DARPA has awarded prime contracts for Phase 1 of its Experimental Spaceplane (XS-1) project. The agency’s vision is for a reusable spaceplane that will act as a “mothership” for expendable upper stages that will boost small satellites into orbit, allowing more routine, responsive and affordable space operations, according to a DARPA release. While the existing unmanned X-37B spaceplane can carry small satellites to orbit and is reusable, it still has to ride to orbit on an expensive booster that takes months to prepare for launch.

DARPA says that key technical goals for the XS-1 program are for the vehicle to be capable of flying 10 times in 10 days, flying to Mach 10+ at least once and launching a representative small payload to orbit. The program also seeks to reduce the cost of access to space for 3,000- to 5,000-pound payloads to less than $5 million per flight.

The XS-1 program aims to develop a fully-reusable unmanned vehicle that would provide aircraft-like access to space and deploy small satellites to orbit using expendable upper stages, the release states. Along with developing a technology to deploy small satellites faster and more affordably, the program will develop technology for next-generation hypersonic vehicles.

The three companies awarded Phase 1 contracts are:

• The Boeing Company (working with Blue Origin, LLC)
• Masten Space Systems (working with XCOR Aerospace)
• Northrop Grumman Corporation (working with Virgin Galactic)

“We chose performers who could prudently integrate existing and up-and-coming technologies and operations, while making XS-1 as reliable, easy-to-use and cost-effective as possible,” said Jess Sponable, DARPA program manager. “We’re eager to see how their initial designs envision making spaceflight commonplace – with all the potential military, civilian and commercial benefits that capability would provide.”

The XS-1 plan envisions a reusable mothership that would take off, fly to hypersonic speeds at a suborbital altitude, and then would deploy one or more expendable upper stages that would separate and boost a satellite into Low Earth Orbit (LEO). The mothership would then return to earth, land and be readied for the next flight. Modular components, durable thermal protection systems and automatic launch, flight and recovery systems should significantly reduce logistical needs, enabling rapid turnaround between flights, according to DARPA. The ability to boost satellites into LEO quickly and relatively cheaply has obvious commercial appeal, but there is also a vital military need for such a capability.

With the U.S. military so dependent on satellites of all types for everything from C4ISR to navigation to remotely piloted vehicles to missile defense, potential adversaries are expanding their capabilities to shoot them down. Being able to quickly launch satellites to replace those downed or disabled space assets would be a key capability.

DARPA says that key technical goals for the XS-1 program are for the vehicle to be capable of flying 10 times in 10 days, flying to Mach 10+ at least once and launching a representative small payload to orbit. The program also seeks to reduce the cost of access to space for 3,000- to 5,000-pound payloads to less than $5 million per flight.

Phase 1 of XS-1 is intended to evaluate the technical feasibility and methods for achieving the program’s goals. Tasks currently include:

1. Develop the XS-1 demonstration vehicle
2. Identify and conduct critical risk reduction of core component technologies and processes
3. Develop a technology maturation plan for fabrication and flight test of XS-1 system capabilities