I think the facts are off a bit. This meteor weighed in the neighborhood of 7000 metric tons, not 10 tons. The energy released was not equivalent to Tunguska; Tunguska was not "a little higher", it was 50 times greater.
The Independent reported the mass as 10 tons. Do you have a source for the 7000 ton number? (Are you sure it wasn't 7000 kilograms? That's about ten tons.)
If you care about the future of civilization, it might be best to avoid supporting the borrowing of even more $trillions for a tiny chance at preventing a killer asteroid that likely won't happen before the next ice age destroys most of the world's major cities (unless global warming prevents it, I suppose).
