RD-180 (rocket engine)
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The RD-180 is a dual-combustion chamber, dual nozzle, Russian-developed rocket engine which is essentially a cut-down version of a larger Russian engine with four combustion chambers, the RD-170, which is used in Zenit rockets. Rights to employ the RD-180 engine were acquired by General Dynamics (later purchased by Lockheed Martin ) in the early 1990s for use in the Evolved Expendable Launch Vehicle (EELV) and the Atlas program. As these programs were conceived to support US government launches as well as commercial launches, it was arranged for the RD-180 to be co-produced by Pratt & Whitney. All production to date has been in Russia. The engine is currently sold by a joint venture between Pratt & Whitney and NPO Energomash (the Russian developer and builder) called RD AMROSS.
The RD-180 is fueled by a kerosene / LOX mixture and uses an extremely efficient, high-pressure staged combustion cycle. The engine (and its progenitor the RD-170) is unique in that it employs a LOX-rich preburner, unlike typical fuel rich US designs. The thermodynamics of the cycle allow a LOX-rich preburner to be more powerful per unit weight, but with the drawback that high pressure, high temperature gaseous Oxygen must be transported throughout the engine. The movements of its nozzles are controlled by four hydraulic actuators. It is a very large engine and extremely sturdily built.
The RD-180 was first deployed on the Atlas IIA-R vehicle, which was the Atlas IIA vehicle with the Russian (hence the R) engine replacing the previous main engine. This vehicle was later renamed the Atlas III. An additional development program was undertaken to certify the engine for use on the modular Common Core Booster primary stage of the Atlas V rocket.
As an additional note, the RD-180 engine which was initially used for structural tank testing at the Lockheed Martin Astronautics main plant in Denver was also displayed at a G8 Summit meeting at which US President Clinton and the Russian president Boris Yeltsin met.
[edit] Specifications
- Thrust (vac): 933,400 lbf (4.15 MN)
- Isp (vac): 338 sec (3,313 N·s/kg)
- Isp (sea level): 311 sec (3,053 N·s/kg)
- Mass: 12,081 lb (5,480 kg)
- Diameter: 124 in (3.15 m)
- Length: 140 in (3.56 m)
- Chambers: 2
- Chamber pressure: 257 bar / 3,722 psia (25.7 MPa)
- Area ratio: 36.87
- Oxidizer to fuel ratio: 2.72
- Thrust to Weight ratio: 78.44
