Happened to catch rockstar astrophysicist Neil deGrasse Tyson on Charlie Rose the other night and the subject of asteroid deflection came up. For small candidates, vaporization would be ideal. But for larger ones, any attempt at destroying them may have unwanted consequences. Debris fields, partial cleaving, etc. Sending a team of human miners with demolition expertise is not in the cards. So the current vogue in asteroid deflection would be to send something heavy to intercept the asteroid and deflect it a degree or two using only gravitational pull! A very clean and elegant solution that would no doubt make a great simulation or video game ;)<p>Mission Concepts and Operations for Asteroid Mitigation 
Involving Multiple Gravity Tractors<p><a href="http:&#x2F;&#x2F;www.ntrs.nasa.gov&#x2F;archive&#x2F;nasa&#x2F;casi.ntrs.nasa.gov&#x2F;20120013195.pdf" rel="nofollow">http:&#x2F;&#x2F;www.ntrs.nasa.gov&#x2F;archive&#x2F;nasa&#x2F;casi.ntrs.nasa.gov&#x2F;201...</a>