Mastcam mosaic of the Yellowknife Bay formation. This is a view from the base of an exposed section up through Sheepbed, Gillespie Lake, and basal Glenelg members. Locations of drill holes and Alpha Particle X-Ray Spectrometer (A PXS) measurements are shown. Image released Dec. 9, 2013. 
 
 NASA's Curiosity rover has found evidence of an ancient Martian lake that could have supported life as we know it for long stretches — perhaps millions of years. 
 
 This long and skinny freshwater lake likely existed about 3.7 billion years ago, researchers said, suggesting that habitable environments were present on Mars more recently than previously thought. 
 
 "Quite honestly, it just looks very Earth-like," said Curiosity lead scientist John Grotzinger, of the California Institute of Technology in Pasadena. [Ancient Mars Could Have Supported Life (Photos)] 
 
 "You've got an alluvial fan, which is being fed by streams that originate in mountains, that accumulates a body of water," Grotzinger told SPACE.com. "That probably was not unlike what happened during the last glacial maximum in the Western U.S." 
 
 The lake once covered a small portion of the 96-mile-wide (154 kilometers) Gale Crater, which the 1-ton Curiosity rover has been exploring since touching down on the Red Planet in August 2012. 
 
 
 
 Yes - The Red Planet is teeming with tiny microbes, we just haven't found them yet. 
 
 Yes - An advanced civilization lives below the surface, where we can't detect them. 
 
 No - Life never existed on Mars. 
 
 No - Mars once had life, but those organisms are long dead. 
 
 
 
 The main task of Curiosity's $2.5 billion mission is to determine whether Gale Crater could ever have supported microbial life. The rover team achieved that goal months ago, announcing in March that a spot near Curiosity's landing site called Yellowknife Bay was indeed habitable billions of years ago 
 
 The new results, which are reported today (Dec. 9) in six separate papers in the journal Science, confirm and extend Curiosity's landmark discovery, painting a more complete picture of the Yellowknife Bay area long ago. 
 
 This picture emerged from Curiosity's analysis of fine-grained sedimentary rocks called mudstones, which generally form in calm, still water. The rover obtained powdered samples of these rocks by drilling into Yellowknife Bay outcrops. 
 
 The mudstones contain clay minerals that formed in the sediments of an ancient freshwater lake, researchers said. Curiosity also spotted some of the key chemical ingredients for life in the samples, including sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon. 
 
 The lake could have potentially supported a class of microbes called chemolithoautotrophs, which obtain energy by breaking down rocks and minerals. Here on Earth, chemolithoautotrophs are commonly found in habitats beyond the reach of sunlight, such as caves and hydrothermal vents on the ocean floor. 
 
 "It is exciting to think that billions of years ago, ancient microbial life may have existed in the lake's calm waters, converting a rich array of elements into energy," Sanjeev Gupta of Imperial College London, co-author of one of the new papers, said in a statement. 
 
 NASA's Curiosity rover — the centerpiece of NASA's $2.5 billion Mars Science Laboratory (MSL) mission — landed on Mars Aug. 5. How much do you know about Curiosity and its mission? Start the Quiz 0 of 10 questions complete 
 
 A 'Curiosity' Quiz: How Well Do You Know NASA's Newest Mars Rover? NASA's Curiosity rover — the centerpiece of NASA's $2.5 billion Mars Science Laboratory (MSL) mission — landed on Mars Aug. 5. How much do you know about Curiosity and its mission? 0 of questions complete 
 
 The shallow ancient lake may have been about 30 miles long by 3 miles wide (50 by 5 kilometers), Grotzinger said. Based on the thickness of the sedimentary deposits, the research team estimates that the lake existed for at least tens of thousands of years — and perhaps much longer, albeit on a possibly on-and-off basis. 
 
 Taking into account the broader geological context, "you could wind up with an assemblage of rocks that represent streams, lakes and ancient groundwater systems — so for times when the lake might have been dry, the groundwater's still there. This could have gone on for millions or tens of millions of years," Grotzinger said. 
 
 The lack of weathering on Gale Crater's rim suggests that the area was cold when the lake existed, he added, raising the possibility that a layer of ice covered the lake on a permanent or occasional basis. But such conditions wouldn't be much of a deterrent to hardy microbes. 
 
 "These are entirely viable habitable environments for chemolithoautotrophs," Grotzinger said. 
 
 Researchers still don't know if the Gale Crater lake hosted organisms of any kind; Curiosity was not designed to hunt for signs of life on Mars. But if chemolithoautotrophs did indeed dominate the lake, it would put an alien twist on a superficially familiar environment. 
 
 "You can imagine that, if life evolved on Mars and never got beyond the point of chemolithoautotrophy, then in the absence of competition from other types of microbes, these systems might have been dominated by that type of metabolic pathway," Grotzinger said. "And that's an un-Earth-like situation." 
 
 Follow Mike Wall on Twitter @michaeldwall and Google+. Follow us @Spacedotcom, Facebook or Google+. Originally published on SPACE.com. ||||| View Images NASA's Curiosity rover has delivered some cool findings from its trips across the red planet. 
 
 Photograph courtesy NASA/JPL-Caltech/MSSS 
 
 NASA's Curiosity rover, which has been on Mars for almost a year and a half now, just delivered its largest and most important downlink so far of findings, discoveries, and conclusions. (Also see video: "Mission to Mars.") 
 
 While the six papers released by the journal Science report on different aspects of Mars and do it from different scientific perspectives, together they present the beginnings of a new understanding of the red planet, especially in its early epochs, three to four billion years ago. 
 
 Early Mars, it has become increasingly apparent, was in many important ways similar to Earth. (See also "Did Life on Earth Come From Mars?") 
 
 "If you put together all that we're learning about Gale Crater and Mars, you really begin to chip away the rock and the sculpture inside emerges," said Pan Conrad, an astrobiologist with NASA's Goddard Space Flight Center and a co-author on several of the papers. 
 
 As described in the six Science papers, that hidden but slowly materializing landscape looks something like this: 
 
 1. Early Mars was habitable, perhaps for a long time. 
 
 After concluding that rivers and streams once flowed into Gale Crater, the Curiosity team has now reported that a lake existed there as well. That surface water, as well as groundwater that likely went down hundreds of meters, possessed all that was needed to support microbial life. 
 
 The period when Gale Crater was warmer, wetter, and habitable was broadly between 3.5 and 4 billion or more years ago. That period is when life on Earth is understood to have arisen. 
 
 Was Mars once home to primitive extraterrestrial life? Curiosity can't and won't make that determination, but its discoveries have made the possibility of Martian life significantly more plausible. 
 
 2. Water once flowed on many parts of Mars. 
 
 And that water was there at times and in forms that scientists didn't believe to be possible not long ago. 
 
 One of the major achievements of Curiosity so far has been to "ground-truth" observations made in recent years by the satellites orbiting the planet. Those instruments found strong hints that Mars had a watery past, and at Gale Crater they were found to be on target. 
 
 As a result, the mission has given greater credibility to the view that thousands of additional fossil formations of what appear to be ancient streams, channels, deltas, and lakes likely are just what they appeared to be. 
 
 3. "Follow the carbon" has been vindicated. 
 
 The search for Martian carbon-based organic compounds—one of the major goals of the Curiosity mission—has been and will continue to be complicated and trying. 
 
 While as many as six different organic compounds have been identified so far by the miniature chemistry lab called Sample Analysis at Mars (SAM), their origin remain unclear. 
 
 "There's no doubt that SAM has identified organics, but we can't say with confidence yet that they are Martian in origin," said Douglas Ming of NASA's Johnson Space Center, and author of one of the six Curiosity papers in Science. 
 
 There are at least two sources of the confounding results: The presence on Mars of a chlorine-based compound that, when heated in the SAM oven with any organic material, largely destroys the compounds. And the leak into the SAM ovens of an organic solvent brought to Mars as part of a wet chemistry experiment. 
 
 The search for Martian organics is nonetheless making progress. With each collection of Martian sand or rock, the number of organics found and their concentration has increased—suggesting that different samples of Martian material are leading to different results. If the organics were all contaminants from Earth, those concentrations would likely be more steady. 
 
 "SAM is probably the most complex and important instrument ever brought to another planet," Ming said. "Inevitably, it has taken time to figure out how best to work with it." 
 
 4. Mars gets pounded by radiation. 
 
 Galactic cosmic rays and solar eruptions bombard Mars, and their high-energy particles break the bonds that allow organisms to survive. The Radiation Assessment Detector on Curiosity has made the first measurements ever of radiation on the surface of Mars, and the results are sobering. 
 
 In another Science paper, RAD principal investigator Donald Hassler reports that the radiation would almost certainly be fatal within a few million years to any microbial life on the surface or less than several meters deep. 
 
 The RAD team used as their model the terrestrial bacteria Deinococcus radiodurans, which is capable of withstanding enormous doses of radiation, to make that assessment. 
 
 Notwithstanding the high levels of radiation, Hassler reported that life could theoretically still survive on Mars today under special circumstances. If a bacteria similar to D. radiodurans appeared when early Mars was wetter, warmer, and had a more protective atmosphere, he wrote, it could have survived over the epochs through long periods of dormancy. 
 
 5. Mars radiation also damages normal chemistry. 
 
 Many on the Curiosity team point to radiation damage of all carbon chemistry on Mars as a major reason why it has been so difficult to identify organics on the surface. 
 
 That effort, however, may have gotten a significant boost from one of the most unexpected developments to come out of the mission so far―a method to date how long surfaces have been exposed to the sky on Mars. 
 
 Using measurements of radioactive decay also employed on Earth, Kenneth Farley of the California Institute of Technology reports that the surface of Yellowknife Bay has been exposed for some 80 million years. 
 
 The discovery points to a method for finding places for the rover to drill where there has been less chemistry-damaging radiation exposure. 
 
 Essentially, Farley said, the team has to look for cliffs or overhangs being undercut by the surface wind―as happened in Yellowknife Bay―and where radiation would be blocked by the rocks above. "If we find that kind of formation," he said, "drill there." 
 
 6. Detours sometimes turn out to be interesting. 
 
 The Curiosity rover was scheduled to head for the scientifically alluring Mount Sharp in the center of Gale Crater soon after landing. More than 480 days into the mission, the rover is still months away from its prime destination. 
 
 The detour to Yellowknife Bay is the main reason why, and it has turned out to be a gold mine of data. But now the rover is on what is called the "rapid transit route" to three-mile-high Mount Sharp, driving most of the time and passing many potentially interesting sites. ||||| This image from NASA's Curiosity rover shows the first sample of powdered rock extracted by the rover's drill. The image was obtained by Curiosity's Mast Camera on Feb. 20, or Sol 193, Curiosity's 193rd Martian day of operations. 
 
 This story was updated at 3:00 p.m. EST. 
 
 It's official: Primitive life could have lived on ancient Mars, NASA says. 
 
 A sample of Mars drilled from a rock by NASA's Curiosity rover and then studied by onboard instruments "shows ancient Mars could have supported living microbes," NASA officials announced today (March 12) in a statement and press conference. 
 
 The discovery comes just seven months after Curiosity landed on Mars to spend at least two years determining if the planet could ever have hosted primitive life. To be clear, the new find is not evidence that Martian life has ever actually existed; Curiosity carries no life-detection instruments among its scientific gear. 
 
 "A fundamental question for this mission is whether Mars could have supported a habitable environment," said Michael Meyer, lead scientist for NASA's Mars Exploration Program at the agency's headquarters in Washington. "From what we know now, the answer is yes." [The Search for Life on Mars (Photo Timeline)] 
 
 Drilling into Mars 
 
 Curiosity drilled into a rock on Feb. 8, boring 2.5 inches (6.4 centimeters) into an outcrop called John Klein using its arm-mounted hammering drill — deeper than any robot had ever dug into the Red Planet before. 
 
 Two weeks later, the rover transferred the resulting gray powder sample into two onboard instruments called Chemistry and Mineralogy (CheMin) and Sample Analysis at Mars, or SAM. 
 
 CheMin and SAM identified some of the key chemical ingredients for life in this dust, including sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon, researchers said. Intriguingly, the mix also suggested a possible energy source for indigenous Martian life, if any ever existed in the area. 
 
 "The range of chemical ingredients we have identified in the sample is impressive, and it suggests pairings such as sulfates and sulfides that indicate a possible chemical energy source for micro-organisms," Paul Mahaffy, SAM principal investigator at NASA's Goddard Space Flight Center in Greenbelt, Md., said in a statement. 
 
 The fine-grained John Klein rock also contains clay minerals, suggesting a long-ago aqueous environment — perhaps a lake — that was neutral and not too salty, researchers said. 
 
 "We have found a habitable environment that is so benign and supportive of life that probably — if this water was around and you had been on the planet, you would have been able to drink it," said Curiosity chief scientist John Grotzinger, of Caltech in Pasadena. 
 
 Exactly when this water flowed or pooled is unknown, Grotzinger added, though it was likely at least three billion years ago or so. [The Search for Water on Mars (Photos)] 
 
 This set of images shows the results from the rock abrasion tool from NASA's Mars Exploration Rover Opportunity (left) and the drill from NASA's Curiosity rover (right). Note how the rock grindings from Opportunity are brownish red, indicating the presence of hematite, a strongly oxidized iron-bearing mineral. Image released March 12, 2013. Credit: NASA/JPL-Caltech/Cornell/MSSS 
 
 Still looking for complex organics 
 
 SAM is also capable of detecting organic chemicals, the carbon-containing building blocks of life as we know it. 
 
 The instrument detected two simple chlorinated organics at John Klein, chloromethane and dichloromethane, just it did in a scoop of soil late last year at a different site called Rocknest. Mahaffy urged caution in interpreting the recent find, as the John Klein sample was the first one to go through Curiosity's drill. 
 
 "There's always the possibility that some residual carbon that was on the drill bit made its way into the sample," he said. "So we're really looking forward to repeating this experiment and seeing if these signatures of simple chloromethane compounds persist." 
 
 The next drilling opportunity won't come until May, researchers said, since the relative positions of Earth and Mars will make communicating with Curiosity difficult for most of April. 
 
 Curiosity still hasn't found any complex organic compounds — things like amino acids, the building blocks of proteins. That's not necessarily a surprise, researchers said, since such long, complicated molecules tend to be degraded over time, making their detection a challenge, even here on Earth. 
 
 Even if complex organics are absent at John Klein, the site could still have supported life, researchers said. SAM detected carbon dioxide in the drilled sample, showing that the area had a carbon source for putative microbes to tap into. 
 
 Carbon "can be inorganic to be utilized by a microbe," Grotzinger said, pointing out that many micro-organisms on Earth feed on rocks and use carbon dioxide to generate the organics they incorporate into their cellular machinery. 
 
 Still, the rover team will continue searching for spots with a unique set of characteristics — including protection against Mars' relatively high levels of radiation — that could allow organics to be preserved for billions of years. 
 
 "That could take the entire length of this mission, but we're going to give it our best," Grotzinger said. 
 
 This false-color map shows the area within Gale Crater on Mars, where NASA's Curiosity rover landed on Aug. 5, 2012 PDT (Aug. 6, 2012 EDT) and the location where Curiosity collected its first drilled sample at the "John Klein" rock. Image released March 12, 2013. Credit: NASA/JPL-Caltech/ASU 
 
 Troubleshooting a glitch 
 
 Analysis of the drilled sample was complicated by a computer glitch that's still affecting Curiosity today. 
 
 In late February, Curiosity's handlers determined that a glitch had affected the flash memory on the rover's main, or A-side, computer system. So they swapped the rover over to its backup (B-side) computer, which caused the robot to go into a protective "safe mode" on Feb. 28. 
 
 Curiosity emerged from this safe mode on March 2, only to be put on standby briefly once again a few days later to wait out a Mars-bound solar eruption. Full science operations have yet to resume, but Curiosity's B-side computer is working well as engineers continue to work through the mysterious problem with the A-side, team members said. 
 
 "These tests have provided us with a great deal of information about the rover's A-side memory," Jim Erickson, Curiosity deputy project manager at NASA's Jet Propulsion Laboratory in Pasadena, said in a statement. "We have been able to store new data in many of the memory locations previously affected and believe more runs will demonstrate more memory is available." 
 
 Engineers plan to upload two software patches later this week, then reassess when full mission operations can resume, officials said. 
 
 Curiosity landed inside Mars' huge Gale Crater on Aug. 5, kicking off a two-year prime surface mission to determine if the Red Planet has ever been able to support microbial life. CheMin and SAM are two of the 10 instruments it carries to aid this quest. 
 
 While Curiosity has already made a number of interesting discoveries near its landing site — including an ancient streambed where water likely flowed continuously for thousands of years — its main destination is a set of interesting deposits at the base of Mount Sharp, which rises 3 miles (5 kilometers) from Gale's Center. 
 
 Follow Mike Wall on Twitter @michaeldwall. Follow us @Spacedotcom, Facebook or Google+. Originally published on SPACE.com.
– The Curiosity rover has discovered evidence of an ancient freshwater lake on Mars that was brimming with the key chemicals necessary to support microbial life, and its findings suggest that it could have held that life more recently than we thought—and possibly for millions of years before that. "Quite honestly it just looks very Earth-like," the Curiosity's lead scientist said, according to Space.com. The lake, located in the Gale Crater, would have been about 30 miles long and 3 miles wide. The lake's mudstones—which form in calm, still water—contain traces of sulfur, nitrogen, hydrogen, oxygen, phosphorus, and carbon, meaning it could have supported chemolithoautotrophs, a kind of microbial that obtains energy by breaking down rock minerals. The lake was revealed today amidst a barrage of papers on the Rover's progress. National Geographic breaks down some of the other key take-aways, including one that's less promising for Martian life hunters: Curiosity's first radiation measurements indicate levels that would be fatal, within a few million years, to anything within several meters of the surface. Though the researchers did note that some classes of bacteria might have been able to survive through long periods of hibernation.