Data received from Curiosity has revealed the Martian environment lacks methane. This is a surprise because previous data reported by scientists and various observations indicated positive detections of this gas. 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.
Methane in Martian atmosphere was also detected in the past by sensors of orbital probes. Its existence was confirmed also by data received from European orbiter of red planet – Mars Express. Also some previous spectrographic measurements with use of telescopes on Earth had confirmed that the Methane is present in Martian atmosphere.
Methane could be an evidence of microbial life forms on Mars as its presence could be result of life or volcanic activity. There has not been any volcanic activity detected on Mars, so searching for this gas is one of the targets of more measurements.
SAM which is on board of Curiosity:
sources: JPL NASA