Category: Mars

Crater Holden and Uzboi Vallis. Image credit: ESA/DLR/FU Berlin. Click to enlarge
Over the coming decade, NASA should develop and implement new methods and requirements to detect and eliminate microorganisms on robotic spacecraft sent to Mars to prevent possible contamination of the planet, says a new report from the National Academies’ National Research Council. If microbes aboard a spacecraft were to survive the trip to Mars and grow there, they could interfere with scientific investigations to detect any life that might be native to Mars. Existing techniques for cleaning spacecraft are outdated and typically eliminate only a fraction of microorganisms, said the committee that wrote the report.

Recent scientific findings suggest that liquid water could be present at many locations on Mars and that some organisms on Earth might survive in extreme, Mars-like conditions — such as very low temperatures and high salt concentrations. These discoveries have bolstered the case that Mars could be — or have been — hospitable to life and have created urgency to update policies and practices to prevent Mars contamination, the report says.

“Ongoing Mars missions have shown that the planet may have environments where some Earth microbes could grow,” said Christopher F. Chyba, committee chair and professor of astrophysics and international affairs at Princeton University, Princeton, N.J. “Although we don’t know for sure if this could happen, we need to understand whether liquid water exists in Martian near-surface environments, as well as the nature of microorganisms that are in our clean rooms and spacecraft. It will take a while to carry out the needed research and development, so we need to start in earnest now.”

NASA currently uses screening techniques that detect heat-resistant and spore-forming bacteria on spacecraft and then reduces their numbers by cleaning the spacecraft and, in certain circumstances, baking components with dry heat. But these screening methods are not designed to give a comprehensive tally of the microbes present on the spacecraft, and dry heat can be applied only to spacecraft materials that can withstand high temperatures, the report notes.

NASA should sponsor new research efforts aimed at preventing Mars contamination, the committee said, such as new techniques for detecting biological molecules that do not require time for growing laboratory cultures and could speed spacecraft sterilization and assembly in clean rooms. Also, methods that determine genetic sequences of organisms and link them to known microbial species could allow NASA to tailor sterilization techniques toward spacecraft contaminants of greatest concern. NASA should also investigate alternative cleaning methods — such as the use of radiation or vapor disinfectants — for their effectiveness in killing different types of microorganisms and for their effects on various spacecraft materials.

NASA should develop a certification process to compare detection and cleaning methods and select the most promising ones, begin testing and validating improved techniques within the next three years, and fully implement selected new techniques in time for spacecraft to launch in 2016. Until NASA conducts the research needed to transition to a modern approach for planetary protection, the agency should apply more stringent sterilization levels to all Mars landing spacecraft, the committee said. An independent review panel should be created by NASA and meet every three years to review new knowledge about the Martian environment and recommend updates, as needed, to Mars protection requirements.

The study was sponsored by NASA. The National Research Council is the principal operating arm of the National Academy of Sciences and the National Academy of Engineering. It is a private, nonprofit institution that provide science and technology advice under a congressional charter. A committee roster follows.

Original Source: The National Academies News Release

A section of the ALH84001 Mars meteorite. Image credit: NASA/JPL. Click to enlarge
The current mean temperature on the equator of Mars is a blustery -69 degrees Fahrenheit. Scientists have long thought that the Red Planet was once temperate enough for water to have existed on the surface and perhaps for life to have evolved there. But a new study by MIT and Caltech scientists gives this idea the cold shoulder.

In the July 22 issue of the journal Science, MIT Assistant Professor Benjamin Weiss and California Institute of Technology graduate student David Shuster report that their studies of martian meteorites demonstrate that at least several rocks originally located near the surface of Mars have been freezing cold for 4 billion years.

Their work is a novel approach to extracting information on the past climate of Mars through the study of martian meteorites.

In fact, the evidence suggests that during the last 4 billion years, Mars has never been sufficiently warm for liquid water to have flowed on the surface for extended periods of time. Mars therefore has probably never had an environment hospitable to the evolution of life–unless life got started during the first half-billion years of its existence, when the planet was probably warmer.

The work involves two of the seven known “nakhlite” meteorites (named after El Nakhla, Egypt, where the first such meteorite was discovered), and the celebrated ALH84001 meteorite that some scientists believe shows evidence of microbial activity on Mars. Using geochemical techniques, Shuster and Weiss reconstructed a “thermal history” for each of the meteorites to estimate the maximum long-term average temperatures to which they were subjected.

“We looked at meteorites in two ways,” said Weiss, of MIT’s Department of Earth, Atmospheric and Planetary Sciences. “First, we evaluated what the meteorites could have experienced during ejection from Mars, 11-to-15 million years ago, in order to set an upper limit on the temperatures in a worst-case scenario for shock heating.”

They concluded that ALH84001 could never have been heated to a temperature higher than 650 degrees Fahrenheit for even a brief period of time during the last 15 million years. The nakhlites, which show very little evidence of shock damage, were unlikely to have been above the boiling point of water during ejection 11 million years ago.

Those temperatures are still rather high, but the researchers also looked at the rocks’ long-term thermal history on Mars. For this, the scientists estimated the total amount of argon still remaining in the samples using data previously published by two teams at the University of Arizona and NASA’s Johnson Space Center.

Argon gas is present in the meteorites as well as in many rocks on Earth as a natural consequence of the radioactive decay of potassium. As a noble gas, argon is not very chemically reactive, and because the decay rate is precisely known, geologists for years have dated rocks by measuring their argon content.

However, argon is also known to “leak” out of rocks at a temperature-dependent rate. This means that if the argon remaining in the rocks is measured, an inference can be made about the maximum heat to which the rock has been subjected since the argon was first made. The cooler the rock has been, the more argon it will have retained.

Shuster and Weiss’s analysis found that only a tiny fraction of the argon that was originally produced in the meteorite samples has been lost through the eons. “The small amount of argon loss that has apparently taken place in these meteorites is remarkable. Any way we look at it, these rocks have been cold for a very long time,” says Shuster. Their calculations suggest that the martian surface has been in a deep freeze for most of the last 4 billion years.

“The temperature histories of these two planets are truly different. On Earth, you couldn’t find a single rock that has been below even room temperature for that long,” says Shuster. The ALH84001 meteorite, in fact, couldn’t have been above freezing for more than a million years during the last 3.5 billion years of history.

“Our research doesn’t mean that there weren’t pockets of isolated water in geothermal springs for long periods of time, but suggests instead that there haven’t been large areas of freestanding water for 4 billion years.

“Our results seem to imply that surface features indicating the presence and flow of liquid water formed over relatively short time periods,” says Shuster.

On a positive note for astrobiology, however, Weiss says the new study does nothing to disprove the theory of “panspermia,” which holds that life can jump from one planet to another by meteorites. While at Caltech as a graduate student several years ago, Weiss and his supervising professor, Joseph Kirschvink, showed that microbes could indeed have traveled from Mars to Earth in the hairline fractures of ALH84001 without being destroyed by heat. In particular, the fact that the nakhlites have never been heated above about 200 degrees Fahrenheit means that they were not heat-sterilized during ejection from Mars and transfer to Earth.

This work was sponsored by NASA and the National Science Foundation.

Original Source: MIT News Release

Artist’s concept of Mars Reconnaissance Orbiter. Image credit: NASA/JPL. Click to enlarge
NASA’s next mission to Mars will examine the red planet in unprecedented detail from low orbit and provide more data about the intriguing planet than all previous missions combined. The Mars Reconnaissance Orbiter and its launch vehicle are nearing final stages of preparation at NASA’s Kennedy Space Center, Fla., for a launch opportunity that begins Aug. 10.

The spacecraft will examine Martian features ranging from the top of the atmosphere to underground layering. Researchers will use it to study the history and distribution of Martian water. It will also support future Mars missions by characterizing landing sites and providing a high-data-rate communications relay.

“Mars Reconnaissance Orbiter is the next step in our ambitious exploration of Mars,” said NASA’s director, Mars Exploration Program, Science Mission Directorate, Douglas McCuistion. “We expect to use this spacecraft’s eyes in the sky in coming years as our primary tools to identify and evaluate the best places for future missions to land.”

The spacecraft carries six instruments for probing the atmosphere, surface and subsurface to characterize the planet and how it changed over time. One of the science payload’s three cameras will be the largest-diameter telescopic camera ever sent to another planet. It will reveal rocks and layers as small as the width of an office desk. Another camera will expand the present area of high-resolution coverage by a factor of 10. A third will provide global maps of Martian weather.

The other three instruments are a spectrometer for identifying water-related minerals in patches as small as a baseball infield; a ground-penetrating radar, supplied by the Italian Space Agency, to peer beneath the surface for layers or rock, ice and, if present, water; and a radiometer to monitor atmospheric dust, water vapor and temperature.

Two additional scientific investigations will analyze the motion of the spacecraft in orbit to study the structure of the upper atmosphere and the Martian gravity field.

“We will keep pursuing a follow-the-water strategy with Mars Reconnaissance Orbiter,” said Dr. Michael Meyer, Mars exploration chief scientist at NASA Headquarters. “Dramatic discoveries by Mars Global Surveyor, Mars Odyssey and the Mars Exploration Rovers about recent gullies, near-surface permafrost and ancient surface water have given us a new Mars in the past few years. Learning more about what has happened to the water will focus searches for possible Martian life, past or present.”

Dr. Richard Zurek of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., project scientist for the orbiter, said, “Higher resolution is a major driver for this mission. Every time we look with increased resolution, Mars has said, ‘Here’s something you didn’t expect. You don’t understand me yet.’ We’re sure to find surprises.”

The orbiter will reach Mars in March 2006. It will gradually adjust the shape of its orbit by aerobraking, a technique that uses the friction of careful dips into the planet’s upper atmosphere. For the mission’s 25-month primary science phase, beginning in November 2006, the planned orbit averages about 190 miles above the surface, more than 20 percent lower than the average for any of the three current Mars orbiters. The lower orbit adds to the ability to see Mars as it has never been seen before.

To get information from its instruments to Earth, the orbiter carries the biggest antenna ever sent to Mars and a transmitter powered by large solar panels. “It can send 10 times as much data per minute as any previous Mars spacecraft,” said JPL’s James Graf, project manager. “This increased return multiplies the value of the instruments by permitting increased coverage of the surface at higher resolution than ever before. The same telecommunications gear will be used to relay critical science data to Earth from landers.”

To loft so big a spacecraft, weighing more than two tons fully fueled, NASA will use a powerful Atlas V launch vehicle for the first time on an interplanetary mission.

The mission is managed by JPL, a division of the California Institute of Technology, Pasadena, for the NASA Science Mission Directorate. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft.

For information about Mars Reconnaissance Orbiter on the Web, visit http://www.nasa.gov/mro

Original Source: NASA News Release

The impact crater, known as “Endurance”. Image credit: NASA/JPL/Cornell. Click to enlarge
Mars is the planet that refuses to say “die.” In 1996, after centuries of speculation about canals, icecaps and vegetation, NASA’s David McKay reported seeing traces of ancient bacteria in a meteorite from Mars. Scientists have debated this finding ever since, and many now believe that the intriguing traces are probably not of biological origin.

Within the last few years, however, two simple chemicals intimately associated with life on Earth have been discovered on Mars. Large amounts of frozen water were discovered at the surface, and traces of methane appeared in the atmosphere.

Water is necessary for life as we know it, and most of the methane on Earth is made by microbes. Although the twin discoveries redoubled interest in the possibility of life on Mars, nobody is suggesting that anything is living on the planet’s surface, where temperatures average minus 63 degrees Celsius and harmful ultraviolet radiation pierces the thin atmosphere.

On Mars, as on Earth, temperatures rise as you go deeper down into the planet. Somewhere between a dozen and a thousand meters below the surface, conditions may be warm enough for liquid water, which is necessary for even non-biological methane production on Earth. But could a living ecosystem be hidden deep under the martian surface? On Earth, subterranean microbes survive without sunlight, free oxygen, or contact with the surface.

The question becomes more intriguing when you consider that most deep-Earth microbes are primitive, single-celled organisms that power their metabolism with chemical energy from their environment. These microbes are called “methanogens” because they make methane as a waste product.

Three NASA missions have discovered signs of water on Mars. In 2000, Mars Global Surveyor images of gullies suggested to many that water recently flowed on the martian surface. In May 2002, the gamma ray spectrometer on Mars Odyssey found a huge deposit of hydrogen in shallow polar soil — a sure sign of water ice. Then, in December 2004, researchers using the Mars Exploration Rover Opportunity announced that they had discovered rocks that had been formed by the periodic flooding of water on the surface. Such findings support the idea that Mars was warm and wet billions of years ago.

While water is a necessary condition for life, methane may be actual evidence of life. In the past two years, three separate research groups have seen spectral signs of methane on Mars:

* In 2003, Michael Mumma of Goddard Space Flight Center (GSFC) detected methane using spectrometers at two large earthbound telescopes. He has since told several scientific meetings that large variations exist in methane concentration on Mars. In a presentation at a NASA Astrobiology Institute meeting in April 2005, Mumma said the detection of martian methane varied with geography: there was an average of 200 parts per billion (ppb) detected at the equator, and 20 to 60 ppb near the poles.

* Vladimir Krasnopolsky, a research professor at Catholic University of America in Washington D.C., also detected methane on Mars. Like Mumma, Krasnopolsky used spectrometers on Earth-based telescopes. He calculated a global average of 11 ppb, with a range of 7 to 15 ppb. The data, as Krasnopolsky reported to a European Geosciences Union meeting in April 2004, came from 1999 observations of the whole planet’s disk.

“We didn’t try to make localized measurements because we did not expect any variation from place to place,” Krasnopolsky told Astrobiology Magazine.

* In December 2004, the European Space Agency’s Mars Express delivered the first methane data from a Mars orbiter. In the journal Science, Vittorio Formisano of the Institute of the Physics of Interplanetary Space in Rome and colleagues reported measurements made with the satellite’s Planetary Fourier Spectrometer. Their measurements were similar to Krasnopolsky’s numbers: A concentration of 10 ppb, plus or minus 5 ppb.

Although the Krasnopolsky and Formisano studies independently pointed to similar concentrations of methane, some planetary scientists express skepticism because the amount detected is very faint.

“The detections have been right at the detection limit of the instruments,” says William Boynton of the University of Arizona, principal investigator on the gamma ray spectrometer on Mars Odyssey. “I’m not completely convinced it’s a solid detection yet. It’s likely, but I wouldn’t put it in the bank.”

The matter of methane

The methane on Mars was detected with spectrometry — the analysis of light waves. Because each atom and molecule emits and absorbs characteristic wavelengths of light, spectrometers can determine the composition of distant objects by measuring these wavelengths. To study gases in the atmosphere of Mars, spectroscopists use instruments that can analyze the infrared light that is emitted when solar radiation warms the planet’s surface. As that infrared radiation speeds toward Earth, gases in the martian atmosphere can block, or absorb, certain frequencies. When the infrared light is concentrated in a telescope and separated by a spectroscope’s diffraction grating, the missing wavelengths show which particular atoms or molecules have absorbed light en route to Earth. Thus, a methane “line” on a spectroscope curve is a reflection of the light that methane has blocked.

There are complications, however. When faint light from a planet is collected in a terrestrial telescope, atoms and molecules in space or in Earth’s atmosphere will block some wavelengths. Spectroscopists must compensate for these non-martian signals. And because Mars is moving relative to Earth, the absorption lines appear in the “wrong” places until additional compensations are made.

Any methane on Mars today is not a legacy of ancient conditions, because solar radiation would destroy the molecules in the atmosphere within 600 years. Instead, the methane either was brought to Mars on comets or meteorites, or it was made on Mars. If we have glimpsed some made-on-Mars methane, was it made by geological or chemical processes — or by biology?

Original Source: NASA Astrobiology

Perspective view of Nicholson Crater central peak. Image credit: ESA. Click to enlarge
This image, taken by the High Resolution Stereo Camera (HRSC) on board ESA?s Mars Express spacecraft, shows Nicholson Crater, located at the southern edge of Amazonis Planitia on Mars.

The HRSC obtained this image during orbit 1104 with a ground resolution of approximately 15.3 metres per pixel. The scene shows the region around Nicholson Crater, at approximately 0.0? South and 195.5? East.

Nicholson Crater, measuring approximately 100 kilometres wide, is located at the southern edge of Amazonis Planitia, north-west of a region called Medusae Fossae.

Located in the centre of this crater is a raised feature, about 55 kilometres long and 37 kilometres wide, which extends to a maximum height of roughly 3.5 kilometres above the floor of the crater.

At present, it is still unclear how this central feature was shaped and what kind of processes led to its formation. It is thought that the remnant hill could be composed of material from underground or was built as a result of atmospheric deposition.

The tall feature in the centre of this hill is the central peak of the crater, which forms when the surface material ?rebounds? after being compressed during the formation of an impact crater.

However, it is clear that this feature has been heavily sculpted after its creation, by the action of wind or even water.

Original Source: ESA Mars Express

Dust devil tracks. Image credit: NASA/JPL. Click to enlarge
Ah, Martian summer! Finally, the days are long, just like on dear old Earth. And daytime highs rocket all the way up to a balmy 20?C (68?F) from the summer nighttime low of -90?C (-130?F), meaning you and your fellow astronauts can warm up your machinery earlier to get a good start on mining operations.

Dust devils on Mars form the same way they do in deserts on Earth. “You need strong surface heating, so the ground can get hotter than the air above it,” explains Lemmon. Heated less-dense air close to the ground rises, punching through the layer of cooler denser air above; rising plumes of hot air and falling plumes of cool air begin circulating vertically in convection cells. Now, if a horizontal gust of wind blows through, “it turns the convection cells on their sides, so they begin spinning horizontally, forming vertical columns–and starting a dust devil.”

Hot air rising through the center of the column powers the whirling air ever faster–fast enough to begin picking up sand. Sand scouring the ground then dislodges flour-fine dust, and the central column of hot rising air buoys that dust high aloft. Once prevailing horizontal winds begin pushing the dust devil across the ground, look out!

“If you were standing next to the Spirit rover right now [in Gusev Crater] in the middle of the day, you might see half a dozen dust devils,” says Lemmon. Each Martian spring or summer day, dust devils begin appearing about 10 AM as the ground heats, and start abating about 3 PM as the ground cools (Mars’s solar day of 24 hours 39 minutes is only 39 minutes longer than Earth?s). Although the exact frequency and duration of Martian dust devils is unknown, photographs from Mars Global Surveyor in orbit reveal innumerable wandering tracks at all latitudes on the planet. These tracks crisscross the surface where dust devils have scoured away loose surface material to reveal different-colored soil beneath.

Moreover, actual dust devils have been photographed from orbit–some of them as large as 1 to 2 kilometers across at their base and (from their shadows) clearly towering 8 to 10 km high.

What intrigues Farrell from having chased dust devils in the Arizona desert, however, is the strange fact that terrestrial dust devils are electrically charged–and Martian dust devils might be, too.

Dust devils get their charge from grains of sand and dust rubbing together in the whirlwind. When certain pairs of unlike materials rub together, one material gives up some of its electrons (negative charges) to the other material. Such separation of electric charges is called triboelectric charging, the prefix “tribo” (pronounced TRY-bo) meaning “rubbing.” Triboelectric charging makes your hair stand on end when you rub a balloon against your head. Dust and sand, like plastic and hair, form a tribolelectric pair. (Dust and sand aren’t necessarily made of the same stuff, notes Lemmon, because “dust can be blown in from anywhere.”) Smaller dust particles tend to charge negative, taking away electrons from the larger sand grains.

Because the rising central column of hot air that powers the dust devil carries the negatively-charged dust upward and leaves the heavier positively-charged sand swirling near the base, the charges get separated, creating an electric field. “On Earth, with instruments we’ve measured electric fields on the order of 20 thousand volts per meter (20 kV/m),” Farrell says. That’s peanuts compared to the electric fields in terrestrial thunderstorms, where lightning doesn’t flash until electric fields get 100 times greater–enough to ionize (break apart) air molecules.

But a mere 20 kV/m “is very close to the breakdown of the thin Martian atmosphere,” Farrell points out. More significantly, Martian dust devils are so much bigger than their terrestrial counterparts that their stored electrical energy may be much higher. “How would those fields discharge?” he asks. “Would you have Martian lightning inside the dust devils?” Even if lightning wouldn’t ordinarily occur naturally, the presence of an astronaut or rover or habitat might induce filamentary discharges, or local arcing. “The thing you’d really have to watch out for is corners, where electric fields can get very strong,” he adds. “You might want to make your vehicle or habitat rounded.”

Another consideration for astronauts on Mars would be “radio static as charged grains hit bare-wire antennas,” Farrell warns. And after the dust devil passed over and was gone, a lasting souvenir of its passage would be an increased adhesion of dust to spacesuits, vehicles, and habitats via electrostatic cling–the same phenomenon that causes socks to stick together when pulled out of a clothes dryer–making cleanup difficult before reentering a habitat.

Because Martian dust devils can tower 8 to 10 kilometers high, planetary meteorologists now think the devils may be responsible for throwing so much dust high into the Martian atmosphere. Importantly for astronauts, that dust may be carrying negative charges high into the atmosphere as well. Charge building up at the storm top could pose a hazard to a rocket taking off from Mars, as happened to Apollo 12 in November 1969 when it lifted off from Florida during a thunderstorm: the rocket exhaust ionized or broke down the air molecules, leaving a trail of charged molecules all the way down to the ground, triggering a lightning bolt that struck the spacecraft.

“Early sea navigators, like Columbus, understood that their ships had to be designed for extreme weather conditions,” Farrell points out. “To design a mission to Mars, we need to know the extremes of Martian weather–and those extremes appear to be in the form of dust storms and devils.”

Original Source: NASA News Release

Hubble Space Telescope view of Mars at its closest point 2 years ago. Image credit: Hubble. Click to enlarge.
There’s a rumor going around. You might have heard it at a 4th of July BBQ or family get-together. More likely you’ve read it on the Internet. It goes like this:

“The Red Planet is about to be spectacular.”

“Earth is catching up with Mars [for] the closest approach between the two planets in recorded history.”

“On August 27th ? Mars will look as large as the full moon.”

And finally, “NO ONE ALIVE TODAY WILL EVER SEE THIS AGAIN.”

Those are snippets from a widely-circulated email. Only the first sentence is true. The Red Planet is about to be spectacular. The rest is a hoax.

Here are the facts: Earth and Mars are converging for a close encounter this year on October 30th at 0319 Universal Time. Distance: 69 million kilometers. To the unaided eye, Mars will look like a bright red star, a pinprick of light, certainly not as wide as the full Moon.

Disappointed? Don’t be. If Mars did come close enough to rival the Moon, its gravity would alter Earth’s orbit and raise terrible tides.

Sixty-nine million km is good. At that distance, Mars shines brighter than anything else in the sky except the Sun, the Moon and Venus. The visual magnitude of Mars on Oct. 30, 2005, will be -2.3. Even inattentive sky watchers will notice it, rising at sundown and soaring overhead at midnight.

You might remember another encounter with Mars, about two years ago, on August 27, 2003. That was the closest in recorded history, by a whisker, and millions of people watched as the distance between Mars and Earth shrunk to 56 million km. This October’s encounter, at 69 million km, is similar. To casual observers, Mars will seem about as bright and beautiful in 2005 as it was in 2003.

Although closest approach is still months away, Mars is already conspicuous in the early morning. Before the sun comes up, it’s the brightest object in the eastern sky, really eye-catching. If you have a telescope, even a small one, point it at Mars. You can see the bright icy South Polar Cap and strange dark markings on the planet’s surface.

One day people will walk among those dark markings, exploring and prospecting, possibly mining ice from the polar caps to supply their settlements. It’s a key goal of NASA’s Vision for Space Exploration: to return to the Moon, to visit Mars and to go beyond.

Every day the view improves. Mars is coming–and that’s no hoax.

Original Source: NASA News Release

Panoramic view of Mars taken by NASA’s Spirit rover. Image credit: NASA/JPL. Click to enlarge.
Mars is a rocky planet with an ancient volcanic past, but new findings show the planet is more complex and active than previously believed – at least in certain places.

Finding those places, however, turns out to be trickier than just looking at landforms like river valleys or lakebeds or searching for specific minerals.

“Context is everything,” said Philip Christensen, Principal Investigator for the Thermal Emission Spectrometer (TES) on Mars Global Surveyor and for the Thermal Emission Imaging System (THEMIS) on Mars Odyssey, as well as lead scientist for the Mini-TES instruments on the Mars Exploration Rovers. “There has been a lot of excitement about finding specific features or minerals, but THEMIS, together with the TES infrared spectrometer, is giving us an overview by finding all the minerals. It gives us context – the underlying geology of the place.”

A paper led by Christensen, to be released online by the journal Nature on July 6, describes how a detailed examination of the Red Planet’s surface minerals using THEMIS and TES data yields surprising results in certain localized areas.

While the current rover missions have largely proved that in the distant past Mars may have had a lake or two, several different orbital mapping missions have found a basalt-rich planet that is the product of an ancient volcanic history. Geologically, it seems like a simple planet in the large scale – but then there are local windows showing far more complexity.

“From what we have seen to date, you might imagine going to Mars and seeing nothing but basalt,” said Christensen. “The evidence has always shown that the planet was active early, made some big volcanoes and then shut down and that was that. But when we looked more carefully we saw that there are these other places?When you look at the geology in the right spots, there is as much diversity in the rocks as you see on Earth.

“Once you get a glimpse of this complexity, you realize that there is a very complex world underneath that veneer of basalt.”

What Christensen and team found were localized deposits showing a distribution of igneous mineral types rivaling the range of minerals found on Earth – from primitive volcanic rocks like olivine-rich basalts to highly processed silica-rich rocks like granites.

The diversity of igneous minerals is important, Christensen explains, because it implies that the surface rocks have continued to be processed and reconstituted multiple times over an extended period of time.

“You melt the mantle and you get olivine basalts; you melt them again and you get basalt; you melt that and you make andesite; you melt that and you make dacite; you melt that and you make granite,” said Christensen. “Every time you re-melt a rock, the first thing to come off is the silica, so each time you melt it, you’re refining the silica.”

On Earth, such mineral evolution generally occurs as primitive volcanic rocks get folded back into the planet’s crust, re-melted and refined as faster melting components like silica separate out of the original material – a process known as mineral fractionation.

Mars, unlike Earth, does not have moving plates recycling the planet’s crust. However, Christensen’s results show that, like Earth, Mars has evolved and may still be evolving beneath the surface.

“Mars is a more complicated planet than we thought – the geology has kept chugging along and evolving over time,” Christensen said. “Though they’re not widespread, we’ve found dacite, and we’ve found granite. One way to make these granites is to make a whole volcano stacked up out of basalt – it gets tall enough and you begin to remelt the stuff deep down, and when you remelt the basalt, you can have granites forming.

“These are fairly small occurrences. On Earth, we have mountain ranges made of granite, on Mars we have so far only found a couple of globs. It’s not like the Earth in the extent of this geological evolution, but Mars is like the Earth in localized situations. It’s been hidden from us, but it’s a sophisticated, evolving planet after all,” he said.

Because the areas where the evolved igneous rocks occur are small, it has taken the high-resolution multispectral camera in Mars Odyssey’s THEMIS instrument (with a resolution of 100 meters) to find the minerals from orbit by finding a specific infrared signature in specific landforms. THEMIS’s mineral mapping has been 1500 times more detailed than TES’s, though the TES instrument’s infrared spectrometer (with a resolution of 3 kilometers) detects a much more detailed range of infrared emissions, making it more sensitive to different mineral compositions.

“We’re doing the thing that we set out to do: mapping the composition at mesoscales,” Christensen noted. “THEMIS identifies the area, then we go back and find what may be just a single, over-looked TES pixel and analyze it. The two were really planned to work together and that’s exactly what we’ve been doing. We use these two instruments in a synergistic way and together they’re perfect.”

Though Mars mapping has been going on for many years, Christensen notes that some of the most interesting places on the planet have yet to be identified and explored.

“If you drained the Earth’s oceans and looked at it from space, you would probably reach the same conclusion – a quiet, basaltic planet,” he said. “But then, if you searched carefully, you might find Yellowstone and realize that there was a lot going on below the surface of the planet that you weren’t aware of. We’re at that stage now in looking at Mars.”

Original Source: NASA Astrobiology

Graduate student Alison Skelley in the Atacama desert in Chile. Image credit: Richard Mathies lab/UC Berkeley. Click to enlarge.
The dry, dusty, treeless expanse of Chile’s Atacama Desert is the most lifeless spot on the face of the Earth, and that’s why Alison Skelley and Richard Mathies joined a team of NASA scientists there earlier this month.

The University of California, Berkeley, scientists knew that if the Mars Organic Analyzer (MOA) they’d built could detect life in that crusty, arid land, then it would have a good chance some day of detecting life on the planet Mars.
Collecting samples in the Atacama Desert

In a place that hadn’t seen a blade of grass or a bug for ages, and contending with dust and temperature extremes that left her either freezing or sweating, Skelley ran 340 tests that proved the instrument could unambiguously detect amino acids, the building blocks of proteins. More importantly, she and Mathies were able to detect the preference of Earth’s amino acids for left-handedness over right-handedness. This “homochirality” is a hallmark of life that Mathies thinks is a critical test that must be done on Mars.

“We feel that measuring homochirality – a prevalence of one type of handedness over another – would be absolute proof of life,” said Mathies, professor of chemistry at UC Berkeley and Skelley’s research advisor. “We’ve shown on Earth, in the most Mars-like environment available, that this instrument is a thousand times better at detecting biomarkers than any instrument put on Mars before.”

The instrument has been chosen to fly aboard the European Space Agency’s ExoMars mission, now scheduled to launch in 2011. The MOA will be integrated with the Mars Organic Detector, which is being assembled by scientists directed by Frank Grunthaner at the Jet Propulsion Laboratory (JPL) in Pasadena together with Jeff Bada’s group at UC San Diego’s Scripps Institution of Oceanography.

Skelley, a graduate student who has been working on amino acid detection with Mathies for five years and on the portable MOA analyzer for the past two years, is hoping to remain with the project as it goes through miniaturization and improvements at JPL over the next seven years in preparation for its long-range mission. In fact, she and Mathies hope she’s the one looking at MOA data when it’s finally radioed back from the Red Planet.

“When I first started this project, I had seen photos of the Martian surface and possible signs of water, but the existence of liquid water was speculative, and people thought I was crazy to be working on an experiment to detect life on Mars,” Skelley said. “I feel vindicated now, thanks to the work of NASA and others that shows there used to be running liquid water on the surface of Mars.”

“The connection between water and life has been made very strongly, and we think there is a good chance there is or was some life form on Mars,” Mathies said. “Thanks to Alison’s work, we’re now in the right position at the right time to do the right experiment to find life on Mars.”

Mathies said that his experiment is the only one proposed for ExoMars or the United States’ own Mars mission – NASA’s roving, robotic Mars Science Laboratory mission – that could unambiguously find signs of life. The experiment uses state-of-the-art capillary electrophoresis arrays, novel micro-valve systems and portable instrument designs pioneered in Mathies’ lab to look for homochirality in amino acids. These microarrays with microfluidic channels are 100 to 1,000 times more sensitive for amino acid detection than the original life detection instrument flown on the Viking Landers in the 1970s.

The Atacama Desert was selected by NASA scientists as one of the key spots to test instruments destined for Mars, primarily because of its oxidizing, acidic soil, which is similar to the rusty red oxidized iron surface of Mars. Skelley and colleagues Pascale Ehrenfreund, professor of astrochemistry at Leiden University in The Netherlands, and JPL scientist Frank Grunthaner visited the desert last year, but were not able to test the complete, integrated analyzer.

This year, Skelley, Mathies and other team members carried the complete analyzers in three large cases to Chile by plane – in itself a test of the ruggedness of the equipment – and trucked them to the barren Yunguy field station, essentially a ramshackle building at a deserted crossroads. With a noisy Honda generator providing power, they set up their experiments and, with six other colleagues, tested the integrated subcritical water extractor together with the MOA on samples from popular test sites such as the “Rock Garden” and the “Soil Pit.”

One thing they learned is that with low environmental levels of organic compounds, as is likely to be the case on Mars, the microfluidic channels in the capillary disks don’t get clogged as readily as they do when used to test samples in Berkeley with its high bioorganic levels. That means they’ll need fewer channels on the instrument that travels to Mars, and the scanner used to read out the data needn’t be as elaborate. This translates into a cheaper and easier way to build instruments, but more importantly, an instrument that is smaller and uses less power.

With the success of this crucial field test, Skelley and Mathies are eager to get to work on a prototype of their instrument that would fit in the allowed space within the ExoMars spacecraft.

“I’m much more optimistic that we could detect life on Mars, if it’s there,” Mathies said.

Original Source: UC Berkeley News Release

Artist illustration of Mars Express with all three booms deployed. Image credit: ESA. Click to enlarge.
MARSIS, the Mars Advanced Radar for Subsurface and Ionosphere Sounding on board ESA?s Mars Express orbiter, is now fully deployed, has undergone its first check-out and is ready to start operations around the Red Planet.

With this radar, the Mars Express orbiter at last has its full complement of instruments available to probe the planet?s atmosphere, surface and subsurface structure.

MARSIS consists of three antennas: two ?dipole? booms 20 metres long, and one 7-metre ?monopole? boom oriented perpendicular to the first two. Its importance is that it is the first- ever means of looking at what may lie below the surface of Mars.

The delicate three-stage phase of radar boom deployment, and all the following tests to verify spacecraft integrity, took place between 2 May and 19 June. Deployment of the first boom was completed on 10 May. That boom, initially stuck in unlocked mode, was later released by exploiting solar heating of its hinges.

Taking advantage of the lessons learnt from that first boom-deployment, the second 20-metre boom was successfully deployed on 14 June. Subsequently, ESA?s ground team at the European Space Operations Centre (ESOC) in Darmstadt, Germany, commanded the non-critical deployment of the third boom on 17 June, which proceeded smoothly as planned.

MARSIS?s ability to transmit radio waves in space was tried out for the first time on 19 June, when the instrument was switched on and performed a successful transmission test.

The instrument works by sending a coded stream of radio waves towards Mars at night, and analysing their distinctive echoes. From this, scientists can then make deductions about the surface and subsurface structure. The key search is for water. But MARSIS’s capabilities do not stop there. The same methods can also be used by day to probe the structure of the upper atmosphere.

Before starting its scientific observations, MARSIS has to undergo its commissioning phase. This is a routine procedure for any spacecraft instrument, necessary to test its performance in orbit using real targets in situ. In this case, the commissioning will last about ten days, or 38 spacecraft orbital passes, starting on 23 June and ending on 4 July.

During the commissioning phase, MARSIS will be pointed straight down (nadir pointing mode) to look at Mars from those parts of the elliptical orbit where the spacecraft is closest to the surface (around the pericentre). During this phase, it will cover the areas of Mars between 15? S and 70? N latitude. This includes interesting features such as the northern plains and the Tharsis region, so there is a small chance of exciting discoveries being made early on.

On 4 July, when the commissioning operations end, MARSIS will start its nominal science observations. In the initial phase, it will operate in survey mode. It will make observations of the Martian globe?s night-side. This is favourable to deep subsurface sounding, because during the night the ionosphere of Mars does not interfere with the lower-frequency signals needed by the instrument to penetrate the planet’s surface, down to a depth of 5 kilometres.

Through to mid-July, the radar will look at all Martian longitudes between 30? S and 60? N latitude, in nadir pointing mode. This area, which includes the smooth northern plains, may have once contained large amounts of water.

The MARSIS operation altitudes are up to 800 kilometres for subsurface sounding and up to 1200 kilometres for studying the ionosphere. From mid-July, the orbit’s closest approach point will enter the day-side of Mars and stay there until December. In this phase, using higher frequency radio waves, the instrument will continue shallow probing of the subsurface and start atmospheric sounding.

?Overcoming all the technical challenges to operate an instrument like MARSIS, which had never flown in space before this mission, has been made possible thanks to magnificent cooperation between experts on both sides of the Atlantic,? said Professor David Southwood, ESA’s Science Programme Director. ?The effort is indeed worthwhile as, with MARSIS now at work, whatever we find, we are moving into new territory; ESA?s Mars Express is now well and truly one of the most important scientific missions to Mars to date,? he concluded.

Original Source: ESA News Release