// PROPULSION SYSTEMS AND ENGINE TECHNOLOGY TERM
Expander Cycle
The expander cycle is a type of rocket engine where the fuel is heated and expanded by passing it through the engine's hot parts, like the combustion chamber walls, to drive the turbopumps before being injected into the combustion chamber itself.
TECHNICAL DEFINITION
The expander cycle is a closed-cycle rocket engine design where cryogenic propellant (typically fuel) is first circulated through cooling channels in the combustion chamber and nozzle to absorb waste heat, then expands to power the turbopumps that feed propellants, and finally enters the combustion chamber for thrust generation.
BACKGROUND
The staged combustion cycle is a power cycle of a bipropellant rocket engine. In the staged combustion cycle, propellant flows through multiple combustion chambers, and is thus combusted in stages. The main advantage relative to other rocket engine power cycles is high fuel efficiency, measured through specific impulse, while its main disadvantage is engineering complexity.
READ MORE ON WIKIPEDIASYNONYMS & ALIASES
- Expander-bleed cycle
- Expander-tapped bleed cycle
- Closed expander cycle
USAGE NOTE
This cycle is favored for its efficiency and reusability, often used in upper-stage engines or engines requiring multiple restarts due to its relatively simple plumbing and high specific impulse.
DEVELOPERS
Organizations developing technology related to Expander Cycle.
Aerojet Rocketdyne
A leading aerospace manufacturer that developed and continues to produce the RL10 engine family, one of the most well-known and widely used expander cycle engines, powering upper stages of launch vehicles like Atlas V and Delta IV.
JAXA (Japan Aerospace Exploration Agency)
Japan's national aerospace agency, which developed the LE-5B and LE-9 engines, both expander bleed cycle engines used for the second stages of the H-IIA/B and H3 launch vehicles respectively.
Mitsubishi Heavy Industries (MHI)
A major Japanese industrial corporation that manufactures the LE-5B and LE-9 expander bleed engines for JAXA's H-IIA/B and H3 rockets, playing a critical role in their production and operational use.
ArianeGroup
A joint venture between Airbus and Safran, developing and producing propulsion systems for the Ariane family of launchers. They are responsible for the Vinci engine, an expander cycle engine for the Ariane 6 upper stage.
Blue Origin
An American aerospace manufacturer and spaceflight services company that developed the BE-3 engine, an expander cycle engine used on the New Shepard suborbital vehicle and the BE-3U for the New Glenn upper stage.
NASA (National Aeronautics and Space Administration)
The U.S. government agency responsible for the civilian space program, aeronautics, and aerospace research. NASA has historically funded and overseen the development of expander cycle engines like the RL10 and conducts ongoing research into advanced propulsion cycles at various centers.