The new finding has surprised researchers as previous data reported by US and international scientists had indicated positive detections.
The roving lab 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.
Michael Meyer, NASA's lead scientist for Mars exploration, said that this important result will help them direct their efforts to examine the possibility of life on Mars.
He said that it reduces the probability of current methane-producing Martian microbes, but this addresses only one type of microbial metabolism, as it is a known fact that 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, which is about one-sixth as much as some earlier estimates.
The findings have been published in Science Express.
--ANI (Posted on 20-09-2013)