For the last few years, the US military has been looking to make an entirely new hypersonic spaceplane — one that can be reused frequently over a short period of time to deliver multiple satellites into orbit. And now the Department of Defense has picked Boeing to turn that spaceplane into a reality. DARPA, the agency that tests new advanced technologies for the military, has picked Boeing’s design concept, called the Phantom Express, to move forward as part of the agency’s Experimental Spaceplane (XS-1) program. That means DARPA will work together with Boeing to build and test out the company’s vehicle.

The goal of DARPA’s XS-1 program is to create a spacecraft that’s something of a hybrid between an airplane and a traditional vertical rocket. The spaceplane is meant to take off vertically and fly uncrewed to high altitudes above Earth. From there, the vehicle will release a mini-rocket — a booster with an engine that can propel a satellite weighing up to 3,000 pounds into orbit. As the booster deploys the satellite, the spaceplane will then land back on Earth horizontally just like a normal airplane — and then be fueled up for its next mission. DARPA wants the turnaround time between flights to last just a few hours.

A hybrid between an airplane and a traditional vertical rocket

But perhaps the most audacious goal is the price DARPA wants for each flight. The agency is aiming for the spaceplane to cost $5 million per mission, a significant bargain considering most orbital rockets cost tens to hundreds of millions of dollars to launch. And Boeing says it’s up to the task. “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 in a statement.

Boeing was one of three companies vying for the chance to build a spaceplane for XS-1. The other two contenders included Northrop Grumman Corporation and Masten Space Systems. The three companies had all been awarded contracts through Phase 1 of the XS-1 program to determine the feasibility and methods needed to make such a frequently reused spaceplane possible. The three companies each paired up with a commercial launch provider to come up with their designs: Northrop paired with Virgin Galactic, Masten with XCOR Aerospace, and Boeing with Jeff Bezos’ company Blue Origin.

Though it looks like Boeing has decided to go with a different company to make the propulsion system for its spaceplane. The vehicle will use an AR-22 engine, manufactured by Aerojet Rocketdyne, instead of an engine from Blue Origin. The AR-22 is roughly the same type of engine used to power the Space Shuttle, according to Aerojet. “This engine has a demonstrated track record of solid performance and proven reusability,” Eileen Drake, president and CEO of Aerojet Rocketdyne, said in a statement.

Now that Boeing has been selected by DARPA, the company is moving forward into Phase 2 and Phase 3 of the XS-1 program. Phase 2 includes the manufacture and testing of the vehicle’s technologies on the ground through 2019. In Phase 3, which is suppose to begin in 2020, the spaceplane will do 12 to 15 flight tests. A big objective of this phase is to fly the plane 10 times over a 10-day period, to demonstrate that the vehicle can do quick turnarounds. The first of these flights won’t include payloads, but the spaceplane will eventually test out sending payloads weighing 900 and 3,000 pounds into lower Earth orbit.

DARPA says the XS-1 will meet a critical need for the military by decreasing the amount of time it takes to get a satellite into orbit. That could be important if the US needs to get a satellite up in a pinch, perhaps if a crucial satellite in space is suddenly lost. But DARPA also hopes that the technologies created through the XS-1 program will eventually be adopted by the commercial spaceflight industry, to make getting satellites to space a potentially faster and cheaper endeavor.

“We’re delighted to see this truly futuristic capability coming closer to reality,” Brad Tousley, director of DARPA’s Tactical Technology Office (TTO), which oversees XS-1, said in a statement. “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.”