Atlas V

Atlas V is an expendable launch system and the fifth major version in the Atlas launch vehicle family. It was developed by Lockheed Martin and has been operated by United Launch Alliance (ULA) since 2006. Primarily used to launch payloads for the United States Department of Defense, NASA, and commercial customers, Atlas V is the longest-serving active rocket in the United States. Each Atlas V vehicle consists of two main stages. The first stage is powered by a single Russian-made RD-180 engine that burns kerosene and liquid oxygen. The Centaur upper stage uses one or two American-made Aerojet Rocketdyne RL10 engines that burn liquid hydrogen and liquid oxygen. Strap-on solid rocket boosters (SRBs) are used in several configurations. Originally equipped with AJ-60A SRBs, the vehicle switched to Graphite-Epoxy Motor (GEM 63) boosters beginning in November 2020, except for flights in the Boeing Starliner program. Standard payload fairings measured either 4.2 m (14 ft) or 5.4 m (18 ft) in diameter, with multiple available lengths. In August 2021, ULA announced that Atlas V would be retired and all remaining launches had been sold. Production of the rocket ended in 2024. As of July 2026, six rockets remain, all of which are slated to launch Starliner missions. Future ULA launches will use the Vulcan Centaur rocket, which was designed in part to comply with a Congressional mandate to phase out use of the Russian-made RD-180 engine.