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Aerojet Rocketdyne

AJ10-190 engine

Hypergolic MMH/MON-3 engine designed by Aerojet Rocketdyne for the Space Shuttle Orbital Maneuvering System; refurbished units are the Orion European Service Module main engine. NASA's design paper names a stainless steel liner, an electroformed nickel shell and a radiation-cooled columbium nozzle extension.

Engines
Product IDaerojet-aj10-190
Visit Aerojet Rocketdyne
Thrust
26.7 kN
Thrust class
About 6,000 lbf
Specific impulse
315.1 s
Mixture ratio (oxidizer to fuel)
1.65

In short

Hypergolic MMH/MON-3 engine designed by Aerojet Rocketdyne for the Space Shuttle Orbital Maneuvering System; refurbished units are the Orion European Service Module main engine. NASA's design paper names a stainless steel liner, an electroformed nickel shell and a radiation-cooled columbium nozzle extension.

Application

The AJ10-190 was the Orbital Maneuvering System engine of the Space Shuttle Orbiter, one in each pod, used for orbit insertion, in-orbit manoeuvres and deorbit. Refurbished Shuttle units are now the main engine of the European Service Module that pushes NASA's Orion capsule to the Moon on Artemis missions. Its stainless-steel-lined, nickel-jacketed chamber and radiation-cooled columbium nozzle are a reuse case for storable-propellant engines.

How it is built

Thrust chamber assembly

  • Chamber liner
  • Chamber outer shell
  • Aft flange and fuel inlet manifold assembly
  • Regenerative cooling passages (120)
  • Combustion chamber heater (added for Orion)

Injector

  • Injector (flat-face, photo-etched platelets)
  • Acoustic cavities

Nozzle extension

  • Nozzle extension (area ratio 6:1 to 55:1)
  • Nozzle mounting flange

Propellant valve and feed

  • Bipropellant valve (series, pneumatically actuated)
  • Series valve assembly seals (replacement planned from Artemis 3)
  • Inlet filters
  • Engine nitrogen supply and purge

Gimbal and electrical

  • Gimbal ring (inlet-manifold mounted)
  • Wiring harnesses (replaced for Orion)
Where the parts areNumber of parts we have listed in each group
  • Thrust chamber assembly6
  • Propellant valve and feed4
  • Injector2
  • Nozzle extension2
  • Gimbal and electrical2

What it is made of

  • columbium (alloy grade not stated)

    Used in Nozzle extension (area ratio 6:1 to 55:1).

  • electroformed nickel

    Used in Chamber outer shell.

  • stainless steel (grade not stated in the quoted text)

    Used in Chamber liner.

How it connects to other things

Used in

  • Orion spacecraft

    NASA

    Main engine (OMS-E) of the European Service Module; first six Artemis missions use refurbished Shuttle units

  • European Service Module

    Main engine of the Orion European Service Module; one engine

Launches

  • Destiny laboratory module (ISS)

    NASA / Boeing

    Space Shuttle orbital maneuvering system engine, two on the orbiter; aerojet OMS engine, 6,000 lbf, MMH/NTO; used for orbit insertion and deorbit; launcher engine, not carried by the vehicle

Builds on

  • Space Shuttle Orbiter Orbital Maneuvering System (OMS)

    Artemis I flew an engine refurbished from the Shuttle OMS; 19 earlier Shuttle missions

  • Apollo Command and Service Module

    North American Aviation

    Valve-level heritage only: a NASA technology contract to improve the Apollo SPS bipropellant valve fed the OMS valve design (the 1985 paper says the results were used to design the OMS valve)

Made or supplied by

  • Aerojet Rocketdyne

    Designed and developed the OMS engine for the Shuttle program

Products that use the same materials

  • RS-25 engine

    Aerojet Rocketdyne

    electroformed nickelstainless steel
    Where each one is used

    electroformed nickel. Here: Chamber outer shell. There: Chamber liner exterior.

    stainless steel. Here: Chamber liner. There: Nozzle coolant tubes (1,080 tubes, brazed to jacket); Oxidizer heat exchanger coil.

  • Apollo Command and Service Module

    North American Aviation

    columbiumstainless steel
    Where each one is used

    columbium. Here: Nozzle extension (area ratio 6:1 to 55:1). There: SPS nozzle extension.

    stainless steel. Here: Chamber liner. There: Outer shell (heat shield structure); VHF scimitar antennas and more.

  • Atlas V

    United Launch Alliance

    columbiumstainless steel
    Where each one is used

    columbium. Here: Nozzle extension (area ratio 6:1 to 55:1). There: Centaur extendible nozzle (RL10, dual engine).

    stainless steel. Here: Chamber liner. There: Centaur propellant tanks.

  • RL10 engine

    Aerojet Rocketdyne

    columbiumstainless steel
    Where each one is used

    columbium. Here: Nozzle extension (area ratio 6:1 to 55:1). There: RL10A-4-2 fixed columbium nozzle extension (51 cm).

    stainless steel. Here: Chamber liner. There: RL10C-1 thrust chamber tubes; Fuel pump drive shaft and bearings and more.

  • Lunar Module Descent Engine (LMDE)

    TRW

    columbiumstainless steel
    Where each one is used

    columbium. Here: Nozzle extension (area ratio 6:1 to 55:1). There: Pintle tip, qualification version.

    stainless steel. Here: Chamber liner. There: Pintle tip, original; Flow-control valve bellows and more.

What we do not know

Stainless steel grade, columbium alloy grade, injector and valve materials, gimbal ring material and bolt or seal materials are not stated. The engine was refurbished for Orion; no source lists replaced materials beyond harnesses, sensors, heater and valve seals.

The detailed data

What is written above is built from these numbers and quotes. Each row links to the page it was taken from. Get all of it as JSON, or ask our MCP server.

Features

  • Hypergolic, pressure-fed storable-propellant engine with regenerative and film cooling
  • Radiation-cooled columbium nozzle extension reaching an area ratio of 55:1
  • Chamber built from a stainless steel liner with an electroformed nickel shell
  • Flat-face injector made from photo-etched platelets
  • Gimbals in pitch and yaw on an inlet-manifold gimbal ring
  • Fired through a pneumatically actuated series bipropellant valve
  • A post-Apollo NASA technology contract for the orbital maneuvering engine started from improving the Apollo SPS bipropellant valve
  • Reused on Orion: first six missions use refurbished Shuttle engines, new engines from Artemis VII
  • Orion changes: added combustion chamber heater and redundant chamber pressure and injector temperature sensors

Specifications

WhatValue
Thrust26.7 kN
Thrust classAbout 6,000 lbf
Specific impulse315.1 s
Mixture ratio (oxidizer to fuel)1.65
PropellantsMonomethylhydrazine (MMH) and nitrogen tetroxide with 3% mixed oxides of nitrogen (MON-3)
Cooling and typePressure fed, hypergolic, regeneratively and film cooled, fixed thrust
Nozzle area ratio55:1
GimbalTwo axes, pitch and yaw
Maximum burn duration (Orion use)1030 s
Starts (Orion use)10 maximum
Unfuelled mass118 kg (260 lb), per Encyclopedia Astronautica
Engines per OMS pod (Shuttle)One liquid-propellant rocket engine per OMS pod
Engines per spacecraft (Orion)One main engine on the European Service Module
Artemis I engine historyRefurbished Shuttle engine that flew 19 missions, STS-41G (1984) to STS-112 (2002)
Orion flightArtemis I launched 16 November 2022
First Shuttle flight12 April 1981, Columbia (per Encyclopedia Astronautica)
Nominal thrust requirement (Shuttle design)About 6,000 lb, 4,000 lb lower limit

Materials in detail

Each material named in the sources: where it is used here, which other products use it, and its key numbers when its material page exists.

Every part we have

Chamber, nozzle extension, injector, valve and gimbal inventory from NASA's 1985 OMS design paper and the 2024 Artemis I engine paper. Materials are stated for three parts only (liner, outer shell, nozzle extension); injector, valve, gimbal and harness materials are not published in the sources found.

Material IDs

stainless-steelelectroformed-nickelcolumbium-niobium
Thrust chamber assembly6
PartMaterialFinish and standardMade by
Chamber liner“The combustion chamber was composed of three main parts: a stainless steel liner” stainless steel (grade not stated in the quoted text)stainless-steel — —
Chamber outer shell“a stainless steel liner, an electroformed nickel shell, and an aft flange and fuel inlet manifold” electroformed nickelelectroformed-nickel — —
Aft flange and fuel inlet manifold assembly“a stainless steel liner, an electroformed nickel shell, and an aft flange and fuel inlet manifold” Not said — —
Regenerative cooling passages (120)“The chamber contained 120 longitudinal, milled, rectangular-shaped passages.” Not said — —
Combustion chamber heater (added for Orion)“led to the decision to implement a heater system on the combustion chamber” Not said — —
Chamber pressure and fuel injector temperature sensors (redundant, added for Orion)“Additional changes to the OMS-E for Artemis include the addition of redundant chamber pressure and fuel injector temperature sensors” Not said — —
Injector2
PartMaterialFinish and standardMade by
Injector (flat-face, photo-etched platelets)“like-on-like pattern composed of eight photo-etched platelets” Not said — —
Acoustic cavities“The baseline engine incorporated a platelet injector, acoustic cavities for stability” Not said — Describes the 1974 baseline engine configuration
Nozzle extension2
PartMaterialFinish and standardMade by
Nozzle extension (area ratio 6:1 to 55:1)“was radiation cooled and was constructed entirely of columbium” columbium (alloy grade not stated)columbium-niobium — The same paper says the panels were butt-welded to form two cones
Nozzle mounting flange“The mounting flange consisted of a bolt ring made from a forging” Not said — —
Propellant valve and feed4
PartMaterialFinish and standardMade by
Bipropellant valve (series, pneumatically actuated)“The OMS-E fires via a pneumatically actuated series bipropellant valve.” Not said — —
Series valve assembly seals (replacement planned from Artemis 3)“New seals in Series Valve Assembly (Artemis 3+)” Not said — —
Inlet filters“Filters were contained at the inlets of the feedlines for ease of access.” Not said — —
Engine nitrogen supply and purge“The engine carries its own supply of nitrogen to fire the engine” Not said — —
Gimbal and electrical2
PartMaterialFinish and standardMade by
Gimbal ring (inlet-manifold mounted)“mounting it on the inlet manifold-mounted gimbal ring” Not said — —
Wiring harnesses (replaced for Orion)“The wiring harnesses on the engine were also replaced” Not said — —

What the sources leave out

Stainless steel grade, columbium alloy grade, injector and valve materials, gimbal ring material and bolt or seal materials are not stated. The engine was refurbished for Orion; no source lists replaced materials beyond harnesses, sensors, heater and valve seals.

Where this comes from

5 pages from 3 websites

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Collected from public pages and documents, checked 4 Nov 2026.

Published · Updated