Lockheed Martin completed the process of upgrading the C-5A / B / C Galaxy strategic transport aircraft to the C-5M Super Galaxy standard. The last modernized C-5M Galaxy also completed the US Air Force / USAF's Reliability Enhancement and Re-engining Program (RERP).

The C-5M program, which started in 1998 and lasted for 20 years, has progressed in two phases. Within the first phase of the Avionics Modernization Program (AMP), the C-5s were fitted wit the more modern versions of avionics, then shifted to the RERP phase. In the RERP phase, the aircraft were completing the modernization process after replacing the old General Electric (GE) TF39-GE-1C turbofan engines with engines with the new GE CF6-80C2 commercial aircraft engines (Military desgination: F108-GE-100). With this modernization and engine replacement, the C-5M Galaxies had 22% higher engine performance, 20% longer range and 50% increased payload capacity than their predecessors. In addition, the reliability of aircraft engines has increased by 20%. The USAF chose to upgrade only the C-5M Galaxy aircraft with sufficient body lifetime.