Well, someday maybe. NASA is now tracking more than 800 asteroids considered potential threats to the Earth. According to a New Scientist article, engineers brainstorming ways to save the Earth have proposed sending a fleet of suicidal robots to the asteroid. Some of the robots would land on the asteroid and detonate explosives. The remaining probes would monitor the explosions to determine the inner structure of the asteroid. If it's light enough, a gravity tractor robot would deflect it. If it's heavy and solid, rocket engines would be attached to alter its path. Up to six 12kg, low-cost robots could be launched on a single spacecraft. For more details on the robot probes see the Ball Aerospace news release.