Viking Results Revisited

Image from the Viking 2 lander site. Credit: NASAExperiments prompted by a 2008 surprise result from NASA’s Phoenix Mars Lander suggest that soil examined by NASA’s Viking Mars landers in 1976 may have contained carbon-based chemical building blocks of life. The findings could make a difference in how astrobiologists search for signs of past or present life on the red planet. The only organic chemicals identified when the Viking landers heated samples of Martian soil were chlorine compounds interpreted as contaminants from cleaning fluids. But those chemicals are exactly what researchers found when adding perchlorate (the surprise finding from Phoenix) to desert soil from Chile.