One way to deflect dangerous asteroids into safe orbits is to paint them, according to scientist Dave Hylands.
Hylands proposes painting an asteroid and letting the Sun do the rest. Energy from the Sun would heat the paint, exciting protons. Those prorons would then radiate into space, producing a gentle push on the asteroid. Over time, that push would change the orbit. It's called the Yahofsky effect, after the Russian physicist who worked it out years ago.
NASA is working with Hylands to develop the idea.