Video: Delta 4 lifts off

Hardware for two air-dropped Pegasus XL launchers previously purchased by Stratolaunch, a space launch company founded by the late billionaire Paul Allen, are now back under Northrop Grumman control and for sale to NASA, the Air Force, or commercial satellite operators, industry officials said.

An extended mission for the Falcon 9 rocket’s second stage after launch Thursday with a space station cargo ship helped demonstrate SpaceX’s ability to perform long-duration flight sequences to inject U.S. military payloads directly into high-altitude geosynchronous orbit.

The maiden flight of NASA’s Space Launch System, a heavy-lift human-rated rocket and one of the agency’s core programs, will likely not be ready for takeoff until 2020, officials said recently.