U.S., SpaceX focus on 2nd stage engine to wrap up certification
March 23, 2015 at 22:38 PM EDT
WASHINGTON, March 23 (Reuters) - The U.S. Air Force said on Monday it was on track to certify privately held SpaceX to launch U.S. military and spy satellites by June, with the final efforts focused on qualifying the second stage engine and structure of its Falcon 9 rocket.
