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RL10 Engine

Overview

For nearly 60 years, Aerojet Rocketdyne’s RL10 engine has played a vital role in placing hundreds of military, government and commercial spacecraft into Earth’s orbit and beyond. The engine has helped send spacecraft to explore every planet in our solar system, including Voyager 1 and Voyager 2, the first two spacecraft to reach interstellar space.

Today, multiple  RL10 variants carry the engine’s legacy forward as the launch industry’s “workhorse,” powering the upper stages of United Launch Alliance’s (ULA) Atlas V and Delta IV Heavy rockets. Two RL10 engines power the upper stage of ULA’s new Vulcan Centaur rocket.

RL10 engines also help power NASA’s Space Launch System (SLS) rocket, designed to carry astronauts to deep-space destinations aboard the Orion exploration spacecraft. A single RL10 powered the Interim Cryogenic Propulsion Stage on Artemis I, an un-crewed test flight of SLS and Orion. Four RL10 engines will support the more powerful Exploration Upper Stage that is being developed for future versions of SLS.

Aerojet Rocketdyne, an L3Harris Technologies company, has developed and is working to qualify a modern version of the engine known as the RL10C-X that includes major components built using 3-D printing technology. Incorporating 3D printing into the manufacturing process will reduce lead times and cost while maintaining the outstanding performance and reliability customers have come to expect.

Key Features

  • 1959: First RL10 test
  • 1963: First successful Atlas Centaur flight (two RL10 engines powered upper stage)
  • 1964: Saturn S-4 Launch (six RL10 engines powered upper stage)
  • 1993: First DC-X "Delta Clipper" flight (four RL10A-5 engines powered vehicle)
  • 2002: First Atlas V flight (two RL10A-4-2 engines powered Centaur upper stage)
  • 2009: 400th RL10 engine flight
  • 2010: Demonstrated deep-throttling from 104 percent of rated power down to 5.9 percent (an unprecedented thrust range of 17.6:1)
  • 2013: RL10 marks 50 years of service
  • 2014: First flight of RL10C-1
  • 2020: 500th RL10 engine flight
  • 2021: First operational use of an RL10 engine equipped with 3D-printed components
  • 2022: A single RL10 powered the Interim Cryogenic Propulsion Stage on the first SLS mission

Models RL10B-2, RL10C-2-1

Launch VehicleDelta IV
Thrust24,750 lbf
Weight664 lbs
FuelLiquid hydrogen
OxidizerLiquid oxygen
Nominal Mixture Ratio5.88:1
Specific Impulse465.5 sec
Length86.5" (stowed), 163.5" (deployed)
Nozzle Diameter84.5"

 

Model RL10A-4-2

Launch VehicleAtlas V
Thrust22,300 lbf
Weight370 lbs
FuelLiquid hydrogen
OxidizerLiquid oxygen
Nominal Mixture Ratio5.5:1
Specific Impulse451.0 sec
Length90"
Nozzle Diameter46"

 

Model RL10C-1

Launch VehicleAtlas V
Thrust22,890 lbf
Weight420 lbs
FuelLiquid hydrogen
OxidizerLiquid oxygen
Nominal Mixture Ratio5.5:1
Specific Impulse449.7 sec
Length86"
Nozzle Diameter57"

 

Model RL10C-1-1

Launch VehicleAtlas V, Vulcan Centaur
Thrust23,825 lbf
Weight415 lbs
FuelLiquid hydrogen
OxidizerLiquid oxygen
Nominal Mixture Ratio5.5:1
Specific Impulse453.8 sec
Length96.7"
Nozzle Diameter62"

 

Model RL10C-X

Launch VehicleVulcan Centaur
Thrust24,120 lbf
Weight510 lbs
FuelLiquid hydrogen
OxidizerLiquid oxygen
Nominal Mixture Ratio5.5:1
Specific Impulse460.9 sec
Length130.4"
Nozzle Diameter73.7"

 

Model RL10C-3

Launch VehicleSLS Exploration Upper Stage
Thrust24,340 lbf
Weight508 lbs
FuelLiquid hydrogen
OxidizerLiquid oxygen
Nominal Mixture Ratio5.7:1
Specific Impulse460.1 sec
Length124.3"
Nozzle Diameter73"

Resources

  • RL10 Propulsion System Data Sheet

    RL10 Propulsion System Data Sheet

  • Premier Propulsion Provider for the U.S. Air Force Data Sheet

    Premier Propulsion Provider for the U.S. Air Force Data Sheet

Featured News

Aerojet Rocketdyne Races to the Moon with High-Performance RS-25 Engines

Editorial | 10. 20. 2023

Aerojet Rocketdyne Races to the Moon with High-Performance RS-25 Engines

Aerojet Rocketdyne Races to the Moon with High-Performance RS-25 Engines

Aerojet Rocketdyne Races to the Moon with High-Performance RS-25 Engines

Editorial | 10. 20. 2023

Aerojet Rocketdyne Races to the Moon with High-Performance RS-25 Engines

The upper stage is pulled by a truck

Editorial | 09. 10. 2023

Powering ULA’s Atlas V Mission for the NRO and U.S. Space Force

Aerojet Rocketdyne, an L3Harris Company

Press release | 07. 28. 2023

L3Harris Completes Aerojet Rocketdyne Acquisition

L3Harris Nexus

Press release | 04. 11. 2022

Aerojet Rocketdyne Secures its Largest RL10 Engine Contract from United Launch Alliance

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