Marsbugs: The Electronic Astrobiology Newsletter Volume 12, Number 29, 26 August 2005 Editor/Publisher: David J. Thomas, Ph.D., Science Division, Lyon College, Batesville, Arkansas 72503-2317, USA. dthomas@lyon.edu Marsbugs is published on a weekly to monthly basis as warranted by the number of articles and announcements. Copyright of this compilation exists with the editor, but individual authors retain the copyright of specific articles. Opinions expressed in this newsletter are those of the authors, and are not necessarily endorsed by the editor or by Lyon College. E-mail subscriptions are free, and may be obtained by contacting the editor. Information concerning the scope of this newsletter, subscription formats and availability of back-issues is available at http://www.lyon.edu/projects/marsbugs. The editor does not condone "spamming" of subscribers. Readers would appreciate it if others would not send unsolicited e-mail using the Marsbugs mailing lists. Persons who have information that may be of interest to subscribers of Marsbugs should send that information to the editor. _____________________________________________________________________ Articles and News 1) PROOF OF LIFE By Pamela Conrad 2) NASA STUDY SHOWS WATER COULD CREATE GULLIES ON MARS NASA/ARC release 3) CLIMATE MODEL LINKS HIGHER TEMPERATURES TO PREHISTORIC EXTINCTION National Center for Atmospheric Research release 4) PLASTIC SPACESHIPS By Patrick L. Barry Mission Reports 5) CASSINI SIGNIFICANT EVENTS FOR 11-17 AUGUST 2005 NASA/JPL release 6) DEEP IMPACT MISSION UPDATE By Lucy McFadden 7) MARS GLOBAL SURVEYOR IMAGES NASA/JPL/MSSS release _____________________________________________________________________ PROOF OF LIFE By Pamela Conrad From Astrobiology Magazine 22 August 2005 Pamela Conrad, an astrobiologist with NASA's Jet Propulsion Laboratory, has traveled to the ends of the Earth to study life. Conrad recently appeared in James Cameron's 3-D documentary "Aliens of the Deep," where she and several other scientists investigated strange creatures that inhabit the ocean floor. On June 16, 2005, Conrad gave a lecture called, "A Bipolar Year: What We Can Learn About Looking for Life on Other Planets By Working in Cold Deserts." In part 2 of this edited transcript, Conrad describes how her work in cold deserts could aid the search for alien life. If we were to find life on Mars, and that life lived in the rocks, how would we study it? You can't answer that question unless you first do some experiments on Earth. And that's what we're doing in the Arctic and in the Antarctic. In the Arctic we looked at a volcano about a 150 to 200 thousand years old, made of weathered basalt. It's very interesting weathered basalt, because it contains minerals that look very much like some of the unexplainable minerals in the controversial martian meteorite that was described to have fossilized life in it. In the Arctic site that we went to--Svalbard, Norway--there are polar bears. So when you go to the Arctic, you have to have some training in shooting. They don't want you to kill polar bears, but they want you to be able to do so if he's about to kill you. So we started our expedition to the Arctic with a half-day of gun training. It was fun shooting at paper targets, but I don't know what I'd do if I were confronted with a polar bear looking at me with dinner in his eyes. There are no polar bears in the Antarctic, but the sea life is abundant and diverse. At McMurdo Base, there are penguins, there are birds called skua, there are a couple of different types of seals. As you go farther away from the base by the shore, you get to places that are desolate. We investigated a place in the McMurdo Dry Valleys called Battleship Promontory. The rocks there are sandstone, and they were originally deposited underwater. Inside these rocks, thriving layered communities of microbes make their existence. They freeze solid during the winter and come back to life during the summer. Of course, the summer at its most exuberant heat wave only gets to be about 10 degrees Centigrade. NASA's strategy for looking for life is to first look around quickly, and process a lot of information. When you get to the interesting stuff, you might take a longer amount of time, and do it more carefully with higher resolution. You wouldn't want to do something really destructive first, because you might destroy the thing you're trying to study. You want to be as minimally invasive as possible. Some techniques are very invasive: taking a hammer and whacking on a rock and breaking it into pieces certainly makes you unable to look at the basic overall structure, the geomorphology, of that rock. So when you're looking for life in rock, if you're trying to be non- destructive, you can't crack open the rock and look inside. So there has to be some kind of clue of life on the surface of the rock. Porphyrins are a ubiquitous class of naturally occurring compounds with many important biological representatives including hemes, chlorophylls, and several others. Life anywhere is going to have some sort of electron transport or energy harnessing system. The common ones on Earth are based on porphyrins, which have very specific shapes. We would like to bring samples back from places like Mars, but right now we don't know how to do that. In the future, we will do that, but then it would be a very long experiment. We have to develop the technology to do it, we have to get to Mars safely, we have to get the samples, and we have to safely get it back. That's a complex problem. Eventually, there will be human exploration. I want to go to every cool place I can, but I don't think I'll go to Mars anytime soon. But there are a lot of people who want to go to other planets, and as we listen to the different strategies and paths that NASA takes, I'm sure that that will happen in time. Right now, I'm focussing on things that might prepare us for the type of solar system exploration that we're doing right now: sending out a spacecraft, landing it, and doing an experiment. So my team is developing strategies for life detection, using methods that are non-destructive and quick. We survey the landscape with a minimally invasive tool, we look for the contrast in the chemistry of the rock and the chemistry of organisms that might be on or in the rock. We do it in cold deserts because cold deserts are analogous to the kind of environment we find on Mars. Mars is much drier and much colder, but that's about as close as we can get here. My group has been working with an optical technique. I like to describe it as the black light you can buy at PetCo, where you shine the light on the carpet to look for dog or cat pee. Only ours is a little bit higher tech and more specific than that, because there isn't any dog or cat pee in the areas where we go. Our technique is called "laser-induced native fluorescence." You take a very short wavelength of light--an invisible wavelength deep into the ultraviolet--and you illuminate a spot. If that spot has organic molecules, that spot glows. And the color of the glow tells you something about what kind of molecule it is, how big it is, how complicated it is. And it's really cool because it's fast--you can do this in 50 microseconds. Even though ultraviolet light can be damaging, we have a very short blast. So this is a very minimally invasive technique, because it doesn't harm living things. The microbes that we've detected using this method don't die. The machine is about the size of a shoebox, and you can take it anywhere you want to immediately tell where you have life and where you don't. We've used this tool in the Arctic, sticking it into holes to determine whether or not certain minerals have any organic molecules associated with them--the specific organic molecules that might be associated with the presence of microbes. That tells us whether to grab any rocks and take them back to the lab to look for organisms. We've also used the tool on a manipulator arm of a deep- sea submersible and detected organic molecules coming out of hydrothermal vents on the sea floor. In Antarctica, the organisms live in a certain type of rock that has a lot of pore space to hold water. That means they're better able to maintain hydration. Temperatures in the rock swing, but not as wildly as the outside air because of heat that's absorbed by the rock during the day. Also, the kind of minerals that make up that rock are transparent to ultraviolet light. If the basis of your food chain is photosynthesis, then you've got be underneath a mineral that transmits light. There are different kinds of organisms that live in the rock. The kind of organism that lives in the pores spaces of rock don't go very deep--maybe a centimeter and a half if you have a really thick community. But you do see chemical evidence going a few centimeters deeper into the rock. There are other kinds of organisms that don't live in the pore spaces. They migrate into the cracks in rocks. They are called "chasmoliths." They typically do chemosynthesis, that is, they rip out chemistry associated with the rock, and they either oxidize some ion, or reduce some other ion, and this whole cycle of oxidizing something and reducing something is akin to the respiration we do. Since it doesn't involve photosynthesis, they don't need light, so they can go deeper into the rock. But the chemistry in the rock influences how deeply they can go--these tiny organisms have a community structure that has a specific set of chemical conditions that support it. If you change that set of chemical conditions, you have a whole different environment. Another limitation is you can't go too deep and use up too much space, or thermodynamically you can't continue to do chemistry because you'll drown in your own poop. That's an unfortunate state of affairs. You can tell the difference between one bacterium and another with our instrument, because different chemicals are on the surface of the organisms. Just using fluorescence can tell you the difference between basic types of bacteria. If you have a spore, and you want know what species you have, you use other techniques, like looking at the vibrational properties of the atomic bond. One of the cool things about looking for microbial life on Earth is that microbes are everywhere. Most of the biodiversity on Earth is microbial, and they can live in challenging environments. You have to give them credit for being clever in terms of coming up with adaptive strategies to cope with stressful environments. When we think of looking for fossils of past life, we tend to think of stuff like dinosaur bones. Astrobiologists don't really expect to find dinosaurs on Mars, although I do have a National Enquirer cover that differs. But you can find fossil structures in rocks, created from organisms that were in the sediment as it was being lithified-- made into a rock. You can also try to find chemical fossils, signs that there was life there. There are some chemicals that are really big molecules that are very hardy and withstand a lot. We just have to be clever enough to distinguish the chemistry associated with the rock from the chemistry associated with the living things. Read the original article at http://www.astrobio.net/news/article1687.html. _____________________________________________________________________ NASA STUDY SHOWS WATER COULD CREATE GULLIES ON MARS NASA/ARC release 24 August 2005 NASA scientists say liquid water formed recent gullies on Mars. A NASA-led team will present its Mars gully findings at the American Astronomical Society's Division for Planetary Sciences annual meeting in Cambridge, England, September 5, 2005. "The gullies may be sites of near-surface water on present-day Mars and should be considered as prime astrobiological target sites for future exploration," ventured National Research Council scientist Jennifer Heldmann, principal author of the study who works at NASA Ames Research Center in California's Silicon Valley. "The gully sites may also be of prime importance for human exploration of Mars because they may represent locations of relatively near surface liquid water, which can be accessed by crews drilling on the red planet," she added. "If liquid water pops out onto Mars' surface, it can create short gullies about 550-yards (500-meters) long," Heldmann said. "We used a computer to simulate the flow of liquid water within gully channels," Heldmann explained. "Our model indicates that these fluvially-carved gullies were formed in the low temperature and low pressure conditions of present-day Mars by the action of relatively pure liquid water." The science team found that the maximum length of gullies simulated in the computer models were comparable to the martian gullies studied. "We find that the short length of the gully features implies they did form under conditions similar to those on present-day Mars, with simultaneous freezing and rapid evaporation of nearly pure liquid water," Heldmann said. In addition, images taken by the Mars Global Surveyor spacecraft show "geologically young" small-scale features on the red planet that resemble terrestrial water-carved gullies, according to scientists. "The young geologic age of these gullies is often thought to be a paradox, because liquid water is unstable at the martian surface," Heldmann said. At present martian air pressure and temperature, water will boil and freeze at very rapid rates, the scientists reported. Team scientists noticed that images of some of Mars' gullies show that they taper off into very small debris fields--or no debris fields at all--suggesting that water rushing through the gullies rapidly froze and/or evaporated. "In the martian case, fluid well above the boiling point (which is a very low temperature at Mars' low atmospheric pressure and air temperature) is suddenly exposed to the atmosphere," said Heldmann. "The difference between the vapor and ambient pressures relative to the ambient pressure is large, and flash boiling can occur, leading to a violent loss of fluid." Scientists believe that ice probably would not accumulate in the gullies, because of the rapid evaporation of water and relatively high flow velocities, but in some cases, some ice could be carried downstream. The researchers studied computer simulations of both scenarios. "We tested our model using known flow parameters and environmental conditions of perennial saline springs in the Mars analog environment of the Canadian High Arctic," Heldmann noted. In addition to Heldmann, Chris McKay, also of NASA Ames; Brian Toon, Michael Mellon and John Pitlick, of the University of Colorado, Boulder; Wayne Pollard, of McGill University, Montreal, Canada; and Dale Andersen, of the SETI Institute, Mountain View, CA, are study co-authors. Images related to this news release may be found on the Web at: http://www.nasa.gov/centers/ames/multimedia/images/2005/marsgullies.h tml. Read the original news release at http://www.nasa.gov/centers/ames/research/exploringtheuniverse/marsgu illies.html. Additional articles on this subject are available at: http://www.spacedaily.com/news/mars-water-science-05j.html http://www.universetoday.com/am/publish/water_create_gullies_on_mars. html _____________________________________________________________________ CLIMATE MODEL LINKS HIGHER TEMPERATURES TO PREHISTORIC EXTINCTION National Center for Atmospheric Research release 24 August 2005 Scientists at the National Center for Atmospheric Research (NCAR) have created a computer simulation showing Earth's climate in unprecedented detail at the time of the greatest mass extinction in the planet's history. The work gives support to a theory that an abrupt and dramatic rise in atmospheric levels of carbon dioxide triggered the massive die-off 251 million years ago. The research appears in the September issue of Geology. "The results demonstrate how rapidly rising temperatures in the atmosphere can affect ocean circulation, cutting off oxygen to lower depths and extinguishing most life," says NCAR scientist Jeffrey Kiehl, the lead author. Kiehl and coauthor Christine Shields focused on the dramatic events at the end of the Permian Era, when an estimated 90 to 95% of all marine species, as well as about 70% of all terrestrial species, became extinct. At the time of the event, higher-latitude temperatures were 18 to 54 degrees Fahrenheit (10 to 30 degrees Celsius) higher than today, and extensive volcanic activity had released large amounts of carbon dioxide and sulfur dioxide into the atmosphere over a 700,000-year period. To solve the puzzle of how those conditions may have affected climate and life around the globe, the researchers turned to the Community Climate System Model (CCSM). One of the world's premier climate research tools, the model can integrate changes in atmospheric temperatures with ocean temperatures and currents. Research teams had previously studied the Permian extinction with more limited computer models that focused on a single component of Earth's climate system, such as the ocean. The CCSM indicated that ocean waters warmed significantly at higher latitudes because of rising atmospheric levels of carbon dioxide (CO2), a greenhouse gas. The warming reached a depth of about 10,000 feet (4,000 meters), interfering with the normal circulation process in which colder surface water descends, taking oxygen and nutrients deep into the ocean. As a result, ocean waters became stratified with little oxygen, a condition that proved deadly to marine life. This in turn accelerated the warming, since marine organisms were no longer removing carbon dioxide from the atmosphere. "The implication of our study is that elevated CO2 is sufficient to lead to inhospitable conditions for marine life and excessively high temperatures over land would contribute to the demise of terrestrial life," the authors concluded in the article. The CCSM's simulations showed that ocean circulation was even more stagnant than previously thought. In addition, the research demonstrated the extent to which computer models can successfully simulate past climate events. The CCSM appeared to correctly capture key details of the late Permian, including increased ocean salinity and sea surface temperatures in the high latitudes that paleontologists believe were 14 degrees Fahrenheit (8 degrees Celsius) higher than present. The modeling presented unique challenges because of limited data and significant geographic differences between the Permian and present- day Earth. The researchers had to estimate such variables as the chemical composition of the atmosphere, the amount of sunlight reflected by Earth's surface back into the atmosphere, and the movement of heat and salinity in the oceans at a time when all the continents were consolidated into the giant land mass known as Pangaea. "These results demonstrate the importance of treating Earth's climate as a system involving physical, chemical, and biological processes in the atmosphere, oceans, and land surface, all acting in an interactive manner," says Jay Fein, director of NSF's climate dynamics program, which funded the research. "Other studies have reached similar conclusions. What's new here is the application of a detailed version of one of the world's premier climate system models, the CCSM, to understand how rising levels of atmospheric carbon dioxide affected conditions in the world's oceans and land surfaces enough to trigger a massive extinction hundreds of millions of years ago." Read the original news release at http://www.ucar.edu/news/releases/2005/permian.shtml. Additional articles on this subject are available at: http://www.universetoday.com/am/publish/higher_temperatures_cause_pre historic_extinction.html _____________________________________________________________________ PLASTIC SPACESHIPS By Patrick L. Barry From NASA Science News 25 August 2005 After reading this article, you might never look at trash bags the same way again. We all use plastic trash bags; they're so common that we hardly give them a second thought. So who would have guessed that a lowly trash bag might hold the key to sending humans to Mars? Most household trash bags are made of a polymer called polyethylene. Variants of that molecule turn out to be excellent at shielding the most dangerous forms of space radiation. Scientists have long known this. The trouble has been trying to build a spaceship out of the flimsy stuff. But now NASA scientists have invented a groundbreaking, polyethylene-based material called RXF1 that's even stronger and lighter than aluminum. "This new material is a first in the sense that it combines superior structural properties with superior shielding properties," says Nasser Barghouty, Project Scientist for NASA's Space Radiation Shielding Project at the Marshall Space Flight Center. To Mars in a plastic spaceship? As daft as it may sound, it could be the safest way to go. Less is more Protecting astronauts from deep-space radiation is a major unsolved problem. Consider a manned mission to Mars: The round-trip could last as long as 30 months, and would require leaving the protective bubble of Earth's magnetic field. Some scientists believe that materials such as aluminum, which provide adequate shielding in Earth orbit or for short trips to the Moon, would be inadequate for the trip to Mars. Barghouty is one of the skeptics: "Going to Mars now with an aluminum spaceship is undoable," he believes. Plastic is an appealing alternative. Compared to aluminum, polyethylene is 50% better at shielding solar flares and 15% better for cosmic rays. The advantage of plastic-like materials is that they produce far less "secondary radiation" than heavier materials like aluminum or lead. Secondary radiation comes from the shielding material itself. When particles of space radiation smash into atoms within the shield, they trigger tiny nuclear reactions. Those reactions produce a shower of nuclear byproducts--neutrons and other particles--that enter the spacecraft. It's a bit like trying to protect yourself from a flying bowling ball by erecting a wall of pins. You avoid the ball but get pelted by pins. "Secondaries" can be worse for astronauts' health than the original space radiation! Ironically, heavier elements like lead, which people often assume to be the best radiation shielding, produce much more secondary radiation than lighter elements like carbon and hydrogen. That's why polyethylene makes good shielding: it is composed entirely of lightweight carbon and hydrogen atoms, which minimizes secondaries. These lighter elements can't completely stop space radiation. But they can fragment the incoming radiation particles, greatly reducing the harmful effects. Imagine hiding behind a chain-link fence to protect yourself in a snowball fight: You'll still get some snow on you as tiny bits of snowball burst through the fence, but you won't feel the sting of a direct hit from a hard-packed whopper. Polyethylene is like that chain link fence. "That's what we can do. Fragmenting--without producing a lot of secondary radiation--is actually where the battle is won or lost," Barghouty says. Made to order Despite their shielding power, ordinary trash bags obviously won't do for building a spaceship. So Barghouty and his colleagues have been trying to beef-up polyethylene for aerospace work. That's how Shielding Project researcher Raj Kaul, working together with Barghouty, came to invent RXF1. RXF1 is remarkably strong and light; it has 3 times the tensile strength of aluminum, yet is 2.6 times lighter--impressive even by aerospace standards. "Since it is a ballistic shield, it also deflects micrometeorites," says Kaul, who had previously worked with similar materials in developing helicopter armor. "Since it's a fabric, it can be draped around molds and shaped into specific spacecraft components." And because it's derived from polyethylene, it's an excellent radiation shield as well. The specifics of how RXF1 is made are secret because a patent on the material is pending. Strength is only one of the traits that the walls of a spaceship must have, Barghouty notes. Flammability and temperature tolerance are also important. It doesn't matter how strong a spaceship's walls are if they melt in direct sunlight or catch fire easily. Pure polyethylene is very flammable. More work is needed to customize RXF1 even further to make it flame and temperature resistant as well, Barghouty says. The bottom line The big question, of course, is the bottom line. Can RXF1 carry humans safely to Mars? At this point, no one knows for sure. Some "galactic cosmic rays are so energetic that no reasonable amount of shielding can stop them," cautions Frank Cucinotta, NASA's Chief Radiation Health Officer. "All materials have this problem, including polyethylene." Cucinotta and colleagues have done computer simulations to compare the cancer risk of going to Mars in an aluminum ship vs. a polyethylene ship. Surprisingly, "there was no significant difference," he says. This conclusion depends on a biological model which estimates how human tissue is affected by space radiation--and therein lies the rub. After decades of spaceflight, scientists still don't fully understand how the human body reacts to cosmic rays. If their model is correct, however, there could be little practical benefit to the extra shielding polyethylene provides. This is a matter of ongoing research. Because of the many uncertainties, dose limits for astronauts on a Mars mission have not been set, notes Barghouty. But assuming that those dose limits are similar to limits set for Shuttle and Space Station flights, he believes RXF1 could hypothetically provide adequate shielding for a 30 month mission to Mars. Today, to the dump, tomorrow, to the stars? Polyethylene might take you farther than you ever imagined. Read the original article at http://science.nasa.gov/headlines/y2005/25aug_plasticspaceships.htm. _____________________________________________________________________ CASSINI SIGNIFICANT EVENTS FOR 11-17 AUGUST 2005 NASA/JPL release 19 August 2005 The most recent spacecraft telemetry was acquired Wednesday, August 17, from the Goldstone tracking stations. The Cassini spacecraft is in an excellent state of health and is operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" web page located at http://saturn.jpl.nasa.gov/operations/present-position.cfm. Thursday, August 11 (DOY 223): Cassini's orbit passed through apoapsis today and began the 13th orbit of tour. While in the apoapsis region, the Imaging Science Subsystem (ISS) made a movie of Saturn's southern hemisphere, and the Visible and Infrared Mapping Spectrometer (VIMS) studied the rings in a mosaic. As part of sequence development for S15, the sequence leads released the preliminary cycle 1 integrated sequence products for review and for ACS Inertial Vector Propagator (IVP) & Kinematic Prediction Tool analysis. Friday, August 12 (DOY 224): A CDS flight software (FSW) patch uplink readiness review was held for the SSR auto repair correction. This patch will be uplinked in mid-September. The last time members of the Spacecraft Operations Office (SCO) looked at a time frame for the first fuel-side bipropellant repressurization planned in the tour, it appeared that it did not need to be performed until around December 2005. This repressurization is a procedure required to keep the main engine operating normally. Several changes have occurred since the last assessment: trajectory changes have increased the biprop delta-V used during the last year, as has the decision to lower the delta-V threshold for RCS thruster vs. main engine use. It is now evident that the activity should occur before OTM-33. Currently it is planned for mid-September, right before the CDS FSW patch upload. Mission Planning has been working on a maneuver cancellation process and presented the latest version to the Live IVP Update Working Group. This group has the basic science representation from Radio Science, RADAR, and the Optical Remote Sensing instruments that deal with trajectories, orbit determination deliveries, uncertainties, etc. Sunday, August 14 (DOY 226): This was the chance to hear Michael Oare's composition "Cassini's Rings" performed live in its west coast premier. A member of the Cassini flight team arranged with the composer, and with the conductor of the La Caņada Community Band, to present this piece on Sunday, August 14th, at Memorial Park in La Caņada, California. The Grafton Middle School in Yorktown, VA, originally premiered the piece at a spring concert in June of this year. SCO reported that a calibration was performed on Inertial Reference Unit-A over Sunday and Monday. Performance of the unit continues to be excellent. Monday, August 15 (DOY 227): VIMS performed an Automated Sequence Processor (ASP) command to update the command load in the instrument. This update corrects one trigger, which the science team incorrectly planned and noticed too late to correct in the S13 uplink process. The update was successfully performed. Members of the ACS and Integrated Test Laboratory teams supported and presented at the AIAA Guidance, Navigation, and Control conference in San Francisco, California the week of August 15. A calibration of the Radio Science Subsystem (RSS) HGA boresight was performed today. Instrument Operations and the Multi-Mission Image Processing Laboratory participated in extensive testing of an engineering version of FEI-5. This File Exchange Interface system is used by the MER and MRO flight projects. Their use of this system has significantly impacted Cassini and Spitzer throughput of instrument science products. Due to the architecture of a multi-mission facility, missions share resources even if they are running independent applications. For instance, the applications can be running on the same CPU, accessing the same database server and/or getting authentication from the same password server. Resources such as these may be temporarily held by one project doing its independent work. The other projects may be locked out or access restricted until the resources again become available. Testing this week involved baseline tests, problem reproducibility and problem resolution tests. The engineering version caused no adverse effects and significantly reduced the impact on Cassini. Tuesday, August 16 (DOY 228): A meeting was held today to determine if Orbit Trim Maneuver (OTM)- 28, scheduled for Thursday of this week should be cancelled. The small magnitude of the maneuver, 50 mm/sec, taken together with a resulting cost downstream of less than 1 m/sec, indicated that the maneuver was not required. This along with the necessity of the team working overnight to perform the maneuver convinced management to cancel it. All signatories have approved the Cassini Plasma Spectrometer Archive Software Interface Specification (SIS) document. Only one archive SIS remains to be completed. Near the end of this week, Cassini came within 608,000 km of Hyperion. ISS studied the satellite's geology while Ultraviolet Imaging Spectrograph measured its ultraviolet albedo. The Composite and Infrared Spectrometer (CIRS) made high spectral resolution infrared measurements for composition analysis. These results laid the groundwork for a 1010 km targeted flyby in S15. Wednesday, August 17 (DOY 229): The full merged preliminary cycle 2 products for S14 were released today. This includes files for the background sequence and the live moveable block. The associated Space Flight Operations Schedule will be released tomorrow. The final science event this week was a CIRS longitudinal scan of the rings to study seasonal effects due to elevation of the sun and screening of the rings. Additional: Outreach has released the Cassini Science Highlights for August. A reduced version of this information has been included below. Cassini Reveals Saturn's Eerie-Sounding Radio Emissions http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=589 Cassini's Latest Findings about Enceladus http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=590 Evidence of Ice Volcanism on Enceladus http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=592 Nested Craters on Mimas Tell of a Heavily Tortured Past http://saturn.jpl.nasa.gov/news/press-release-details.cfm?newsID=593 Additional articles on this subject are available at: http://www.spacedaily.com/news/cassini-05zzv.html http://www.spacedaily.com/news/cassini-05zzw.html http://www.spacedaily.com/news/cassini-05zzx.html http://www.universetoday.com/am/publish/pandora_glides_along.html?248 2005 _____________________________________________________________________ DEEP IMPACT MISSION UPDATE By Lucy McFadden NASA/JPL release 11 August 2005 The Deep Impact science team gathered in Hilo, Hawaii the last week of July for a working retreat to examine the results from Deep Impact's encounter on July 4th. Collaborating astronomers from around the world joined them both in person and via videoconference. The impact of comet Tempel 1 was scheduled to be observable from the ground while the comet was above the horizon in Hawaii, the location of some of the darkest and driest skies in the world. Many of the astronomers who used telescopes at Mauna Kea attended the workshop to learn about the impact from the Deep Impact science team's perspective, which would enable them to better interpret their own data. It was truly a collaborative effort, as the science team is interested in ground-based and space-based results to give us perspective on the Deep Impact spacecraft data. While about 50 people were present at the workshop, we had colleagues attending by videoconference in Germany, and Maryland, USA. We spanned 12 time zones, and didn't know whether to say "Good morning" or "Good Night". We settled on "Aloha" and appreciated our distant colleagues wearing their Hawaiian shirts to feel closer to the pulse of the meeting. Our tasks involved reviewing some of the most interesting data that we collected, reporting on the calibration, checking it and crosschecking, and discussing possible interpretations. We also defined additional questions we need to have answered in order to arrive at robust interpretations of the nature of the comet before impact, the phenomenon of the impact itself, and the effects of the impact afterwards. From the images posted on the web pages, it is known that the Deep Impact spacecraft returned spectacular data from the collision. Bright dust glowed and illuminated space shortly after impact. The comet zipped by and the spacecraft looked back to see what effects had been made. So much dust was kicked up by the impact, that the science team is still analyzing the images to measure the size of the crater. This analysis continues. The spectrometer showed spectral signatures of water, hydrocarbons, CO and CO2. We continue the analysis of the spectra to determine how hot the water was (between 1000 and 2000 K) and how long it remained hot. The interpretation is a challenge, because the spacecraft and the comet were in motion. That is both an advantage and a challenge. We continue to put together the story of what we saw, when, and how fast the spacecraft was moving. Initial reports from ground-based and space-based observers are varied. Some telescopes saw dramatic changes as a result of the impact, while others did not. One has to recall that the results depend not only on how large a telescope is being used, and its sensitivity, but also at what region of the spectrum the data are acquired. The physics of the impact is not active in all spectral regions. There is a lot of information to be gleaned from both positive and negative results from ground-based and space-based data. Combining those results with that of the Deep Impact spacecraft, that was right there when it happened, but carried only two types of instruments (visible imagers and an IR spectrometer) will provide an interesting scientific story when we get it all sorted out. At week's end we had compiled contributions to a manuscript to be submitted to Science magazine that is scheduled for publication in September 2005. The full set of raw and calibrated data are scheduled to be delivered to the Planetary Data System in January 2006. The Planetary Data System releases the data to the public. Read the original news release at http://deepimpact.jpl.nasa.gov/mission/update.html. _____________________________________________________________________ MARS GLOBAL SURVEYOR IMAGES NASA/JPL/MSSS release 18-24 August 2005 The following new images taken by the Mars Orbiter Camera (MOC) on the Mars Global Surveyor spacecraft are now available. Polar Polygons (Released 18 August 2005) http://www.msss.com/mars_images/moc/2005/08/18 South Polar Layers (Released 19 August 2005) http://www.msss.com/mars_images/moc/2005/08/19 The Defrosting South (Released 20 August 2005) http://www.msss.com/mars_images/moc/2005/08/20 Sediments of Arabia (Released 21 August 2005) http://www.msss.com/mars_images/moc/2005/08/21 West Argyre (Released 22 August 2005) http://www.msss.com/mars_images/moc/2005/08/22 Mars at Ls 269 Degrees (Released 23 August 2005) http://www.msss.com/mars_images/moc/2005/08/23 Valley Crossing (Released 24 August 2005) http://www.msss.com/mars_images/moc/2005/08/24 All of the Mars Global Surveyor images are archived at http://www.msss.com/mars_images/moc/index.html. 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. _____________________________________________________________________ End Marsbugs, Volume 12, Number 29.