Main Engine Cut Off

AR-22 Fires 10 Times in 240 Hours

Aerojet Rocketdyne successfully fired its AR-22 booster rocket engine an unprecedented 10 times in 240 hours at NASA Stennis Space Center, demonstrating the feasibility of rapidly recycling the engine to enable a reusable launch vehicle capable of high-tempo, aircraft-like flight operations.

The liquid-oxygen and hydrogen-fueled AR-22 engine, capable of generating more than 375,000 pounds of thrust, fired at full throttle during the tests, each lasting at least 100 seconds in duration. After each firing, Aerojet Rocketdyne technicians carried out pre-planned inspections and data reviews in preparation for the next test.

One hundred seconds is a curious firing duration, as there is no way that the flight profile of Phantom Express would lead to a 100-second first stage burn.

Either way, the total firing duration was about two Shuttle flights to orbit, so total duration isn’t the surprising thing here—it’s the fact that they could turn the engine around quick enough to pull this off.

We’ll see where this goes from here, but I don’t have high hopes.