Marsbugs: The Electronic Astrobiology Newsletterweb.lyon.edu/projects/marsbugs/2004/20040225.pdf ·...

Marsbugs: The Electronic Astrobiology Newsletter Volume 11, Number 9, 24 February 2004 Editor/Publisher: David J. Thomas, Ph.D., Science Division, Lyon College, Batesville, Arkansas 72503-2317, USA. [email protected]

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. 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 INTELLIGENT DESIGN: THE NEW 'BIG TENT' FOR

EVOLUTION'S CRITICS By Terry Devitt

Page 2 CAN PEOPLE GO TO MARS?

By Tony Phillips Page 3 NASA'S NUCLEAR FOCUS AIMED AT 2009 MARS

LANDER By Brian Berger

Page 3 IS EUROPA CORROSIVE?

Based on New Scientist report Page 4 LIFE IN THE UNIVERSE TAKES ORDERS FROM SPACE

Arizona State University release Page 5 SEEKING NEW EARTHS? LOOK FOR DUST

Harvard-Smithsonian Center for Astrophysics release 04-08 Page 6 INNOVATIVE WEB SITE BRINGS MARS EXPLORATION

TO DESKTOPS NASA/JPL release 2004-067

Page 6 UNIVERSE HAS AT LEAST 30 BILLION YEARS LEFT

By Robert Roy Britt Page 7 NASA SELECTS 22 PROJECTS TO ADVANCE HUMAN

SUPPORT TECHNOLOGIES NASA release 04-066

Page 7 SDL RECEIVES CONTRACT TO RESEARCH PLANTS

FOR SPACE TRAVEL Space Dynamics Laboratory release

Page 7 MICROSCOPIC ASTRONAUTS

By Tony Phillips Page 8 STUDY MOVES IN ON WHY ASTRONAUTS SUFFER

BONE LOSS University of California—San Francisco release

Page 9 PLANETARY DEFENSE: PLANNING WITH PHANTOM ASTEROIDS By Leonard David

Page 9 ESA PREPARES FOR NEXT MISSIONS TO MARS

ESA release Page 10 GREENHOUSES FOR MARS

By Karen Miller Page 11 EARTH AT RISK: NEW CALLS FOR PLANETARY

DEFENSE By Leonard David

Announcements Page 11 NEW ADDITIONS TO THE ASTROBIOLOGY INDEX

By David J. Thomas Mission Reports Page 11 CASSINI SIGNIFICANT EVENTS

NASA/JPL release Page 12 MARS EXPLORATION ROVER UPDATES

NASA/JPL releases Page 18 MARS EXPRESS UPDATES

ESA releases Page 19 MARS GLOBAL SURVEYOR IMAGES

NASA/JPL/MSSS release Page 20 MARS ODYSSEY THEMIS IMAGES

NASA/JPL/ASU release Page 20 ROSETTA UPDATES

ESA and NASA releases Page 22 STARDUST STATUS REPORT

NASA/JPL release

INTELLIGENT DESIGN: THE NEW 'BIG TENT' FOR EVOLUTION'S CRITICS By Terry Devitt University of Wisconsin—Madison release 16 February 2004 Since the advent of Darwinism in the mid-19th century, a variety of movements have jousted for the intellectual high ground in the epic evolution versus creationism debate. At one end of the spectrum reside the "naturalistic evolutionists" who argue that life neither requires nor benefits from a divine creator. At the other pole, "scientific creationists" compress the entire history of the cosmos into 6,000 years and insist that the heavens and Earth and all life arose in one six-day creation event. Somewhere in the middle, are "theistic evolutionists" who argue for a creator, but see no reason why God could not have made the world by means of evolution.

And in the last decade or so, yet another movement has forged a claim in the high-stakes contest for intellectual primacy in the apparently ceaseless battle over the origins of life. The newest combatants, known as "intelligent-design theorists," reject both theistic and naturalistic evolution and, instead, claim evidence of the hand of an unknown "intelligent designer" in the genesis of life. But for Ron Numbers, the leading historian of the struggle between Darwinism and the anti-evolution movements of the past 140 years, intelligent design is simply the latest effort to create a "big tent for all people critical of evolution." As he views it, there are significant differences between scientific creationism and intelligent design. First, adherents of intelligent design scrupulously avoid biblical arguments to undermine evolutionary theory and argue instead that the subcellular complexity of life demands a knowing designer. What's more, many who subscribe to intelligent design have no problem accepting the great antiquity of life on Earth.

Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 9, 25 February 2004 2

"They do create some problems for people (strict creationists) who take the Bible seriously," says Numbers, a professor of history of science and medicine at UW-Madison. "They argue that the emphasis of young Earth creationists has been divisive." But those big differences notwithstanding, the intelligent design movement, like the more biblically oriented creationist movements, has the same ambitious agenda: to influence how science is taught in the nation's schools. In particular, they seek to weaken or eliminate the teaching of evolution—the dominant, unifying theory of modern biology—in public schools. Despite friction between the two camps, strict creationists and intelligent design adherents have at times joined forces to advance their educational agenda, the most recent example in Georgia, where a proposal for middle and high school science classrooms calls for deemphasizing evolution. Addressing scientists February 14, at the annual meeting of the American Association for the Advancement of Science (AAAS), Numbers gave historical context to the intelligent design movement, a movement that comes from no particular religious point of view, but nonetheless argues for a supernatural hand in the creation of life. "They couldn't care less about Genesis, and it is big enough that it can even appeal to some Jews and Muslims," says Numbers. "Its appeal is the complex nature of the world." At the root of intelligent design theory is that life, at its most basic biochemical level, is too complex to understand. That science has not unraveled many of the biochemical secrets of life is evidence that an "intelligent designer" has intervened, its theorists assert. This argument, says Numbers, ups the antievolution ante by arguing that science itself must change to accommodate the things it cannot explain. "They are claiming this is a scientific discovery, so it should be taught with other scientific claims in the schools," Numbers explains. "They are saying science should change its most fundamental rule, that science admits only naturalistic explanations." "The intelligent design people are saying that if the goal of science is to discover the truth, why should scientists, a priori, reject the theory of intelligent design? There must be intelligent design in the face of irreducible complexity." "They have made a tremendous splash," says Numbers. "They want to change the way science is done, but so far as I know, there has yet to appear an article in a scientific journal that makes this broader claim." The odds that the intelligent design movement—even with some scientist subscribers—will change the way science is done are slim, Number asserts. "To change science, they'll need to convince the scientific community, and they don't have a snowball's chance in hell of doing that." But the likelihood that intelligent design theory will make inroads into the public science classroom and into textbooks is good, Numbers believes. "It is very likely to influence science teaching. Intelligent design doesn't talk about God explicitly, so in some cases it might pass legal muster. They're trying to get into the schools that way, and they may be successful, I think." Scientists and other proponents of evolution, tend to conflate creationism and intelligent design. "They see intelligent design as little more than gussied up creationism, despite the significant differences," Numbers says. Either way, the stakes in the classroom are too high, he argues, to ignore the intellectual arguments of intelligent design as an answer to evolution. Read the original news release at http://www.news.wisc.edu/9450.html. An additional article on this subject is available at http://www.spacedaily.com/news/life-04p.html.

CAN PEOPLE GO TO MARS? By Tony Phillips From NASA Science News 17 February 2004 NASA has a mystery to solve. Can people go to Mars, or not? "It's a question of radiation," says Frank Cucinotta of NASA's Space Radiation Health Project at the Johnson Space Center. "We know how much radiation is out there, waiting for us between Earth and Mars, but we're not sure how the human body is going to react to it."

"Distant Shores." NASA artwork by Pat Rawlings/SAIC.

NASA astronauts have been in space, off and on, for 45 years. Except for a few quick trips to the moon, though, they've never spent much time far from Earth. Deep space is filled with protons from solar flares, gamma rays from newborn black holes, and cosmic rays from exploding stars. A long voyage to Mars, with no big planet nearby to block or deflect that radiation, is going to be a new adventure. NASA weighs radiation danger in units of cancer risk. A healthy 40-year-old non-smoking American male stands a (whopping) 20% chance of eventually dying from cancer. That's if he stays on Earth. If he travels to Mars, the risk goes up. The question is, how much? "We're not sure," says Cucinotta. According to a 2001 study of people exposed to large doses of radiation—e.g., Hiroshima atomic bomb survivors and, ironically, cancer patients who have undergone radiation therapy—the added risk of a 1000-day Mars mission lies somewhere between 1% and 19%. "The most likely answer is 3.4%," says Cucinotta, "but the error bars are wide." The odds are even worse for women, he adds. "Because of breasts and ovaries, the risk to female astronauts is nearly double the risk to males."

An artist's concept of DNA battered by galactic cosmic rays. Image credit: OBPR.


Researchers who did the study assumed the Mars-ship would be built "mostly of aluminum, like an old Apollo command module," says Cucinotta. The spaceship's skin would absorb about half the radiation hitting it. "If the extra risk is only a few percent, we're OK. We could build a spaceship using aluminum and head for Mars." (Aluminum is a favorite material for spaceship construction, because it's lightweight, strong, and familiar to engineers from long decades of use in the aerospace industry.) "But if it's 19%, our 40-something astronaut would face a 20% + 19% = 39% chance of developing life-ending cancer after he returns to Earth. That's not acceptable." The error bars are large, says Cucinotta, for good reason. Space radiation is a unique mix of gamma-rays, high-energy protons and cosmic rays. Atomic bomb blasts and cancer treatments, the basis of many studies, are no substitute for the "real thing." The greatest threat to astronauts en route to Mars is galactic cosmic rays—or "GCRs" for short. These are particles accelerated to almost light speed by distant supernova explosions. The most dangerous GCRs are heavy ionized nuclei such as 26Fe+. "They're much more energetic (millions of MeV) than typical protons accelerated by solar flares (tens to hundreds of MeV)," notes Cucinotta. GCRs barrel through the skin of spaceships and people like tiny cannon balls, breaking the strands of DNA molecules, damaging genes and killing cells.

Apollo command modules were well-enough shielded for quick trips to the Moon and back. Image credit: NASA. Astronauts have rarely experienced a full dose of these deep space GCRs. Consider the International Space Station (ISS): it orbits only 400 km above Earth's surface. The body of our planet, looming large, intercepts about one-third of GCRs before they reach the ISS. Another third is deflected by Earth's magnetic field. Space shuttle astronauts enjoy similar reductions. Apollo astronauts traveling to the moon absorbed higher doses—about 3 times the ISS level—but only for a few days during the Earth-moon cruise. GCRs may have damaged their eyes, notes Cucinotta. On the way to the moon, Apollo crews reported seeing cosmic ray flashes in their retinas, and now, many years later, some of them have developed cataracts. Otherwise they don't seem to have suffered much. "A few days 'out there' is probably safe," concludes Cucinotta.

But astronauts traveling to Mars will be "out there" for a year or more. "We can't yet estimate, reliably, what cosmic rays will do to us when we're exposed for so long," he says. Finding out is the mission of NASA's new Space Radiation Laboratory (NSRL), located at the US Department of Energy's Brookhaven National Laboratory in New York. It opened in October 2003. "At the NSRL we have particle accelerators that can simulate cosmic rays," explains Cucinotta. Researchers expose mammalian cells and tissues to the particle beams, and then scrutinize the damage. "The goal is to reduce the uncertainty in our risk estimates to only a few percent by the year 2015." Once the risks are known, NASA can decide what kind of spaceship to build. It's possible that ordinary building materials like aluminum are good enough. If not, "we've already identified some alternatives," he says. How about a spaceship made of plastic? "Plastics are rich in hydrogen—an element that does a good job absorbing cosmic rays," explains Cucinotta. For instance, polyethylene, the same material garbage bags are made of, absorbs 20% more cosmic rays than aluminum. A form of reinforced polyethylene developed at the Marshall Space Flight Center is 10 times stronger than aluminum, and lighter, too. This could become a material of choice for spaceship building, if it can be made cheaply enough. "Even if we don't build the whole spacecraft from plastic," notes Cucinotta, "we could still use it to shield key areas like crew quarters." Indeed, this is already done onboard the ISS. If plastic isn't good enough then pure hydrogen might be required. Pound for pound, liquid hydrogen blocks cosmic rays 2.5 times better than aluminum does. Some advanced spacecraft designs call for big tanks of liquid hydrogen fuel, so "we could protect the crew from radiation by wrapping the fuel tank around their living space," speculates Cucinotta. Can people go to Mars? Cucinotta believes so. But first, "we've got to figure out how much radiation our bodies can handle and what kind of spaceship we need to build." In labs around the country, the work has already begun. Read the original article at http://science.nasa.gov/headlines/y2004/17feb_radiation.htm. NASA'S NUCLEAR FOCUS AIMED AT 2009 MARS LANDER By Brian Berger From Space.com 18 February 2004 NASA's nuclear future promises more maneuverable, longer-lasting spacecraft and rovers with more onboard power than scientists know what to do with. Nuclear propulsion and power systems also could greatly reduce travel times to distant planets and supply energy to future planetary settlements, said Al Newhouse, director of NASA's Project Prometheus nuclear power and propulsion program. In the near term, Newhouse said, NASA's nuclear ambitions are focused on building a better battery for an unmanned lander launching to Mars in 2009 and a nuclear-electric propulsion system for a planned 2015 robotic tour of Jupiter's icy moons. NASA plans to spend more than $480 million in 2005 to continue work begun last year on a new generation of radioisotope power generators as well as nuclear-electric propulsion systems capable of producing thrust over long periods of time. Read the full article at http://www.space.com/businesstechnology/technology/nuclear_focus_040218-1.html. IS EUROPA CORROSIVE? Based on New Scientist report From Astrobiology Magazine 19 February 2004 Far from being a haven of ice and water and an ideal spot for the search for alien life, Jupiter's moon Europa may be a corrosive hotbed of acid and peroxide. That is the conclusion of researchers who met last week to prepare


for NASA's proposed Jupiter Icy Moons Orbiter, an ambitious mission to study Jupiter's moons. Almost all the information we have about Europa comes from the spacecraft Galileo, which completed its mission to study Jupiter and its moons close up before NASA dramatically crashed it into Jupiter last year. Although the general perception of Europa is of a frozen crust of water ice harboring a salty subterranean ocean kilometers below, researchers studying the most recent measurements say light reflected from the moon's icy surface bears the spectral fingerprints of hydrogen peroxide and strong acids, perhaps close to pH 0, if liquid. But they are not sure whether this is just a thin surface dusting or whether the chemicals come from the ocean below. The hydrogen peroxide certainly seems to be confined to the surface, as it is formed when charged particles trapped in Jupiter's magnetosphere strike water molecules on Europa. But parts of the surface are rich in water ice containing what looks like an acidic compound. Robert Carlson of NASA's Jet Propulsion Laboratory in Pasadena, California, thinks this is sulfuric acid. He says that up to 80 per cent of the surface ice in some spots may be concentrated sulfuric acid, and suggests this may be a veneer formed by surface bombardment with sulfur atoms originally thrown out from volcanoes on Io, another of Jupiter's moons.

Left: high resolution close-up of Europa's cracked surface, with the veiny, vermillion capillaries that intrigue geologists and astrobiologists. Shown in false color, the images of Europa highlight the coarse ice in blue and the mineral-rich cracks in red and brown. The blue-ice is the older layer of nearly pure frozen water. The northern hemisphere in particular is tinted brown with mineral deposits like magnesium sulfate (Epsom salts) contaminating the ice. Sir Arthur C. Clarke wrote the following famous and enigmatic passage in his novel, 2010: Odyssey 2: "All these worlds are yours - except Europa. Attempt no landing there." Right: double-ridge pattern characteristic of close views of the Europan ice pack. Image credits: NASA/Galileo. Other scientists think the results suggest that the acid derives from Europa's internal ocean. Tom McCord of the Planetary Science Institute in Winthrop, Washington State, points out that the greatest concentrations of acid seem to be in areas where the disrupted surface suggests that ocean liquid has gushed upward and frozen. McCord thinks that the acid on the surface began as salts from the ocean underneath—largely magnesium and sodium sulfates. Intense surface radiation caused chemical reactions, he says, which left an icy crust containing a high concentration of sulfuric acid as well as other sulfur compounds. Jeff Kargel of the US Geological Survey in Flagstaff, Arizona, believes the sulfuric acid is coming directly from the ocean. He thinks that Europa's heart is rocky, with undersea volcanoes releasing sulfur-containing compounds and oxygen that react with the ocean water to form sulfuric acid. "Europa has an Io hiding underneath the ocean," he says. If the surface sulfates have come from the water deep below, Europa's ocean might bean "acidic sulfate brine." That could be bad news for life, as strong acids tend to destroy organic compounds. But it doesn't rule out the possibility—some terrestrial species of bacteria thrive in environments with a pH as low as zero. Another blow to researchers hoping to probe this ocean for life comes from hints that Europa is much hillier than previously thought. Paul Schenk of the Lunar and Planetary Institute reports that a dark spot on Europa's surface is a 350-meter depression situated near a 900-meter rise—a total relief of 1250 meters. To support such a large relief, he calculates that the ice layer must be 10 to 30 kilometers thick, which is a daunting distance for any probe to drill

through. However, researchers are unlikely to find out much more from Galileo's data. Its measurements cover only a small fraction of Europa's surface, and much of the detail is obscured by background "noise" and low resolution. "I don't think we're going to have a definite answer until we get back with better spectrometers, better resolution, and maybe a lander," McCord told New Scientist. Figuring out how to do that is part of his job as a member of the science team for the Jupiter Icy Moons Orbiter, due to launch in 2012. "If the surface is made of sulfuric acid, landing should not be a problem as long as the ice stays frozen," he says. But if it becomes liquid, the acid could be strong enough to eat through most materials used to make spacecraft. That may give pause to proposals for a probe that melts through the surface to study the ocean below. Read the original article at http://www.astrobio.net/news/article838.htm. An additional article on this subject is available at http://www.spacedaily.com/news/jupiter-europa-04a.html. LIFE IN THE UNIVERSE TAKES ORDERS FROM SPACE Arizona State University release 20 February 2004 A century ago, when biologists used to talk about the primordial soup from which all life on Earth came, they probably never imagined from how far away the ingredients may have come. Recent findings have the origins of life reaching far out from what was once considered "the home planet." Evolution on the early Earth may have been influenced by some pretty far-out stuff. In a paper published this week in the journal Science, Arizona State University Chemistry Professor Sandra Pizzarello claims that materials from as far away as the interstellar media could possibly have played an active role in establishing the chemistry involved in the origin of life on this planet. In the paper, Pizarello and her co-author Arthur L. Weber of the SETI Institute show that the exclusive chirality of the proteins and sugars of life on Earth—their tendency to be left- or right-handed, could in fact be due to the chemical contribution of the countless meteorites that struck the planet during its early history. This paper provides a plausible explanation for how, with a little help from outside, the chemistry of non-life—characterized by randomness and complexity—becomes the ordered and specific chemistry of life. Pizzarello studies meteorites and the chemicals housed within them. A particular type of meteorite—carbonaceous chondrites—holds particular interest. Carbonaceous chondrites are very primitive, stony meteorites that contain organic carbon. These meteorites are rare, but also very exciting for chemists interested in the origins of life on Earth and in the solar system. They contain amino acids—the molecules that make up proteins, and an essential part of the chemistry of life. According to Pizzarello, it has been known for the last century that there are large amounts of carbon, hydrogen and nitrogen—the so-called biogenic elements—in the cosmos. And that it is reasonable to assume that these elements might have undergone some amount of chemical evolution before life even began. According to Pizzarello, who studies meteorites from the collection at ASU (which has the largest university-owned collection in the world) the meteorites are the only evidence of chemical evolution scientists have in hand today. New techniques of meteorite analysis are leading to great breakthroughs in understanding where these meteorites came from and how they were formed. Even more exciting, work Pizzarello and her colleagues have recently published in Science explores what sort of contribution the chemical evolution represented by meteorites might have had on the early Earth. The paper addresses what has been a basic difficulty in relating the chemical evolution represented by meteorites and the origin of terrestrial life on Earth. According to Pizzarello, this problem is that chemical evolution—what we see in meteorites—is characterized by randomness, while terrestrial life relies on specificity and selection. For example, the meteorites contain over 70 amino acids. A mere 20 amino acids make up life's proteins. "There is a fundamental difficulty in trying to figure out how you go from confusion and randomness to functionality and specificity," said Pizzarello.


So far, only one trait has been found to be similar, to some extent, between amino acids in meteorites and biopolymers, that of L-"handedness" (chirality). Because organic molecules can be asymmetric if they have different groups attached to a carbon atom, they can arrange spatially in two ways, like the two hands, and be either left or right handed. All proteins involved in life on Earth are made up of L-amino acids, while sugars involved in life have a D structure. Scientists call this "homochirality." An overabundance (excess) of the L-form (the chemical name is enantiomer), has also been found in some amino acids in meteorites. Pizzarello and Weber devised an experiment to find whether or not the amino acids found with L-enantiomeric excess in meteorites could have transferred their asymmetry during organic syntheses on the early Earth. If so, the meteorites could have provided a constant influx of materials with this excess—especially during a period early in the solar system's history in which the Earth and other planets were pummeled heavily by meteorites. Pizzarello and Weber report in Science that in fact their experiment succeeded in proving this possibility. In the laboratory, when performing sugar syntheses in water, using reactions that modeled what may have existed on the early Earth, the asymmetry in the amino acids led to a similar asymmetry in the sugars. Pizzarello and Weber thus were able to conclude that the delivery of material from outer space via meteorites - despite the seeming randomness and complexity of these materials—could in fact have "pushed" chemical evolution on Earth toward homochirality. Pizzarello points out that these findings do not imply that life did not evolve on Earth, or that the meteorites were the only early source of enantiomeric excess—only that the steady contribution of these meteorites might have provided a nudge in the "right" (or, more accurately, "left") direction. Read the original news release at http://www.asu.edu/asunews/research/ordersfromspace_022004.htm. An additional article on this subject is available at http://www.spacedaily.com/news/life-04r.html. SEEKING NEW EARTHS? LOOK FOR DUST Harvard-Smithsonian Center for Astrophysics release 04-08 20 February 2004 If alien astronomers around a distant star had studied the young Sun four-and-a-half billion years ago, could they have seen signs of a newly-formed Earth orbiting this innocuous yellow star? The answer is yes, according to Scott Kenyon (Smithsonian Astrophysical Observatory) and Benjamin Bromley (University of Utah). Moreover, their computer model says that we can use the same signs to locate places where Earth-size planets currently are forming-young worlds that, one day, may host life of their own. The key to locating newborn Earths, say Kenyon and Bromley, is to look not for the planet itself, but for a ring of dust orbiting the star that is a fingerprint of terrestrial (rocky) planet formation. "Chances are, if there's a ring of dust, there's a planet," says Kenyon. Good planets are hard to find Our solar system formed from a swirling disk of gas and dust, called a protoplanetary disk, orbiting the young Sun. The same materials are found throughout our galaxy, so the laws of physics predict that other star systems will form planets in a similar manner. Although planets may be common, they are difficult to detect because they are too faint and located too close to a much brighter star. Therefore, astronomers seek planets by looking for indirect evidence of their existence. In young planetary systems, that evidence may be present in the disk itself, and in how the planet affects the dusty disk from which it forms. Large, Jupiter-sized planets possess strong gravity. That gravity strongly affects the dusty disk. A single Jupiter can clear a ring-shaped gap in the disk, warp the disk, or create concentrated swaths of dust that leave a pattern in the disk like a wake from a boat. The presence of a giant planet may explain the wake-like pattern seen in the disk around the 350 million-year-old star Vega. Small, Earth-sized worlds, on the other hand, possess weaker gravity. They affect the disk more weakly, leaving more subtle signs of their presence.

Rather than looking for warps or wakes, Kenyon and Bromley recommend looking to see how bright the star system is at infrared (IR) wavelengths of light. (Infrared light, which we perceive as heat, is light with longer wavelengths and less energy than visible light.) Stars with dusty disks are brighter in the IR than stars without disks. The more dust a star system holds, the brighter it is in the IR. Kenyon and Bromley have shown that astronomers can use IR brightnesses not only to detect a disk, but also to tell when an Earth-sized planet is forming within that disk. "We were the first to calculate the expected levels of dust production and associated infrared excesses, and the first to demonstrate that terrestrial planet formation produces observable amounts of dust," says Bromley. Building planets from the ground up The most prevalent theory of planet formation calls for building planets "from the ground up." According to the coagulation theory, small bits of rocky material in a protoplanetary disk collide and stick together. Over thousands of years, small clumps grow into larger and larger clumps, like building a snowman one handful of snow at a time. Eventually, the rocky clumps grow so large that they become full-fledged planets. Kenyon and Bromley model the planet formation process using a complex computer program. They "seed" a protoplanetary disk with a billion planetesimals 0.6 miles (1 kilometer) in size, all orbiting a central star, and step the system forward in time to see how planets evolve from those basic ingredients. "We made the simulation as realistic as we could and still complete the calculations in a reasonable amount of time," says Bromley. They found the planet formation process to be remarkably efficient. Initially, collisions between planetesimals occur at low velocities, so colliding objects tend to merge and grow. At a typical Earth-Sun distance, it takes only about 1000 years for 1-kilometer objects to grow into 100-kilometer (60-mile) objects. Another 10,000 years produces 600-mile-diameter protoplanets, which grow over an additional 10,000 years to become 1200-mile-diameter protoplanets. Hence, Moon-sized objects can form in as little as 20,000 years. As planetesimals within the disk grow larger and more massive, their gravity grows stronger. Once a few of the objects reach a size of 600 miles, they begin "stirring up" the remaining smaller objects. Gravity slingshots the smaller, asteroid-sized chunks of rock to higher and higher speeds. They travel so fast that when they collide, they don't merge-they pulverize, smashing each other apart violently. While the largest protoplanets continue to grow, the rest of the rocky planetesimals grind each other into dust. "The dust forms right where the planet is forming, at the same distance from its star," says Kenyon. As a result, the temperature of the dust indicates where the planet is forming. Dust in a Venus-like orbit will be hotter than dust in an Earth-like orbit, giving a clue to the infant planet's distance from its star. The size of the largest objects in the disk determines the dust production rate. The amount of dust peaks when 600-mile protoplanets have formed. "The Spitzer Space Telescope should be able to detect such dust peaks," says Bromley. Currently, Kenyon and Bromley's terrestrial planet formation model covers only a fraction of the solar system, from the orbit of Venus to a distance about halfway between Earth and Mars. In the future, they plan to extend the model to encompass orbits as close to the Sun as Mercury and as distant as Mars. They also have modeled the formation of the Kuiper Belt-a region of small, icy and rocky objects beyond the orbit of Neptune. The next logical step is to model the formation of gas giants like Jupiter and Saturn. "We're starting at the edges of the solar system and working inward," Kenyon says with a grin. "We're also working out way up in mass. The Earth is 1000 times more massive than a Kuiper Belt object, and Jupiter is 1000 times more massive than the Earth." "Our ultimate goal is to model and understand the formation of our entire solar system." Kenyon estimates that their goal is attainable within a decade,


as computer speed continues to increase, enabling the simulation of an entire solar system. This research was published in the February 20, 2004, issue of The Astrophysical Journal Letters. Additional information and animations are available online at http://cfa-www.harvard.edu/~kenyon/. 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. Contacts: David Aguilar, Director of Public Affairs Harvard-Smithsonian Center for Astrophysics Phone: 617-495-7462 Fax: 617-495-7468 E-mail: [email protected] Christine Pulliam Public Affairs Specialist Harvard-Smithsonian Center for Astrophysics Phone: 617-495-7463 Fax: 617-495-7016 E-mail: [email protected] Read the original news release at http://cfa-www.harvard.edu/press/pr0408.html. Additional articles on this subject are available at: http://www.astrobio.net/news/article839.htm http://spaceflightnow.com/news/n0402/21dust/ http://www.universetoday.com/am/publish/look_dust_find_earths.html. INNOVATIVE WEB SITE BRINGS MARS EXPLORATION TO DESKTOPS NASA/JPL release 2004-067 20 February 2004 NASA's Jet Propulsion Laboratory, Pasadena, CA, is enhancing the availability of all Mars rover images for students and the public by distributing them via the Internet. The images can be viewed on the NASA web site at http://marsrovers.jpl.nasa.gov as well as the educational web site, MarsQuest Online, at www.marsquestonline.org/mer. The sites allow anyone with an Internet connection to participate in the adventure of Mars exploration. MarsQuest Online is making the full set of images from Spirit and Opportunity available for public viewing, along with daily updates, in an integrated exploration and education environment. The site is a powerful example of inquiry-based learning and public engagement in the thrill of exploration and discovery. Dr. Eric De Jong of JPL heads the Science Data Visualization and Modeling team that produces images of the rovers and the martian surface. He's also the co-principal investigator for MarsQuest Online. "This is NASA's vision of 21st century exploration through the Internet, a shared experience of scientists, students and the public. The rovers' eyes are our eyes, and MarsQuest Online puts these eyes on your desktop." MarsQuest Online enables the public, educators and students to gain a sense of what it's like to explore another world. According to Principal Investigator Daniel Barstow, MarsQuest Online was created "to provide the public with a highly engaging and interactive experience while learning about Mars by directly exploring it, just as the scientists do." Students are able to learn more about the red planet by examining the most recent panoramic views of the two landing sites and the images of rocks and soil investigated by the instruments on the rovers' robotic arms. They can also follow the progress of the twin robotic field geologists as they navigate around the martian surface. Students will learn information about Mars and the search for water through an array of learning activities, such as an interactive feature that allows users to control 3-D virtual flyovers of prominent martian landform features. These activities support key elements of the National Science Education Standards, including core concepts of Earth and space science.

Adults will appreciate the site, with its daily updates and its intuitive point-and-click interface. Each image is visually organized so novice and expert users can easily navigate across the martian landscape through the eyes of the rovers. The site also provides current news about important scientific findings. With support from the National Science Foundation, Arlington, VA, MarsQuest Online was built in close collaboration with NASA's Mars visualization team. It extends the power of NASA's very popular Mars Web site http://marsrovers.jpl.nasa.gov to offer a more in-depth exploration environment for the images. "The design of MarsQuest Online is based on extensive research on the most effective methods of using images and visualizations as tools by students and the general public," said Barstow, who also serves as director of the Technical Education Research Center (Terc) for Science Teaching and Learning in Cambridge, Mass. Barstow emphasized that "research findings show that most people can grasp concepts more quickly and intuitively by interacting with visual imagery than by simply reading text. With MarsQuest Online, students experience authentic science, venturing into the unknown, asking questions and pursuing answers." MarsQuest Online is funded by the National Science Foundation Informal Science Education Division and developed through collaboration between the Technical Education Research Center, the Space Science Institute in Boulder, CO, and JPL. The Technical Education Research Center is a non-profit educational research and development organization that specializes in inquiry-based science, math and technology education. The Space Science Institute is a science and education research and development organization that created the traveling MarsQuest museum exhibit associated with MarsQuest Online. JPL manages the Mars Exploration Program for NASA and provides the technical expertise on Mars rovers and the rover imaging systems. Internet mirroring support for high-bandwidth use of this site is provided by the University Corporation for Atmospheric Research, Boulder, CO, and the San Diego Supercomputing Center. For more information on the Mars Exploration Rover mission visit http://marsrovers.jpl.nasa.gov. To learn how to make your own 3-D images of Mars images, see http://www.jpl.nasa.gov/news/features/3d.cfm. Contacts: Natalie Godwin Jet Propulsion Laboratory, Pasadena, CA Phone: 818-354-0850 David Shepard Technical Education Research Center (Terc), Cambridge, MA Phone: 617-547-0430 James Harold Space Science Institute, Boulder, CO Phone: 720-974-5858 UNIVERSE HAS AT LEAST 30 BILLION YEARS LEFT By Robert Roy Britt 20 February 2004 Recent Hubble Space Telescope images of distant exploding stars add further confirmation to the permanence of a mysterious, repulsive force called dark energy that appears to dominate the universe. While scientists are not ready to close the case, they said today that dark energy, which is thought to permeate the cosmos and work in opposition to gravity, does appear to be a constant presence as predicted. The results bolster a theory that the universe won't end soon. But they leave researchers no more informed about the actual nature of dark energy. "We still have almost no clue what it is," said study leader Adam Riess of the Space Telescope Science Institute (STScI) in Baltimore. Dark energy was conjured to explain a phenomenal discovery in 1998. Nearly all galaxies in the universe are receding from each other at an ever-faster pace.


Read the full article at http://www.space.com/scienceastronomy/dark_energy_040220.html. NASA SELECTS 22 PROJECTS TO ADVANCE HUMAN SUPPORT TECHNOLOGIES NASA release 04-066 20 February 2004 NASA's Office of Biological and Physical Research recently selected 22 researchers to receive grants of up to four years to conduct research and development in advanced human support technologies. These technologies are expected to have a significant impact on the ability of humans to conduct long-duration space flight missions safely. Benefits to the quality of life on Earth from improved environmental technologies may also result from this research. The proposals were selected for one-to-four-year efforts, and are potentially worth $16.5 million over four years. Work under these grants will enhance safe human space flight in both low earth orbit, where the International Space Station operates, and in exploration of the solar system beyond low earth orbit. Five of the grants are for new technologies in advanced environmental monitoring of space habitats. Three grants address strategies for advanced control systems or systems analysis. Two projects are for biomass production. Four projects focus on space human-factors engineering. Eight others address novel approaches to waste processing, including air revitalization, water recycling and treatment of solid wastes. NASA received 122 proposals in response to a NASA Research Announcement, which was released in March 2003. The proposals were peer-reviewed by scientific and technical experts from academia, government and industry before selections were made. In addition to technical and scientific merit, selection criteria also included cost, relevance to NASA programs and feasibility of utilization by NASA. For a listing of the selected researchers, listed by state, along with their institutions and their research titles, visit http://research.hq.nasa.gov/code_u/nra/current/NRA-03-OBPR-01/winners.html. For more information on space research, visit http://spaceresearch.nasa.gov/. Contact: Dolores Beasley NASA Headquarters, Washington, DC Phone: 202-358-1753 An additional article on this subject is available at http://www.universetoday.com/am/publish/ nasa_awards_research_grants.html. SDL RECEIVES CONTRACT TO RESEARCH PLANTS FOR SPACE TRAVEL Space Dynamics Laboratory release 20 February 2004 In preparation for current and future space endeavors, NASA awarded the Space Dynamics Laboratory (SDL) a $750,000 contract to research the best types of vegetables to grow in space, how to clean them and the psychological effects they have on astronauts and cosmonauts. "We are saving NASA millions of dollars by building off the existing technology we have developed with our Russian partners," said Gail Bingham, Ph.D., chief scientist at SDL. SDL, a unit of Utah State University Research Foundation, teamed with the Russian Institute of Bio-Medical Problems (IBMP), built and operated the Svet growth chamber used on the Mir station. More recently the team developed Lada, a small growth chamber hosted in the Russian segment of the International Space Station (ISS).

This NASA contract will use Lada hardware to perform research to aid in developing procedures for a future large-scale growth chamber called the Vegetable Production Unit. Bingham said this is a new direction for space plant research. "This is really what we built Lada for," he said. "This is its first baseball game. It is going to be a really fun project." The contract involves three areas. The first is to research different types of plants and to check the plants' yields on the ground using Lada. SDL will then verify the plant yields performing the same experiments using Lada on the ISS. Food safety and diet needs are the second aspect of the NASA contract. SDL will perform research on the different types of plants to satisfy nutritional needs and different cultural backgrounds. To ensure astronaut health, SDL will work with the USDA to develop procedures for cleaning the vegetables for consumption. "Dirty fingerprints may be harmful to astronauts, so we are working out new procedures that will wash the lettuce or vegetable grown that will ensure food safety," said Bingham. "This protocol that may be used in growth chambers on the International Space Station, the Moon, Mars and the transit vehicles used to get there." The third aspect of the contract and the most important according to Bingham is the study of the psychological benefits the plants have on crew members. Jack Stuster, Ph.D., principal scientist of Anacapa Sciences will be working closely with SDL to evaluate the astronauts' journals to determine the psychological effects of vegetable production in space. "This is where we determine what the real value of plants in space. When we factor in the psychology of the astronauts, I believe plant development will come out to be of higher value than just shipping dehydrated food from the ground," said Bingham. "No one else has done this before—it is a first." The contract is a three-year study. Other team members include Bruce Bugbee, Ph.D., of Utah State University's plants, soils and biometeorology department and Jay Garland, Ph.D., of Dynamac Corporation at Kennedy Space Center. SDL will also be working cooperatively with the NASA Food Technology Commercial Space Center at Ames, Iowa. "I am happy to see it happening. Now we have a mission that will actually allow us to use our expertise to help NASA managers and people designing future space travel projects," said Bingham. An additional article on this subject is available at http://www.spacedaily.com/news/food-04b.html. MICROSCOPIC ASTRONAUTS By Tony Phillips From NASA Science News 23 February 2004 There are trillions of microbes orbiting Earth onboard the International Space Station (ISS). And that's just in the gut of one astronaut. Astronauts, like everyone else, carry microbes with them wherever they go. There are 1014 in the colon, trillions more on your hands, and in your mouth. The math is simple: microbes outnumber people, in space and on Earth, by a staggering factor. In fact, says Cheryl Nickerson of Tulane University Health Sciences Center, "there are more bacterial cells in your body than human cells." Many are beneficial. Some of the bacteria in our stomachs, for instance, produce vitamin K needed for the proper clotting of blood. Others help digest food. Even pathogens, in moderation, lend a hand by stimulating the immune system. In short: people need bugs. With NASA planning to send people back to the Moon and on to Mars, researchers are increasingly focused on the question, "what does space travel do to the human body?" An inseparable question is, "what does space travel do to microbes?"


There's already some evidence that microorganisms behave oddly in a weightless environment. In her laboratory at Tulane, Nickerson has floated some Salmonella bacteria in a rotating wall bioreactor—a device designed by NASA that simulates low gravity. The bioreactor is a fluid-filled habitat for bacteria. Shaped like a cylinder, it slowly rotates, gently tumbling microbes inside. Bacteria in the bioreactor never hit bottom, they hang suspended in their liquid growth medium, much as they would in Earth orbit. "It isn't real microgravity," notes Nickerson, "but it does approximate some aspects of weightlessness." In the bioreactor, Salmonella changes. The 2nd-leading cause of gastric distress in the USA gets even worse than usual. Its ability to cause disease is increased, says Nickerson. Pseudo-weightlessness makes the Salmonella more resistant to stomach acids and to heat. The bacteria also do a better job eluding macrophages, which are disease-fighting cells in your immune system. Scary. But the news isn't all bad. Some bacteria can produce helpful antibiotics, and they seem to produce more in space than on Earth—as much as 200% more according to mid-1990 space shuttle experiments sponsored by pharmaceutical company Bristol-Meyers Squib and partner BioServ Space Technologies. "These changes are a result of altered genetic expression," says Nickerson. Somehow weightlessness signals the genes of these microbes, commanding them to do things differently. In Salmonella, for instance, 163 genes (out of about 4600 total) changed their levels of expression—becoming more or less active than usual—inside the bioreactor. "The affected genes covered the full range of cell function: metabolism, structure, movement, virulence factors. You name it."

The Yeast GAP apparatus. "GAP" is short for Group Activation Pack.

Researchers are only beginning to understand these sweeping changes. Are some microbes more sensitive to space travel than others? Which genes are most altered? And how does this affect people? An experiment on the ISS, called "Yeast GAP," aims to find out. Nickerson is the principle investigator (PI) for the experiment. She works closely on the project with her Co-PI, Tim Hammond of Tulane University Health Sciences Center and the Veterans Affairs Medical Center in New Orleans. "Last month, we sent 16 vials of brewer's yeast to the space station onboard a Russian Progress supply rocket," says Hammond. In orbit, space station science officer Mike Foale gave the yeast some nutrient soup, and they began to reproduce. The population of cells grew ten-fold in only 30 minutes—"that's about five generations of yeast," notes Hammond. Then Foale flooded

the growth chamber with a fixative agent, to stop the population explosion and preserve the cells for analysis back on Earth.

ISS science officer Mike Foale activates the Yeast GAP experiment onboard the ISS. Nickerson and Hammond "can't wait to get the yeast back" to their labs in Louisiana, because, they believe, the cells are going to teach them a lot about genetic activity in space. "These are no ordinary yeast cells," notes Nickerson. "They've been genetically engineered" to reveal their secrets. Hammond explains, "Yeast cells have 6312 distinct genes, so scientists have created 6312 different varieties of yeast. Each variety has one gene 'knocked out' and replaced with a barcode pattern of nucleotides." These barcodes are like dog tags; by reading them, researchers can tell which gene has been knocked out of a particular yeast cell. All 6312 types were sent to the ISS, and all 6312 have had their opportunity to grow there. Which varieties grew best? Which ones fared poorly? Nickerson and Hammond will find out when the samples are returned to Earth (on some future shuttle flight). Using DNA microarray analysis, they will sort the yeast cells by barcode and count them, and compare the results to identical samples grown on Earth. This simple procedure will reveal genetic activity and pinpoint the genes yeast needed most to thrive in orbit. Simple, but ingenious. Read the original article at http://science.nasa.gov/headlines/y2004/23feb_yeastgap.htm. STUDY MOVES IN ON WHY ASTRONAUTS SUFFER BONE LOSS University of California—San Francisco release 23 February 2004 A new study by researchers at San Francisco VA Medical Center (SFVAMC) moves in on the physiological basis for the bone density loss experienced by people subjected to prolonged periods of bed rest and by astronauts who fly lengthy missions under the weightless conditions of space. The work, conducted in rats, is an important step toward developing therapies to prevent such bone loss, says senior author Daniel Bikle, MD, co-director of the Special Diagnostic and Treatment Unit at SFVAMC and professor of medicine and dermatology at University of California, San Francisco. Lead author of the study is Takeshi Sakata, who was a postdoctoral fellow in Dr. Bikle's laboratory at the time of the study and is now an orthopedic surgeon at the Kitade Hospital in Gobo, Wakayama, Japan. The current study builds on animal work Bikle and Sakata published last year, which showed that when bones are relieved of the burden of bearing weight, bone precursor cells fail to respond to insulin-like growth factor one or IGF-I, a biochemical regulator that plays a key role in the proliferation of most cell types. Now Bikle and his team have found that this lack of response occurs because IGF-I does not activate its receptor molecule on the surface of the cells. In addition, the researchers found that the interaction failure is probably triggered by a loss of integrins, proteins found in the membranes of bone cells that enable these cells to sense mechanical changes in their immediate environment. These integrins are also known to regulate the action of growth


factors in other cells. The study appears in the March issue of the Journal of Bone and Mineral Research. "Up until now, researchers have not demonstrated this signaling feedback loop in bone," says Bikle. "But it makes sense: Integrins are mechano-sensors. When the bone is moving and bearing weight, the integrins initiate a signaling process within the cell. This signal, in turn, impacts IGF-I's ability to activate its receptor signaling system inside the cell." When a limb is immobilized in a cast, when an astronaut experiences zero gravity, or whenever a person lies down, the weight-bearing bones of the body such as those in the spine and leg, are relieved of their burden, a condition known as skeletal unloading. When skeletal unloading persists for several weeks, bones start to deteriorate: the number of bone cells decreases, movement into the bone of such minerals as calcium and phosphorous slows, and production of bone-cell precursors called osteoprogenitor cells diminishes. All these changes result in weakened, brittle bones prone to fracture. While the bones of children may be able to eventually recover from such changes, adult bones have a harder time of it. Studies of Skylab and Salyut-6 long-term space missions (28-184 days) have found that, not only did astronauts on board the craft lose bone density during their missions, but five years later they had failed to recover to pre-launch bone density levels. "The big problem that NASA is facing in their plans to send a manned flight to Mars is how to get people there and back without having their skeletons turn to matchsticks," Bikle says. "Yet discovering a way to stop bone loss from skeletal unloading will impact more than just a few astronauts. Anyone who is immobilized in any way for a long period of time can benefit." To track the mechanism of bone loss, Bikle and his team devised a way of taking the weight off a rat's hindquarters while maintaining normal weight and movement in the animal's front legs. With hindquarters suspended by a freely moving line tethered to the cage lid (much like the pole that connects a bumper-car to the ceiling, allowing it to move anywhere on the floor), the rats moved around, groomed, ate and otherwise managed with just their forelimbs in the same way as their untethered companions during the 14-day trial period. The research team observed the animals carefully for symptoms of stress and also analyzed blood samples for stress hormones, but found no indications of stress in either the skeletal unloaded rats or their untethered companions. In order to be able to follow IGF-1 pathways, the team used a special line of dwarf laboratory rats that do not produce their own growth hormone. Half the animals in both the tethered and untethered groups were given IGF-1, while all rats in both groups were injected with a compound that traces actively dividing cells. At the end of the trial period, the team found that the numbers of precursor bone cells in the forelimbs of rats that had received IGF-1 was double that of rats that had not received the growth factor. But in the "unloaded" hind limbs, cell division was virtually stalled, regardless of whether animals had received the growth factor or not. The team then cultured cells from loaded and unloaded bones and put the cells through numerous biochemical assays looking for the point in the bone formation pathway that is blocked when bones are unloaded. They found that while IGF-I bound normally to its receptor, activation of the receptor did not take place. This activation is required for IGF-I to stimulate cells to grow. Bikle and his team then found that this same inhibition of the ability of IGF-I to activate its receptor could be duplicated by inhibiting integrin function. This fit neatly into their observation that integrin levels were reduced by skeletal unloading, These observations link the loss of integrins to the failure of IGF-I to activate its receptor. "The next step," Bikle says, "is to determine what's impeding production of integrin during skeletal unloading, and what the mechanism is that links the integrin signaling pathway to the IGF-I receptor activation. Once we understand these processes, we'll have some targets that we can address to help us devise interventions to prevent bone loss from skeletal unloading." Based on his current findings, Bikle speculates that such interventions will be based either on finding a way to reproduce the beneficial effects of integrin signaling, or of figuring out how to bypass the signaling pathway that is initiated by the interaction of IGF-I and its receptor. Other authors of the study are Yongmei Wang, MD, PhD, postdoctoral fellow in endocrinology at SFVAMC and in medicine at UCSF; Bernard Halloran, PhD, biochemist in endocrinology at SFVAMC and adjunct professor of

endocrinology at UCSF; Hashem Z. ElAlieh, BS, research associate in endocrinology at SFVAMC, and Jay Cao, PhD, postdoctoral fellow in endocrinology at SFVAMC and UCSF. The study was funded by grants from NASA and the National Institutes of Health. An additional article on this subject is available at http://spaceflightnow.com/news/n0402/23boneloss/. PLANETARY DEFENSE: PLANNING WITH PHANTOM ASTEROIDS By Leonard David From Space.com 24 February 2004 Authorities in defending the Earth from a cosmic run-in with an asteroid or comet have gathered here to detail ways to thwart future impacts and deal with the calamity if our planet is struck. An international group of scientists, engineers, space policy makers, and others are taking on the task of improving our ability to successfully defend our planet from possible impact threats. Attention is focused on four fictitious Defined Threat (DEFT) scenarios that endanger the Earth. The approaching virtual asteroids have been dubbed D'Artagnon, Athos, Aramis, and a long-period comet called Porthos. At this time, none of these names is assigned to a real asteroid or comet. The DEFT scenarios—which include various trajectories and time-to-impact assumptions—are meant to spur designs of rendezvous, intercept and deflection missions and spark discussion of how the world community might prepare for mitigation efforts or possible disaster from policy, public education, and other perspectives. Read the full article at http://www.space.com/scienceastronomy/asteroid_defense_040224.html. ESA PREPARES FOR NEXT MISSIONS TO MARS ESA release 25 February 2004 Before humans can leave footprints on the surface of Mars, many questions have to be answered and many problems solved. One of the most fundamental questions is whether life has ever existed on Mars. In its long-term Aurora Programme of Solar System exploration, ESA is preparing a series of robotic missions that will reveal the Red Planet's secrets and pave the way for future human expeditions. A major step in this ambitious program was completed this week with the selection of two industrial teams to carry out the detailed design of the ExoMars rover and its payload of scientific instruments called "Pasteur". These teams will be responsible for producing a detailed design concept for the rover, the first vehicle of its kind to be built by ESA. ExoMars will be ESA's first mission to carry "exobiology" instruments, meaning they are specifically designed to search for life.

Artist's view of the ExoMars Rover. Image credit: ESA.


Over the next few months ESA scientists will define a multi-instrument package that will be able to carry out a number of key tasks. It should be able to drill into the surface, retrieve and analyze samples, study the physical environment and look for evidence of biomarkers—clear signs that life has existed on Mars in the past, or even survives to the present day. ExoMars, which is scheduled for launch in 2009, will include an orbiter and a descent module that will land a highly mobile rover, weighing up to 200 kilograms, on the surface of Mars. After delivery of the lander and rover, the orbiter will operate as a data relay satellite between the Earth and the vehicle on the surface. The main aim of the rover and its state-of-the-art Pasteur payload will be to search for signs of life, past or present, on the Red Planet. Pasteur will be the most comprehensive scientific package ever to land on Mars, with tools that can extract, handle and analyze samples of martian soil. Its unique capability to obtain underground samples at depths of up to two meters will provide an excellent opportunity to gain access to ice-rich soil layers—and possibly the first definitive evidence of primitive martian life. Read the original news release at http://www.esa.int/export/SPECIALS/Mars_Express/ SEM3X32PGQD_0.html. An additional article on this subject is available at http://spaceflightnow.com/news/n0402/23marslife/. GREENHOUSES FOR MARS By Karen Miller From NASA Science News 25 February 2004 Confused? Then you're just like plants in a greenhouse on Mars. No greenhouses exist there yet, of course. But long-term explorers, on Mars, or the moon, will need to grow plants: for food, for recycling, for replenishing the air. And plants aren't going to understand that off-earth environment at all. It's not what they evolved for, and it's not what they're expecting. But in some ways, it turns out, they're probably going to like it better! Some parts of it, anyway. "When you get to the idea of growing plants on the moon, or on Mars," explains molecular biologist Rob Ferl, director of Space Agriculture Biotechnology Research and Education at the University of Florida, "then you have to consider the idea of growing plants in as reduced an atmospheric pressure as possible."

An artist's concept of greenhouses on Mars. Image credit: NASA.

There are two reasons. First, it'll help reduce the weight of the supplies that need to be lifted off the earth. Even air has mass. Second, martian and lunar greenhouses must hold up in places where the atmospheric pressures are, at best, less than one percent of Earth-normal. Those greenhouses will be easier to construct and operate if their interior pressure is also very low—perhaps only one-sixteenth of Earth normal.

The problem is, in such extreme low pressures, plants have to work hard to survive. "Remember, plants have no evolutionary preadaption to hypobaria," says Ferl. There's no reason for them to have learned to interpret the biochemical signals induced by low pressure. And, in fact, they don't. They misinterpret them. Low pressure makes plants act as if they're drying out. In recent experiments, supported by NASA's Office of Biological and Physical research, Ferl's group exposed young growing plants to pressures of one-tenth Earth normal for about twenty-four hours. In such a low-pressure environment, water is pulled out through the leaves very quickly, and so extra water is needed to replenish it. But, says Ferl, the plants were given all the water they needed. Even the relative humidity was kept at nearly 100 percent. Nevertheless, the plants' genes that sensed drought were still being activated. Apparently, says Ferl, the plants interpreted the accelerated water movement as drought stress, even though there was no drought at all.

An experiment related to Ferl's: Lettuce growing in a low-pressure dome at the Kennedy Space Center.

That's bad. Plants are wasting their resources if they expend them trying to deal with a problem that isn't even there. For example, they might close up their stomata—the tiny holes in their leaves from which water escapes. Or they might drop their leaves altogether. But, those responses aren't necessarily appropriate. Fortunately, once the plants' responses are understood, researchers can adjust them. "We can make biochemical alterations that change the level of hormones," says Ferl. "We can increase or decrease them to affect the plants' response to its environment." And, intriguingly, studies have found benefits to a low pressure environment. The mechanism is essentially the same as the one that causes the problems, explains Ferl. In low pressure, not only water, but also plant hormones are flushed from the plant more quickly. So a hormone, for example, that causes plants to die of old age might move through the organism before it takes effect. Astronauts aren't the only ones who will benefit from this research. By controlling air pressure, in, say, an Earth greenhouse or a storage bin, it may be possible to influence certain plant behaviors. For example, if you store fruit at low pressure, it lasts much longer. That's because of the swift elimination of the hormone ethylene, which causes fruit to ripen, and then rot. Farm produce trucked from one coast to the other in low pressure containers might arrive at supermarkets as fresh as if it had been picked that day. Much work remains to be done. Ferl's team looked at the way plants react to a short period of low pressure. Still to be determined is how plants react to spending longer amounts of time—like their entire life—in hypobaric conditions. Ferl also hopes to examine plants at a wider variety of pressures. There are whole suites of genes that are activated at different pressures, he


says, and this suggests a surprisingly complex response to low pressure environments.

Peas growing onboard the International Space Station. Ferl's research will improve greenhouses not only on other planets, but also on spaceships. To learn more about this genetic response, Ferl's group is bioengineering plants whose genes glow green when activated. In addition they are using DNA microchip technology to examine as many as twenty-thousand genes at a time in plants exposed to low pressures. Plants will play an extraordinarily important role in allowing humans to explore destinations like Mars and the moon. They will provide food, oxygen and even good cheer to astronauts far from home. To make the best use of plants off-Earth, "we have to understand the limits for growing them at low pressure," says Ferl. "And then we have to understand why those limits exist." Ferl's group is making progress. "The exciting part of this is, we're beginning to understand what it will take to really use plants in our life support systems." When the time comes to visit Mars, plants in the greenhouse might not be so confused after all. Read the original article at http://science.nasa.gov/headlines/y2004/25feb_greenhouses.htm. EARTH AT RISK: NEW CALLS FOR PLANETARY DEFENSE By Leonard David From Space.com 25 February 2004 It is past time to get serious about planetary defense, experts say. The threat of Earth being on the receiving end of a cosmic calling card in the form of an asteroid or comet is real. Despite increasing scientific agreement regarding the danger posed by near-Earth objects smashing into our planet, governmental steps to deal with the issue are missing-in-action. At present, only patchwork and under-funded research efforts are underway to robustly detect, track, catalog and plot out strategies to thwart menacing asteroids and comets that place Earth at risk. An international confab of experts is taking part in The Planetary Defense Conference: Protecting Earth from Asteroids here (Garden Grove, CA) this week and sponsored by The Aerospace Corporation and the American Institute of Aeronautics and Astronautics (AIAA). Read the full article at http://www.space.com/scienceastronomy/planetary_defense_040225.html.

NEW ADDITIONS TO THE ASTROBIOLOGY INDEX By David J. Thomas http://www.lyon.edu/projects/marsbugs/astrobiology/ 25 February 2004 Astrobiology and planetary engineering articles http://www.lyon.edu/projects/marsbugs/astrobiology/online_articles1.html ESA, 2004. Europe prepares mission to search for life on Mars. Spaceflight Now. New Scientist, 2004. Is Europa corrosive? Astrobiology Magazine. Human space exploration articles http://www.lyon.edu/projects/marsbugs/astrobiology/online_articles3.html K. Miller, 2004. Greenhouses for Mars. NASA Science News. T. Phillips, 2004. Can people go to Mars? NASA Science News. T. Phillips, 2004. Microscopic astronauts. NASA Science News. Space Dynamics Laboratory, 2004. SDL receives contract to research plants for space travel. SpaceDaily. University of California—San Francisco, 2004. Study moves in on why astronauts suffer bone loss. Spaceflight Now. Evolution (biological, chemical and cosmological) articles http://www.lyon.edu/projects/marsbugs/astrobiology/online_articles5.html Arizona State University, 2004. Life in the universe takes orders from space. SpaceDaily. R. R. Britt, 2004. Universe has at least 30 billion years left. Space.com. T. Devitt, 2004. Intelligent design: the new 'big tent' for evolution's critics. SpaceDaily. S. Pizzarello and A. L. Weber, 2004. Prebiotic amino acids as asymmetric catalysts. Science, 303(5661):1151. Planetary protection articles http://www.lyon.edu/projects/marsbugs/astrobiology/online_articles6.html L. David, 2004. Earth at risk: new calls for planetary defense. Space.com. L. David, 2004. Planetary defense: planning with phantom asteroids. Space.com. Extrasolar planets articles http://www.lyon.edu/projects/marsbugs/astrobiology/online_articles7.html Harvard-Smithsonian Center for Astrophysics, 2004. A good planet is hard to find? Astrobiology Magazine. Harvard-Smithsonian Center for Astrophysics, 2004. Look for dust to find new Earths. Universe Today. Harvard-Smithsonian Center for Astrophysics, 2004. Seeking new Earths? Look for dust, researchers say. Spaceflight Now. CASSINI SIGNIFICANT EVENTS NASA/JPL release 12-18 February 2004 The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Tuesday, February 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://jpl.convio.net/site/R?i=h2pnGh6OG69O-3BCLCXxIg.


Cassini continues to take data for the first color Saturn and ring approach movies, ultraviolet mosaics of the Saturn magnetosphere, searches for previously undetected satellites, and long integrations of Saturn's rings in the mid-infrared to determine ring composition. Additional activities include uplink of the second set of Ion and Neutral Mass Spectrometer (INMS) diagnostic flight software, a Magnetometer Subsystem (MAG) boom alignment and calibration, Radio and Plasma Wave Science (RPWS) high frequency receiver calibrations, acquisition of optical navigation images, power-off of the Cassini Plasma Spectrometer (CAPS) Ion Mass Spectrometer sensor and power-on of the supplemental heater, clearing of the ACS high water marks, and a DSN array demonstration. Instrument Expanded Blocks for Visual and Infrared Mapping Spectrometer (VIMS), CAPS, Imaging Science Subsystem (ISS), Ultraviolet Imaging Spectrograph (UVIS), and Composite Infrared Spectrometer (CIRS) were uplinked to the spacecraft along with the C43 background sequence and a CIRS Mission Sequence Subsystem version D10.1 trigger mini-sequence. C43, the second of the approach science sequences, begins execution on Thursday February 19. A science allocation planning meeting for development of C44 was held this week. There were four days and almost 3000 MB of additional data bits available to be shared by CAPS, Cosmic Dust Analyzer, CIRS, MAG, Magnetospheric Imaging Instrument, RPWS, and VIMS. Radio Science Gravitational Wave Experiment #1 data archive volume for the Planetary Data System has been distributed to the Radio Science Team for review. This volume will be used as a template for future radio science archive volumes. In the last week, 331 ISS images were returned and distributed. So far in C42, 540 ISS images, 52 of them optical navigation images, have been returned. In the last week, 46 VIMS cubes were played back and distributed. So far in C42, 416 VIMS cubes have been received. The Kinematic Prediction Tool / Inertial Vector Propagator analysis on the port #1 products for tour sequences S23 and S24 were delivered this week. In addition, the development process for Science Operations Plan implementation of S25 and S26 kicked off. The preliminary port#1 of the Aftermarket process for tour sequence S01 occurred this week. Mission Planning reported that the INMS team has begun simulating Titan A data and using a JPL generated trajectory in support of an exercise to train for estimating the actual Titan atmosphere during the Ta flyby in support of navigation planning for subsequent flybys. The activity will run for about two weeks. During this exercise, the existing atmosphere model will be modified, the trajectory used, and data to be gathered by INMS during the Ta flyby will be emulated. Then another INMS team will take the simulated data and translate it into an atmosphere model which can be extrapolated to 950 km. This is test #2 of this process. The first test uncovered some problems with the process that have since been corrected. A delivery coordination meeting was held for Multi-mission Image Processing Laboratory software version D31. An additional delivery will be held for

version D32.01 in late March to include updates for a VIMS modification and a telemetry processing option. A Software Review/Certification Requirements meeting was held for INMS flight software (FSW) version 7.0 The software will be uplinked to the SSR and then to INMS RAM during C44. This is a fully functional FSW build and not part of the diagnostic FSW builds currently operating on the instrument. Articles posted to the University of Arizona Science and Technology web site, CNN interactive, and MSNBC News focused on the study of oceans on other planets. The articles feature Titan and Cassini prominently. For more information go to http://jpl.convio.net/site/R?i=X28bgAOPTslO-3BCLCXxIg and http://jpl.convio.net/site/R?i=OEYbaCIdlrdO-3BCLCXxIg and http://jpl.convio.net/site/R?i=nJK3_pqz_oxO-3BCLCXxIg. 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. MARS EXPLORATION ROVER UPDATES NASA/JPL releases Opportunity Digs; Spirit Advances NASA/JPL release 2004-062, 17 February 2004 NASA's Mars Exploration Rover Opportunity has scooped a trench with one of its wheels to reveal what is below the surface of a selected patch of soil. "Yesterday we dug a nice big hole on Mars," said Jeffrey Biesiadecki, a rover planner at NASA's Jet Propulsion Laboratory, Pasadena, CA.

The Mars Exploration Rover Opportunity dragged one of its wheels back and forth across the sandy soil at Meridiani Planum to create a hole (center) measuring approximately 50 centimeters (19.7 inches) long by 20 centimeters (7.9 inches) wide by 9 centimeters (3.5 inches) deep. The rover's instrument deployment device, or arm, will begin studying the fresh soil at the bottom of the trench later today for clues to its mineral composition and history. Scientists chose this particular site for trenching because previous data taken by the rover's miniature thermal emission spectrometer indicated that it contains crystalline hematite, a mineral that sometimes forms in the presence of water. The brightness of the newly-exposed soil is thought to be either intrinsic to the soil itself, or a reflection of the Sun. This image was taken by the rover's hazard-avoidance camera. Image credit: NASA/JPL. The rover alternately pushed soil forward and backward out of the trench with its right front wheel while other wheels held the rover in place. The rover turned slightly between bouts of digging to widen the hole. "We took a patient, gentle approach to digging," Biesiadecki said. The process lasted 22 minutes. The resulting trench—the first dug by either Mars Exploration Rover—is about 50 centimeters (20 inches) long and 10 centimeters (4 inches) deep. "It came out deeper than I expected," said Dr. Rob Sullivan of Cornell University, Ithaca, NY, a science-team member who worked closely with engineers to plan the digging. Two features that caught scientists' attention were the clotty texture of soil in the upper wall of the trench and the brightness of soil on the trench floor,


Sullivan said. Researchers look forward to getting more information from observations of the trench planned during the next two or three days using the rover's full set of science instruments.

This mosaic image from the panoramic camera on the Mars Exploration Rover Spirit shows the area in front of the rover after its record 27.5 meters (90.2 feet) drive on Sol 43, which ended February 16, 2004. Spirit is looking toward one of its future targets, the rim of a crater nicknamed "Bonneville." Image credit: NASA/JPL/Cornell University. Opportunity's twin rover, Spirit, drove 21.6 meters closer to its target destination of a crater nicknamed "Bonneville" overnight Monday to Tuesday. It has now rolled a total of 108 meters (354 feet) since leaving its lander 34 days ago, surpassing the total distance driven by the Mars Pathfinder mission's Sojourner rover in 1997. Spirit has also begun using a transmission rate of 256 kilobits per second, double its previous best, said JPL's Richard Cook. Cook became project manager for the Mars Exploration Rover Project today when the former manager, Peter Theisinger, switched to manage NASA's Mars Science Laboratory Project, in development for a 2009 launch.

Left: this image, taken by an instrument called the microscopic imager on the Mars Exploration Rover Spirit, reveals an imprint left by another instrument, the Moessbauer spectrometer. The imprint is at a location within the rover wheel track named “Middle of Road.” Both instruments are located on the rover’s instrument deployment device, or “arm.” Scientists find this image particularly interesting because of the compacted nature of the soil that was underneath the Moessbauer spectrometer plate. Also of interest are the embedded, round grains and the fractured appearance of the material disturbed within the hole. The material appears to be slightly cohesive. The field of view in this image, taken on Sol 43 (February 16, 2004), measures approximately 3 centimeters (1.2 inches) across. Right: This elevation map of a soil target called “Peak” was created from images taken by the microscopic imager located on the Mars Exploration Rover Spirit’s instrument deployment device or “arm.” The image reveals the various high and low points of this spot of soil after the Moessbauer spectrometer, another instrument on the rover’s arm, was gently placed down on it. The blue areas are farthest away from the instrument; the red areas are closest. The variation in distance between blue and red areas is only 2 millimeters, or .08 of an inch. The images were acquired on sol 39 (February 11, 2004). Image credits: NASA/JPL/Cornell/USGS. Spirit's drive toward "Bonneville" is based on expectations that the impact that created the crater "would have overturned the stratigraphy and exposed it for our viewing pleasure," said Dr. Ray Arvidson of Washington University in St. Louis, deputy principal investigator for the rovers' science instruments. That stratigraphy, or arrangement of rock layers, could hold clues to the mission's overriding question—whether the past environment in the region of Mars where Spirit landed was ever persistently wet and possibly suitable for sustaining life. Both rovers have returned striking new pictures in recent days. Microscope images of soil along Spirit's path reveal smoothly rounded pebbles. Views

from both rovers' navigation cameras looking back toward their now-empty landers show the wheel tracks of the rovers' travels since leaving the landers. Each martian day, or "sol" lasts about 40 minutes longer than an Earth day. Opportunity begins its 25th sol on Mars at 10:59 PM Tuesday, PST. Spirit begins its 46th sol on Mars at 11:17 AM Wednesday, Pacific Standard Time. The two rovers are halfway around Mars from each other. Spirit Does a "Wheel Wiggle" (sol 45) 18 February 2004 Spirit began sol 45, ending at 11:17 AM February 18, 2004 PST, at its previous target, Halo, by conducting analysis with the alpha particle x-ray spectrometer, microscopic imager and Moessbauer spectrometer. Spirit also took panoramic camera images and miniature thermal emission spectrometer observations before its arm was stowed for the northeast drive toward a circular depression dubbed Laguna Hollow. The first 19 meters of the drive toward Laguna Hollow was commanded using go-to waypoint commands with the hazard avoidance system turned off. This mode—which was used for the first time this sol—provides automatic heading correction during a blind drive. Some fine-tuning toward the target brought the total drive for this sol to 22.7 meters (74.5 feet). After reaching Laguna Hollow, Spirit "wiggled" its wheels to disturb or scuff the fine dust-like soil at this location, which allows for more detailed observations with the instruments on the robotic arm. After adjusting position to put the disturbed soil in reach of the arm, Spirit backed up and completed a miniature thermal emission spectrometer scan of the new work area. Before the sol ended, Spirit made one more adjustment, putting it in perfect position to analyze the scuffed area beginning on sol 46. The plan for sol 46, which will end at 11:57 AM, February 19, 2004 PST, is to conduct observations on Laguna Hollow with the instruments on the robotic arm, including some higher resolution analysis that will involve an overnight tool change. Peering into the Hole (Opportunity sol 24) 18 February 2004

This picture, obtained by the microscopic imager on NASA's Opportunity rover during sol 24, February 17 PST, shows soil clods exposed in the upper wall of the trench dug by Opportunity's right front wheel on sol 23. The clods were not exposed until the trench was made. The presence of soil clods implies weak bonding between individual soil grains. The chemical agent or mineral that causes the dirt to bind together into a clod, which scientists call the "bonding agent," is currently unknown. Moessbauer and alpha particle X-ray spectrometer measurements of this spot, planned for sol 25, might help explain the bonding, which would ultimately help the rover team understand how geological processes vary across the red planet. In any case, the bonds


between soil grains here cannot be very strong because the wheel dug down through this layer with little trouble. Image credit: NASA/JPL/Cornell/USGS. On sol 24, which ended at 10:59 PM Tuesday, PST, Opportunity used science instruments on its robotic arm to examine the hole it dug with its right front wheel on sol 23. The trench is about 50 centimeters (20 inches) long by 20 centimeters (8 inches) wide by 10 centimeters (4 inches) deep. Sol 24's wake-up music was "Trench Town Rock" by Bob Marley. The plan for sol 25, which will end at 11:38 PM Wednesday, PST, is to continue examining the walls and floor of the trench for clues about the history of Mars. Opportunity will also peek at its right front wheel with the panoramic camera to see what materials got stuck on the wheel from the trenching activity. Then, Opportunity will use the panoramic camera high on the rover’s mast to check out a former piece of itself—the heat shield, which is sitting off in the distance. The heat shield protected the rover during cruise and during descent through the atmosphere on January 4, 2004, PST. Opportunity Examines Trench as Spirit Prepares to Dig One NASA/JPL release 2004-066, 19 February 2004 By inspecting the sides and floor of a hole it dug on Mars, NASA's Opportunity rover is finding some things it did not see beforehand, including round pebbles that are shiny and soil so fine-grained that the rover's microscope can't make out individual particles. "What's underneath is different than what's at the immediate surface," said Dr. Albert Yen, rover science team member at NASA's Jet Propulsion Laboratory, Pasadena, CA.

This image shows the shallow depression dubbed "Laguna Hollow" before the Mars Exploration Rover Spirit drove into it to sample its bed of fine sediments on the 45th sol or day, of its mission (February 18, 2004). The hollow provides scientists with a laboratory for studying the atmospheric processes that shaped Mars because, in contrast to surrounding rocky terrain, it contains windblown dust and possibly salty clumps of soil. Spirit is scheduled to dig a trench at the bottom of "Laguna Hollow" on sol 47. The image was taken by the rover's panoramic camera. Image credit: NASA/JPL/Cornell University. Meanwhile, NASA's other Mars Exploration Rover, Spirit, has reached a site with such interesting soil that scientists have decided to robotically dig a hole there, too. Spirit's trenching at a shallow depression dubbed "Laguna Hollow" could answer questions about whether traits on the soil surface resulted from repeated swelling and shrinking of an upper layer bearing concentrated brine, among other possibilities. Opportunity has manipulated its robotic arm to use its microscope on five different locations within the trench the rover dug on Monday. It has also taken spectrometer readings of two sites. "We've given the arm a very strenuous workout," said JPL's Dr. Eric Baumgartner, lead engineer for the arm. The accuracy of the tool placements—within 5 millimeters, or less than a quarter inch—is remarkable for mobile robotics on Earth, much less on Mars. Once data are analyzed from the alpha particle X-ray spectrometer and the Moessbauer spectrometer about what elements and what iron-bearing minerals are present, the differences between the subsurface and the surface will be easier to interpret, Yen said. While Opportunity has been digging and examining its trench this week, it has also been catching up on transmission of pictures and information from its survey last week of a rock outcrop along the inner wall of the small crater in which the rover is working. Both rovers can communicate directly with Earth, but JPL's Andrea Barbieri, telecommunication system engineer, reported that 66 percent of the 10 gigabits of data they have returned so far has come via relays by NASA's Mars Odyssey orbiter and another 16 percent via relays by NASA's Mars Global Surveyor.

This image, taken by the microscopic imager, an instrument located on the Mars Exploration Rover Opportunity's instrument deployment device, or "arm," reveals shiny, spherical objects embedded within the trench wall at Meridiani Planum, Mars. Scientists are highly intrigued by these objects and may further investigate them. The area in this image measures approximately 3 centimeters (1.2 inches) across. Image credit: NASA/JPL/USGS. Based on the outcrop survey, scientists have chosen a feature they have dubbed "El Capitan" as the next target for intensive investigation by Opportunity. "We've planned our assault on the outcrop," said Dr. Steve Squyres of Cornell University, Ithaca, NY, principal investigator for the rovers' science instruments. "The whole stack of rocks seems to be well exposed here," he said of the chosen target. Upper and lower portions appear to differ in layering and weathering characteristics. Planners anticipate that Opportunity's arm will be able to reach both the upper and lower parts from a single parking spot in front of "El Capitan." Halfway around the planet, Spirit will be told to use a front wheel to dig a trench during the martian day, or "sol," that will end at 12:36 PM Friday, PST. Some soil in "Laguna Hollow" appeared to stick to Spirit's wheels. Possible explanations include very fine-grained dust or concentrated salt making the soil sticky, said Dr. Dave Des Marais, a rover science team member from NASA Ames Research Center, Moffett Field, CA. Pictures of the surface there also show pebbles arranged in clusters or lines around lighter patches Des Marais described as "miniature hollows." This resembles patterned ground on Earth that can result from alternating expansion and shrinkage of the soil. Possible explanations for repeated expanding and contracting include cycles of freezing and thawing or temperature swings in salty soil. After trenching to seek clues about those possibilities, Spirit will continue on its trek toward the rim of a crater nicknamed "Bonneville," now estimated to be about 135 meters (443 feet) away from the rover. Spirit has already driven 128 meters (420 feet). JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA's Office of Space Science, Washington, DC. Images and additional information about the project are available from JPL at http://marsrovers.jpl.nasa.gov and from Cornell University at http://athena.cornell.edu. Halfway Through (Spirit sol 46) 19 February 2004 Sol 46, completed at 11:17 AM February 19, 2004 PST, marks the halfway point of Spirit's primary surface mission—sols 2 through 91. Spirit began this


momentous morning by doing some remote sensing of the crater rim and imaging the surrounding soil with the panoramic camera and miniature thermal emission spectrometer. After all this work, Spirit took a break with a nap lasting slightly more than an hour. After waking, Spirit continued its observations of the ground and sky with the miniature thermal emission spectrometer. At about 1:34 PM Mars Local Solar Time, Spirit found itself analyzing a patch of the atmosphere with the miniature thermal emission spectrometer at the same time that Mars Global Surveyor's thermal emission spectrometer was looking down through the same chunk of atmosphere. This concurrent observation will enable a more thorough understanding of martian atmospheric conditions. Spirit's afternoon activities began at about 4:00 PM Mars Local Solar Time after the Mars Global Surveyor pass. Spirit was expected to take stereo microscopic images of the target "Trout" in Laguna Hollow. This is the first time the microscopic imager will take pictures at Gusev Crater without the Moessbauer instrument first touching the surface of the soil. The observation will provide pictures of undisturbed soil. After this, Spirit will perform a calibration activity by imaging a location in the sky with the microscopic imager and the navigation camera simultaneously. Spirit's day will stretch into the night this sol with an overnight Moessbauer spectrometer integration. After a brief sleep, Spirit will wake at about 2:00 a.m. Mars Local Solar time on sol 47 to end the integration, collect the data and turn on the arm heaters. It will prepare for changing the tool from the Moessbauer to the alpha particle x-ray spectrometer, and begin observations with the new tool. Finally, the rover will leave the alpha particle x-ray spectrometer powered on and go back to sleep around 2:30 AM Mars Local Solar time. On the morning of Sol 47, which will end at 11:57 AM February 20, 2004 PST, the plan is for Spirit to end the alpha particle x-ray observation and collect that data, and then perform some early mini-thermal emission spectrometer soil properties observations. Stutter Stepping to El Capitan (Opportunity sol 25) 19 February 2004 On sol 25, which ended at 11:38 PM Wednesday, February 18, PST, Opportunity used the microscopic imager and alpha particle x-ray spectrometer to study the chemical makeup of the wall and floor area within the rover-made trench. Due to time constraints, Opportunity was unable to take a picture of the heat shield in the distance. Sol 25's wake-up music was "Fascination" by Human League. The plan for sol 26, which will end at 12:18 AM Friday, PST, is to back away from the trench, obtain one grand finale Moessbauer spectrometer reading of the trench, pick up and stow the rover arm, then turn and drive 9 meters (30 feet) to the El Capitan area. Opportunity will make a few intentional "stutter steps" on its way to El Capitan, stopping to take a few front hazard avoidance camera images and navigation camera images to plan for final approach and robotic arm activities. Opportunity will stop a couple of meters (about 6 or 7 feet) short of El Capitan to take images with its panoramic camera and gather science measurements with its miniature thermal emission spectrometer. On sol 27, Opportunity will make a short, closer approach to El Capitan to poise itself to use the rock abrasion tool and other instruments on the rover arm. Spirit Digs a Trench (sol 47) 20 February 2004 On sol 47, ending at 12:36 PM February 20, 2004 PST, engineers woke Spirit up to the song "Dig Down Deep," by Hot Soup, and that's exactly what Spirit proceeded to do. The two-hour operation performed by Spirit's left front wheel resulted in a trench 7-8 centimeters deep (2.8 to 3.1 inches) that uncovers fresh soil and possibly ancient information. Spirit dug this trench at "Laguna Hollow" the same way that Opportunity dug its 9-10 centimeter (3.5 to 3.9 inch) trench at Meridiani. However, because the ground at this location is harder, Spirit had to dig for twice as long as Opportunity—going back and forth over the surface 11 times instead of 6. After the trench was completed, Spirit backed up one meter, or more than a yard, and analyzed the area with the miniature thermal emission spectrometer before driving forward 0.4 meters (15.7 inches) and imaging the excavation site with the panoramic camera. A final move forward of another 0.4 meters

allowed Spirit to take front hazard avoidance camera images of the arm work volume which was then centered on the trench.

A view from the front hazard-avoidance camera of NASA's Spirit rover on its 47th martian day, or sol, shows a trench excavated by the rover's left front wheel within the "Laguna Hollow" area. The trench, dubbed "Road Cut," is 7 centimeters (3 inches) deep. The soil at this location is more cohesive than the material where Spirit's twin, Opportunity, dug its first trench at Meridiani Planum. Spirit made 11 back-and-forth passes to dig this trench, and still did not produce as deep a hole as Opportunity dug in 6 passes. Scientists and engineers plan to begin up-close inspection of the soil in this trench on sol 48 by placing the microscopic imager on the floor and the walls before conducting readings with the rover's Moessbauer and alpha particle X-ray spectrometers on some of the same points. Image credit: NASA/JPL. After stowing the arm, the rover did a series of miniature thermal emission spectrometer observations of several nearby rocks, "Buffalo," "Cherry," "Cotton," and "Jiminy Cricket," and a combined miniature thermal emission spectrometer and panoramic camera observation of "Beacon." Spirit also took panoramic camera images of its deck to observe dust accumulation on the instrumented solar cells and on the miniature thermal emission spectrometer calibration target. Spirit then took a siesta from 2:00 PM to 3:45 PM Mars Local Solar time and woke up for some more panoramic camera and miniature thermal emission spectrometer observations of "Beacon," and miniature thermal emission spectrometer ground and sky stares. All activities up through the afternoon pass by the Mars Odyssey orbiter were completed successfully. Enter the Rock Abrasion Tool (Opportunity sol 26) 20 February 2004 On sol 26, which ended at 12:18 AM Friday, February 19, PST, Opportunity successfully obtained one final Moessbauer spectrometer reading of the trench, stowed the rover arm, and drove 15 meters (50 feet) to the "El Capitan" area. The drive was Opportunity’s longest yet and required the vehicle and planners to skirt the trench and avoid the lander. The plan for sol 27, which will end at 12:57 AM Saturday, PST, is to first "supersize" the measurements of the "El Capitan" area with the panoramic camera, miniature thermal emission spectrometer, and microscopic imager. The mineralogy and geology teams have requested a minimum of three hours worth of "super resolution" and "super spectral" observations for the science instruments to get the most comprehensive coverage of this interesting site, which has varying textures and layers of dirt and rock. After a short siesta in the early afternoon, Opportunity will drive 30 centimeters (12 inches) to sneak a bit closer to the rocks in "El Capitan" to get


ready for the rock abrasion tool to do its work. After the drive, the Opportunity team plans to take a picture of the martian sky with the panoramic camera and miniature thermal emission spectrometer. If time permits, Opportunity will attempt to aim its cameras toward the heat shield in the far distance. Over the weekend, Opportunity plans to find the perfect spot to use the abrasion tool and set it loose to grind away on "El Capitan," which will be the first use of the rock abrasion tool by Opportunity. Down in the Trench (Spirit sol 48) 21 February 2004

NASA's Mars Exploration Rover Spirit casts a shadow over the trench that the rover is examining with tools on its robotic arm. Spirit took this image with its front hazard-avoidance camera on February 21, 2004, during the rover's 48th martian day, or sol. It dug the trench with its left front wheel the preceding sol. Plans call for Spirit to finish examining the trench on sol 50. Image credit: NASA/JPL. On its 48th sol, ending at 1:16 PM Saturday, PST, Spirit maneuvered its robotic arm successfully within the challengingly tight confines of the trench that the rover had dug into the floor of "Laguna Hollow" the preceding sol. Spirit used the microscopic imager on the arm to take pictures of details in the wall and floor of the trench during the morning. Then Spirit rotated the tool turret at the end of its arm and placed the Moessbauer spectrometer in position to read the mineral composition of the soil on the trench floor. That reading was designed to last about 12 hours, from mid-sol into the martian night. Spirit's panoramic camera and miniature thermal emission spectrometer were also used during the sol for studies of sky and rocks. Spirit has been told to wake up and switch from the Moessbauer spectrometer to alpha particle X-ray spectrometer on the trench floor during the pre-dawn hours of the next sol. Later on sol 49 (which ends at 1:56 p.m. Sunday) and early on sol 50, plans callfor using those spectrometers on the walls of the trench and making additional observations of the "Laguna Hollow" area. Then Spirit is slated to resume its trek toward the rim of the crater nicknamed "Bonneville," now estimated to be about 135 meters (443 feet) northeast of the rover's current location. Supersized Science (Opportunity sol 27) 21 February 2004 On sol 27, ending 12:57 AM Saturday, PST, Opportunity successfully "supersized" the measurements of the "El Capitan" area with the panoramic camera, miniature thermal emission spectrometer, and microscopic imager. The rover team is analyzing "super resolution" and "super spectral" observations from the science instruments and currently locating the best spots to place the rock abrasion tool. Opportunity also drove 33 centimeters (13 inches) closer to "El Capitan" to better poise the robotic arm for use of the

rock abrasion tool sometime over the next four or five sols, which will be the first use of the rock abrasion tool by Opportunity. On sol 28, ending at 1:38 AM Sunday, PST, plans call for Opportunity to take extensive microscopic images of "El Capitan," which is a rich science target because it has multiple layers and varied textures on the upper and lower areas of the rocks, implying multiple changes in the geologic history of this area. The Mars Odyssey orbiter is scheduled to fly over Opportunity during sol 28 with increased data communications capabilities to 256 kilobits per second, which is five times the speed of normal home computer modems. Trench Exam Continues (Spirit sol 49) 22 February 2004 Spirit continued its inspection of the trench dubbed "Road Cut" during the rover's 49th sol, ending at 1:56 PM Sunday, PST. It used three instruments on its robotic arm to examine the subsurface soil exposed by the sol 47 digging of the trench. Before dawn on sol 49, Spirit switched from its Moessbauer spectrometer to its alpha particle X-ray spectrometer for analysis of soil on the trench floor. Later, controllers played "Coisinha do Pai," by Beth Carvalho, as wake-up music. The rover inspected targets on the wall and floor of the trench with its microscope, then placed the Moessbauer spectrometer against a target on the trench wall for identifying the iron-bearing minerals there. The miniature thermal emission spectrometer took remote readings on the rover's wheel tracks in the morning and afternoon. Plans for sol 50 (ending at 2:35 PM Monday, PST) call for finishing inspection of the trench, then resuming the journey toward the rim of a crater dubbed "Bonneville," followed by a longer drive the following sol. Busy Microscope at "El Capitan" (Opportunity sol 28) 22 February 2004 On sol 28, which ended at 1:38 AM Sunday, PST, Opportunity moved its arm repeatedly to make close-up inspections the "El Capitan" part of the street-curb-sized outcrop in the crater where the rover is working. Opportunity took 46 pictures with its microscope, examining several locations on "El Capitan" at a range of focal distances. It also placed its Moessbauer spectrometer and its alpha particle X-ray spectrometer on the rock target to assess what minerals and what elements are present. Controllers chose the song "I am a Rock," performed by Paul Simon and Art Garfunkel, as Opportunity's sol 28 wake-up music. The sol's activities included observations by the miniature thermal emission spectrometer and the panoramic camera, as well as the use of the tools on the arm. The arm's complex maneuvers totaled 25 minutes of actual arm movement. Rover planners' success in accomplishing them drew a round of applause in the Mission Support Area at JPL during the afternoon downlink from Mars. During the martian night, early on sol 29, Opportunity woke up and moved its arm again to switch from the Moessbauer spectrometer to the alpha particle X-ray spectrometer. Additional close-up inspections are planned for later in sol 29, which ends at 2:17 AM Monday. Plans for sol 30 feature the use of the rock abrasion tool to grind through the surface at one target on "El Capitan." Opportunity Gets an Attitude Adjustment (sol 31) 25 February 2004 On sol 31, which ended at 3:36 AM Wednesday, February 25, Opportunity awoke to "Rock Around the Clock" by Bill Haley and his Comets. At 1:00 AM Local Solar Time, Opportunity sent data to Earth via the Mars Global Surveyor orbiter and then sent another whopping 145.6 megabits of data at 3:30 AM Local Solar Time via the Mars Odyssey orbiter. During the morning hours, Opportunity collected data with the alpha particle X-ray spectrometer for five hours and took measurements with its miniature thermal emission spectrometer from inside its newly formed hole that was created on sol 30 by the rock abrasion tool. Later, Opportunity retracted and closed the door of the alpha particle X-ray spectrometer and swapped the Moessbauer spectrometer into the hole made by the abrasion tool for a leisurely 24-hour observation.


NASA's Mars Exploration Rover Opportunity casts a shadow over the El Capitan area that the rover is examining with tools on its robotic arm. Opportunity took this image with its front hazard-avoidance camera on February 23, 2004, during the rover's 29th martian day, or sol. Opportunity used its rock abrasion tool to grind a small hole into Opportunity Ledge later on sol 29 to prepare for using the other tools on its arm to analyze the freshly exposed rock during subsequent sols. Image credit: NASA/JPL. Opportunity also updated its "attitude knowledge," which fine-tunes the rover's information about its exact location and position on Mars. Updating the attitude knowledge allows the rover to more accurately point the high gain antenna toward Earth, which increases the communications capabilities. The attitude adjustment also enables scientists and engineers to point instruments onboard Opportunity more precisely at targets of interest, such as particular rocks and patches of soil. To adjust the attitude knowledge, engineers have the rover turn the panoramic camera to the Sun and watch the Sun travel across the sky for 15 minutes. The rover is then smart enough to take the Sun movement data collected from the panoramic camera to calculate its own location in the universe on Mars. The rover gathers attitude knowledge errors over time as it drives and uses the robotic arm extensively, but it only needs an attitude adjustment about once a week or after driving long distances. Around 12:15 PM Local Solar Time, Opportunity went to sleep to recharge its batteries from its strenuous rock abrasion tool activities on sol 30, but reawakened briefly at 4:00 PM Local Solar Time and again in the evening to send data to Earth via additional overflights by the Mars Global Surveyor and Odyssey orbiters. The plan for sol 32, which ends at 4:15 AM Thursday, February 26, is to take another unique set of Moessbauer measurements to look at the rover-created hole in a different spectrum. The goal is to then crawl slightly forward on sol 33 to position Opportunity to use the rock abrasion tool on the upper target of the El Capitan/McKittrick area. Contacts: Guy Webster Jet Propulsion Laboratory, Pasadena, CA Phone: 818-354-5011 Donald Savage NASA Headquarters, Washington, DC Phone: 202-358-1547

The semi-circular depression on the right side of this microscopic image resulted from Opportunity's first grinding of a rock on Mars. The rock abrasion tool sliced into the surface about 4 millimeters (0.16 inches) deep and ground off a patch 45.5 millimeters (1.8 inches) in diameter on a rock called "McKittrick" during Opportunity's 30th sol on Mars, February 23, 2004. The hole exposed fresh interior material of the rock for close inspection by the rover's microscopic imager and two spectrometers on the robotic arm. Scientists and engineers got a nice bonus in that two spherical features nicknamed "blueberries" were unexpectedly cut in half within this rock. Team members had noticed the blueberries in earlier pictures on other rocks in the outcrop and had wanted to attempt to cut one in half sometime during the future of the mission. As luck would have it, two blueberries were hidden in the depths of "McKittrick." The one blueberry shown in the bottom right of this picture appears to have been scratched by the grinding wheel. The two rectangular boxes in the lower left and upper middle parts of this image are "drop outs," where the data packets inadvertently did not make it back to Earth during the initial communications relay via the Deep Space Network antennas. The missing data packets should be resent to Earth within the next few days. Just above each of the black "drop out" rectangles is another rectangular area filled with a cluster of smaller rectangles in different shades of gray, which are image compression artifacts. Additional articles on this subject are available at: http://www.astrobio.net/news/article840.htm http://www.astrobio.net/news/article841.htm http://www.astrobio.net/news/article842.htm http://www.astrobio.net/news/article843.htm http://www.cnn.com/2004/TECH/space/02/18/mars.rovers.ap/index.html http://www.space.com/missionlaunches/opportunity_dig_040216.html http://www.space.com/missionlaunches/rover_update_040219.html http://www.spacedaily.com/2004/040217212320.bxc9du2w.html http://www.spacedaily.com/2004/040216225851.ic5o7rx6.html http://www.spacedaily.com/2004/040218232317.97qx8w78.html http://www.spacedaily.com/news/mars-mers-04zzj.html http://www.spacedaily.com/news/mars-mers-04zzk.html http://www.spacedaily.com/news/mars-mers-04zzl.html http://www.spacedaily.com/news/mars-mers-04zzm.html http://spaceflightnow.com/mars/mera/040217spirit.html http://spaceflightnow.com/mars/mera/040217trench.html http://spaceflightnow.com/mars/mera/040218spiritsol45.html http://spaceflightnow.com/mars/mera/status.html http://www.universetoday.com/am/publish/opportunity_digs_out_trench.html http://www.universetoday.com/am/publish/opportunity_polished_spheres.html http://www.universetoday.com/am/publish/spirit_could_found_salty_brine.html http://www.universetoday.com/am/publish/opportunity_grinds_away.html


MARS EXPRESS UPDATES ESA releases What do the colors mean? 18 February 2004 http://www.esa.int/export/SPECIALS/Mars_Express/SEMMJQ1PGQD_0.html How do you display a picture of Mars taken with an electronic eye, capable of seeing wavelengths of light that are invisible to humans? Welcome to the wonderful world of 'false' color. The first trio of images from the OMEGA instrument on ESA's Mars Express, released on 23 January 2004, showed some colorful views of Mars' south polar ice cap. That is mainly because two of the images were taken at infrared wavelengths that defy easy translation into color. So, they were displayed in "false" color.

Martian polar ice cap viewed in "normal" visible light. Image credit: ESA/Calvin J. Hamilton.

Martian polar ice cap viewed in false color. OMEGA observed the southern polar cap of Mars on 18 January 2004, as seen on all three bands. The right one represents the visible image, the middle one the CO2 (carbon dioxide) ice and the left one the H2O (water) ice. Image credits: ESA. William Smith, the British "father" of geology, introduced false color to science in the 1800s. He wanted to draw a map of Great Britain to show the different types of rock that could be found across its surface and decided to

color code the rocks. The colors were not intended to represent the true colors of the rocks, but simply to act as a key to identifying them. Political maps of the world also use of false color, clearly showing the boundaries between countries because of the sudden change of color. The OMEGA images here show a visible light image of the martian south pole (far right). This is a traditional combination of red, blue and green wavelengths that all computers and televisions use to make full-color images. The other two images, the middle one showing the distribution of carbon dioxide ice and the left-hand image showing the distribution of water ice are falsely colored. Both ice images are made from infrared radiation reflected by the surface of Mars. Because carbon dioxide and water absorb and reflect characteristically different wavelengths of infrared, OMEGA can identify each chemical compound by looking at the missing parts of the spectra received back from the surface. The astronomers then used false color to show how much ice had been detected at the polar cap. The color scale is blue to red. The bluer the area, the more carbon dioxide ice in the middle image and, in the left-hand image, the more water ice. Red areas are deficient and yellow areas are intermediate zones. Comparing the pictures, the wide yellow expanse on the left-hand image shows that the water ice is more widespread than the carbon dioxide ice. The carbon dioxide ice collects mostly in the blue peak of the middle image. With this early success, OMEGA's Principal Investigator Dr. Jean-Pierre Bibring, Institut d'Astrophysique Spatiale, France, is looking forward to the rest of mission. He says, "Our goal now is to map the whole planet." So, as William Smith's 1815 map of Great Britain helped show the mineral wealth of England, Wales and Scotland, so OMEGA will eventually show the distribution of minerals and rock types across the surface of Mars. Like its predecessor, it too will be presented in glorious 'false' colour. Kasei Vallis 18 February 2004 http://www.esa.int/export/SPECIALS/Mars_Express/SEMMBP1PGQD_0.html

This vertical view shows the mouth of Kasei Vallis, one of the largest outflow channels on Mars, taken by Mars Express. The image was taken by the High Resolution Stereo Camera (HRSC) on board Mars Express during orbit 61 from an altitude of 272 km. The resolution is 12 meters per pixel. The image center is located at 29.8° north and 309° east, the image width is 130 km, North is up.


The part of the outflow channel seen in this image has most probably been carved by glaciers or gigantic water-related outflows known from terrestrial subglacial lakes. The blackish-blue color is related to sediments. The bright streaks oriented NE-SW are related to wind forces. This image shows various details which give an insight into the erosional history of the outflow channel. The image also illustrates how difficult it is to achieve near-true color in images of Mars when atmospheric dust and haze have a major disturbing influence on the scene. Making light work of the dark 24 February 2004 http://www.esa.int/export/SPECIALS/Mars_Express/SEMO0Z1PGQD_0.html It is the start of eclipse season for Mars Express. That means unavoidable passages of the spacecraft through the shadow of Mars, cutting it off from the sunlight that is converted into electrical power by the orbiter's solar arrays. This creates a nervous time for engineers at the European Space Operations Centre (ESOC) in Darmstadt, Germany. Mars Express, however, is making light of this challenging part of the mission. Mars Express orbits the Red Planet in a fixed direction that never changes. As Mars follows its own orbit around the Sun, there are times when Mars Express will be forced into the planet's shadow. When this happens, the spacecraft must rely on battery power alone to keep it alive. "So far things are going very well," says John Reddy of ESA's Mars Express project team.

Artist inpression of Mars Express orbiter making a pass over the Martian surface at a lower point in its orbit. Image credit: ESA. It is viewpoint shared by Rudolf Schmidt, Mars Express Project Manager. He says, "We have a graph predicting what will happen and, so far, the spacecraft has returned data that match our calculations." Mars Express completes one orbit of Mars every 7.5 hours. On 12 February 2004, the spacecraft experienced its first expected eclipse. That one lasted for only a few minutes but, as the days go by, the periods of darkness will rise to a full hour and a half early in March. After this, although the duration of the eclipses will slowly decrease, they will continue for about 150 days. Away from sunlight, the spacecraft gets very cold and so it must be heated, draining the power reserves. When the spacecraft re-emerges, controllers on Earth must align it to recharge the batteries, otherwise all power could be lost during the next eclipse and critical damage could occur. ESOC is in contact with Mars Express for just eight hours every day and so everything must be meticulously planned in advance and the spacecraft carefully programmed with the necessary maneuvers. And what of science during this testing time? At first, it was placed on hold so that the health of the spacecraft could be paramount. Now, with added confidence, science operations are beginning to be performed again.

"It is our intention to perform as much safe science as we can during this period," says Reddy. Although Mars Express will experience other eclipse seasons during its mission, they are not likely to as trying as this one. Additional articles on this subject are available at: http://spaceflightnow.com/mars/marsexpress/040222marscolor.html http://spaceflightnow.com/mars/marsexpress/040222kaseivallis.html MARS GLOBAL SURVEYOR IMAGES NASA/JPL/MSSS release 12-25 February 2004 The following new images taken by the Mars Orbiter Camera (MOC) on the Mars Global Surveyor spacecraft are now available. Crater Floor Bands (Released 12 February 2004) http://jpl.convio.net/site/R?i=URgYWHMFrE1O-3BCLCXxIg Opportunity Site: Before and After (Released 13 February 2004) http://jpl.convio.net/site/R?i=zKcSy6EkZhdO-3BCLCXxIg Happy Valentine's Day 2004 (Released 14 February 2004) http://jpl.convio.net/site/R?i=rvY-LK2p2KlO-3BCLCXxIg Becquerel Beckons (Released 15 February 2004) http://jpl.convio.net/site/R?i=Fh49_2BcPXZO-3BCLCXxIg Complex Wind Streaks (Released 16 February 2004) http://jpl.convio.net/site/R?i=WLebssdEepVO-3BCLCXxIg Third MOC View of Opportunity Landing Site (Released 17 February 2004) http://jpl.convio.net/site/R?i=QAIX84h6oYFO-3BCLCXxIg Gullied Crater Wall (Released 18 February 2004) http://jpl.convio.net/site/R?i=Q6-IQ65RlbNO-3BCLCXxIg Yardangs in Gordii Dorsum Region (Released 19 February 2004 http://jpl.convio.net/site/R?i=vEJCPJun1WhO-3BCLCXxIg Martian Meteor Crater (Released 20 February 2004 http://jpl.convio.net/site/R?i=VtJsvpbee3FO-3BCLCXxIg Small Landslide in Kasei (Released 21 February 2004 http://jpl.convio.net/site/R?i=a1NqQ8gm-ptO-3BCLCXxIg Wind vs. Dust Devil Streaks (Released 22 February 2004 http://jpl.convio.net/site/R?i=3jHqqdNFWJJO-3BCLCXxIg Wind Streak and Crater (Released 23 February 2004 http://jpl.convio.net/site/R?i=TnPfCFbcaRNO-3BCLCXxIg South Polar Layer Remnants (Released 24 February 2004 http://jpl.convio.net/site/R?i=33JSVexYLJ9O-3BCLCXxIg Gullied Martian Slop (Released 25 February 2004 http://jpl.convio.net/site/R?i=o—lbqSsvk9O-3BCLCXxIg All of the Mars Global Surveyor images are archived at http://jpl.convio.net/site/R?i=hL7aJBadsUFO-3BCLCXxIg. 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 16-20 February 2004 THEMIS Images as Art #11 (Released 16 February 2004) http://jpl.convio.net/site/R?i=jjU8ZCw4CyRO-3BCLCXxIg THEMIS Images as Art #12 (Released 17 February 2004) http://jpl.convio.net/site/R?i=X9v3rDIFOrpO-3BCLCXxIg THEMIS Images as Art #13 (Released 18 February 2004) http://jpl.convio.net/site/R?i=pITrtER-mU9O-3BCLCXxIg THEMIS Images as Art #14 (Released 19 February 2004) http://jpl.convio.net/site/R?i=saCnq77LQ3RO-3BCLCXxIg THEMIS Images as Art #15 (Released 20 February 2004) http://jpl.convio.net/site/R?i=5L2OMNAHP1VO-3BCLCXxIg All of the THEMIS images are archived at http://jpl.convio.net/site/R?i=qYpHuPY6cj1O-3BCLCXxIg. 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. ROSETTA UPDATES ESA and NASA releases Rosetta Mated with its Launcher ESA release, 17 February 2004 The spacecraft completed the first few meters of its launch on 16 February 2004 when it was lifted from the bottom of the BAF building and placed on top of its launcher. Rosetta was lifted about 40 meters to the top of the final assembly building before it was moved sideways and lowered onto the Ariane 5 launcher, where it now rests secured by nearly 200 bolts. Spacecraft to Launch, Designed to Harpoon Cosmic Moby Dick NASA/JPL release 04-063, 19 February 2004 Like the massive white whale in Herman Melville's 1851 classic "Moby Dick," comets have long been considered swift, elusive harbingers of change. So it should be of little surprise that one of the best ways for scientists to study the mysteries of comets is to harpoon one. The European Space Agency's Rosetta spacecraft is scheduled to lift off on February 26, 2004, at 2:16 AM EST, from the Kourou spaceport in French Guiana, on the northeastern coast of South America. The launch will be the beginning of a ten-and-a-half year odyssey to comet Churyumov-Gerasimenko that includes flybys of Mars (2007) and the Earth (2005, 2007 and 2009). Among the instruments aboard the Rosetta spacecraft are three instruments funded by NASA and a key component of a fourth. The NASA instruments will examine Churyumov-Gerasimenko from the orbiter. "This comet has only about three-hundred-thousandths the gravity of Earth," said Dr. Claudia Alexander, project scientist for the U.S. role in the mission, from NASA's Jet Propulsion Laboratory (JPL), Pasadena, CA. "The Rosetta spacecraft will be able to make observations from as close as 2 kilometers (1.2 miles). The data from our state-of-the-art instruments will be amazing," she added. Rosetta will reach Churyumov-Gerasimenko, a four-kilometer (2.5-mile) diameter comet, in May 2014. When this rendezvous occurs, Churyumov-Gerasimenko will be about three times as far from the sun as the Earth is. Over the next 18 months Rosetta will study how the comet changes as it moves closer to the sun. In November 2014, Rosetta will drop its experiment-laden, harpoon-firing lander on Churyumov-Gerasimenko's icy nucleus.

"What you have to understand is that comets are primordial remnants of the early solar system," explained Dr. Paul Weissman of JPL. "They are the keys to understanding the way the whole solar system, the Earth, and how even we came into being. And with Rosetta we will be able to observe, study and analyze this primordial material up close for more than a year," he said. JPL supplied the Microwave Instrument for Rosetta Orbiter, the first of its type on any interplanetary mission. This instrument can reveal the abundances of selected gases, their temperatures, the speed at which they are coming off the nucleus, and the temperature of the nucleus. Scientists will use it to monitor changes in how vapors are released from the nucleus as the coma and tail grow. They will be studying water, carbon monoxide, ammonia and methanol, four of the most abundant gases from comets. Dr. Samuel Gulkis of JPL's Earth and Space Sciences Division is principal investigator. The Southwest Research Institute, based in San Antonio, supplied two NASA instruments for Rosetta. One is an imaging telescope/spectrometer capable of analyzing the composition both of gases released by the comet and of the comet's surface. A goal of scientists using the instrument is to learn about the temperatures at which comets form and evolve, by determining the relative abundance of noble gases, such as helium, neon and argon. Principal investigator for the ultraviolet instrument is Dr. Alan Stern of the institute's Space Studies Department in Bolder, CO. Dr. James Burch, of the Institute's Instrumentation and Space Research Division, San Antonio, is principal investigator for Rosetta's Ion and Electron Spectrometer. This device will measure the environment of charged particles surrounding comet Churyumov-Gerasimenko. It will also study the interaction between that environment and the solar wind of charged particles speeding outward from the sun. Key electronics for a fourth instrument, the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis, have been supplied by Lockheed Martin Advanced Technology Center, Palo Alto, CA. This instrument will examine gases surrounding the comet. JPL, a division of the California Institute of Technology in Pasadena, manages the microwave instrument for NASA's Office of Space Science, Washington, DC. Once a Myth, Now an Object of Study ESA release 05-2004, 23 February 2004 On 26 February, Rosetta will be setting off on its long journey through our solar system to meet up with Comet Churyumov-Gerasimenko. It will take the European Space Agency (ESA) space probe ten years to reach its destination. The comet, which moves in an elliptical orbit around the Sun, will at rendezvous be some 675 million kilometers from the Sun, near the point in its orbit farthest from the Sun. The meeting point was not chosen at random: at this point the comet is still barely active, it is still in fact a frozen lump of ice and interplanetary dust, in all probability the matter from which our solar system emerged four and a half billion years ago. Rosetta's job is to find out more about these strange bodies that travel through our solar system. As it moves on, the comet will begin to change. As it approaches the Sun, it will—like all comets—become active: in the warmth of the Sun's rays, the ices evaporate, tearing small dust particles from the surface. This produces the comet head (the coma) and tail during solar flyby skims several meters of matter off the comet's surface. In the case of a small comet like Churyumov-Gerasimenko, the shrinkage is a good 1% each time round. As it flies past the Sun every 6.6 years it can look forward to a short future, especially on a cosmic timescale. Comets, a mystical view Visible cometary phenomena have fascinated human beings from time immemorial—and frightened them too. Even today mystical explanations prevail among some of the Earth's peoples. The Andaman islanders, a primitive people living in the Gulf of Bengal, see comets as burning torches hurled into the air by forest spirits—the more easily to detect humans foolish enough to stay out at night. For some Australian aborigines, comets are flaming sticks ridden by mighty shamans. Efforts to provide a scientific explanation of the "cometa aster" ("hairy star") phenomenon stretch back to ancient times. A widely held view was that comets were in some way connected with processes at work in the


atmosphere. In Meteorologica, Aristotle (384-322 BC) described how inflammable gases escape from clefts in rocks, collect in the upper layers of the sub-lunar world ("world under the Moon") and ignite. Rapid release of such gases produced a shooting star; when let out slowly, they gave rise to a comet. That was Aristotle's best shot—and he was well aware of his limited insight into the question. As he himself acknowledged, "As we have no demonstrable basis for assertions about comets, I have to settle for an interpretation that does not conflict with established truths." Admittedly such truths were thin on the ground at the time. Comets, something of a disaster As the centuries unfolded, what could be called the opposite view—that the comets were responsible for intense heat spells—also gained a considerable audience, though there was just as little truth in it. The natural philosophers went one further. They said comets lead to heat, heat to storms and storms to natural disasters. Pliny the Elder for example (born circa 23 AD) listed twelve cometary phenomena according to their external appearances. And he assigned one natural disaster to each class. The Christian Middle Ages no longer saw cometary phenomena as the blind raging of an even blinder nature, preferring to interpret them as signs from God. Theologians such as Saint Hildegard of Bingen (1098-1179) and Albert Magnus (1200-1280) cited holy scripture. The Book of Jeremiah for example (1:11,12), in which God caused a fearsome "rod of an almond tree" to appear in the sky, a symbol of the prophet's empowerment. Or again Luke 21:11, "And great earthquakes shall be in divers places, and famines, and pestilences; and fearful sights and great signs shall there be from heaven." In 1066, Halley's Comet appeared to many as a harbinger of the Norman conquest of Britain, so vividly portrayed in the Bayeux tapestry, with its scenes from the Battle of Hastings. The decisive step towards overturning the view that comets are atmospheric phenomena was taken in 1577 by Danish astronomer, Tycho Brahe. For two and a half months he observed from his observatory in Uranienburg the progress of a comet across the heavens. Relying on the phenomenon of the daily parallax—an apparent "shuddering" motion of heavenly bodies in fact attributable to the observer's position on the revolving Earth—he was able to establish that the comet had to be located beyond the lunar orbit. Halley discovers an elliptical orbit The scientific description of comets took another major step forward in 1705 thanks to the work of the British astronomer and physicist, Edmond Halley, a friend and patron of Isaac Newton. Investigating recorded comet measurements, he observed that the orbits of a number of bright comets were very similar; his own calculation of the orbit of a comet observed in 1682 coincided with the data recorded by Johannes Kepler in 1607 and by Apianus in 1531. He concluded that various comet observations were attributable to one and the same comet. Halley was proved right when in December 1758, the comet whose return he had predicted, thenceforth named after him, did indeed make a repeat appearance. This confirmed his theory that apparently parabolic comet orbits were in fact "simply" sections of one enormous elliptical orbit. Since then observations recorded in China in 240 BC have been identified as relating to a sighting of Halley's comet, the oldest known document dealing with this phenomenon. What was described in the Bible as a sign from God was seen by Fred Hoyle, the British astrophysicist, as a possible explanation for the great hiatal breaks in history. He took the view that such extraordinary developments as the extinction of the mammoth were attributable to strikes by comet fragments. His views incorporated the theory advanced by British astronomers Victor Clube and Bill Napier in 1982 that a giant comet was trapped by our solar system 15,000 years ago. With the return of that comet every 1600 years, the accompanying debris—so the argument goes—prompted some of the world's great turning points. This might also be an explanation for such legends as the Flood. A lump of icy sludge So what does the actual nucleus of a comet look like? One answer was supplied by the Giotto space probe in a mission masterminded by ESA. The probe was named after the major Italian painter Giotto di Bondone, who, in the early 14th century, portrayed a comet in his fresco in the Scrovegni Chapel

in Padua. On 14 March 1986, the probe succeeded in taking 100-metre-resolution pictures of the nucleus of Halley's Comet from only 600 kilometers away. In the words of Uwe Keller, "The mission forced us to revisit our long-standing image of a comet nucleus as a 'dirty snowball'. The pictures showed that it was more like a lump of icy sludge. The solid part of the nucleus is much larger than the icy part." Bur hardly had Giotto trained its electronic eye on the heavenly body than the photo opportunity was already over; a dust particle measuring about a millimeter hit the probe. As the velocity differential between probe and comet was at that point 68.4 km per second, the force of the involuntary encounter was enough to put paid to any further snapshots. All the same, despite the damage to the camera, it proved possible to go on with the mission. Following two periods of "hibernation", Giotto achieved a successful flyby of the Grigg-Skjellerup comet on 10 July 1992. Rosetta should now bring us entirely new knowledge about comet nuclei. It will orbit the comet and deposit a small lander probe on its surface. So for the first time in history a comet traveling sunwards will be investigated from close quarters. Rosetta Ready for Launch 25 February 2004 http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=34761 On the evening of 23 February the final activity on the Rosetta spacecraft, the arming of the Lander harpoons and removal of the harpoon protective covers, took place. It was a delicate operation involving one team member being placed well inside the fairing on what is called a diving board to perform the operation.

Left: a technician works inside the fairing to remove the protective covers on the harpoons. Right: launcher arriving at the launch pad. Image credits: ESA. At 15:30 local time on 24 February the Ariane 5 rocket moved along the 2.8 km rail line from the Final Assembly Building to the launch zone. Ariane Flight 158 is scheduled to launch at 07:36 and 49 seconds UT on 26 February 2004. On launch the rocket will undergo booster separation and burnout of the central core stage as in other Ariane 5 launches. The Upper Stage will then enter a long ballistic phase, followed by ignition 2 hours after launch. 14 minutes later Rosetta will separate and enter an Earth escape trajectory that will set it on its long course to Comet Churyumov-Gerasimenko. For further information on Rosetta see http://www.esa.int/rosetta. For more on ESA Science missions see http://www.esa.int/science. Contacts: ESA, Media Relations Service Phone: 33(0)1.53.69.7155 Fax: 33(0)1.53.69.7690 Donald Savage NASA Headquarters, Washington, DC Phone: 202-358-1727 D. C. Agle Jet Propulsion Laboratory, Pasadena, CA Phone: 818-393-9011


Additional articles on this subject are available at: http://www.astrobio.net/news/article836.htm http://www.spacedaily.com/news/comet-04c.html http://spaceflightnow.com/ariane/v158/040216sophisticate.html http://spaceflightnow.com/ariane/v158/status.html STARDUST STATUS REPORT NASA/JPL release 20 February 2004 The Stardust team had two periods of communications with the spacecraft in the past week. Telemetry relayed from the spacecraft indicates it remains in very good shape. 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://jpl.convio.net/site/R?i=eY7KdkmJwYJO-3BCLCXxIg.

Abstracts of the Stardust science results from the Comet Wild 2 encounter are now available at ftp://www.lpi.usra.edu/pub/outgoing/lpsc2004/full07.pdf (Adobe Acrobat reader required). The papers will be presented at the Lunar and Planetary Science Conference being held at League City in Texas from March 15-19, 2004. For more information on the Stardust mission—the first ever comet sample-return mission—please visit the Stardust home page at http://jpl.convio.net/site/R?i=8tVworpCtnhO-3BCLCXxIg. End Marsbugs, Volume 11, Number 9.

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