In 2020 NASA is going back to Mars. They're sending a second rover, built on the same base as the successful Curiosity but carrying different instruments and working toward different goals. NASA isn't quite sure yet where on the planet Curiosity's successor will head, but whatever spot the agency chooses will be hugely important: part of the new rover's tentative mission is to collect rocks that will then be returned to Earth, says Alexandra Witze for Nature.
Scientists have talked for decades about getting their hands on Martian rocks to look for signs of past life. They have studied meteorites that originated on Mars, but no space agency has yet been able to bring back samples directly, in part because of the cost and in part because of technical failures.
NASA's new rover should hopefully finally give scientists a chance to get their hands dirty (through protective, contamination-free gloves, of course) in red Martian soil. According to Witze, if all goes to plan—and with budgetary constraints that's always a big if—the new rover will be the first step of a complicated relay race to shuttle rocks from the Martian surface back to Earth, a trip that could involve as many as three different missions and four different robots:
NASA’s plan for bringing back Martian samples would involve a succession of missions over many years (see ‘Fetch!’). Step one would need a rover to collect and store roughly 30 narrow cylinders of rock and soil, either on board or on the ground. In step two, an unmanned rocket would fly to Mars and deploy another rover to fetch the samples and then blast them into orbit. Step three would be to capture that orbiting package and fly it back to Earth.
It will still be many years before blast off, but these are exciting times. The detail and accuracy, and the array of tests that scientists could do on the Mars rocks with advanced laboratories down here in the ground, blow out of the water anything that could be carried aboard a rover. Looking for signs of ancient life is a difficult scientific gambit, so having samples on hand that can be tested with the latest advances in laboratory equipment is a huge boon.