J-2X

Rocketdyne's J-2 was America's largest production liquid hydrogen fueled rocket engine before the Space Shuttle main engines (SSME), and is being revived in support of NASA's return to the Moon.The J-2 was a major component of the Saturn V rocket. Five J-2 engines were used in the S-II, the second stage of the Saturn. One J-2 engine was used in S-IVB, the third stage of the Saturn V, and the second stage of the Saturn IB. There were proposals to use various numbers of J-2 engines in the upper stages of the planned Nova rocket.
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