NASA is planning to divert an asteroid onto an orbit round the moon in order to use it to train astronauts for a manned trip to Mars sometime in the future. The project has been named ARM (Asteroid Redirect Mission) and is in the early stages of planning. NASA has spent a year and a half developing the plan already.
If all goes according to plan, astronauts on an asteroid in lunar orbit could be gathering samples in ten years. The technology used to carry this out could be used for exploration on Mars. However, there are many differences of opinion on how NASA’s budget should be spent.