Lockheed Martin’s Skunk Works (Advanced Development Programs) developed the RQ-170 Sentinel as a stealth UAV used for reconnaissance. The RQ-170 Sentinel’s design bears some resemblance to Lockheed Martin’s previous stealth and UAV programs such as the RQ-3 DarkStar and P-175 Polecat. The tail-less flying wing aircraft houses pods on its upper sufferance, which apparently carry sensors or a satellite communications system. Few details of the RQ-170 Sentinel’s structural specifications have been disclosed, although estimates of its wingspan range from approximately 65 feet (20 m) to 90 feet (27 m). Aviation Week estimates that the RQ-170 Sentinel, with its single engine design, to weigh more than the 8,500 pound RQ-3 DarkStar. Aviation Week also suggests that the medium-grey color implies a mid-altitude ceiling, unlikely to exceed 50,000 feet since a higher ceiling would normally be painted darker. Weight and ceiling characteristics suggest the RQ-170 Sentinel possibly uses a General Electric TF34 engine or a variant for propulsion.
The “RQ” letters in the name of the RQ-170 Sentinel indicate that it does not carry weapons. Aviation Week’s David A. Fulghum believes that the RQ-170 Sentinel is probably a “tactical, operations-oriented platform and not a strategic intelligence-gathering design.” If so, the RQ-170 Sentinel would be used to assist in providing information for military strikes rather than carry them out itself. The RQ-170 Sentinel could conceivably be used in conjunction with armed UAV drones, such as the MQ-1 Predator or MQ-9 Reaper.
Following a discussion of the RQ-170 Sentinel on December 4, 2009, the United States Air Force (USAF) confirmed the “grainy photos of a gray, flying-wing-typed unmanned airplane near Kandahar Airfield.” A USAF colonel said that RQ-170 is separate from the MQ-X program, which has yet to determine stealth or powerplant requirements, and thus the RQ-170 Sentinel will not replace the MQ-1 Predator and MQ-9 Reaper drones currently in service.