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'Atlas II' was a member of the Atlas family of launch vehicles, which evolved from the successful Atlas missile program of the 1950s. Atlas II was the last Atlas to use a three engine, "stage-and-a-half" design: two of its three engines were jettisoned during ascent, but its fuel tanks and other structural elements were retained. It was designed to launch payloads into low earth orbit, geosynchronous transfer orbit or geosynchronous orbit. Sixty-three launches of the Altas II, IIA and IIAS models were carried out between 1988 and 2004. (The larger Atlas III was used between 2000 and 2005, and the Atlas V is still in use.)

Contents

Features

Background

References

External links

Features

Atlas II provides higher performance than the earlier Atlas I by using engines with greater thrust and longer fuel tanks for both stages. The total thrust capability of the Atlas II of 490,000 pounds force (2,200 kN) enables the booster to lift payloads of 6,100 pounds (2,767 kg) in geosynchronous orbit of 22,000 miles (35,000 km) or more. This series uses an improved Centaur upper stage – the world’s first high-energy propellant stage – to increase its payload capability. Atlas II also has lower-cost electronics, an improved flight computer and longer propellant tanks than its predecessor, Atlas I.
The most powerful derivative is the Atlas IIAS.

Background

Atlas IIs are launched from Cape Canaveral Air Force Station, Fla., by the 45th Space Wing. The final West Coast Atlas II launch was accomplished December 2003 by the 30th Space Wing, Vandenberg AFB, Calif.
The Atlas was originally fielded as an ICBM in the late 1950s. On Oct. 31, 1959, the first Atlas, a D model stored horizontally, was placed on alert at Vandenberg AFB by the 576th Strategic Missile Squadron. Atlas E and F models were the first ICBMs to be stored vertically in underground silos and raised by elevators to an above-ground position for launch. The Air Force replaced the Atlas ICBMs with Titan ICBMs and converted the E and F models into space launch vehicles in the late 1960s. The last refurbished Atlas vehicle was launched from Vandenberg AFB in 1995 carrying a satellite for the Defense Meteorological Satellite Program.
NASA used the Atlas as a space launch vehicle as early as 1958. Atlas served as the launch vehicle for Project SCORE, an instrumentation package developed by the U.S. Army Signal Corps that became the world’s first communications satellite. The satellite broadcast President Eisenhower’s pre-recorded Christmas message around the world.
An Atlas booster carried astronaut John Glenn into orbit under Project Mercury, the first US manned space program. Atlas Centaur vehicles also launched Mariner and Pioneer planetary probes.
In May 1988, the Air Force chose General Dynamics (now Lockheed-Martin) to develop the Atlas II vehicle, primarily to launch Defense Satellite Communications System payloads and for commercial users as a result of Atlas I launch failures in the late 1980s.

★ General Characteristics

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★ Primary function: Launch vehicle

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★ Primary contractor: Lockheed Martin - airframe, assembly, avionics, test and systems integration

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★ Principal subcontractors: Rocketdyne (Atlas engine, MA-5); Pratt & Whitney (Centaur engine, RL-10) and Honeywell & Teledyne (avionics)

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★ Power Plant: Three MA-5A Rocketdyne engines, two Pratt & Whitney RL10A-4 Centaur engines

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★ Thrust: 494,500 lbf (2,200 kN)

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★ Length: Up to 156 ft (47.54 m); 16 ft (4.87 m) high engine cluster

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★ Core Diameter: 10 feet (3.04 m)

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★ Gross Liftoff Weight: 414,000 lb (204,300 kg)

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★ First Launch: February 10, 1992

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★ Models: II, IIA, and IIAS

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★ Launch Site: Cape Canaveral AFS, Florida

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★ Inventory: unavailable

References

★ USAF Atlas II Fact Sheet

External links

★ NASA page on Atlas IIAS Vehicle

★ Animation of the Atlas-IIAS launch and Terra satellite deployment