Merlin is a rocket engine design developed by SpaceX for use on its Falcon 1 and Falcon 9 rockets. Merlin uses RP-1 and liquid oxygen as propellants in a gas-generator power cycle. The Merlin engine is designed for sea recovery and reuse. The pintle style injector at the heart of Merlin was first used in the Apollo Program for the lunar module landing engine, one of the most critical phases of the mission. Propellants are fed via a single shaft, dual impeller turbo-pump. The turbo-pump also provides high pressure kerosene for the hydraulic actuators, which then recycles into the low pressure inlet. This eliminates the need for a separate hydraulic power system and means that thrust vector control failure by running out of hydraulic fluid is not possible. A third use of the turbo-pump is to provide roll control by actuating the turbine exhaust nozzle.
Revisions
Merlin 1A
The initial version, the Merlin 1A, used an inexpensive, expendable ablatively cooled carbon fiber composite nozzle.
Merlin 1B
The Merlin 1B rocket engine is an upgraded version of the Merlin engine developed by SpaceX for its Falcon 1 launch vehicles. It is capable of producing 85,000 lbf of thrust, over its predecessor's 77,000 lbf. The Merlin 1B has been enhanced over the 1A with a turbine upgrade (from 1490 kW to 1860 kW). Initial use of the Merlin 1B was to be on the Falcon 9 heavy launch vehicle, on whose first stage there would have been a cluster of nine of these engines. Due to experience from the Falcon 1's first flight, the 1B will not be used on a flight vehicle. SpaceX has moved its Merlin development to the Merlin 1C, which is regeneratively cooled.
Merlin 1C
The Merlin 1C uses a regeneratively cooled nozzle and combustion chamber, and has been completed with the mission duty firing (170 seconds) in November, 2007. [1][2]
Merlin 2
The Merlin 2 is a planned future development with F-1-class performance currently under development by SpaceX. It is a considerable upgrade from its predecessors (Merlin 1A and Merlin 1B), and is better classified as an entirely new engine. Elon Musk, SpaceX's founder, has stated that the Merlin 2 will be a powerful, regeneratively cooled engine. It is intended to be a scaled down version of a future planned engine who's performance will be in the range of the famed F-1 used on the Saturn V rockets that sent men to the moon, around 1.5 million lbf (6.7 MN of thrust). Merlin 2 is intended for use on SpaceX's future "BFR". The Merlin 2 itself will be a modest upgrade to the Merlin 1, featuring a regeneratively cooled nozzle, higher chamber pressure and higher specific impulse. [3] Upgrading the Falcon 9 to Merlin 2 engines should allow Falcon 9 to compete with Sea Launch's Zenit in all weight classes.
Engine details
Performance
Current published ratings:[4]
- Sea level thrust: 102,000 lbf (454 kN)
- Vacuum thrust: 115,000 lbf (512 kN)
- Chamber pressure: 6.14 MPa (890 psi)
- Sea level Isp: 255 s (2.6 kN·s/kg)
- Vacuum Isp: 304 s (3.0 kN·s/kg)
- Thrust-to-weight ratio (fully accounted): 96
Operations
- Fuel: RP-1 rocket grade kerosene
- Oxidizer: Liquid oxygen
See also
References
- ^ SpaceX Completes Development of Merlin Regeneratively Cooled Rocket Engine. Business Wire.
- ^ SPACEX COMPLETES DEVELOPMENT OF MERLIN REGENERATIVELY COOLED ROCKET ENGINE. SpaceX. Retrieved on 2007-11-14.
- ^ "Big plans for SpaceX", The Space Review, November 14, 2005. Retrieved on 2007-11-14.
- ^ SpaceX Merlin Engine. SpaceX.
- Race for Next Space Prize Ignites: Wired article describing successful test firing
