An asteroid the size of an aircraft carrier passed within the moon's orbit Tuesday, the closest approach by an object that large in more than 30 years.

Asteroid 2005 YU55 passed within 202,000 miles of Earth - about four-fifths of the distance to the moon - at 6:28 p.m. Tuesday, NASA said.

Marina Brozovic, a researcher at NASA's Jet Propulsion Laboratory in California, said the space agency was able to train a great deal of high-powered instruments - including the massive radio telescope at Arecibo, Puerto Rico - on the asteroid as it approached.

"This is a rare event, and we learned a lot," Brozovic told CNN.

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