Why NASA Plans to Grab a Chunk of Asteroid and Move It Closer to the Moon

— -- NASA wants to relocate a piece of an asteroid and tow it into orbit around the moon as part of a test of new technologies that could be used on a manned mission to Mars.

The space agency had considered attempting to capture an entire asteroid, but instead said this week it would pluck a 13-foot boulder from one during an unmanned solar-powered space mission set for 2020.

The rock will then be hauled for several years until it will be placed in orbit around Earth's moon.

In 2025, the space agency said it would then send two astronauts inside the Orion space capsule to explore the mini-asteroid.

According to NASA's plan, the astronauts would take a spacewalk on the rock, documenting its surface and grabbing a fragment to bring back to Earth.

The ambitious mission is a crucial test for the space agency as it prepares to one day send a crew to Mars.

During the five year Asteroid Redirect Mission, NASA is expected to gain more insight into robotic grabbing technologies, soft landings and allow astronauts to test suits that could be used for a deep space mission.

NASA said it likely will not announce which asteroid it has targeted to be a part of the plan until 2019.