The X-47B is a larger variant of the X-47A. DARPA was awarded the contract to Northrop Grumman for three X-47B demonstrator UCAVs and an operational assessment phase to last from 2007-09. In addition to developing the air vehicle and the vehicle's autonomous control systems, the contract also covers the development of a UCAV mission control system. The vehicles will demonstrate the feasibility of meeting navy and air force UCAV performance requirements The performance parameters include the capability of sustaining a 2-hour loiter time at a target distance of 1,850km, and also a combat mission radius of 2,400km (1,000nm) with a mission payload of 2,040kg.

The vehicle is robustly built for carrier take-off and landings and uses a conventional wheeled take-off and landing with an arrestor hook. The retractable tricycle type landing gear consists of a single nose wheel, twin wheel main landing gear and a fully retractable arrestor hook.