We Need To Tackle Mars Dust Before Launching Manned Mission

Manned missions to Mars could be scuppered by the tiniest of annoyances — dust. A team of space safety experts repeatedly flagged up the issue at the Humans 2 Mars Summit (H2M) in Washington DC, according to a report by the New Scientist.

The conference is a highly reputable one, attended by the likes of Nasa chief Charles Bolden. Its focus is on debating the main obstacles we need to overcome in order to send humans to Mars by 2030. Now, with more than 20,000 people applying (and paying) for the chance to go to the Red Planet for Mars One’s reality TV show, the possibility of toxic dust is probably going to be one giant addition to any disclaimer the hopeful astronauts have to sign.

Dust, as we all know, gets everywhere. If you’ve ever been in a Khamsin — the hot, dry, dusty seasonal winds that blow in the Middle East — you’ll know it’s fairly unpleasant. It gets in your eyes, your clothes and your throat grows hoarse from swallowing it. Earthly dust we can deal with, but it turns out dust on the Red Planet has the potential to do far more than irritate.

Nasa chief medical officer Richard Williams, Paragon Space Development cofounder Grant Anderson, Curiosity Rover’s Sample Analysis at Mars (SAM) principle investigator Paul Mahaffy and Boeing engineer and technical lead for the Environmental Control and Life Support System on the ISS Greg Gentry painted a picture of an inhospitable Mars where the dust is potentially inescapable. They pointed to serveral examples from Mars itself, and from Moon missions, that support this assumption.

Most recently Curiosity scooped up a robotic handful of Mars dust from Rocksnest that Mahaffy believes contains perchlorates. It’s something that was previously picked up by Nasa’a Phoenix lander on Mars in 2008 near the planet’s north pole. Perchlorates are salts that in large quantities can interrupt iodine uptake in the thyroid gland, and thus potentially interfere with the normal release of hormones.

Curiosity’s Chemcam also took samples from veins in the YellowKnife region and found high levels of calcium sulfate that it is predicted exist in the form of bassanite or gypsum. We have gypsum here on Earth, where it’s commonly used in plaster or fertilisers, but we don’t know how much there is on Mars’ surface.

“Gypsum is not really toxic per se, but if you breathe it in you do start to see a build-up in the lungs that’s equivalent to the coal-dust lung experienced by miners,” said Anderson. “That leads to breakdowns in lung capacity.”

Of course astronauts heading to Mars on a one-way trip will be in space suits any time they’re wandering round the planet’s surface, but our trips to the Moon show how impossible it is to keep dust off those suits. Reports from Apollo missions in the late 60s and early 70s revealed what a pain the dust was for explorers. It was so sharp it would wear through their outer gloves and would stick to everything, and it reportedly even caused “lunar hayfever”.

Part of it was down to the dust’s spiky surface, but a large part was also down to how static it was. UV rays and solar winds manipulate electron levels by day and night, powering up dust’s electrostatic charge. Wetting surfaces to wipe it off only made the dust stick more firmly. It’s like the silicate minerals all over Mars’ surface — if they mix with water in human lungs, they will become more damaging, combining to create dangerous chemicals.

Anderson predicts Mars dust will also be charged up, and that it will be nearly impossible to stop them entering a safe site through the airlocks where astronauts acclimatise back to normal conditions.

“The Apollo programme spent $17 million (£11 million) trying to solve their lunar dust problems, and I’m not sure they made much progress, because they had to do the tests on Earth,” said Anderson. “For Mars, the precursor robotic missions should all have some way to test how dust is going to kill you.”

According to a blog in the Washington Post Gentry commented that astronauts aboard the ISS spend most of their time making sure instruments, filters and surfaces are clean — “we are happy when we get 30 hours of science out of the crew a week,” he said.

So for now, it looks like Dyson needs to get to work on a spaceworthy air purifier.

Watery Science ‘Jackpot’ Discovered by Curiosity

Image: Curiosity found widespread evidence for flowing water in the highly diverse, rocky scenery shown in this photo mosaic from the edge of Yellowknife Bay on Sol 157 (Jan 14, 2013). The rover will soon conduct 1st Martian rock drilling operation at flat, light toned rocks at the outcrop called “John Klein”, at center. ‘John Klein’ drill site and ‘Sheep Bed’ outcrop ledges to right of rover arm are filled with numerous mineral veins and spherical concretions which strongly suggest precipitation of minerals from liquid water. ‘Snake River’ rock formation is the linear chain of rocks protruding up from the Martian sand near rover wheel. Credit: NASA/JPL-Caltech/Ken Kremer/Marco Di Lorenzo

The Curiosity rover hit the science “jackpot” and has discovered widespread further evidence of multiple episodes of liquid water flowing over ancient Mars billions of years ago when the planet was warmer and wetter, scientists announced. The watery evidence comes in the form of water bearing mineral veins, cross-bedded layering, nodules and spherical sedimentary concretions.

Any day now the robot will be instructed to drill directly into veined rocks where water once flowed, the team announced at a media briefing this week.

Delighted researchers said Curiosity surprisingly found lots of evidence for light-toned chains of linear mineral veins inside fractured rocks littering the highly diverse Martian terrain – using her array of ten state-of-the-art science instruments. Veins form when liquid water circulates through fractures and deposit minerals, gradually filling the insides of the fractured rocks over time.

Sometime in the next two weeks or so, NASA’s car sized rover will carry out history’s first ever drilling inside a Martian rock that was “percolated” by liquid water – an essential prerequisite for life as we know. A powdered sample will then be delivered to the robots duo of analytical chemistry labs (CheMin & SAM) to determine its elemental composition and ascertain whether organic molecules are present.

The drill target area is named “John Klein” outcrop, in tribute to a team member who was the deputy project manager for Curiosity at JPL for several years and who passed away in 2011.

“We identified a potential drill target and are preparing to do drill activities in the next two weeks. We are ready to go,” said Richard Cook, the project manager of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif.

“Drilling [into a rock] is the most significant engineering activity since landing. It is the most difficult aspect of the surface mission, interacting with an unknown surface terrain, and has never been done on Mars. We will go slowly. It will take some time to deliver samples to CheMin and SAM and will be a great set of scientific measurements.”

Image caption: Mineral veins of calcium sulfate discovered by Curiosity at ‘Sheepbed’ Outcrop. These veins form when water circulates through fractures, depositing minerals along the sides of the fracture, to form a vein. These vein fills are characteristic of the stratigraphically lowest unit in the “Yellowknife Bay” area where Curiosity is currently exploring and were imaged on Sol 126 (Dec. 13, 2012) by the telephoto Mastcam camera. Image has been white-balanced. Credit: NASA/JPL-Caltech/MSSS

“The scientists have been let into the candy store,” said Cook referring to the unexpected wealth of science targets surrounding the rover at this moment.

Curiosity is just a few meters away from ‘John Klein’ and will drive to the site shortly from her location inside ‘Yellowknife Bay’ beside the ‘Snake River’ rock formation. To see where Curiosity is in context with ‘John Klein’ and “Snake River’, see our annotated context mosaic (by Ken Kremer & Marco Di Lorenzo) as the rover collects data at a rock ledge.

The white colored veins were discovered over the past few weeks- using the high resolution mast- mounted imaging cameras and ChemCam laser firing spectrometer -at exactly the vicinity where Curiosity is currently investigating ; around a shallow basin called Yellowknife Bay and roughly a half mile away from the landing site inside Gale Crater.

“This lowest unit that we are at in Yellowknife Bay, the very farthest thing we drove to, turns out to be kind of the ‘jackpot’ unit here,” said John Grotzinger, the mission’s chief scientist of the California Institute of Technology. “It is literally shot through with these fractures and vein fills.”

Image caption: ‘John Klein’ Site Selected for Curiosity’s Drill Debut. This view shows the patch of veined, flat-lying rock selected as the first drilling site. The rover’s right Mast Camera equipped with a telephoto lens, was about 16 feet (5 meters) away from the site when it recorded this mosaic on sol 153 (Jan. 10, 2013). The area is shot full of fractures and veins, with the intervening rock also containing concretions, which are small spherical concentrations of minerals. Enlargement A shows a high concentration of ridge-like veins protruding above the surface. Some of the veins have two walls and an eroded interior. Enlargement B shows that in some portions of this feature, there is a horizontal discontinuity a few centimeters or inches beneath the surface. The discontinuity may be a bed, a fracture, or potentially a horizontal vein. Enlargement C shows a hole developed in the sand that overlies a fracture, implying infiltration of sand down into the fracture system. Image has been white-balanced. Credit: NASA/JPL-Caltech/MSSS

Shortly after landing the team took a calculated gamble and decided to take a several months long detour away from the main destination of the towering, sedimentary mountain named Mount Sharp, and instead drive to an area dubbed ‘Glenelg’ and home to ‘Yellowknife Bay’, because it sits at the junction of a trio of different geologic terrains. Glenelg exhibits high thermal inertia and helps put the entire region in better scientific context. The gamble has clearly payed off.

“We chose to go there because we saw something anomalous, but wouldn’t have predicted any of this from orbit,” said Grotzinger.

The Chemistry and Camera (ChemCam) instrument found elevated levels of calcium, sulfur and hydrogen. Hydrogen is indicative of water.

The mineral veins are probably comprised of calcium sulfate – which exists in several hydrated (water bearing) forms.

“The ChemCam spectra point to a composition very high in calcium. These veins are likely composed of hydrated calcium sulfate, such as bassinite or gypsum, depending on the hydration state,” said ChemCam team member Nicolas Mangold of the Laboratoire de Planétologie et Géodynamique de Nantes in France. “On Earth, forming veins like these requires water circulating in fractures and occur at low to moderate temperatures.”

The newly found veins appear quite similar to analogous veins discovered in late 2011 by NASA’s Opportunity rover – Curiosity’s older sister – inside Endeavour crater and nearly on the opposite side of Mars. See our Opportunity vein mosaic featured at APOD on Dec. 11, 2011 to learn more about veined rocks.

“What these vein fills tell us is water moved and percolated through these rocks, through these fracture networks and then minerals precipitated to form the white material which ChemCam has concluded is very likely a calcium sulfate, probably hydrated in origin,” Grotzinger explained.

“So this is the first time in this mission that we have seen something that is not just an aqueous environment, but one that also results in precipitation of minerals, which is very attractive to us.”

Yellowknife Bay and the ‘John Klein’ drilling area outcrop are chock full of mineral veins and sedimentary concretions.

“When you put all this together it says that basically these rocks were saturated with water. There may be several phases to this history of water, but that’s still to be worked out.”

“This has been really exciting and we can’t wait to start drilling,” Grotzinger emphasized.

Curiosity can drill about 2 inches (5 cm) into rocks. Ultimately a powdered sample about half an aspirin tablet in size will be delivered to SAM and CheMin after a few weeks. All rover systems and instruments are healthy, said Cook.

Grotzinger said that Curiosity will be instructed to drive over the veins to try and break them up and expose fresh surfaces for analysis. Then she will drill directly into a vein and hopefully catch some of the surrounding material as well.

“This will reveal the mineralogy of the vein filling material and how many hydrated mineral phases are present. The main goal is this will give us an assessment of the habitability of this environment.”

As the rover has driven down the shallow depression to deeper stratigraphic layers, the units are older in time. After the first drill sample is fully analyzed, Grotzinger told me that the team will reevaluate whether to drill into a second rock.

The team doesn’t yet know whether the flowing water from which the veins precipitated was a more neutral pH or more acidic. “It’s too early to tell. We need to drill into the rock to tell and determine the mineralogy,” Grotzinger told me. Neutral water is more hospitable to life.

How long the episodes of water flowed is not yet known and it’s a complex history. But the water was at least hip to ankle deep at times and able to transport and round the gravel.

Image caption: Curiosity’s Traverse into Different Terrain. This image maps the traverse of NASA’s Mars rover Curiosity from “Bradbury Landing” to “Yellowknife Bay,” with an inset documenting a change in the ground’s thermal properties with arrival at a different type of terrain. Credit: NASA/JPL-Caltech/Univ. of Arizona/CAB(CSIC-INTA)/FMI

Drilling goes to the heart of the mission and will mark a historic feat in planetary exploration – as the first time that an indigenous sample has been cored from the interior of a rock on another planet and subsequently analyzed by chemical spectrometers to determine its elemental composition and determine if organic molecules are present .

The high powered hammering drill is located on the tool turret at the end of the car-sized robots 7 foot (2.1 meter) long mechanical arm . It is the last of Curiosity’s ten instruments that remains to be checked out and put into action.

Curiosity landed on the Red Planet five months ago inside Gale Crater to investigate whether Mars ever offered an environment favorable for microbial life, past or present and is now nearly a quarter of the way through her two year prime mission.

Curiosity might reach the base of Mount Sharp by the end of 2013, which is about 6 miles (10 km) away as the Martian crow flies.

Image Caption: Calcium-Rich Veins in Martian Rocks. This graphic shows close-ups of light-toned veins in rocks in the “Yellowknife Bay” area of Mars together with analyses of their composition. The top part of the image shows a close-up of the rock named “Crest,” taken by the remote micro-imager (RMI) on Curiosity’s Chemistry and Camera (ChemCam) instrument above the analysis of the elements detected by using ChemCam’s laser to zap the target. The spectral profile of Crest’s light-colored vein is shown in red, while that of a basaltic calibration target of known composition is shown in black. The bottom part of the image shows ChemCam’s close-up of the rock named “Rapitan” with the analysis of its elemental composition. The spectral profile of Rapitan’s light-colored vein is shown in blue, while that of a basaltic calibration target of known composition is shown in black. These results suggest the veins are unlike typical basaltic material. They are depleted in silica and composed of a calcium-bearing mineral.
Credit: NASA/JPL-Caltech/LANL/CNES/IRAP/LPGNantes/CNRS

I Am SAM

Image 1: Portrait of Curiosity assembled from raw images acquired with MAHLI on Sol 85 (Nov. 11. 2012 UTC) Credit: NASA/JPL-Caltech/Malin Space Science Systems. Composite by Jason Major.
Image 2: Annotated photo of SAM with side covers removed

Yesterday Mars Science Laboratory principal investigator John Grotzinger set the entire space science world abuzz with a tantalizing promise of “earthshaking” news on the horizon — literally “one for the history books,” as he put it in an interview with NPR. It seems one of Curiosity’s main science tools, the Sample Analysis at Mars (SAM) instrument, has discovered… something… within recently-gathered samples, possibly in windblown-material scooped at a site called “Rocknest” earlier this month.

For now, though, the MSL team is keeping quiet on any more details until they’re reasonably sure they know what they have. Speculations abound — some serious, some not — but the bottom line is we’ll all have to wait for the official news to be released. In the meantime, here’s your chance to learn a little more about a fascinating high-tech Mars-tasting gadget called SAM.

About the size of a window air conditioning unit, the Sample Analysis at Mars (SAM) instrument is contained within the front section of NASA’s Curiosity rover. Actually a suite of three instruments, SAM consists of a Gas Chromatograph (GC), a Quadrupole Mass Spectrometer (QMS), and a Tunable Laser Spectrometer (TLS), as well as systems that manipulate and process samples.

Although mostly contained entirely within Curiosity, SAM does have two small inlet tubes that allow access for soil samples gathered with the rover’s arm, as well as inlets for atmospheric gases.

On Earth all of these different instruments would fill a lab. But to fit them all inside the Curiosity, which is about the size of a Mini Cooper (but only half the mass), they were painstakingly reduced in size to fit within a single rectangular structure about 40 kg (88 lbs).

Here’s how SAM’s components work:

The Gas Chromatograph (GC)
The GC has six complementary chromatographic columns. The GC assembly sorts, measures, and identifies gases it separates from mixtures of gases by pushing the mixed gases through long, coiled tubes with a stream of helium gas. It sorts the gas molecules by weight: they emerge from the tube in order from lightest (out first) to heaviest (out last). Once the gases are sorted, the GC can direct quantities of the separated gases into the QMS or TLS for further analysis.

The Quadrupole Mass Spectrometer (QMS)
The QMS identifies gases by the molecular weight and electrical charge of their ionized states. It fires high-speed electrons at the molecules, breaking them into fragments. It then sorts the fragments by weight with AC and DC electric fields. The spectra generated by the QMS detector uniquely identify the molecules in the gases.

The Tunable Laser Spectrometer (TLS)
The TLS uses absorption of light at specific wavelengths to measure concentrations and isotope ratios of specific chemicals important to life: methane, carbon dioxide, and water vapor. Isotopes are variants of the same element with different atomic weights, and their ratios can provide information about Mars’ geologic — and possibly biologic — history.

The QMS and the GC can operate together in a GCMS mode for separation and definitive identification of organic compounds. The TLS obtains precise isotope ratios for C and O in carbon dioxide and measures trace levels of methane and its carbon isotope.

In addition to these three analytical instruments SAM also has mechanical support devices: a sample manipulation system (SMS) and a Chemical Separation and Processing Laboratory (CSPL). The CSPL includes high conductance and micro valves, gas manifolds with heaters and temperature monitors, chemical and mechanical pumps, carrier gas reservoirs and regulators, pressure monitors, pyrolysis ovens, and chemical scrubbers and getters.

The SMS has a wheel of 74 small cups where soil samples gathered by Curiosity’s robotic arm are prepared for analysis. 59 are quartz cups that are small ovens which can be heated to very high temperatures to pull gases from the powdered samples. 9 sealed cups are filled with chemical solvents for lower-temperature experiments designed to search for organic compounds. The other 9 cups contain calibration materials.

With this suite of precision tools SAM is specifically designed to search for evidence of a habitable environment on Mars, whether past or present. As it takes up over half of the rover’s scientific payload area, you could say that Curiosity itself is specifically designed to carry SAM around Mars (although we won’t tell that to the other instruments!)

Knowing only that the “exciting” news from Grotzinger and his team is coming from data gathered by SAM, one could safely assume that it has something to do with a discovery of organic chemistry of some sort… but we’ll all have to wait a few more weeks to know for sure. Still, as that is the primary objective of MSL and Curiosity is barely over 100 Martian days into its mission, even the smallest hint of big news has everyone’s attention.

Like any big institution, NASA would love to trumpet a major finding, especially at a time when budget decisions are being made.
– Joe Palca, NPR article

“This data is gonna be one for the history books,” said Grotzinger. “It’s looking really good.” (Read more here.)

Find out more about SAM and Curiosity’s other instruments here, and check out a quick video overview of SAM here.

The result of an international effort between scientists and engineers, SAM was built and tested at NASA Goddard Space Flight Center in Greenbelt, Maryland. Paul Mahaffy is SAM’s Principal Investigator.

Additional source: NASA Goddard Space Flight Center SAM site. Inset images: SAM assembly/SAM solid sample inlets. Image credits: NASA/JPL-Caltech.

Curiosity Rover’s Secret Historic Breakthrough? Speculation Centers on Organic Molecules

Much of the internet is buzzing over upcoming “big news” from NASA’s Curiosity rover, but the space agency’s scientists are keeping quiet about the details.

The report comes by way of the rover’s principal investigator, geologist John Grotzinger of Caltech, who said that Curiosity has uncovered exciting new results from a sample of Martian soil recently scooped up and placed in the Sample Analysis at Mars (SAM) instrument.

“This data is gonna be one for the history books. It’s looking really good,” Grotzinger told NPR in an segment published Nov. 20. Curiosity’s SAM instrument contains a vast array of tools that can vaporize soil and rocks to analyze them and measure the abundances of certain light elements such as carbon, oxygen, and nitrogen – chemicals typically associated with life.

The mystery will be revealed shortly, though. Grotzinger told Wired through e-mail that NASA would hold a press conference about the results during the 2012 American Geophysical Union meeting in San Francisco from Dec. 3 to 7. Because it’s so potentially earth-shaking, Grotzinger said the team remains cautious and is checking and double-checking their results. But while NASA is refusing to discuss the findings with anyone outside the team, especially reporters, other scientists are free to speculate.

“If it’s going in the history books, organic material is what I expect,” says planetary scientist Peter Smith from the University of Arizona’s Lunar and Planetary Laboratory. Smith is formerly the principal investigator on a previous Mars mission, the Phoenix lander, which touched down at the Martian North Pole in 2008. “It may be just a hint, but even a hint would be exciting.”

Smith added that he is not in contact with anyone from the Curiosity team about their results and offered his assessment as an informed outside researcher.

Organic molecules are those that contain carbon and are potential indicators of life. During its mission, Phoenix heated a sample of soil to search for organics but these efforts were stymied by the presence of perchlorates, chemical salts that sit in the Martian soil. Perchlorates react to heat and destroy any complex organic molecules, leaving only carbon dioxide, which is abundant in the Martian atmosphere.

The Viking landers, which explored opposite sides of Mars in the late 1970s, also conducted a search for organic molecules and came up empty. For decades afterward, astronomers considered Mars to be a dead planet, with conditions not very conducive to life. After the results from Phoenix, scientists realized that perchlorates were probably messing with those earlier findings as well, and could account for their negative outcome.

Curiosity’s suite of laboratory instruments are able to slowly heat a sample in a way that doesn’t trigger the perchlorates. They can also weigh any molecules present, determining how much carbon, oxygen, and hydrogen they are made from. Simple organic compounds wouldn’t be completely shocking, said Smith, since these probably come from meteorites originating in the asteroid belt and probably are around on present-day Mars. But they would indicate that the building blocks for life are present on Mars and might only need the addition of water, which Mars had in the past, in order to produce organisms.

“If they found signatures of a very complex organic type, that would be astounding,” said Smith, since they would likely be leftovers from complex life forms that once roamed Mars. But the odds of finding such a startling result in a sample of sand scooped from a random dune are “very, very low,” Smith said.

Smith cautioned against speculating too much, since rumors have a way of spreading rapidly when it comes to any discussion of potential life on Mars. During his tenure on the Phoenix mission, his team was evaluating the interesting perchlorate results, which they kept secret during analysis. Rumors got out and then became worse when some unsubstantiated report claimed a member of his team meeting was meeting with the White House.

“When you keep things secret, people start thinking all kinds of crazy things,” he said.

(via scinerds)

Mars Mystery: Has Curiosity Rover Made Big Discovery?

Image: NASA’s Mars rover Curiosity used its Mars Hand Lens Imager (MAHLI) to snap a set of 55 high-resolution images on Oct. 31, 2012. Researchers stitched the pictures together to create this full-color self-portrait.
CREDIT: NASA/JPL-Caltech/Malin Space Science Systems

This story was updated at 2:25 p.m. Eastern time.
NASA’s Mars rover Curiosity has apparently made a discovery “for the history books,” but we’ll have to wait a few weeks to learn what the new Red Planet find may be, media reports suggest.

The discovery was made by Curiosity’s Sample Analysis at Mars instrument, NPR reported today (Nov. 20). SAM is the rover’s onboard chemistry lab, and it’s capable of identifying organic compounds — the carbon-containing building blocks of life as we know it.

SAM apparently spotted something interesting in a soil sample Curiosity’s huge robotic arm delivered to the instrument recently.

“This data is gonna be one for the history books,” Curiosity chief scientist John Grotzinger, of Caltech in Pasadena, told NPR. “It’s looking really good.”

The rover team won’t be ready to announce just what SAM found for several weeks, NPR reported, as scientists want to check and double-check the results. Indeed, Grotzinger confirmed to SPACE.com that the news will come out at the fall meeting of the American Geophysical Union, which takes place Dec. 3-7 in San Francisco.

The $2.5 billion Curiosity rover landed inside Mars’ huge Gale Crater on Aug. 5, kicking off a two-year mission to determine if Mars has ever been capable of supporting microbial life.

The car-size robot carries 10 different instruments to aid in its quest, but SAM is the rover’s heart, taking up more than half of its science payload by weight.

In addition to analyzing soil samples, SAM also takes the measure of Red Planet air. Many scientists are keen to see if Curiosity detects any methane, which is produced by many lifeforms here on Earth. A SAM analysis of Curiosity’s first few sniffs found no definitive trace of the gas in the Martian atmosphere, but the rover will keep looking.

Curiosity began driving again Friday (Nov. 16) after spending six weeks testing its soil-scooping gear at a site called “Rocknest.” The rover will soon try out its rock-boring drill for the first time on the Red Planet, scientists have said.

marswiggles:

Navcam, Sol 96 — At left, the SAM (Soil Analysis at Mars) tool, which recently ingested Mars soil.

Curiosity Rover Update: Sniffing Mars’ Atmosphere

What has Curiosity been up to lately? The rover’s Sample Analysis at Mars (SAM) instruments makes up more than half the science payload on board MSL, and it is now searching for compounds of the element carbon — including the enticing methane that has been observed in Mars’ atmosphere from telescopes and instruments on Earth. These are the elements that are associated with life, and SAM is trying to determine if methane can be detected from the surface, as well. So far, the rover has not found “definitive evidence” beyond data uncertainty of methane in Mars’ thin atmosphere. But that doesn’t close the door on the subject. It is still early in the mission, and the methane on Mars has been cyclical in nature.

“A search for methane was made on multiple nighttime runs, but so far we have no definitive detection of methane,” said Chris Webster, the team lead for MSL’s Tunable Laser Spectrometer. The instrument has detected values of no methane at all up to 5 parts per billion, but the “data uncertainty is larger than this,” Webster said. “We do plan on additional runs, of course, to look for variability.”

But, of course, methane has been detected in certain areas, not necessarily planet-wide.

“In the Gale Crater, at the moment, we don’t have a definite detection of methane,” said Sushil Atreya, a co-investigator with the SAM instruments. “On the other hand, the source doesn’t have to be at Gale Crater. If there is a source of methane elsewhere, it does not take very long for it to get distributed all over the planet. It takes on the order of about three months. That is all we can say at this point.”

Methane is enticing because it could indicate life or some sort, perhaps microbial life. But methane can also be produced by certain geologic processes, and recently, a team of researchers suggested that methane could even be produced by Martian dust devils.

But as Pan Conrad, deputy principal investigator for SAM says in the video above, the team will continue to explore ways in which methane could be generated and then destroyed in the Martian ecosphere, and make the most of these extremely sensitive instruments that are now on Mars.

“SAM will continue to sniff the Martian atmosphere and look for changes over time,” Conrad said. “That will tell us something about the dynamics between the exchange between the surface and the atmosphere.”

The Sample Analysis at Mars (SAM) instrument, at NASA’s Goddard Space Flight Center, Greenbelt, Md., will analyze samples of material collected by the rover’s arm. Credit: NASA/JPL

SAM: NASA’s Attempt to Repeat Viking’s Search for Martian Organics

After 36 years of debate, confusion, and failed attempts by other space agencies to answer a basic question, NASA’s Mars Science Laboratory (MSL) is on its way to repeat the search for organic matter that eluded the two Viking probes.

With 96 days left until landing, MSL will touch down at the Gale Crater this August. The rover, called Curiosity, will be the largest vehicle delivered to our neighboring planet thus far. Weighing in at 900 kg, Curiosity is nearly five times as large as the Spirit and Opportunity rovers that landed eight years ago, and more than 1.5 times as large as each Viking lander that arrived on planet in 1976.

Like the Vikings and Mars Exploration Rovers, Curiosity was conceived and launched, largely to gather information that may tell us whether the Red Planet harbors microbial life. Instrumentation launched for in situ analysis has been advancing steadily since the Viking era, yet each chapter in the story of the search for Martian life builds upon the previous ones.

Though usually mentioned only briefly in the days when Spirit and Opportunity were making headlines, the twin Viking landers were amazing craft, not only for their time, but even for today. The instrument suite of each Viking lander included a suite of three biology experiments, instruments designed for the direct detection of microbes, should the regolith at either of the two Viking landing sites contain any. While subsequent landing craft have carried instruments designed to assess Mars’ potential for life, none since the Project Viking has been built to look for Martian life forms directly.

According to Viking investigator Gilbert Levin, the Viking landers already discovered Martian life. Back in 1976-1977, Levin’s instrument, known as the Labeled Release (LR) experiment, yielded positive results at Chryse Planitia and Utopia Planitia, the two Viking landing sites. When treated with a solution containing small, organic chemicals labeled with radioactive carbon, regolith samples taken at the landing sites released a gas, indicated by an increase in radioactivity in the space above the sample.

While Levin believes the gas is carbon dioxide resulting from the oxidation of the organic chemicals, it’s also conceivable that the chemicals were reduced to another gas, methane. Either way, since heating the samples to a temperature high enough to kill most of the microbes that we know on Earth prevented the gas release, the Viking science team concluded initially that the LR had detected life.

Most of the science team, but not Levin, decided that the gas release in the LR must have resulted from a non-biological chemical reaction. This rethinking was due to variety of factors, but the most important of which was that the gas chromatograph-mass spectrometer (GC-MS) of each lander failed to detect organic matter in the samples. As the late Carl Sagan explained it on his television series, Cosmos, “If there is life on Mars, where are the dead bodies?”

While most astrobiologists and planetary scientists do not agree with Levin that the results of his 36 year-old experiment constitute conclusive evidence for Martian life, there is a growing number of Mars scientists who are equivocal on the issue. According to Levin, Sagan moved into the equivocal category in 1996, after astrobiologist David McKay and colleagues published a paper in the journal Science describing fossilized life in meteorite ALH84001, one of a handful of meteorites known to be from Mars.

Traveling within Curiosity’s enormous instrument package is a suite of machines called SAM, which stands for “Sample Analysis at Mars”. After all of these years, SAM represents NASA’s first attempt to repeat Viking’s search for Martian organics, but with more advanced technology.

This is not to say that other attempts were not made during the intervening years. In 1996, the Russian Federal Space Agency launched a Mars-bound probe carrying not only organic chemistry equipment but an upgraded version of Levin’s experiment. Rather than treating regolith samples with a mixture of “right-handed” and “left-handed” forms of organic substrates (known in chemistry as racemic mixtures), the new LR would have treated some samples with a left-handed substrate (L-cysteine) and others with the substrate’s mirror image (D-cysteine).

Had results been the same for L- and D-cysteine, a non-biological mechanism would have seemed all the more likely. However, if the active agent in the Martian regolith favored one compound at the expense of the other, this would indicate life. Even more intriguing: if the active agent favored D-cysteine, it would have suggested an origin of life on Mars separate from the origin of life on Earth, since terrestrial life forms use mostly left-handed amino acids. Such a result would suggest that life originates fairly easily, implying a cosmos teaming with living forms.

But Russia’s Mars ’96 probe crashed in the Pacific Ocean shortly after liftoff. A few years later, the European Space Agency sent Beagle 2 to Mars, carrying an advanced organic detection package, but this probe too was lost.

While Curiosity’s SAM does not include an LR experiment of any sort, it does have organic matter detection capability that can operate in mass spectrometry (MS), or gas chromatography-mass spectrometry (GS-MS) mode. In addition to being able to detect certain classes of organic compounds that the Viking GCMS would have missed in surface material, SAM also is designed to look for methane in the Martian atmosphere. Though atmospheric methane already has been detected already from orbit, detailed measurements of its concentration and fluctuations will help astrobiologists to determine whether the source is methane-producing microorganisms.

(Source: universetoday.com)