Raptor

The Raptor reusable engine has been under development since 2013, A full flow, gas-gas, staged combustion design.

Currently (Jan 2022) SpaceX is working hard to mass produce it latest upgraded Raptor 2.0 engines, designed to  work at a record breaking 300+ bar, a recent test engine worked at a chamber pressure of 321 bar (~4650 psi) and briefly produced around 245 tons of thrust. Raptor 2.0 engines are rated for 230 tons of thrust.

The  Raptor 2.0 engines will gave Starship over 10% more capability.

As of May 2023, The new Raptor 3.0 reusable engines are now rated at an amazing 350 BAR and have 269 tons of thrust. 

 Sea Level  and Vacuum Raptor's

NOTE: A Radically redesigned Raptor fired in January 2019

Elon: Raptor turbopumps alone need 100,000 horsepower per engine.

Three Raptor Engines in April 2020 at Boca Chica, Texas waiting to be installed in the SN4 or SN5  Starship test prototype.

Raptor engine on Starhopper's flight test debut 25th July 2019

SpaceX Starhopper Drone cam - Starship Prototype - first successful hop attempt, 25-7-2019

In May 2019 first 4 production Raptor engines had been tested and  Elon said production is being ramped up at Hawthorn and should see the first 100 Raptors produced by early next year. enough engines for at least two full StarShip and Super Heavies this year + test engines for the Starship ORBITAL prototype test vehicles. 

Many of the engines parts have been tested at spaceX's test stand at McGregor Texas, powered by densified liquid methane and liquid oxygen propellants.

The first test of the Raptor engine in Sept 2016

 Raptor engine test Sept 2016 at McGregor.

Parts of the Raptor engine are being 3-D printed using titanium and Inconel alloys as are the SuperDraco engines used on the Dragon V2.

The Raptor is slated to use a methane combustion cycle running oxygen-rich under lower temperatures and chamber pressures, reducing the coking and also a more benign turbine environment.

This should help its lifespan and maintenance due to less material fatigue and its lower engine weight.

The Raptor engine will have two versions a sea-level version that will be used on the first stage of the booster and a vacuum version that will propel the second stage/spacecraft.

The thrust is 3050kN  (up from the planned  2,300 kilonewtons)  around three times the thrust of the SpaceX Merlin 1D engine, that is about one-third of the thrust of the F-1 engine used on the Apollo Saturn V rocket that went to the moon.

New smaller Raptor engine for BFR version 1.0

250Bar

Vacuum engines: Exit diameter 2.4m, Thrust 1,900 kN, Isp 375 s

Sea level engines: Exit diameter 1.3m, Thrust (SL) 1,700 kN, Isp (SL) 330s, Isp (Vac) 356s

Merlin and Raptor Engine video simulation Talk