The Defense Advanced Research Projects Agency (DARPA) will work with The Boeing Company to develop an aircraft capable of flying at hypersonic speeds. Under the XS-1 program, DARPA and Boeing would design and build a reusable space plane that would use cryogenic propellants rather than external boosters.
At roughly the size of a commercial business jet, the space plane would be able to take off like a rocket and reach high suborbital altitude. It could carry a booster carrying a deployable 3,000-pound satellite payload, which it could deliver into polar orbit. Then, it could then return to Earth and be turned around for another flight within the matter of a couple of hours.
The technology to build the space plane currently exists. The propulsion unit that will be used in the XS-1 is a version of the Aerojet Rocketdyne AR-22 engine that powered the main engine of the Space Shuttle. The wings will be made of a hybrid of composite materials and metal, making it able to guide it through suborbital flight while withstanding temperatures that would exceed 2,000 degrees Fahrenheit. Missions and flight operations would be automated by incorporating numerous systems, including DARPA’s Airborne Launch Assist Space Access (ALASA) program.
Plans now call for designing, building and testing a demonstration craft, through 2019. During this phase, designers will try to fire its engine 10 times a day on the ground, to prove the system is flightworthy.
The team homes to conduct 12 to 15 flight tests by 2020, with the intent of flying the space plane 10 times during a 10-day period without payloads — at speeds as high as Mach 5. In future tests, they will try to take the space plane to speeds of Mach 10, and deliver a payload weighing between 900 and 3,000 pounds into low Earth orbit.
In years to come, space plane technology would be applied to commercial flights.