RD-180 test firing, November 4, 1998 at the Marshall Space Flight Center Advanced Engine Test Facility.
|Country of origin||Russia|
|Propellant||LOX / RP-1|
|Thrust (vac.)||933,400 lbf (4.15 MN)|
|Thrust (SL)||860,568 lbf (3.83 MN)|
|Chamber pressure||3,868 psia (26.7 MPa, 266.8 bar)|
|Isp (vac.)||338 s (3,313 N·s/kg)|
|Isp (SL)||311 s (3,053 N·s/kg)|
|Burn time||270 Sec|
|Length||140 in (3.56 m)|
|Diameter||124 in (3.15 m)|
|Dry weight||12,081 lb (5,480 kg)|
The RD-180 (РД-180, Ракетный Двигатель-180, Rocket Engine-180) is a Russian dual-combustion chamber, dual-nozzle rocket engine, derived from the RD-170 used in Soviet Zenit rockets, and currently provides first-stage power for the American Atlas V launch vehicle.
Design and specifications 
The combustion chambers of the RD-180 share a single turbopump unit, much like in its predecessor, the four-chambered RD-170. The RD-180 is fueled by a kerosene/liquid oxygen mixture and uses an extremely efficient, high-pressure staged combustion cycle. The engine runs with an oxidizer to fuel ratio of 2.72 and employs an oxygen-rich preburner, unlike typical fuel-rich US designs. The thermodynamics of the cycle allow an oxygen-rich preburner to give a greater power-to-weight ratio, but with the drawback that high pressure, high temperature gaseous oxygen must be transported throughout the engine. The movements of the engine nozzles are controlled by four hydraulic actuators. The engine can be throttled from 40% to 100% of rated thrust.
During the early 1990s General Dynamics Space Systems Division (later purchased by Lockheed Martin) acquired the rights to use the RD-180 in the Evolved Expendable Launch Vehicle (EELV) and the Atlas program. As these programs were conceived to support United States government launches as well as commercial launches, it was also arranged for the RD-180 to be co-produced by Pratt & Whitney. However all production to date has taken place in Russia. The engine is currently sold by a joint venture between the Russian developer and producer of the engine NPO Energomash and Pratt & Whitney, called RD AMROSS.
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.
Prospective uses 
Jerry Grey, a consultant to the American Institute of Aeronautics and Astronautics and Universities Space Research Association and a former professor of aerospace engineering at Princeton University, suggested using the RD-180 for a prospective NASA heavy-lift launch vehicle. For those who might be concerned about too much reliance on Russia, he pointed out that RD Amross was "very close to producing a U.S.-built version of the RD-180, and with some infusion of NASA funding could be manufacturing that engine (and perhaps even a 1,700,000 lbf or 7.6 MN thrust equivalent of the RD-170) in a few years."
Despite the availability of necessary documentation and legal rights for producing RD-180 in the United States, NASA is considering development of an indigenous core stage engine that would be "capable of generating high levels of thrust approximately equal to or exceeding the performance of the Russian-built engine." NASA intends to produce a fully operational engine by 2020, or sooner if it can establish a partnership with the U.S. Defense Department.
See also 
- Comparison of orbital rocket engines
- Staged combustion cycle used in engine
- RD-191 derivative engine being developed for the Angara rocket
- RD-0124 used in the Soyuz-2.1b
- RD-107 used in the R-7 Semyorka missiles and Soyuz FG
- RD-58 upper stage RP-1/LOX engine used in the N-1 rocket, derivatives used in the Proton and Zenit rockets
- RD-8 used in the Zenit rocket
- "Replacement for Soyuz rocket canned by Russia". Spaceflight Now. 2011-10-07. Retrieved 2011-10-08.
- Laying a Foundation for Human Space Exploration, by Jerry Grey
- NASA Propulsion Plans Resonate with Some in Rocket Industry. spacenews.com
- Pratt and Whitney official RD-180 page
- Astronautix.com page on RD-180
- RD-180 page (in Russian) at NPO Energomash
- RD-180 specifications and design (in Russian)