Northrop Grumman Developing XS-1 Experimental Spaceplane Design for DARPA
"Northrop Grumman Corporation (NOC) with Scaled Composites and Virgin Galactic is developing a preliminary design and flight demonstration plan for the Defense Advanced Research Projects Agency's (DARPA) Experimental Spaceplane XS-1 program.
XS-1 has a reusable booster that when coupled with an expendable upper stage provides affordable, available and responsive space lift for 3,000-pound class spacecraft into low Earth orbit. Reusable boosters with aircraft-like operations provide a breakthrough in space lift costs for this payload class, enabling new generations of lower cost, innovative and more resilient spacecraft."