A methane spike seen in the atmosphere of Mars may have been caused by the Curiosity rover, according to NASA researchers. Readings have previously been recorded by spacecraft orbiting the Red Planet, and astronomers on Earth reported detecting clouds of methane in the Martian atmosphere in 2003 and 2004. These seemed to disappear a few years later, leading astronomers to question whether the findings were flawed.
The Curiosity rover was designed, in part, to determine if methane is present in the atmosphere of Mars. Between October 2012 and June 2013, the rover was utilized to take six samples of the atmosphere, none of which showed evidence of the gas.
In December 2014, NASA announced a methane spike had been recorded in four samples taken in late 2013 by the Curiosity rover. On Earth, methane is usually created as a by-product of biological processes, so this finding excited some researchers who believed microbes might soon be found on the alien landscape. However, some researchers are critical of the results, believing the reading to be in error.
"I am convinced that they really are seeing methane. But I'm thinking that it has to be coming from the rover," Kevin Zahnle from the Ames Research Center said. Ames in California is one of 10 NASA field enters; it does research and development in aeronautics, exploration technology and science.
The Curiosity rover contains methane within an internal chamber, at concentrations 1,000 times higher than that needed to account for the readings, Zahnle told the press. He was also critical of the findings recorded by astronomers more than a decade ago. Mission engineers tell reporters that although concentrations in the chamber are high, there is not enough methane in the system to trigger the observed readings.
"We are continuously monitoring that methane amount and there hasn't been evidence of any leakage during the entire mission.... To produce the amount we detected in Mars's atmosphere, you'd need a gas bottle of pure methane leaking from the rover. And we simply don't have it," said Chris Webster of NASA's Jet Propulsion Laboratory.
The Mars Curiosity team is planning to take an additional series of readings at the end of 2015. This will be one Martian year after methane was supposedly detected by the spacecraft. If the gas is seen once again, then the source would likely be seasonal, which would suggest a biological origin. Such a finding would also make it unlikely that Curiosity is the source of the gas.
The ExoMars Trace Gas Orbiter (TGO), designed by the European Space Agency, is scheduled for launch in 2016. Once it arrives at the Red Planet, the spacecraft will be capable of examining the atmosphere of Mars for signs of the elusive gas. Finding methane on Mars could be the first positive sign of alien life, or maybe just odd chemistry.