It takes a lot more money and preparation to launch a rocket than to have a plane take off. That's why DARPA (the Defense Advanced Research Projects Agency) first initiated its Experimental Spaceplane (XS-1) program. The idea is that once built, the XS-1 could take off and land like a regular aircraft, but could also deliver satellite payloads into low-Earth orbit while airborne. Today, the agency announced its plans for Phase 1 of the program, which includes awarding contracts for designs of the autonomous spaceplane.

As outlined in a previous article, plans call for the unmanned XS-1 to be able to make 10 flights within 10 days, reaching a speed of Mach 10+ at least once, and launching payloads weighing between 3,000 and 5,000 pounds (1,361 to 2,268 kg) at under US$5 million a pop.

A second-stage rocket carrying each payload will fire once it's launched from the spaceplane at suborbital altitude, carrying the satellite to its final orbit. The XS-1 will proceed back to the ground, where it will land and immediately be prepared for its next launch.

In today's announcement, DARPA stated that it will be funding three companies to independently develop designs for an XS-1 demonstration vehicle. These include The Boeing Company (working with Blue Origin), Masten Space Systems (working with XCOR Aerospace), and Northrop Grumman Corporation (working with Virgin Galactic). The designs will be assessed based on criteria such as feasibility, performance, developmental and operational costs, and the potential for use in military, civil and commercial applications.

Boeing's take on the XS-1

Along with developing the demo vehicle designs, other goals of Phase 1 are to "Identify and conduct critical risk reduction of core component technologies and processes," and "Develop a technology maturation plan for fabrication and flight test of XS-1 system capabilities." The Phase 2 competition, planned to take place next year, will involve awarding a production order to build and demonstrate the spaceplane.

Virgin Galactic, Swiss Space Systems and Stratolaunch Systems are all working on similar concepts, in which satellites would be "flown into space."

The XS-1 concept is illustrated in the following video.

Sources: DARPA, Boeing