Fly Me to the Moon...

Although the future of manned space exploration in the post-Shuttle era is still in question, development continues apace at Pratt & Whitney Rocketdyne (prattwhitneyrocketydyne.com), as it is engineering the J-2X rocket engine for the Ares Projects Office at NASA’s Marshall Space Flight Center. The engine is being developed for NASA’s Constellation Program, which is an undertaking to develop crew and launch vehicles for exploration of places like the Moon and Mars at some point in the future.

The engine is intended to power the upper stages of the Ares I crew launch vehicle and the Ares V cargo launch vehicle.

An interesting aspect of the product development of the J-2X is that it is based on the know-how developed for the J-2 engine, which was used during the Apollo-Saturn program. Consequently, lessons learned are being deployed for this new engine.

The J-2X is what’s known as a “re-startable, expendable gas generation cycle engine.” It uses liquid hydrogen and oxygen as propellants.

The engine is comparatively compact. It measures some 185-in. long and 120-in. in diameter at the end of the nozzle. It weighs 5,450 lb. However, it also produces 294,000 lb. of thrust, which is enough to put the Ares I upper stage in low-Earth orbit.

According to Pratt & Whitney Rocketdyne, the J-2X fuel pump performance is analogous to being able to empty a 20,000-gallon swimming pool in two minutes.
The engine’s first hot-fire tests are to be performed early in 2011 at the Stennis Space Center.