The Excellent Engineering Of SpaceX Raptor Engines

29 SpaceX Raptor Engines

The Starship is nothing without its SpaceX Raptor engines. They produce the thrust to help the Starships escape the Earth’s gravitational pole and propel it on its interplanetary journeys.

SpaceX Raptor Engines Closeups
SpaceX Raptor Engines

The thrust they produce has to be enormous as the Starship is meant to lift heavy payloads of up to 100 tons. This is important if Musk’s dream of planting people on Mars is to materialize. All the stuff necessary for life will be transported to the planet by the Starships and SpaceX is not short of powerful rockets.

Part of its roster of spacecraft is the Falcon 9, which is partially reusable. It is capable of blasting payloads up to 22,800 kilograms to low earth orbit. Falcon 9 is powered by the Merlin engine developed in-house by SpaceX.


SpaceX is introducing lots of insane concepts that few rocket companies have tried. The result is a beast masquerading as a rocket engine. Each Raptor engine weighs about 1.5 tons and will supply 11 million horsepower to the Starships, the equivalent of four Hoover dams.

By comparison, the Bugatti Veyron one of the most powerful sports cars ever made has an engine that weighs one-third but can not produce more than 1200 horsepower. The exhaust of the Raptor engine is expelled at over 10 times the speed of sound. If that is not crazy enough for you, the fuel and the chamber burn at temperatures high enough to melt the Chamber’s walls.

SpaceX Raptor Chamber's Wall
SpaceX Raptor Chamber’s Wall

If you wonder why the wall does not melt that’s because of the clever way the flame is kept away from the walls or manipulating the flow of the gas super-cold fuel is also pumped through the walls as additional security. The Raptor engine works like most rockets do expelling gases, fast enough to push the spacecraft forward.

However, a lot of clever engineering makes the Raptor a mighty rocket. The engines depart, and they’re designed from standard fare for rockets as SpaceX opted for a full-flow staged combustion cycle. Inside engine ignition is handled by the dual redundant spark plug-lit torch Igniters, which means there is no need for a dedicated, consumable igniter fluid as found in the Merlin. The raptor combines methane and oxygen that is deeply cooled for propellants near their freezing point at such low temperatures. The propellant is denser, which increases the overall performance of the engine.


Methane is a better fuel because of its higher performance and lower costs than kerosene or hydrogen-based propellants. It is far easier to store than hydrogen as it requires less effort to keep it cool at cryogenic levels. It also weighs less than hydrogen. Meaning more methane can be stored in the same tank.

Methane is better than kerosene as the latter forms residue during burning known as coking limiting the rocket’s reusability. The higher efficiency means that with almost the same size as the Merlin engine, the Raptor engine produces far higher pressure and thrust. There is simply no other rocket engine in existence, capable of producing as much energy using liquid methane and oxygen as a propellant.

Starship is heading to Mars and guesses which gas is abundant there? Methane, so the idea is to mind the methane on the planet. So Starships can refuel before embarking on the return trip. This will simplify lots of things and even make the trips cheaper by a high magnitude. It will be similar to your airplane landing at a foreign airport and refueling for another takeoff.

The full-flow staged combustion cycle means both the oxygen and the methane will be mixed entirely in the gas phase before entering the combustion chamber. This way, every drop of fuel is used efficiently. The full flow design makes a lot of sense for several reasons. For example, it eliminates the need for a ceiling between the fuel and the oxidizer. This ceiling is often a source of failure in traditional rockets using a full flow design also means the pumping system does not need to handle extreme pressure, which is another possible source of catastrophic failure. In addition, SpaceX can dial up the pressure in the combustion chamber to seek out more performance.


In fact, during testing, the Raptor has achieved 330 bar of pressure without exploding. Setting a record for an operational engine to be used for orbital payloads. All these contribute to the high reusability of the Raptor engines. They are actually suitable for 1000 flights, which is a big deal in space travel.

List Of Rockets Engine
List Of Rockets Engine (Source: Everyday Astronaut)

When compared with rockets from other companies, the Raptor engine is miles ahead. It crushes other rockets in efficiency and safety. SpaceX was initially 3d printing the components in the engine, including the turbopumps and injectors, allowing them to advance the development and testing at a fast clip.


Sea Level Raptor And Vacuum Raptor Engine
Sea Level Raptor (Left) And Vacuum Raptor Engine

There are two variants of the Raptor engine. The Sea-level variant will power the lower stage of the Starships and has been optimized for working on earth. The other variant, the Vacuum version will keep the upper stage moving after being disconnected from the booster. To optimize for performance in space, the vacuum version has a nozzle skirt extension making it bigger.

The differences can be easily noticed when the two are placed side-by-side in other specifications and components. The two variants are identical. The high-performance Raptors are not exactly cheap. Initially, each engine costs SpaceX a million dollars to build, but SpaceX is working on cutting it down to $250,000 of pop.


The cost is significant to Musk as he tries to make interplanetary trips affordable to everybody. This is why the Raptor engine is designed to require as minor refurbishment as possible for multiple uses. His company is working to ramp up production and be able to make the rocket engines in mass. The immediate goal is to make 500 of them per year.

However, if Musk’s plan is to have a fleet of a thousand Starships, making thousands of flights is to occur. That capacity will need to be increased significantly. A single Starships can use up to 41 Raptor engines. The lower stage may require 31 C-level variants. Although the actual number has varied during the testing of the Starships.

 SpaceX Starship Upper Stage With Six Raptors
SpaceX Starship Upper Stage With Six Raptors

The upper stage will take six Raptors, a mixture of both the level and vacuum variants. The Sea-level engines are needed for landing both on earth and on Mars while SpaceX races to finish the Raptor engines, lots of people are monitoring the progress.


NASA, for example, has tapped the Starships to help land its astronauts on the moon. As it revitalizes its space exploration program with project Artemis, it is working on a 2024 deadline. Beyond the moon, the Raptor engine is insanely essential to NASA as it hopes to use the Starships, to get astronauts to Mars in the long run. Trips to even more distant planets like Jupiter are also on the cards.

This is why it agreed to give $2.9 billion to SpaceX to fund the spacecraft development. Another big name waiting on the Raptor engine is the US military after getting a taste of the goodness of SpaceX rockets that launched its national security satellites. The number one force on earth is planning to use the Starships for rapid delivery of both cargo and personnel to places on earth with the powerful Raptor rocket engines. SpaceX is building a revolutionary engine that produces an insane amount of thrust and will power the spacecraft of the future.

You can check SpaceX Upcoming Launch here.

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4 months ago


4 months ago

I love these raptors

4 months ago

Pretty sure Methane isn’t lighter than Hydrogen (the lightest element that exists), nor does it provide better performance. The other points are valid.

4 months ago

This thing is a work of art and it’s components can be 3D printed? He just might reach his goal of 1,000 rockets if that’s the case.

4 months ago

Mistake in the article. You claim Mars atmosphere contains abundant methane. It does not. However it does contain abundant raw materials to use a process called The Sabatier Process to produce methane.

Truong Nguyen
4 months ago

Pretty sure the Rd 180 had a chamber pressure of something like 270 or 280 bar not 31 😀

4 months ago

When will SpaceX transition away from Fossil Fuels?

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