Seeking signs of past life on Mars would be a multi-step process, according to the Science Definition Team for NASA's Mars 2020 mission. The process would begin with using the 2020 rover's instruments to assess whether past conditions were favorable for microbial life and for preserving evidence about Martian life, if it existed. The next step would be searching for possible evidence of any past life, or "potential biosignatures." This search could be done both on Mars, with instruments on the rover, and using laboratories on Earth to examine selected Martian samples returned to Earth. The Mars 2020 rover would collect and package selected samples for possible return to Earth by a future mission. Return of Martian samples for analysis in laboratories on Earth would also enable the next step: recognizing a definitive sign of past Martian life -- a "definitive biosignature."
Image Credit: NASA/JPL-Caltech
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