According to scientists at
The Keck Institute for Space Studies in California, NASA is seriously considering capturing an asteroid to put in a high orbit around the moon. If the idea is implemented, we could be looking at a manned mission to "capture" an asteroid in the 2020s. This idea is thought to tie in with the Obama administration's enthusiasm for sending a manned mission to a near-Earth asteroid. If NASA were able to capture an object and lock it into an orbit around the moon, it could be safely used as a practise mission without the need for astronauts to move beyond the range of a rescue mission.