The agency will name its target asteroid in 2019, a year before the ARM spacecraft is scheduled to launch. It's eyeing Itokawa, Bennu and 2008 EV5 at the moment, but it's still looking for more viable candidates. Once it finds its target, the spacecraft will spend 400 days circling the asteroid to test a technique that could prevent one from crashing into Earth. No, not drilling and embedding an explosive into it, but using the spacecraft's gravitational field to alter the asteroid's orbit. After that, the vehicle will deploy a robotic arm to the surface of the celestial object to dig up a boulder, and then embark on a six-year journey to bring the sample rock to the moon's orbit.

The mission doesn't end there, though. In mid-2020s, after the boulder reaches its destination, NASA will send a manned spacecraft aboard the SLS rocket to rendezvous with and collect samples from it. At the moment, the agency's planning to deploy a two-person crew to the site for 25 days, but that might change when the time comes. That will serve as some sort of trial phase for the astronauts, giving them ideas on how to best collect and return samples from Mars.

[image credit: GETTY/Elenarts]