By Cliff Lethbridge

Atlas IIIB-Centaur Launch, Photo Courtesy Lockheed-Martin

Atlas IIIB-Centaur Launch, Photo Courtesy Lockheed-Martin

Classification: Space Launch Vehicle

Length: 173 feet

Diameter: 10 feet

Date of First Cape Canaveral Launch: February 21, 2002

Date of Final Cape Canaveral Launch: February 3, 2005

Number of Cape Canaveral Launches: 4

Otherwise identical to the Atlas IIIA, the Atlas IIIB improved performance by employing a two-engine Centaur upper stage, as opposed to a one-engine Centaur upper stage employed on the Atlas IIIA. The two-engine Centaur, featuring two RL-10A engines, could produce a thrust of 41,592 pounds, roughly double the thrust of a single RL-10A engine. In the new configuration, the Atlas IIIB was capable of carrying a 23,630-pound payload to Low-Earth Orbit or a 9,900-pound payload to Geosynchronous Transfer Orbit.