I’m a bit surprised at this result from Curiosity. It appears that measurements from Mars orbiters indicating the presence of methane in the atmosphere were wrong:

Mars Science Laboratory: NASA Curiosity Rover Detects No Methane On Mars

PASADENA, Calif. — Data from NASA’s Curiosity rover has revealed the Martian environment lacks methane. This is a surprise to researchers because previous data reported by U.S. and international scientists indicated positive detections.

The roving laboratory performed extensive tests to search for traces of Martian methane. Whether the Martian atmosphere contains traces of the gas has been a question of high interest for years because methane could be a potential sign of life, although it also can be produced without biology.

“This important result will help direct our efforts to examine the possibility of life on Mars,” said Michael Meyer, NASA’s lead scientist for Mars exploration. “It reduces the probability of current methane-producing Martian microbes, but this addresses only one type of microbial metabolism. As we know, there are many types of terrestrial microbes that don’t generate methane.”

Curiosity analyzed samples of the Martian atmosphere for methane six times from October 2012 through June and detected none. Given the sensitivity of the instrument used, the Tunable Laser Spectrometer, and not detecting the gas, scientists calculate the amount of methane in the Martian atmosphere today must be no more than 1.3 parts per billion. That is about one-sixth as much as some earlier estimates. Details of the findings appear in the Thursday edition of Science Express.

“It would have been exciting to find methane, but we have high confidence in our measurements, and the progress in expanding knowledge is what’s really important,” said the report’s lead author, Chris Webster of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “We measured repeatedly from Martian spring to late summer, but with no detection of methane.”

Webster is the lead scientist for spectrometer, which is part of Curiosity’s Sample Analysis at Mars (SAM) laboratory. It can be tuned specifically for detection of trace methane. The laboratory also can concentrate any methane to increase the gas’ ability to be detected. The rover team will use this method to check for methane at concentrations well below 1 part per billion.

Methane, the most abundant hydrocarbon in our solar system, has one carbon atom bound to four hydrogen atoms in each molecule. Previous reports of localized methane concentrations up to 45 parts per billion on Mars, which sparked interest in the possibility of a biological source on Mars, were based on observations from Earth and from orbit around Mars. However, the measurements from Curiosity are not consistent with such concentrations, even if the methane had dispersed globally.

“There’s no known way for methane to disappear quickly from the atmosphere,” said one of the paper’s co-authors, Sushil Atreya of the University of Michigan, Ann Arbor. “Methane is persistent. It would last for hundreds of years in the Martian atmosphere. Without a way to take it out of the atmosphere quicker, our measurements indicate there cannot be much methane being put into the atmosphere by any mechanism, whether biology, geology, or by ultraviolet degradation of organics delivered by the fall of meteorites or interplanetary dust particles.”

The highest concentration of methane that could be present without being detected by Curiosity’s measurements so far would amount to no more than 10 to 20 tons per year of methane entering the Martian atmosphere, Atreya estimated. That is about 50 million times less than the rate of methane entering Earth’s atmosphere.

Curiosity landed inside Gale Crater on Mars in August 2012 and is investigating evidence about habitable environments there. JPL manages the mission and built the rover for NASA’s Science Mission Directorate in Washington. The rover’s Sample Analysis at Mars suite of instruments was developed at NASA’s Goddard Space Flight Center in Greenbelt, Md., with instrument contributions from Goddard, JPL and the University of Paris in France.

For more information about the mission, visit http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl . To learn more about the SAM instrument, visit: http://ssed.gsfc.nasa.gov/sam/index.html .

The latest on Curiosity’s trek towards Mount Sharp:

Mars Science Laboratory: Long Drive Puts NASA Mars Rover Near Planned Waypoint

PASADENA, Calif. — NASA’s Mars rover Curiosity now has a view of a patch of exposed bedrock scientists selected for a few days of close-up study, the first such study since the rover began its long trek to Mount Sharp two months ago.

Curiosity reached the crest of a rise informally called “Panorama Point.” From Panorama Point, the rover took photographs of a pale-toned outcrop area that the team chose earlier as “Waypoint 1” on the basis of imagery from NASA’s Mars Reconnaissance Orbiter.

Five selected waypoints dot the mission’s route southwestward from the “Glenelg” area, where Curiosity worked during the first half of 2013, and an entry point to the lower layers of Mount Sharp, the mission’s next major destination. Waypoint 1 lies about one-fifth of the way along the approximately 5.3-mile (8.6-kilometer) route, as plotted from examining orbiter images.

Curiosity advanced 464 feet (141.5 meters) on Sept. 5 in the longest one-day drive so far in the 13-month-old mission. The drive toward the elevated Panorama Point combined two segments. For a long initial segment, engineers chose the path from images examined on Earth ahead of time. That was followed by a 138-foot (42-meter) segment, for which the rover autonomously navigated its own path based on images taken during the day’s drive. That Sept. 5 drive plus the next one — 80 feet (24.3 meters) on Sept. 8 — brought the rover to the top of Panorama Point.

For the Sept. 5 drive, “we had a long and unobstructed view of the hill we needed to climb, which would provide an overlook of the first major waypoint on our trek to Mount Sharp,” said Jeff Biesiadecki, a rover planner on the Curiosity team at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “We were able to extend the drive well beyond what we could see by enabling the rover’s onboard hazard avoidance system.”

In the Glenelg area, Curiosity accomplished the mission’s major science goal by finding evidence of an ancient environment favorable for microbial life. The evidence came from analysis of rock powder drilled from two outcrops in a shallow depression called “Yellowknife Bay.” When the rover examines multiple rock layers of Mount Sharp, researchers hope to learn more about ancient habitable environments and major changes in environmental conditions.

“We want to know how the rocks at Yellowknife Bay are related to what we’ll see at Mount Sharp,” said the mission’s project scientist, John Grotzinger of the California Institute of Technology, Pasadena. “That’s what we intend to get from the waypoints between them. We’ll use them to stitch together a timeline — which layers are older, which are younger.”

The science team is using images taken from Panorama Point to select precisely where to pause for a few days and use instruments on Curiosity’s arm to examine Waypoint 1. The rock targets being considered are still about 245 feet (75 meters) southwest of Curiosity’s Sept. 9 position.

The trek to Mount Sharp will continue for many months after the planned work at Waypoint 1.

NASA’s Jet Propulsion Laboratory, a division of Caltech in Pasadena, manages the Mars Science Laboratory Project for NASA’s Science Mission Directorate, Washington. JPL designed and built the project’s Curiosity rover.

More information about Curiosity is online at http://www.nasa.gov/msl and http://mars.jpl.nasa.gov/msl/ . You can follow the mission on Facebook at http://www.facebook.com/marscuriosity and on Twitter at http://www.twitter.com/marscuriosity .

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Curiosity’s View from ‘Panorama Point’ to ‘Waypoint 1’ and Outcrop ‘Darwin’

NASA’s Mars rover Curiosity captured this view using its Navigation Camera (Navcam) after reaching the top of a rise called “Panorama Point” with a drive during the 388th Martian day, or sol, of the rover’s work on Mars (Sept. 8, 2013). The view is southwestward and spans approximately from south to west, left to right.

In the upper central portion of the image is a patch of ground paler than its surroundings. This pale-toned patch had been mapped from orbit and selected as the first of a few waypoints for the rover to study for a few days during pauses in the mission’s multi-month trek from the “Glenelg” area to the lower layers of Mount Sharp. The outcrop that is exposed at this “Waypoint 1” site has been informally named “Darwin.” It is about 245 feet (75 meters) from the rover’s Sol 388 position on Panorama Point.

Curiosity finished more than six months of investigations in the Glenelg area in early July 2013 and began the drive of about 5.3 miles (8.6 kilometers) from Glenelg to the Mount Sharp entry point. Waypoint 1 is about one fifth of the way along the route plotted from examining orbiter images.