New Rocket Engine Combustion Cycle Technology Testing Reaches 100% Power Level

  • Published
  • By Plans and Programs Directorate
  • AFRL/XP
WRIGHT-PATTERSON AIR FORCE BASE, Ohio --  America's rocket propulsion capabilities recently achieved an important milestone. During tests conducted at the National Aeronautics and Space Administration's (NASA) Stennis Space Center (near Bay Saint Louis, Mississippi), the nation's only staged-combustion liquid booster rocket engine now in development reached "steady-state" operation at 100% power level, providing "mainstage" performance for the first time.

The engine cycle demonstrator, dubbed the Integrated Powerhead Demonstrator (IPD), is a ground demonstrator engine that combines the latest innovations in rocket engine propulsion technologies.

Engineers from Pratt & Whitney Rocketdyne, Inc., and Aerojet designed, developed, and tested the IPD engine under AFRL's program direction and NASA's technical direction. The new engine technology, designed to achieve 250,000 lbs of thrust, used liquid oxygen and liquid hydrogen to achieve the first US demonstration of the full-flow staged-combustion (FFSC) cycle. With a goal as a reusable rocket engine system capable of up to 200 flights, the engine design utilizes high-performance, long-life technologies and materials.

The FFSC cycle uses a fuel-rich preburner to drive the fuel turbopump and an oxidizer-rich preburner to drive the oxygen turbopump. Because the preburners utilize and burn all of the propellants, more mass flow is available to drive the respective turbines than in a conventional staged-combustion cycle engine. The additional power enables lower turbine temperatures and hence less stress, translating into longer turbine life, a key factor for reusable rocket engine life.

In addition, the use of oxidizer-rich gas in the oxidizer turbine and fuel-rich gas in the fuel turbine eliminates the need for a complex propellant seal in the pumps, prevents inadvertent propellant mixing, and increases engine system reliability. The innovative engine cycle and turbopump design also includes a hydrostatic bearing technology that literally floats the turbine shaft on rocket propellants, alleviating wear and enabling high reusability.

Although the IPD engine will not fly, its technologies will make their way into future rocket engines. This program provides a cost-effective manner in which high-payoff technologies can be demonstrated at component and engine system levels.