Astronomers have identified an asteroid small enough to be potentially suitable for NASA's mission to capture such a body.
NASA plans to use a robotic spacecraft to either net a small asteroid or grab a rock off a larger one, before dragging the body into lunar orbit for study. Michael Mommert at Northern Arizona University in Flagstaff and his colleagues studied the asteroid known as 2011 MD using the infrared camera on NASA's Spitzer Space Telescope. The team estimated the rocky body to be just 6 metres across and remarkably porous — made up of around 65% empty space, like a pile of rubble.
The mass and density of 2011 MD make it a valid candidate for a mission that grabs a whole asteroid, the third candidate identified so far.