Proven Performance

The AR-22 engine is the main propulsion for Boeing and DARPA’s Experimental Spaceplane (XS-1), the Phantom Express.  Aerojet Rocketdyne is assembling the AR-22 engine using parts that remained in its and NASA’s inventories from early versions of the Space Shuttle Main Engine (SSME).

Aerojet Rocketdyne's SSME is the world’s most reliable and highly tested large rocket engine ever built, and operates at greater temperature extremes than any mechanical system in common use today. The SSME powered 135 space shuttle missions with a demonstrated reliability exceeding 0.9996 over 1,100,000 seconds of hot-fire experience. An upgraded version of the SSME, known as RS-25, is slated to power NASA’s Space Launch System rocket.

Key Features

The AR-22 is a reusable, staged-combustion cycle engine that uses a mixture of liquid oxygen and liquid hydrogen.  The engine operates in temperature extremes from negative 423 degrees Fahrenheit to 6,000 degrees Fahrenheit and at pressures exceeding 6,900 pounds per square inch.