When the Mars Curiosity made its dramatic and first-of-its-kind landing on Mars in August of 2012, the hope was that the $2.5-billion rover could confirm what scientists had suspected: that there was life on Mars.
Today, in a paper released in the journal Science, researchers explain that if the Red Planet is harboring life, the instruments on the rover have been unable to sniff it out.
NPR's Joe Palca filed this report for our Newscast unit:
"Before Curiosity arrived at Mars a year ago, measurements taken from Earth and from spacecraft orbiting Mars had suggested there was a tiny amount of methane in the thin Martian atmosphere. That's intriguing because methane is produced by living organisms.
"In order to confirm those measurements, one of the instruments aboard the rover was specifically designed to measure what gasses are present on Mars.
"Now, reporting in the journal Science, scientists say they found virtually no methane in six separate air samples analyzed by the rover, less than 1.3 parts per billion if it's there at all making it unlikely that any biological organisms are producing methane on Mars today."
As The New York Times puts it, the findings are "crushing to the popular imagination." It's indisputable that part of the fascination with the Mars Curiosity mission was the potential for an earth-shattering finding.
"That's the mythology," Seth Shostak, a Seti astronomer, told the Times. "Mars is about life, not geology, as interesting as that is. That's the triumph of hope over measurement, and maybe it is."
All of that said, Curiosity, which tweets, sent a missive, keeping longer-term hope alive:
"Lack of methane doesn't mean Mars never supported life. Plenty of Earth organisms don't produce the gas."
Chris Webster of NASA's Jet Propulsion Laboratory and the lead author of the study said: "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. We measured repeatedly from Martian spring to late summer, but with no detection of methane."