Marsbugs: The Electronic Astrobiology NewsletterVolume 11, Number 15, 6 April 2004

Editor/Publisher: David J. Thomas, Ph.D., Science Division, Lyon College, Batesville, Arkansas 72503-2317, USA. dthomas@lyon.edu

Marsbugs is published on a weekly to monthly basis as warranted by the number of articles and announcements. Copyright of this compilation exists with the editor, except for specific articles, in which instance copyright exists with the author/authors. 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

Page 1 HUNT FOR EXTRASOLAR EARTH-LIKE PLANETS INTENSIFIESRoyal Astronomical Society press notice PN04-14

Page 2 MOON-TO-MARS FEASIBLE, EXPERTS SAY, BUT POLITICS, LACK OF INDUSTRY COOPERATION COULD JEOPARDIZE VISIONBy Leonard David

Page 2 CAN INTELLIGENT LIFE THRIVE IN CLOSE QUARTERS? AN INTERVIEW WITH CHRISTOPHER CHYBABy Henry Bortman

Page 3 LIFE BENEATH THE ICE IN THE OUTER SOLAR SYSTEM?Royal Astronomical Society press notice PN04-10

Page 4 TITAN'S LAPPING OIL WAVESBased on a Royal Astronomical Society report

Page 5 HUMAN EXPLORATION OF THE MOON AND MARSRoyal Astronomical Society press notice PN04-09

Page 5 METHANE DETECTION POINTS TO LIFE ON MARSBy Robert Zubrin

Page 6 MOLECULAR MIDWIVES HOLD CLUES TO THE ORIGIN OF LIFEFrom SpaceDaily

Page 7 PLANETARY SYSTEMS WITH HABITABLE EARTHS?Royal Astronomical Society press notice PN04-13

Page 8 SPACE DEFINES MARS SAMPLE RETURN MISSIONEADS Astrium press release

Page 8 CHEAP COMMUNICATION SCHEMES FOR ETBy Seth Shostak

Page 8 ASHES OF THE PHOENIXBy Peter Backus

Page 9 EUROPA: LIVING WORLD OR FROZEN WASTELAND? AN INTERVIEW WITH CHRISTOPHER CHYBABy Henry Bortman

Announcements

Page 10 NEW ADDITIONS TO THE ASTROBIOLOGY INDEXBy David J. Thomas

Mission Reports

Page 11 CASSINI SIGNIFICANT EVENTSNASA/JPL release

Page 12 MARS EXPLORATION ROVERS STATUS REPORTSNASA/JPL releases

Page 14 MARS EXPRESS: COMMISSIONING ALMOST COMPLETEESA release

Page 14 MARS GLOBAL SURVEYOR IMAGESNASA/JPL/MSSS release

HUNT FOR EXTRASOLAR EARTH-LIKE PLANETS INTENSIFIESRoyal Astronomical Society press notice PN04-14

23 March 2004

An international group of astronomers led by Dr. Jean-Philippe Beaulieu (Institut d'Astrophysique de Paris) and Dr. Martin Dominik (University of St. Andrews) are about to continue their hunt for extrasolar planets with an enhanced world-wide telescope network in May this year. They are hoping to secure the firm evidence for the existence of Earth-mass planets orbiting stars other than the Sun, which has so far eluded astronomers. Dr. Dominik will describe the project, known as PLANET (Probing Lensing Anomalies NETwork), at the Royal Astronomical Society National Astronomy Meeting at the Open University on Thursday 1 April.

Recent scientific research shows that the existence of life on other worlds is a realistic scenario. By measuring the periodic variation of the radial velocity of stars induced by an orbiting planet, astronomers have so far detected over 100 planets but all of them are large, similar to Jupiter and Saturn in our solar system, and environmental conditions suitable for life do not exist on such gas giant planets.

The only technique currently capable of detecting planets similar to Earth makes use of the phenomenon called "galactic microlensing". In a

microlensing event, a star temporarily appears brighter than it really is because another astronomical body is passing between it and observers on Earth; the gravitational field of the intervening object affects the starlight in a way similar to a lens.

If the intervening object is a star, it causes a characteristic signal that lasts about a month. Any planets orbiting this star can produce significant deviations in the signal, lasting days for giant planets down to hours for Earth-mass planets. The probability of this happening is between 1.5% and 20% depending on the mass of the planet.

The PLANET campaign performs nearly-continuous round-the-clock high-precision monitoring of ongoing microlensing events, sampling the lightcurve at intervals that may be as little as few minutes with a world-wide network of telescopes. The backbone of the network is formed by the Danish 1.54-m telescope at the European Southern Observatory at La Silla (Chile), the Canopus Observatory 1.0-m telescope (Tasmania, Australia), the Perth 0.6-m telescope (Western Australia), and the Boyden 1.5-m telescope (South Africa), which is supplemented by some other telescopes. PLANET will share information and some resources with the microlensing campaign performed with RoboNet, a UK robotic telescope network comprised of the Liverpool 2.0-m (Canary Islands, Spain) and the two Faulkes 2.0-m telescopes (Hawaii and Australia).

Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 15, 6 April 2004

From the 500-700 microlensing events announced annually by the survey campaigns OGLE and MOA that monitor tens of millions of stars on a daily basis, PLANET focuses on up to 75 events that are selected as most suitable candidates for the detection of planets around the intervening lens star. "If 20% of these stars are surrounded by planets, 10-15 giant planets and 1 or 2 terrestrial planets are expected to reveal their existence over three years of operation", Dr. Dominik said.

While PLANET might detect a second Earth, its typical expected distance would be 20,000 light years—much too far to think of establishing any contact!

Contacts:Dr. Martin Dominik University of St. Andrews School of Physics & Astronomy North Haugh, St. Andrews KY16 9SS United Kingdom Phone: (+44)-(0)1334-463066 Fax: (+44)-(0)1334-463104 E-mail: md35@st-andrews.ac.uk

Dr. Jean-Philippe Beaulieu Institut d'Astrophysique de Paris 98bis Boulevard d'Arago 75014 Paris France Phone: +33-1-44-328119 Fax: +33-1-44-328001 E-mail: beaulieu@iap.fr

Read the original news release at http://www.ras.org.uk/html/press/pn0414ras.html.

Additional articles on this subject are available at:http://www.spacedaily.com/news/extrasolar-04j.htmlhttp://spaceflightnow.com/news/n0403/31planets/

MOON-TO-MARS FEASIBLE, EXPERTS SAY, BUT POLITICS, LACK OF INDUSTRY COOPERATION COULD JEOPARDIZE VISIONBy Leonard DavidFrom Space.com

30 March 2004

President George W. Bush’s vision to send robotic and human explorers back to the Moon, on to Mars and beyond can be made affordable and sustainable. But turning rhetoric into reality will require drawing upon the talents of civil and military abilities, as well as industrial prowess, policy and space technologists participating in the 20th annual meeting of the National Space Symposium said Tuesday.

Participating in the panel, "The New NASA Vision—How We Got Here. What It Means," Bretton Alexander, Senior Policy Analyst at the White House Office of Science and Technology Policy, outlined President Bush’s January 14th marching orders for NASA. Alexander said the tragic loss of the shuttle Columbia early last year created a crisis in the civilian space sector, compounded by the lack of a compelling vision for the nation’s human space flight program. There has been a 30-year national debate as to the nation’s space goals, he said, which President Bush has ended by setting the country on a bold course for the 21st century.

James Kennedy, Director of NASA’s John F. Kennedy Space Center in Florida urged that the Bush plan for space must be more than a partisan, one-President commitment.

"I personally think it’s time, after Congress has spoken on this subject... it’ll be time for this to be no longer the President’s vision. This should be de-politicized. It should be our national vision of space exploration," Kennedy said. "I hope that we adopt that as our own personal vision."

Read the full article at http://www.space.com/news/nss_moonmars_040330.html.

CAN INTELLIGENT LIFE THRIVE IN CLOSE QUARTERS? AN INTERVIEW WITH CHRISTOPHER CHYBABy Henry BortmanFrom Astrobiology Magazine

31 March 2004

Christopher Chyba is the principal investigator for the SETI Institute lead team of the NASA Astrobiology Institute. Chyba formerly headed the SETI Institute's Center for the Study of Life in the Universe. His NAI team is pursuing a wide range of research activities, looking at both life's beginnings on Earth and the possibility of life on other worlds. One of his team's research projects will explore a question critical to the search for extraterrestrial intelligence. Can planets orbiting red dwarf M-type stars support life—perhaps even intelligent life? Astrobiology Magazine's managing editor Henry Bortman recently spoke with Chyba about Tarter's, Mancinelli's, and Backus's research.

SETI's Jill Tarter (left), Peter Backus (center), and Rocco Mancinelli (right). Image credit: SETI Institute.

Astrobiology Magazine: Jill Tarter and Peter Backus, and microbiologist Rocco Mancinelli, all of whom are with the SETI Institute, are involved in the search for extraterrestrial intelligence. Their contribution to your NAI team's research will be to consider the habitability of M-class red dwarf stars, their potential as SETI targets.

At a forum last winter, Frank Drake explained his famous Drake Equation, which calculates the likelihood that there are other intelligent species in our galaxy. One of the equation's factors, R*, has to do with the rate at which the galaxy produces stars that provide environments capable of supporting

intelligent life. He said that a major question in determining this factor had to do with the habitability of M-class stars. Of the 20 or so stars produced in the galaxy each year, 15 of them are dim M dwarfs. And so, if it turns out that planets around M dwarfs could support intelligent life, there would be many more stars on the SETI target list than if M dwarfs were excluded. Is that the question that Jill, Rocco and Peter are hoping to answer?

Christopher Chyba: You're right on target. We're going to have a series of workshops that involve project co-investigators and other people who are experts in stellar evolution—and also biologists, microbiologists, and it's likely we'll bring others in—to look at this question of the habitability of worlds around M stars.

There are two reasons why that question is tough. One's mostly a red herring, and the other is more significant. For a planet to be in the so-called habitable zone of an M star, it has to be close enough to have liquid water. For a red dwarf, that means it has to be real close, because the star is dim. But that also means that it's going to be close enough that on a geologically short time span it's going to be spin-locked, with the same side of the planet always facing the star, the way the moon is with the Earth.

There was concern for a while—this is featured in Rare Earth—that that would mean that all of the planet's atmosphere would freeze out on its dark side, and that would be that. But, in fact, if you do the greenhouse simulations—Joshi et al. published these results in 1997— for those kinds of worlds, you find that you need only around a tenth of a bar of carbon dioxide to give you a thick enough atmosphere, enough greenhouse effect, that you redistribute the heat so that your atmosphere doesn't freeze out. That's a lot more carbon dioxide than we have on Earth, but well within the range of what's plausible.

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Of the 20 or so stars produced in the galaxy each year, 15 of them are dim M dwarfs. Image credit: NASA.

Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 15, 6 April 2004

If you get up into the range of a bar or so of carbon dioxide, not only does your atmosphere not freeze out, but you stay warm on both sides of the planet, so you have liquid water potentially all over the planet. You have no guarantees that a planet around an M dwarf will have that much carbon dioxide. But you don't have any guarantee of having the atmosphere you want on a planet around a G-class (sun-like) star, either. So I don't think that's a decisive problem, although we will certainly revisit that.

The other issue, though, has to do with flaring from those stars. Its radiation environment might be too harsh for life on planets around M stars, although papers published as early as 1991 called this into question. And that's something that we need a much better understanding of, astrophysically and atmospherically. We also want to have biologists in the picture so that we can get a better handle on just how challenging the radiation and ultraviolet environments would be either for microscopic life or for more sophisticated forms of life. And that will ultimately lead to an operational decision about whether or not we expand the list of target stars for our SETI search to include M stars. Remember, as Frank said, these are 75 percent of the nearby stars. So answering this question will have a huge impact on our search strategy.

Left: Frank Drake, whose famous Drake Equation calculates the likelihood that there are other intelligent species in our galaxy. Right: Christopher Chyba, principal investigator for NASA Astrobiology Institute's SETI lead team. Image credit: SETI Institute.

AM: I'm surprised that NASA is funding a research project whose focus is the search for extraterrestrial intelligence. I was under the impression that NASA was forbidden by Congress from funding SETI.

CC: No, that's no longer the case. Let me clarify, and then explain what's changed, because this is something that has often caused confusion. There was never any prohibition against NASA funding research projects out of the SETI Institute. What the prohibition was understood to be—really, misunderstood to be—was a prohibition against funding SETI science, whether it was the SETI Institute, or the Harvard SETI project, or the Berkeley SETI project, or any other SETI project. The interpretation was that they were not permitted to fund that entire area of science.

What was really the case was that Congress zeroed SETI research out of the NASA budget in '93—but that was a one-time elimination from the budget. There wasn't any language saying, "You shall never fund SETI research ever again." But it was interpreted that way, and I understand that. A government agency thinks it gets a directive from Congress and it wants to be faithful to that.

What's changed is that the sense of Congress is different now. And you can see that back to at least 2001, when the Aeronautics and Space Subcommittee of the House Science Committee held a hearing on life in the universe, and they had four or five people testifying, including myself. I testified mostly about astrobiology and how SETI is a natural component of the continuum of questions asked in astrobiology. And there was a clear sense of the committee at that time, at the hearing, that SETI was part of astrobiology. In fact, this led to a statement that NASA would consider SETI science projects equally under peer review with other projects that fit within astrobiology. That is to say, NASA could make these decisions on the basis of peer review, rather than on the basis of some extra-scientific reason. That was, after all, reflected in the new Astrobiology Roadmap, which for the first time includes SETI as a component of astrobiology. And the funding for a SETI project within this proposal is just a kind of natural outcome of that process.

But you're right, in the sense that that's a shift in at least perception in the last few years. And I think a few things have happened. One is that, while it's still entirely possible that there's no life anywhere else in the known universe

other than Earth—we don't have definite evidence that there's life anywhere else—there has been a whole series of discoveries that make it seem more plausible that there's extraterrestrial life. So I think that's the intellectual context. And there's a lot of enthusiasm in Congress now.

The other thing to mention is that there is a standing committee of the National Academy of Sciences National Research Council, the Committee on the Origin and Evolution of Life, which was asked by Congress to do a report on astrobiology, and in particular to assess the role of SETI in astrobiology. And that committee's report is effusive in its praise for SETI and, to be frank, the SETI Institute, so I think that played a role, too, because that represented outside support. So I think a lot of things came together in the space of the last few years.

Read the original article at http://www.astrobio.net/news/article901.html.

LIFE BENEATH THE ICE IN THE OUTER SOLAR SYSTEM?Royal Astronomical Society press notice PN04-10

31 March 2004

At present, we know of no worlds beyond our Earth where life exists. However, primitive organisms on our planet have evolved and adapted over billions of years, colonizing the most inhospitable places. Since life seems to gain a foothold in the most hostile environments, it seems distinctly possible that living organisms could exist in ice-covered oceans on worlds far from the Sun, according to Dr. David Rothery (Open University), who will be speaking today at the RAS National Astronomy Meeting in Milton Keynes.

This image of Jupiter's icy satellite Europa shows surface features such as domes and ridges, as well as a region of disrupted terrain including crustal plates which are thought to have broken apart and "rafted" into new positions. The image covers an area of Europa's surface about 250 by 200 kilometer (km) and is centered at 10 degrees latitude, 271 degrees longitude. The color information allows the surface to be divided into three distinct spectral units. The bright white areas are ejecta rays from the relatively young crater Pwyll, which is located about 1000 km to the south (bottom) of this image. These patchy deposits appear to be superposed on other areas of the surface, and thus are thought to be the youngest features present. Also visible are reddish areas which correspond to locations where non-ice components are present. This coloring can be seen along the ridges, in the region of disrupted terrain in the center of the image, and near the dome-like features where the surface may have been thermally altered. Thus, areas associated with internal geologic activity appear reddish. The third distinct color unit is bright blue, and corresponds to the relatively old icy plains. Image credit: NASA/University of Arizona.

Europa is the innermost of Jupiter's large icy satellites. It is slightly smaller than our own Moon, but its rocky interior is hidden beneath a 100 km blanket of ice. There has been much speculation as to whether the ice remains solid

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right down to the moon's rocky interior, or whether it consists of a thinner ice sheet floating on an ocean of water. Data from NASA's Galileo spacecraft, which orbited Jupiter from 1995 until 2003, provided detailed insights into Europa's structure that will not be surpassed until the arrival of NASA's Jupiter Icy Moons Orbiter (which may not be until 2023).

The high-resolution Galileo images and other data revolutionized our knowledge of Europa's surface and interior structure, making it seem more likely that the ice is (at least at some times and in some places) relatively thin (much less than 10 km) and overlying a liquid water ocean. The images showed localized areas of "melt-through" demonstrated by "chaos" regions, where detached rafts of the icy shell can be seen dispersed in a now-refrozen matrix. The cause of melt-through is likely to be tidal heating, which is especially strong within Europa because it orbits within the immense gravity of Jupiter and experiences competing tidal pulls from the large, neighboring moons, Io and Ganymede. This process also powers the widespread volcanic eruptions on Io.

These artist's drawings depict two proposed models of the subsurface structure of the Jovian moon, Europa. Geologic features on the surface, imaged by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft might be explained either by the existence of a warm, convecting ice layer, located several kilometers below a cold, brittle surface ice crust (top model), or by a layer of liquid water with a possible depth of more than 100 kilometers(bottom model). If a 100 kilometer (60 mile) deep ocean existed below a 15 kilometer (10 mile) thick Europan ice crust, it would be 10 times deeper than any ocean on Earth and would contain twice as much water as Earth's oceans and rivers combined. Unlike the Earth, magnesium sulfate might be a major salt component of Europa's water or ice, while the Earth's oceans are salty due to sodium chloride (common salt). Image credit: NASA/SETI Institute.

There may be occasional volcanic eruptions onto Europa's ocean floor—rather like a less active, ice-covered version of Io—or, more likely, hot springs where chemically-enriched water heated by passage through the rock re-emerges on the ocean floor. This sort of environment is currently regarded as the most likely place for life on Earth to have begun, and life on Europa could have arisen in just the same way. If so, life could survive there today,

supported by chemical energy in the same way that the hydrothermal vents on Earth's ocean floors support ecosystems that do not depend on sunlight.

"Episodes of tidal heating in some of the Solar System's other icy bodies could equally well have given rise to life, even in such remote bodies as the newly discovered, remote planetoid Sedna if, as has been suggested, it has a satellite with which to interact tidally," said Dr. Rothery. "However, only in the case of Europa, and perhaps a few other satellites of the giant planets, does it seem plausible that life could flourish in the long term."

Contact:Dr. David A. RotheryDepartment of Earth SciencesThe Open UniversityMilton Keynes MK7 6AAPhone: +44 (0)1908 652124Fax: +44 (0)1908 655151Mobile: +44 (0)7986-260258 E-mail: d.a.rothery@open.ac.uk

Further information and images can be found on the web at the NASA Galileo Web site:http://galileo.jpl.nasa.gov/http://galileo.jpl.nasa.gov/images/europa/eurimages.htmlhttp://galileo.jpl.nasa.gov/images/europa/eurchaotic.html

Read the original news release at http://www.ras.org.uk/html/press/pn0410ras.html.

Additional articles on this subject are available at:http://www.spacedaily.com/news/outerplanets-04c.htmlhttp://spaceflightnow.com/news/n0403/30europalife/http://www.universetoday.com/am/publish/is_life_europa.html

TITAN'S LAPPING OIL WAVESBased on a Royal Astronomical Society report From Astrobiology Magazine

31 March 2004

When the European Huygens probe on the Cassini space mission parachutes down through the opaque smoggy atmosphere of Saturn's moon Titan early next year, it may find itself splashing into a sea of liquid hydrocarbons. In what is probably the first piece of "extraterrestrial oceanography" ever carried out, Dr. Nadeem Ghafoor of Surrey Satellite Technology and Professor John Zarnecki of the Open University, with Drs. Meric Srokecz and Peter Challenor of the Southampton Oceanography Centre, calculated how any seas on Titan would compare with Earth's oceans. Their results predict that waves driven by the wind would be up to 7 times higher but would move more slowly and be much farther apart. The team worked with a computer simulation, or "model", that predicts how wind-driven waves on the surface of the sea are generated on Earth, but they changed all the basic inputs, such as the local gravity, and the properties of the liquid, to values they might expect on Titan.

Arguments about the nature of Titan's surface have raged for a number of years. Following the flyby of the Voyager 1 spacecraft in 1980, some researchers suggested that Titan's concealed surface might be at least partly covered by a sea of liquid methane and ethane. But there are several other hypotheses, ranging from a hard icy surface at one extreme to a near-global hydrocarbon ocean at the other. Other variants include the notion of hydrocarbon "sludge" overlying an icy surface. Planetary scientists hope that the Cassini/Huygens mission will provide an answer to this question, with observations from Cassini during several flybys of Titan and from Huygens, which will land (or splash) on 14 January 2005.

The idea that Titan has significant bodies of surface liquid has recently been reinforced by the announcement that radar reflections from Titan have been detected using the giant Arecibo radio dish in Puerto Rico. Importantly, the returned signals in 12 out the 16 attempts made contained reflections of the kind expected from a polished surface, like a mirror. (This is similar to seeing a blinding patch of light on the surface of the sea where the Sun is being reflected.) The radar researchers concluded that 75% of Titan's surface may be covered by "open bodies of liquid hydrocarbons"—in other words, seas.

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The exact nature of the reflected radar signal can be used to determine how smooth or choppy the liquid surface is. This interpretation says that the slope of the waves is typically less than 4 degrees, which is consistent with the predictions of the British scientists, who showed that the maximum possible slope of waves generated by wind speeds up to 7 mph would be 11 degrees.

"Hopefully ESA's Huygens probe will end the speculation" says Dr Ghafoor. "Not only will this be by far the most remote soft landing of a spacecraft ever attempted but Huygens might become the first extraterrestrial boat if it does indeed land on a hydrocarbon lake or sea."

Huygens parachutes onto Titan. ESA's Huygens probe descends through Titan's mysterious atmosphere to unveil the hidden surface (artist's impression). Image credit: ESA.

Although not designed specifically to survive landing or to float, the chances it will do so are reasonable. However, the link back to Earth from Huygens via Cassini, which will be flying past Titan and acting as a relay, will only last for a maximum of 2 hours. During this time, if the probe is floating on a sea, one of the 6 instruments Huygens is carrying, the Surface Science Package experiment, which is led by John Zarnecki, will be making oceanography measurements. Among the 9 sensors that it carries are ones that will measure the height and frequency of the waves and also the depth of the sea using sonar. It will also attempt to determine the composition of the sea.

What would the sea look like?

"Huygens does carry a camera so it is possible we shall have some direct images," says Professor Zarnecki, "but let's try to imagine that we are sitting onboard the probe after it has landed in a Titan ocean. What would we see? Well, the waves would be more widely dispersed than on Earth but they will be very much higher—mostly as a result of the fact that Titan gravity is only about 15% of that on Earth. So the surface around us would probably appear flat and deceptively calm, but in the distance we might see a rather tall, slow-moving wave advancing towards us—a wave that could overwhelm or sink us."

Read the original article at http://www.astrobio.net/news/article902.html.

Additional articles on this subject are available at:http://www.astrobio.net/news/article904.htmlhttp://www.spacedaily.com/news/saturn-titan-04e.htmlhttp://www.universetoday.com/am/publish/new_images_titan_vlt.html

HUMAN EXPLORATION OF THE MOON AND MARSRoyal Astronomical Society press notice PN04-09

31 March 2004

These are exciting times for space exploration. For the first time in a generation, human missions beyond Earth orbit are being seriously considered by space agencies on both sides of the Atlantic. Europe has initiated the

Aurora program, with the ultimate aim of landing people on Mars by 2033, while the US has recently redirected its human space activities towards a return to the Moon.

On Friday 2 April, Dr. Ian Crawford, a planetary scientist based at Birkbeck College, London, will be explaining to the RAS National Astronomy Meeting, held at the Open University in Milton Keynes, that there are indeed strong scientific reasons for sending people back to the Moon and on to Mars. These arguments are further developed in an article published in the April issue of the Royal Astronomical Society's journal Astronomy & Geophysics, which is timed to coincide with the meeting.

"The reasons for exploring the Moon and Mars are both very strong, but rather different," said Dr. Crawford. "The importance of the Moon results from its extremely ancient surface, which preserves a record of early Solar System history that is not preserved anywhere else. On the other hand, the main reason for wanting to explore Mars is to search for past or present life on the planet, which is probably one of the most important scientific questions of our time."

Given that strong scientific cases exist for a human return to the Moon and for sending people on to Mars, Dr. Crawford argues that the two should be combined in a self-consistent, international strategy for Solar System exploration. Europe's Aurora program could be a major part of such a strategy. The UK will shortly have to decide whether or not to participate in the human spaceflight aspects of Aurora, and Dr. Crawford believes that we should seize this unique opportunity to play a leading role in these exciting endeavors.

Given the difficulties of sending people to Mars, Dr. Crawford argues that it would be wiser, initially, to concentrate human spaceflight activities on the Moon. This would not only teach us much about the Moon and its history, but also help pave the way for later human missions to Mars by developing the necessary technology and expertise. However, the robotic exploration of Mars could, and should, continue in parallel with a manned lunar program.

"By pursuing parallel programs to build up a human spaceflight capability on the Moon and to advance robotic Mars exploration, there is a realistic chance that we will have developed both the human spaceflight expertise and the detailed knowledge of the martian environment to make human missions to the Red Planet both scientifically worthwhile and technically feasible before the middle of this century," said Dr. Crawford.

Contact:Dr. Ian Crawford School of Earth Sciences Birkbeck College Malet Street, London, WC1E 7HX Phone: +44 (0)207-679-3431 Mobile: +44 (0)777-62-34317 E-mail: i.crawford@ucl.ac.uk

Read the original news release at http://www.ras.org.uk/html/press/pn0409ras.html.

An additional article on this subject is available at http://www.spacedaily.com/news/mars-base-04f.html.

METHANE DETECTION POINTS TO LIFE ON MARSBy Robert ZubrinMars Society release

31 March 2004

Over the past week a series of discoveries have been announced that radically enhance the prospects for the search for life on Mars. The first announcements came for the MER science team led by Cornell University geologist Steven Squyres which identified the Meridani Planum landing site of the Opportunity rover as the shoreline of an ancient salty sea. "If you want to look for fossils, this is the place to go," NASA Associate Administrator for Space Science Ed Weiler commented.

As exciting as the MER results were, however, they were superceded two days later by the results of the team of V. A. Krasnopolsky, J. P. Mailard, and T. C. Owen, who published a paper announcing that, using the Canada-

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France-Hawaii telescope, they had detected methane in the martian atmosphere at a level of about 11 ppb. As small as this concentration is, it is anomalous, and cannot be explained by abiotic processes. We quote directly from the Krasnopolsky team's abstract, entitled "Detection of Methane in the Martian Atmosphere: Evidence for Life."

"...We detected the absorption by martian methane at a 3.9 sigma level. The observed CH4 mixing ratio is 11 ±4 ppb. Total photochemical loss of CH4 in the martian atmosphere is equal to 180,000/cm2-s, and the CH4 lifetime is 440 years. Heterogeneous loss of atmospheric methane is probably negligible, while the sink of CH4 during its diffusion through the regolith may be significant. There are no processes of CH4 formation in the atmosphere, so the photochemical loss must therefore be balanced by abiogenic and biogenic sources. The mantle outgassing of CH4 is 4000/cm2-s on the Earth, and smaller by an order of magnitude on Mars [i.e., much smaller than the required 180,000/cm2-s to make up the loss rate -RZ]. The calculated production of CH4 by cometary impacts is 2.3 percent of the methane loss. Methane cannot originate from an extinct biosphere, as in the case of "natural gas" on Earth, given the exceeding low limits on organic matter set by the Viking landers and the dry recent history which has been extremely hostile to the macroscopic life needed to generate the gas. Therefore, methanogenesis by living subterranean organisms is the most likely explanation for this discovery. Our estimates of the biomass and its production using the measured CH4 abundance show that the martian biota may be extremely scarce and that Mars may be generally sterile except for some oases."

One day after the publication of the Krasnopolsky group abstract, two more teams let it be known that they had measured similar results. One of the teams, led by Mike Mumma of NASA Goddard Spaceflight Center, used NASA's Infrared Telescope Facility in Hawaii and the international Gemini South observatory in Chile to make its measurements. The other team, led by Professor Vittorio Formisano, head of research of the Italian National Council for Research's Institute of Physics and Interplanetary Space, used the Planetary Fourier Spectrometer instrument on the ESA Mars Express spacecraft. Both the Formisano group and the Mumma group reported methane measurements in the 10 to 10.5 ppb range, in excellent agreement with each other and the 11 ppb results reported by the Krasnopolsky team.

So we now have three teams, using four different instruments, all reporting nearly identical methane measurements. The evidence for validity of the measurements must therefore be taken as very strong, and the key questions are those relating to interpretation, significance, and necessary follow-up.

Interpretation

For reasons explained in the Krasnopolsky abstract quoted above, the most likely interpretation is that the methane is a product of the metabolism of indigenous microbes. Methanogenic bacteria are common on Earth, and include members of the most archaic subgroup of bacterial life. The MER results show conclusively that surface environments that could have hosted rich microbial ecologies once existed on Mars, and geologically recent runoff channels imaged by Mars Global Surveyor (MGS) strongly indicate that subsurface reservoirs that could host microbes probably exist on Mars today. The alternative explanation, that the methane is a product of geothermal activity, appears unlikely in view of the TES and THEMIS measurements taken by NASA's MGS and Mars Odyssey orbiters. Either of these spacecraft should have been able to detect the thermal emissions associated with such activity, but they have not. This makes the geothermal explanation for the origin of the martian methane almost untenable. Furthermore, if somehow such hydrothermal environments did exist regardless, then they themselves would provide wonderful candidate environments for a host of microbial life forms. So, while not constituting definitive proof, the preponderance of the evidence strongly points to life.

Significance

The significance of the detection of life on Mars is enormous. There are two possibilities:1. The life detected on Mars has a common origin with Earth life.2. The life detected on Mars has a separate origin from Earth life.

Within the common origin possibility (1), there are three alternatives:a. Mars life is descended from Earth life.b. Earth life is descended from Mars life.c. Both Earth life and Mars life are descended from a third source.

While alternative (a) is possible in principle, it is the least likely of the three, since natural material transfer from Mars to Earth (via meteoritic impact) is easier than from Earth to Mars, and since Mars cooled quicker than the Earth (both planets were originally molten), life would have had an opportunity to originate on Mars first. Furthermore, one to the great mysteries about life on Earth is that we find no free-living organisms on Earth simpler than bacteria, which are actually highly complex—much too complex to represent the first life forms to emerge from chemistry. This anomaly has led numerous investigators since the 19th Century to suggest that life may not have originated on Earth at all, but represent an immigrant phenomenon. This leaves us with (b) or (c).

If (b) is true, and Mars is the homeland of life, then by going to Mars we have the possibility of discovering free-living life forms more primitive than bacteria, and who therefore present a living record of the missing links between chemistry and life. By examining them, we could read the book of life itself, and finally gain an understanding of the process that allowed for the creation of all living things.

If (c) is true, we would find no free-living organisms on Mars simpler than archaic bacteria of similar plan to those observed on Earth. In that case, we would have proof that the planets of our solar system were seeded early in their history by bacterial spores transported across interstellar space. This would be proof of the [hypothesis] of panspermia, and its inevitable consequence that life is present on billions of planets across our galaxy.

Alternatively, if (1) is false, then (2) must be true, in which case what we have on Mars is a second genesis. If this is the case, it would also imply that life is a general phenomenon in the universe, since we would have proof through success stories in two out of two cases that life tends to develop from non-life wherever it has an acceptable physical environment. Furthermore, however, the existence of such a second genesis would provide us with an opportunity to determine whether the biochemical plan of life that is common to all Earth life-forms is the pattern for all life everywhere, or whether we are just one peculiar example of a much vaster and more diverse tapestry of life that pervades the cosmos.

In other words, the detection of life on Mars is an invitation to an investigation whose results could provide us answers to the most profound questions humans have ever asked concerning the origin and fundamental nature of life.

Follow-up

The key issue therefore, is not whether there is life on Mars, but what is the life on Mars. To answer that question, drilling rigs will need to be set up on the martian surface capable of penetrating down to the locations of the subsurface liquid reservoirs which host the martian microbes, and water samples extracted. The water samples will then need to be cultured to see if they contain microbes, and if they do, then the microbes need to be imaged through a variety of techniques and subjected to a battery of biochemical tests. This sort of investigation can be carried out only by human explorers operating on the surface of Mars. NASA's new Space Exploration Initiative has just been handed its mission assignment.

An in-depth discussion of the significance of the methane detection discovery for the search for life on Mars will be held at the 7th International Mars Society Convention, Palmer House Hilton, Chicago, IL, August 19-22, 2004. Registration is now open at www.marssociety.org.

For further information about the Mars Society, visit our web site at www.marssociety.org.

MOLECULAR MIDWIVES HOLD CLUES TO THE ORIGIN OF LIFEFrom SpaceDaily

1 April 2004

Adding a small molecule, dubbed a "molecular midwife," researchers increased the rate of DNA formation in a chemical reaction 1,000 fold over a similar reaction lacking a midwife. The discovery is an important step in the effort to trace the evolution of life back to the earliest self-replicating molecules. The results are reported in the April 2 edition of the German chemistry journal Angewandte Chemie.

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"We are working to uncover how molecules similar to RNA and DNA first appeared on Earth around 4 billion years ago. Our theory is that small, simple molecules acted as templates for the production of the first RNA-like molecules. Many of these small molecules, or molecular midwives, would have worked together to produce RNA by spontaneously mixing and assembling with the chemical building blocks of RNA," said Nicholas Hud, associate professor of chemistry and biochemistry at the Georgia Institute of Technology.

Read the full article at http://www.spacedaily.com/news/life-04zl.html.

PLANETARY SYSTEMS WITH HABITABLE EARTHS?Royal Astronomical Society press notice PN04-13

1 April 2004

More than 100 planetary systems have already been discovered around distant stars. Unfortunately, the limitations of current technology mean that only giant planets (like Jupiter) have so far been detected, and smaller, rocky planets similar to Earth remain out of sight. How many of the known exoplanetary systems might contain habitable Earth-type planets? Perhaps half of them, according to a team from the Open University, led by Professor Barrie Jones, who will be describing their results today at the RAS National Astronomy Meeting in Milton Keynes.

Extrasolar planets have been found around stars in all regions of the sky as viewed from Earth. How many have earthlike planets? Image credit: S. G. Korzennik.

By using computer modeling of the known exoplanetary systems, the group has been able to calculate the likelihood of any 'Earths' existing in the so-called habitable zone—the range of distances from each central star where life as we know it could survive. Popularly known as the "Goldilocks" zone, this region would be neither too hot for liquid water, nor too cold.

By launching "Earths" (with masses between 0.1 and 10 times that of our Earth) into a variety of orbits in the habitable zone and following their progress with the computer model, the small planets have been found to suffer a variety of fates. In some systems the proximity of one or more Jupiter-like planets results in gravitational ejection of the "Earth" from anywhere in the habitable zone. However, in other cases there are safe havens in parts of the habitable zone, and in the remainder the entire zone is a safe haven.

Nine of the known exoplanetary systems have been investigated in detail using this technique, enabling the team to derive the basic rules that determine the habitability of the remaining ninety or so systems. The analysis shows that about half of the known exoplanetary systems could have an "Earth" which is currently orbiting in at least part of the habitable zone, and which has

been in this zone for at least one billion years. This period of time has been selected since it is thought to be the minimum required for life to arise and establish itself. Furthermore, the models show that life could develop at some time in about two thirds of the systems, since the habitable zone moves outwards as the central star ages and becomes more active.

Habitable moons

A different aspect of this problem is being studied by PhD student David Underwood, who is investigating the possibility that Earth-sized moons orbiting giant planets could support life. A poster setting out the possibilities will be presented during the RAS National Astronomy Meeting.

All of the planets discovered so far are of similar mass to Jupiter, the largest planet in our Solar System. Just as Jupiter has four planet-sized moons, so giant planets around other stars may also have extensive satellite systems, possibly with moons similar in size and mass to Earth. Life as we know it cannot evolve on a gaseous, giant planet. However, it could survive on Earth-sized satellites orbiting such a planet if the giant is located in the habitable zone.

In order to determine which of the gas giants located within habitable zones could possess a life-friendly moon, the computer models search for systems where the orbits of Earth-sized satellites would be stable and confined within the habitable zone for at least the one billion years needed for life to emerge.

The OU team's method of determining whether any putative "Earths" or Earth-sized satellites in habitable zones can offer suitable conditions for life to evolve can be applied rapidly to any planetary systems that are newly announced. Future searches for "Earths" and extraterrestrial life should also be assisted by identifying in advance the systems most likely to house habitable worlds.

The predictions made by the simulations will have a practical value in years to come when next-generation instruments will be able to search for the atmospheric signatures of life, such as large amounts of oxygen, on "Earths" and Earth-sized satellites.

Background

There are currently 105 known planetary systems other than our own, with 120 Jupiter-like planets orbiting them. Two of these systems contain three known planets, 11 contain two and the remaining 92 each have one. All but one of these planets has been discovered by their effect on their parent stars' motion in the sky, causing them to wobble regularly. The extent of these wobbles can be determined from information within the light received from the stars. The remaining planet was discovered as the result of a slight dimming of starlight caused by its regular passage across the disk of its parent star.

Future discoveries are likely to contain a higher proportion of systems that resemble our Solar System, where the giant planets orbit at a safe distance beyond the habitable zone. The proportion of systems that could have habitable "Earths" is, therefore, likely to rise. By the middle of the next decade, space telescopes should be capable of seeing any "Earths" and investigating them to see if they are habitable, and, indeed, whether they actually support life.

Contacts:Professor Barrie W. Jones Physics & Astronomy DepartmentOpen University Milton Keynes MK7 6AA Phone: +44 (0)1908-653229 E-mail: b.w.jones@open.ac.uk

David R. Underwood, Open University (see above) Phone: +44 (0)1908-652123, E-mail: b.w.jones@open.ac.uk

Further information and images can be found on the web at The Extrasolar Planets Encyclopedia (http://www.obspm.fr/encycl/encycl.html).

Read the original news release at http://www.ras.org.uk/html/press/pn0413ras.html.

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Additional articles on this subject are available at:http://www.astrobio.net/news/article903.htmlhttp://www.spacedaily.com/2004/040401171808.gnpjy4di.htmlhttp://www.spacedaily.com/news/extrasolar-04i.htmlhttp://spaceflightnow.com/news/n0403/31habitable/http://www.universetoday.com/am/publish/how_many_habitable_earths.html

SPACE DEFINES MARS SAMPLE RETURN MISSIONEADS Astrium press release

1 April 2004

Following award of the study contract by ESA, EADS Space has made significant progress in completing the first definition of a European Mars Sample Return (MSR) mission. While EADS Astrium is defining the overall mission and the spacecraft, EADS Space Transportation is responsible for the re-entry systems and a "Mars Ascent Vehicle"—a small rocket to carry the precious sample up through the martian atmosphere. The team at EADS Astrium, Stevenage is currently preparing for the Mid Term Review where two very different designs will have to be reduced to one.

In the first concept the launch vehicle lifts the sample from the surface of Mars and docks with the Earth Return Vehicle. In the second concept the launch vehicle releases the sample container into a low Mars orbit and the Earth Return Vehicle uses a capture mechanism to perform the rendezvous. The selection of the rendezvous concept has a significant impact on the overall mass, cost and complexity of the mission.

Marie-Claire Perkinson, Senior Systems Engineer at EADS Astrium, Stevenage, leading the study said. "Our industrial team, which includes EADS Space in France; Galileo Avionica in Italy, Sener in Spain and Utopia Consultancies in Germany has done a great job so far in proposing the two exciting concepts. We now have to select the best solution and then, once ESA has raised the appropriate support and funds for the implementation of the mission, launch could be as early as 2011."

Background

European astronauts may land on Mars one day, but getting them there and safely returning them to Earth will involve many steps and numerous technical challenges in propulsion, structures, computers and software. It will require sophisticated spacecraft to escape from Earth's orbit; fly to Mars, survive atmospheric entry and landing; operate on the surface; take-off; return to Earth and then finally get the crew back on terra firma. Long before this can be accomplished some key technologies must be demonstrated. The best way to do this is to fly a robotic mission with a scaled-down version of the eventual manned mission. This is exactly the goal of Mars Sample Return, the second flagship mission of the European Space Agency's Aurora planetary exploration initiative and one of the most eagerly awaited future space missions for the planetary scientists.

Because martian winds have transported dust across the planet's surface over millions of years, the MSR sample could include particles from many different sources, representing a wide variety of rock types and ages, like grains of sand on a beach. Each granule could offer completely different insights into the rich geologic past of the Red Planet. Scientists could now "look at the sample as if each grain were a rock," said Professor Colin Pillinger of the Open University. This would build on the decades of research already carried out on lunar rock samples.

EADS Space has used its unique heritage in building launch vehicles, planetary spacecraft and re-entry systems, combined with a deep understanding of the science goals to win the ESA mission study. ESA's Aurora Project Manager Bruno Gardini said "The Mars Sample Return mission is one of the most challenging missions ever considered by ESA. Not only does it include many new technologies and four or five different spacecraft, but it is also a mission of tremendous scientific importance and the first robotic mission with a similar profile to a possible human expedition to Mars."

Contact:Alistair Scott EADS Space (UK) Phone: +44 (0)1438-77-3698 Mobile: +44 (0)7887-826264

Additional articles on this subject are available at:http://www.spacedaily.com/news/mars-exomars-04d.htmlhttp://spaceflightnow.com/news/n0404/03marssample/http://www.universetoday.com/am/publish/mars_sample_return_two_directions.html

CHEAP COMMUNICATION SCHEMES FOR ETBy Seth ShostakFrom Space.com

1 April 2004

When it comes to signaling across space, power is paramount. Project Phoenix, which just wrapped up nine years of observations, was an acutely sensitive search for radio broadcasts. The experiment could have discerned an alien signal that was wafting a mere 0.00000000000000000001 watts onto the Arecibo telescope’s Cyclopean, twenty-acre aluminum mirror. I’ll state the obvious: that’s a small number. Indeed, if that incoming energy were collected for the length of time from the Big Bang until today (that is to say, for all time), the total would only be enough to blink a flashlight for a thousandth of a second.

Still, if you work out what sort of effort is required to produce that pipsqueak signal, the numbers get large. At 100 light-years distance, and assuming that the aliens are broadcasting in all directions equally, our cosmic buddies would need to pump their transmitter with 100 billion watts in order to drop that miniscule amount of power onto the Arecibo dish. That’s more than produced by all of America’s electric utility plants.

Of course, the extraterrestrials could be clever about their attempts to signal. For example, a rotating antenna might target only the flat part of the Milky Way Galaxy, sweeping it like a lighthouse beacon and doing so with considerably less juice than would be required by the all-sky, all-the-time approach. Another scheme would be for the aliens to use antenna arrays that sequentially "pinged" only interesting star systems. Again, this would save on the electric bills. Still, there’s no doubt that any of these transmitting schemes would be big-time undertakings, involving large structures, hefty electronics, and gobs of power.

Read the full article at http://www.space.com/searchforlife/seti_targeted_040401.html.

ASHES OF THE PHOENIXBy Peter BackusFrom Astrobiology Magazine

4 April 2004

Project Phoenix has left the building. There are empty spaces at Arecibo Observatory, but not for long. A new computer cluster is destined for the space occupied by fifteen Programmable Detection Modules. The cabinets that stored the spare components for the Phoenix search system are already reassigned to the RFI Monitoring and Electronics groups.

For the staff at Arecibo, another SETI project has ended, and life at the observatory goes on. But for us, life is in transition as we wrap up one project and begin another. As we wait in California for our equipment to arrive from Puerto Rico, it is a good time to look back on Project Phoenix. It wasn't "just another" SETI project.

Phoenix rose from the ashes of the NASA SETI Program that was terminated by the US Congress in 1993. The SETI Institute secured use of some of the search equipment developed for NASA under a long-term loan agreement and raised private funds to conduct a search. In the following year, Institute scientists and engineers doubled the size of the search system. In February 1995, just one month after the original NASA schedule, Project Phoenix began its targeted search of nearby stars.

The origin of Phoenix, while unusual, is not the reason it was unlike any other SETI project. Phoenix observed hundreds of stars over billions of frequency channels, with high sensitivity, and real-time signal detection and verification. No other search can compare on any aspect. A few searches have looked at some nearby stars in specific frequency bands. Phoenix observed more than

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700 stars, using some of the world's largest telescopes, over all available frequencies between 1200 and 3000 MHz with channels only 0.7 Hz wide.

In a universe brimming with stars, the search is on to find out whether life exists elsewhere. Image credit:NASA/STScI/ESA.

A few searches have used large telescopes, but they typically scan the sky and are limited to a single frequency band. Most of the time, these searches do not observe stars in our galaxy, but are actually looking at stars millions of light years away. In the fraction of time they observe stars in the Milky Way, they only spend 10 to 20 seconds per star. Phoenix only observed nearby stars in our galaxy and so could devote from 100 to 550 seconds per star per frequency band.

Almost all previous searches have one thing in common, unresolved signals. When you search for communication signals from interstellar distances, you will certainly detect signals from the Earth and its satellites. Phoenix perfected the real-time processing and verification techniques pioneered by Paul Horowitz of Harvard University. In a two-stage pipeline, Phoenix collected data and detected signals. Any signals not in a database of recent terrestrial interference were subjected to a type of observation unique to Phoenix. Using a second telescope, the star would be re-observed at the frequency of the candidate ET signal. The rotation of the Earth produces a distinct and different Doppler shift at the two telescopes. This technique, called pseudo-interferometry, would rule out signals not coming from the direction of the star. With this process and other tests, Project Phoenix has no unresolved signals.

So after nine-plus years of bringing a complex system of electronics to Australia, West Virginia, Georgia, England and Puerto Rico, Project Phoenix is over. We observed more than a million star-MHz, processed millions of signals, but found no evidence of another technological civilization in our galactic neighborhood. Only one task remains, to write the papers for the scientific journals. In the process of writing those reports, we also gather the "lessons learned," an important part of preparing for the next search.

Years from now, Phoenix will be seen as humanity's first systematic survey of the nearby stars. It was a major advance over all other SETI programs, but its superlatives will not last. New, more powerful searches will be made in the coming decades that will make the sensitivity, number of stars and frequency coverage of Phoenix seem small in comparison. But, it will always be our first big step in exploring our part of the Milky Way.

Read the original article at http://www.astrobio.net/news/article908.html.

An additional article on this subject is available at http://www.spacedaily.com/news/seti-04b.html.

EUROPA: LIVING WORLD OR FROZEN WASTELAND? AN INTERVIEW WITH CHRISTOPHER CHYBABy Henry BortmanFrom Astrobiology Magazine

5 April 2004

Christopher Chyba is the principal investigator for the SETI Institute lead team of the NASA Astrobiology Institute (NAI). Chyba formerly headed the SETI Institute's Center for the Study of Life in the Universe. His NAI team is pursuing a wide range of research activities, looking at both life's beginnings on Earth and the possibility of life on other worlds. Several of his team's research projects will examine the potential for life—and how one might go about detecting it—on Jupiter's moon Europa. Astrobiology Magazine's managing editor Henry Bortman recently spoke with Chyba about this work.

Astrobiology Magazine: One of the areas of focus of your personal research has been the possibility of life on Jupiter's moon Europa. Several of the projects funded by your NAI grant deal with this ice-covered world.

Christopher Chyba: Right. We're interested in interactions of life and planetary evolution. There are three worlds that are most interesting from that point of view: Earth, Mars and Europa. And we have a handful of projects going that are relevant to Europa. Cynthia Phillips is the leader of one of those projects; my grad student here at Stanford, Kevin Hand, heads up another one; and Max Bernstein, who's a SETI Institute P.I., is a leader on the third.

There are two components to Cynthia's projects. One that I think is really exciting is what she calls "change comparison." That goes back to her days of being a graduate associate on the Galileo imaging team, where she did comparisons to look for surface changes on another of Jupiter's moons, Io, and was able to extend her comparisons to include older Voyager images of Io.

We have Galileo images of Io, taken in the late 1990s, and we have Voyager images of Io, taken in 1979. So there are two decades between the two. If you can do a faithful comparison of the images, then you can learn about what's changed in the interim, get some sense of how geologically active the world is. Cynthia did this comparison for Io, then did it for the much more subtle features of Europa.

That may sound like a trivial task. And for really gross features I suppose it is. You just look at the images and see if something's changed. But since the Voyager camera was so different, since its images were taken at different lighting angles than Galileo images, since the spectral filters were different, there are all sorts of things that, once you get beyond the biggest scale of examination, make that much more difficult than it sounds. Cynthia takes the old Voyager images and, if you will, transforms them as closely as one can into Galileo-type images. Then she overlays the images, so to speak, and does a computer check for geological changes.

When she did this with Europa as part of her Ph.D. thesis, she found that there were no observable changes in 20 years on those parts of Europa that we have images for from both spacecraft. At least not at the resolution of the Voyager spacecraft—you're stuck with the lowest resolution, say about two kilometers per pixel. Over the duration of the Galileo mission, you've got at best five and a half years. Cynthia's idea is that you're more likely to detect change in smaller features, in a Galileo-to-Galileo comparison, at the much higher resolution that Galileo gives you, than you were working with images that were taken 20 years apart but that require you to work at two kilometers per pixel. So she's going to do the Galileo-to-Galileo comparison.

The reason this is interesting from an astrobiological perspective is that any sign of geological activity on Europa might give us some clues about how the ocean and the surface interact. The other component of Cynthia's project is to better understand the suite of processes involved in those interactions and what their astrobiological implications might be.

AM: You and Kevin Hand are working together to study some of the chemical interactions believed to be taking place on Europa. What specifically will you be looking at?

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CC: There are a number of components of the work I'm doing with Kevin. One component stems from a paper that Kevin and I had in Science in 2001, which has to do with the simultaneous production of electron donors and electron acceptors. Life as we know it, if it doesn't use sunlight, makes its living by combining electron donors and acceptors and harvesting the liberated energy.

For example, we humans, like other animals, combine our electron donor, which is reduced carbon, with oxygen, which is our electron acceptor. Microbes, depending on the microbe, may use one, or several, of many possible different pairings of electron donors and electron acceptors. Kevin and I were finding abiotic ways that these pairings could be produced on Europa, using what we understand about Europa now. Many of these are produced through the action of radiation. We're going to continue that work in much more detailed simulations.

We're also going to look at the survival potential of biomarkers at Europa's surface. That is to say, if you're trying to look for biomarkers from an orbiter, without getting down to the surface and digging, what sort of molecules would you look for and what are your prospects for actually seeing them, given that there's an intense radiation environment at the surface that should slowly degrade them? Maybe it won't even be that slow. That's part of what we want to understand. How long can you expect certain biomarkers that would be revelatory about biology to survive on the surface? Is it so short that looking from orbit doesn't make any sense at all, or is it long enough that it might be useful?

That has to be folded into an understanding of turnover, or so-called "impact gardening" on the surface, which is another component of my work with Cynthia Phillips', by the way. Kevin will be getting at that by looking at terrestrial analogs.

AM: How do you determine which biomarkers to study?

CC: There are certain chemical compounds that are commonly used as biomarkers in rocks that go back billions of years in the terrestrial past. Hopanes, for example, are viewed as biomarkers in the case of cyanobacteria. These biomarkers withstood whatever background radiation was present in those rocks from the decay of incorporated uranium, potassium, and so on, for over two billion years. That gives us a kind of empirical baseline for survivability of certain kinds of biomarkers. We want to understand how that compares to the radiation and oxidation environment on the surface of Europa, which is going to be much harsher.

Both Kevin and Max Bernstein are going to get after that question by doing laboratory simulations. Max is going to be irradiating nitrogen-containing biomarkers at very low temperatures in his laboratory apparatus, trying to understand the survivability of the biomarkers and how radiation changes them.

AM: Because even if the biomarkers don't survive in their original form they might get transformed into another form that a spacecraft could detect?

CC: That's potentially the case. Or they might get converted into something that is indistinguishable from meteoritic background. The point is to do the experiment and find out. And to get a good sense of the time scale.

That's going to be important for another reason as well. The kind of terrestrial comparison I just mentioned, while I think it's something we should know, potentially has limits because any organic molecule on the surface of Europa is in a highly oxidizing environment, where the oxygen's getting produced by the radiation reacting with the ice. Europa's surface is probably more oxidizing than the environment organic molecules would experience trapped in a rock on the Earth. Since Max will be doing these radiation experiments in ice, he will be able to give us a good simulation of the surface environment on Europa.

Read the original article at http://www.astrobio.net/news/article909.html.

An additional article on this subject is available at http://www.spacedaily.com/news/jupiter-europa-04c.html.

NEW ADDITIONS TO THE ASTROBIOLOGY INDEXBy David J. Thomashttp://www.lyon.edu/projects/marsbugs/astrobiology/

6 April 2004

Astrobiology and planetary engineering articleshttp://www.lyon.edu/projects/marsbugs/astrobiology/online_articles1.html

H. Bortman, 2004. Europa: living world or frozen wasteland? An interview with Christopher Chyba. Astrobiology Magazine.

Royal Astronomical Society, 2004. Life beneath the ice in the outer solar system? SpaceDaily.

Terrestrial extreme environments articleshttp://www.lyon.edu/projects/marsbugs/astrobiology/online_articles2.html

C. Bakermans and K. H. Nealson, 2004. Relationship of critical temperature to macromolecular synthesis and growth yield in Psychrobacter cryopegella. Journal of Bacteriology, 186(8):2340-2345.

V. P. Edgcomb, S. J. Molyneaux, M. A. Saito, K. Lloyd, S. Böer, C. O. Wirsen, M. S. Atkins and A. Teske, 2004. Sulfide ameliorates metal toxicity for deep-sea hydrothermal vent archaea. Applied and Environmental Microbiology, 70(4):2551-2555.

P. B. Price and T. Sowers, 2004. Temperature dependence of metabolic rates for microbial growth, maintenance, and survival. Proceedings of the National Academy of Sciences (USA), 101(13):4631-4636.

Human space exploration articleshttp://www.lyon.edu/projects/marsbugs/astrobiology/online_articles3.html

L. David, 2004. Moon-to-Mars feasible, experts say, but politics, lack of industry cooperation could jeopardize vision. Space.com.

Royal Astronomical Society, 2004. Europe targets human exploration of the Moon and Mars. SpaceDaily.

SETI articleshttp://www.lyon.edu/projects/marsbugs/astrobiology/online_articles4.html

P. Backus, 2004. Ashes of the Phoenix. Astrobiology Magazine.

H. Bortman, 2004. Can intelligent life thrive in close quarters? An interview with Christopher Chyba. Astrobiology Magazine.

S. Shostak, 2004. Cheap communication schemes for ET. Space.com.

Evolution (biological, chemical and cosmological) articleshttp://www.lyon.edu/projects/marsbugs/astrobiology/online_articles5.html

Georgia Institute of Technology, 2004. Molecular midwives hold clues to the origin of life. SpaceDaily.

Extrasolar planets articleshttp://www.lyon.edu/projects/marsbugs/astrobiology/online_articles7.html

Royal Astronomical Society, 2004. How many habitable Earths are out there? Universe Today.

Royal Astronomical Society, 2004. Hunt for extrasolar Earth-like planets intensifies. SpaceDaily.

CASSINI SIGNIFICANT EVENTSNASA/JPL release

25-31 March 2004

The most recent spacecraft telemetry was acquired from the Goldstone tracking station on Monday, March 29. 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=D0H_Amd62mxO-3BCLCXxIg.

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Science observations this week included Saturn approach movies to study the planet's atmosphere and its temporal variations, searches for new satellites, observations of Titan and searches for diffuse ring material, and solar wind observations. The Magnetometer Subsystem performed a Science Calibration Subsystem flight calibration, and commands were sent to the spacecraft to power on the Cassini Plasma Spectrometer and perform Real Time Interrupt testing.

Files for C44 were uplinked to the spacecraft this week. They included the background sequence, instrument expanded blocks, and an absolute timed Immediate/Delayed Action Program to perform an ACS Reaction Wheel Assembly bias. C44 begins execution on Thursday, April 1. During C44 the first time event "rocking downlink" will be performed for the Cosmic Dust Analyzer (CDA). During the downlink, the spacecraft rolls about the Z-axis in a back and forth manner. CDA will be performing rocking downlinks on 13 April.

Spacecraft Operations completed the Integrated Test Lab (ITL) dry run for the ACS flight software update version A8.6.7 on Thursday, 4/1/04. The test was important because this is the first time in flight an ACS computer will be reset and loaded with a flight software update during an on-going background sequence. The test was successful in that it did catch a missing vector needed for the C44 background. The missing vector has been added and the test will be re-run next week. Spacecraft Operations delivered version 10.3 of both IVP and KPT. This is the planned tour version of these ground software tools.

The Sequence Team released the preliminary version of the S01 background sequence and Phoebe Live Movable Block. Team members are in the process of reviewing the integrated sequence.

In the last week, 265 Imaging Science Subsystem (ISS) images and 36 Visual and Infrared Mapping Spectrometer (VIMS) cubes were returned and distributed, bringing the total of images acquired since the start of Approach Science up to 1969, and the number of cubes up to 663.

The Science Operations Plan Update process for S02, which includes the science occurring during and after the Saturn Orbit Insertion burn, had its official port 1 delivery this week. The team and engineering input products were merged and the merged product was handed off to ACS to perform the end-to-end pointing analysis. The S02 product will be handed off to the SSUP process on April 9.

Tour Science Plan presentation #5 to the flight team this week was part 2 of two parts on the Titan Orbiter Science Team plans for tour. This team was responsible for integration of science activities for the 44 targeted Titan flybys during the prime mission.

Delivery coordination meetings were held this week for Version 5.2 of AP_DOWNLINK consisting of bug fixes and new telemetry predicts, version 10.3 of Kinematic Prediction Tool and Inertial Vector Propagator, and Radio Science Subsystem tools LMBTRK Version 1.2 which incorporated the hard-limb approximation for faster calculations in the cases of large bending angles, for which high accuracy is not needed, POSTLM Version 1.1 which incorporated optimization and the capability to handle both ingress and egress,

and BISTAT Version 1.1 which incorporated atmospheric effects on the ray path.

As Cassini closes in on Saturn, its view is growing sharper with time and now reveals new atmospheric features in the planet's southern hemisphere. Atmospheric features, such as two small, faint dark spots, visible in the planet's southern hemisphere, will become clearer in the coming months. The spots are located at 38 degrees south latitude. The spacecraft's narrow angle camera took several exposures on March 8, 2004, which have been combined to create this natural color image. The image contrast and colors have been slightly enhanced to aid visibility. Moons visible in the lower half of this image are: Mimas (398 kilometers, or 247 miles across) at left, just below the rings; Dione (1,118 kilometers, or 695 miles across) at left, below Mimas; and Enceladus (499 kilometers, 310 miles across) at right. The moons had their brightness enhanced to aid visibility. The spacecraft was then 56.4 million kilometers (35 million miles) from Saturn, or slightly more than one-third of the distance from Earth to the Sun. The image scale is approximately 338 kilometers (210 miles) per pixel. The planet is 23 percent larger in this image than it appeared in the preceding color image, taken four weeks earlier. [http://photojournal.jpl.nasa.gov/catalog/PIA05385]

A Delivery Review was held for the Multi Mission Image Processing Laboratory point delivery D32.0.1. Testing results were reported and no issues were brought up. Operations were then halted for a validation and switchover period. This integrated system was then brought on-line as the operational system for Tour.

New content and graphics were released to the Saturn Observation Campaign website. Enhancements include compliance with the design features of the NASA portal, new information, and announcement of application process for new SOC members. The site can be accessed at http://jpl.convio.net/site/R?i=IKbTaYcOmL1O-3BCLCXxIg.

Cassini Outreach is performed not only by members of the Outreach staff located at JPL, but also by members of the flight team. A Radio and Plasma Wave Science instrument team member gave a series of talks in his local community to 22 first grade students at Weber Elementary School in Iowa City as well as 15 members of a Girl Scout Troop in Iowa City. In addition, a member of the Spacecraft Operations Office gave a talk to 21 3rd grade students at Paradise Canyon Elementary School in La Canada.

Wind-blown clouds and haze high in Saturn's atmosphere are captured in a movie made from images taken by the Cassini narrow angle camera between February 15 and February 19, 2004. This is the first movie ever made showing Saturn in these near-infrared wavelengths. The images were made using a filter sensitive to a narrow range of wavelengths centered at 889 nanometers, where methane in Saturn's atmosphere absorbs sunlight. For more information go to http://jpl.convio.net/site/R?i=CaW4WmTjYgVO-3BCLCXxIg..IA05384.jpg&type=image or http://jpl.convio.net/site/R?i=3qsBGaLal0ZO-3BCLCXxIg.

In the week that sees the 375th anniversary of the birth of the Dutch astronomer Christiaan Huygens, an international conference entitled "Titan: From Discovery to Encounter" is taking place, from 13 to 17 April, at ESA's

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Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 15, 6 April 2004

European Space Research and Technology Centre (ESTEC), Noordwijk, the Netherlands. The conference will bring together an international team of space scientists and historians to discuss topics such as: Christiaan Huygens and his connection with other 17th century

scientists, such as Cassini, Descartes and Newton; observation of Saturn and its moons from the 17th century to today; the scientific objectives of the Cassini/Huygens mission and its latest

observations on the way to the Saturnian system.

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.

Additional articles on this subject are available at:http://www.astrobio.net/news/article905.htmlhttp://www.space.com/scienceastronomy/cassini_closer_040402.htmlhttp://www.spacedaily.com/news/cassini-04c.htmlhttp://spaceflightnow.com/news/n0404/02saturnspots/

MARS EXPLORATION ROVERS STATUS REPORTSNASA/JPL releases

Spirit Finds Multi-Layer Hints of Past Water at Mars' Gusev SiteNASA/JPL release 2004-093, 1 April 2004

Clues from a wind-scalloped volcanic rock on Mars investigated by NASA's Spirit rover suggest repeated possible exposures to water inside Gusev Crater, scientists said Thursday. Gusev is halfway around the planet from the Meridiani region where Spirit's twin, Opportunity, recently found evidence that water used to flow across the surface.

This approximate true-color image taken by the panoramic camera on the Mars Exploration Rover Spirit shows the rock dubbed "Mazatzal" before the rover drilled into it with its rock abrasion tool. On sol 82, Spirit ground into a circular patch of the rock called "New York," then repeated this operation on sol 85 to complete the hole. Several observations were made during this grinding process with the rover's suite of scientific instruments. Preliminary results suggest that fluid may have been present during Mazatzal's formation. Images from the panoramic camera's blue, green and red filters (480, 530 and 600-nanometer filters) were combined to make this picture. Image credit: NASA/JPL/Cornell.

"This is not water that sloshed around on the surface like what appears to have happened at Meridiani. We're talking about small amounts of water, perhaps underground," said Dr. Hap McSween, a rover science team member from the University of Tennessee, Knoxville.

"The evidence is in the form of multiple coatings on the rock, as well as fractures that are filled with alteration material and perhaps little patches of alteration material," McSween said during a press conference at NASA's Jet Propulsion Laboratory, Pasadena, CA.

The rock, called "Mazatzal" after mountains in Arizona, lies partially buried near the rim of the crater informally named "Bonneville" inside the much larger Gusev Crater. Its light-toned appearance grabbed scientists' attention. After Spirit's rock abrasion tool brushed two patches on the surface with wire bristles, a gray, darker layer could be seen under the tan topcoat. The rock abrasion tool ground into the surface with diamond cutting teeth on March 26. Then, after an examination of the newly exposed material, it ground deeper into the rock two days later. A lighter-gray interior lies under the darker layer, and a bright stripe cuts across both.

This image was taken by the Mars Exploration Rover Spirit's panoramic camera during the rover's grinding of the rock dubbed "Mazatzal" with its rock abrasion tool. The picture shows the rock after the rover drilled 3.8 millimeters (.15 inches) into the target dubbed "New York" on Sol 82. The dark grey coating seen after brushing remains on the right side of the hole, while the left side is the underlying basaltic rock. This approximate true-color image was created using the panoramic camera's red, green and blue filters. Image credit: NASA/JPL/Cornell.

Dr. Jeff Johnson, a science team member from the U.S. Geological Survey's Astrogeology Team, Flagstaff, AZ, said the stripe "seems to be a fracture that water has flowed through, potentially with minerals precipitating from that fluid and lining the walls of the crack."

He and other scientists stressed that the interpretations are preliminary. "The team is, as always, trying to find time to digest these observations while also preparing for the next day's operations," Johnson said.

Spirit's alpha particle X-ray spectrometer checked what chemical elements were close to the surface of untreated, brushed, once-drilled and twice-drilled patches. "Miracles, miracles, miracles. We have a lot of work to do," the instrument's lead scientist, Dr. Rudi Rieder of the Max Planck Institute, Mainz, Germany, exclaimed about the results. For example, the ratio of bromine to chlorine seen inside the rock is unusually high and possibly a clue to alteration by water.

The final experiment on Mazatzal was to scrub the surface with the rock abrasion tool in a pattern of five circles arranged in a ring, with a sixth circle in the center. Besides creating a rock-art daisy, this task by the engineers of New York-based Honeybee Robotics, as well as JPL, produced a brushed patch big enough to fill the field of view of Spirit's miniature thermal emission spectrometer, said Dr. Steve Ruff of Arizona State University, Tempe. The tan outer surface appears to have a strikingly different mineral composition

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than the dark gray coating exposed by the brushing, but more time is needed to complete the analysis, he said.

McSween proposed that the light outer coat, dark inner coat and bright veins could have resulted from three different periods of the rock being buried, altered by fluids and unburied.

While scientists await transmission of additional data Spirit has collected about Mazatzal, the rover will be making its way toward the "Columbia Hills" about 2.3 kilometers (1.3 miles) away. Spirit left the rock and drove 36.5 meters (120 feet) early Thursday.

This Mars Exploration Rover Opportunity panoramic camera image shows "Bounce Rock," a rock the airbag-packaged rover struck while rolling to a stop on January 24, 2004. This is the largest rock for as far as the eye can see, approximately 35 centimeters (14 inches) long and 10 centimeters (4 inches) high. There appears to be a dusty coating on the top of parts of the rock, which may have been broken when it was struck by the airbags. The rock was about 5 meters (16 feet) from the rover when this image was obtained. This is an enhanced color composite image from sol 36 of the rover's journey, generated using the camera's L2 (750 nanometer), L5 (530 nanometer), and L6 (480 nanometer) filters. Image credit: NASA/JPL/Cornell.

This high-resolution panoramic camera blue filter image of the rock dubbed "Bounce" was obtained up close, just before the rover placed its instruments on the rock for detailed study. The rock has a number of shiny surfaces and textures on it, some of which are unlike those seen in the Eagle Crater rock outcrop. Also, the rock was apparently moved or shaken when it was hit with the airbags, as can be seen by the gap and cracks in the soil around the rock. This image from sol 65 of the rover's journey was acquired using the panoramic camera's 430 nanometer filter. Image credit: NASA/JPL/Cornell.

Opportunity set a one-day driving record on Mars on March 27 by covering 48.9 meters (160 feet) toward a rock called "Bounce Rock" because airbag

bounce marks show that the spacecraft hit it on landing day two months ago. "We're looking to break that record again very soon with longer and longer drives," said JPL's Chris Lewicki, flight director.

Before moving on across the plains of Meridiani, though, Opportunity will complete an investigation it has begun of Bounce Rock. The rock is unlike any seen on Mars before, said Dr. Jim Bell, lead scientist for the rovers' panoramic cameras. "There are some shiny surfaces on this rock," he said, describing them as "almost mirrorlike."

The two rovers' 18 cameras have now taken more than 20,000 images.

NASA's Mars Success Honored at Disney World Day of DiscoveryNASA release 04-114, 6 April 2004

NASA Administrator Sean O'Keefe joins NASA scientists, mission managers and a Mars rover today to help Disney's Epcot, at the Walt Disney World Resort, celebrate the success of the Mars Exploration Rovers Spirit and Opportunity. The Administrator's now famous quote, "We're back... and we're on Mars" is being added to a permanent collection of space-related quotations on the façade of Disney's latest attraction, "Mission: SPACE." The popular attraction launches visitors on a simulated space adventure to the Red Planet. "Mission: SPACE" combines NASA-based technology and imagery with the creative minds of Walt Disney Imagineering to deliver a one-of-a-kind exploration experience.

"The attraction builds on a foundation of science fact and provides visitors a fantasy ride into the future of exploration," said Administrator O'Keefe. "It's a realistic experience that can introduce a new generation of explorers to the excitement of science, technology and discovery."

"Mission: SPACE" officially opened October 9, 2003. It is Disney's most technologically advanced attraction, relying on visual imaging, motion control and centrifuge technology to send would-be astronauts on a futuristic voyage.

"Mission: SPACE appeals to the explorer in all of us," said Al Weiss, president of Walt Disney World Resort, Lake Buena Vista, Fla. "NASA's triumphant Mars missions embody that spirit of exploration. We are pleased and honored to have Administrator O'Keefe's comments taking their place at Mission: SPACE alongside those of others who dared to dream," he said.

NASA provided Disney's Imagineering team with tours, briefings and discussions about human and robotic missions, as well as the challenges future missions, like a trip to Mars, might present. The attraction took five years and some 350,000 work-hours to build.

During a special ceremony, an actual Mars rover made a ceremonial pass through wet cement. Administrator O'Keefe's quote will be affixed near the rover's tracks in the attraction's planetary courtyard. The latest developments and discoveries on Mars also were shared during the event.

As for the real rovers traversing Mars some 300 million miles from Earth, Spirit and Opportunity have made extraordinary discoveries and found important clues to a watery past on the martian surface. The Spirit rover is driving toward the "Columbia Hills," and Opportunity has been making close examinations of a martian rock known as "Bounce" before moving toward Endurance Crater.

For information about the latest developments on Mars and Disney's "Mission: SPACE" attraction on the Internet, visit:http://www.nasa.gov/vision/universe/solarsystem/mer_main.htmlhttp://disney.go.com/vacations/missionspace/ms_mainflash.html

For information about NASA and agency missions on the Internet, visit http://www.nasa.gov.

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, Ithaca, NY, at http://athena.cornell.edu.

Daily MER updates are available at:http://marsrovers.jpl.nasa.gov/mission/status_opportunity.htmlhttp://marsrovers.jpl.nasa.gov/mission/status_spirit.html

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Contacts:Guy Webster Jet Propulsion Laboratory, Pasadena, CAPhone: 818-354-5011

Donald SavageNASA Headquarters, Washington, DCPhone: 202-358-1547

Additional articles on this subject are available at:http://www.astrobio.net/news/article906.htmlhttp://www.space.com/marsrover/http://www.spacedaily.com/news/mars-mers-04zzzo.htmlhttp://spaceflightnow.com/mars/mera/040401status.htmlhttp://www.universetoday.com/am/publish/spirit_hints_past_martian_water.html

MARS EXPRESS: COMMISSIONING ALMOST COMPLETEESA release

31 March 2004

Since the last status report, the overall operational performance of the spacecraft and payload continued to be satisfactory. Some temporary problems were encountered with the Solid State Mass Memory (SSMM), which are currently under investigation. Remaining payload-commissioning activities are being performed until mid-April. The MARSIS radar will be deployed on 20 April and subsequently the spacecraft will be fully commissioned. Spacecraft resources, in particular power usage, are still constrained as Mars Express has encountered the first eclipse season, although the duration of eclipses per orbit is now slowly decreasing every day.

The status and performance of the orbiter payload in Mars orbit is excellent, with new high-resolution stereo and colour images and high-resolution spectral measurements of the planet being acquired, and further radio science data collected. The orbit of the Mars Express spacecraft continues to be very stable. Imaging instruments and spectrometers have begun global coverage science data acquisition. In particular, HRSC and OMEGA have started to perform mosaic and map construction. Since the last status report the following science material has been released.

30 March 2004, PFS: Evidence of Methane

Observations by the PFS instrument indicate that methane is present in the martian atmosphere. The measurements so far suggest that the amount of methane present is about 10 parts per billion.

22 March 2004, HRSC: Ascraeus Mons

The image reveals formations, associated with volcanic activity, that have also been witnessed on Earth, and elsewhere in the Solar System. The lava tubes are caused by crusting which occurs over a lava channel, effectively turning it into a tunnel. If the tunnel empties of all its lava then it will collapse and leave depression on the planetary surface.

17 March 2004, OMEGA: Water Evidence Confirmed

Further analysis of OMEGA measurements at the martian south pole have confirmed the presence of water ice. The majority of the water ice is in a permafrost region surrounding the central polar cap. The composition of this region is thought to be 15% water ice and 85% carbon dioxide ice. The measurements were made between 18 January and 11 February 2004—when summer was coming to an end at the southern cap. This meant the polar cap was at its smallest extent. In the coming months scientists expect the polar

cap to grow in size (as atmospheric carbon dioxide freezes onto the pole) and cover some of the permafrost region.

1 March 2004, HRSC: Hecates Tholus

The summit caldera of Hecates Thous, the largest volacno in the Elysium volcano group. The caldera shows multiple collapses caused by the emptying of the underlying magma chamber. On the sides of the volcano there is evidence for lava flow features.

Read the original news release at http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=34898.

Additional articles on this subject are available at:http://www.spacedaily.com/news/marsexpress-04j.htmlhttp://www.spacedaily.com/news/mars-life-04a.htmlhttp://www.spacedaily.com/upi/20040331-17482700.html

MARS GLOBAL SURVEYOR IMAGESNASA/JPL/MSSS release

25-31 March 2004

The following new images taken by the Mars Orbiter Camera (MOC) on the Mars Global Surveyor spacecraft are now available.

Craters and Wind Streaks (Released 25 March 2004)http://jpl.convio.net/site/R?i=sNxOv_cbM4NO-3BCLCXxIg

Russell Dunes (Released 26 March 2004)http://jpl.convio.net/site/R?i=681QkPwcAptO-3BCLCXxIg

South Polar Layers (Released 27 March 2004)http://jpl.convio.net/site/R?i=XTT8D_n7_pJO-3BCLCXxIg

Layered South Polar Slope (Released 28 March 2004)http://jpl.convio.net/site/R?i=pS0ZFnJmCZ1O-3BCLCXxIg

Gullies With Bright Material (Released 29 March 2004)http://jpl.convio.net/site/R?i=AJhOZ3zAkb1O-3BCLCXxIg

Crater in Cydonia (Released 30 March 2004)http://jpl.convio.net/site/R?i=fMPh-X9krCFO-3BCLCXxIg

West Candor Layers (Released 31 March 2004)http://jpl.convio.net/site/R?i=liBallDLR4tO-3BCLCXxIg

All of the Mars Global Surveyor images are archived at http://jpl.convio.net/site/R?i=nAkxphoQSs5O-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.

End Marsbugs, Volume 11, Number 15.

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