Nasa's Asteroid Redirect Mission Sets Sights on Mars

In a statement, Nasa also announced that it has increased the detection of near-Earth asteroids by 65 percent since launching its asteroid initiative three years ago.

"The ARM will provide an initial demonstration of several spaceflight capabilities we will need to send astronauts deeper into space, and eventually to Mars," said Nasa associate administrator Robert Lightfoot.

For ARM, a robotic spacecraft will capture a boulder from the surface of a near-Earth asteroid and move it into a stable orbit around the moon for exploration by astronauts, all in support of advancing the nation's journey to Mars.

The option to retrieve a boulder from an asteroid will have a direct impact on planning for future human missions to deep space and begin a new era of spaceflight.

The agency plans to announce the specific asteroid selected for the mission no earlier than 2019, approximately a year before launching the robotic spacecraft.

Nasa has identified three valid asteroids for the mission so far: Itokawa, Bennu and 2008 EV5.

The agency expects to identify one or two additional candidates each year leading up to the mission.

Following its rendezvous with the target asteroid, the uncrewed ARM spacecraft will deploy robotic arms to capture a boulder from its surface.

It will then begin a multi-year journey to redirect the boulder into orbit around the moon.

Throughout its mission, the ARM robotic spacecraft will test a number of capabilities needed for future human missions, including advanced Solar Electric Propulsion (SEP).

It is a valuable capability that converts sunlight to electrical power through solar arrays and then uses the resulting power to propel charged atoms to move a spacecraft.

"Asteroids are a hot topic. Not just because they could pose a threat to Earth, but also for their scientific value and Nasa's planned mission to one as a stepping stone to Mars," added Jim Green, director of Nasa Planetary Science.