'Driest place on Earth' may provide clues to life on Mars

NASA scientists are exploring the "driest place on Earth" that provides a Mars-like environment to study the limits of life, and test drilling and life-detection technologies that may be sent to the red planet in the future.

In a harsh environment with very little water and intense ultraviolet radiation, most life in the extreme Atacama Desert in Chile exists as microbial colonies underground or inside rocks, researchers said.

The cold and dry conditions on Mars open the possibility that evidence for life may be found below the surface where negative effects of radiation are mitigated, in the form of organic molecules known as biomarkers, they said.

However, obtaining samples from below the surface of Mars will require the ability to identify a location of high probability for current or ancient life, place a drill, and control the operation robotically.

Despite being considerably warmer than Mars, the extreme dryness the soil chemistry in the hyperarid core of the Atacama Desert, the "driest place on Earth," are remarkably similar to that of the red planet.

"Putting life-detection instruments in a difficult, Mars-analogue environment will help us figure out the best ways of looking for past or current life on Mars, if it existed," said Brian Glass, a NASA Ames space scientist and the principal investigator of the Atacama Rover Astrobiology Drilling Studies (ARADS) project.

"Having both subsurface reach and surface mobility should greatly increase the number of biomarker and life-target sites we can sample in the Atacama," Glass said.

Scientists worked in extremely dry and hot conditions with high winds during the first ARADS field deployment.

Their work was primarily at Yungay Station, a mining ghost town at one of the driest places in the Atacama.

They also evaluated two other Atacama sites - Salar Grande, an ancient dried-up lake composed of thick beds of salt, and Maria Elena, a similarly extremely dry region - to be considered along with Yungay as the host location for the future ARADS tests in 2017-19.

Scientists put several technologies to test under harsh and unpredictable field conditions: a Mars-prototype drill; a sample transfer arm; the Signs of Life Detector (SOLID); and a prototype version of the Wet Chemistry Laboratory (WCL).

They were successfully used the ARADS drill and sample transfer robot arm at Yungay to acquire and feed sample material to the SOLID and WCL instruments under challenging environmental conditions.

Additionally, researchers from Johns Hopkins University and NASA Ames collected samples for laboratory investigations of the extreme microorganisms living inside salt habitats in the Atacama.

Over the next four years, the ARADS project will return to the Atacama to demonstrate the feasibility of integrated roving, drilling and life-detection, with the goal of demonstrating the technical feasibility and scientific value of a mission that searches for evidence of life on Mars.