Mars Rover Curiosity Measures Red Plant's Air Quality, Finds Evidence of Large Gas Escape

Mars likely lost a majority of its original atmosphere to space a long time ago, researchers have announced.

Curiosity, the robotic, roving probe sent to the Red Planet by the national Aeronautics and Space Administration, has discovered traces of argon gas in the thin Martian air, seeming to support the longstanding belief the current atmosphere there is just a remnant of what it once was.

"We found arguably the clearest and most robust signature of atmospheric loss on Mars," Sushil Atreya, a co-investigator with the Sample Analysis at Mars (SAM) program  at the University of Michigan, said in a statement.

A SAM device attached to Curiosity sampled some Martian air, which is only about which is just 1 percent as thick as that of Earth.

The instrument measured the ratio of different chemicals still present in the Mars atmosphere. That data from that testing seemed to be consistent with the notion gases escaped from the top of the Martian atmosphere sometime in the distant past, with lighter atoms and molecules lifting into space more readily than heavier ones.

The Curiosity rover team reported their finidngs about the Martian atmosphere, along with other observations made by the probe, at the 2013 European Geosciences Union General Assembly today in Vienna.

Curiosity's onboard weather station, the Rover Environmental Monitoring Station, or REMS, has shown humidity varies, along the robot's route inside Mars' huge Gale Crater.

As well, Curiosity has used its laser-shooting Chemistry and Camera instrument, or ChemCam, to examine the coating of dust that gives the Red Planet its distinctive color.

"We knew that Mars is red because of iron oxides in the dust," Sylvestre Maurice, ChemCam's deputy principal Investigator from the Research Institute of Astrophysics and Planetology in Toulouse, France, said in a release. "ChemCam reveals a complex chemical composition of the dust that includes hydrogen, which could be in the form of hydroxyl groups or water molecules."

Curiosity landed inside Gale Crater Aug. 5, starting a two-year surface mission to determine if the area could have ever supported microbial life --- and that goal was apparently already reached when it was announced last month an area called Yellowknife Bay showed indications it was a wet, habitable environment billions of years ago.

But any new discoveries will have to wait until May, after Mars passes from behind the sun, out of range of Earth signals. Curiosity won't receive any new commands for the next four weeks or so.

So, until May 1, the rover will remain stationary, but still carry out research commands it was sent in March