Can we find evidence of life on Mars?

In 2014, NASA declared that finding evidence for current or past life on Mars is a primary goal. At this writing, the Curiosity rover is still there, doing experiments and analyses. Later rovers are planned for early in the coming decade. In addition, the European Space Agency, collaborating with Russia, is planning to launch several “ExoMars” rovers in the middle of the decade, which will drill 2 m into the surface of Mars to get cores to analyze them for chemical traces of life below the surface. Most exciting, although uncertain, is a Mars Sample Return Mission, in which soil samples will be brought back to Earth for careful experimentation and analysis in laboratories, just as samples from the moon were brought back more than 40 years ago. If you had a Martian soil sample here on Earth, what analyses and experiments would you perform?

Future directions

A daring space mission is in the final planning stages that may provide key information on the origin of life on Earth. There are more than 600,000 known asteroids, most of them rocks from the early solar system orbiting the sun between Mars and Jupiter. But a few thousand have been kicked out of the typical location and are relatively near Earth, some getting closer than our moon. One, called Bennu, was discovered in 1999 and has been well studied. It is just the right size and composition to contain organic molecules. In 2018, a probe called OSIRIS-REx will arrive at the asteroid, spend about a year near it, and collect a sample of material and then return it to Earth in 2023 for analysis. This sample of the early solar system will provide scientists with a window onto not just what the asteroid is made of, but perhaps the earliest molecules that could have led to life.