The Boston Globe has a good story about NASA’s latest ambitious proposal: sending a crew of astronauts to one of the asteroids by 2025. I imagine they would choose a near-Earth asteroid, and not one from the main belt. Even so, it sounds like a challenging engineering project.
However, I expect that the engineering will be the easy part of this mission. The hard part will be getting enough support from Congress, the President, and ultimately the American people to make it happen.