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The RD-170 is a bipropellant rocket engine and is the world's most powerful multi-nozzle, multi-chamber rocket engine that uses liquid propellants. Designed and produced by NPO Energomash, the RD-170 uses four combustion chambers which are supplied with propellants by a single turbo pump. The RD-170 burns the Russian equivalent of RP-1 fuel and LOX oxidizer in a staged combustion cycle. It was originally used with the Energia launch vehicle.

Several Soviet and Russian rocket engines use the approach of clustering small combustion chambers around a single turbine and pump. This results in a shorter but wider rocket motor which is somewhat easier to develop. During the early 1950s, many Soviet engine designers, including Glushko, faced problems of combustion instability, while designing bigger thrust chambers. At that time they solved the problem by using a cluster of smaller thrust chambers. Even if one thrust chamber fails, others can compensate by firing for a longer duration.

The RD-170 is now out of production, but it forms the basis for a family of modern rocket engines. One of these, the RD-171, is currently used in the Zenit rocket. While the RD-170 had nozzles which swiveled on only one axis, the RD-171 swivels on two axes. Models called the RD-172 and RD-173 were proposed upgrades providing additional thrust, but they were never built.

Another variant, the RD-180 used on the Atlas V, replaced the three engines used on early Atlas rockets with a single engine and achieved significant payload and performance gains. Another, the RD-191, is proposed for the Russian Angara rocket.

• 4 combustion chambers, 4 nozzles
• 1 set of turbines and pumps - Turbine produces approximately 257,000 hp (192 MW); equivalent to the power output of 3 nuclear powered icebreakers
• Ignition: Hypergolic
• Vacuum thrust of 1,773,000 lbf (7,887 kN)
• Vacuum Isp of 338 s (3,315 N·s/kg)
• Sea Level Isp of 309 s (3,030 N·s/kg)
• Weight: 9,750 kg (21,500 lb)
• Thrust to weight ratio: 82

• External image
• Astronautix.com entry on RD-170