You know, it's stories like this that convince me that the government knows a little more than it's letting on about an impending asteroid strike. Don't get me wrong: I'm all for them keeping it secret. Things might get a little crazy if word were to get out.
This particular NASA design would use nukes to nudge an asteroid out of the Earth's path. Funny, but they're only proposing 1.2 megaton warheads, albeit on six separate units. Nevertheless, I would have expected larger weapons. But, they're the mathematicians, not me.
The next closest asteroid that we (the public, I mean) know about is the Apophis asteroid that's supposed to pass between the Earth and the Moon in 2029. I understand that in astronomical terms, that's pretty darn close.
I've not always been a 100% fan of NASA, wondering whether it's government's business to explore space. Now, I'm a believer. Give NASA all the funding it needs.