LR89
The Rocketdyne LR89 was a liquid-fueled rocket engine developed in the 1950s by Rocketdyne, a division of North American Aviation. It was designed to serve as a booster engine the Atlas rocket family. The LR89 was a liquid oxygen (LOX) and RP-1 (kerosene) engine.
It was used in configurations where it worked alongside the LR105 sustainer engine to enhance thrust in the first stage of the Atlas, being jettisoned when the vehicle weight had been considerably reduced due to propellant consumption. It was used until the Atlas II, where the stage it was used on was replaced with the MA-5A, using two RS-56-OBA engines.
Description
The LR89 was part of a family of engines that Rocketdyne developed to power the first American ICBMs and satellite launch vehicles. It was a gas-generator cycle engine, in which a portion of the fuel and oxidizer is burned to drive a turbine, which powers the fuel pumps, and featured a hypergolic igniter.
Versions
The LR89 engine underwent several upgrades throughout its operational life, resulting in multiple versions:
| Version | Year | Thrust (kN) | Thrust (lbf) | Specific impulse (s) | Burn Time (s) | Stage |
|---|---|---|---|---|---|---|
| XLR89-1 | 1956 | 758.70 | 170,562.54 | 282 | 133 | MA-1 |
| XLR89-5 | 1958 | 758.70 | 170,562.54 | 282 | 135 | MA-2 |
| LR89-5 | 1960 | 822.50 | 184,905.35 | 290 | 120 | MA-3 |
| LR89-7 | 1963 | 948.00 | 213,118.87 | 294 | 259 | MA-5 |
Atlas stage
The LR89 powered the first Atlas stage, in different configurations:
- MA-1 (booster only): two XLR89-1 booster engines and two LR101 vernier engines. Used on Atlas A;
- MA-1: two XLR89-1 booster engines, an LR105-3 sustainer, and two LR101 vernier engines. Used on Atlas B and Atlas C missiles;
- MA-2: two XLR89-5 booster engines, an LR105-5 sustainer, and two LR101 vernier engines. Used on Atlas D and Atlas LV-3B;
- MA-3: two LR89-5 booster engines, an LR105-5 sustainer, and two LR101 vernier engines. Used on Atlas E, Atlas F and Atlas E/F;
- MA-5: two LR89-7 booster engines, an LR105-5 sustainer, and two LR101 vernier engines. Used on Atlas SLV3, Atlas H, Atlas LV3C, Atlas G and Atlas I.
See also
References
- ↑ "Rocket Engine Evolution". National Museum of the USAF.
- 1 2 3 "Technical Manual: Rocket Engine, USAF Model LR89-NA-5 (Rocketdyne)". National Air and Space Museum. Retrieved 2024-10-13.
- ↑ "LR-89 (Atlas Booster) Engine". heroicrelics.org. Retrieved 2024-10-13.
- ↑ Sutton, George P.; Biblarz, Oscar (2016). Rocket Propulsion Elements (9th ed.). John Wiley & Sons.
- 1 2 3 4 5 "Rocket Propulsion Evolution:5 - Atlas Missile". www.enginehistory.org. Retrieved 2024-10-13.
- ↑ "LR-89 (Atlas Booster) Rocket Engine Injector". heroicrelics.org. Retrieved 2024-10-13.
- ↑ Clark, Robert (2015-06-11). "The First Atlas Test Flights". Drew Ex Machina. Retrieved 2024-10-13.
- ↑ Walker, Chuck; Powell, Joel (2005). Atlas: The Ultimate Weapon. Apogee Books.
- 1 2 3 Wade, Mark (2019). "LR89-5". Encyclopedia Astronautica. Retrieved 2024-10-13.
- 1 2 Wade, Mark (2019). "XLR89-1". Encyclopedia Astronautica. Retrieved 2024-10-13.
- 1 2 Wade, Mark (2019). "XLR89-5". Encyclopedia Astronautica. Retrieved 2024-10-13.
- 1 2 Wade, Mark (2019). "LR89-7". Encyclopedia Astronautica. Retrieved 2024-10-13.
- ↑ Krebs, Gunter D. (2024). "Atlas Family". Gunter's Space Page. Retrieved 2024-10-13.
- ↑ "Atlas MA engine series". www.astronautix.com. Retrieved 2025-09-14.
- ↑ "Atlas A stage". www.astronautix.com. Retrieved 2025-09-14.
- ↑ "Atlas MA-2". www.astronautix.com. Retrieved 2025-09-14.
- ↑ "Atlas MA-3". www.astronautix.com. Retrieved 2025-09-14.
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