So is this.....
Maybe a quicker and more economical remedy to the problem would be to send a big load of fresh cow-patties along with thousands of those turd rolling beetles (those little suckers are durable) up to a NEO then gently detonate the delivery vehicle allowing the dung to literally expole all over the face of the asteriod. Since the dung beetles tend to re-conregate with thier booty (little balls of shite) in an elevated region it would aid in weighing down the targeted area thus changing the trajectory of the rock.
Imagine that, a turd roller could save the world.