John Timmer, for Ars Technica:
A robotic probe will pluck a boulder from the surface of an asteroid and return that, testing our ability to redirect similar rocks if they threaten Earth.
In fact, the entire mission is generally focused on technology development. Once the asteroid is placed in a cis-lunar orbit (orbiting Earth and closer than the Moon), it will be visited by a crewed Orion capsule that will allow detailed study and a return of samples to Earth. But the focus of this mission will be testing technology that will allow extended manned missions in space.
It’s a training exercise with a lot of moving parts. What’s exciting is that NASA scientists have bigger things in mind:
It’s expected that the rock will be in place by late 2025, after which the manned mission will follow using NASA’s Orion spacecraft.
The manned mission will be “in support of advancing the nation’s journey to Mars,” according to NASA. The manipulations of the asteroid’s orbit, in contrast, “will help NASA develop options to move an asteroid off an Earth-impacting course, if and when that becomes necessary.”