- Family: Atlas
- Length: 59.7 m
- Diameter: 3.8 m
- Launch Mass: 573 T
- Low Earth Orbit Capacity: 18850 kg
The Atlas V 551 was manufactured by United Launch Alliance with the first launch on 2006-01-19. Atlas V 551 has 13 successful launches and 0 failed launches with a total of 13 launches. Atlas V is an expendable launch system in the Atlas rocket family. It was formerly operated by Lockheed Martin and is now operated by United Launch Alliance (ULA), a joint venture with Boeing. Each Atlas V rocket uses a Russian-built RD-180 engine burning kerosene and liquid oxygen to power its first stage and an American-built RL10 engine burning liquid hydrogen and liquid oxygen to power its Centaur upper stage. The RD-180 engines are provided by RD Amross, while Aerojet Rocketdyne provides both the RL10 engines and the strap-on boosters used in some configurations. The standard payload fairing sizes are 4 or 5 meters in diameter and of various lengths. Fairings sizes as large as 7.2 m in diameter and up to 32.3 m in length have been considered. The rocket is assembled in Decatur, Alabama and Harlingen, Texas.