Encyclopedia Astronautica
Atlas IIIB



atlasv3.jpg
Atlas IIIA / Atlas I
Credit: © Mark Wade
American orbital launch vehicle. This was the first version of the Atlas to fly using Russian RD-180 engines; and the last version to fly using the original balloon-tank concept for the first stage. It differed from the Atlas IIIA in use of a stretched, two-engine upper stage, and had a brief three-year operational career in 2002-2005 before being superseded by the Atlas V.

The single-stage Atlas IIIB booster was the same as that used for the Atlas IIIA. The Lockheed-Martin manufactured Centaur upper stage was powered by two Pratt & Whitney RL10A-4-2 turbopump-fed engines burning liquid oxygen and liquid hydrogen. The changes to Centaur for the Atlas IIIB included a stretched tank (1.68 m) and the addition of the second engine. Guidance, tank pressurization, and propellant usage controls for both Atlas and Centaur phases were provided by the inertial navigation unit (INU) located on the forward equipment module.

In a typical Atlas IIIB launch, the vehicle's two RD-180 thrust chambers were ignited shortly before liftoff. Pre-programmed engine thrust settings were used during booster ascent to minimize vehicle loads by throttling back during peak transonic loads in the high dynamic pressure region, while otherwise maximizing vehicle performance. Just over two minutes into flight, as the vehicle reached an axial acceleration of 4 g's, the engines began to throttle back, eventually initiating a constant throttle rate to sustain acceleration at 5.5 g's. Booster engine cutoff occurred approximately three minutes into flight and was followed by separation of Centaur from Atlas.

The first Centaur burn lasted about five minutes, after which the Centaur and its payload coasted in a parking orbit. During the first burn, approximately eight seconds after ignition, the payload fairing was jettisoned. The second Centaur ignition occurred 27 minutes into the flight, continued for about three minutes, and was followed several minutes later by the separation of the spacecraft from Centaur. Major suppliers included: NPO Energomash / Pratt & Whitney - Atlas RD-180 engines; Pratt & Whitney - Centaur engines; Honeywell - Inertial Navigation Unit; BF Goodrich - Digital acquisition system; SAAB - Payload Separation Systems.

LEO Payload: 10,718 kg (23,629 lb). Payload: 4,500 kg (9,900 lb) to a GTO. Launch Price $: 105.000 million in 2000 dollars.

Stage Data - Atlas IIIB

  • Stage 1. 1 x Atlas IIIA. Gross Mass: 195,628 kg (431,285 lb). Empty Mass: 13,725 kg (30,258 lb). Thrust (vac): 4,148.722 kN (932,670 lbf). Isp: 337 sec. Burn time: 132 sec. Isp(sl): 311 sec. Diameter: 3.05 m (10.00 ft). Span: 3.05 m (10.00 ft). Length: 29.00 m (95.00 ft). Propellants: Lox/Kerosene. No Engines: 1. Engine: RD-180. Status: In production. Atlas booster and sustainer engine arrangement replaced by Glushko engines developed for Zenit. Not capable of single stage to single stage to orbit capability (an Internet spaceflight urban myth). The single-stage Atlas IIIA booster uses a high-performance RD-180 propulsion system produced by a U.S./Russian joint venture (RD AMROSS) comprised of Pratt & Whitney (U.S.) and NPO Energomash (Russia). The RD-180 burns liquid oxygen and RP-1 propellant and develops a lift-off (sea-level) thrust of 2.6 MN. The RD-180 throttles to various levels during atmospheric ascent to effectively manage the air-loads experienced by the vehicle enabling minimum Atlas vehicle and launch site infrastructure changes. Additionally, throttling results in satellite experienced flight environments that are nearly identical to Atlas IIAS.
  • Stage 2. 1 x Centaur IIIB. Gross Mass: 22,960 kg (50,610 lb). Empty Mass: 2,130 kg (4,690 lb). Thrust (vac): 198.319 kN (44,584 lbf). Isp: 451 sec. Burn time: 460 sec. Isp(sl): 0.0000 sec. Diameter: 3.05 m (10.00 ft). Span: 3.05 m (10.00 ft). Length: 11.68 m (38.32 ft). Propellants: Lox/LH2. No Engines: 2. Engine: RL-10A-4-2. Status: In production. Dual-engine Centaur for Atlas IIIB. The Lockheed Martin manufactured Centaur IIIB upper stage is powered by two Pratt & Whitney RL10A-4-2 turbopump-fed engines burning liquid oxygen and liquid hydrogen. The changes to Centaur for Atlas IIIB are a stretched tank (1.68 m) and the addition of the second engine. Guidance, tank pressurization, and propellant usage controls for both Atlas and Centaur phases are provided by the inertial navigation unit (INU) located on the forward equipment module. The first Centaur burn lasts about five minutes, after which the Centaur and its payload coast in a parking orbit. During the first burn, approximately eight seconds after ignition, the payload fairing is jettisoned. The second Centaur ignition occurs 27 minutes into the flight, continues for about three minutes, and is followed several minutes later by the separation of the spacecraft from Centaur.

AKA: Atlas 3B; Atlas IIRC; Atlas IIARC.
Status: Out of production.
Gross mass: 218,588 kg (481,904 lb).
Payload: 10,718 kg (23,629 lb).
Height: 52.80 m (173.20 ft).
Diameter: 3.05 m (10.00 ft).
Thrust: 2,600.00 kN (584,500 lbf).
Apogee: 40,000 km (24,000 mi).

More... - Chronology...


Associated Countries
Associated Spacecraft
  • HS 601 American communications satellite bus. First launch 1990.01.09. 3-axis unified ARC 22 N and one Marquardt 490 N bipropellant thrusters, Sun and Barnes Earth sensors and two 61 Nms 2-axis gimbaled momentum bias wheels. More...
  • LM 700 American communications satellite. 98 launches, 1997.05.05 (Iridium 8) to 2002.06.20 (Iridium SV98 ). The LM 700 had its first use in the Iridium system, a commercial communications network comprised of a minimum of 66 LEO spacecraft. More...

Associated Engines
  • RD-180 Glushko Lox/Kerosene rocket engine. 4152 kN. Atlas III, Atlas V stage 1. In production. Isp=337s. First flight 2000. Two-thrust-chamber derivative of the four-chamber RD-170 used on Zenit. More...
  • RL-10A-4-2 Pratt and Whitney lox/lh2 rocket engine. 99.1 kN. In production. Isp=451s. Used on Atlas IIIB launch vehicle. First flight 2002. Two engines; electro-mechanical thrust vector control actuators replaced earlier hydraulically actuated system. More...

See also
  • Atlas V The Atlas V launch vehicle system was a completely new design that succeeded the earlier Atlas series. Atlas V vehicles were based on the 3.8-m (12.5-ft) diameter Common Core Booster (CCB) powered by a single Russian RD-180 engine. These could be clustered together, and complemented by a Centaur upper stage, and up to five solid rocket boosters, to achieve a wide range of performance. More...

Associated Manufacturers and Agencies
  • Martin American manufacturer of rockets, spacecraft, and rocket engines. Martin Marietta Astronautics Group (1956), Denver, CO, USA. More...

Associated Stages
  • Atlas IIIA Lox/Kerosene propellant rocket stage. Loaded/empty mass 195,628/13,725 kg. Thrust 4,148.72 kN. Vacuum specific impulse 337 seconds. The American Atlas booster and sustainer engine arrangement was replaced by derivatives of Glushko engines developed for the Ukrainian Zenit launch vehicle. Not capable of single stage to single stage to orbit capability (an Internet spaceflight urban myth). More...
  • Centaur IIIB Lox/LH2 propellant rocket stage. Loaded/empty mass 22,960/2,130 kg. Thrust 198.32 kN. Vacuum specific impulse 451 seconds. Dual-engine Centaur for Atlas IIIB. The Lockheed Martin manufactured Centaur IIIB upper stage is powered by two Pratt & Whitney RL10A-4-2 turbopump-fed engines burning liquid oxygen and liquid hydrogen. The changes to Centaur for Atlas IIIB are a stretched tank (1.68 m) and the addition of the second engine. More...

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