Marsbugs: The Electronic Astrobiology Newsletter Volume 10, Number 38, 23 September 2003 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, except for specific articles, in which instance copyright exists with the author/authors. 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. 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 from the Marsbugs web page at http://www.lyon.edu/projects/marsbugs/. ________________________________________________________________________ CONTENTS 1) PLANETARY PRIMER: MARS AND VENUS By Laurance R. Doyle 2) ASTRONOMERS IDENTIFY A "PLANET-SWALLOWING" GIANT STAR University of Sydney release 3) CHINA TO LAUNCH FIRST ASTRONAUTS AFTER NATIONAL DAY By Hou Yi 4) OCEAN PLANT LIFE SLOWS DOWN AND ABSORBS LESS CARBON NASA/GSFC release 5) CHOMPING ON NANO-NUGGETS By Leslie Mullen 6) FIRST SUPERNOVAE QUICKLY SEEDED UNIVERSE WITH STUFF OF LIFE Harvard-Smithsonian Center for Astrophysics release 03-21 7) WHY SHOULD WE GO THERE--NEW CONTEST! By Maggie Zubrin 8) EARLY MARS WAS FROZEN BUT HABITABLE, PART II From Astrobiology Magazine 9) SCIENTISTS PRACTICE MARS DRILLING NEAR ACIDIC SPANISH RIVER NASA/ARC release 03-74AR 10) NEW ADDITIONS TO THE ASTROBIOLOGY INDEX By David J. Thomas 11) CASSINI SIGNIFICANT EVENTS NASA/JPL release 12) THE FINAL DAY ON GALILEO NASA/JPL release 13) GALILEO--END OF MISSION By Ron Baalke 14) GALILEO END OF MISSION STATUS NASA/JPL release 2003-129 15) MARS GLOBAL SURVEYOR IMAGES NASA/JPL/MSSS release 16) MARS ODYSSEY THEMIS IMAGES NASA/JPL/ASU release 17) STARDUST STATUS REPORT NASA/JPL release ________________________________________________________________________ PLANETARY PRIMER: MARS AND VENUS By Laurance R. Doyle From Astrobiology Magazine 16 September 2003 Of the nine planets in our solar system, the closest to Earth are Mars (about 50-percent farther from the Sun) and Venus (about 30-percent closer). Venus' surface temperature is about 900 degrees Fahrenheit (482 degrees Celsius), whereas a warm day on Mars is like one of the cooler days in Antarctica. What happened to these planets to make them so inhospitable for biological organisms as we know them? Carbon dioxide is a greenhouse gas, which means it traps warmth in the form of infrared radiation like a gaseous "blanket" over a planet's atmosphere. Earth's oceans contain about 60 times more carbon dioxide than its atmosphere. In fact, carbon dioxide gas makes up very little (less than 1 percent) of the Earth's atmosphere. The rest is made up of about three-fourths nitrogen, one-fourth oxygen, some argon, carbon dioxide and other trace gases. However, the small amount of carbon dioxide is essential for keeping Earth warm. It works with the water vapor in the atmosphere to keep Earth's oceans from freezing. By dissolving carbon dioxide and re- releasing it into the atmosphere, the oceans can be thought of as controlling the temperature of our planet (this process is, of course, much more complex). If all the carbon dioxide in our oceans were released at once, our atmosphere would become unbearably hot. The same effect would take place if humans released too much carbon dioxide into the atmosphere by polluting processes such as the internal combustion engine. (Pollution has increased the amount of carbon dioxide in our atmosphere by at least 25 percent in the last 150 years.) Some scientists believe that Venus had an ocean. According to the theory, Venus was too close to the Sun to maintain it. When water vapor reached the upper atmosphere, the ultraviolet light from the Sun would break it into its components--oxygen and hydrogen--the latter of which escaped into space. As Venus' oceans were evaporating, their carbon dioxide was released into the atmosphere, which caused increasing heat, which, in turn, caused increasing evaporation, and so on. This is called the "runaway greenhouse effect" and is the reason why Venus is so hot today. Mars, on the other hand, may have been just right for habitability during the early days of the solar system. It likely had a great ocean, lakes and thermal vents. This is why so many scientists are interested in looking for fossils there. But unlike Earth, Mars does not have plate tectonics--the recycling of the continents that is so active on Earth. A nail left outside will rust; it will turn into iron oxide. When it rusts, it takes a bit of oxygen out of the air. Rocks do this also, forming all sorts of compounds with oxygen and other gases as constituents. Then why don't rocks deplete our air supply? Because rocks on Earth are recycled. The movement of the continents folds the rocks deep into Earth's crust, re-melting and vaporizing them, thus re-releasing the oxygen and other atmospheric constituents they contain back into our atmosphere. However, this process of continental folding requires a heat source to keep it going. Our planet's heat source consists of the radioactive decay of heavy elements such as uranium and thorium deep within Earth. So what happened on Mars? Mars is about one-tenth the size (mass) of Earth and therefore cooled much faster (as smaller things do). If Mars had much plate tectonic activity it has long since stopped, as the interior of Mars cooled more rapidly than Earth's did. Mars was not able to recycle its rocks and so its atmosphere is mostly "trapped" within them today. Without much of an atmosphere to keep it warm, Mars remains a very cold place--too cold, and with too sparse an atmosphere, to allow liquid water to persist on its surface. Thus we have two very interesting examples of how our neighborhood planets work. Mars lets us appreciate our planet's continual recycling (we can learn to build structures that withstand earthquakes, and stay away from volcanoes, but the planet still needs them to operate effectively). Venus, on the other hand, warns us to avoid carbon dioxide pollution if we want to keep our planet at the nice, cool liquid water temperature it now has. What would have happened if Venus had been located in Mars' orbit? If this was the case, we might have had two habitable, liquid- water planets in our solar system today. Our immediate planetary neighbors are thus studies in appreciating how neatly our own planet works. Are there other ways a planet-sized body might work to make a nice place to live? What's next? Orbital projections of where Mars Express and the Mars Exploration Rovers are, right now, can be continuously monitored over their half- year journeys at http://orbits.esa.int/orbits/science/app/mexp.htm and http://mars.jpl.nasa.gov/mer/mission/spiritrightnow.html, respectively. Read the original article at http://www.astrobio.net/news/article595.html. ________________________________________________________________________ ASTRONOMERS IDENTIFY A "PLANET-SWALLOWING" GIANT STAR University of Sydney release 16 September 2003 Astronomers from Sydney University have come forth with a solution to a mysterious new object recently discovered in our Milky Way. In a letter soon to be published in the journal, Monthly Notices of the Royal Astronomical Society, Dr. Alon Retter and Dr. Ariel Marom from the Department of Physics suggest that this phenomenon is an expanding giant star swallowing nearby planets, an event which may one day befall our own planet. Their research provides data to support the theory that the multi-stage eruption of the "red giant" known as V838 Monocerotis observed last year was fuelled as it engulfed three near orbiting planets. This could be the first evidence for an event that had been predicted but not known to have been observed so far. The work identifies a new group of objects with stars that swallow planets. Astronomers had previously been unable to explain a spectacular explosion that transformed a dim innocuous star into the brightest cool supergiant in the Milky Way. The event was originally discovered by Australian amateur astronomer, Nicholas Brown in January 2002, when V838 Monocerotis suddenly became 600,000 times more luminous than our Sun. In an ordinary nova explosion, the outer layers of a compact star are ejected into space, exposing the super hot core where nuclear fusion was taking place. By contrast, V838 Monocerotis increased enormously in diameter and its outer layers cooled and were very disrupted but still conceal the giant's core. Beautiful images taken by the Hubble Space Telescope showed evidence of a previous eruption that ejected material from this object in the past. This too is very unusual. The Sydney team suggests that the outburst of V838 Monocerotis took place as it swallowed three massive Jupiter-like planets in succession. Evidence for this is provided through study of the shape of the light curve and comparison between the observed properties of the star and several theoretical works. In their scenario, in addition to the gravitational energy generated by the process, there may also have been a rapid release of nuclear energy as "fresh" hydrogen was driven into the hydrogen burning shell of the post-main sequence star. Interestingly past studies have also suggested that the inner planets in our solar system, Mercury, Venus and maybe even Earth, should be eventually swallowed by the Sun. Previous research has proposed that this is in fact a common characteristic and that many giant stars have consumed planets during their evolution. The current work suggests that the engulfment of a massive planet can cause an eruption of the host star. Explaining the methods used during their study, Dr. Retter said, "The careful inspection of the light curve of V838 Monocerotis showed that the three peaks have a similar structure, namely each maximum is followed by a decline and a very weak secondary peak. The shape of the light curve prompts us to argue that V838 Mon had three events of similar nature, but probably of different strengths. The obvious candidate for such behavior is the swallowing of massive planets in close orbits around a parent star." According to this work, there should be more examples of expanding giants that swallow less and lighter planets thus showing weaker and less spectacular eruptions. Contact: Jacob O'Shaughnessy Media Officer Phone: +61 2 9351 4312 Alon Retter Phone: +61 2 9351-4058 E-mail: retter@physics.usyd.edu.au Read the original news release at http://www.usyd.edu.au/news/newsevents/articles/2003/sep/16_star.shtml. An additional article on this subject is available at http://www.universetoday.com/am/publish/giant_swallowing_planets.html. ________________________________________________________________________ CHINA TO LAUNCH FIRST ASTRONAUTS AFTER NATIONAL DAY By Hou Yi 16 September 2003 China is set to send its yuhangyuan ("astronaut") into space in October with the liftoff to occur by the middle of the month, Wen Wei Po in Hong Kong reports today (September 15). Unidentified sources told the newspaper that the countdown to launch the historic manned Shenzhou-5 mission (SZ-5, Shenzhou means "Divine Vessel" or "Magic Vessel") would enter the one month mark as of today. Chinese space officials have decided that the launch would happen after the week long celebration of the National Day on October 1. However, no specific launch date will be chosen until after the holiday. Unconfirmed information from the Xi'an Satellite Control Center (XSCC) in Shaanxi Province said that the single-person mission might see its launch on October 10. Read the full article at http://www.spacedaily.com/news/china-03za.html. An additional article on this subject is available at http://www.spacedaily.com/2003/030916112710.3lssg42r.html. ________________________________________________________________________ OCEAN PLANT LIFE SLOWS DOWN AND ABSORBS LESS CARBON NASA/GSFC release 16 September 2003 Plant life in the world's oceans has become less productive since the early 1980s, absorbing less carbon, which may in turn impact the Earth's carbon cycle, according to a study that combines NASA satellite data with NOAA surface observations of marine plants. Microscopic ocean plants called phytoplankton account for about half the transfer of carbon dioxide (CO2) from the environment into plant cells by photosynthesis. Land plants pull in the other half. In the atmosphere, CO2 is a heat-trapping greenhouse gas. Watson Gregg, a NASA GSFC researcher and lead author of the study, finds that the oceans' net primary productivity (NPP) has declined more than 6 percent globally over the last two decades, possibly as a result of climatic changes. NPP is the rate at which plant cells take in CO2 during photosynthesis from sunlight, using the carbon for growth. The NASA funded study appears in a recent issue of Geophysical Research Letters. "This research shows ocean primary productivity is declining, and it may be a result of climate changes such as increased temperatures and decreased iron deposition into parts of the oceans. This has major implications for the global carbon cycle," Gregg said. Iron from trans- continental dust clouds is an important nutrient for phytoplankton, and when lacking can keep populations from growing. Gregg and colleagues used two datasets from NASA satellites: one from the Coastal Zone Color Scanner aboard NASA's Nimbus-7 satellite (1979- 1986); and another from Sea-viewing Wide Field-of-view Sensor data on the OrbView-2 satellite (1997-2002). The satellites monitor the green pigment in plants, or chlorophyll, which leads to estimates of phytoplankton amounts. The older data was reanalyzed to conform to modern standards, which helped make the two data records consistent with each other. The sets were blended with surface data from NOAA research vessels and buoys to reduce errors in the satellite records and to create an improved estimate of NPP. The authors found nearly 70 percent of the NPP global decline per decade occurred in the high latitudes (above 30 degrees). In the North Pacific and North Atlantic basins, phytoplankton bloom rapidly in high concentrations in spring, leading to shorter, more intense lifecycles. In these areas, plankton quickly dies and can sink to the ocean floor, creating a potential pathway of carbon from the atmosphere into the deep ocean. In the high latitudes, rates of plankton growth declined by 7 percent in the North Atlantic basin, 9 percent in the North Pacific basin, and 10 percent in the Antarctic basin when comparing the 1980s dataset with the late 1990s observations. The decline in global ocean NPP corresponds with an increase in global sea surface temperatures of 0.36 degrees Fahrenheit (F) (0.2 degrees Celsius (C)) over the last 20 years. Warmer water creates more distinct ocean layers and limits mixing of deeper nutrient-rich cooler water with warmer surface water. The lack of rising nutrients keeps phytoplankton growth in check at the surface. The North Atlantic and North Pacific experienced major increases in sea surface temperatures: 0.7 degrees C (1.26°F) and 0.4 degrees C (0.72°F) respectively. In the Antarctic, there was less warming, but lower NPP was associated with increased surface winds. These winds caused plankton to mix downward, cutting exposure to sunlight. Also, the amount of iron deposited from desert dust clouds into the global oceans decreased by 25 percent over two decades. These dust clouds blow across the oceans. Reductions in NPP in the South Pacific were associated with a 35 percent decline in atmospheric iron deposition. "These results illustrate the complexities of climate change, since there may be one or more processes, such as changes in temperature and the intensity of winds, influencing how much carbon dioxide is taken up by photosynthesis in the oceans," said co-author Margarita Conkright, a scientist at NOAA's National Oceanographic Data Center, Silver Spring, MD. Other recent NASA findings have shown land cover on Earth has actually been greening. For information and images on the Internet, visit http://www.nasa.gov/home/hqnews/2003/jun/HQ_03182_green_garden.html. Read the original news release at http://www.gsfc.nasa.gov/topstory/2003/0815oceancarbon.html. An additional article on this subject is available at http://www.spacedaily.com/news/oceans-03c.html. ________________________________________________________________________ CHOMPING ON NANO-NUGGETS By Leslie Mullen From Astrobiology Magazine 17 September 2003 Nanobacteria are not alive, but instead are the result of enzymes that break down organic material, according to a new study published in the journal Geology. Eight years ago, features resembling bacteria and measuring 20 to 100 nanometers across were discovered in the martina meteorite ALH84001. NASA scientists interpreted these features to be the fossilized remnants of ancient life, but many scientists rejected that conclusion. A nanometer is one millionth of a millimeter. The period at the end of this sentence is about one million nanometers long. The tiniest bacteria measure about 200 nanometers in size, and many believe that life can't get much smaller than that. A committee formed under the auspices of the US National Academy of Sciences determined that, due to the size requirements of such vital elements as enzymes and genetic material, organisms smaller than 200 to 300 nanometers in diameter could not be self-sustaining and therefore could not be considered to be "life." Others contend that life can be that small, and as proof they claim to have grown nanobacteria in the laboratory. In addition to the nanobacteria in the martian meteorite, spheroidal features measuring 50 to 200 nanometers have been found in sedimentary rocks on Earth. Some claim that these spheroids are the fossilized remains of once living nanobacteria. The new study, conducted by Jürgen Schieber of Indiana University in Bloomington and Howard Arnott of the University of Texas at Arlington, suggests an alternative explanation for nanometer-sized features. The scientists report that protein balls measuring 40 to 120 nanometers across are produced when bacterial enzymes cause organic material to decay. Schieber and Arnott dipped tiny pieces of bean, squid and beef into the muck from a pond, to ensure that the samples became coated with the full spectrum of naturally occurring decay bacteria. The samples were then buried in clay to simulate the burial of organic matter in sedimentary rock. Over the next two weeks, the researchers found the tissue samples experienced "explosive" bacterial growth, and balls measuring 40 to 120 nanometers in size were widespread. The scientists say that these "nannoballs" compare well with published examples of nanobacteria. "Because gradual decay of tissues always led to formation of nannoballs, we surmised that the latter resulted when microbial enzymes interacted with the buried samples," the scientists write. The scientists also exposed tissues to various purified protein-degrading enzymes in separate experiments, and this confirmed that such enzymes were responsible for the nannoballs. The enzymes snip the larger tissue elements like cell walls and muscle fibers into nanometer-sized units. Once snipped, the tissues contract into balls due to elastic forces. This enzymatic breakdown of organic matter may act as an aid to decomposition, the scientists suggest, reducing material to bite-sized nuggets for bacteria to ingest. "Bacteria are osmotrophs and can only take in dissolved molecules liberated by exoenzymes utilized outside of the cell," write the scientists. "Seeing no subunits smaller than our nannoballs, we assume that in the subsequent degradation step, the nannoballs are broken down by further enzyme action into soluble molecules that can be ingested by bacteria." Nannoballs are not always consumed by bacteria, say the scientists, because under certain conditions the tissues can become mineralized. This mineralization preserves the nannoballs, turning them into fossils in just a few weeks. Although the nannoballs are not fossilized life forms, they can act as "biomarker" evidence for bacterial life. "Most if not all alleged nannobacterial structures in sedimentary rocks are probably by-products of bacterial degradation of organic matter and not evidence for minute life forms called nannobacteria," the scientists conclude. "Nonetheless, mineralized nannoballs may indicate bacterial enzyme action on organic tissues and serve as a visual proxy for microbial activity." Kathie Thomas-Keprta, an astrobiologist with Lockheed Martin at NASA's Johnson Space Center, has studied the magnetite and carbonate mineralogy of the martian meteorite ALH84001. She says that if microbes on Earth produce nannoballs as they degrade certain minerals, as they do with the tissues in this new study, then the nannoball-like texture observed on the surface of carbonate globules in ALH84001 may be a product of such microbial etching. However, she says it's still possible that the features in ALH84001 are the fossilized remains of microbial life. Part of the problem with the debate over the size constraints of life, says Thomas-Keprta, is that microbes can shrink substantially after death. "The size of a viable organism may be vastly different from the size of that organism when fossilized or mineralized," she states. "We do not understand how the size of organisms changes with fossilization or mineralization, nor do we know if particular categories of organisms can be better preserved than others." While the physical shape and size, or morphology, of a structure is not enough to determine whether it was once a living microorganism, certain surface textures might be evidence of past biological activity. A granular surface texture composed of nannoballs, in conjunction with other biomarkers, may provide further evidence of past microbial life. Research article citation: Schieber, J. and Arnott, H. J., 2003. Nanobacteria as a by-product of enzyme-driven tissue decay. Geology, 31:717-720 (http://www.gsajournals.org/gsaonline/?request=get- abstract&doi=10.1130%2FG19663.1). Read the original article at http://www.astrobio.net/news/article596.html. An additional article on this subject is available at http://www.spacedaily.com/news/mars-life-03g.html. ________________________________________________________________________ FIRST SUPERNOVAE QUICKLY SEEDED UNIVERSE WITH STUFF OF LIFE Harvard-Smithsonian Center for Astrophysics release 03-21 18 September 2003 The early universe was a barren wasteland of hydrogen, helium, and a touch of lithium, containing none of the elements necessary for life as we know it. From those primordial gases were born giant stars 200 times as massive as the Sun, burning their fuel at such a prodigious rate that they lived for only about 3 million years before exploding. Those explosions spewed elements like carbon, oxygen and iron into the void at tremendous speeds. New simulations by astrophysicists Volker Bromm (Harvard-Smithsonian Center for Astrophysics), Naoki Yoshida (National Astronomical Observatory of Japan) and Lars Hernquist (CfA) show that the first, "greatest generation" of stars spread incredible amounts of such heavy elements across thousands of light-years of space, thereby seeding the cosmos with the stuff of life. This research is posted online at http://arxiv.org/abs/astro-ph/0305333 and will be published in an upcoming issue of The Astrophysical Journal Letters. "We were surprised by how violent the first supernova explosions were," says Bromm. "A universe that was in a pristine state of tranquility was rapidly and irreversibly transformed by a colossal input of energy and heavy elements, setting the stage for the long cosmic evolution that eventually led to life and intelligent beings like us." Approximately 200 million years after the Big Bang, the universe underwent a dramatic burst of star formation. Those first stars were massive and fast-burning, quickly fusing their hydrogen fuel into heavier elements like carbon and oxygen. Nearing the end of their lives, desperate for energy, those stars burned carbon and oxygen to form heavier and heavier elements until reaching the end of the line with iron. Since iron cannot be fused to create energy, the first stars then exploded as supernovae, blasting the elements that they had formed into space. Each of those first giant stars converted about half of its mass into heavy elements, much of it iron. As a result, each supernova hurled up to 100 solar masses of iron into the interstellar medium. The death throes of each star added to the interstellar bounty. Hence, by the remarkably young age of 275 million years, the universe was substantially seeded with metals. That seeding process was aided by the structure of the infant universe, where small protogalaxies less than one-millionth the mass of the Milky Way crammed together like people on a crowded subway car. The small sizes of and distances between those protogalaxies allowed an individual supernova to rapidly seed a significant volume of space. Supercomputer simulations by Bromm, Yoshida, and Hernquist showed that the most energetic supernova explosions sent out shock waves that flung heavy elements up to 3,000 light-years away. Those shock waves swept huge amounts of gas into intergalactic space, leaving behind hot "bubbles," and triggered new rounds of star formation. Supernova expert Robert Kirshner (CfA) says, "Today this is a fascinating theory, based on our best understanding of how the first stars worked. In a few years, when we build the James Webb Space Telescope, the successor to the Hubble Space Telescope, we should be able to see these first supernovae and test Volker's ideas. Stay tuned!" Lars Hernquist notes that the second generation of stars contained heavy elements from the first generation--seeds from which rocky planets like Earth could grow. "Without that first, 'greatest generation' of stars, our world would not exist." Headquartered in Cambridge, MA, the Harvard-Smithsonian Center for Astrophysics is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe. Animations and an image are available at http://cfa- www.harvard.edu/press/pr0321image.html. Contacts: David Aguilar, Director of Public Affairs Harvard-Smithsonian Center for Astrophysics Phone: 617-495-7462 Fax: 617-495-7468 E-mail: daguilar@cfa.harvard.edu Christine Lafon, Public Affairs Specialist Harvard-Smithsonian Center for Astrophysics Phone: 617-495-7463 Fax: 617-495-7016 E-mail: clafon@cfa.harvard.edu Additional articles on this subject are available at: http://www.space.com/scienceastronomy/greatest_explosions_030918.html http://www.spacedaily.com/news/supernova-03i.html http://spaceflightnow.com/news/n0309/18supernovae/ http://www.universetoday.com/am/publish/early_universe_supernovae.html ________________________________________________________________________ WHY SHOULD WE GO THERE--NEW CONTEST! By Maggie Zubrin Mars Society release 21 September 2003 Mars Society members consist of engineers, microbiologists, rocket scientists and other key players who are helping to shape the technologies that will enable us to get to Mars, explore the planet and possibly one day settle there. But the Mars Society is more than a technical society. Our members also include writers, anthropologists, philosophers and activists who believe that setting a positive course for the future of humanity begins now, with us. One of the hardest parts of convincing the "person on the street" and therefore the voters, and thence the politicians, is explaining why sending humans to Mars is so critical to our vision of a positive future. The reasons we adopt are as varied as our political, religious and philosophical viewpoints and are usually as well thought out as they are highly personal. It is time to emphasize the importance of why, not just how or when or how much money. The Why Mars Contest Entries are accepted from all Mars Society members and others interested in sending humans to Mars. Entries should be in essay form, advocating a humans to Mars program, and explaining the importance (the why) of such a program. Entries should be one to five pages in length, typewritten and submitted electronically. Separate winners will be chosen from the following categories: Regular Mars Society Members Non-Members Youth to age eighteen Senior Mars Society Members Alternative media (poetry, short story, song, etc.) Winners will receive a variety of prizes, including books, discounted conference admission, free membership, etc. All acceptable entries will be edited for publication in a collection of essays, either on CD or in book form. Please submit your entry to MSWhyMars@aol.com, either as embedded text or as a clearly labeled attachment. I look forward to hearing your ideas. The deadline for primary submissions is November 15, 2003. Winners of prizes will be decided at that time and we will include a few submissions in our hard copy bulletin, The Homeworld Journal. We will have a secondary deadline to allow for editorial polishing prior to the final publication. That deadline has not yet been determined. ________________________________________________________________________ EARLY MARS WAS FROZEN BUT HABITABLE, PART II From Astrobiology Magazine 22 September 2003 Early Mars was cold--very cold, says Chris McKay, a planetary scientist at the NASA Ames Research Center. But that doesn't mean it was incapable of supporting life. McKay has extensively studied life in some of the harshest environments in the world: the Antarctic dry valleys, the Arctic, and the Atacama desert. At a meeting of the American Astronomical Society's Division of Planetary Sciences, held in September 2003 in Monterey, CA, McKay gave a plenary talk in which he discussed the evidence for a cold, but wet, early Mars. McKay compared these early martina conditions to Antarctica's modern-day dry valleys. And he laid out a strategy for searching for evidence of the organisms that may have inhabited Mars during its first billion years. His talk is presented here in two parts; this is part two. As I mentioned earlier, Antarctica is very cold, but the pressure is high enough to support liquid. So when the glaciers melt, the water flows down the Onyx River, and it's stable against boiling and it flows into the lake. That's the one requirement that's not met on Mars today. The reason that you couldn't see such systems on Mars today is not because it's too cold. Cold isn't really the issue here. It's because the pressure is too low. So the key environmental factor for making Mars a better place for life, a kinder, gentler planet, is not making it warmer. The key factor is raising the pressure up from 6 to maybe 100 millibar. [One hundred millibar is one-tenth of the pressure on Earth at sea level.] Not much higher than that would be needed. At that pressure, liquid water could exist on a very cold Mars. Lake Vanda in Antarctica could be an analog, for example, for Gusev Crater, which Nathalie Cabrol and many others have shown is likely once to have been full of water. If you look around at the terrain around Gusev, you can see that it would have been very cold at the time. So the remnant of an ice-covered lake could be what the MER-A lander "Spirit" is going to land in. And what might it find? Probably the best thing it might find in a place like this is a fossil. And now I want to go back to the question that I raised originally. Why are we going to Mars? We're going to Mars to search for a second genesis of life. A second genesis of life is not something we're going to get from a fossil. Fossils are not enough. We'd be happy to find a good fossil on Mars. I'm sure it would make the cover of Science, or Nature, depending on whether it's NASA or ESA that finds it. It would tell us that there was life on Mars. But it wouldn't tell us the nature of that life, or its relationship, if any, to life on Earth. That's the key question. We want to know not just was there life on Mars, but how does it relate to us? Are martian organisms our cousins, or do they represent a second genesis? Well, to do that, again I return to analogs on Earth, as a way of developing a strategy for searching for a second genesis on Mars. In Siberia, in old permafrost on Earth, we find frozen bacteria. This is 3.5-million-year-old permafrost, some of the oldest permafrost on Earth. And we find viable bacteria in this permafrost. We're developing drills that can drill in permafrost without drilling fluid. There was some work done just a few months ago up in the Arctic, drilling in permafrost with air-supported drills, using a technique that lets us demonstrate that there's no contamination getting into the drill cores. We're learning how to use a drill as a microbiological instrument. In Antarctica, we think we have ice that may be 8 million years old. Again, in that ice, we find viable bacteria. In the oldest and coldest ice on Earth, we find organisms still preserved. So we want to apply this logic to Mars. Could something remain preserved in the permafrost on Mars for a long period of time, perhaps billions of years? Well, what limits long-term dormancy? There are two factors. One is the second law of thermodynamics, thermal decay. But this is not that important on Mars because it is so cold there. The other, background radiation, from natural levels of the decay of uranium, thorium and potassium, even deep below the surface, is about 0.2 rads per year on Earth and would be roughly similar on Mars. This would deliver a lethal dose, even to the most radiation-resistant organisms, in about 100 million years. So although it's cold enough in the martian permafrost for life to be preserved, over the time period that we're interested, in there would be hundreds of lethal doses delivered to any dormant organisms trapped there. So "It's dead, Jim." But it's there. And that's important. Because there's a big difference between something that's dead and a fossil. If you're searching for life and you find a corpse--that's what it would be, a corpse--you can do an autopsy. You can determine whether the corpse has the same genetic biological content that we have. You can't do an autopsy on a fossil. And the permafrost on Mars is where we have the best chance of finding these frozen, dead micro-martian corpses to do an autopsy on. We have thought for awhile that there was a permafrost on Mars, that it had deep, cold ice-cemented ground. Now we have further indications that that's the case. The Mars Odyssey neutron spectrometer results show ground ice in the polar regions, and the magnetometer results indicate that in some of those regions, the ice is very old and very stable. So I would argue that at longitude 180 degrees west and latitude about 80 south, far enough south that you're in deep permafrost but not so far south that you're in the younger polar deposits, you could find the oldest frozen material on Mars. And the magnetic striping in the terrain there, seen by the magnetometer onboard Mars Global Surveyor, confirm that this is a region that's likely to have been undisturbed by impacts for billions of years. Because you see where there have been large impacts, like in Hellas and Argyre Basins, that the pattern of magnetic striping has been erased. So one strategy for searching for life is to go find fossils in Gusev. But then we also need to address the question of a second genesis, which is really the big question, the question that scientifically and culturally drives astrobiology. And to do that, we need to go drill deep into this permafrost where we will hopefully find an actual martina organism. Now, if we find a dead organism on Mars, how are we going to tell if it was once alive? How are we going to recognize life? One is to use a tricorder. You remember in episode 26, they adjusted the tricorder so they could not just detect life, but could detect silicon life, all done within a few seconds of the show--a great device. Another approach for detecting life is to say, "Well, we'll just know it when we see it." But maybe we can do better. And I want to make the suggestion that there's a general principle that we can use to detect life. I call it the LEGO principle. And it's based on the rather simple observation that life is built largely from a small number of components. Life is not just a hodge-podge of stuff all thrown together. It's certain bricks, used over and over again. The basic polymers of life, the proteins, the polysaccharides, the nucleotides, DNA and RNA, are all based on these few bricks, used over and over again. The same way a LEGO city is built out of identical bricks. And this is likely a common property of biology, as well as of mass-produced children's toys, throughout the universe. There are, for example, the 20 amino acids that are used as the LEGO blocks in building up the proteins used by on Earth. Alien organisms might have a different set of LEGO blocks, but they would have a set of LEGO blocks. They would use certain molecules over and over again. And we would see these molecules show up in unusually high numbers. And that's, I argue, a possible way to recognize a biological organic material from a non-biological one, even if it's alien and we can't amplify it with PCR. So I'd like to propose that on a future mission to Mars we send a 10-meter drill to the polar regions, to the permafrost, to look for martian LEGO blocks. I think that's where we have the best chance of digging up some ancient organic material from martian bugs, and of finding evidence of a second genesis of life. Read the original article at http://www.astrobio.net/news/article601.html. ________________________________________________________________________ SCIENTISTS PRACTICE MARS DRILLING NEAR ACIDIC SPANISH RIVER NASA/ARC release 03-74AR 22 September 2003 To develop techniques to drill into the surface of Mars to look for signs of life, NASA and Spanish scientists recently began drilling 150 meters (495 feet) into the ground near the source of the waters of the Rio Tinto, a river in southwestern Spain, part of a three-year effort that will include the search for underground life forms. During the Mars Analog Research and Technology Experiment (MARTE), scientists and engineers from NASA, U.S. universities and the Spanish Centro De Astrobiología (Center for Astrobiology) hope to show how robot systems could look for life below Mars' surface. Scientists believe that liquid water may exist deep underground on Mars. "The Rio Tinto area is an important analog to searching for life in liquid water, deep beneath the subsurface of Mars," said Carol Stoker, principal investigator of the three-year project and a scientist at NASA Ames Research Center in California's Silicon Valley. Scientists say bacteria that are present in the very acidic Rio Tinto play a role in producing acid in the river, a byproduct of the metabolism of iron and sulfur minerals in the region. The Rio Tinto looks like deep red wine, because iron is dissolved in the highly acidic river water. Scientists hope to find similar bacteria deep underground at the Rio Tinto, where groundwater interacts with iron and sulfur minerals. These underground bacteria may subsist on chemicals and minerals under the surface, according to scientists. The drilling is expected to yield samples that experts will analyze to gain knowledge about subsurface life forms at the site. Eventually, scientists will use this 'ground truth' information to check the accuracy of later robotic efforts to identify life forms, organic compounds and minerals. In later phases of the experiment, scientists at NASA facilities in the United States and at the Centro de Astrobiología in Madrid will remotely operate a robotic drill and life-detection instruments, and will interpret the results, all via satellite, to simulate a mission to search for life on Mars. The subsurface is the key environment for searching for life on other planets, according to MARTE scientists. "Life needs liquid water and a source of energy," Stoker said. "On Earth, most common life forms are at the surface where sunlight provides the energy, but liquid water occurs rarely at the martian surface, if at all. Liquid water is expected in the subsurface of Mars. So NASA plans to use robotic drilling to search for subsurface life. That is why we are testing the life-search strategy in the Rio Tinto, where subsurface water and chemical energy are expected to support life." Stoker added. Scientists say evidence suggests the chemistry of the Rio Tinto and its biology may be the result of an underground biologically based chemical reactor fueled by organisms that do not need oxygen gas to survive. MARTE scientists believe such a system may exist in the subsurface of the Rio Tinto area, according to Ricardo Amils Pibernat, a biologist at the Centro de Astrobiología and a specialist on the biology of the Rio Tinto. If found, this type of life would represent an entirely new subsurface life system, he said. "In addition to looking for evidence of subsurface life, we hope MARTE inspires students to pursue careers in science and engineering," Stoker said. A series of eight one-hour educational webcasts about MARTE will take place beginning on September 29 and continue through October 15. The webcasts and their schedule are accessible at this Internet URLs, http://robotics.nasa.gov/courses/fall2003 and http://www.cab.inta.es. The Astrobiology Science and Technology for Exploring Planets program at NASA Headquarters, Washington, is funding the project. The Spanish contribution to the project is supported by the Ministerio de Ciencia y Tecnologia, Comunidad de Madrid and the Instituto Nacional de Tecnica Aeroespacial (Ministerio de Defensa). An audio companion to this article is available at http://amesnews.arc.nasa.gov/audio/tinto/tintoaudio.html. Contacts: John Bluck NASA Ames Research Center, Moffett Field, CA Phone: 650-604-5026 or 650-604-9000 E-mail: John.G.Bluck@nasa.gov Juan Bautista Rodriguez Instituto Nacional de Tecnica Aeroespacial (INTA), Spain Phone: 34 91 520 1938 An additional article on this subject is available at http://www.spacedaily.com/news/mars-driller-03a1.html. ________________________________________________________________________ NEW ADDITIONS TO THE ASTROBIOLOGY INDEX By David J. Thomas http://www.lyon.edu/projects/marsbugs/astrobiology/astrobiology.html 22 September 2003 Astrobiology and planetary engineering articles http://www.lyon.edu/projects/marsbugs/astrobiology/online_articles1.html Agence France-Presse, 2003. NASA's Galileo space probe disintegrates over Jupiter. SpaceDaily. Astrobiology Magazine, 2003. Galileo joins Jupiter, literally. Astrobiology Magazine. P. Bond, 2003. Galileo spacecraft crashes into Jupiter. Spaceflight Now. L. David, 2003. Journey's end: last gasp for Galileo. Space.com. C. P. McKay, 2003. Early Mars was frozen but habitable, part II. Astrobiology Magazine. L. Mullen, 2003. Chomping on nano-nuggets. Astrobiology Magazine. NASA Jet Propulsion Laboratory, 2003. Galileo plunges into Jupiter. Universe Today. C. Phillips, 2003. Farewell to Galileo. Space.com. Terrestrial extreme environments articles http://www.lyon.edu/projects/marsbugs/astrobiology/online_articles2.html NASA Ames Research Center, 2003. Scientists practice mars drilling near acidic Spanish river. SpaceDaily. Human space exploration articles http://www.lyon.edu/projects/marsbugs/astrobiology/online_articles3.html Agence France-Presse, 2003. First Chinese manned space flight within three months. SpaceDaily. H. Yi, 2003. China to launch first astronauts after National Day. SpaceDaily. Evolution (biological, chemical and cosmological) articles http://www.lyon.edu/projects/marsbugs/astrobiology/online_articles5.html R. R. Britt, 2003. The greatest explosions studies reveal crowded, violent early universe. Space.com. L. R. Doyle, 2003. Planetary primer: Mars and Venus. Astrobiology Magazine. Harvard-Smithsonian Center for Astrophysics, 2003. Early supernovae seeded the universe with elements. Universe Today. Harvard-Smithsonian Center for Astrophysics, 2003. First supernovae quickly seeded universe with stuff of life. SpaceDaily. Harvard-Smithsonian Center for Astrophysics, 2003. First supernovae seeded universe with stuff of life. Spaceflight Now. University of Sydney, 2003. Red giant spotted swallowing its planets. Universe Today. Astrobiology and extreme environments book list http://www.lyon.edu/projects/marsbugs/astrobiology/astrobiology_books.ht ml D. Grinspoon, 2003. Lonely Planets: The Natural Philosophy of Alien Life. Harper Collins. ________________________________________________________________________ CASSINI SIGNIFICANT EVENTS NASA/JPL release 11-17 September 2003 The most recent spacecraft telemetry was acquired from the Madrid tracking station on Wednesday, September 17. 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. On-board activities this week included uplink of a Magnetospheric Imaging Instrument flight software mini sequence and flight software checkout, a Radio Science Subsystem (RSS) Ultrastable Oscillator test, RSS Periodic Instrument Maintenance, boresight calibration, pattern calibration, and quiet test, and a probe checkout. Delivery Coordination Meetings were held for E-Kernel generation software, Mission Sequence Subsystem D9.1.1, and the electronic command request form V1.0. Official port 2 delivery was completed as part of the Science Operations Plan implementation process for tour sequences S01, S02, S03, and S04. A kickoff meeting was held for the Science Planning Team process for cruise sequence C43. 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. ________________________________________________________________________ THE FINAL DAY ON GALILEO NASA/JPL release 19 September 2003 The wind-up Well, after twelve years of pre-launch development and planning, six years of interplanetary cruise, and nearly eight years in orbit, our exciting, quarter-century odyssey has finally come down to this: the final 19 hours of existence for the Galileo spacecraft. It began life in October 1977 as the Jupiter Orbiter Probe mission, was launched in October 1989, and arrived at Jupiter in December 1995. After circling the solar system's largest planet 35 times, it is about to plunge into the atmosphere of Jupiter, becoming only the second man-made object to do so, following the smaller Galileo atmospheric probe that accompanied the Orbiter to Jupiter. From launch to impact, the stalwart spacecraft has traveled 4,631,778,000 kilometers (2,878,053,500 miles) on 925 kilograms of propellant (246 gallons), not counting the fuel for the shuttle. In all that time, and across all those miles, Galileo has returned over 30 gigabytes of data, including 14,000 pictures. One chapter of the volumes of scientific data produced by Galileo over the years includes the discovery of likely sub-surface water oceans on the icy satellite Europa. This has fueled speculation about the possibility of life existing in that environment, and is prompting plans for future spacecraft to return to Europa to search for life. Since the Galileo spacecraft was never designed to specifically search for life, it was never subjected to the rigorous sterilization procedures such as those mandated for craft going to Mars. To prevent any possible future biological contamination of Europa, the decision was made to provide a final resting place for the Galileo Orbiter that guarantees the spacecraft will never collide with any of the Jovian moons. That resting place is Jupiter itself. The pitch The final day for Galileo begins on Saturday evening at 5:52 PM PDT [see Note 1], when the spacecraft is just over 18 Jupiter radii (1.32 million kilometers or 822,000 miles) from the center of the planet, and closing fast. At that time, the instruments that measure the magnetic and electric fields and the particle environment stop collecting data for a while. These instruments are the Dust Detector Subsystem (DDS), the Energetic Particle Detector (EPD), the Heavy Ion Counter (HIC), the Magnetometer (MAG), and the Plasma and Plasma Wave Subsystems (PLS and PWS). They have been collecting data continuously for the past six months, storing these data in a computer memory buffer for later transmission to Earth. By stopping this collection for 7 hours, this buffer is allowed to drain, and subsequent data collected can be transmitted to Earth almost immediately. At 10:52 PM the spacecraft attitude control system is told to base its orientation calculations on the observations of a single star. Normally, three stars are used, but in the intense radiation environment near Jupiter, noise in the star sensor circuits overwhelms the signals from fainter stars, and a single, bright star is selected which can rise above the noise and still be detected. Today that star is Vega (Alpha Lyrae), the fourth brightest star in the sky. At 12:52 AM Sunday, the 70-meter-diameter (230 feet) Deep Space Network tracking station antenna near Madrid, Spain, is listening to the spacecraft. The science instruments are configured properly, and begin again to send their data in real-time to Earth. Galileo has closed the distance to 13.5 Jupiter radii (965,000 kilometers or 600,000 miles). At 5:55 AM, the tracking antenna at Goldstone in the Southern California desert joins the Madrid station, and for the next three hours both stations are collecting the faint signals sent from a half a billion miles out in the solar system. At 6:07 AM, the distance has closed to 10 Jupiter radii (715,000 kilometers or 444,000 miles) and MAG changes the sensitivity of its measurements in anticipation of the stronger magnetic fields to come. At 6:24 AM, all instruments except MAG stop collecting data for just over an hour. During this time the data collection rate on the spacecraft is greater than the rate the ground stations can reliably receive. If the collection continued, the data would accumulate in the storage buffer to such an extent that the buffer would not have a chance to empty before the spacecraft is lost from view. This brief pause allows the most valuable data collected nearest to Jupiter to be sent without buffering. At 7:22 AM the radio signal sent from the spacecraft is changed to provide more power to the underlying carrier signal. This will help the ground stations keep track of the signal as Jupiter's increasing gravitational pull speeds the spacecraft up and alters the apparent transmission frequency, due to the familiar Doppler effect. The swing At 9:05 AM, Galileo crosses the volcanic satellite Io's orbit at a distance of 6 Jupiter radii (422,000 kilometers or 262,000 miles). The spacecraft has spent most of its 8-year travels around Jupiter outside of this distance, to keep the received radiation dose down. It has ventured significantly inside this distance only twice. Once, in December 1995, as Galileo first entered Jupiter orbit, when we reached 4 Jupiter radii (3 radii over the clouds), and again in November 2002, when a flyby of the small inner moon Amalthea took the craft down to 2 Jupiter radii (1 Jupiter radius, 71,500 kilometers or 44,400 miles over the cloud tops). This time, though, it's a one-way trip. The distance will only get shorter. By 9:42 AM, the intensity of the radiation noise has reached a point where even a bright star like Vega can no longer reliably be seen by the attitude control star scanner. The software is now told to expect to see no more stars, ever. At 11:31 AM, Galileo is two Jupiter radii above the clouds (143,000 kilometers or 89,000 miles) and the Magnetometer instrument has taken its final data for the mission. At this distance from Jupiter, the magnetic field is so strong that the instrument, even in its most robust configuration, would produce a signal that would be completely saturated, and of no further scientific value. Seventeen minutes later, at 11:48 AM, the spacecraft passes the orbit of the tiny satellite Amalthea, and at about 12:17 PM, passes the orbits of the innermost moons, Adrastea and Metis. Galileo is now just 57,500 kilometers (35,700 miles) above the clouds, closing fast, and picking up speed. As the spacecraft passes Amalthea a special measurement will be taken using the star scanner. During our previous flyby of this small body on November 5, 2002, flashes of light were seen by the star scanner that might indicate the presence of rocky debris circling Jupiter in the vicinity of the satellite. Though on this final pass, Galileo will not be near Amalthea, the measurement may help confirm or constrain the extent of this hypothesized orbital debris. At 12:26 PM the Galileo Orbiter joins the Galileo Probe in going closer to Jupiter than any other man-made object, passing the 1973 mark that Pioneer 11 set on its swing through the Jupiter system. At 43,000 kilometers altitude (26,725 miles), the spacecraft is now at a distance that is 1/9th of the span between Earth and its own Moon. This is also the approximate altitude that geosynchronous communications satellites orbit above the Earth's surface. What seems like a vast expanse when viewed in terms of the Earth seems like such a small step away when viewed in terms of Jupiter, which has a diameter that is 11 times that of Earth. At 12:42 PM with 7 minutes and 10 seconds to go, Galileo moves from day to night as it passes into Jupiter's shadow, and, one minute later, passes behind the limb of the giant planet as seen from Earth. Only 9,283 kilometers (5,768 miles) above the clouds, the path of the spacecraft now takes it out of sight of ground controllers, never to be seen again. The last data ever to be received from the Galileo spacecraft has now been sent. The remaining few minutes of the craft will be spent in darkness, and alone. The hit Finally, at 12:49:36 PM, Sunday, September 21, 2003, Galileo reaches the end of its nearly 14 year odyssey through space with a final, glorious meeting with the king of the solar system's planetary entourage. This event, though described as an impact, is actually the gradual, but very rapid, immersion in the gas giant's vast atmosphere. The time stated is when the spacecraft reaches that point in the atmosphere where the pressure reaches one bar, the equivalent of Earth's atmospheric pressure at sea level. For reference, this point is 71,492 kilometers (44,423 miles) from the center of the planet, at the point where Galileo enters. The entry point is approximately 1/4 degree south of Jupiter's equator. If there were observers floating along at the cloud tops, they could see Galileo streaming in from a point about 22 degrees above the local horizon. Streaming in could also be described as screaming in, as the speed of the craft relative to those observers would be 48.26 kilometers per second (nearly 108,000 miles per hour!). That is like traveling from Los Angeles to New York City in 82 seconds. In comparison, the Galileo atmospheric Probe, aerodynamically designed to slow down when entering, and parachute gently through the clouds, first reached the atmosphere at a slightly more modest 47.6 kilometers per second (106,500 miles per hour). The Galileo Orbiter, with the aerodynamic qualities of a brick, and no parachute, will not endure nearly as controlled and graceful a fate. It will rapidly burn up through friction with the atmosphere, returning to its constituent atoms as it makes its unnoticeable impact on the vast weather systems of Jupiter. In the life of the giant planet, Galileo will look like another speck of cosmic debris. It would not be nearly as observable as the fragments of Comet Shoemaker-Levy 9, which crashed into Jupiter's atmosphere in July 1994 and was observed by Galileo. In the life of the planet Earth, with its inhabitants, Galileo will live on in the memories of those who worked on the project, as well as those of new generations who study the astronomy textbooks, rewritten with the reams of data returned over the years. Nearly 393 years ago, Galileo Galilei first turned the newly developed telescope on Jupiter, and spied the four satellites that bear his name; lonely, silent sentinels that began to show proof that Earth was not the center of the universe. Mankind has since dreamed, and schemed, and developed robotic messengers to visit and study our ever more complex surroundings. What more fitting end to the messenger that is also Galileo's namesake, than to find final repose in Jupiter, while overhead circle those four sentinels, no longer lonely, no longer silent for we were there. We listened to what they had to say, and they spoke volumes. They have become part of our family, our circle of familiar friends. As with all good friendships, they have inspired us to do more, go farther, look closer and deeper, to learn. The future lies before us. Thank you for sharing our journey so far. Note 1. Pacific Daylight Time (PDT) is 7 hours behind Greenwich Mean Time (GMT). The time when an event occurs at the spacecraft is known as Spacecraft Event Time (SCET). The time at which radio signals reach Earth indicating that an event has occurred is known as Earth Received Time (ERT). On the day of impact, it takes Galileo's radio signals 52 minutes 18 seconds to travel between the spacecraft and Earth. All times quoted above are in Earth Received Time at JPL in Pasadena. To summarize, Galileo will impact Jupiter at: Spacecraft Event Time (SCET) Earth Receive Time (ERT) 11:57:18 PDT 12:49:36 PDT 18:57:18 GMT 19:49:36 GMT Additional articles on this subject are available at: http://www.spacedaily.com/news/galileo-03e.html http://www.spacedaily.com/news/galileo-03h.html http://spaceflightnow.com/galileo/030920preview.html http://spaceflightnow.com/galileo/030920eomsequence.html http://spaceflightnow.com/galileo/030920top10science.html ________________________________________________________________________ GALILEO--END OF MISSION By Ron Baalke NASA/JPL release 19 September 2003 On September 21, the Galileo mission will come to an end when the hardy spacecraft plunges into the crushing pressure of Jupiter's atmosphere. This planned maneuver will prevent the risk of Galileo drifting to an unwanted impact with the moon Europa, which may harbor a subsurface ocean. The following items are available at either of these URL's: http://www.jpl.nasa.gov/webcast/galileo/ http://galileo.jpl.nasa.gov Live End of Mission Webcast on September 21, 11:00 AM PDT (2:00 PM EDT) (RealPlayer required) Galileo Legacy at Jupiter Video (RealPlayer and Quicktime formats) Jupiter Impact Animations (MPEG and Quicktime formats) Archived Webcast of the Space Science Update held on September 17 (RealPlayer required) Archived Webcast of the Galileo lecture held on September 18 (RealPlayer required) Top 10 Galileo Science Images End of Mission Press Kit (PDF) Galileo Fact Sheet (PDF) Galileo End of Mission Coloring Book ________________________________________________________________________ GALILEO END OF MISSION STATUS NASA/JPL release 2003-129 21 September 2003 The Galileo spacecraft's 14-year odyssey came to an end on Sunday, September 21, when the spacecraft passed into Jupiter's shadow then disintegrated in the planet's dense atmosphere at 11:57 AM Pacific Daylight Time. The Deep Space Network tracking station in Goldstone, CA, received the last signal at 12:43:14 PDT. The delay is due to the time it takes for the signal to travel to Earth. Hundreds of former Galileo project members and their families were present at NASA's Jet Propulsion Laboratory in Pasadena, CA, for a celebration to bid the spacecraft goodbye. "We learned mind-boggling things. This mission was worth its weight in gold," said Dr. Claudia Alexander, Galileo project manager. Having traveled approximately 4.6 billion kilometers (about 2.8 billion miles), the hardy spacecraft endured more than four times the cumulative dose of harmful jovian radiation it was designed to withstand. During a previous flyby of the moon Amalthea in November 2002, flashes of light were seen by the star scanner that indicated the presence of rocky debris circling Jupiter in the vicinity of the small moon. Another measurement of this area was taken today during Galileo's final pass. Further analysis may help confirm or constrain the existence of a ring at Amalthea's orbit. "We haven't lost a spacecraft, we've gained a steppingstone into the future of space exploration," said Dr. Torrance Johnson, Galileo project scientist. The spacecraft was purposely put on a collision course with Jupiter because the onboard propellant was nearly depleted and to eliminate any chance of an unwanted impact between the spacecraft and Jupiter's moon Europa, which Galileo discovered is likely to have a subsurface ocean. Without propellant, the spacecraft would not be able to point its antenna toward Earth or adjust its trajectory, so controlling the spacecraft would no longer be possible. The possibility of life existing on Europa is so compelling and has raised so many unanswered questions that it is prompting plans for future spacecraft to return to the icy moon. Galileo was launched from the cargo bay of Space Shuttle Atlantis in 1989. The exciting list of discoveries started even before Galileo got a glimpse of Jupiter. As it crossed the asteroid belt in October 1991, Galileo snapped images of Gaspra, returning the first ever close-up image of an asteroid. Less then a year later, the spacecraft got up close to yet another asteroid, Ida, revealing it had its own little "moon," Dactyl, the first known moon of an asteroid. In 1994 the spacecraft made the only direct observation of a comet impacting a planet--comet Shoemaker-Levy 9's collision with Jupiter. The descent probe made the first in-place studies of the planet's clouds and winds, and it furthered scientists' understanding of how Jupiter evolved. The probe also made composition measurements designed to assess the degree of evolution of Jupiter compared to the Sun. Galileo made the first observation of ammonia clouds in another planet's atmosphere. It also observed numerous large thunderstorms on Jupiter many times larger than those on Earth, with lightning strikes up to 1,000 times more powerful than on Earth. It was the first spacecraft to dwell in a giant planet's magnetosphere long enough to identify its global structure and to investigate the dynamics of Jupiter's magnetic field. Galileo determined that Jupiter's ring system is formed by dust kicked up as interplanetary meteoroids smash into the planet's four small inner moons. Galileo data showed that Jupiter's outermost ring is actually two rings, one embedded within the other. Galileo extensively investigated the geologic diversity of Jupiter's four largest moons: Ganymede, Callisto, Io and Europa. Galileo found that Io's extensive volcanic activity is 100 times greater than that found on Earth. The moon Europa, Galileo unveiled, could be hiding a salty ocean up to 100 kilometers (62 miles) deep underneath its frozen surface--containing about twice as much water as all the Earth's oceans. Data also showed Ganymede and Callisto may have a liquid-saltwater layer. The biggest discovery surrounding Ganymede was the presence of a magnetic field. No other moon of any planet is known to have one. The prime mission ended six years ago, after two years of orbiting Jupiter. NASA extended the mission three times to continue taking advantage of Galileo's unique capabilities for accomplishing valuable science. The mission was possible because it drew its power from two long-lasting radioisotope thermoelectric generators provided by the Department of Energy. "The mission was a testimonial to the persistence of NASA even through tremendous challenges. It was a phenomenal mission," said Sean O'Keefe, NASA administrator. JPL, a division of the California Institute of Technology in Pasadena, manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL designed and built the Galileo orbiter, and operated the mission. Additional information about the Galileo mission and its discoveries is available online at: http://www.jpl.nasa.gov/galileo-legacy http://galileo.jpl.nasa.gov/ For information about NASA, visit http://www.nasa.gov. Contact: Carolina Martinez Jet Propulsion Laboratory, Pasadena, CA Phone: 818-354-9382 Additional articles on this subject are available at: http://www.astrobio.net/news/article600.html http://www.space.com/scienceastronomy/galileo_finale_030921.html http://www.spacedaily.com/2003/030921230441.zavyrggu.html http://spaceflightnow.com/galileo/030921galileogone.html http://www.universetoday.com/am/publish/galileo_plunges_jupiter.html ________________________________________________________________________ MARS GLOBAL SURVEYOR IMAGES NASA/JPL/MSSS release 11-17 September 2003 The following new images taken by the Mars Orbiter Camera (MOC) on the Mars Global Surveyor spacecraft are now available. Layers in Gale Crater (Released 11 September 2003) http://www.msss.com/mars_images/moc/2003/09/11/index.html First MOC Public Requested Image: Caldera of Pavonis Mons (Released 12 September 2003) http://www.msss.com/mars_images/moc/2003/09/12/index.html Ascraeus Mons Pits (Released 13 September 2003) http://www.msss.com/mars_images/moc/2003/09/13/index.html Kasei Valles Scene (Released 14 September 2003) http://www.msss.com/mars_images/moc/2003/09/14/index.html The Cydonia "D&M Pyramid" Landform (Released 15 September 2003) http://www.msss.com/mars_images/moc/2003/09/15/index.html Boulders on Phobos (Released 16 September 2003) http://www.msss.com/mars_images/moc/2003/09/16/index.html Landslide! (Released 17 September 2003) http://www.msss.com/mars_images/moc/2003/09/17/index.html All of the Mars Global Surveyor images are archived here 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. ________________________________________________________________________ MARS ODYSSEY THEMIS IMAGES NASA/JPL/ASU release 15-19 September 2003 Marching Dunes (Released 15 September 2003) http://themis.la.asu.edu/zoom-20030915a.html Nirgal Vallis (Released 16 September 2003) http://themis.la.asu.edu/zoom-20030916a.html Wind Streaks (Released 17 September 2003) http://themis.la.asu.edu/zoom-20030917a.html Cerberus Fossae (Released 18 September 2003) http://themis.la.asu.edu/zoom-20030918a.html Pavonis Mons Aureole (Released 19 September 2003) http://themis.la.asu.edu/zoom-20030919a.html All of the THEMIS images are archived at http://themis.la.asu.edu/latest.html. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, DC. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena. ________________________________________________________________________ STARDUST STATUS REPORT NASA/JPL release 19 September 2003 There was one Deep Space Network (DSN) tracking pass in the past week. Telemetry relayed from the spacecraft indicates it is healthy and all subsystems continue to operate normally. Information on the present position and orbits of the Stardust spacecraft and comet Wild 2 may be found on the "Where Is Stardust Right Now?" web page located at http://stardust.jpl.nasa.gov/mission/scnow.html. The implementation of Comet Wild 2 encounter sequence test cases has started in the Spacecraft Test Laboratory (STL). The test cases cover various fault protection scenarios. The Stardust Education and Public Outreach (E/PO) team participated in the NASA-wide Office Of Space Science Forum to coordinate NASA missions and NASA Center themes. The Stardust Principal Investigator, Don Brownlee, spoke to a group of 700 educators at the Challenger Space Center in Peoria, Arizona as part of the Smithsonian National Education and Museum Studies Program. 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 10, Number 38.