NASA Spacecraft Sees Ice on Mars Exposed by Meteor Impacts

RJ Note: Cool.

/PRNewswire/ -- NASA's Mars Reconnaissance Orbiter has revealed frozen water hiding just below the surface of mid-latitude Mars. The spacecraft's observations were obtained from orbit after meteorites excavated fresh craters on the Red Planet.

Scientists controlling instruments on the orbiter found bright ice exposed at five Martian sites with new craters that range in depth from approximately 1.5 feet to 8 feet. The craters did not exist in earlier images of the same sites. Some of the craters show a thin layer of bright ice atop darker underlying material. The bright patches darkened in the weeks following initial observations, as the freshly exposed ice vaporized into the thin Martian atmosphere. One of the new craters had a bright patch of material large enough for one of the orbiter's instruments to confirm it is water ice.

The finds indicate water ice occurs beneath Mars' surface halfway between the north pole and the equator, a lower latitude than expected in the Martian climate.

"This ice is a relic of a more humid climate from perhaps just several thousand years ago," said Shane Byrne of the University of Arizona.

Byrne is a member of the team operating the orbiter's High Resolution Imaging Science Experiment, or HiRISE camera, which captured the unprecedented images. Byrne and 17 co-authors report the findings in the Sept. 25 edition of the journal Science.

"We now know we can use new impact sites as probes to look for ice in the shallow subsurface," said Megan Kennedy of Malin Space Science Systems in San Diego, a co-author of the paper and member of the team operating the orbiter's Context Camera.

During a typical week, the Context Camera returns more than 200 images of Mars that cover a total area greater than California. The camera team examines each image, sometimes finding dark spots that fresh, small craters make in terrain covered with dust. Checking earlier photos of the same areas can confirm a feature is new. The team has found more than 100 fresh impact sites, mostly closer to the equator than the ones that revealed ice.

An image from the camera on Aug. 10, 2008, showed apparent cratering that occurred after an image of the same ground was taken 67 days earlier. The opportunity to study such a fresh impact site prompted a look by the orbiter's higher resolution camera on Sept. 12, 2009, confirming a cluster of small craters.

"Something unusual jumped out," Byrne said. "We observed bright material at the bottoms of the craters with a very distinct color. It looked a lot like ice."

The bright material at that site did not cover enough area for a spectrometer instrument on the orbiter to determine its composition. However, a Sept. 18, 2008, image of a different mid-latitude site showed a crater that had not existed eight months earlier. This crater had a larger area of bright material.

"We were excited about it, so we did a quick-turnaround observation," said co-author Kim Seelos of Johns Hopkins University Applied Physics Laboratory in Laurel, Md., "Everyone thought it was water ice, but it was important to get the spectrum for confirmation."

The Mars orbiter is designed to facilitate coordination and quick response by the science teams, making it possible to detect and understand rapidly changing features. The ice exposed by fresh impacts suggests that NASA's Viking 2 lander, digging into mid-latitude Mars in 1976, might have struck ice if it had dug four inches deeper.

The Viking 2 mission, which consisted of an orbiter and a lander, launched in September 1975 and became one of the first two space probes to land successfully on the Martian surface. The Viking 1 and 2 landers characterized the structure and composition of the atmosphere and surface. They also conducted on-the-spot biological tests for life on another planet.

NASA's Jet Propulsion Laboratory in Pasadena manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate in Washington. Lockheed Martin Space Systems in Denver built the spacecraft. The Context Camera was built and is operated by Malin. The University of Arizona operates the HiRISE camera, which Ball Aerospace & Technologies Corp., in Boulder, Colo., built. The Johns Hopkins University Applied Physics Laboratory led the effort to build the Compact Reconnaissance Imaging Spectrometer and operates it in coordination with an international team of researchers.

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NASA Astronaut Tweets Provide Inside Look at Mission Training

RJ Note: This is pretty neat stuff. Of course, you can also follow the Georgia Front Page on Twitter at @GAFrontPage.

/PRNewswire- / -- NASA astronaut Mike Massimino is using Twitter to provide a unique, behind the scenes peek at the last weeks of his training for the fifth and final shuttle servicing mission to NASA's Hubble Space Telescope.

Massimino, whose Twitter username is Astro_Mike (@Astro_Mike), will fly aboard space shuttle Atlantis as a mission specialist and spacewalker during the STS-125 mission, targeted to launch May 12. Atlantis' 11-day flight will include five spacewalks to refurbish and upgrade Hubble with state-of-the-art science instruments. After the astronaut's visit, Hubble's capabilities will be expanded and its lifetime extended through at least 2014.

This will be Massimino's second trip to space. He first flew on the STS-109 mission to Hubble in 2002. During that flight, he performed two spacewalks.

Along with Massimino, the crew of Atlantis includes Commander Scott Altman, Pilot Gregory C. Johnson and Mission Specialists Andrew Feustel, Michael Good, John Grunsfeld and Megan McArthur.

To follow Massimino's Twitter, visit:

http://twitter.com/Astro_Mike


Follow NASA mission activities on Twitter @NASA, and for a complete list of all agency missions on Twitter, visit:


http://www.nasa.gov/collaborate

For information about the STS-125 mission and its crew, visit:

http://www.nasa.gov/shuttle

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NASA Researchers Find Clues to a Secret of Life

/PRNewswire-USNewswire/ -- NASA scientists analyzing the dust of meteorites have discovered new clues to a long-standing mystery about how life works on its most basic, molecular level.

"We found more support for the idea that biological molecules, like amino acids, created in space and brought to Earth by meteorite impacts help explain why life is left-handed," said Dr. Daniel Glavin of NASA's Goddard Space Flight Center in Greenbelt, Md. "By that I mean why all known life uses only left-handed versions of amino acids to build proteins." Glavin is lead author of a paper on this research appearing in the Proceedings of the National Academy of Sciences March 16.

Proteins are the workhorse molecules of life, used in everything from structures like hair to enzymes, the catalysts that speed up or regulate chemical reactions. Just as the 26 letters of the alphabet are arranged in limitless combinations to make words, life uses 20 different amino acids in a huge variety of arrangements to build millions of different proteins. Amino acid molecules can be built in two ways that are mirror images of each other, like your hands. Although life based on right-handed amino acids would presumably work fine, "you can't mix them," says Dr. Jason Dworkin of NASA Goddard, co-author of the study. "If you do, life turns to something resembling scrambled eggs -- it's a mess. Since life doesn't work with a mixture of left-handed and right-handed amino acids, the mystery is: how did life decide -- what made life choose left-handed amino acids over right-handed ones?"

Over the last four years, the team carefully analyzed samples of meteorites with an abundance of carbon, called carbonaceous chondrites. The researchers looked for the amino acid isovaline and discovered that three types of carbonaceous meteorites had more of the left-handed version than the right-handed variety -- as much as a record 18 percent more in the often-studied Murchison meteorite. "Finding more left-handed isovaline in a variety of meteorites supports the theory that amino acids brought to the early Earth by asteroids and comets contributed to the origin of only left-handed based protein life on Earth," said Glavin.

All amino acids can switch from left-handed to right, or the reverse, by chemical reactions energized with radiation or temperature, according to the team. The scientists looked for isovaline because it has the ability to preserve its handedness for billions of years, and it is extremely rarely used by life, so its presence in meteorites is unlikely to be from contamination by terrestrial life. "The meteorites we studied are from before Earth formed, over 4.5 billion years ago," said Glavin. "We believe the same process that created extra left-handed isovaline would have created more left-handed versions of the other amino acids found in these meteorites, but the bias toward left-handed versions has been mostly erased after all this time."

The team's discovery validates and extends the research first reported a decade ago by Drs. John Cronin and Sandra Pizzarello of Arizona State University, who were first to discover excess isovaline in the Murchison meteorite, believed to be a piece of an asteroid. "We used a different technique to find the excess, and discovered it for the first time in the Orgueil meteorite, which belongs to another meteorite group believed to be from an extinct comet," said Glavin.

The team also found a pattern to the excess. Different types of meteorites had different amounts of water, as determined by the clays and water-bearing minerals found in the meteorites. The team discovered meteorites with more water also had greater amounts of left-handed isovaline. "This gives us a hint that the creation of extra left-handed amino acids had something to do with alteration by water," said Dworkin. "Since there are many ways to make extra left-handed amino acids, this discovery considerably narrows down the search."

If the bias toward left-handedness originated in space, it makes the search for extraterrestrial life in our solar system more difficult, while also making its origin a bit more likely, according to the team. "If we find life anywhere else in our solar system, it will probably be microscopic, since microbes can survive in extreme environments," said Dworkin. "One of the biggest problems in determining if microscopic life is truly extra-terrestrial is making sure the sample wasn't contaminated by microbes brought from Earth. If we find the life is based on right-handed amino acids, then we know for sure it isn't from Earth. However, if the bias toward left-handed amino acids began in space, it likely extends across the solar system, so any life we may find on Mars, for example, will also be left-handed. On the other hand, if there is a mechanism to choose handedness before life emerges, it is one less problem prebiotic chemistry has to solve before making life. If it was solved for Earth, it probably has been solved for the other places in our solar system where the recipe for life might exist, such as beneath the surface of Mars, or in potential oceans under the icy crust of Europa and Enceladus, or on Titan."

The research was funded by the NASA Astrobiology Institute, the NASA Cosmochemistry program, and the NASA Astrobiology: Exobiology, and Evolutionary Biology program.

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Discovery of Methane Reveals Mars is Not a Dead Planet

/PRNewswire-USNewswire/ -- A team of NASA and university scientists has achieved the first definitive detection of methane in the atmosphere of Mars. This discovery indicates the planet is either biologically or geologically active.

The team found methane in the Martian atmosphere by carefully observing the planet throughout several Mars years with NASA's Infrared Telescope Facility and the W.M. Keck telescope, both at Mauna Kea, Hawaii. The team used spectrometers on the telescopes to spread the light into its component colors, as a prism separates white light into a rainbow. The team detected three spectral features called absorption lines that together are a definitive signature of methane.

"Methane is quickly destroyed in the Martian atmosphere in a variety of ways, so our discovery of substantial plumes of methane in the northern hemisphere of Mars in 2003 indicates some ongoing process is releasing the gas," said Michael Mumma of NASA's Goddard Space Flight Center in Greenbelt, Md. "At northern mid-summer, methane is released at a rate comparable to that of the massive hydrocarbon seep at Coal Oil Point in Santa Barbara, Calif." Mumma is lead author of a paper describing this research that will appear in Science Express on Thursday.

Methane, four atoms of hydrogen bound to a carbon atom, is the main component of natural gas on Earth. Astrobiologists are interested in these data because organisms release much of Earth's methane as they digest nutrients. However, other purely geological processes, like oxidation of iron, also release methane.

"Right now, we do not have enough information to tell whether biology or geology -- or both -- is producing the methane on Mars," Mumma said. "But it does tell us the planet is still alive, at least in a geologic sense. It is as if Mars is challenging us, saying, 'hey, find out what this means.'"

If microscopic Martian life is producing the methane, it likely resides far below the surface where it is warm enough for liquid water to exist. Liquid water is necessary for all known forms of life, as are energy sources and a supply of carbon.

"On Earth, microorganisms thrive about 1.2 to 1.9 miles beneath the Witwatersrand basin of South Africa, where natural radioactivity splits water molecules into molecular hydrogen and oxygen," Mumma said. "The organisms use the hydrogen for energy. It might be possible for similar organisms to survive for billions of years below the permafrost layer on Mars, where water is liquid, radiation supplies energy, and carbon dioxide provides carbon. Gases, like methane, accumulated in such underground zones might be released into the atmosphere if pores or fissures open during the warm seasons, connecting the deep zones to the atmosphere at crater walls or canyons."

It is possible a geologic process produced the Martian methane, either now or eons ago. On Earth, the conversion of iron oxide into the serpentine group of minerals creates methane, and on Mars this process could proceed using water, carbon dioxide and the planet's internal heat. Although there is no evidence of active volcanism on Mars today, ancient methane trapped in ice cages called clathrates might be released now.

"We observed and mapped multiple plumes of methane on Mars, one of which released about 19,000 metric tons of methane," said co-author Geronimo Villanueva of the Catholic University of America in Washington. "The plumes were emitted during the warmer seasons, spring and summer, perhaps because ice blocking cracks and fissures vaporized, allowing methane to seep into the Martian air."

According to the team, the plumes were seen over areas that show evidence of ancient ground ice or flowing water. Plumes appeared over the Martian northern hemisphere regions such as east of Arabia Terra, the Nili Fossae region, and the south-east quadrant of Syrtis Major, an ancient volcano about 745 miles across.

One method to test whether life produced this methane is by measuring isotope ratios. Isotopes of an element have slightly different chemical properties, and life prefers to use the lighter isotopes. A chemical called deuterium is a heavier version of hydrogen. Methane and water released on Mars should show distinctive ratios for isotopes of hydrogen and carbon if life was responsible for methane production. It will take future missions, like NASA's Mars Science Laboratory, to discover the origin of the Martian methane.

The research was funded by the Planetary Astronomy Program at NASA Headquarters in Washington and the Astrobiology Institute at NASA's Ames Research Center in Moffett Field, Calif. The University of Hawaii manages NASA's Infrared Telescope Facility.

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Mars Rovers Near Five Years of Science and Discovery

/PRNewswire-USNewswire/ -- NASA rovers Spirit and Opportunity may still have big achievements ahead as they approach the fifth anniversaries of their memorable landings on Mars.

Of the hundreds of engineers and scientists who cheered at NASA's Jet Propulsion Laboratory (JPL), in Pasadena, Calif., on Jan. 3, 2004, when Spirit landed safely, and 21 days later when Opportunity followed suit, none predicted the team would still be operating both rovers in 2009.

"The American taxpayer was told three months for each rover was the prime mission plan," said Ed Weiler, associate administrator for NASA's Science Mission Directorate at NASA Headquarters in Washington. "The twins have worked almost 20 times that long. That's an extraordinary return of investment in these challenging budgetary times."

The rovers have made important discoveries about wet and violent environments on ancient Mars. They also have returned a quarter-million images, driven more than 13 miles, climbed a mountain, descended into craters, struggled with sand traps and aging hardware, survived dust storms, and relayed more than 36 gigabytes of data via NASA's Mars Odyssey orbiter. To date, the rovers remain operational for new campaigns the team has planned for them.

"These rovers are incredibly resilient considering the extreme environment the hardware experiences every day," said John Callas, JPL project manager for Spirit and Opportunity. "We realize that a major rover component on either vehicle could fail at any time and end a mission with no advance notice, but on the other hand, we could accomplish the equivalent duration of four more prime missions on each rover in the year ahead."

Occasional cleaning of dust from the rovers' solar panels by Martian wind has provided unanticipated aid to the vehicles' longevity. However, it is unreliable aid. Spirit has not had a good cleaning for more than 18 months. Dust-coated solar panels barely provided enough power for Spirit to survive its third southern-hemisphere winter, which ended in December.

"This last winter was a squeaker for Spirit," Callas said. "We just made it through."

With Spirit's energy rising for spring and summer, the team plans to drive the rover to a pair of destinations about 200 yards south of the site where Spirit spent most of 2008. One is a mound that might yield support for an interpretation that a plateau Spirit has studied since 2006, called Home Plate, is a remnant of a once more-extensive sheet of explosive volcanic material. The other destination is a house-size pit called Goddard.

"Goddard doesn't look like an impact crater," said Steve Squyres of Cornell University, in Ithaca, N.Y. Squyres is principal investigator for the rover science instruments. "We suspect it might be a volcanic explosion crater, and that's something we haven't seen before."

A light-toned ring around the inside of the pit might add information about a nearby patch of bright, silica-rich soil that Squyres counts as Spirit's most important discovery so far. Spirit churned up the silica in mid-2007 with an immobile wheel that the rover has dragged like an anchor since it quit working in 2006. The silica was likely produced in an environment of hot springs or steam vents.

For Opportunity, the next major destination is Endeavour Crater. It is approximately 14 miles in diameter, more than 20 times larger than another impact crater, Victoria, where Opportunity spent most of the past two years. Although Endeavour is 7 miles from Victoria, it is considerably farther as the rover drives on a route evading major obstacles.

Since climbing out of Victoria four months ago, Opportunity has driven more than a mile of its route toward Endeavour and stopped to inspect the first of several loose rocks the team plans to examine along the way. High-resolution images from NASA's Mars Reconnaissance Orbiter, which reached Mars in 2006, are helping the team plot routes around potential sand traps that were not previously discernable from orbit.

"The journeys have been motivated by science, but have led to something else important," said Squyres. "This has turned into humanity's first overland expedition on another planet. When people look back on this period of Mars exploration decades from now, Spirit and Opportunity may be considered most significant not for the science they accomplished, but for the first time we truly went exploring across the surface of Mars."

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Biggest Breach of Earth's Solar Storm Shield Discovered

/PRNewswire-USNewswire/ -- Earth's magnetic field, which shields our planet from particles streaming outward from the Sun, often develops two holes that allow the largest leaks, according to researchers sponsored by NASA and the National Science Foundation.

"The discovery overturns a long-standing belief about how and when most of the solar particles penetrate Earth's magnetic field, and could be used to predict when solar storms will be severe. Based on these results, we expect more severe storms during the upcoming solar cycle," said Vassilis Angelopoulos of the University of California, Los Angeles, Principal Investigator for NASA's THEMIS mission (Time History of Events and Macroscale Interactions during Substorms). THEMIS was used to discover the size of the leak.

Earth's magnetic field acts as a shield against the bombardment of particles continuously streaming from the sun. Because the solar particles (ions and electrons) are electrically charged, they feel magnetic forces and most are deflected by our planet's magnetic field. However, our magnetic field is a leaky shield and the number of particles breaching this shield depends on the orientation of the sun's magnetic field. It had been thought that when the sun's magnetic field is aligned with that of the Earth, the door is shut and that few if any solar particles enter Earth's magnetic shield. The door was thought to open up when the solar magnetic field direction points opposite to Earth's field, leading to more solar particles inside the shield.

Surprisingly, recent observations by the THEMIS spacecraft fleet demonstrate that the opposite is true. "Twenty times more solar particles cross the Earth's leaky magnetic shield when the sun's magnetic field is aligned with that of the Earth compared to when the two magnetic fields are oppositely directed," said Marit Oieroset of the University of California, Berkeley, lead author of one of two papers on this research, published May 2008 in Geophysical Research Letters.

Researchers have long suspected that this "closed door" entry mechanism might exist, but didn't know how important it was. "It's as if people knew there was a crack in a levy, but they did not know how much flooding it caused," said Oieroset.

Previous spacecraft could only sample a small part of this enormous layer of solar particles inside the Earth's magnetic shield, but the five spacecraft in the THEMIS fleet spanned the entire rapidly-growing layer to give definitive measurements.

While the THEMIS researchers discovered the size of the leak, they didn't know its location(s). This was discovered by Wenhui Li of the University of New Hampshire, Durham, N.H., and his team. They used a computer simulation to discover where two holes frequently develop in Earth's magnetic field, one at high latitude over the Northern hemisphere, and one at high latitude over the Southern hemisphere. The holes form over the daylit side of Earth, on the side of the magnetic shield facing the sun.

The simulation also showed how the leaks develop. As solar particles flow out from the sun, they carry solar magnetic fields past our planet. Li's team realized that the solar magnetic field drapes against Earth's field as it passes by. Even though the two fields point in the same direction at equatorial latitudes, they point in opposite directions at high latitudes. When compression forces the opposite fields together, they link up with each other in a process called magnetic reconnection. This process tears the two holes in Earth's magnetic field and appends the section of the solar field between the two holes to Earth's field, carrying the solar particles on this section into the magnetosphere, according to Li's team. "We've found if the door is closed, the sun tears down a wall. The crack is huge -- about four times wider than Earth and more than seven Earth diameters long," said Li, whose paper will be published in an upcoming article of the Journal of Geophysical Research.

Solar particles by themselves don't cause severe space weather, but they get energized when the solar magnetic field becomes oppositely-directed to Earth's and reconnects in a different way. The energized particles then cause magnetic storms that can overload power lines with excess current, causing widespread blackouts. The particles also can cause radiation storms that present hazards to spacecraft in high orbits and astronauts passing through the storms on the way to the moon or other destinations in the solar system. "The more particles, the more severe the storm," said Joachim "Jimmy" Raeder of the University of New Hampshire, a co-author of Li's paper. "If the solar field has been aligned with the Earth's for a while, we now know Earth's field is heavily loaded with solar particles and primed for a strong storm. This discovery gives us a basic predictive capability for the severity of solar storms, similar to a hurricane forecaster's realization that warmer oceans set the stage for more intense hurricanes. In fact, we expect stronger storms in the upcoming solar cycle. The sun's magnetic field changes direction every cycle, and due to its new orientation in the upcoming cycle, we expect the clouds of particles ejected from the sun will have a field which is at first aligned with Earth, then becomes opposite as the cloud passes by."

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NASA Supercomputer Shows How Dust Rings Point to Exo-Earths

RJ Note: We've all spent time just gazing at the stars in the heavens above. It's pretty incredible just thinking what the future of space may hold for us.

PRNewswire-USNewswire/ -- Supercomputer simulations of dusty disks around sunlike stars show that planets nearly as small as Mars can create patterns that future telescopes may be able to detect. The research points to a new avenue in the search for habitable planets.

"It may be a while before we can directly image earthlike planets around other stars but, before then, we'll be able to detect the ornate and beautiful rings they carve in interplanetary dust," says Christopher Stark, the study's lead researcher at the University of Maryland, College Park.

Working with Marc Kuchner at NASA's Goddard Space Flight Center in Greenbelt, Md., Stark modeled how 25,000 dust particles responded to the presence of a single planet -- ranging from the mass of Mars to five times Earth's -- orbiting a sunlike star. Using NASA's Thunderhead supercomputer at Goddard, the scientists ran 120 different simulations that varied the size of the dust particles and the planet's mass and orbital distance.

"Our models use ten times as many particles as previous simulations. This allows us to study the contrast and shapes of ring structures," Kuchner adds. From this data, the researchers mapped the density, brightness, and heat signature resulting from each set of parameters.

"It isn't widely appreciated that planetary systems -- including our own -- contain lots of dust," Stark adds. "We're going to put that dust to work for us."

Much of the dust in our solar system forms inward of Jupiter's orbit, as comets crumble near the sun and asteroids of all sizes collide. The dust reflects sunlight and sometimes can be seen as a wedge-shaped sky glow -- called the zodiacal light -- before sunrise or after sunset.

The computer models account for the dust's response to gravity and other forces, including the star's light. Starlight exerts a slight drag on small particles that makes them lose orbital energy and drift closer to the star.

"The particles spiral inward and then become temporarily trapped in resonances with the planet," Kuchner explains. A resonance occurs whenever a particle's orbital period is a small-number ratio -- such as two-thirds or five-sixths -- of the planet's.

For example, if a dust particle makes three orbits around its star every time the planet completes one, the particle repeatedly will feel an extra gravitational tug at the same point in its orbit. For a time, this extra nudge can offset the drag force from starlight and the dust can settle into subtle ring-like structures.

"The particles spiral in toward the star, get trapped in one resonance, fall out of it, spiral in some more, become trapped in another resonance, and so on," Kuchner says. Accounting for the complex interplay of forces on tens of thousands of particles required the mathematical horsepower of a supercomputer.

Some scientists note that the presence of large amounts of dust could present an obstacle to directly imaging earthlike planets. Future space missions -- such as NASA's James Webb Space Telescope, now under construction and scheduled for launch in 2013, and the proposed Terrestrial Planet Finder -- will study nearby stars with dusty disks. The models created by Stark and Kuchner give astronomers a preview of dust structures that signal the presence of otherwise hidden worlds.

"Our catalog will help others infer a planet's mass and orbital distance, as well as the dominant particle sizes in the rings," Stark says.

Stark and Kuchner published their results in the October 10 issue of The Astrophysical Journal. Stark has made his atlas of exo-zodiacal dust simulations available online.

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