The U-2 spy plane was first constructed at Lockheed Martin's Skunk Works in 1955 and went on to become one of the most important intelligence, surveillance, and reconnaissance (ISR) aircraft of the Cold War. It is one of the few aircraft of its vintage still in active service with the US Air Force, but Lockheed has now unveiled details of its possible successor. Designated the TR-X, the concept aircraft is an improved, stealthier version of the 60-year-old design and could enter service in 10 years.

With a wingspan of 103 ft (31 m) and a cruise speed of 475 mph (764 km/h), the U-2 carries a payload of 5,000 lb (2,268 kg) and can climb to its cruising altitude of over 70,000 ft (21,000 m) in a little over 45 minutes. According to Lockheed, at this altitude the spy plane can maintain surveillance over a wide area from a standoff position outside of hostile borders while providing longer line of sight data links.

The U-2 provided reconnaissance in almost every major international crisis involving the United States and was thrust into the public eye in 1960 when a CIA U-2A piloted by Gary Powers was shot down over the Soviet Union. It underwent a major redesign in the 1980s and its mission expanded to include work as a flying NASA observatory.

Despite an extremely successful career, the U-2 will reach the end of its service life in 2019. The Air Force isn't currently seeking a replacement, but Lockheed is anticipating the day when it does.

On September 14 at the Air Force Association's annual symposium, Lockheed displayed its vision of the Tactical Reconnaissance X (TR-X) concept aircraft. First announced in August to mark the 60th anniversary of the U-2 program, the TR-X retains many features of the U-2, such as a similar airframe, the same F118 GE 101 engine, and the same cruising altitude, payload, speed, and climb rate.

However, Lockheed says that the TR-X will be cheaper than the U-2 and offer a number of improvements. The U-2 has about as much stealth as a 1950s airplane, so the TR-X will have a smaller radar profile, as well as better survivability and open missions systems architecture. It will carry new sensors, support systems, and possibly laser weapons.

One key change is that the TR-X will be man optional. This is a feature that the Air Force is looking into because it's advantageous in missions that are too dangerous for a pilot.

The TR-X currently exists only as a proposal and a conceptual drawing, but Scott Winstead, Lockheed Martin's business manager for the U-2, said that it could enter service around 2025. Winstead says that the TR-X is also a potential replacement for the Northrop Grumman RQ-4 Global Hawk.