NASA spacecraft touches surface of asteroid

A NASA spacecraft descended to an asteroid Tuesday and, dodging boulders the size of buildings, momentarily touched the surface to collect a handful of cosmic rubble for return to Earth.

It was a first for the United States _ only Japan has scored asteroid samples.

"Touchdown declared," a flight controller announced to cheers and applause. "Sampling is in progress."

Confirmation came from the Osiris-Rex spacecraft as it made contact with the surface of the asteroid Bennu more than 200 million miles away.

But it could be a week before scientists know how much, if much of anything, was grabbed and whether another try will be needed. If successful, Osiris-Rex will return the samples in 2023.

Osiris-Rex took 4 1/2 hours to make its way down from its tight orbit around Bennu, following commands sent well in advance by ground controllers near Denver.

Bennu's gravity was too low for the spacecraft to land _ the asteroid is just 1,670 feet (510 meters) across. As a result, it had to reach out with its 11-foot (3.4-meter) robot arm and attempt to grab at least 2 ounces (60 grams) of Bennu.