In its ongoing two-year mission to explore Mars for evidence that the planet might once have harbored life, the rover Curiosity has paused to take a deep sniff of the Martian atmosphere, which is 100 times thinner than Earth’s.
The first complete air analysis at the Gale Crater suggest that a fraction of the Martian atmosphere has been lost over billions of years through a physical process that favors retention of heavier isotopes of carbon dioxide gas. The loss of a lighter form of carbon dioxide might have played a significant role in the evolution of the planet, NASA scientists say.
Curiosity's "Sample Analysis at Mars" or SAM instrument package made the most sensitive measurements so far in a search for methane, which could indicate conditions favorable for microbial life. Methane is difficult to detect from Earth or the current generation of Mars orbiters because the gas exists on Mars only in traces, if at all, says Chris Webster of NASA’s Jet Propulsion Laboratory. "At this point in the mission," Webster says,"we’re just excited about searching for it."
Webster added that atmospheric variability in the Martian atmosphere could hold some surprises.
The mission, now in its third month, is set to analyze its first solid soil sample, beginning an ambitious two-year search for organic compounds in the rocks and soils of Gale Crater as well as more atmospheric samples.
According to principal investigator Paul Mahaffy of NASA’s Goddard’s Space Flight Center in Greenbelt, Maryland, "both atmospheric and solid sample analyses are crucial for understanding Mars’ habitability."