Lockheed U-2 U-2S

The U-2Rs and former TR-1As, unified under the U-2R designation in 1992, began to be re-engined and modernised in 1994, with the first flight in the new configuration that October. The key change replaced the veteran J75 with the more efficient General Electric F118-GE-101 turbofan of 17,000 pounds thrust, alongside improved sensors and a GPS receiver. The result was named Senior Year and designated U-2S; 31 aircraft went through the conversion.

The U-2S can carry electro-optical and infrared imagery, synthetic aperture radar and signals intelligence payloads at the same time, and its open system architecture allows new sensors to be fielded quickly against emerging threats. Block 20 aircraft have glass cockpits, a digital autopilot, modernised electronic warfare systems and updated data links; the main sensors are the ASARS-2A radar, the SYERS-2C multispectral system and the ASIP signals intelligence payload. The legacy optical bar camera remained usable, although operations with it from Beale ended in 2022. The Avionics Technical Refresh upgrades, introduced in 2023, added open-architecture systems, better command and control networking and pilot workload management features.

The U-2 outlived its Mach 3 replacement, the SR-71, retired in 1998, and a long series of retirement plans: a budget document approved in December 2005 set its end no earlier than 2012, Donald Rumsfeld announced the retirement in January 2006 as a cost-cutting measure, and the RQ-4 Global Hawk was repeatedly offered as the successor. The counter-arguments were financial and operational: in 2014 the U-2 cost $2,380 per flight hour against the RQ-4’s $6,710, and that same year Lockheed Martin calculated the fleet had used only a fifth of its design service life. In 2020 the U-2 became the first military aircraft to integrate artificial intelligence in a mission, through the ARTUμ programme. In 2023 it was used to watch the Chinese balloon that crossed the United States and Canada, confirming that its payload carried signals intelligence antennas and large solar panels. Air Combat Command retired the first TU-2S and three U-2S in early 2024.