Microbial life in desert's arid core is how NASA envisions it on Mars.March 12, 2018
Featuring a remarkably alien landscape, a desert in northern Chile has captured the imagination of NASA scientists who use its harsh conditions to test a next-generation rover and its life-detection equipment for a future mission to Mars.
Perched on a mile-high plateau between the Pacific Ocean and the Andes Mountains, the Atacama Desert is regarded by NASA as the Earth's driest place, baking under high temperatures, low humidity and intense, ultraviolet radiation. Life that survives in the desert's super-arid core exists as microorganisms underground or inside rocks, according to NASA researchers who believe the same would be true on the Red Planet.
"If we ever see life or biomarkers on Mars, it would probably be a very weak and degraded bio-signal, just as we see in this region of the Atacama," said Dr. Brian Glass, principal investigator of NASA's Atacama Rover Astrobiology Drilling Studies (ARADS) project.
Obstacle course for rover
Glass and a team of engineers and scientists recently returned to the Atacama for their third deployment to test the KREX-2 rover, developed by NASA's Ames Research Center in the Silicon Valley, and how it performs with accompanying technology.
"Ground textures, boulders and obstacles, and the total lack of vegetation, make the Atacama site a good testing ground for the rover," Glass said. "The lack of life and lack of biomarkers in the top 2 meters of soil and rocks make this a great place to test sensitive life-detection instruments and methodology."
Of particular interest are the extreme microorganisms living inside Atacama salt habitats, which could be the last refuge for life in this extremely dry region that is otherwise devoid of plants, animals and most types of microorganisms, researchers said.
"We are excited to learn as much as we can about these distinctive, resilient microorganisms and hope that our studies will improve life-detection technology and strategies for Mars," said Mary Beth Wilhelm, a NASA Ames researcher and member of the ARADS science team.
A hotbed of activity
The desert's intense sunshine also makes the Atacama ideal for solar energy generation, with at least six photovoltaic fields going on line since 2014, producing nearly 700 megawatts. Its cloudless nights, free of light pollution, delight astronomers who scan the Southern Hemisphere's skies from a cluster of powerful observatories operated by the European Southern Observatory.
Filmmakers looking for Martian settings noticed the Atacama's extraterrestrial qualities, too, most notably the BBC, which shot in the desert for its 2004 sci-fi drama, "Space Odyssey: Voyage to the Red Planet."
When the NASA team hits the Atacama, its workhorse is the solar-powered KREX-2, a four-wheel vehicle that carries a lightweight, low-power, drill, along with a robotic sample transfer arm. The arm feeds samples brought up by the rover's drill into life-detection instruments positioned nearby. During their 2016 and 2017 desert missions, researchers successfully tested the rover and equipment as stand-alone components, Glass said.
From dirt to data
"The drill, rover and robot arm combination behaved beautifully in the field," Glass said. "This year for the first time we will deploy and test an integrated life-detection rover, carrying both a drill and sample transfer together with three astrobiology instruments." The instruments are:
• The Wet Chemistry Laboratory, which mixes soil with water, adding chemicals and measuring the solution chemistry. NASA's Jet Propulsion Laboratory (JPL) developed the device, one of which flew on the 2007 Phoenix mission to Mars.
• The Signs of Life Detector from Spain's Center for Astrobiology. The instrument searches for more than 500 biological compounds using biochemical methods distantly related to home medical tests, such a blood sugar monitor that detects glucose.
• The Microfluidic Life Analyzer, which the JPL designed to isolate amino acids, a building block of life, from tiny amounts of fluid samples.
"The primary goal of these tests is to demonstrate 'dirt-to-data' autonomously on the rover this year: navigating, drilling, sampling, transfer to instruments, and getting results, in a low-biomass, Mars-like environment with an expected very low biomarker content," Glass said.
Global team hits ghost town
The researchers, who include experts from the U.S., Chile, Spain and France, camp together miles from civilization, working in extremely dry, 90-plus-degree heat with high winds. Their primary work site is Yungay Station, a mining ghost town at one of the driest places in the Atacama and a focal point for astrobiology studies in the last two decades.
After its February 2018 deployment, the team's fourth and final test mission to the desert is expected in early 2019, with the ultimate goal of demonstrating the technical feasibility and scientific value of a mission that searches for evidence of life on Mars, Glass said.
Asked to hazard a guess about when the first human might voyage to Mars, he said: "Probably sometime in the 2030s, unless commercial space firms go there sooner."