From sky to soil, the Atacama Desert is the best place to hone the search for extraterrestrial life.
“Penitentes,” unusual snow and ice formations, in Atacama Desert. Image: European Southern Observatory
With its dry climate and high elevation, the Atacama Desert plateau in Chile is one of the best locations on Earth for stargazing. A major hub for astronomical research, the region will soon to be home to the largest ground telescope ever built—a facility so sensitive that it may be able to detect signs of life in the atmospheres of alien worlds.
But it's not just the skies above the Atacama Desert that stand to revolutionize our search for extraterrestrial life. It's also the ground below. Often called the driest place in the world and the subject of punishing ultraviolet radiation, the Atacama Desert is about the closest environment to Mars that you can get, short of schlepping over to the Red Planet.
That's why NASA has been sending expeditions to the desert to field test new life-detecting instruments that will hopefully be bundled into future Martian missions. The latest project— Atacama Rover Astrobiology Drilling Studies (ARADS)—just wrapped its first deployment to Yungay Station, where conditions are particularly reminiscent of Mars.
The ARADs team spent a month braving the bone-dry, gusty environment during the hot Southern hemisphere summer, in order to work out the kinks in NASA's life-detecting toolkit. During their stay, the researchers ran experiments with a Mars-prototype drill, a sample transfer arm, a Signs of Life Detector (SOLID) developed in Spain, and a mock-up of the Wet Chemistry Laboratory (WCL) that accompanied the Phoenix lander to the Martian surface in 2008.
"Putting life-detection instruments in a difficult, Mars-analog environment will help us figure out the best ways of looking for past or current life on Mars, if it existed," said NASA Ames space scientists Brian Glass, who is the principal investigator of the ARADS project, in a NASA statement.
"Having both subsurface reach and surface mobility should greatly increase the number of biomarker and life-target sites we can sample in the Atacama."
Indeed, even during this trip, the team was able to sample three main sites: Yungay, Salar Grande, and Maria Elena. Yungay has been a hotspot for astrobiological studies for over a decade because of its incredibly harsh conditions. Indeed, in 2003, a team tested out the same life-detectors that were onboard the 1975 Viking landers, and found exactly as much life as the original detectors discovered in the Martian soil—zilch. Given that even the most inhospitable regions of Antarctica seem to support extremophile microbes, the abject barrenness of Yungay has made it a popular haunt for astrobiologists ever since.
Salar Grande, meanwhile, is a shimmering salt flat, while Maria Elena has been found to be even drier and more inhospitable than Yungay. Clearly, the ARADs team has a wide range of extraordinary sites to choose from when it comes to developing alien-hunting tools for Mars.
To that point, the team leads will continue returning to the Atacama over the next four years to test out drills, detection kits, and rovers, with the aim of fine-tuning the process of rooting out extremophile organisms, and distinguishing between biotic and abiotic signatures.
Eventually, the descendents of these instruments are expected to voyage to the deserts of Mars, where they will repeat the drill, so to speak. These efforts may provide scientists with the first hard evidence of life, past or present, beyond Earth.
Alternatively, Atacama's astronomers may be the ones that stumble across hard evidence of biological entities inhabiting farflung planets in the Milky Way, through the apertures of the super-telescopes that call the plateau home.
Only time will tell, but regardless, this singular Chilean desert is shaping up to be the ace in the hole when it comes to the search for extraterrestrial life.