Marsbugs Vol. 11, No. 34 - Lyon College: Liberal Arts...

Marsbugs: The Electronic Astrobiology NewsletterVolume 11, Number 34, 31 August 2004

Editor/Publisher: David J. Thomas, Ph.D., Science Division, Lyon College, Batesville, Arkansas 72503-2317, USA. [email protected]

Marsbugs is published on a weekly to monthly basis as warranted by the number of articles and announcements. Copyright of this compilation exists with the editor, except for specific articles, in which instance copyright exists with the author/authors. Opinions expressed in this newsletter are those of the authors, and are not necessarily endorsed by the editor or by Lyon College. E-mail subscriptions are free, and may be obtained by contacting the editor. Information concerning the scope of this newsletter, subscription formats and availability of back-issues is available at http://www.lyon.edu/projects/marsbugs. The editor does not condone "spamming" of subscribers. Readers would appreciate it if others would not send unsolicited e-mail using the Marsbugs mailing lists. Persons who have information that may be of interest to subscribers of Marsbugs should send that information to the editor.

Articles and News

MARS SOCIETY CONVENTION A SMASHING SUCCESSMars Society release

Page 2 METEORITES SUPPLIED EARTH LIFE WITH PHOSPHORUS, SCIENTISTS SAYBy Lori Stiles

Page 4 SCIENTISTS SEEK SCENT OF LIFE IN METHANE AT MARS By Leonard David

Page 4 BRITISH SCIENTIST ASKS NASA FOR HELPING HAND TO MARSFrom Agence France-Presse and SpaceDaily

Page 4 PERIODIC DIMMING OF BRIGHT STARLIGHT REVEALS DISTANT PLANET National Center for Atmospheric Research release

Page 5 FOURTEEN TIMES THE EARTH—ESO HARPS INSTRUMENT DISCOVERS SMALLEST EVER EXTRA-SOLAR PLANET European Southern Observatory release

Page 7 CITIZEN OF THE SOLAR SYSTEM (INTERVIEW WITH DAVID MORRISON)From Astrobiology Magazine

Page 8 IGNITION THRESHOLD FOR IMPACT-GENERATED FIRESSouthwestern Research Institute release

Page 9 THE PATHWAY LESS TRAVELEDBy Karen Miller and Tony Phillips

Page 10 LIFE ON MARS: A DEFINITE POSSIBILITY By Henry Bortman

Page 11 NASA SATELLITES DETECT "GLOW" OF PLANKTON IN BLACK WATERSNASA release 2004-280

Page 12 SCIENTISTS DISCOVER FIRST OF A NEW CLASS OF EXTRASOLAR PLANETSNASA release 2004-212

Announcements

Page 13 CALL FOR PAPERS: FALL AGU MEETING SPECIAL SESSION SH11, "THE SPACE PHYSICS OF LIFE"From the NASA Astrobiology Institute Newsletter

Page 14 ASTROBIOLOGY SESSION TO MAKE AN “IMPACT” AT AGUFrom the NASA Astrobiology Institute Newsletter

Page 14 FOURTH EUROPEAN WORKSHOP ON EXO/ASTROBIOLOGY "LIFE IN EXTREME ENVIRONMENTS" NOVEMBER 2004From the NASA Astrobiology Institute Newsletter

Mission Reports

Page 15 CASSINI-HUYGENS UPDATESNASA/ESA releases

Page 16 DEEP IMPACT UPDATEFrom Deep News

Page 17 MARS EXPLORATION ROVERS UPDATESNASA/JPL releases

Page 18 MARS EXPRESS UPDATESESA releases

Page 20 MARS GLOBAL SURVEYOR IMAGESNASA/JPL/MSSS release

Page 20 MARS ODYSSEY BEGINS OVERTIME AFTER SUCCESSFUL MISSIONNASA/JPL release 2004-209

Page 21 MARS ODYSSEY THEMIS IMAGES23-27 August 2004

Page 22 ROSETTA: LGA THRESHOLD TEST SUCCESSFUL (REPORT FOR 6 TO 20 AUGUST)ESA release

MARS SOCIETY CONVENTION A SMASHING SUCCESSMars Society release

23 August 2004

The 7th International Mars Society convention has been a smashing success. Held at the historic Palmer House Hilton, Chicago, IL from August 19-22, the convention gathered 400 leading space scientists, engineers, government officials, entrepreneurs, activists, authors, and artists from many countries, including the USA, Canada, Mexico, Venezuela, Britain, Ireland, Spain, France, Belgium, Holland, Germany, Poland, Japan, China, India, and Australia to discuss ways and means of advancing the exploration and

settlement. Over 120 papers were presented, and over $50,000 was raised to further the work of the Mars Society. The conference received prominent coverage in many important Chicago area media, including The Chicago Tribune, the Chicago Sun-Times, the Journal-Herald, NPR Radio, and Fox TV News.

Among the highlights of the convention was the opening plenary by Mars Society President Robert Zubrin, who explained how a coherent joint Moon-Mars system development could enable the exploration of both bodies at much lower cost and risk, and shorter schedule than the wasteful "first Moon, then Mars" approach being pushed on NASA by certain quarters. Zubrin's presentation was followed by Dr. Steven Squyres, the Principal Investigator of

Marsbugs: The Electronic Astrobiology Newsletter, Volume 11, Number 34, 31 August 2004

the Mars Exploration Rover mission, which has discovered conclusive evidence for existence of large standing bodies of water for long durations of Mars' early history, habitable environments in which life could have once evolved. Squyres made it clear that he believed that human exploration was a necessary follow-up to the robotic exploration of Mars. This prompted one reporter to observe, "There are all these characters who say that Mars can be explored just with robots. But the guy who is actually exploring Mars with robots says we need to send people. That says it all."

Squyres was followed by Admiral Craig Steidle, NASA Associate Administrator for Exploration Systems, who is leading the space agencies efforts to return humans to the Moon and proceed onward to Mars. Steidle explained his plan for "spiral development" of the necessary systems for human exploration, and emphasized that he hoped to work closely with the Mars Society in moving the program forward. Steidle reemphasized this latter point in a comment which appeared in the Sunday Chicago Tribune August 22, in which he said; "Societies like the Mars Society are extremely important to us. They have an innovative and thorough process. We hope to continue the journey together."

Other exciting plenary talks included Dr. Mike Lembeck, who serves as Steidle division chief for requirements development, who explained how his group is laying out the roadmap for technology development to open the solar system; Dr. Bill Clancey, the head of human centered computing at NASA Ames Research Center, who presented a talk and video showing research his group has done at the Mars Society's Mars Desert Research Station investigating techniques for combined human-robot exploration on Mars; Dr. Stan Borowski, of the NASA Glenn Research Center, and the space agency's top expert on nuclear thermal rocket (NTR) propulsion, who explained how NTR technology could enable accelerated cost-effective exploration of the Moon, Mars, and beyond; Dr. Chris McKay, of NASA Ames Research Center, who explained the central significance of the search for life on Mars to resolving the question of the diversity and prevalence of life in the universe; Eric Anderson; President and CEO of Space Adventures Ltd., who explained how space tourism could potentially open a market that would establish the economic basis for commercially financed space settlement; Dr. Fred Pohl, a Grandmaster of science fiction (author of many award winning works, including The Space Merchants) who presented a science fiction visionary's view of "When will humankind become a spacefaring species." Dr. Scott Horowitz, astronaut and Shuttle commander, who piloted the second Hubble repair mission, presented an astronaut's view of human Mars exploration.

A major sensation was caused at the convention by the announcement by award-winning filmmaker Sam Burbank that he would be making a theatrical motion picture based on Robert Zubrin's novel "First Landing." Listing the various Hollywood horror pictures or shoot-em-ups nominally featuring Mars, Burbank drew a sharp distinction between those efforts and the kind of movie "First Landing" will be. "There never has been a movie actually about the human exploration of Mars. This will be the first." Burbank said, "It will not be set in the glorious science fiction future, but in our own time, and it will show the mission done with all the grungy realism of the kind of space travel we can really do. It's not going to show the Mars mission as being easy. It's not going to show it as being impossible. It's going to show it as being really tough, but doable, by a group of people who have what it takes to do it."

If the heavy applause Burbank received wasn't sufficient indication of the audience's appreciation of his project, what happened next certainly was, as following his remarks, paperback copies of "First Landing" were bought up literally by the dozens by conference members mobbing the book table.

Another highlight of the conference was the showing of advance clips of James Cameron's upcoming 3-D IMAX film "Aliens of the Deep." The footage for this movie was taken by Cameron and his team operating in a flotilla of submarines operating in conjunction with mobile telerobots to explore extremophile lie forms living around hydrothermal vents 3000 ft below the Atlantic. Cameron was going to show the movie to the conference himself, but a last minute emergency called him away. However in his place he sent his co-producer and fellow underwater explorer Steve Quayle, who presented the film to the conference. The film was quite literally incredible, with the explorers discovering at every turn weird creatures that exceed the imagination of Hollywood special effects artists. The movie will appear in IMAX theaters starting in January 2005, and we give it eight hundred thumbs up. No one should miss this film. There never, ever, has been anything like it.

There is so much that could be said, and not all can. But one thing that cannot escape mention is the joy and excitement brought to the convention by the space song contest. This contest, formally known as the Second Rouget De Lisle space song competition (so named after the musical genius who wrote "La Marseillaise," and thus gave the French Revolution its rousing anthem) was conducted over the past year, during which over 100 songs celebrating human space exploration were submitted. These were downselected to 20 finalists who sang off in public competition on the evening of Friday August 20. The audience of Mars Society members voted for the top six, who then sang in final competition at the Saturday night banquet. These songs were outstanding, and it was hard to judge between them. But for the record, the winners are:Gold Medal Category: 1st place, "Thank God Dreams Survive," by Bill, Tina, and Casey Swindell; 2nd place, "On to Mars," by Robert McNally.Silver Medal Category: 3rd Place, "Lullaby for Mars," by S. Miria Jo; 4th Place, "When Mice Become Men," by Janetta Deavers.Bronze Medal Category: 5th Place, "Make this World Come Alive," written by Leslie Fish, sung by Beatriz Serrato; 6th Place, "First Footprint," by Robert McNally.

All 20 of the finalists have been forwarded to Prometheus Music (producers of the highly successful "To Touch the Stars" CD which featured selections from the previous Rouget de Lisle" song contest) for possible inclusion in its next release. Songs from the first Rouget de Lisle contest have been posted and are available for downloading at the "Mars Songs" link at www.marssociety.org. By popular demand, there will be a Third Roget de Lisle competition for songs celebrating the human exploration of space next year.

Next year's Mars Society convention will be held next August at the University of Colorado in Boulder. The conference plenary hall there is known as the Glen Miller ballroom, after the famous musician and CU graduate, who was lost over the English Channel while traveling to lift the spirits of the troops trying to break out of the Normandy beachhead during June 1944. It's fitting that his ballroom should host the meeting of those seeking to break humanity out of its planetary beachhead. And this time the musicians to rouse their spirits will be there too.

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

METEORITES SUPPLIED EARTH LIFE WITH PHOSPHORUS, SCIENTISTS SAYBy Lori StilesUniversity of Arizona release

24 August 2004

University of Arizona scientists have discovered that meteorites, particularly iron meteorites, may have been critical to the evolution of life on Earth. Their research shows that meteorites easily could have provided more phosphorus than naturally occurs on Earth — enough phosphorus to give rise to biomolecules which eventually assembled into living, replicating organisms.

Phosphorus is central to life. It forms the backbone of DNA and RNA because it connects these molecules' genetic bases into long chains. It is vital to metabolism because it is linked with life's fundamental fuel, adenosine triphosphate (ATP), the energy that powers growth and movement. And phosphorus is part of living architecture it is in the phospholipids that make up cell walls and in the bones of vertebrates.

"In terms of mass, phosphorus is the fifth most important biologic element, after carbon, hydrogen, oxygen, and nitrogen," said Matthew A. Pasek, a doctoral candidate in UA's planetary sciences department and Lunar and Planetary Laboratory. But where terrestrial life got its phosphorus has been a mystery, he added.

Phosphorus is much rarer in nature than are hydrogen, oxygen, carbon, and nitrogen. Pasek cites recent studies that show there's approximately one phosphorus atom for every 2.8 million hydrogen atoms in the cosmos, every 49 million hydrogen atoms in the oceans, and every 203 hydrogen atoms in bacteria. Similarly, there's a single phosphorus atom for every 1,400 oxygen atoms in the cosmos, every 25 million oxygen atoms in the oceans, and 72 oxygen atoms in bacteria. The numbers for carbon atoms and nitrogen atoms, respectively, per single phosphorus atom are 680 and 230 in the cosmos, 974 and 633 in the oceans, and 116 and 15 in bacteria.

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Artist's illustration of early Earth, 4.5 billion years ago, about a year after a Mars-sized object hit Earth and formed the Earth-Moon system. The still molten moon with an impact in progress (upper left) is viewed from Earth's volcanic surface. Meteorites and comets—like the comet visible in the sky—delivered materials needed for life on Earth. Rings remaining from the collision and other debris, including moonlets not yet swept up by the moon, are visible. An Orion-like nebula appears at upper right. (Painting copyrighted by artist James V. Scotti, UA Lunar & Planetary Lab).

"Because phosphorus is much rarer in the environment than in life, understanding the behavior of phosphorus on the early Earth gives clues to life's origin," Pasek said.

The most common terrestrial form of the element is a mineral called apatite. When mixed with water, apatite releases only very small amounts of phosphate. Scientists have tried heating apatite to high temperatures, combining it with various strange, super-energetic compounds, even experimenting with phosphorous compounds unknown on Earth. This research hasn't explained where life's phosphorus comes from, Pasek noted.

Pasek with lab equipment. The tube contains a meteorite sample dissolved in fresh water.

Pasek began working with Dante Lauretta, UA assistant professor of planetary sciences, on the idea that meteorites are the source of living Earth's phosphorus. The work was inspired by Lauretta's earlier experiments that showed that phosphorus became concentrated at metal surfaces that corroded in the early solar system.

"This natural mechanism of phosphorus concentration in the presence of a known [in]organic catalyst (such as iron-based metal) made me think that aqueous corrosion of meteoritic minerals could lead to the formation of important phosphorus-bearing biomolecules," Lauretta said.

"Meteorites have several different minerals that contain phosphorus," Pasek said. "The most important one, which we've worked with most recently, is iron-nickel phosphide, known as schreibersite."

Image of schreibersite grain present in a thin-section of the enstatite meteorite, KLE 98300. This image was taken using reflected light and is 1 mm across. Image credit: Virginia Smith, UA Lunar & Planetary Laboratory.

Schreibersite is a metallic compound that is extremely rare on Earth. But it is ubiquitous in meteorites, especially iron meteorites, which are peppered with schreibersite grains or slivered with pinkish-colored schreibersite veins.

Last April, Pasek, UA undergraduate Virginia Smith, and Lauretta mixed schriebersite with room-temperature, fresh, de-ionized water. They then analyzed the liquid mixture using NMR, nuclear magnetic resonance.

"We saw a whole slew of different phosphorus compounds being formed," Pasek said. "One of the most interesting ones we found was P2O7 (two phosphorus atoms with seven oxygen atoms), one of the more biochemically useful forms of phosphate, similar to what's found in ATP."

Previous experiments have formed P207, but at high temperature or under other extreme conditions, not by simply dissolving a mineral in room-temperature water, Pasek said.

"This allows us to somewhat constrain where the origins of life may have occurred," he said. "If you are going to have phosphate-based life, it likely would have had to occur near a freshwater region where a meteorite had recently fallen. We can go so far, maybe, as to say it was an iron meteorite. Iron meteorites have from about 10 to 100 times as much schreibersite as do other meteorites.

"I think meteorites were critical for the evolution of life because of some of the minerals, especially the P207 compound, which is used in ATP, in photosynthesis, in forming new phosphate bonds with organics (carbon-containing compounds), and in a variety of other biochemical processes," Pasek said.

"I think one of the most exciting aspects of this discovery is the fact that iron meteorites form by the process of planetesimal differentiation," Lauretta said. That is, the building-blocks of planets, called planestesmals, form both a metallic core and a silicate mantle. Iron meteorites represent the metallic core, and other types of meteorites, called achondrites, represent the mantle.

"No one ever realized that such a critical stage in planetary evolution could be coupled to the origin of life," he added. "This result constrains where, in our solar system and others, life could originate. It requires an asteroid belt where planetesimals can grow to a critical size around 500 kilometers in diameter and a mechanism to disrupt these bodies and deliver them to the inner solar system."

Jupiter drives the delivery of planetesimals to our inner solar system, Lauretta said, thereby limiting the chances that outer solar system planets and moons will be supplied with the reactive forms of phosphorus used by biomolecules essential to terrestrial life. Solar systems that lack a Jupiter-sized object that can perturb mineral-rich asteroids inward toward terrestrial planets also have dim prospects for developing life, Lauretta added.

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This research was presented August 24th at the session "Astrobiology and the Origins of Life" of the 228th American Chemical Society national meeting in Philadelphia. The work is funded by the NASA program, Astrobiology: Exobiology and Evolutionary Biology.

[http://uanews.org/silk/downloads/schreibersite.jpg]Image of schreibersite grain present in a thin-section of the enstatite meteorite, KLE 98300. This image was taken using reflected light and is 1 mm across. Image credit: Virginia Smith, UA Lunar & Planetary Laboratory.

Contacts:Lori StilesUA News ServicesPhone: 520-621-1877

Matthew A. Pasek Phone: 520-621-1594 E-mail: [email protected]

Dante Lauretta Phone: 520-626-1138 E-mail: [email protected]

Read the original news release at http://uanews.org/cgi-bin/WebObjects/UANews.woa/8/wa/SciDetails?ArticleID=9567.

Additional articles on this subject are available at:http://www.astrobio.net/news/article1153.htmlhttp://www.spacedaily.com/news/early-earth-04l.htmlhttp://www.universetoday.com/am/publish/meteorites_provided_phosphorus.html

SCIENTISTS SEEK SCENT OF LIFE IN METHANE AT MARS By Leonard DavidFrom Space.com

24 August 2004

Sniffing out any whiff of biology on Mars has become a scientific battle of the bands—spectral bands that is. The purported detection of methane in the martian atmosphere by Mars Express, the European Space Agency (ESA) probe now orbiting the red planet, has sparked measurable debate.

ESA announced late last March that the Mars Express Planetary Fourier Spectrometer (PFS) had observed methane. That instrument is built to detect the presence of particular molecules by analyzing their "spectral fingerprints"—the specific way each molecule absorbs the sunlight it receives.

While the amount of methane seen by the PFS is very small—about 10 parts in a thousand million—the implications of the detection are large. Perhaps Mars isn’t a planet waiting to exhale, but one that is a thriving world of panting microbes. According to ESA experts, methane, unless it is continuously produced by a source, only survives in the martian atmosphere for a few hundreds of years because it quickly oxidizes to form water and carbon dioxide—both present in the martian atmosphere. So what’s refilling the atmosphere with methane?

Read the full article at http://www.space.com/scienceastronomy/mars_methane_040824.html.

BRITISH SCIENTIST ASKS NASA FOR HELPING HAND TO MARSFrom Agence France-Presse and SpaceDaily

24 August 2004

The British scientist who masterminded the ill-fated Beagle 2 probe, which vanished while attempting to land on Mars, said Tuesday he wanted to try again and has asked NASA for a ride to the Red Planet. Professor Colin Pillinger said he had written to the US space agency asking whether room might be found for a successor to Beagle on a much larger US mission to Mars due to depart in 2009. Speaking at a press conference to unveil an investigation into what went wrong with Beagle 2, which vanished shortly before it landed on Mars on Christmas Day last year, Pillinger said his team was "looking at the future".

NASA successfully landed a pair of probes on Mars around the same time as Beagle was lost, and is now planning to send a Mars Science Laboratory, a much larger device designed to roam the planet for years.

"I sent a letter to NASA saying, would you be interested in taking the Beagle 2 lander as a stand-alone package on a rover?" Pillinger said. "We're looking at any opportunity and every opportunity."

Read the full article at http://www.spacedaily.com/2004/040824133031.f4j7pkc6.html.

PERIODIC DIMMING OF BRIGHT STARLIGHT REVEALS DISTANT PLANET National Center for Atmospheric Research release

24 August 2004

Scientists have made their first direct discovery of a planet orbiting a bright star using a network of small telescopes and the "transit method" of detection. A periodic dimming of light from a bright star 500 light years away revealed the planet's presence. The star's intense light will allow scientists to explore the chemical makeup of the planet's atmosphere in future observations. A paper on the recent discovery will appear in The Astrophysical Journal Letters.

This is the first extrasolar planet discovery made by a dedicated survey of many thousands of relatively bright stars in large regions of the sky. It is also the first using the Trans-Atlantic Exoplanet Survey (TrES, pronounced "trace"), a network of small, relatively inexpensive telescopes designed to look specifically for planets orbiting bright stars. The telescopes make use of the transit technique, in which scientists analyze the shadow cast by a planet as it passes between its star and Earth.

This artist's rendition of TrES-1 shows it circled by small asteroids as it orbits its bright star. Illustration by David A. Aguilar, Harvard-Smithsonian Center for Astrophysics.

The discovery team includes scientists from the Astrophysical Institute of the Canaries (IAC), National Center for Atmospheric Research (NCAR), Harvard-Smithsonian Center for Astrophysics (CfA), Lowell Observatory, and California Institute of Technology. A team of scientists led by Timothy Brown (NCAR), David Charbonneau (CfA), and Edward Dunham (Lowell Observatory) developed the TrES network. Brown built the optical system of the telescope used in the discovery and located on Tenerife in the Canary Islands. A graduate student of Brown's, Roi Alonso Sobrino, of the IAC, discovered the planet, called TrES-1, after three years of persistent planet hunting.

"The fact that we can learn anything at all about a planet 500 light years away is astonishing," says Brown.

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The network's other two telescopes are located at the Lowell Observatory in Arizona and at Mt. Palomar, California. "It's almost paradoxical that, with the transit method, small telescopes are more efficient than the largest ones, in a time when astronomers are planning 100-meter telescopes," says Alonso.

Of the approximately 12,000 stars examined by the TrES survey, Alonso identified 16 possible candidates for planet transits.

"The TrES survey gave us our initial lineup of suspects. Then, we made follow-up observations to eliminate the imposters," says co-author Alessandro Sozzetti (CfA/University of Pittsburgh).

After compiling the list of candidates in late April, the researchers used telescopes at CfA's Whipple Observatory in Arizona and Oak Ridge Observatory in Massachusetts to obtain additional photometric (brightness) observations, as well as spectroscopic observations that eliminated eclipsing binary stars. In a matter of two month's time, the team had zeroed in on the most promising candidate. High-resolution spectroscopic observations by Guillermo Torres (CfA) and Sozzetti using the 10-meter-diameter Keck I telescope in Hawaii clinched the case.

"Without this follow-up work the photometric [brightness] surveys can't tell which of their candidates are actually planets. The proof of the pudding is a spectroscopic orbit [using the Doppler method] for the parent star. That's why the Keck observations of this star were so important in proving that we had found a true planetary system," says co-author David Latham (CfA).

More than 120 planets have been found by the Doppler method, which detects the gravitational pull of the planet on its star, but only gigantic planets can be "seen" this way. Moreover, the Doppler method gives indirect information about a planet. In 1999, the transit method was first used successfully to confirm the existence of a planet that had been discovered through its gravitational effect. Only now has the transit method resulted in a discovery involving a Jupiter-size planet circling a bright star. The success of the transit method opens the possibility of directly determining key information about the planet, such as its mass and radius (size), and its atmospheric components.

Next step: exploring the TrES-1 atmosphere

Scientists study an extrasolar planet's atmosphere by using a technique called spectroscopy. As starlight passes through the planetary atmosphere, light at some wavelengths disappears. This occurs as elements and compounds in the atmosphere, such as methane and carbon monoxide, absorb light at specific wavelengths. By observing which wavelengths are absorbed, Brown and colleagues will learn which elements are present in TrES-1's atmosphere. The scientists plan to search for water vapor first, since it can give clues about other chemical components.

"All that we have to work with is the light that comes from the star," says Brown. "It's much harder to learn anything when the stars are faint."

Three planets have been found with the transit method using large telescopes aimed at faint stars. However, the starlight is too dim to examine the planetary atmospheres.

Brown's research is funded by the National Science Foundation, NCAR's primary sponsor, and by NASA.

Read the original news release at http://www.ucar.edu/news/releases/2004/planet.shtml.

Additional articles on this subject are available at:http://www.astrobio.net/news/article1153.htmlhttp://cl.extm.us/?fe8a1d7273670c7b76-fe28167073670175701c72http://www.cnn.com/2004/TECH/space/08/24/planet.telescope.reut/index.htmlhttp://www.newscientist.com/news/news.jsp?id=ns99996327http://www.space.com/scienceastronomy/exoplanet_transit_040824.htmlhttp://www.spacedaily.com/news/extrasolar-04za.htmlhttp://www.spacedaily.com/news/extrasolar-04zb.htmlhttp://www.spacedaily.com/news/extrasolar-04zd.htmlhttp://www.universetoday.com/am/publish/small_telescope_finds_huge_planet.html

FOURTEEN TIMES THE EARTH—ESO HARPS INSTRUMENT DISCOVERS SMALLEST EVER EXTRA-SOLAR PLANET European Southern Observatory release

25 August 2004

A European team of astronomers [1] has discovered the lightest known planet orbiting a star other than the sun (an "exoplanet"). The new exoplanet orbits the bright star mu Arae located in the southern constellation of the Altar. It is the second planet discovered around this star and completes a full revolution in 9.5 days. With a mass of only 14 times the mass of the Earth, the new planet lies at the threshold of the largest possible rocky planets, making it a possible super Earth-like object. Uranus, the smallest of the giant planets of the Solar System has a similar mass. However Uranus and the new exoplanet differ so much by their distance from the host star that their formation and structure are likely to be very different.

Montage of the HARPS spectrograph and the 3.6m telescope at La Silla. The upper left shows the dome of the telescope, while the upper right illustrates the telescope itself. The HARPS spectrograph is shown in the lower image during laboratory tests. The vacuum tank is open so that some of the high-precision components inside can be seen.

This discovery was made possible by the unprecedented accuracy of the HARPS spectrograph on ESO's 3.6-m telescope at La Silla, which allows radial velocities to be measured with a precision better than 1 m/s. It is another clear demonstration of the European leadership in the field of exoplanet research.

Since the first detection in 1995 of a planet around the star 51 Peg by Michel Mayor and Didier Queloz from the Geneva Observatory (Switzerland), astronomers have learned that our Solar System is not unique, as more than 120 giant planets orbiting other stars were discovered mostly by radial-velocity surveys. This fundamental observational method is based on the detection of variations in the velocity of the central star, due to the changing direction of the gravitational pull from an (unseen) exoplanet as it orbits the star. The evaluation of the measured velocity variations allows to deduce the

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http://www.spacedaily.com/news/extrasolar-04zb.html

http://www.spacedaily.com/news/extrasolar-04za.html

http://www.space.com/scienceastronomy/exoplanet_transit_040824.html

http://www.newscientist.com/news/news.jsp?id=ns99996327

http://cl.extm.us/?fe8a1d7273670c7b76-fe28167073670175701c72


planet's orbit, in particular the period and the distance from the star, as well as a minimum mass [2].

The continued quest for exoplanets requires better and better instrumentation. In this context, ESO undoubtedly took the leadership with the new HARPS spectrograph (High Accuracy Radial Velocity Planet Searcher) of the 3.6-m telescope at the ESO La Silla Observatory. Offered in October 2003 to the research community in the ESO member countries, this unique instrument is optimized to detect planets in orbit around other stars ("exoplanets") by means of accurate (radial) velocity measurements with an unequalled precision of 1 meter per second.

HARPS was built by a European Consortium [3] in collaboration with ESO. Already from the beginning of its operation, it has demonstrated its very high efficiency. By comparison with CORALIE, another well known planet-hunting optimized spectrograph installed on the Swiss-Euler 1.2-m telescope at La Silla (cf ESO PR 18/98, 12/99, 13/00), the typical observation times have been reduced by a factor one hundred and the accuracy of the measurements has been increased by a factor ten. These improvements have opened new perspectives in the search for extra-solar planets and have set new standards in terms of instrumental precision.

The planetary system around mu Arae

The star mu Arae is about 50 light years away. This solar-like star is located in the southern constellation Ara (the Altar) and is bright enough (5 th

magnitude) to be observed with the unaided eye. Mu Arae was already known to harbor a Jupiter-sized planet with a 650 days orbital period. Previous observations also hinted at the presence of another companion (a planet or a star) much further away.

HARPS radial velocity measurements phase-folded with the orbital period of the newly found exoplanet (9.5 days). The measurements have been corrected from the effect of the two longer period companions. The semi-amplitude of the curve is less than 5 m/s! Coupled with the 9.5 days orbital period, this implies a minimum mass for the newly discovered planet of 14 times the mass of the Earth.

The new measurements obtained by the astronomers on this object, combined with data from other teams confirm this picture. But as François Bouchy, member of the team, states, "Not only did the new HARPS measurements confirm what we previously believed to know about this star but they also showed that an additional planet on short orbit was present. And this new planet appears to be the smallest yet discovered around a star other than the sun. This makes mu Arae a very exciting planetary system."

"Listening" to the star

During 8 nights in June 2004, mu Arae was repeatedly observed and its radial velocity measured by HARPS to obtain information on the interior of the star. This so-called astero-seismology technique (see ESO PR 15/01) studies the small acoustic waves which make the surface of the star periodically pulsate in and out. By knowing the internal structure of the star, the astronomers aimed at understanding the origin of the unusual amount of heavy elements observed in its stellar atmosphere. This unusual chemical composition could provide unique information to the planet formation history.

Says Nuno Santos, another member of the team: "To our surprise, the analysis of the new measurements revealed a radial velocity variation with a period of 9.5 days on top of the acoustic oscillation signal!"

This discovery has been made possible thanks to the large number of measurements obtained during the astero-seimology campaign. From this date, the star, that was also part of the HARPS consortium survey program, was regularly monitored with a careful observation strategy to reduce the "seismic noise" of the star.

These new data confirmed both the amplitude and the periodicity of the radial velocity variations found during the 8 nights in June. The astronomers were left with only one convincing explanation to this periodic signal: a second planet orbits mu Arae and accomplishes a full revolution in 9.5 days.

But this was not the only surprise: from the radial velocity amplitude, that is the size of the wobble induced by the gravitational pull of the planet on the star, the astronomers derived a mass for the planet of only 14 times the mass of the Earth! This is about the mass of Uranus, the smallest of the giant planets in the solar system. The newly found exoplanet therefore sets a new record in the smallest planet discovered around a solar type star.

At the boundary

The mass of this planet places it at the boundary between the very large earth-like (rocky) planets and giant planets. As current planetary formation models are still far from being able to account for all the amazing diversity observed amongst the extrasolar planets discovered, astronomers can only speculate on the true nature of the present object. In the current paradigm of giant planet formation, a core is formed first through the accretion of solid "planetesimals". Once this core reaches a critical mass, gas accumulates in a "runaway" fashion and the mass of the planet increases rapidly. In the present case, this later phase is unlikely to have happened for otherwise the planet would have become much more massive.

Furthermore, recent models having shown that migration shortens the formation time, it is unlikely that the present object has migrated over large distances and remained of such small mass. This object is therefore likely to be a planet with a rocky (not an icy) core surrounded by a small (of the order of a tenth of the total mass) gaseous envelope and would therefore qualify as a "super-Earth".

Further prospects

The HARPS consortium, led by Michel Mayor (Geneva Observatory, Switzerland), has been granted 100 observing nights per year during a 5-year period at the ESO 3.6-m telescope to perform one of the most ambitious systematic searches for exoplanets so far implemented worldwide. To this aim, the consortium repeatedly measures velocities of hundreds of stars that may harbor planetary systems.

The detection of this new light planet after less than 1 year of operation demonstrates the outstanding potential of HARPS for detecting rocky planets on short orbits. Further analysis shows that performances achieved with HARPS make possible the detection of big "telluric" planets with only a few times the mass of the Earth. Such a capability is a major improvement compared to past planet surveys. Detection of such rocky objects strengthens the interest of future transit detections from space with missions like COROT, Eddington and KEPLER that shall be able to measure their radius.

More information

The research described in this Press release has been submitted for publication to the leading astrophysical journal, Astronomy and Astrophysics. A preprint is available as a postscript file at http://www.oal.ul.pt/~nuno/.

Notes

[1] The team is composed of Nuno Santos (Centro de Astronomia e Astrofisica da Universidade de Lisboa, Portugal), François Bouchy and Jean-Pierre Sivan (Laboratoire d'astrophysique de Marseille, France), Michel Mayor, Francesco Pepe, Didier Queloz, Stéphane Udry, and Christophe Lovis (Observatoire de l'Université de Genève, Switzerland), Sylvie Vauclair, Michael Bazot (Toulouse, France), Gaspare Lo Curto and Dominique Naef (ESO), Xavier Delfosse (LAOG, Grenoble, France), Willy Benz and

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Christoph Mordasini (Physikalisches Institut der Universität Bern, Switzerland), and Jean-Louis Bertaux (Service d'Aéronomie de Verrière-le-Buisson, Paris, France).

[2] A fundamental limitation of the radial-velocity method is the unknown of the inclination of the planetary orbit that only allows the determination of a lower mass limit for the planet. However, statistical considerations indicate that in most cases, the true mass will not be much higher than this value. The mass units for the exoplanets used in this text are 1 Jupiter mass = 22 Uranus masses = 318 Earth masses; 1 Uranus mass = 14.5 Earth masses.

[3] HARPS has been designed and built by an international consortium of research institutes, led by the Observatoire de Genève (Switzerland) and including Observatoire de Haute-Provence (France), Physikalisches Institut der Universität Bern (Switzerland), the Service d'Aeronomie (CNRS, France), as well as ESO La Silla and ESO Garching.

Read the original news release at http://www.eso.org/outreach/press-rel/pr-2004/pr-22-04.html.

Additional articles on this subject are available at:http://www.astrobio.net/news/article1158.htmlhttp://www.cnn.com/2004/TECH/space/08/26/new.planet/index.htmlhttp://www.space.com/scienceastronomy/super_earth_040825.htmlhttp://www.universetoday.com/am/publish/smallest_extrasolar_planet_found.htmlhttp://story.news.yahoo.com/news?tmpl=story&u=/afp/space_astronomy_planets

CITIZEN OF THE SOLAR SYSTEM (INTERVIEW WITH DAVID MORRISON)From Astrobiology Magazine

25 August 2004

David Morrison is the senior scientist for the NASA Astrobiology Institute (NAI), an international research consortium of more than a dozen universities and space research centers. Astrobiology Magazine had the opportunity to talk with David Morrison about how astrobiology has changed since its conception as a scientific discipline a decade ago. Morrison was recently honored by the world's largest organization of planetary scientists—the Division for Planetary Sciences (DPS). The DPS awarded its 2004 Carl Sagan Medal to Morrison, a former student of Sagan's. The Sagan Medal is awarded annually to an active DPS member and researcher for their long-term excellence in communicating planetary science to the public. Morrison will receive the award at the organization's annual meeting to be held November 8-12, 2004, in Louisville, KY.

"We are honored by David's award," said G. Scott Hubbard, director of NASA Ames Research Center, Moffett Field, CA. "A doctoral student of Carl Sagan, David is that rare breed of scientist who combines research depth with the ability to popularize technical topics to non-scientists."

Morrison has been instrumental in illuminating the scientific basis for potential hazards due to asteroid and comet impacts, through refereed papers and popular articles and books. He created and implemented the impact hazard web site. Throughout his distinguished science career—as an expert on solar system small bodies and as an investigator for numerous spacecraft missions, including Voyager and Galileo—Morrison has dedicated himself to sharing the excitement of planetary exploration. In his testimony to the President's blue ribbon commission "Moon to Mars and Beyond", Morrison spoke to the limits of and opportunities for scientists as "we are in that transition from being citizens of planet Earth to being citizens of the solar system."

Astrobiology Magazine (AM): In early July, the Europeans proposed what they called the "Don Quixote" mission profile for asteroid mitigation. Their scenario entails detecting a dangerous asteroid on a terrestrial collision course, then intercepting the incoming rock with a scout probe followed by a destroyer probe. For the mission, the Europeans are soliciting international partners. Do you think this seek-and-destroy profile has a consensus among international partners as the best approach—or are there alternatives that merit consideration?

David Morrison (DM): The proposed Don Quixote mission, like the NASA Deep Impact comet mission, will certainly add to our knowledge about

asteroids and comets—knowledge that will be needed if we ever have to defend against an impact. Today we know far too little to try for a consensus as to how we would deflect an asteroid. One other approach under study is gradual deflection using a low-thrust ion engine, as proposed by the B612 Society for a follow-on Prometheus mission. Furthermore, different targets may well require different technologies to deal with them. A number of interesting ideas that have been suggested, but not much of the hard work to actually develop these approaches has been done.

Left: fragments of Comet P/Shoemaker-Levy 9 colliding with Jupiter (July 16-24, 1994). Image Credit: NASA. Right: HD 28185b is the first exoplanet discovered with a circular orbit within its star's habitable zone. Image credit: STScI Digitized Sky Survey.

AM: That same week in early July, the Oxford English Dictionary added "astrobiology" to their compendium. They define it as "search for life on other planets and in space." First how do you like to differentiate astrobiology from exobiology, as a discipline?

DM: I am glad to see "astrobiology" in the dictionary, but the definition you quote sounds more like "exobiology". Astrobiology is defined by its three theme questions, which include the origin and history of life on Earth and the future of life as well as the search for life beyond Earth—it sounds as if this is only one-third of the definition.

AM: Are there topics that astrobiology takes under its umbrella that traditionally have not been handled in exobiology literature?

DM: We might think of astrobiology as the natural evolution of exobiology. New scientific tools and concepts allow us to integrate the study of life in the universe—for example, to link the origin and evolution of life on Earth with the identification of possible habitable worlds beyond Earth.

Image of the Earth and Moon taken by the Galileo probe. Image credit: NASA. Sagan with mock-up of the Viking Mars lander, from the popular television series Cosmos.

AM: One field that seems to wax and wane in astrobiology circles is how best to be inclusive towards climatology. For instance, the question of how to generalize the early Earth and current climate research into a broader perspective on planetary preparations to host biology? Do you have a favorite example or illustration that highlights what a typical climate researcher may have to offer as expertise in an astrobiology survey?

DM: It seems to me that climate—especially in its long-term aspects—is intimately linked with habitability and the forces that drive evolutionary change. Studying the climate of Earth is also essential to assessing nature of other planetary atmospheres and the prospects for life there.

One of the big challenges in Earth's biological history is to understand how changes in the composition and greenhouse effect of our atmosphere may have compensated for the gradual increase in the luminosity of the Sun, thus stabilizing surface conditions. Presumably similar challenges to habitability have acted on planets around other solar-type stars. All these issues are linked, and solving one problem may lead to insights in other related areas.

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http://www.geocities.com/rickstvshows/cosmos.html

http://www.space.com/scienceastronomy/super_earth_040825.html

http://technology.jpl.nasa.gov/gallery/gl_pages/P21341bc.html


AM: Is there a breakout field that you personally think is being under-represented at astrobiology conferences or NAI partners that particularly seems intriguing to your vision for the discipline?

DM: I am pretty happy with what I see happening to astrobiology. Perhaps, however, we should be giving a greater visibility to what is likely to happen to life in the future, both on Earth and beyond the home planet, and to the ways discoveries in astrobiology may impact society. Astrobiology has made tremendous advances since its beginning less than 10 years ago, and it is especially gratifying to see the number of young scientists who want to make a career in astrobiology.

AM: The Spaceguard Survey of Earth-approaching asteroids is supposed to be 90 percent complete by the end of 2008. Will this goal be achieved, and what (if any) follow-on program will be adopted?

DM: We are making excellent progress with the Spaceguard Survey, with more than half of the NEAs (near-Earth asteroids) larger than 1 km already discovered, and more than 3/4 of those larger than 2 km). But the field of impact studies is still too young to determine what society seeks in the way of protection, and how much they are willing to pay.

For those who mainly fear an extinction event that might end human life forever, we have already achieved a considerable level of reassurance. For those whose concern is a global, civilization-threatening disaster, we are more than halfway complete. But for those who are primarily concerned about the smaller but more frequent impacts by sub-km NEAs, the astronomers have not achieved even 1 percent completeness in our surveys.

Last year a NASA Science Definition Team chaired by Grant Stokes of MIT recommended that future surveys be conducted, using larger telescopes, to extend down to 200 m diameter asteroids. The National Academy of Sciences has also recommended that this be done. But there is not a formal plan or commitment today to extend the surveys beyond 2008.

Read the original article at http://www.astrobio.net/news/article1156.html.

IGNITION THRESHOLD FOR IMPACT-GENERATED FIRESSouthwestern Research Institute release

26 August 2004

Scientists conclude that, 65 million years ago, a 10-kilometer-wide asteroid or comet slammed into what is now the Yucatán peninsula, excavating the Chicxulub impact crater and setting into motion a chain of catastrophic events thought to precipitate the extinction of the dinosaurs and 75 percent of animal and plant life that existed in the late Cretaceous period.

"The impact of an asteroid or comet several kilometers across heaps environmental insult after insult on the world," said Dr. Daniel Durda, a senior research scientist at Southwest Research Institute® (SwRI®). "One aspect of the devastation wrought by large impacts is the potential for global wildfires ignited by material ejected from the crater reentering the atmosphere in the hours after the impact."

One aspect of the devastation wrought by large asteroids colliding with the Earth is the potential for global wildfires to ignite in the hours after the impact. Scientists examined the threshold size impact required to create surface temperatures sufficient to spontaneously ignite forests to determine that the Chicxulub impact may have been the only known impact event to have caused global wildfires across several continents. The smaller Manicouagan and Popigai impact events most probably caused wildfires at the continental scale. Image credits: Josh O’Conner and wildlandfire.com.

Large impacts can blast thousands of cubic kilometers of vaporized impactor and target sediments into the atmosphere and above, expanding into space and enveloping the entire planet. These high-energy, vapor-rich materials reenter the atmosphere and heat up air temperatures to the point that vegetation on the ground below can spontaneously burst into flame.

"In 2002, we investigated the Chicxulub impact event to examine the extent and distribution of fires it caused," said Durda. This cosmic collision carved out a crater some 40 kilometers (25 miles) deep and 180 kilometers (112 miles) across at the boundary between two geologic periods, the Cretaceous, when the dinosaurs ruled the planet, and the Tertiary, when mammals took supremacy.

The large annular lake in this image shows the remnants of one of the largest impact craters still preserved on the surface of the Earth. Lake Manicouagan in northern Quebec, Canada, surrounds the central uplift of the impact structure, which is about 70 kilometers in diameter. Scientists believe the Manicouagan impact occurred 212 million years ago, toward the end of the Triassic period, when a five-kilometer-wide asteroid collided with the Earth. Image credit: NASA/GSFC/LaRC/JPL, MISR Team.

"We noted that fires appeared to be global, covering multiple continents, but did not cover the entire Earth," Durda continued. "That suggested to us that the Chicxulub impact was probably near the threshold size event necessary for igniting global fires, and prompted us to ask 'What scale of impact is necessary for igniting widespread fires?'"

In a new study, Durda and Dr. David Kring, an associate professor at the University of Arizona Lunar and Planetary Laboratory, published a theory for the ignition threshold for impact-generated fires in the August 20, 2004, issue of the Journal of Geophysical Research. Their research indicates that impacts resulting in craters at least 85 kilometers wide can produce continental-scale fires, while impact craters more than 135 kilometers wide are needed to cause global-scale fires.

To calculate the threshold size impact required for global ignition of various types of vegetation, Durda and Kring used two separate, but linked, numerical codes to calculate the global distribution of debris reentering the atmosphere and the kinetic energy deposited in the atmosphere by the material. The distribution of fires depends on projectile trajectories, the position of the impact relative to the geographic distribution of forested continents and the mass of crater and projectile debris ejected into the atmosphere. They also examined the threshold temperatures and durations required to spontaneously ignite green wood, to ignite wood in the presence of an ignition source (such as lightning, which would be prevalent in the dust-laden energetic skies following an impact event) and to ignite rotting wood, leaves and other common forest litter.

"The Chicxulub impact event may have been the only known impact event to have caused wildfires around the globe," Kring noted. "The Manicouagan (Canada) and Popigai (Russia) impact events, however, may have caused continental-scale fires. The Manicouagan impact occurred in the late Triassic, and the Popigai impact event occurred in the late Eocene, but neither has been firmly linked yet to the mass extinction events that occurred at those times."

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Kring is currently at the International Geological Congress in Florence, Italy, giving a keynote address on the Chicxulub impact event and its relationship to the mass extinctions at the Cretaceous-Tertiary boundary period. Durda is available for comment at the SwRI offices in Boulder, CO.

The Chicxulub impact site, shown in this gravity anomaly image, is 180 kilometers (112 miles) wide. A globally distributed layer of soot indicates that the Chicxulub impact was probably near the threshold size event necessary for igniting global fires across several continents. New research indicates that impacts resulting in craters at least 85 kilometers wide can produce continental-scale fires, while impact craters more than 135 kilometers wide are needed to cause global-scale fires. Image credit: NASA/University of Arizona Space Imagery Center.

High-resolution images for download are available at http://www.swri.org/press/impactfires.htm.

Contact:Deb SchmidCommunications DepartmentPO Drawer 28510San Antonio, TX 78228-0510Phone: 210-522-2254

Read the original news release at http://www.swri.org/9what/releases/2004/Ignition.htm.

An additional article on this subject is available at http://www.universetoday.com/am/publish/impact_set_world_fire.html.

THE PATHWAY LESS TRAVELEDBy Karen Miller and Tony PhillipsFrom NASA Science News

27 August 2004

Astronauts have long known that space travel is a good way to diet. The excitement of launch. Thrilling vistas seen from Earth orbit. Floating weightless. Maybe a touch of motion sickness. Who can eat at a time like that?

Rats, apparently, feel the same way. Rats in space (they've been there onboard the space shuttle) also under-eat. They grow lean compared to rats on Earth. Curiously, rats experiencing high gravity (inside gently-spinning centrifuges) under-eat, too. And this suggests there's more to the story than thrilling vistas: "Altered gravity somehow disrupts the natural ability of animals to maintain their own weight," says Barbara Horwitz, a professor of physiology at the University of California. No one understands exactly why that should be, but it's probably an important clue to the inner workings of

weight control—something that interests people on Earth just as much as astronauts in space. Horwitz is studying the phenomenon in rats at her laboratory in Davis, California.

Astronaut Loren Shriver eats M&Ms onboard the space shuttle Atlantis.

Although some of us who struggle with weight issues may find it hard to believe, animals, including humans, have evolved a complicated system for maintaining appropriate weight. You'd expect that: the bodies of animals that are too heavy, or not heavy enough, don't function properly. Feeding behavior is essential, not only to the health of individuals, but also to the survival of whole species. The body stores energy in fat, and there's a minimum amount an organism must have before it can get pregnant. "Animals that lose a lot of fat don't reproduce," says Horwitz. But the complex network that signals when to eat and when to stop eating can go awry. This could be a contributing cause of, e.g., the "obesity epidemic" in the United States, under-eating among astronauts, and maladies such as the "wasting syndrome" linked to AIDS.

Horwitz is particularly interested in leptin regulatory pathways. Leptin is a hormone that's key to regulating appetite: when it was first discovered in the mid-1990's it was regarded as a possible way to treat obesity in humans. Leptin is produced by fat cells. The more fat cells an organism has, the more leptin circulates through its body. Leptin manages appetite by activating receptors in the hypothalamus, a part of the brain. These receptors control the production of small signaling proteins called neuropeptides. Leptin increases the amount of neuropeptides that make you feel full, and decreases the amount of neuropeptides that make you feel hungry.

Horwitz is studying leptin regulatory pathways in rats: The animals live in a 2-g (twice normal gravity) centrifuge in individual, free-swinging cages, for as long as eight weeks. Even though they're working against twice the gravity they're used to, the rats don't seem to mind. They move around, they groom themselves. If they're allowed, they'll even breed on the centrifuge, says Horwitz.

Living in double gravity naturally requires more energy. The rats were offered all the food they wanted, yet, at first, they ate less than they needed to maintain their body mass—much like astronauts in low gravity. Horwitz and colleagues tested the rats (along with 1-g control groups) at 1, 2 and 8 weeks. During the first week, some of the rats' neuropeptides were mixed up. One, in particular, which stimulates feeding and therefore should have increased, actually went down. By the eighth week, things were back to normal—almost. The animals produced the same amount of neuropeptides in both 1-g and 2-g habitats. Double-gravity rats were finally eating as much as they needed. But they remained lean: they never regained the fat they lost at the beginning of the study.

"That means that the pathway somehow was changed," says Horwitz. "The relationship between the amount of fat, and how much leptin was secreted, and the functioning of the feedback system is altered in high gravity."

Horwitz hopes to pinpoint the exact mechanisms by further testing the rats' genes. Each neuropeptide in the appetite feedback loop is produced or "expressed" by a gene that has been activated. Using a technology called DNA microarrays, Horwitz and colleagues examine thousands of rat genes at a time. They can see which genes have been activated, and how active they

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are. Understanding the chemical pathways at this basic level could lead to "countermeasures," i.e., treatments to restore broken leptin regulatory systems.

Many researchers now believe that leptin's main role in humans is protecting against weight loss more so than weight gain. It makes sense: food surpluses are a relatively new phenomenon. Humans have evolved to withstand deprivation, not excess. This makes leptin, potentially, even more important to astronauts. It's part of a regulatory pathway that keeps them from becoming too lean when stress, motion sickness and bland food take away their appetites.

Horwitz's research is important here on Earth, too. People with weight control problems like obesity may have defective leptin regulatory pathways: they tend to have plenty of leptin coursing through their bodies, but it does not cause them to eat less. The big question is why. Maybe their leptin receptors don't work well, or their neuropeptides aren't produced properly. Or it could be something else entirely. Somewhere, along the pathway less traveled, lies the answer.

Read the original article at http://science.nasa.gov/headlines/y2004/27aug_fatrat.htm.

LIFE ON MARS: A DEFINITE POSSIBILITY By Henry Bortman From Astrobiology Magazine

30 August 2004

Was Mars once a living world? Does life continue, even today, in a holding pattern, waiting until the next global warming event comes along? Many people would like to believe so. Scientists are no exception. But so far no evidence has been found that convinces even a sizable minority of the scientific community that the red planet was ever home to life. What the evidence does indicate, though, is that Mars was once a habitable world. Life, as we know it, could have taken hold there.

The discoveries made by NASA's Opportunity rover at Eagle Crater earlier this year (and being extended now at Endurance Crater) leave no doubt that the area was once "drenched" in water. It might have been shallow water. It might not have stuck around for long. And billions of years might have passed since it dried up. But liquid water was there, at the martian surface, and that means that living organisms might have been there, too.

Left: rover computer rendering on the edge of a depression, much like Opportunity's perch on the edge of Endurance Crater. Image credit: Don Maas/NASA/JPL. Right: liquid water may have flowed episodically over the surface of Mars in the planet's distant past. Artist conception of a delta filling a crater. Image credit: NASA.

So suppose that Eagle Crater—or rather, whatever land formation existed in its location when water was still around—was once alive. What type of organism might have been happy living there? Probably something like bacteria. Even if life did gain a foothold on Mars, it's unlikely that it ever evolved beyond the martian equivalent of terrestrial single-celled bacteria. No dinosaurs; no redwoods; no mosquitoes—not even sponges, or tiny worms. But that's not much of a limitation, really. It took life on Earth billions of years to evolve beyond single-celled organisms. And bacteria are a hardy lot. They are amazingly diverse, various species occupying extreme niches of temperature from sub-freezing to above-boiling; floating about in sulfuric acid; getting along fine with or without oxygen. In fact, there are few habitats on Earth where one or another species of bacterium can't survive.

What kind of microbe, then, would have been well adapted to the conditions that existed when Eagle Crater was soggy? Benton Clark III, a Mars

Exploration Rover (MER) science team member, says his "general favorite" candidates are the sulfate-reducing bacteria of the genus Desulfovibrio. Microbiologists have identified more than 40 distinct species of this bacterium.

Eating rocks

We tend to think of photosynthesis as the engine of life on Earth. After all, we see green plants nearly everywhere we look and virtually the entire animal kingdom is dependent on photosynthetic organisms as a source of food. Not only plants, but many microbes as well, are capable of carrying out photosynthesis. They're photoautotrophs; they make their own food by capturing energy directly from sunlight. But Desulfovibrio is not a photoautotroph; it's a chemoautotroph. Chemoautotrophs also make their own food, but they don't use photosynthesis to do it. In fact, photosynthesis came relatively late in the game of life on Earth. Early life had to get its energy from chemical interactions between rocks and dirt, water, and gases in the atmosphere. If life ever emerged on Mars, it might never have evolved beyond this primitive stage.

Desulfovibrio makes its home in a variety of habitats. Many species live in soggy soils, such as marshes and swamps. One species was discovered all snug and cozy in the intestines of a termite. All of these habitats have two things in common: there's no oxygen present; and there's plenty of sulfate available.

Round spore of sulfur-reducing bacterium. The rod-shaped Desulfotomaculum exists both in an unsporulated, "free-tumbling" form in sulfate-rich water and this round sporulated form. Image Credit: Mazák Károly.

Sulfate reducers, like all chemoautotrophs, get their energy by inducing chemical reactions that transfer electrons between one molecule and another. In the case of Desulfovibrio, hydrogen donates electrons, which are accepted by sulfate compounds. Desulfovibrio, says Clark, uses "the energy that it gets by combining the hydrogen with the sulfate to make the organic compounds" it needs to grow and to reproduce.

The bedrock outcrop in Eagle Crater is chock full of sulfate salts. But finding a suitable electron donor for all that sulfate is a bit more troublesome. "My calculations indicate [that the amount of hydrogen available is] probably too low to utilize it under present conditions," says Clark. "But if you had a little bit wetter Mars, then there [would] be more water in the atmosphere, and the hydrogen gas comes from the water" being broken down by sunlight.

So water was present; sulfate and hydrogen could have as an energy source. But to survive, life as we know it needs one more ingredient carbon. Many living things obtain their carbon by breaking down the decayed remains of other dead organisms. But some, including several species of Desulfovibrio, are capable of creating organic material from scratch, as it were, drawing this critical ingredient of life directly from carbon dioxide (CO2) gas. There's plenty of that available on Mars.

All this gives reason to hope that life that found a way to exist on Mars back in the day when water was present. No one knows how long ago that was, or whether such a time will come again. It may be that Mars dried up billions of years ago and has remained dry ever since. If that is the case, life is unlikely to have found a way to survive until the present.

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Drill hole from rock abrasion tool showing spiral or fluted rock form below the surface of El Capitan. Image credit: NASA/JPL/Cornell.

Tilting toward life

But Mars goes through cycles of obliquity, or changes in its orbital tilt. Currently, Mars is wobbling back and forth between 15 and 35 degrees' obliquity, on a timescale of about 100,000 years. But every million years or so, it leans over as much as 60 degrees. Along with these changes in obliquity come changes in climate and atmosphere. Some scientists speculate that during the extremes of these obliquity cycles, Mars may develop an atmosphere as thick as Earth's, and could warm up considerably. Enough for dormant life to reawaken.

"Because the climate can change on long terms," says Clark, ice in some regions on Mars periodically could "become liquid enough that you would be able to actually come to life and do some things—grow, multiply, and so forth—and then go back to sleep again" when the thaw cycle ended. There are organisms on Earth that, when conditions become unfavorable, can form "spores which are so resistant that they can last for a very long time. Some people think millions of years, but that's a little controversial."

Desulfovibrio is not such an organism. It doesn't form spores. But its bacterial cousin, Desulfotomaculum, does. "Usually the spores form because there's something missing, like, for example, if hydrogen's not available, or if there's too much [oxygen], or if there's not sulfate. The bacteria senses that the food source is going away, and it says, 'I've got to hibernate,' and will form the spores. The spores will stay dormant for extremely long periods of time. But they still have enough machinery operative that they can actually sense that nutrients are available. And then they'll reconvert again in just a matter of hours, if necessary, to a living, breathing bacterium, so to speak. It's pretty amazing," says Clark.

That is not to say that future Mars landers should arrive with life-detection equipment tuned to zero in on species of Desulfovibrio or Desulfotomaculum. There is no reason to believe that life on Mars, if it ever emerged, evolved along the same lines as life on Earth, let alone that identical species appeared on the two planets. Still, the capabilities of various organisms on Earth indicate that life on Mars—including dormant organisms that could spring to life again in another few hundred thousand years—is certainly possible.

Clark says that he doesn't "know that there's any organism on Earth that could really operate on Mars, but over a long period of time, as the martian environment kept changing, what you would expect is that whatever life had started out there would keep adapting to the environment as it changed."

Detecting such organisms is another matter. Don't look for it to happen any time soon. Spirit and Opportunity were not designed to search for signs of life, but rather to search for signs of habitability. They could be rolling over fields littered with microscopic organisms in deep sleep and they'd never know it. Even future rovers will have a tough time identifying the martian equivalent of dormant bacterial spores.

"The spores themselves are so inert," Clark says, "it's a question, if you find a spore, and you're trying to detect life, how do you know it's a spore, [and not] just a little particle of sand? And the answer is: you don't. Unless you can find a way to make the spore do what's called germinating, going back to the normal bacterial form." That, however, is a challenge for another day.

Read the original article at http://www.astrobio.net/news/article1163.html.

NASA SATELLITES DETECT "GLOW" OF PLANKTON IN BLACK WATERSNASA release 2004-280

31 August 2004

For the first time, scientists may now detect a phytoplankton bloom in its early stages by looking at its red "glow" under sunlight, due to the unique data from two NASA satellites. According to a study conducted in the Gulf of Mexico, this phenomenon can forewarn fishermen and swimmers about developing cases of red tides that occur within plumes of dark-colored runoff from river and wetlands, sometimes causing "black water" events.

Florida red tide bloom of Karenia brevis, and Karenia brevis under a microscope (inset). Image credit: Woods Hole Oceanographic Institute/NOAA and NOAA/CHBR.

Dark-colored river runoff includes nitrogen and phosphorus, which are used as fertilizers in agriculture. These nutrients cause blooms of marine algae called phytoplankton. During extremely large phytoplankton blooms where the algae is so concentrated the water may appear black, some phytoplankton die, sink to the ocean bottom and are eaten by bacteria. The bacteria consume the algae and deplete oxygen from the water that leads to fish kills.

Chuanmin Hu and Frank Muller-Karger, oceanographers at the College of Marine Science of University of South Florida, St. Petersburg, FL, used fluorescence data from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) instruments aboard both NASA's Terra and Aqua satellites. MODIS detects the glow or phytoplankton fluorescence, from the plant's chlorophyll. The human eye cannot detect the [far-]red fluorescence.

The ability to detect glowing areas of water helps researchers identify whether phytoplankton are present in large dark water patches that form off the coast of Florida. Without these data, it is impossible to differentiate phytoplankton blooms from plumes of dark river runoff that contain few individual phytoplankton cells. Because colored dissolved organic matter that originates in rivers can absorb similar amounts of blue and green color signals as plants do, traditional satellites that simply measure ocean color cannot distinguish phytoplankton blooms within such patches.

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http://marsrovers.jpl.nasa.gov/gallery/all/1/m/030/1M130859833EFF0454P2959M2M1.JPG


The image on the left was captured by the MODIS instrument on October 19, 2003. Overlaid were the locations where water samples were collected to determine their Karenia brevis (toxic phytoplankton) abundance between September 19 and October 19, 2003. Large circles mean higher abundance. Smallest circles mean "not present." The dark plume flows from the central Florida coast to the Dry Tortugas. The image on the right is from the same time period. The fluorescence increases from dark blue to green, yellow and red. Image credit: NASA/USF.

Although satellites cannot directly measure nutrients in lakes, rivers, wetlands and oceans, remote sensing technology measure the quantities of plankton. Scientists can then calculate how much nutrient might be needed to grow those amounts of plankton. Hu and others used this technique to study the nature and origin of a dark plume event in the fall of 2003 near Charlotte Harbor, off the south Florida coast. Moderate concentrations of one of Florida's red tide species, were found from water samples.

"Our study traces the black water patches near the Florida Keys to some 200 kilometers (124 miles) away upstream," said Hu. "These results suggest that the delicate Florida Keys ecosystem is connected to what happens on land and in two remote rivers, the Peace and Caloosahatchee, as they drain into the ocean. Extreme climate conditions, such as abnormally high rainfall in spring and summer 2003, may accelerate such connections," he added.

The left image is a MODIS image which shows dark water on October 9, 2003. The arrows show the average wind speed and direction (day and night) from the QuikScat scatterometer. October 8-14 is in black, October 15-19 is in red. Areas of low salinity or salt usually occur near the mouths of rivers. In the image on the right, the white lines on this color enhanced image depict the approximate locations of Everglades rivers. Image credit: NASA/USF/NOAA/UM.

These findings are based on scientific analyses of several things. Data used include satellite ocean color from MODIS and Sea-viewing Wide Field-of-view Sensor (SeaWiFS), and wind data from NASA's QuikSCAT satellite. U.S. Geological Survey, National Oceanic and Atmospheric Administration (NOAA), Florida's Fish and Wildlife Research Institute, and other organizations provided rain, river discharge, and field survey information. By knowing which way the winds blow and the currents flow, Hu and colleagues can predict where black water may move.

Red tides occur every year off Florida and are known to cause fish kills, coral stress and mortality, and skin and respiratory problems in humans. Previous

studies show that prolonged "black water" patches cause water quality degradation and may cause coral death. The use of remote sensing satellites provides effective means for monitoring and predicting such events.

The link between coastal runoff and black water events is an example of how land and ocean ecosystems are linked together. "Coastal and land managers over large areas need to work together, to alleviate more black water events from taking place in the future," said Muller-Karger.

This study appeared in a recent issue of the American Geophysical Union's Geophysical Research Letters. Coauthors of the article include Gabriel Vargo and Merrie Beth Neely from University of South Florida and Elizabeth Johns from NOAA's Atlantic Oceanographic and Meteorological Laboratory. NASA's Science Directorate works to improve the lives of all humans through the exploration and study of Earth's system, the solar system and the Universe.

For more information and images on the Internet, visit http://www.gsfc.nasa.gov/topstory/2004/0826planktonglow.html.

Gretchen Cook-AndersonNASA Headquarters, Washington, DCPhone: 202-358-0836)

SCIENTISTS DISCOVER FIRST OF A NEW CLASS OF EXTRASOLAR PLANETSNASA release 2004-212

31 August 2004

This artist's concept shows the newly discovered Neptune-sized extrasolar planet circling the star Gliese 436. Gliese 436 is a type of low-mass star called an M dwarf, about four-tenths the size of our Sun. It appears reddish because it is cooler than a typical Sun-like star. The new planet is only the second to be found orbiting an M dwarf star, and is one of the smallest extrasolar planets detected to date. It circles Gliese 436 every 2.6 days at a small fraction of the distance between the Sun and Earth, or 4.1 million kilometers (2.6 million miles). In this depiction, the planet appears gaseous like Jupiter, with a cloudy atmosphere. In reality, astronomers do not know if this planet is gaseous, or rocky, like Earth and Mars. The temperature of the planet is estimated to be around 370 Celsius (698 Fahrenheit), though—if locked in place like our Moon—its dark side might experience temperatures of 200 Celsius (392 Fahrenheit) or colder.

Astronomers announced today the first discovery of a new class of planets beyond our solar system about 10 to 20 times the size of Earth—far smaller than any previously detected. The planets make up a new class of Neptune-sized extrasolar planets. In addition, one of the new planets joins three others around the nearby star 55 Cancri to form the first known four-planet system.

The discoveries consist of two new planets. They were discovered by the world renowned planet-hunting team of Drs. Paul Butler and Geoffrey Marcy of the Carnegie Institute of Washington and University of California, Berkeley, respectively; and Barbara McArthur of the University of Texas, Austin. Both findings were peer-reviewed and accepted for future publication in the Astrophysical Journal. NASA and the National Science Foundation funded the research.

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http://www.gsfc.nasa.gov/topstory/2004/0826planktonglow.html


"NASA, along with our partner NSF, is extremely proud of this significant planetary discovery," said Al Diaz, Associate Administrator of NASA's Science Mission Directorate. "The outcome of the tremendous work of the project scientists is a shining example of the value of space exploration."

"These Neptune-sized planets prove that Jupiter-sized, gas giants aren't the only planets out there," Marcy said. Butler added, "We are beginning to see smaller and smaller planets. Earth-like planets are the next destination."

Future NASA planet-hunting missions, including Kepler, the Space Interferometry Mission and the Terrestrial Planet Finder, will seek such Earth-like planets. Nearly 140 extrasolar planets have been discovered. Both of the new planets stick very close to their parent stars, whipping around them in a matter of days. The first planet, discovered by Marcy and Butler, circles a small star called Gliese 436 about every two-and-one-half days at just a small fraction of the distance between Earth and the Sun, or 4.1 million kilometers (2.6 million miles). This planet is only the second known to orbit an M dwarf, a type of low-mass star four-tenths the size of our own sun. Gliese 436 is located in our galactic backyard, 30 light-years away in the constellation Leo.

This artist's concept shows the newfound Neptune-sized planet—one of the smallest extrasolar planets detected to date—circling the star 55 Cancri. The planet joins three others in orbit around 55 Cancri to form the first known four-planet system. It is the innermost of the bunch, whipping around the star every 2.8 days at just a fraction of the distance between the Sun and Earth, or 5.6 million kilometers (3.5 million miles). In this illustration, the new planet is depicted as having a rocky composition, like Earth or Mars. In reality, astronomers do not know if the planet is rocky, or gaseous like Jupiter. Being so close to its parent star, the planet's temperature is at least a scorching 1500 Celsius (2700 Fahrenheit). The star 55 Cancri is about 5 billion years old, a bit lighter in weight than the Sun, and is located 41 light-years away in the constellation Cancer.

The second planet, found by McArthur, speeds around 55 Cancri in just under three days, also at a fraction of the distance between Earth and the sun, at approximately 5.6 million kilometers (3.5 million miles). Three larger planets also revolve around the star every 15, 44 and 4,520 days, respectively. Marcy and Butler discovered the outermost of these in 2002. It is still the only known Jupiter-like gas giant to reside as far away from its star as our own Jupiter. The 55 Cancri is about 5 billion years old, a bit lighter than the sun, and is located 41 light-years away in the constellation Cancer. "55 Cancri is a premier laboratory for the study of planetary system formation and evolution," McArthur said.

Because the new planets are smaller than Jupiter, it is possible they are made of rock, or rock and ice, rather than gas. According to the scientists, the planets may have, like Earth, formed through gradual accumulation of rocky bodies. "A planet of Neptune's size may not have enough mass to hold onto gas, but at this point we don't know," Butler said.

Both discoveries were made using the "radial velocity" technique, in which a planet's gravitational tug is detected by the wobble it produces in the parent star. Butler, Marcy and collaborators, including Dr. Deborah Fischer of San Francisco State University and Dr. Steven Vogt of the University of California, Santa Cruz, discovered their "Neptune" after careful observation of

950 nearby stars with the W. M. Keck Observatory in Mauna Kea, Hawaii. They were able to spot such a relatively small planet, because the star it tugs on is small and more susceptible to wobbling.

This illustration compares the size of the newfound Neptune-sized planets beyond our solar system to the sizes of Earth and Jupiter. The new planets are only about 20 times the mass of Earth, or about two times the actual size or diameter - much smaller than the majority of Jupiter-sized extrasolar planets detected so far. Astronomers do not know if these planets are rocky, like Earth, or gaseous, like Jupiter. Rocky planets are smaller in diameter than gaseous ones of the same mass.

McArthur and collaborators Drs. Michael Endl, William Cochran and Fritz Benedict of the University of Texas discovered their "Neptune" after obtaining over 100 observations of 55 Cancri from the Hobby- Eberly Telescope at McDonald Observatory in West Texas. Combining this data with past data from Marcy, Fischer and Butler from the Lick Observatory in California, and archival data from NASA's Hubble Space Telescope, the team was able to model the orbit of 55 Cancri's outer planet. This, in turn, allowed them to clearly see the orbits of the other three inner planets, including the new Neptune-sized one.

More images and animations are available at http://planetquest.jpl.nasa.gov/news/ssu_images.html.

Information about NASA's hunt for extrasolar planets is available at http://planetquest.jpl.nasa.gov.

Contacts:Whitney ClavinJet Propulsion Laboratory, Pasadena, CAPhone: 626-354-4673 or 354-5011

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

Read the original news release at http://www.nasa.gov/vision/universe/newworlds/extrasolar-083104.html.

CALL FOR PAPERS: FALL AGU MEETING SPECIAL SESSION SH11, "THE SPACE PHYSICS OF LIFE"From the NASA Astrobiology Institute Newsletter

20 August 2004

Earth, Mars, Europa, Titan, and other potentially habitable bodies in our solar system are continually exposed to the effects of their interplanetary and magnetospheric space environments. We invite contributions on direct or indirect astrobiological effects of natural and artificial space environment components (magnetic and electric fields, plasma, energetic particles and photons, radio and plasma waves, dust) on potentially habitable environments, and to related sites of pre-biotic organic synthesis in the solar system and the local interstellar medium. Presentations are also solicited on techniques exploiting space environment interactions (e.g., magnetospheric, auroral,

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atmospheric, surface) in searches for such environments within and beyond the Solar System.

Abstracts are due at the meeting web site, http://www.agu.org/meetings/fm04/, by September 1 for regular mail and by September 9 on-line. The journal Astrobiology has tentatively agreed to publish papers related to the theme of this session with manuscript submissions due by March 31, 2005. Please contact the conveners for further information (contact information is available at the web site).

ASTROBIOLOGY SESSION TO MAKE AN “IMPACT” AT AGUFrom the NASA Astrobiology Institute Newsletter

20 August 2004

The American Geophysical Union 2004 Fall Meeting takes place 13-17 December 2004 in San Francisco.

Session B18: Evaluating the role of impact in the end Permian and end Traissic mass extinctions. How do these compare to other impact or extinction events?

Conveners: Peter D. Ward (University of Washington), e-mail: [email protected]. Luann Becker (University of California Santa Barbara, Institute of Crustal Studies, Depepartment of Geological Sciences) e-mail: [email protected]. Frank T. Kyte (University of California Los Angeles, Center for Astrobiology, Institute of Geophysics and Planetary Physics), e-mail: [email protected].

This session will compare known evidence of impact in the stratigraphic record, such as the wealth of geochemical, mineralogical, and paleontological data from the Cretaceous/Tertiary and late Eocene events, to evaluate the possibility that impact was the sole, or an important component in the cause of the end Permian and end Triassic extinctions. We will specifically look at new information about possible meteoritic and impact tracers, as well as proposed craters, that have recently been invoked as evidence of impact related to the Permian extinction, and new data on the end Triassic extinction to assess the role of impact (if any) in these extinction events.

Additional information is available at the meeting web site, http://www.agu.org/meetings/fm04/.

FOURTH EUROPEAN WORKSHOP ON EXO/ASTROBIOLOGY "LIFE IN EXTREME ENVIRONMENTS" NOVEMBER 2004From the NASA Astrobiology Institute Newsletter

20 August 2004

The 4th European Workshop on Exo/Astrobiology, "Life in Extreme Environments," will be held Monday, 22nd to Thursday, 25th November 2004 at the Walton Hall Campus of the Open University in Milton Keynes. For more information regarding the Workshop and how to register, please visit the web page at http://physics.open.ac.uk/eana/.

CASSINI-HUYGENS UPDATESNASA/ESA releases

Cassini-Huygens Mission Status ReportNASA/JPL release 2004-208, 23 August 2004

The Cassini spacecraft successfully completed a 51-minute engine burn that will raise its next closest approach distance to Saturn by nearly 300,000 kilometers (186,000 miles). The maneuver was necessary to keep the spacecraft from passing through the rings and to put it on target for its first close encounter with Saturn's moon Titan on October 26.

Mission controllers received confirmation of a successful burn at 11:15 AM Pacific Time today. The spacecraft is approaching the highest point in its first and largest orbit about Saturn. Its distance from the center of Saturn is about 9 million kilometers (5.6 million miles), and its speed just prior to today's burn was 325 meters per second (727 miles per hour) relative to Saturn. That means it is nearly at a standstill compared to its speed of about 30,000 meters

per second (67,000 miles per hour) at the completion of its orbit insertion burn on June 30.

"Saturn orbit insertion got us into orbit and this maneuver sets us up for the tour," said Joel Signorelli, spacecraft system engineer for the Cassini-Huygens mission at NASA's Jet Propulsion Laboratory, Pasadena, CA.

The maneuver was the third longest engine burn for the Cassini spacecraft and the last planned pressurized burn in the four-year tour. The Saturn obit insertion burn was 97 minutes long, and the deep space maneuver in December 1998 was 88 minutes long.

"The October 26 Titan encounter will be much closer than our last one. We'll fly by Titan at an altitude of 1,200 kilometers (746 miles), 'dipping our toe' into its atmosphere," said Signorelli. Cassini's first Titan flyby on July 2 was from 340,000 kilometers (211,000 miles) away.

Over the next four years, the Cassini orbiter will execute 45 Titan flybys as close as approximately 950 kilometers (590 miles) from the moon. In January 2005, the European-built Huygens probe that is attached to Cassini will descend through Titan's atmosphere to the surface.

The Cassini-Huygens mission 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, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, DC. JPL designed, developed and assembled the Cassini orbiter.

Cassini-Huygens Periapsis Raising ManeuverESA release, 24 August 2004

The Cassini-Huygens spacecraft has successfully performed its scheduled Periapsis Raising Maneuver (PRM). A 51-minute burn of the primary engine corrected the spacecraft trajectory to place it on a course to encounter Saturn’s largest moon, Titan, in October. The maneuver also raised the periapsis (point of closest approach to Saturn) by over 400 000 km. Prior to the PRM the Cassini-Huygens spacecraft had been in a highly elliptical orbit around Saturn following the SOI maneuver of 1 July. The orbital elements with respect to Saturn's equatorial plane were:Semi-major axis: 4,585,959 kmEccentricity: 0.98239Periapsis radius: 80,731 kmApoapsis radius: 9,091,186 kmInclination: 11.534°

If left in this orbit the spacecraft would not encounter Titan with the correct velocity to make further orbital changes for the successful deployment of the Huygens probe, and would return to a periapsis point 20,000 km above Saturn's cloud tops and also a second ring plane crossing.

The PRM was performed when Cassini-Huygens was near the outer point in its orbit at about 9 million kilometers from Saturn. Here the orbital velocity had reduced to a mere 325 ms-1 compared to the 30,000 ms-1 after the SOI engine burn on 30 June. The PRM engine burn imparted an increase in the orbital velocity of between 350 and 390 ms-1. Later confirmation will give the exact new orbital parameters which were targeted to be:Semi-major axis: 4,790,340 kmEccentricity: 0.896Periapsis radius: 498,970 kmApoapsis radius: 9,081,700 kmInclination: 12.83°

The new periapsis is located in the safe, tenuous outer regions of Saturn’s E-ring instead of only 20,000 km above Saturn’s cloud tops. This periapsis is of little significance because the Titan encounter on 26 October, at an altitude of only 1200 km, will change the orbital parameters again.

Titan Encounters

During the first three orbits around Saturn (Orbit A, B and C) Cassini-Huygens will make three encounters with Titan. The Huygens probe will be released on 25 December 2004 to descend in Titan's atmosphere on 14 January 2005.

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First three orbits after SOI with 3 Titan flybys and the Huygens Probe Release. [http://sci.esa.int/science-e-media/img/7d/PRM-390.gif]

Read the original news release at http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=35709.

Cassini Significant Events for 19-25 August 2004NASA/JPL release, 27 August 2004

The most recent spacecraft telemetry was acquired from the Madrid tracking station on Wednesday, August 25. The Cassini spacecraft is in an excellent state of health and is operating normally. Information on the present position and speed of the Cassini spacecraft may be found on the "Present Position" web page located at http://saturn.jpl.nasa.gov/operations/present-position.cfm.

At the beginning of this week, an encounter strategy meeting was held for encounters Titan a, and Titan b. This included Orbit Trim Maneuvers (OTM) 2, 3, 4 (Ta-3), 5, 6, and 7. Immediately following, the OTM-2 maneuver and command approval meetings were held. On August 23, OTM-2, the periapsis raise maneuver, was successfully completed. The purpose of this maneuver was to raise Cassini's next closest approach distance to Saturn on October 28 by nearly 300,000 kilometers. The maneuver was necessary to keep the spacecraft from passing through the rings and to put Cassini on target for its first close encounter with Saturn's moon Titan on October 26. A "quick look" of telemetry immediately after the maneuver showed a burn duration of 51 minutes, 8 seconds, giving a delta-V of 392.9 m/s. The maneuver was the third longest engine burn for the Cassini spacecraft and the last planned pressurized burn in the four-year tour. The Saturn obit insertion burn in July was 97 minutes long, and the deep space maneuver in December 1998 was 88 minutes long.

Cassini caught a hint of Rhea's heavily cratered surface as it sped rapidly away from the moon on its first orbit of Saturn. There is a noticeable brightening near the left limb of the icy moon. Cassini will have its first flyby of Rhea in November 2005.

A new, special procedure for obtaining range points for navigation after burn completion was used during this maneuver. The DSN transmitter was left ON while the spacecraft was turned off Earth-point, and ranging disabled. After the spacecraft came back to Earth-point, a Magellan acquisition or MAQ was performed. This was done in order to obtain range points in the DSN pass after the maneuver. The technique worked successfully.

This Cassini spacecraft narrow angle camera view of Saturn's southern polar region features a bright white spot, or storm, surrounded by faint, darker swirls of clouds.

Latch valve 10 was left open for 33 minutes after the burn completed in order to further pressurize the oxidizer and fuel tanks for future maneuvers. The propulsion team indicated the burn was fully pressurized with the regulator performing normally. Tank pressures, latch valve performance, etc, were

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http://saturn.jpl.nasa.gov/operations/present-position.cfm


normal. For more details on this maneuver refer to the Cassini Web site, News Release 2004-208 at http://jpl.convio.net/site/R?i=PdgKRrSbsrJO-3BCLCXxIg..k=true.

Science activities this week included optical remote sensing (ORS) scans of Saturn's south pole as well as Ultraviolet Imaging Spectrograph mosaics of Saturn's magnetosphere. Imaging Science Subsystem (ISS) performed mosaics and movies of the rings and Saturn's south pole. Magnetospheric Imaging Instrument (MIMI) imaged the magnetosphere and observed the solar winds and pickup ions while the ORS instruments simultaneously observed Saturn's aurora. Magnetospheric and Plasma Science (MAPS) continued its campaign to study the influence of the solar wind on Saturn's aurora.

The dark material that coats one hemisphere of Saturn's moon Iapetus is very dark, as these two processed views of the same image demonstrate.

A wrap up meeting was held for the Science Operations Plan (SOP) Implementation of tour sequences S33 and S34. The products have been archived and will be available for use in April of 2007 when the S33 Aftermarket process begins. A kick-off meeting was held for SOP Implementation of S37/S38. Preliminary port #1 is scheduled for September 10. The official port for SOP Update of S06 occurred this week. The products have been merged and delivered to ACS for end-to-end pointing analysis.

The S04 Preliminary Sequence Integration and Validation-2 (PSIV) merged sequence products were published for teams to review and for ACS to use for Inertial Vector Propagator (IVP) & Kinematic Prediction Tool (KPT) inputs as part of the Science and Sequence Update Process (SSUP). In addition, instrument teams submitted their Instrument Expanded Block Spacecraft Activity Sequence Files. For S05 development, PSIV1 Cycle 1 merged files were placed in the Program file repository for team review, and a Sub-Sequence Generation sequence change request approval meeting was held.

In the last week, 578 ISS images and 130 Visual and Infrared Mapping Spectrometer (VIMS) cubes were acquired and distributed. So far since Approach Science began, 18004 ISS images and 4914 VIMS cubes have been returned.

A delivery review of Multi Mission Image Processing Laboratory software version D32 was conducted this week. No concerns were brought up and the delivery was accepted by all Projects. Instrument Operations personnel will perform certification testing prior to releasing the software for operational use by Cassini in early September.

The final scheduled release of the Cassini Information Management System(CIMS) 3.2 has been installed for operations. The CIMS developers wish the flight team a successful mission!

This week Cassini Outreach and Saturn Observation Campaign members supported the Pasadena Public Library's "Night Under The Stars" event. Sixty kids aged 5- 12 and their parents enjoyed telescopic views after dining on stars, moons and crater dip punch. During the evening the traveling "NASA @ your library" exhibit was displayed featuring one exhibit-stand with six flat-screen computers, and a plasma screen theatre showing NASA programming, in addition to mission models and more. The exhibit opened August 13, runs through September 19, and is open during all library hours.

The Cassini-Huygens mission 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, manages the Cassini-Huygens mission for NASA's Science Mission Directorate, Washington, DC. JPL designed, developed and assembled the Cassini orbiter. For the latest images and more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov/ and http://www.nasa.gov/cassini.

Contact:Carolina Martinez Jet Propulsion Laboratory, Pasadena, CAPhone: 818-354-9382

Additional articles on this subject are available at:http://www.astrobio.net/news/article1152.htmlhttp://www.astrobio.net/news/article1161.htmlhttp://cl.extm.us/?fe8f1d707c63027c75-fe28167073670175701c72http://www.spacedaily.com/news/cassini-04zzl.htmlhttp://www.spacedaily.com/news/cassini-04zzm.htmlhttp://www.spacedaily.com/news/cassini-04zzn.htmlhttp://www.spacedaily.com/news/cassini-04zzp.htmlhttp://www.spacedaily.com/news/cassini-04zzq.htmlhttp://spaceflightnow.com/cassini/040823status.htmlhttp://www.universetoday.com/am/publish/cassini_completes_orbital_maneuver.html

DEEP IMPACT UPDATEFrom Deep News

24 August 2004

Launch: December 30, 2004Impact Encounter: July 4, 2005

With less than half a year to launch, the Deep Impact mission continues testing of both the spacecraft hardware and software as they prepare for the transfer to Kennedy Space Center in Florida. It's been a busy summer for the entire team at Jet Propulsion Laboratory, Ball Aerospace and Technologies Corp and the University of Maryland where the Principal Investigator and members of his international science team held meetings. Read more about this remarkable mission to put a deep crater in a comet and find its composition and clues to the beginning of the solar system at http://deepimpact.jpl.nasa.gov or http://deepimpact.umd.edu.

Up close and personal—meet our summer interns

The mission has been making a Deep Impact on the future of engineering and science as we hosted four summer interns—one at the University of Maryland and three at Jet Propulsion Laboratory. Each student has been assigned to work some facet of the mission and as we close the summer, they share with us their excitement about space science and the Deep Impact mission. Meet Jessica, Cindy, Nick, and Julia: http://deepimpact.umd.edu/community/bio-jchavez.htmlhttp://deepimpact.umd.edu/community/bio-crich.htmlhttp://deepimpact.umd.edu/community/bio-ntaylor.htmlhttp://deepimpact.umd.edu/community/bio-jdemarines.html

Educators: new and improved activities in math and science

Did you have a restful summer? We want to send you back to school with some new and some improved activities tied to national math and science standards. An update of our Designing Craters activity was done by McREL this summer giving it a new look and adding more references. It is still the inquiry-based activity that Gretchen Walker produced. And as if that weren't enough, our team at McREL also matched our Mission Challenges to national math standards, putting them in student and teacher's guide formats. Now, your students can use math to solve real challenges that our mission team encountered. They'll have so much fun, they won't know they're learning! Designing Craters: http://deepimpact.umd.edu/designing_craters/index.htmlMission Challenges: http://deepimpact.umd.edu/disczone/challenge.html

Where is Tempel 1? Have you checked it lately?

If you haven't checked to see where Comet Tempel 1 is lately, you may want to take a look and see how much closer it is to its impact destination in July 2005 (http://deepimpact.astro.umd.edu/amateur/where_is.shtml). Remember, our amateur astronomers will be looking up into the sky to see this comet again in late 2004 and early 2005.

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http://deepimpact.astro.umd.edu/amateur/where_is.shtml

http://deepimpact.umd.edu/disczone/challenge.html

http://deepimpact.umd.edu/designing_craters/index.html

http://deepimpact.umd.edu/community/bio-jdemarines.html

http://deepimpact.umd.edu/community/bio-ntaylor.html

http://deepimpact.umd.edu/community/bio-crich.html

http://deepimpact.umd.edu/community/bio-jchavez.html

http://deepimpact.umd.edu/

http://deepimpact.jpl.nasa.gov/

http://spaceflightnow.com/cassini/040823status.html

http://www.spacedaily.com/news/cassini-04zzq.html

http://www.spacedaily.com/news/cassini-04zzp.html

http://www.spacedaily.com/news/cassini-04zzn.html

http://www.spacedaily.com/news/cassini-04zzm.html

http://www.spacedaily.com/news/cassini-04zzl.html

http://cl.extm.us/?fe8f1d707c63027c75-fe28167073670175701c72

http://www.nasa.gov/cassini

http://saturn.jpl.nasa.gov/

http://jpl.convio.net/site/R?i=PdgKRrSbsrJO-3BCLCXxIg

http://jpl.convio.net/site/R?i=PdgKRrSbsrJO-3BCLCXxIg


A model for excellence! How was the Deep Impact model born?

Deep Impact has three paper models you can download and build: the impactor only, the basic model and the detailed model with 3-D instruments. How did these models come to be? It started with a paper model made by Bill Blume at Jet Propulsion Laboratory to demonstrate the spacecraft's movements in space to the rest of the team. But where it went from there is quite a story. Meet Denise Cook-Clampert and David Lewis from Ball Aerospace and Technologies Corp., and see how our current models were born (http://deepimpact.umd.edu/disczone/excellence.html).

Did you see our past Deep News issues?

Visit http://deepimpact.umd.edu/newsletter/archive.html to catch up on exciting past news from the Deep Impact mission. The Deep Impact mission is a partnership among the University of Maryland (UMD), the California Institute of Technology's Jet Propulsion Laboratory (JPL) and Ball Aerospace and Technology Corp (BATC). Deep Impact is a NASA Discovery mission, eighth in a series of low-cost, highly focused space science investigations. See http://deepimpact.jpl.nasa.gov or our mirror site at http://deepimpact.umd.edu.

Subscription information

Send this email along to your friends. If you received this newsletter from a friend, you can subscribe at http://deepimpact.umd.edu/newsletter/signup.html.

MARS EXPLORATION ROVERS UPDATESNASA/JPL releases

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

At a rock called "Clovis," the rock abrasion tool on NASA's Mars Exploration Rover Spirit cut a 9-millimeter (0.35-inch) hole during the rover's 216th martian day, or sol (Aug. 11, 2004). The hole is the deepest drilled in a rock on Mars so far. This approximately true-color view was made from images taken by Spirit's panoramic camera on sol 226 (Aug. 21, 2004) at around 12:50 PM local true solar time–-early afternoon in Gusev Crater on Mars. To the right is a "brush flower" of circles produced by scrubbing the surface of the rock with the abrasion tool's wire brush. Scientists used rover's Mössbauer spectrometer and alpha particle X-ray spectrometer to look for iron-bearing minerals and determine the elemental chemical composition of the rock. This composite combines images taken with the camera's 600-, 530- and 480-nanometer filters. The diameter of the hole cut into the rock is 4.5 centimeters (1.8 inches). Image credit: NASA/JPL/Cornell.

Planetary scientists got excited when they saw this imagery coming in from NASA's Mars Exploration Rover Spirit because they could see hints of rock strata and other interesting geologic features ahead. In the middle of this image, from upper left to the lower right, lies a trough that resembles a small ravine. To the right of that and a little way up the hill, beyond a rock-strewn surface, sits a small rounded ridge. Fine horizontal streaks, just perceptible in this image, suggest possible layering in the bedrock. Above that are rock features that appear to drape across the slopes. Scientists are discussing whether to take the rover closer or select other interesting targets for further study. This view looks eastward from the "West Spur" of the "Columbia Hills," where Spirit has been conducting scientific investigations. It is a mosaic of several frames Spirit took with its panoramic camera on the rover's 229th martian day, or sol, (Aug. 24, 2004). The field of view is 48 degrees from left to right. The image is presented in a cylindrical projection with geometrical seam correction. Image credit: NASA/JPL/Cornell.

The intriguing dunes at the bottom of "Endurance Crater" presented a tantalizing target for the science team for NASA's Mars Exploration Rover Opportunity. After analyzing the soil near and around the dunes, however, the rover engineering team decided that it was too risky to send Opportunity any closer. The terrain between the rover and the dune tendril did not present clear evidence of rocky plates to give the rover sufficient traction. A finger-like dune tendril pictured here (left) is, essentially, pointing to the rover's current area of investigation. Opportunity rolled over the foreground rock, called "Puffin." During the past several sols the rover has been examining its new neighborhood, an area that includes the rocks "Ellesmere" and "Escher" (not pictured) and the soil targets "Shag" and "Auk" (also not pictured). Experiencing significant slippage, the rover did some unintended trenching and left deep tracks in this area. This view is a mosaic of two images taken by the rover's navigation camera on Opportunity's 206th sol on Mars (August 22, 2004) and presented in a cylindrical projection. Image credit: NASA/JPL.

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The wheel tracks in this image are an artifact of the difficult terrain faced recently by NASA's Mars Exploration Rover Opportunity deep inside "Endurance Crater." Opportunity took the picture with its navigation camera on the rover's 205th martian day, or sol (Aug. 21, 2004). On the preceding sol, to avoid a potentially hazardous rock target, the rover team changed routes. Steep slopes and lack of traction when driving in this terrain caused the rover to experience up to 50 percent slip during parts of its traverse. Opportunity ended up more than 50 centimeters (about 20 inches) downslope from the planned final position. Another shift in objective on sol 205 had Opportunity on the move again toward safer terrain. Analysis of the final drive showed the rover's traction increasing during its latest moves. Image credit: NASA/JPL.

Additional articles on this subject are available at:http://www.astrobio.net/news/article1160.htmlhttp://www.spacedaily.com/news/mars-mers-04zzzzzzw.htmlhttp://www.spacedaily.com/news/mars-mers-04zzzzzzx.htmlhttp://www.spacedaily.com/news/mars-mers-04zzzzzzy.htmlhttp://www.spacedaily.com/news/mars-mers-04zzzzzzz.html

MARS EXPRESS UPDATESESA releases

Where is Zero Degrees Longitude on Mars?19 August 2004

On Earth, the longitude of the Royal Observatory in Greenwich, England, is defined as the "prime meridian", or zero degrees longitude. Locations on Earth are measured in degrees east or west from this position, but where is the equivalent position on Mars? Earth's prime meridian was defined by international agreement in 1884 as the position of the large "transit circle", a telescope in the Royal Observatory's Meridian Building. The transit circle was built by Sir George Biddell Airy, the 7th Astronomer Royal, in 1850.

For Mars, the prime meridian was first defined by the German astronomers W. Beer and J. H. Mädler in 1830-32. They used a small circular feature on the surface, which they called "A", as a reference point to determine the rotation period of the planet. The Italian astronomer G. Schiaparelli used this feature as the zero point of longitude in his 1877 map of Mars. It was subsequently named Sinus Meridiani ("Middle Bay") by French astronomer Camille Flammarion. A crater in the Sinus Meridiani was later called Airy, named to commemorate the builder of the Greenwich transit. When the US Mariner 9 spacecraft mapped the planet at about 1 kilometer resolution in 1972, a more precise definition was needed.

The 0.5-kilometer-wide crater, subsequently named 'Airy-0' (within the larger crater Airy), chosen as the zero degrees longitude point. Here the outlines of the Mariner 9, Viking and Mars Global Surveyor images are shown on a wide-angle context image taken by the US Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC). Image credit: NASA.

Merton Davies of the RAND Corporation was analyzing surface features and designated a 0.5-kilometer-wide crater, subsequently named "Airy-0" (within the larger crater Airy) as the zero point. This crater was imaged once by Mariner 9 and once by the Viking 1 orbiter in 1978, and these two images were the basis of the martian longitude system for the rest of the 20th century. The US Mars Global Surveyor (MGS) attempted to take a picture of Airy-0 on every close overflight it made since the beginning of its mapping mission. This shows how difficult it is to hit such a small target: nine attempts were required, and the spacecraft did not pass directly over Airy-0 until almost the end of the MGS primary mission in January 2001.

Originally, a system with "planetographic" latitude and longitude increasing to the west was developed to be used with the Viking observations. The US Geological Survey and other organizations then adopted a system with "planetocentric" latitude and longitude increasing to the east for making future Mars maps and imagery. Both systems were approved for use on Mars by the International Astronomical Union in 2000. (The "planetocentric" system uses co-ordinates derived from the angle measured from the equator to a point on the surface at the center of the planet, whereas the "planetographic" system uses co-ordinates which are mapped on the surface.)

Most maps produced before 2002 use the earlier coordinates system, but now the majority of Mars missions and instrument teams have now adopted the latter system defined for Mars, namely the planetocentric latitude and east longitude system. These definitions have been widely adopted by NASA and ESA missions and other users of planetary data and are likely to remain in use for a decade or more.

The articles featuring the latest Mars images published on the ESA Mars Express web site quote positions given in this latest system, with longitude ranging from 0-360 degrees East. This is different to Earth, where we give longitudes as 0-180 degrees, East or West.

Read the original news release at http://www.esa.int/SPECIALS/Mars_Express/SEM0VQV4QWD_0.html.

Mars on Your Desktop—New Screensaver20 August 2004

Download more astonishing images of Mars in a fascinating new screensaver from ESA. This is a collection of the best 3D images to date produced by the High Resolution Stereo Camera on board ESA's Mars Express. Fifteen

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fantastic images of the surface of Mars are presented here for you to download and enjoy for yourself on your PC. Download the screensaver at http://esamultimedia.esa.int/images/marsexpress/screensaver/Mars3D.zip.

Read the original news release at http://www.esa.int/SPECIALS/Mars_Express/SEMK6XW4QWD_0.html.

Crater Dunes in Argyre Planitia23 August 2004

These images, taken by the High Resolution Stereo Camera (HRSC) on board ESA's Mars Express spacecraft, show a martian crater with a dune field on its floor. The images were taken during orbit 427 in May 2004, and show the crater with a dune field located in the north-western part of the Argyre Planitia crater basin. The images are centered at Mars longitude 303° East and latitude 43° South. The image resolution is approximately 16.2 meters per pixel. The crater is about 45 kilometers wide and 2 kilometers deep. In the north-eastern part of this crater, the complex dune field is 7 kilometers wide by 12 kilometers long.

In arid zones on Earth, these features are called "barchans", which are dunes having an asymmetrical profile, with a gentle slope on the wind-facing side and a steep slope on the lee-side. The dune field shown here suggests an easterly wind direction with its steeper western part. The composition of the dune material is not certain, but the dark sands could be of basaltic origin.

The color image has been created from the HRSC’s nadir (vertical view) and three color channels. The 3D anaglyph image has been created using the nadir and stereo channels. The perspective views have been calculated from the digital terrain model derived from the stereo channels.

Read the original news release at http://www.esa.int/SPECIALS/Mars_Express/SEMYRSW4QWD_0.html.

Eos Chasma, part of Valles MarinerisESA release, 30 August 2004

These images, taken by the High Resolution Stereo Camera (HRSC) on board ESA's Mars Express spacecraft, show the southern part of Valles Marineris, called Eos Chasma. The images were taken during orbit 533 in June 2004, and are centered at Mars longitude 322° East and latitude 11° South. The image resolution is approximately 80 meters per pixel.

Between surrounding plains and the smooth valley floor, a height difference of about 5000 meters has been measured. The plain to the south, above Eos Chasma, is covered by several impact craters with diameters of around 20 kilometers and drainage channels. To the east on this plain, isolated regions with cracked surfaces become more prominent. The direction of flow of the drainage channels in this area of the plain is ambiguous, as the channels to the north-east drain towards the south-east, and those in the south-west normally flow to the north-west.

The northern part of Eos Chasma’s valley floor is a rough area with angular hills reaching almost 1000 meters. In contrast, the southern part reveals a smooth topography with distinct flow structures. In some areas of the southern slope, at least two terrace levels can be observed. Some haze in the valley hints at the presence of aerosols (airborne microscopic dust or liquid droplets).

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The color image was created from the HRSC’s nadir (vertical view) and three color channels. The 3D anaglyph image was created using the nadir and one of the stereo channels. The perspective views, with height exaggerated by a factor of four, were calculated from the digital terrain model derived from the stereo channels. Image resolution was reduced for use on the internet.

Read the original news release at http://www.esa.int/SPECIALS/Mars_Express/SEM9MZW4QWD_0.html.

Additional articles on this subject are available at:http://www.astrobio.net/news/article1151.htmlhttp://www.spacedaily.com/news/marsexpress-04x.htmlhttp://www.spacedaily.com/news/marsexpress-04y.htmlhttp://www.universetoday.com/am/publish/martian_crater_dunes.htmlhttp://www.universetoday.com/am/publish/mars_express_eos_chasma.html

MARS GLOBAL SURVEYOR IMAGESNASA/JPL/MSSS release

19-25 August 2004

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

Polar Unconformity (Released 19 August 2004)http://www.msss.com/mars_images/moc/2004/08/19/index.html

Rabe Dunes (Released 20 August 2004)http://www.msss.com/mars_images/moc/2004/08/20/index.html

Bunge Dunes (Released 21 August 2004)http://www.msss.com/mars_images/moc/2004/08/21/index.html

Dunes and Dust Devil Tracks (Released 22 August 2004)http://www.msss.com/mars_images/moc/2004/08/22/index.html

Polar Dunes, Spotted (Released 23 August 2004)http://www.msss.com/mars_images/moc/2004/08/23/index.html

Exhumed Craters near Kaiser (Released 24 August 2004)http://www.msss.com/mars_images/moc/2004/08/24/index.html

West Olympica Fossae (Released 25 August 2004)http://www.msss.com/mars_images/moc/2004/08/25/index.html

All of the Mars Global Surveyor images are archived at http://www.msss.com/mars_images/moc/index.html.

Mars Global Surveyor was launched in November 1996 and has been in Mars orbit since September 1997. It began its primary mapping mission on March 8, 1999. Mars Global Surveyor is the first mission in a long-term program of Mars exploration known as the Mars Surveyor Program that is managed by JPL for NASA's Office of Space Science, Washington, DC. Malin Space Science Systems (MSSS) and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

MARS ODYSSEY BEGINS OVERTIME AFTER SUCCESSFUL MISSIONNASA/JPL release 2004-209

25 August 2004

NASA's Mars Odyssey orbiter begins working overtime today after completing a prime mission that discovered vast supplies of frozen water, ran a safety check for future astronauts, and mapped surface textures and minerals all over Mars, among other feats.

"Odyssey has accomplished all of its mission-success criteria," said Dr. Philip Varghese, project manager for Odyssey at NASA's Jet Propulsion Laboratory, Pasadena, CA. The spacecraft has been examining Mars in detail since February 2002, more than a full Mars year of about 23 Earth months. NASA has approved an extended mission through September 2006.

"This extension gives us another martian year to build on what we have already learned," said JPL's Dr. Jeff Plaut, project scientist for Odyssey. "One goal is to look for climate change. During the prime mission we tracked dramatic seasonal changes, such as the comings and goings of polar ice, clouds and dust storms. Now, we have begun watching for year-to-year differences at the same time of year."

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The extension will also continue Odyssey's support for other Mars missions. About 85 percent of images and other data from NASA's twin Mars rovers, Spirit and Opportunity, have reached Earth via communications relay by Odyssey, which receives transmissions from both rovers every day. The orbiter helped analyze potential landing sites for the rovers and is doing the same for NASA's Phoenix mission, scheduled to land on Mars in 2008. Plans call for Odyssey to aid NASA's Mars Reconnaissance Orbiter, due to reach Mars in March 2006, by monitoring atmospheric conditions during months when the newly arrived orbiter uses calculated dips into the atmosphere to alter its orbit into the desired shape.

Odyssey was launched April 7, 2001, and used the same dips into the atmosphere, known as aerobraking, to shape its orbit during the initial months after it reached Mars on October 23, 2001. The spacecraft carries three research systems: a camera system made up of infrared and visible-light sensors; a spectrometer suite with a gamma ray spectrometer, a neutron spectrometer and a high-energy neutron detector; and a radiation environment detector.

This map shows the estimated lower limit of the water content of the upper meter of martian soil.

Less than a month after the science mapping campaign began, the team announced a major discovery. The gamma ray and neutron instruments detected copious hydrogen just under Mars' surface in the planet's south polar region. Researchers interpret the hydrogen as frozen water—enough within about a meter (3 feet) of the surface, if the ice were melted, to fill Lake Michigan a couple times.

Here are a few of Odyssey's other important accomplishments so far: As summer came to northern Mars and the north polar covering of

frozen carbon dioxide shrank, Odyssey found abundant frozen water in the north, too.

Infrared mapping showed that a mineral called olivine is widespread. This indicated the environment has been quite dry, because water exposure alters olivine into other minerals.

Findings indicated the amount of frozen water in some relatively warm regions on Mars is too great to be in equilibrium with the atmosphere, suggesting that Mars may be going through a period of climate change.

Features visible near small, young gullies in some Odyssey images may be slowly melting snowpacks left over from a martian ice age.

The first experiment sent to Mars specifically in preparation for human missions found that radiation levels around Mars, from solar flares and cosmic rays, are two to three times higher than around Earth.

Odyssey's camera system obtained the most detailed complete global maps of Mars ever, with daytime and nighttime infrared images at a resolution of 100 meters (328 feet).

"We've accomplished everything we set out to do, and more," said JPL's Robert Mase, Odyssey mission manager. Although an unusually powerful solar flare in October 2003 knocked out the radiation environment instrument, Odyssey is otherwise in excellent health. The spacecraft has enough fuel onboard to keep operating through this decade and the next at current consumption rates. The mission extension, with a budget of $35 million, essentially doubles the science payoff from Odyssey for less than one-eighth of the mission's original $297 million cost.

Artist's concept of Odyssey orbiting Mars.

JPL, a division of the California Institute of Technology, Pasadena, manages Mars Odyssey for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, built and operates the spacecraft. Investigators at Arizona State University, Tempe; University of Arizona, Tucson; NASA's Johnson Space Center, Houston; the Russian Aviation and Space Agency, Moscow; and Los Alamos National Laboratory, Los Alamos, NM, built and operate Odyssey science instruments. For more information about Miars Odyssey on the Internet, visit http://mars.jpl.nasa.gov/odyssey.

Contacts:Guy WebsterJet Propulsion Laboratory, Pasadena, CAPhone: 818-354-6278

Gretchen Cook-AndersonNASA Headquarters, Washington, DCPhone: 202-358-0836

Additional articles on this subject are available at:http://www.astrobio.net/news/article1159.htmlhttp://www.space.com/missionlaunches/odyssey_update_040826.htmlhttp://www.spacedaily.com/news/mars-odyssey-04b.htmlhttp://www.spacedaily.com/news/mars-odyssey-04c.htmlhttp://www.universetoday.com/am/publish/mars_odyssey_goes_into_overtime.html

MARS ODYSSEY THEMIS IMAGES23-27 August 2004

Apollinaris Patera (Released 23 August 2004)http://themis.la.asu.edu/zoom-20040823A.html

Acheron Catena (Released 24 August 2004)http://themis.la.asu.edu/zoom-20040824a.html

Ares Vallis (Released 25 August 2004)http://themis.la.asu.edu/zoom-20040825A.html

Gordii Dorsa (Released 26 August 2004)http://themis.la.asu.edu/zoom-20040826A.html

Scylla Scopulus (Released 27 August 2004)http://themis.la.asu.edu/zoom-20040827A.html

All of the THEMIS images are archived at http://themis.la.asu.edu/latest.html.

NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, DC. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at

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http://www.spacedaily.com/news/mars-odyssey-04c.html

http://www.spacedaily.com/news/mars-odyssey-04b.html

http://www.space.com/missionlaunches/odyssey_update_040826.html

http://mars.jpl.nasa.gov/odyssey


Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

ROSETTA: LGA THRESHOLD TEST SUCCESSFUL (REPORT FOR 6 TO 20 AUGUST)ESA release

23 August 2004

In the reporting period the spacecraft was monitored weekly, mainly to dump the telemetry stored on-board. During the last weekly pass, the LGA threshold test first attempted on 1 June 2004 was repeated successfully (see report #15). At the end of the last New Norcia pass in the reporting period (DOY 233) Rosetta was at 75.6 million kilometers from the Earth. The one-way signal travel time was 4 minutes and 12 seconds.

Read the original news release at http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=35706.

End Marsbugs, Volume 11, Number 34.

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