What are the best ways to stop an asteroid heading for the Earth?

Unlike other options that require the precise application of small forces, nuclear explosions would require minimal detailed information about the asteroid while still being effective. This results in a simpler mission design that would only need basic details about the physical characteristics of the asteroid and its trajectory. The mission could also be designed to incrementally deflect the asteroid over multiple blasts which would reduce the overall technical risk of the mission. NASA has already designed the mission and spacecraft required to deflect an asteroid via nuclear explosions.  >Designed by NASA's Marshall Space Flight Center, this latest system would consist of six missile-like interceptor vehicles that would launch aboard an Ares V cargo launch vehicle, each carrying with them a 1.2-megaton B83 nuclear warhead. [source](http://www.engadget.com/2007/08/08/nasa-draws-up-plans-for-nuke-packing-asteroid-interceptor/) >The first vehicle/TRP could be launched, for a stand-off detonation near the NEO, 5h before the last interceptor's release, or the six TRPs could arrive at 1h intervals where the Cradle is 100h from intercept. >The warheads would explode at a distance of one-third of the NEO's diameter and each detonation's X and gamma rays and neutrons would turn part of the NEO's surface into an expanding plasma to generate a force to deflect the asteroid.[source](http://www.flightglobal.com/news/articles/nasa-plans-armageddon-spacecraft-to-blast-asteroid-215924/)

Unlike other options that require the precise application of small forces, nuclear explosions would require minimal detailed information about the asteroid while still being effective. This results in a simpler mission design that would only need basic details about the physical characteristics of the asteroid and its trajectory. Finally t The mission could also be designed to incrementally deflect the asteroid over multiple blasts which would reduce the overall technical risk of the mission. NASA has already designed the mission and spacecraft required to deflect an asteroid via nuclear explosions.  >Designed by NASA's Marshall Space Flight Center, this latest system would consist of six missile-like interceptor vehicles that would launch aboard an Ares V cargo launch vehicle, each carrying with them a 1.2-megaton B83 nuclear warhead. [source](http://www.engadget.com/2007/08/08/nasa-draws-up-plans-for-nuke-packing-asteroid-interceptor/) >The first vehicle/TRP could be launched, for a stand-off detonation near the NEO, 5h before the last interceptor's release, or the six TRPs could arrive at 1h intervals where the Cradle is 100h from intercept. >The warheads would explode at a distance of one-third of the NEO's diameter and each detonation's X and gamma rays and neutrons would turn part of the NEO's surface into an expanding plasma to generate a force to deflect the asteroid.[source](http://www.flightglobal.com/news/articles/nasa-plans-armageddon-spacecraft-to-blast-asteroid-215924/)