First-stage structure
The lightweight cylindrical structure carries launch loads and encloses the first-stage tanks.
Two-stage RocketINTERACTIVE 3D
Every component has a purpose. Discover how they work together.
First stage firing. The full stack is attached; the fairing protects the satellite.
FROM FUEL TO MOTION
One flow. Continuous thrust.
Supply, injection, combustion, and expansion happen continuously during firing.
ROCKET ENGINE GUIDE
ILLUSTRATIVE SECTION
SUPPLY STAGE
Carry everything needed to burn.
Fuel and oxidizer are stored separately on board. Unlike an air-breathing engine, a rocket brings its oxidizer with it and can operate in space.
Amber: fuel · blue: oxidizer2launch stages
2propellants: fuel and oxidizer
Understand the engine, step by step
Follow the propellants, explore steering and stage separation, and identify each assembly.
Rocket parts and their functions
Fuel tank
Stores liquid fuel separately from the oxidizer. Pumps deliver it to the engine; the amber color is a teaching convention.
Oxidizer tank
Carries liquid oxygen so the engine can burn fuel without taking in air, including in the vacuum of space.
Propellant feed lines
Separate fuel and oxidizer lines lead toward the pumps and injector. The fluids mix at the injector, not inside their storage tanks.
Turbopump assembly
Raises propellant pressure before injection. This simplified assembly omits the turbine drive circuit and does not represent a particular engine cycle.
Gimbaled main engine
An injector mixes propellants in a combustion chamber. Hot gas accelerates through a throat and expanding nozzle. Pivoting the assembly redirects thrust and creates steering torque.
Interstage adapter
Connects the stages, transfers loads and shields the upper-stage engine. Separation releases the spent lower stage before upper-stage ignition.
Upper-stage structure
Supports the upper-stage tanks and payload after the heavy first stage is discarded.
Upper-stage tanks
A simplified paired-tank assembly supplies the upper engine. Fuel and oxidizer remain in separate compartments.
Upper-stage engine
A larger expansion nozzle suits low ambient pressure. It accelerates the remaining vehicle after first-stage separation.
Guidance and avionics
Sensors and computers estimate attitude and motion, then command actuators to keep the vehicle on its planned trajectory.
Satellite payload
The mission cargo rides inside the protective fairing. A deployment mechanism releases it after the launch vehicle reaches the intended conditions.
Left payload fairing
Protects the payload from aerodynamic loads and heating during atmospheric ascent. It separates when atmospheric protection is no longer needed.
Right payload fairing
The second half of the protective shell separates with its partner, reducing carried mass during the rest of ascent.