Since their debut in August 2002, Atlas V rocket launch vehicles have achieved 100 percent mission success in nearly 50 launches from Space Launch Complex-41 at Cape Canaveral Air Force Station, FL and Space Launch Complex-3E at Vandenberg Air Force Base, CA. This track record makes it the safest rocket launching from the USA, and an obvious choice to launch professional and private astronauts to space.
The Atlas V is modular in design, and when launching the CST-100 spacecraft will use the standard main engine and a Centaur upper stage.