Countdown to Impact

For the first time in the history of space exploration, scientists spotted and tracked an asteroid on a collision course with Earth. About the size of a truck, the asteroid slammed into the Nubian Desert in Sudan, in nearly the exact spot and only a few seconds from the time scientists had predicted. Now, together with NASA scientists, National Geographic joins researchers as they examine the remnants of the asteroid to unlock the clues to help US prevent or survive a future incident.