This cryogenic bipropellant combination offers a very high specific impulse, making it highly efficient for upper stages and main engines. The liquid hydrogen acts as the fuel while the liquid oxygen serves as the oxidizer. Because both components must be kept at extremely low temperatures to remain liquid, handling requires heavy insulation and complex tank designs.
We need to chill down the hydrolox lines before we open the main valves for engine start.
The exhaust from a hydrolox engine is mostly superheated water vapor, which is why these rockets often produce a nearly invisible flame rather than a bright, smoky plume.
Also heard as
- LH2/LOX
Related terms
Chemical rocket
A propulsion system that generates thrust through the exothermic reaction of chemical propellants.
RP-1
Rocket Propellant-1, a highly refined form of kerosene used as rocket fuel.
Preburner
A small combustion chamber in a staged-combustion rocket engine used to drive the turbopumps.
Gas generator
A gas generator burns propellant to create high-pressure gas that drives turbines or pumps.