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RD-170 engine for Energia and Zenit rockets

Often referred to as the "most powerful rocket engine in the world," RD-170 was designed to propel the first stage of the super-heavy Energia rocket. As part of a reusable transportation system, RD-170 was designed to fire as many as 10 times. A similar engine designated RD-171 was intended for the first stage of the Zenit medium-lift rocket.

 


RD-170

Green structures are gimbal mechanisms designated 2D4100 and built at KB Arsenal in Leningrad (now St. Petersburg). They tilt combustion chambers steering the rocket along its flight trajectory.


The torturous development of the RD-170/171 series continued from 1976 to 1987, presenting some of the most serious challenges before engineers at Moscow-based NPO Energomash led at the time by Valentin Glushko. The first test firing of the engine took place on Aug. 25, 1980. Between 1981 and 1983, various problems plagued test firings. One of the botched tests at NPO Energomash test facility on the outskirts of Moscow reportedly ended with a massive explosion that sent a heavy metal cover of the troubled engine's turbopump several miles away concluding with an impact on the runway of Moscow's main international airport in Sheremetievo!

There were even proposals to replace troubled RD-170 with one-chamber NK engines from the first stage of the N-1 rocket.

However in the end, all problems were resolved and one of the engines made 18 full-length firings logging a total of 2,520 seconds on the test stand.

The engine was first used on the Zenit rocket in 1985 and then on Energia in 1987. On Dec. 5, 2013, NPO Energomash conducted 1000th firing of the RD-171M engine at the company's test bench, NIK-751. However at the beginning of 2019, NPO Energomash said that RD-171 engines had gone through a total of 900 tests with a total firing time exceeding 100,000 seconds (27.7 hours). According to the company, one copy of the engine performed more than 20 firings without its removal from the test bench.

Energomash also said that from 2006 and until June 30, 2016, RD-171 operated during 29 launches of the Zenit-3SL rocket. A number of completed engines had remained at NPO Energomash after the death of the Zenit launch vehicle, however they were not compatible with any other rocket and their subsequent fate was unclear, Head of NPO Energomash said in April 2021.

RD-171MV version (Insider Content)

In 2017, Director General of RKK Energia Vladimir Solntsev referred to a "simplified" and "cheaper" version of the RD-171 engine in connection with the Soyuz-5 (Sunkar) project.

 

Known specifications of the RD-170 family:

-
RD-170
RD-171
RD-171M
Development period
1976-1988
1976-1986
1992-1996, 2003-2004
Thrust on the Earth surface
740 tons
740 tons
740 tons
Thrust in vacuum
806 tons
806 tons
806 tons
Specific impulse on the Earth surface
309.2 seconds
309.2 seconds
309.2 seconds
Specific impulse in vacuum
337 seconds
337 seconds
337.2 seconds
Combustion chamber pressure
250 kilograms per square centimeter
250 kilograms per square centimeter
250 kilograms per square centimeter
Dry mass
9,750 kilograms
9,750 kilograms
9,300 kilograms
Fueled mass
10,750 kilograms
10,500 kilograms
10,300 kilograms
Diameter
3.8 meters
3.565 meters
3.565 meters
Length
4.0 meters
4.015 meters
4.015 meters
Number of firings
10
10
10
Fuel
Kerosene
Kerosene
Kerosene
Oxidizer
Liquid oxygen
Liquid oxygen
Liquid oxygen
Launch vehicle

 


Writing and photography by Anatoly Zak

Last update: February 3, 2022

All rights reserved

insider content

RD-170

RD-170 during assembly in 1980s.


RD-170

A scale model of the RD-170 engine. Copyright © 2001 Anatoly Zak


RD-171MV

A possible depiction of the RD-171MV engine.