how much their accident cget the best result possible. we've seen the movie an asteroid comes careening toward earth, threatening all living beings, including ben affleck. well now nasa is preparing for the possibility of it becoming a reality. >> they're preparing to test a spaceship that will intentionally crash into an asteroid. nbc news correspondent tom costello has the story. >> what is this thing? >> it's an asteroid, sir. >> it plays just like a scene out of a disaster movie, nasa's latest mission plans to send a small suas craft on a collision course with an asteroid. >> asteroids have been hitting the earth for billions of years. that's not new. what's exciting and new here is that we're actually taking the first steps to be able to prevent that potentially in the future. and that's where dart comes in. >> reporter: nasa's double