Now that the ESA has landed on a comet, NASA wants to do them one better: capture an entire asteroid (or a piece of one) and put it in orbit around the moon in 2019. That's the Asteroid Redirect Mission in a nutshell, and the space agency has now said it will put off which form it will take until next year. Option A involved capturing an entire meteorite about 30 feet across, while option B would see them landing on larger target, Philae-style, and digging out a boulder-sized chunk (see the video below). In both cases, the rock will be towed back to the moon and placed in orbit there. Astronauts launching from the upcoming Space Launch System (SLS) in an Orion capsule will then intercept the orbiting meteorite in 2020, retrieve samples and return to Earth.