Launch of an Atlas II rocket |
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| Function | Medium expendable Launch vehicle |
|---|---|
| Manufacturer | Lockheed Martin |
| Country of origin | United States |
| Size | |
| Height | 47.54 m (156 ft) |
| Diameter | 3.04 m (10 ft) |
| Mass | 204,300 kg (414,000 lb) |
| Stages | 3.5 |
| Capacity | |
| Payload to LEO | 6,580 kg |
| Payload to GTO |
2,810 kg |
| Associated rockets | |
| Family | Atlas |
| Launch history | |
| Status | Retired |
| Launch sites | SLC-36, Cape Canaveral SLC-3 Vandenberg AFB |
| Total launches | 63 (II: 10, IIA: 23, IIAS: 20) |
| Successes | 63 (II: 10, IIA: 23, IIAS: 20) |
| Maiden flight | II: 7 December 1991 IIA: 10 June 1992 IIAS: 16 December 1993 |
| Last flight | II: 16 March 1998 IIA: 5 December 2002 IIAS: 31 August 2004 |
| Notable payloads | SOHO (Atlas IIAS) TDRS (Atlas IIA) |
| Boosters (Atlas IIAS) - Castor 4A | |
| No. boosters | 4 |
| Engines | 1 Solid |
| Thrust | 478.3 kN (107,530 lbf) |
| Specific impulse | 266 sec |
| Burn time | 56 seconds |
| Fuel | Solid |
| Boosters (all) - MA-5 | |
| No boosters | 1 |
| Engines | 2 RS-58-OBA |
| Thrust | 2,093.3 kN (470,680 lbf) |
| Specific impulse | 299 sec |
| Burn time | 172 seconds |
| Fuel | LOX/RP-1 |
| First stage | |
| Engines | 1 RS-58-OSA |
| Thrust | 386 kN (86,844 lbf) |
| Specific impulse | 316 sec |
| Burn time | 283 seconds |
| Fuel | RP-1/LOX |
| Second stage - Centaur | |
| Engines | 2 RL-10A |
| Thrust | 147 kN (41,592 lbf) |
| Specific impulse | 449 sec |
| Burn time | 392 seconds |
| Fuel | LH2/LOX |
| Third stage - IABS (optional) | |
| Engines | 1 R-4D |
| Thrust | 980N (220 lbf) |
| Specific impulse | 312 sec |
| Burn time | 60 seconds |
| Fuel | N2O4/MMH |
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 Atlas II, IIA and IIAS models were carried out between 1991 and 2004. (The larger Atlas III was used between 2000 and 2005, and the Atlas V is still in use.)
Contents |
Atlas II provided 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) enabled the booster to lift payloads of 6,100 pounds (2,767 kg) into geosynchronous orbit of 22,000 miles (35,000 km) or more. This series used an improved Centaur upper stage – the world’s first high-energy propellant stage – to increase its payload capability. Atlas II also had lower-cost electronics, an improved flight computer and longer propellant tanks than its predecessor, Atlas I.
The most powerful derivative was the Atlas IIAS.
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. Led by lead engineer Samuel Wagner, the Atlas II was crucial to the continued development of the United States' space program.
Atlas IIs were 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.
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