Asteroid deflection. Computer artwork of an astronaut landing on an asteroid to deflect it from its collision course with Earth. The astronaut will place a solar-powered engine on the asteroid's surface, which will gently push the asteroid from its course. The asteroid would need to be spotted years before any impact, as the deflection would take several months. Pushing an asteroid off course is preferable to destroying it, as many asteroid fragments hitting Earth could be more catastrophic than a whole asteroid impact.