![Darpa](http://rack.1.mshcdn.com/media/ZgkyMDEzLzA5LzE5LzA3L2RhcnBhLmY4YWJmLmpwZwpwCXRodW1iCTU3NXgzMjMjCmUJanBn/b14d427a/21e/darpa.jpg)
The United States military is kick-starting a suborbital hypersonic vehicle program that also aims to launch payloads into orbit on the cheap.
The new program, run by the Defense Advanced Research Projects Agency, is called Experimental Spaceplane, or XS-1. It follows in the footsteps...