science

RD-170

RD-170 is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand RD-170 rather than just read about it. In short: The RD-170 (Russian: Ракетный Двигатель-170 (РД-170), romanized: Raketnyy Dvigatel-170, lit. 'Rocket Engine-170') is the world's most powerful and heaviest liquid-fuel rocket engine. It was designed and produced in the Soviet Union by NPO Energomash for use with the Energia launch vehicle.

Key takeaways

RD-170 belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect RD-170 to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of RD-170 from memory before moving on to harder problems.

Reference excerpt

The RD-170 (Russian: Ракетный Двигатель-170 (РД-170), romanized: Raketnyy Dvigatel-170, lit. 'Rocket Engine-170') is the world's most powerful and heaviest liquid-fuel rocket engine. It was designed and produced in the Soviet Union by NPO Energomash for use with the Energia launch vehicle. The engine burns RG-1 fuel and LOX oxidizer in four combustion chambers, all supplied by one single-shaft, single-turbine turbopump rated at 170 MW (230,000 hp) in an oxidizer-rich stage combustion cycle.

Shared turbopump Several Soviet and Russian rocket engines use the approach of clustering small combustion chambers around a single turbine and pump. During the early 1950s, many Soviet engine designers, including Valentin P. 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.

Variants

RD-170 The RD-170 engine featured four combustion chambers and was developed for use on the Energia launch vehicle – both the engine and the launch vehicle were in production only for a short time. Energia was launched twice. Each Energia vehicle had 4 boosters, each powered by one RD-170. The engine was designed to be reused up to 10 times, with a total service life of 20 full burn durations.

RD-171

Building on the technology from the Energia's liquid fuel booster the Zenit was developed, which uses a RD-170 variant, the RD-171. While the RD-170 had nozzles which swiveled on two axes, the RD-171's nozzles only swivel on one axis. Models called the RD-172 and RD-173 were proposed, upgrades that would provide additional thrust, and the RD-173 proposal was finalized as the RD-171M upgrade in 2006.

RD-171MV A modification of RD-171M used on the Irtysh rocket. Unlike RD-171M it only uses Russian components and features a new control system. First test sample was manufactured in early 2019. Tests were reported to have been successfully completed in September 2021. The engine first launched in April 2026, with the first launch of the Soyuz 5 rocket.

Dual-chamber derivative

The RD-180 uses only two combustion chambers instead of the four of the RD-170. 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. This engine had also been chosen to be the main propulsion system for the first stage of the now cancelled Russian Rus-M rocket.

Single-chamber derivative

The RD-191 is a single-chamber version used in the Russian Angara rocket. Variants of RD-191 include RD-151 in South Korean Naro-1 rocket, RD-181 in American Orbital ATK Antares rocket, and the proposed RD-193 for the Soyuz-2-1v project.

Proposed variants On 28 July 2011, NPO Energomash summarised the results of the work on Rus-M rocket engine and considered the possibility of construction several new variants of RD-170 family engines. According to the information, new and proposed variants will be marked as:

RD-180M for crewed Atlas V rocket (Not required, current RD-180 meets crewed Atlas V requirements.) RD-180V for Rus-M rocket. RD-175 with 9800 kN thrust for proposed Energia-K rocket. 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.

Specifications 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: pyrophoric start-up fuel capsule (triethylaluminium) Vacuum thrust: 7,887 kN (1,773,000 lbf) Vacuum Isp: 338 s (3.31 km/s) Sea-level Isp: 309 s (3.03 km/s) Weight: 9,750 kilograms (21,500 lb) Thrust-to-weight ratio: 82

See also Comparison of orbital rocket engines

References

External links Manufacturer's Page (Archived) RD-170/171 specifications and design (in Russian) External image Astronautix.com entry on RD-170

Illustrations

Worked examples

Example 1 — a first encounter with RD-170

Start with the simplest possible case. Write down what RD-170 claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to RD-170 before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about RD-170 ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of RD-170

In research: RD-170 appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses RD-170 in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: RD-170 is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1980s rocket engines, Energomash rocket engines, Rocket engines of Russia, so understanding it makes those chapters shorter.
In everyday life: Look for RD-170 outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study RD-170 in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what RD-170 means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain RD-170 out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is RD-170 in simple terms?

Why does RD-170 matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study RD-170?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on RD-170.