Well, it probably isn't, but an asteroid designated 99942 Apophis is apparently going to make two very close (in astronomical terms, anyway) passes at Earth - once in 2029, and again in 2036. Apparently there's little chance it'll hit Earth in 2029 (about one in 45,000), but astronomers say they need another four to six years to determine the chances of this thing hitting the planet. Right now, they're saying that it shouldn't come closer than 30 million miles on it's second pass, but it's much closer first pass (about 24,000 miles), plus lots of other unknown factors, may change the asteroid's path significantly.
So it sounds like Carter has a few years, if nothing else, to make sure this nuke won't get damaged, requiring last-minute defusing from a space-suited O'Neil.
Full story is here: http://www.foxnews.com/story/0,2933,313561,00.html