A Tough Row to Hoe for Early Martian Microbes

"The [Mars Science Laboratory on the Curiosity rover] was never prepared for looking for signs of life," she said. "The Curiosity rover's instruments are designed so that scientists could answer the questions of whether it's possible for life to have existed in the past and whether any traces would be detectable. The challenges for living things on Mars started billions of years ago, when the planet, for whatever reason, lost its magnetic field, Eigenbrode said.