Atlas III launch vehicle family

Atlas III was Lockheed Martin's transitional Atlas-Centaur generation. It replaced the classic booster-and-sustainer propulsion package with one Russian-built RD-180 while retaining pressure-stabilized Atlas propellant tanks. Two IIIA and four IIIB vehicles completed six successful missions from 2000 through 2005, introducing the RD-180 and stretched Centaur architecture carried into Atlas V.