The Lockheed C-5 Galaxy is a large military transport aircraft originally designed and built by Lockheed, and now maintained and upgraded by its successor, Lockheed Martin. It provides the United States Air Force (USAF) with a heavy intercontinental-range strategic airlift capability, one that can carry outsize and oversize loads, including all air-certifiable cargo. The Galaxy has many similarities to its smaller Lockheed C-141 Starlifter predecessor, and the later Boeing C-17 Globemaster III. The C-5 is among the largest military aircraft in the world.
The C-5 Galaxy's development was complicated, including significant cost overruns, and Lockheed suffered significant financial difficulties. Shortly after entering service, cracks in the wings of many aircraft were discovered and the C-5 fleet was restricted in capability until corrective work was completed. The C-5M Super Galaxy is an upgraded version with new engines and modernized avionics designed to extend its service life beyond 2040.
The USAF has operated the C-5 since 1969. In that time, the airlifter supported US military operations in all major conflicts including Vietnam, Iraq, Yugoslavia and Afghanistan, as well as allied support, such as Israel during the Yom Kippur War and operations in the Gulf War. The Galaxy has also been used to distribute humanitarian aid and disaster relief, and supported the US Space Shuttle program.