MARSBUGS: The Electronic Astrobiology Newsletter Volume 8, Number 27, 16 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) HOW SMALL CAN LIFE BE? By Leslie Mullen 2) THE ORIGIN OF SEX: COSMIC SOLUTION TO ANCIENT MYSTERY By Robert Roy Britt 3) STUDENTS' HANDS-ON BIOLOGY EXPERIMENT BOUND FOR INTERNATIONAL SPACE STATION THIS WEEK NASA/MSFC release 01-230 4) NASA SCIENTIST FINDS CLUE TO POSSIBLE EVOLUTIONARY SHIFT NASA/ARC release 01-46AR 5) FREE LECTURES WILL EXPLORE VIKING LEGACY, FUTURE MISSIONS TO MARS NASA/JPL release 6) EXPLORING MARS WITH TES: A DATA USER'S WORKSHOP Arizona State University release 7) NEW ADDITIONS TO THE ASTROBIOLOGY INDEX By David J. Thomas 8) CASSINI WEEKLY SIGNIFICANT EVENTS NASA/JPL release 9) THIS WEEK ON GALILEO NASA/JPL release 10) STARDUST STATUS REPORT NASA/JPL release _____________________________________________________________________ HOW SMALL CAN LIFE BE? By Leslie Mullen From the NASA Astrobiology Institute 9 July 2001 As advanced microscopes enable us to peer deeper into the realms of inner space, biologists have been faced with a vexing question: Is there a size limit on life? If so, then just how small can something be before it can no longer be defined as "life"? Some scientists believe that life can be very small indeed. Called nanobes, nanobacteria, or nano-organisms, these miniscule structures borrow their name from their unit of measurement, the nanometer. A nanometer is one billionth of a meter. That's about the length of 10 hydrogen atoms laid out side by side. The period at the end of this sentence is approximately one million nanometers in diameter. While the tiniest bacteria measure 200 nanometers across, nanobes are even smaller. They can range anywhere from 20 to 150 nanometers long. What first caught the attention of some scientists was the way nanobes are shaped. They look remarkably like bacteria, forming spheres, chains of beads, filaments, or bean- or sausage-like shapes. Nanobes seem to share other important qualities with bacteria. For one thing, nanobes are often found grouped together in clusters. Also, some scientists claim they can grow colonies of nanobes by culturing them in the lab. The nanobes seem to spontaneously grow on metal, glass, plastic or organic surfaces which are left in water or exposed to oxygen for a few days or weeks. One scientist who firmly believes that nanobes are alive is Robert Folk of the University of Texas at Austin. In 1990, Folk discovered bacteria-like structures about 100 nanometers in size in Italian hot- spring deposits. He went public about his findings at a Geological Society of America meeting in 1992. "NASA scientist Chris Romanek heard my talk, and decided to look for nanobes in the Martian meteorite," says Folk. "He found them, and the rest is History--or Scandal, if you prefer." The discovery of nanometer-sized shapes in the Martian meteorite ALH84001 was reported in 1996 in headlines all around the world. The researchers studying the 4.5-billion-year-old meteorite said the shapes, which measured 20 to 200 nanometers across, were the fossils of Martian microbes. Was this definitive proof of ancient life on Mars--or were the structures too small to be considered "life"? To answer this question, NASA asked the National Research Council of the National Academy of Sciences to convene an expert panel. It met in late 1998 and published the report, "Size Limits of Very Small Micro-organisms." An organism able to live and reproduce on its own needs certain equipment to accomplish these tasks--and that equipment takes up space. For instance, a single ribosome, a tiny factory that cells use to make proteins, is usually 25 to 30 nanometers wide. A typical modern cell can house several hundred thousand ribosomes. Based on such life requirements, the 18 experts on the panel concluded that 200 nanometers probably marked the lowest size limit. In other words, anything smaller than 200 nanometers could not be considered "life" as we know it. "Several lines of evidence suggest that the volume of a sphere about 200 nanometers across is needed to house the chemistry of a cell that has a biology familiar to us," says Andrew Knoll, paleobiologist from Harvard University, member of the NASA Astrobiology Institute, and one of the editors of the report. "As long as molecules have volume there will be a lower limit to organism size." However, the panel also said it was possible that primitive microbes could once have been as small as 50 nanometers in diameter. "Simpler forms of life are conceivable and probably existed early in the history of life," says Knoll. "One might envision a simple cell with only one class of informational macromolecule that would fit into a 50 nanometer sphere. The key, of course, is making the distinction between cells of familiar biochemistry and cells that may exist but for which we have no direct observational knowledge." Folk disagrees with the determination of the panel, however. He believes the nanobe structures, which he says commonly range between 50 and 100 nanometers across, are viable life forms. "The limit adopted by biologists is 200 to 250 nanometers on the basis that [the structures] must be large enough to contain a DNA or RNA strand, and have the ribosomes, etc., necessary to carry on metabolism," says Folk. "My opinion is that scientists do not know enough to set arbitrary limits on life. After all, pre-Pasteur, nobody even thought there were things such as germs, and pre-1890 nobody knew there were viruses." Folk, for one, believes the nanobes in the Martian meteorite are definitely fossil structures indicative of past life. He also believes similar life forms are present in the Martian meteorite Dhofar 019, as well as the non-Martian Allende and Murchison carbonaceous meteorites. But Knoll says he knows of no reason to insist that the structures found in Martian meteorite ALH 84001 are fossils of ancient Martian life. He says the problem with these structures is not that they are too small, but rather that there is no way to tell if the structures themselves are specifically "life." Instead, they could be any number of other structures that naturally form through non-biological processes. "The size argument is a red herring if we don't know the relevant biochemistry," says Knoll. "The problem is that the structures in question are not diagnostically biological." Proof of life? Four years ago, scientists at the University of Queensland discovered nanobes in ancient Australian sandstones. Although some of the structures were as small as 20 nanometers across, the fuzzy tangles of filaments looked a lot like fungi. They also appeared to reproduce quickly, spontaneously forming dense colonies of tendrils, on Petri dishes that were exposed to oxygen and kept at 22 degrees Celsius (72 F). Laboratory analysis of the filaments repeatedly found signs of DNA (deoxyribonucleic acid). According to Philippa J.R. Uwins, one of the lead scientists of the Queensland team, all the nanobes they discovered seem to have the enzymatic and genetic material considered essential for life. Folk believes this research should have made other scientists accept the idea that life could be smaller than previously thought. "Uwins, of course, should have broken the life-barrier for biologists," says Folk. But Knoll doesn't find this example of possible nanometer-sized life to be especially compelling. Although the Queensland structures stain positively for DNA, Knoll says there are other substances that can give a "false positive" for DNA. If nanobes are ever proven to be alive, they would challenge our understanding of life on Earth. Based on everything we know about biology, it does not seem possible for modern living organisms to be smaller than 200 nanometers. "If current nanobes can be shown to be living entities, then Earth harbors life forms whose chemistry we do not understand," says Knoll. "That would be interesting." Although such a revelation would change our comprehension of life, Knoll doesn't think it would dramatically affect astrobiology. "We already acknowledge that unfamiliar life is possible," says Knoll. "I don't think that it would change the philosophy or search strategy for life detection." "Until more advanced forms are discovered, nanobacteria are astrobiology," says Folk. "Nanobacteria are the primordial life form on Earth, as well." Since his discovery of nanobes in Italian hot spring deposits, Folk says he has found nanobes in such things as bird bath scum, decayed leaves in streams, brownish water from old flower bouquets, air filters, tap and well water, hair, feces, blood, gallstones, chicken egg shells, clam shells, and teeth. He says that nanobes are virtually everywhere--one only need look for them. "I would say, cattily, that those who say 'no' [to the existence of nanobes] simply have not looked for small life forms," says Folk. "All those who have looked, have found them. Over half a dozen labs have succeeded in culturing colonies of organisms of this minute size, and some of these labs have succeeded in obtaining DNA, detecting the organic chemistry of living tissue, and even revealing structure of cell walls or membranes." Despite such assertions, Knoll maintains that those who insist nanobes are alive have yet to prove their claims. "No one has as yet convinced a skeptical microbiological community that the very small structures under discussion are living entities fully capable of self-replication," says Knoll. "Or that if they are, what novel biochemistry makes this possible." What's next While the issue of nanobes continues to be debated, the Queensland group is trying to determine the exact nature of nanobe genetic material. They also plan to analyze the growth rates of their nanobe cultures. Folk, meanwhile, is working hard to prove that the structures are widespread in nature. He is currently studying both modern and ancient rocks and minerals, as well as samples of Martian meteors, for evidence of nanobes. Folk is also conducting studies to see how nanobes may play important biological roles. "[I'm studying] the possible role of nanobacteria in symbiotically precipitating hard parts of organisms, from clam shells to dinosaur teeth," says Folk. "Also, in a joint project with the Mayo clinic, [I'm conducting] an intense study with Dr. Brenda Kirkland on [the role of nanobes in] human arterial plaque and diseased heart tissue." More information on this article is available at http://nai.arc.nasa.gov/index.cfm?page=small_life. _____________________________________________________________________ THE ORIGIN OF SEX: COSMIC SOLUTION TO ANCIENT MYSTERY By Robert Roy Britt From Space.com 10 July 2001 Comets and asteroids have been blamed for a lot of things before: shaping Earth, jumpstarting life, wiping out dinosaurs, even possibly altering human evolution. But never sex. Roughly 1 billion years after the first organisms romped in the hay, the origin of sex remains one of biology's greatest mysteries. Scientists can't say exactly why we do it, or what triggered those initial terrestrial flirtations. Before sex, life seemed to manage fine by employing asexual reproduction--the cloning of offspring without the help of a partner. Now a new study out of Caltech and NASA's Jet Propulsion Laboratory has used digital organisms to simulate life before sex and yielded a possible mechanism for instigating Earth's first courtship. Intimacy never sounded so stressful. Comet or asteroid impacts could have stressed asexual organisms enough to send them down the path of sexual reproduction after forcing a flurry of genetic mutations, the study shows. Heavy doses of radiation might also have done the trick. Get the full story at http://www.space.com/scienceastronomy/solarsystem/origin_sex_010710.h tml. _____________________________________________________________________ STUDENTS' HANDS-ON BIOLOGY EXPERIMENT BOUND FOR INTERNATIONAL SPACE STATION THIS WEEK NASA/MSFC release 01-230 10 July 2001 Students and teachers from elementary, middle and high schools in Alabama, California and Tennessee have prepared biological samples for an experiment astronauts will place aboard the International Space Station this week when the Space Shuttle Atlantis returns to that unique, orbiting laboratory. Working side-by-side with university and NASA scientists, the students mixed and loaded about 100 of the 500 biological samples in small plastic tubes that were then frozen and placed in an experiment container. The crew will transfer the experiment from the Shuttle to the Space Station during the STS-104 mission set for launch Thursday. "We are pleased to give the scientists and engineers of the future a hands-on role in biotechnology experiments on the Space Station," said Ron Porter, manager of the Biotechnology Program at NASA's Marshall Space Flight Center in Huntsville, AL. Marshall is NASA's lead center for flying payloads that take advantage of the low- gravity environment created as the Space Station orbits Earth. This will be the third trip to the Space Station for the experiment, called the Enhanced Gaseous Nitrogen Dewar--a vacuum-jacketed container, similar to a large thermos bottle that stores the samples. Since the hands-on educational project began in 1999, students and teachers from more than 500 schools in states across the country have attended workshops where they grew crystals and learned about biological substances that carry out many important functions for humans, animals and plants. The students and teachers mix biological solutions and seal the chemicals in small tubes or capillaries. The samples were frozen to -321 degrees Fahrenheit (-196 degrees Celsius or 77.3 degrees Kelvin). Just before the Shuttle launch, scientists place the samples in a dewar that has an absorbent inner liner saturated with liquid nitrogen. After Atlantis docks with the Station, the crew will move the dewar to the Space Station. After about ten days, when the nitrogen has completely boiled off and thawing is complete, the biological solutions will form crystals. When the Space Shuttle Discovery visits the Station in August, the dewar will be brought back to Earth, where scientists will retrieve and analyze the crystals to determine the structure of biological molecules. The students can view photos of the crystals grown during NASA workshops on a special Web site designed by Dr. Anna Holmes, a NASA scientist who helps conduct the workshops at the University of Alabama in Huntsville. The students can also monitor results as Dr. Alex McPherson--a biochemist at the University of California at Irvine and the lead scientist for the experiment--analyzes other crystals grown aboard the same flight. Right now, McPherson and other scientists are analyzing crystals grown on the Station in the fall of 2000 and spring of 2001. Often, higher quality crystals can be grown in the low-gravity environment created as the Space Station circles Earth. Scientists use the crystals to map the structure of macromolecules - the building blocks that make up proteins, viruses and other substances that perform critical functions in our bodies and in animals and plants. Knowledge of the precise three-dimensional molecular structure is an important tool for biochemists designing medicines. This pilot education program has been supported by the NASA Headquarters Education Office in Washington, DC; Marshall Center Biotechnology Program; University of California at Irvine; University of Alabama in Huntsville; Alabama A&M University in Huntsville; Alabama Space Grant Consortium; Florida Space Grant Consortium; Texas Space Grant Consortium; Bell South Pioneers in Tennessee; Alabama Science in Motion, a division of the Alabama Department of Education; and many other corporate and institutional sponsors. The Enhanced Gaseous Nitrogen Dewar experiment and the student experiment program are sponsored by the Microgravity Research Program Office at the Marshall Center and the Office of Biological and Physical Research at NASA Headquarters in Washington, DC. Contact: Steve Roy, Media Relations Department Phone: 256-544-0034 E-mail: steve.roy@msfc.nasa.gov News release http://www1.msfc.nasa.gov/NEWSROOM/news/releases/2001/01-230.html Photos http://www1.msfc.nasa.gov/NEWSROOM/news/photos/2001/photos01-230.htm Space Station fact sheets http://www.scipoc.msfc.nasa.gov/factchron.html#exp2fact Office of Biological and Physical Research http://spaceresearch.nasa.gov/ _____________________________________________________________________ NASA SCIENTIST FINDS CLUE TO POSSIBLE EVOLUTIONARY SHIFT NASA/ARC release 01-46AR 12 July 2001 A team of researchers, including a NASA scientist, reports that an early-life nitrogen crisis may have triggered a critical evolutionary leap about 2 billion years ago. The team, from Universidad Nacional Autonoma de Mexico (UNAM) and NASA's Ames Research Center in the heart of California's Silicon Valley, published its results in the July 5 issue of Nature. Their paper is entitled "A Possible Nitrogen Crisis for Archaean Life Due to Reduced Nitrogen Fixation by Lightning." The researchers, who simulated early Earth atmospheric conditions in a laboratory, postulate that the bacteria that existed then began producing their own nitrogen "fertilizer" in order to survive. "Our findings show how life on early Earth had to adapt to major changes in the environment," said Dr. Chris McKay, a team member from NASA Ames. "Our results indicate that a couple of billion years ago, life had to invent a way to make its own nitrogen fertilizer because the amount being produced by lightning dropped to almost zero." The UNAM-Ames researchers cite evidence that carbon dioxide was much more abundant on early Earth than it is now, and suggest that ancient lightning bolts made nitrate (in a form usable by early life) by combining oxygen from carbon dioxide with nitrogen in the atmosphere. This nitrate acted as a natural "fertilizer" for early life, providing nourishment and spurring growth, they suggest. However, because making nitrate from atmospheric nitrogen is energy intensive, the bacteria did not develop this capability on their own until the lightning source became inadequate for their needs, the research team concluded. In the lab, the team simulated conditions on early Earth over a wide range of atmospheric compositions, from mostly carbon dioxide to mostly complex nitrogen atmospheres, but always without oxygen. They used a high-power laser to simulate lightning and measured the nitrate produced. Although the temporary lapse in nitric oxide production may have lasted for only 100 million years, a relatively short period on the geologic time scale, researchers believe this was long enough to cause the ecological crisis that triggered early life's ability to "fix" its own nitrogen. "We are used to thinking of the environment and life as steady and unchanging," said McKay, "but the early Earth was quite different. Major changes in the atmosphere occurred and life had to adapt. To me, the interesting follow-up question is: Did it happen on other planets, too?" McKay said the process was triggered because, over time, carbon dioxide levels on Earth dropped and the production of atmospheric nitrate by lightning was greatly reduced. This left bacteria literally starving for nitrogen. The UNAM-NASA Ames team estimates that this environmental crisis occurred between 2 and 2.2 billion years ago. In addition to McKay, other team members included Dr. Rafael Navarro- Gonzalez and Dr. Delphine Mvondo, UNAM. NASA's Astrobiology Division in Washington, D.C. funded McKay's and NASA Ames' participation in the research project. Contact: Kathleen Burton NASA Ames Research Center, Moffett Field, CA Phone: 650/604-1731 or 604-9000 E-mail: kburton@mail.arc.nasa.gov _____________________________________________________________________ FREE LECTURES WILL EXPLORE VIKING LEGACY, FUTURE MISSIONS TO MARS NASA/JPL release 13 July 2001 A quarter of a century after successfully landing on Mars with twin spacecraft, NASA's Jet Propulsion Laboratory will treat the world to a trip down memory lane and a sneak-peak into the future with a pair of free lectures. The first lecture will also be broadcast over the Internet. Both lectures are open to the public and will start at 7:00 PM. The first will be held at JPL on Thursday, July 19, and the other at Pasadena City College on Friday, July 20. Viking 1 and Viking 2, each comprised of an orbiter and a lander, unveiled a wealth of information about the red planet. While the orbiters mapped 97 percent of the surface, both landers carried out biology experiments designed to look for possible signs of life. The results gave scientists direct measurements of enigmatic chemical activity. However, they showed no clear evidence for the presence of living microorganisms in the soil near the landing sites. "The orbital and lander data sets collected by Viking serve as the foundation upon which the next era of Mars Exploration is based," said John Callas, science manager of the Mars Exploration Rover Project and the speaker for both lectures. "The Viking legacy has enabled NASA to engage in a very ambitious campaign of exploration." The lectures will discuss the Viking legacy, highlight recent discoveries by Mars Pathfinder and Mars Global Surveyor, and describe plans for future exploration. Launched in April, the 2001 Mars Odyssey will enter Mars' orbit in October. Two rovers equipped with sophisticated instruments will launch in 2003. The rovers will land in different regions of the red planet. Lecture seating is on a first-come, first-served basis. The lecture at JPL will be held in the von Karman Auditorium, 4800 Oak Grove Dr., in Pasadena, off the Oak Grove Drive exit of the 210 (Foothill) Freeway. For directions to JPL, see http://www.jpl.nasa.gov/about_JPL/directions.html. Information on the webcast is at http://www.jpl.nasa.gov/events/lectures/jul01.html. On Friday, the lecture will be held in Pasadena City College's Forum at 1570 E. Colorado Blvd. For more information, call (818) 354-0112. Find information on the von Karman lecture series at http://www.jpl.nasa.gov/events/lectures.html or call JPL's Public Services Office at (818) 354-0112. The California Institute of Technology in Pasadena manages JPL for NASA. Contact: Enrico Piazza, 818-354-0478 _____________________________________________________________________ EXPLORING MARS WITH TES: A DATA USER'S WORKSHOP Arizona State University release http://tes.asu.edu/TESworkshop.html 14 July 2001 November 13-15, 2001 Arizona State University Tempe, AZ Conveners: Steven Ruff, Victoria Hamilton, and Philip Christensen--Arizona State University Michael Smith--NASA/Goddard Space Flight Center Michael Mellon--University of Colorado Purpose and scope There is an emerging community of scientists interested in the use of Thermal Emission Spectrometer data for exploring the surface and atmosphere of Mars. The TES data sets are both rich with potential for exciting discoveries and daunting in their scope and utilization. The tools, techniques, and knowledge that are necessary for working with TES data have been evolving since before the MGS mission and now are at a level of maturity that can be shared with the community. It is our goal to present our experience with TES data and laboratory thermal IR spectroscopy in a way that will encourage the use of both. The planned 2-day workshop is intended to be both a short course and a forum for the presentation of current TES data analysis by the community. A third (optional) day will allow attendees to visit the Granite Wash Mountains in western Arizona as part of a demonstration on the combined use of thermal IR remote sensing, field spectroscopy, and lab spectroscopy with an eye toward present and upcoming missions. This workshop is an opportunity for interested planetary scientists to learn about thermal IR spectroscopy specifically within the context of MGS TES data analysis. Although the agenda will focus on spectroscopy, non-spectral TES data sets such as thermal inertia and albedo will be discussed. The range of topics to be presented will benefit both new and more experienced users interested in Martian surface and atmospheric science. Graduate students and post-docs are encouraged to attend. A CD-ROM containing presentation materials, submitted abstracts, and some software tools will be provided. Participation and registration The workshop will be held in the newly expanded Mars Surveyor Space Flight Facility at ASU. Seating is limited to 50 people. The registration fee is $35 for the 2-day workshop and $50 for the workshop plus field trip. Indication of interest Please reply to this announcement (ruff@tes.asu.edu) with an indication of interest by August 15. Specify whether you will participate in the field trip and whether you wish to prepare an abstract of your TES data science. A second announcement for the workshop will be sent out by August 31 containing details about abstract preparation, submission, and presentation. _____________________________________________________________________ NEW ADDITIONS TO THE ASTROBIOLOGY INDEX By David J. Thomas http://www.lyon.edu/webdata/users/dthomas/astrobiology/astrobiology.h tml 16 July 2001 Articles about human space exploration and the microgravity environment http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_article s3.html L. David, 2001. Zooming in on Mars: the road to human missions. Space.com. Articles about evolutionary biology and chemistry http://www.lyon.edu/webdata/users/dthomas/astrobiology/online_article s5.html R. R. Britt, 2001. The origin of sex: cosmic solution to an ancient mystery. Space.com. R. Navarro-González, C. P. Mckay and D. N. Mvondo, 2001. A possible nitrogen crisis for Archaean life due to reduced nitrogen fixation by lightning. Nature, 412:61-64. _____________________________________________________________________ CASSINI WEEKLY SIGNIFICANT EVENTS NASA/JPL release 5-10 July 2001 The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Monday, July 9. 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/. The C27 sequence was uplinked to the spacecraft and began executing this week. Final activities in C26 included a RADAR calibration activity, an AACS reaction wheel unload, and a constraint monitor update. The RADAR activity was completed without incident and matched the results predicted by Integration Test Laboratory (ITL) testing. Initial activities in C27 included power-on of the Composite Infrared Spectrometer (CIRS), loading of Instrument Expanded Blocks for Cassini Plasma Spectrometer (CAPS), Ultraviolet Imaging Spectrometer (UVIS), Radio and Plasma Wave Science (RPWS) and Imaging Science Subsystem (ISS), an RPWS High Frequency Receiver Calibration, an AACS reaction wheel friction test, and clearing of the AACS high water marks. Observations included a Visual and Infrared Mapping Spectrometer (VIMS) Fomalhaut Observation following their Solar Port Calibration, a UVIS Interplanetary hydrogen survey, and CIRS observations of Eta Carinae and VY-Canis Majoris. Radio Science team personnel met in Rome with a group of engineers from Alenia and a representative from the Italian Space Agency. Discussions centered on the status of the KAT (Ka-Band Translator) anomaly investigation. ISS conducted an ITL test of various reset modes and Bus Interface Unit conditions to better understand the interaction of instrument flight software and camera operations. Analysis is underway. Mission Assurance submitted an Abstract for a Risk Management Session at the 2002 meeting of the IEEE. The paper entitled, "Managing Risk During Cassini Mission Operations & Data Analysis," would document the Cassini approach to Risk Management during mission operations, including the use of an on-line risk tracking system and automated metrics generation. VIMS Flight Software version 4.1 was received by Configuration Management and archived in the Project Software Library. A Delivery Coordination Meeting was held for CIMS version 1.2. This version of CIMS provided a bulk data import capability (using data formatted with XML). A June 2001 update of the Integrated Mission Operations Schedule was published to the Cassini Electronic Library (CEL)/Work Area. The schedule now covers the period from Launch through April 2005 and includes sequence development, execution and activities for the first nine tour sequences. Hardcopy distribution at JPL and Distributed Ops sites has begun. The Native file for Anomaly Response Operations Plan Rev G has been posted to the CEL and the Master Controlled Document List. The Cassini Duty roster for C27 has been updated to reflect changes in the G version. 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 release 9-15 July 2001 Cruise activities continue for the Galileo spacecraft this week. On Tuesday, the Near Infrared Mapping Spectrometer (NIMS) performs an instrument calibration using the Radiometric Calibration Target. This target is a plate that is mounted on the spacecraft and can be heated to a specific, known temperature. This allows the NIMS instrument to determine the accuracy of its heat-measuring sensors. The last such calibration was done in early April. By periodically checking out the instrument in this manner, scientists can determine accurately how the signal from the instrument is changing as the detectors age. On Friday, the spacecraft performs an Orbit Trim Maneuver (OTM), the 97th such activity planned since Galileo entered orbit around Jupiter in December of 1995, and the second of three planned for this orbit. This burn of the spacecraft's propulsive thrusters adjusts the path the spacecraft in order to reach our next close flyby of Io in early August. On Saturday, routine maintenance of the on-board tape recorder is performed. Throughout the week, the Extreme Ultraviolet Spectrometer (EUV) continues its two-month-long study of interplanetary hydrogen gas. This week's scheduled playback of data from the tape recorder includes observations from NIMS, 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). All of the data to be returned this week were recorded during the close flyby of Callisto in May. NIMS will be returning global observations of the atmosphere of Jupiter this week. SSI will be returning the highest resolution images of Callisto taken near our closest approach, which was at 138 kilometers (85 miles) altitude. 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. 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 _____________________________________________________________________ STARDUST STATUS REPORT NASA/JPL release 13 July 2001 There was one Deep Space Network (DSN) tracking pass in the past week. All subsystems are performing normally. 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. The remaining Navigation Camera guide star images were downlinked. These images looked at the exact star field that will be behind Comet Wild 2, 2.5 years from now. Before launch, it was expected that the longest effective exposure would be about 1 second, limited by attitude rates being 1 pixel per second or larger. Based upon these rates, it was expected that a perfect, uncontaminated navigation camera could see as star as dim as about 10.5 visual magnitude. We were pleased to see that the lowest attitude rate is 10 times less than predicted. Also, in one five-second exposure guide star image, at least 90 stars were identified. The dimmest was as low as 11.7 visual magnitude. There are many more star-like images that were not identified. These could be stars dimmer than 11.7 magnitude, since the star catalog that was used only went down to 11.7 visual magnitude. The power subsystem engineers have been conducting tests of the spare flight battery to simulate the expected performance when the spacecraft is at 2.4 AU. These tests indicate that we can expect approximately two hours of communications per DSN pass before the battery will need to be recharged. The pre-launch prediction was three hours of communications. The test assumed the spacecraft is at a 0.95 state of charge (SOC) when the DSN pass starts and will be at a 0.60 SOC at the end. Fault protection is activated if the SOC reaches 0.50. The expected recharge time is approximately 25 hours, matching the pre-launch prediction. 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 27.