A trio of astronauts from the Return to Flight crew train for their flight by floating in NASA's famed KC-135 aircraft.

From left, mission specialists Stephen K. Robinson, Charles J. Camarda, and Soichi Noguchi of the Japan Aerospace Exploration Agency (JAXA), experience brief weightlessness as the plane flies a series of climbs and dives -- called "parabolas" -- over the Gulf of Mexico.

Robinson, Camarda, Noguchi and their four crewmates are set to take the orbiter Discovery to the International Space Station on mission STS-114, targeted for a launch opportunity beginning in May.

Image Credit: NASA