The Pentagon’s Defense Advanced Research Projects Agency says it has selected the Boeing Co. to develop and test its XS-1 hypersonic space plane, using a design now known as the Phantom Express.

Boeing won out over Northrop Grumman and Masten Space Systems to take the long-running XS-1 project beyond Phase 1 into Phase 2/3, culminating with test flights in 2020.

The reusable space plane would be designed to carry and deploy a small, expendable upper stage, then return to Earth for a runway landing. The upper stage would be capable of putting satellites weighing up to 3,000 pounds in low Earth orbit.

“Phantom Express is designed to disrupt and transform the satellite launch process as we know it today, creating a new, on-demand space-launch capability that can be achieved more affordably and with less risk,” Darryl Davis, president of Boeing Phantom Works, said today in a statement.

DARPA will provide up to $146 million for the project. Boeing said it would invest jointly with DARPA in the plane’s development, but declined to give a specific figure for its contribution.

Boeing and the Air Force already have tested a reusable space plane known as the X-37B four times. The most recently flown X-37B landed earlier this month after spending nearly two years in orbit.

Boeing had partnered with Blue Origin on rocket engine studies during Phase 1 of the XS-1 project, but for Phase 2/3, the company will go with Aerojet Rocketdyne’s AR-22 engine, which is based on the design for the space shuttle main engines.

“As one of the world’s most reliable rocket engines, the SSME is a smart choice to power the XS-1 launch vehicle,” Aerojet Rocketdyne CEO and President Eileen Drake said in a statement. “This engine has a demonstrated track record of solid performance and proven reusability.”

Phase 2 of the XS-1 project calls on Boeing to complete its design for the Phantom Express and conduct ground tests by 2019. One of the key ground tests calls for firing the rocket engine 10 times over consecutive 10 days.

Phase 3 would involve 12 to 15 flight tests, currently scheduled for 2020. One objective is to have the XS-1 fly 10 times over 10 consecutive days to demonstrate reusability with a rapid turn-around. Subsequent test flights would fly as fast as Mach 10, and deliver a demonstration payload weighing between 900 pounds and 3,000 pounds into low Earth orbit.

DARPA said one of its aims was to encourage the rise of commercial launch services that could operate with recurring costs of $5 million or less per launch. Toward that end, DARPA plans to release selected data from its Phase 2/3 tests and share relevant payload specifications with commercial ventures.

“We’re delighted to see this truly futuristic capability coming closer to reality,” Brad Tousley, director of DARPA’s Tactical Technology Office, said in the agency’s news release. “Demonstration of aircraft-like, on-demand, and routine access to space is important for meeting critical Defense Department needs and could help open the door to a range of next-generation commercial opportunities.”