CAPE CANAVERAL, Fla. — A 150-foot asteroid hurtled toward Earth's backyard, destined Friday to make the closest known flyby for a rock of its size.

NASA promised the asteroid would miss Earth by 17,150 miles, avoiding catastrophe. But that's still closer than many communication and weather satellites; scientists insisted these, too, would be spared.

Asteroid 2012 DA14, as it's called, is too small to see with the naked eye even at its closest approach around 2:25 p.m. EST, over the Indian Ocean near Sumatra.