Last week, NASA announced the creation of a new office that will take charge in such a scenario.
The Planetary Defense Coordination Office (PDCO) will help to track near-Earth asteroids, develop asteroid deflection strategies, and plan response efforts in case a threat arises.
"While there are no known impact threats at this time," John Grunsfeld from NASA's Science Mission Directorate said in a statement, "the 2013 Chelyabinsk super-fireball and the recent 'Halloween Asteroid' close approach remind us of why we need to remain vigilant and keep our eyes to the sky."
Should a threat arise in outer space (not the alien kind, there's a separate office for that), the PDCO's job will be to coordination communications with the public, assess whether there's anything we can do about it, and coordinate response efforts with FEMA.
Technically NASA would have done all those things anyway, but the new organizational structure formalizes who is in charge in case of an asteroid emergency.
So far we're in no grave danger. NASA estimates that it has found 90 percent of the kilometer-sized, dinosaur-killing asteroids in our general vicinity. The medium-sized asteroids on the order of 450-feet in diameter are harder to spot, but can still cause significant damage.
We've found about 40 percent of those so far, according to Paul Chodas from NASA's Near Earth Asteroid program. With recent increases in funding, NASA's goal is to track down 90 percent of these medium-sized asteroids by 2020.
