Last week’s launch of the Mars 2020 Mission with the Perseverance rover—NASA’s heaviest and most advanced rover to date—moved the return of samples from Mars one giant step forward, as the rover is slated to collect Martian soil to be picked up later this decade and brought back to Earth for detailed analysis. Efforts to search for current life on Mars have also moved forward; results of a conference held last November in Carlsbad, New Mexico, called “Mars Extant Life: What’s Next?”, have just been published in the journal Astrobiology.
Many scientists at that meeting, and in the scientific community at large, think there is a realistic possibility that life exists on Mars today. If that’s true, where should we search for it? The participants agreed there are four principal potential habitats for Martian life: within salt rocks, within ice, in caves, and in the deep subsurface. During the meeting the pro and cons of each of those habitats, and how they could best be searched, was discussed. The final workshop report shies away from prioritizing one habitat or detection method over another. But the participants agreed that the time has come to search for active life on the Red Planet.
Both approaches, Mars sample return and life detection, are the subject of advocacy “white papers” submitted to the National Academy of Sciences Decadal Survey for planetary exploration. These white papers will be evaluated by NASA’s Science Mission Directorate to determine funding priorities for planetary exploration for at least the next 10 years. Here again, a consensus seems to be emerging that it’s time to address the question of whether there is indigenous life on Mars. This is critical to know before human missions are launched to the planet.
With all this happening, I believe we’re now entering a new age of Mars exploration, where we transition from looking for liquid water and organic molecules to more directly tackling the question of life on Mars. To answer the question properly, we need both samples from Mars and in-situ life detection studies on the surface, before samples lose their chemical or biological reactivity during the long trip back to Earth—one of many lessons learned from the ambiguous Viking life detection experiments in the late 1970s.
Personally, I would have wanted a life detection mission that returned samples immediately to Earth without waiting for a future mission. But I find it remarkable that NASA held to the 2020 launch schedule despite the COVID-19 pandemic. For that I think the entire project team deserves our admiration.