Institute of Technology say that's true, but when you factor in another basic process of evolution, that of mutations, it's often the tortoise that defeats the hare. It turns out that mutations, the random changes that can take place in a gene, are the wild cards in the great race. The researchers found that at high mutation rates, genotypes with a slower replication rate can displace faster replicators if the former has a higher "robustness"--or fitness--against mutations; that is, if a mutation is, on average, less harmful to the slower replicator than to the faster one. Get the full story at http://www.spacedaily.com/news/life-01z.html. _____________________________________________________________________ NEW ADDITIONS TO THE ASTROBIOLOGY INDEX By David J. Thomas http://www.lyon.edu/webdata/users/dthomas/astrobiology/astrobiology.h tml 23 July 2001 Articles about astrobiology, exobiology and terraformation http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_article s1.html L. David, 2001. Rethinking Viking: the life on Mars debate rages on. Space.com. J. Foust, 2001. Does the red planet have liquid water today? Spaceflight Now. T. Phillips, 2001. Happy anniversary, Viking lander. NASA Science News. Articles about the search for extraterrestrial intelligence (SETI) http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_article s4.html N. Lubick, 2001. Looking for aliens. Scientific American. Articles about evolutionary biology and chemistry http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_article s5.html L. Mullen, 2001. How small can life be? SpaceDaily. H. Sparks, 2001. Nitrates, lightning key to life at early Earth. Space.com. SpaceDaily, 2001. NASA scientist finds clue to possible evolutionary shift. SpaceDaily. SpaceDaily, 2001. Survival of the flattest. SpaceDaily. _____________________________________________________________________ CASSINI WEEKLY SIGNIFICANT EVENTS NASA/JPL release 12-18 July 2001 The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Monday, July 16. The Cassini spacecraft is in an excellent state of health and is operating normally. Information on the spacecraft's position and speed can be viewed on the "Present Position" web page at http://www.jpl.nasa.gov/cassini/english/where/. Recent spacecraft activities include a clearing of the Attitude and Articulation Control Subsystem (AACS) Highwater Marks, a Magnetospheric Imaging Instrument (MIMI) Low Energy Magnetospheric Measurement Subsystem (LEMMS) sensor power cycle, and a Radio Frequency Subsystem (RFS) static phase error test. The Reaction Wheel Assembly (RWA) system was unloaded and powered off, and the spacecraft switched to Reaction Control Subsystem (RCS) control as planned. As part of a Periodic Instrument Maintenance activity, the Radio Science Subsystem (RSS) team executed a High Gain Antenna (HGA) boresight calibration and Ultra Stable Oscillator (USO) characterization. The Radio and Plasma Wave Science (RPWS) instrument performed a High Frequency Receiver (HFR) calibration, and the Ultraviolet Imaging Spectrometer (UVIS) performed two interplanetary hydrogen surveys. The Imaging Science Subsystem (ISS) successfully executed its first observations of Saturn along with some star calibrations, and the Visual and Infrared Mapping Spectrometer (VIMS) performed a Pleiades observation. The Instrument Operations/Multimission Image Processing Laboratory (IO/MIPL) team created and delivered 362 ISS image products of Saturn and stars. The main body of Saturn is about 40 pixels across in the Narrow Angle Camera (NAC) image, and about 90 pixels across when Saturn's rings are included. Titan is also visible and was calculated to be 1.6 pixels across. For comparison, if the NAC were viewing Saturn from Earth, the main body would be about 16 pixels across. Additionally, IO/MIPL created and delivered 220 VIMS cube products of stars. The Huygens Mission Recovery Task Force (HRTF) held its eighth meeting at the European Space Research & Technology Centre in Noordwijk, Holland. The agenda for this last meeting was to prepare the final report and to consolidate follow-on actions for the JPL and European Space Agency (ESA) teams that will implement the new Huygens mission. The Attitude Control Flight Software Development team delivered version A8.3.2 of the AACS Flight Software (FSW) to the Integrated Test Lab (ITL) for further testing. This is the second point build for A8.3, which is the FSW build the Spacecraft Operations Office (SCO) is using for critical sequence development. The VIMS team delivered version 4.1 FSW to the Project Software Library. An ITL test of the newly delivered flight software was conducted to produce data to validate the new MIPL ground software that will process data generated by the FSW. Analysis of the data processing is underway. An in-depth Critical Design Review (CDR) of Cassini Tour Downlink Operations Concepts was held as the first in a series of reviews to present Cassini readiness for Tour. Additionally, a dry-run presentation was held in preparation for the next CDR, which will review the Cassini Ground Data System. System Engineering and MSSO personnel worked with the Cassini Information Management System (CIMS) developers to identify several new procedures to increase user access capabilities to the CIMS Web Server. A kaleidoscopic movie made from about 1,200 Jupiter images taken by Cassini revealed unexpectedly persistent polar weather patterns on the giant planet, and was featured on the CNN web site at http://www.cnn.com/2001/TECH/space/07/17/jupiter.storms.reut/index.ht ml. Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, CA, manages the Cassini mission for NASA's Office of Space Science, Washington, DC. _____________________________________________________________________ CASSINI PROGRAM ANNOUNCES TWO NEW SLIDE SETS AVAILABLE ON THE WEB! NASA/JPL release 22 July 2001 The Cassini Program announces two new slide sets available on the web! "A Trip to Saturn" chronicles the assembly, launch, and journey of Cassini-Huygens to the Saturn System. "The Saturn System" is a compilation of images of Saturn, its moons, rings, and magnetospheres as seen through Voyager and the Hubble Space Telescope. A Trip to Saturn http://www.jpl.nasa.gov/cassini/english/pic/trip2saturn.html The Saturn System http://www.jpl.nasa.gov/cassini/english/pic/saturnsystem.html Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, CA, manages the Cassini mission for NASA's Office of Space Science, Washington, DC. _____________________________________________________________________ THIS WEEK ON GALILEO NASA/JPL releases 16-22 July 2001 Standard cruise activities continue for the Galileo spacecraft this relatively quiet week. On Monday, the spacecraft performs routine maintenance on the propulsion system. On Thursday, the spacecraft is turned 3.9 degrees to keep the communications antenna pointed towards Earth. In the realm of real-time science data collection, the Extreme Ultraviolet Spectrometer (EUV) continues its two-month-long study of interplanetary hydrogen gas. Just to keep things interesting, on Wednesday and Thursday the spacecraft appears to pass within approximately 0.5 degree of Earth's Moon, as seen from the ground communications antennas. When this happens, the Moon can actually be "seen" by the antennas, which are tracking the spacecraft, and can interfere with the radio signal from Galileo. This effect is not nearly as severe as that seen when the spacecraft and Sun are close together in the sky, but we still make sure that no valuable telemetry is being sent during the time period when communications are affected. Not all of the complications that govern how a spacecraft is operated are caused by situations in the remote reaches of the solar system! As part of the continuing playback of data stored on the on-board tape recorder during Galileo's May flyby of Callisto, the data expected this week are from the Solid State Imaging camera (SSI) and the suite of Fields and Particles instruments that measure the magnetic field environment of Jupiter. These instruments are the Energetic Particle Detector (EPD), Heavy Ion Counter (HIC), Magnetometer (MAG), Plasma instrument (PLS), and Plasma Wave Subsystem (PWS). SSI will be returning the highest resolution images of Callisto ever obtained. They were taken near our closest approach, which was at 138 kilometers (85 miles) altitude. In addition, stereo pictures of a domed crater will be played back. The Fields and Particles data were recorded during a period of approximately one hour centered on the closest approach to Callisto, and will help to study the interactions between the solid body of Callisto and the electromagnetic fields and plasmas of Jupiter's magnetosphere. In addition, these data will add to our understanding of Callisto's own magnetic field. Like Europa, Callisto displays an induced magnetic field, possibly due to the presence of substantial liquid water within a hundred kilometers (62 miles) or so of its icy surface. 23-29 July 2001 With two weeks to go before the next flyby, activities on the spacecraft are relatively quiet, while activities on the ground are heating up. The flight team of scientists and engineers are busy putting the final touches on the series of commands that will govern Galileo as it skims past Io on August 5. On Friday, the spacecraft performs routine maintenance on the propulsion system. The Extreme Ultraviolet Spectrometer (EUV) is continuing its two- month-long study of interplanetary hydrogen gas. This activity will conclude just before the start of encounter operations. During the past two weeks, the Dust Detector instrument (DDS) has seen a dramatic increase in the number of dust impacts that it measures. During this cruise period the normal interval between data read-outs from the DDS instrument is 20 days. The spacecraft team has sent commands to read out DDS data approximately once every three days during this period of high activity, which is expected to last one more week. Playback of the data recorded during Galileo's May flyby of Callisto is nearly 60% complete. This week, playback data are expected from the Solid State Imaging camera (SSI), the Near Infrared Mapping spectrometer (NIMS), and the suite of Fields and Particles instruments that measure the magnetic field environment of Jupiter. These instruments are the Energetic Particle Detector (EPD), Heavy Ion Counter (HIC), Magnetometer (MAG), Plasma instrument (PLS), and Plasma Wave Subsystem (PWS). The SSI data are from Callisto global color images and stereo images taken near closest approach. For the most part, these are samples of the frames, and the imaging team will use these samples to determine the best choice of processing and compression parameters to use on the next pass through the data. NIMS data return includes global color observations of Io, observations of a hot spot in Jupiter's atmosphere and of an area in the wake of the Great Red Spot, and an observation of the Asgard impact basin region on Callisto. In addition, earlier data sampled from the NIMS Io eclipse observation revealed new, high-temperature volcanic activity at a location in high southern latitudes where no volcanic activity had been detected before. NIMS is replaying about 1 minute of data from this observation with a greater data density (larger number of spectral samples) in order to better resolve both the location and the temperature of the new eruption. The Fields and Particles playback data were taken at the closest approach to Callisto. 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 ____________________________________________________________________________________ MARS ODYSSEY MISSION STATUS NASA/JPL release 16 July 2001 At 8:30 AM Pacific time today, NASA's 2001 Mars Odyssey spacecraft passed the halfway point on its journey to Mars. It has been 100 days since Odyssey's launch and 100 days remain until it arrives at the red planet. "Odyssey is now closer to Mars than Earth. The spacecraft is healthy and all systems are looking good," said David A. Spencer, the Odyssey mission manager at NASA's Jet Propulsion Laboratory. "Planning for Mars approach and orbit insertion in October is our primary focus right now." The navigation team reports the spacecraft is right on course. To date, the Deep Space Network has taken 11 separate measurements using the so-called delta differential one-way range measurement, a technique that uses two ground stations to determine the angular position of the spacecraft relative to the known position of a quasar. The measurements provide the navigation team with an additional source of information, adding confidence to their estimates of the Odyssey flight path. Today, Odyssey is 45.8 million kilometers (about 28.5 million miles) from Earth and 30 million kilometers (about 19 million miles) from Mars, traveling at a velocity of 26 kilometers per second (58,000 miles per hour) relative to the Sun. The Mars Odyssey mission is managed by JPL 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. Contact: Mary Hardin, 818-354-0344 ____________________________________________________________________________________ STARDUST STATUS REPORT NASA/JPL release 20 July 2001 There was one Deep Space Network (DSN) tracking pass this week and all subsystems are performing normally. The spacecraft continues excellent operations. The Cometary and Interstellar Dust Analyzer (CIDA) instrument continues to observe the interstellar dust stream with an optimal spacecraft attitude when not in communication with Earth. Plans are being develop to take additional Navigation Camera images. These images will be similar to the recent images that were taken weekly to monitor the camera's performance. One of the last images detected about 90 stars and stars as dim as about visual magnitude 12 as accurately as about 0.1 pixels 1-sigma. The next images will be the last full frame images taken for nearly a year, due to power constraints, as the Stardust trajectory takes the spacecraft out to 2.7 AU (about 400 million kilometers, or 250 million miles) in April 2002. Minor flight software patches continue to go well except for the Navigation Camera pattern matching and windowing software that was originally to be part of the flight software capability delivered before launch. This flight software will allow an expected image pattern of stars, planets, comets and/or asteroids to be sent to the spacecraft. Only small image windows around this pattern will be sent to the ground, reducing the amount of imaging data by 1000 or more. Such a capability would allow us to continue imaging stars, planets or asteroids deep into the main asteroid belt. The spacecraft test laboratory (STL) computer is an aging SGI Onyx that has difficulty handling the additional burdens of testing the Navigation Camera's flight software, such as simulating and processing images. A search is underway to find a newer, more capable SGI Challenger computer that uses the same operating system, minimizing any transition impact. 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 28.