Live coverage: Station crew lands in Kazakhstan

Pioneering spacecraft from NASA and the Japanese space agency promise to reveal two unexplored asteroids later this year, officials said Wednesday, beginning surveys that will culminate in daring descents to capture samples for return to Earth, where eager scientists await a hands-on look at the specimens.

The International Space Station crew releases the Cygnus OA-7 commercial cargo ship from the Canadian robotic arm to begin free-flight away from the lab complex, completing 43-day visit that delivered supplies, food and science gear.

Mission leaders Tuesday gave approval for rollout of the United Launch Alliance Atlas 5 rocket to its pad on Wednesday morning, leading to liftoff Thursday evening of a NASA probe to rendezvous with an asteroid and bring a sample back to Earth.