Excerpt from sciencedaily.com

Source: NASA/Jet Propulsion Laboratory 

Summary: Experiments prompted by a 2008 surprise from NASA’s Phoenix that soil examined by NASA’s Viking Mars landers in 1976 may have contained carbon- chemical building blocks of life.

Experiments prompted by a 2008 surprise 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.

“This doesn’t say anything about the question of whether or not life has existed on Mars, but it could make a big difference in how we look for evidence to answer that question,” said Chris McKay of NASA’s Ames Research Center, Moffett , Calif. McKay coauthored a by the of Geophysical Research — , reanalyzing results of Viking’s tests for organic chemicals in Martian soil.