Story updated: December 8, 2011 4:10 p.m.

Iran claimed December 4 to have shot down a Lockheed Martin RQ-170 Sentinel UAV along the country’s eastern border. Four days later, an almost intact airframe closely resembling the secret UAV was shown on Iranian television. The NATO International Security Assistance Force (ISAF) in Kabul admitted that operators of  “a U.S. unarmed reconnaissance UAV” had lost control of it during “a mission over western Afghanistan late last week”. The Fars News Agency in Tehran said the RQ-170 “had been downed with help from the Iranian military’s electronic warfare unit.”

Tehran claims to have shot down more than a dozen American UAVs that were spying on its military and nuclear facilities during the last few years, but has never previously produced the evidence. In the television footage, the UAV’s underside was masked by drapes, suggesting damage from a forced landing. The above-wing intake was seen to be covered by a radar-deflecting meshed grill, reminiscent of that covering the intakes of the F-117 Stealth Fighter - an earlier product of the Skunk Works. The commander of the Iranian Revolutionary Guards Corps Aerospace Forces told viewers that the wingspan of the UAV was 85 feet and the length 15 feet.

The RQ-170 is thought to have been developed by the Lockheed Martin Skunk Works by 2005-6. It was deployed to Kandahar by 2008. However, the U.S. Air Force did not officially acknowledge the program until December 2009, briefly describing the tail-less RQ-170 as a low-observable reconnaissance system to locate targets for the combatant commanders. AIN believes that the system is operated by the Skunk Works under contract. It has likely been used for covert missions over both Iran and Pakistan, including during the Osama bin Laden raid last May.

The Iranian reference to electronic warfare has led to speculation that the Sentinel’s command and control system was disrupted. The RQ-170 features two overwing fairings that may carry satcom antennas and/or signals intelligence sensors. The aircraft’s communications system should ideally include telemetry to inform operators on the ground of any malfunction during flight. The UAV is powered by a single jet engine of unknown origin.

The RQ-170 is thought to carry an imaging sensor behind the nosewheel bay. The main landing gears retract forward, suggesting that another small payload bay might be incorporated in the lower fuselage. This could accommodate a weapon or an electronic warfare system. The loss of the Sentinel’s technology would be embarrassing for the U.S., especially if the latest low-observable coatings have been applied to the airframe.