NASA released their plan as part of their FY2014 budget...

NASA released their plan as part of their FY2014 budget proposal to capture an asteroid in 2019, tow it into orbit, and send astronauts to explore the surface.

They say that performing all the elements for the proposed asteroid initiative “integrates the best of NASA’s science, technology and human exploration capabilities and draws on the innovation of America’s brightest scientists and engineers.” The mission will combine existing technology along with capabilities being developed to find both large asteroids that pose a hazard to Earth and small asteroids that could be candidates for the proposed mission. NASA says this initiative will help accelerate technology development activities in high-powered solar electric propulsion and take advantage the Space Launch System rocket and Orion spacecraft currently being built, “helping to keep NASA on target to reach the President’s goal of sending humans to Mars in the 2030s.”