AR-22
DARPA, companies declare success in AR-22 engine test series
A government-industry team announced July 10 they successfully completed a series of 10 test firings over 10 days of a shuttle-era engine intended for use on a reusable suborbital spaceplane.
Engine tests underway for DARPA spaceplane program
A space shuttle-era main engine is undergoing a series of daily test firings to demonstrate its suitability for use on a reusable spaceplane under development.
