Whats needed for planetary defense?

That fireball over puget sound got me thinking. Whats needed for planetary
defense?

If a asteroid plonked down in a major city, and did some major damage, would
that giove nasa a new mission?

If it did what hardware capabilties would be needed? Manned missions to check
out NEA, unmanned pusher vehicles, how to dock or attach to a loose ball of
rocks? theres a million interesting questions about such a earth defense
system.

would we run a couple experiments could push a couple into venus or other
planet and observe the results


HAVE A GREAT DAY!