Atlas 3B vehicle data
Posted: April 9, 2003
The Atlas 3B is a two-stage rocket capable to lifting payloads of 4,500 kg (9,920 lb) into a geostationary transfer orbit. It features no strap-on solid rocket boosters.
Atlas is the name of a family of booster stages. Centaur is a family of high-energy, restartable upper stages. Atlas 3 is the designation for an Atlas 3 stage with a booster engine and a Centaur 3 upper stage. The Atlas 3B uses a "stretched" Centaur.
Atlas booster propulsion is provided by the RD AMROSS RD-180 engine system, which consists of two thrust chambers fed by a common turbopump assembly. The engine is ignited before liftoff and develops a total sea-level-rated thrust of 617,500 pounds. The interstage adapter connects the Atlas to the Centaur. This aluminum structure provides the structural link between Atlas and Centaur. The Atlas is separated from the Centaur by a flexible linear-shaped charge system attached to the forward ring of the interstage adapter.
Centaur Upper Stage
Centaur avionics packages, mounted on the equipment module, control and monitor all vehicle functions. Centaur avionics perform the inertial guidance and attitude control computations for both Atlas and Centaur phases of flight, and control Centaur tank pressures and propellant use.
The Centaur propulsion system uses one RL10A-4-1B engine with an extendible nozzle manufactured by Pratt & Whitney. The Centaur engine is restartable and is capable of multiple firings in space, separated by coast phases.
The stub adapter and equipment module are attached to the forward end of the Centaur. The stub adapter is bolted to the forward ring of the Centaur tank and supports the equipment module and payload fairing. The equipment module attaches to the forward ring of the stub adapter and provides for mounting of the Centaur avionics and the spacecraft adapter.
The payload fairing is a two-half-shell structure constructed of aluminum with vertical, split-line longerons. It consists of a cylindrical section topped by a conical nose cone and a spherical cap.
The fairing provides thermal and acoustic enclosures for the payload and launch vehicle electronic compartments during prelaunch and ascent. Portions of the external surface of the fairing are insulated with cork to limit temperatures to acceptable levels. Noncontaminating thermal control coatings are used on internal surfaces to reduce incident heat fluxes to the spacecraft. The payload fairing is jettisoned after Centaur Main Engine Start 1.
While coasting in the transfer orbit, the Centaur issues separation commands to release and separate the spacecraft from the forward adapter.
MISSION STATUS CENTER