Radian Aerospace, a Seattle-based company, is developing a single stage to orbit spaceplane for missions to low earth orbit, including the International Space Station. The company just completed the initial ground taxi tests with its prototype flight vehicle, PFV01 in Abu Dhabi. The taxi tests included a series of pitch-up maneuvers and short hops, collecting critical data from integrated telemetry systems.
Single stage to orbit means that the new spacecraft would take off from a runway and fly directly to space. Plans are for the spaceplane to launch on top of a rocket sled that will rapidly accelerate down a runway to launch the airplane directly to low earth orbit.
The company’s Chief Technical Officer and co-founder, Livingston Holder, formerly worked with NASA on the X-33 spaceplane program. He indicated that technologies have improved since that program was cancelled in 2001, including lighter and thermally resistant composite materials and more efficient propulsion systems. By using a rocket sled on the ground for two miles, the spaceplane launches at a speed of 537 miles per hour and accelerates from there to go directly to low earth orbit. This gets them around a portion of the rocket equation and enables a single stage on the spaceplane to get it to orbit.
While heavy lift rockets will still be relied upon to lift heavy objects, this “pick-up truck” like space vehicle can be used to transport crews and smaller payloads to orbit. The technology is expected to be lower in cost to use, and a life of 1,000 flights is expected for the spaceplane, with a turnaround as quick as 48 hours to re-launch.
Full scale testing and first flights are expected in 2028. This will be a challenging engineering program to achieve, given the multiple obstacles associated with space flight. Nonetheless, leveraging new technology, this design has the potential for success and a unique market niche that is less expensive than vertical launch systems.
With the first ground tests of the prototype under way, the program is moving forward into initial testing. Given the improvements in technology in recent years, if those technologies can be successfully leveraged, a concept once thought infeasible could actually work. Stay tuned as we watch the development of a fascinating project that could compete with SpaceX and Boeing for ISS transportation.