NozzleExtendable / Deployableby Aerojet Rocketdyne / Snecma (carbon-carbon)
Typical Specifications
Retracted Ratio
84:1
Extended Ratio
285:1
Extension Material Temp
Up to 1,650u00b0C (radiation cooled)
Operating Principle
A radiation-cooled carbon-carbon nozzle extension is held in a retracted position during launch. After staging, a deployment mechanism extends the nozzle to its full length, increasing the expansion ratio for optimal vacuum performance.
The RL-10B-2 features a deployable carbon-carbon nozzle extension that increases the area ratio from 84:1 to 285:1 after stage separation, dramatically improving vacuum performance. The extension is stowed in a compact configuration during the boost phase and deploys mechanically before upper stage ignition. This innovation allows the engine to achieve 465.5 seconds of specific impulse.
Materials
Used In Engines
Common Failure Modes
Deployment mechanism jam, carbon-carbon cracking from thermal shock, seal failure at interface, structural failure during deployment
Recent Innovations
Carbon-carbon composite construction allows radiation cooling to 1,650°C without active cooling, compact stowage saves fairing volume, spring-loaded deployment mechanism
