Barbelith Underground > Laboratory > Apophis the Destroyer

My preference would be to set up rocket boosters on the surface of Apophis to push it onto a safer course (preferably steering it out of the solar system altogether, but I think that would be a little difficult without using nuclear engines). I believe an alternative to that would be simply to crash an unmanned spacecraft onto it and simply shove it onto a new course. I'd prefer rockets though as they'd make the course change more controllable.

The old trick of setting charges and blowing the rock to hell is a little too risky for my taste, unless of course Apophis is a good distance away from the planet when the bombs go off. Without a comprehensive geological assessment of the asteroid there is a danger of simply splitting it into smaller fragments still capable of entering Earth atmosphere.

Looking at the wiki on Impact Events I noticed this little factoid which made me sit up and go "Ulp!"

The late Eugene Shoemaker of the U.S. Geological Survey came up with an estimate of the rate of Earth impacts, and suggested that an event about the size of the nuclear weapon that destroyed Hiroshima occurs about once a year. Such events would seem to be spectacularly obvious, but they generally go unnoticed for a number of reasons: the majority of the Earth's surface is covered by water; a good portion of the land surface is uninhabited; and the explosions generally occur at relatively high altitude, resulting in a huge flash and thunderclap but no real damage.

Impact Event wiki.

Asteroid Deflection Strategies wiki.

I quite like the idea mentioned in the second link of dusting the rock with titanium oxide to move it by radiation pressure. Same effect as moving it with a solar sail essentially, with perhaps less risk of other objects interfering/damaging it (as micrometeorites would do to a solar sail).