Atlantic Research has finished ground-testing the variable flow-ducted rocket (VFDR) solid-fuel ramjet engine for the GQM-13A supersonic sea-skimming target (SSST), which is under development by Orbital Sciences for the US Navy. Flight-testing of the Mach 2.5 target is scheduled to begin late next year, and will mark the first flight of a VFDR air-breathing rocket engine.
Source: Flight International