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in use of a stretched, two-engine upper stage, and had a brief three-year operational career in 2002-2005 before being superseded by the Atlas V.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.

Manufacturer: Convair. Launches: 4. Success Rate: 100.00%. First Launch Date: 2002-02-21. Last Launch Date: 2005-02-03. Launch data is: continuing. LEO Payload: 10,718 kg (23,629 lb). Payload: 4,500 kg (9,900 lb). to a: Geosynchronous transfer trajectory. Apogee: 40,000 km (24,000 mi). Associated Spacecraft: HS 601, LM 700. Liftoff Thrust: 2,600.000 kN (584,500 lbf). Total Mass: 218,588 kg (481,904 lb). Core Diameter: 3.05 m (10.00 ft). Total Length: 52.80 m (173.20 ft). Launch Price $: 105.000 million. in: 2000 price dollars.

• Stage Number: 1. 1 x Stage: 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: Out of 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 Number: 2. 1 x Stage: 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 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: Out of 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.

2002 February 21 - 12:43 GMT - Launch Site: Cape Canaveral. Launch Complex: LC36. Launch Pad: SLC36B. Launch Vehicle: Atlas IIIB. Model: Atlas 3B. LV Configuration: Atlas 3B AC-204.

• Echostar 7 Nation: USA. Program: Echostar. Mass: 690 kg (1,520 lb). Class: Communications. Spacecraft: LM 700. Agency: Echostar. Manufacturer: Lockheed Martin Commercial Space. Perigee: 35,779 km (22,231 mi). Apogee: 35,794 km (22,241 mi). Inclination: 0.10 deg. Period: 1,436.10 min. COSPAR: 2002-006A. USAF Sat Cat: 27378. Direct Broasdcasting satellite. The first launch of the Atlas 3B, with the Common Centaur stretched two-engine upper stage. Launch delayed from December 19, 2001 and January 22. The Echostar 7 communications satellite was placed into geostationary transfer orbit. The first burn of the Centaur put the stack into a 185 x 193 km x 28.1 deg parking orbit. At 1305 UTC the Centaur burned again to achieve the final 245 x 57060 km x 22.6 deg transfer orbit and separated from Echostar. As of 2007 Mar 11 located at 118.92W drifting at 0.006W degrees per day.References: 4, 552, 554.

• AsiaSat 4 Nation: China. Payload: HS 601HP / AsiaSat 1R. Mass: 4,042 kg (8,911 lb). Class: Communications. Spacecraft: HS 601. Agency: AsiaSat. Manufacturer: Boeing Satellite Systems. Perigee: 35,772 km (22,227 mi). Apogee: 35,805 km (22,248 mi). Inclination: 0.00 deg. Period: 1,436.20 min. COSPAR: 2003-014A. USAF Sat Cat: 27718. Delayed from May 28, 2002, and January 13, February 5, and April 11, 2003. AsiaSat 4 was designed to provide broadcast, telecommunications and broadband multimedia services to the Asia Pacific region, and direct-to-home broadcast servic-es to Hong Kong, from its orbital position of 122 deg É East longitude.The satellite generated up to 9,600 watts using two sun-tracking four-panel solar wings covered with triple-junction gallium arsenide solar cells. AsiaSat 4 was to operate in C-band and Ku-band. The satellite carried 28 active transponders with six spares in C-band, powered by 55-watt traveling-wave tube amplifiers (TWTAs), and 20 active transponders with four spares in Ku-band, powered by 140-watt TWTAs. The C-band payload was designed to offer pan-Asian coverage, similar to AsiaSat 3S, also a 601HP model. The Ku-band payload provided high power, and spot beams for selected areas in either the Fixed Satellite Service frequency band or in the Broadcast Satellite Service frequency band. As of 2007 Mar 10 located at 122.23E drifting at 0.011W degrees per day.

• USA 174 Nation: USA. Program: UHF. Payload: UFO F/O F11. Class: Communications. Spacecraft: HS 601. Agency: USN. Perigee: 35,781 km (22,233 mi). Apogee: 35,798 km (22,243 mi). Inclination: 4.20 deg. Period: 1,436.20 min. COSPAR: 2003-057A. USAF Sat Cat: 28117. The last UHF Follow-On communications satellite for the US Navy. The satellite provided fleet communications from geostationary orbit.

• USA 181 Nation: USA. Class: SIGINT. Type: Naval reconnaisance. Spacecraft: NOSS-3. Perigee: 1,011 km (628 mi). Apogee: 1,209 km (751 mi). Inclination: 63.40 deg. COSPAR: 2005-004A. USAF Sat Cat: 28537. Last launch of an Atlas model using the original, innovative, balloon propellant tanks conceived in 1947. Third launch of new generation paired satellites used for tracking, characterisation, and intelligence on naval vessels and civilian shipping worldwide.

• USA 181 companion Nation: USA. Class: SIGINT. Type: Naval reconnaisance. Spacecraft: NOSS-3. Perigee: 1,011 km (628 mi). Apogee: 1,209 km (751 mi). Inclination: 63.40 deg. COSPAR: 2005-004C. USAF Sat Cat: 28541.

• McDowell, Jonathan, Jonathan's Space Home Page, Harvard University, 1997-present. Jonathan McDowell's complete on-line listing of all objects orbited and over 20,000 rocket launches Accessed at: http://www.planet4589.org/jsr.html.

• Lockheed Martin Coporation, Atlas Family Fact Sheets, September 1998.. Accessed at: http://www.lmco.com/ILS/txtmain/ils_lsysinfo.htm.