Zothecula writes "To paraphrase an old saying, if the astronaut can't go to the asteroid, then the asteroid must come to the astronaut. In a study released by the Keck Institute for Space Studies, researchers outlined a mission (PDF) to tow an asteroid into lunar orbit by 2025 using ion propulsion and a really big bag. The idea is to bring an asteroid close to Earth for easy study and visits by astronauts without the hazards and expense of a deep space mission. Now, Keck researchers say NASA officials are evaluating the plan to see whether it's something they want to do. The total cost is estimated to be roughly $2.6 billion."