RS-68
The Rocketdyne RS -68 ( Rocket System 68 ) is a liquid hydrogen / liquid oxygen rocket engine of the company Rocketdyne.
Properties
The engine generates a thrust of 2.9 Mega Newton near the ground and 3.3 Mega Newton in a vacuum. It is used in the first stage and the booster of the missile Delta IV and should be used in the Ares V. The RS -68 was created with the aim to simplify the engine compared to the space shuttle main engine SSME significantly in order to make it more affordable can. This has been largely dispensed with, the efficiency of the engine. For example, effective production methods were used, and it was an ablative cooling of the thrust nozzle used. By these measures the mass of the engine increased, the production costs decreased considerable. The engine has a mass of 6696 kg, has at the start of a specific impulse of 3580 Ns / kg or 365 s (in vacuum 4022 Ns / kg or 410 s ) and developed when lifting a thrust of 2,891 kN ( 3,312 kN in vacuum ), making it the second most powerful LOX/LH2-Triebwerk world. It is only surpassed by the next version RS- 68A. The performance of the engine can be adjusted from a minimum of 60% to a maximum of 102% of the nominal thrust. An RS -68 will cost about 14 million U.S. dollars. When the engine is the first new development of a large rocket engine in the U.S. since the SSME over 20 years ago.
The enhanced version RS- 68A had on 25 September 2008 its first run. His thrust can be throttled as in the previous version. The RS- 68A has at the bottom a specific impulse of 3570 Ns / kg and in the vacuum of 4,072 Ns / kg. The thrust force is 3,496 kN at lifting 3,065 kN and a vacuum. The RS- 68A was used for the first time on June 29, 2012. All three CBCs a Delta IV Heavy were equipped with them.