Merlin (rocket engine)

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Merlin 1A engine

The Merlin rocket engine is used in the main stage of the SpaceX Falcon rocket and is an in-house development. A mixture of liquid oxygen ( LOX ) and the rocket fuel RP-1 is used as fuel in a gas generator-engine cycle. The first test of a complete Merlin 1 engine took place after a two-year development period in June 2004.

variants

Merlin 1A

Merlin 1C for the Falcon 9

The first generation 1A of the engine was ablative cooled. On all flights the engine was used as the basis for a Falcon 1 rocket. The first flight on March 24, 2006 failed shortly after take-off due to a fuel leak. On the second flight on March 21, 2007, the engine worked perfectly.

Merlin 1B

The intermediate version 1B was never used.

Merlin 1C

The third generation 1C was first used on the third flight on August 6, 2008. Instead of the previously used ablative cooling, the fuel was used for cooling. The additional fuel residues in the cooling loop led to an error in the staging, as when turning off the engine of the residual thrust fell more slowly than expected and occurred subsequent separation blowing up too early. As a result, the two steps collided, damaging the upper level.

In the following flight of the Falcon 1, the problem was corrected, the rocket successfully reached earth orbit .

Merlin 1D

Merlin 1D engines

For the Falcon Heavy and a performance-enhanced version of the Falcon 9 , the Merlin 1D, which has further increased thrust, was developed. Reinforced to 825 kN, the Merlin 1D v. 2 is to be used in the Falcon 9FT Block 5 (internal Falcon 9 2.0), the final version of the Falcon 9FT.

When a Falcon 9 Block 5 started for the first time on May 11, 2018, the thrust was given as "190000 pound-force", corresponding to 845 kN. During the flight the engine pressure is reduced so that the thrust remains constant at 845 kN even in a vacuum.

The thrust of the Block 5 vacuum engine has been increased by 5% from 210,000 lbf to 220,000 lbf, corresponding to 978.6 kN. At the first start, the block 5 vacuum engine of the upper stage was still operated with the old thrust.

Performance metrics

parameter Merlin 1A Merlin 1C Merlin 1C Vac Merlin 1D v1.1 Merlin 1D Vac v1.1 Merlin 1D v1.2 Merlin 1D Vac v1.2 Merlin 1D Block 5 Merlin 1D VAC

Block 5

fuel LOX / RP-1
Ground thrust 340 kN 423 kN 654 kN 756 kN 845 kN
Vacuum thrust 378 kN 483 kN 411 kN 716 kN 815 kN 825 kN 913 kN 845 kN 979 kN
Specific impulse in a vacuum 3,041 Ns / kg 2981 Ns / kg 3,295 Ns / kg 3,040 Ns / kg 3,355 Ns / kg 3,050 Ns / kg 3,424 Ns / kg
Fuel throughput 140 kg / s
Combustion chamber pressure 6.14 MPa 9.72 MPa
Relaxation relationship 14.5 117 16 117 16 165
Dimensions 760 kg 522 kg 470 kg
Thrust-to-mass ratio [dN / kg] 94 96 150 180

Web links

Commons : Merlin (rocket engine)  - Collection of images, videos and audio files

Individual evidence

  1. ↑ SpaceX: Press release on the failure of Flight 3 , August 6, 2008 (English)
  2. ↑ a b Merlin SpaceX rocket engine. Retrieved March 12, 2017 .
  3. ↑ a b spacexcmsadmin: Bangabandhu Satellite-1 Mission . In: SpaceX . January 29, 2016 ( spacex.com [accessed on May 14, 2018]): "On the SpaceX Webcast T- 07.45" The Trust of these Merlin 1D is increased from 176000 pound-force to 190000 pound force. "
  4. ^ SpaceX Merlin Engine . SpaceX. Archived from the original on January 3, 2011. Retrieved January 12, 2011.
  5. ↑ spacexcmsadmin: SpaceX Completes Qualification Testing of Merlin Regeneratively Cooled Engine . In: SpaceX . February 25, 2008 ( spacex.com [accessed October 8, 2016]).
  6. ^ Falcon Heavy Merlin Engines. April 12, 2013, accessed June 17, 2015 .
  7. ↑ AmericaSpace: Elon Musk Discusses New SpaceX 'Block 5' Rocket. May 10, 2018, accessed on May 16, 2018 : "8:20 Elon Musk:" The vacuum Merlin engine increased trust by 5% to ... 220000 pound force ... "
  8. ↑ Merlin 1A in the Encyclopedia Astronautica , accessed January 17, 2014
  9. ↑ http://aerospaceblog.wordpress.com/2010/12/03/merlin-rocket-engine/ , accessed January 22, 2014.