{
  "id": "spacex-merlin-1d",
  "title": "Merlin 1D engine",
  "maker": "SpaceX",
  "maker_type": "Commercial",
  "kind": "mission",
  "category": "engines",
  "page": "https://spacemushroom.com/space-products/spacex-merlin-1d/",
  "website": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
  "summary": "SpaceX’s gas-generator LOX/kerosene engine for Falcon 9 and Falcon Heavy; SpaceX states a milled copper-alloy chamber liner and a pintle injector, and the vacuum version uses a niobium-alloy nozzle.",
  "application": "Nine Merlin 1D engines lift the Falcon 9 first stage, which SpaceX lands and reuses. The engines launch NASA crew and cargo to the International Space Station and commercial satellites to orbit.",
  "story": {
    "headline": "Merlin 1D is the kerosene-burning engine that lifts SpaceX's Falcon 9 and Falcon Heavy rockets.",
    "intro": [
      "SpaceX designs and builds the Merlin 1D for its Falcon rockets. It burns kerosene with liquid oxygen, and each sea-level engine pushes with 845 kilonewtons (190,000 pounds of force). Nine of them lift a Falcon 9 first stage, and SpaceX lands and reuses that stage. Twenty-seven lift a Falcon Heavy. A vacuum version powers the second stage.",
      "Milled copper alloy lines the chamber and the nozzle and gives a large safety margin against heat. The injector sprays the propellants into the chamber. It is a pintle design, first used in the Apollo-era Lunar Module landing engine. On the vacuum version, the bell-shaped nozzle is made of niobium sheet alloy."
    ],
    "built": [
      {
        "title": "Chamber and nozzle",
        "text": "The thrust chamber and nozzle are regeneratively cooled: propellant flows through their walls and carries heat away. The liner is milled copper alloy. On the vacuum version, a thin niobium nozzle extension is radiatively cooled, so it gives off heat as radiation instead.",
        "parts": [
          "Chamber and nozzle liner",
          "Radiatively cooled nozzle extension"
        ]
      },
      {
        "title": "Injector and turbopump",
        "text": "SpaceX says the pintle injector gives the engine inherent combustion stability. The turbopump, the machine that forces propellant into the engine, has a single shaft joining the oxygen pump, the fuel pump and the turbine, and it spins at roughly 30,000 rpm. A gas generator burns a small flow of propellant to drive that turbine.",
        "parts": [
          "Pintle injector",
          "Turbopump (single shaft for LOX pump, fuel pump and turbine)",
          "Gas generator (open cycle)"
        ]
      },
      {
        "title": "Steering and start-up",
        "text": "The whole engine swivels on a gimbal to steer the rocket, and on the first stage the actuators run on high-pressure kerosene, so no separate hydraulic system is needed. TEA-TEB, a fluid that ignites by itself, starts the engine. Triple-redundant computers control each engine.",
        "parts": [
          "Engine gimbal (pitch and yaw)",
          "Thrust-vector-control actuators driven by high-pressure RP-1",
          "TEA-TEB pyrophoric igniter",
          "Engine computers (triple-redundant)"
        ]
      },
      {
        "title": "Checks before liftoff",
        "text": "Falcon 9 chills its engines before launch. After ignition the first stage stays on the pad until automated monitors confirm that each engine is running normally. If anything is off, the engines shut down on their own, and in flight the vehicle software can shut down a failing engine.",
        "parts": [
          "Engine chill-down before launch",
          "Pad hold-down and automated engine monitors",
          "Autonomous safe shutdown",
          "Engine-out vehicle management software"
        ]
      },
      {
        "title": "Vacuum version",
        "text": "The Merlin Vacuum powers the second stage and delivers 981 kilonewtons in vacuum. Its nozzle is fixed rather than folding out, and two redundant igniters let it restart in flight. A later version has a shorter nozzle extension that gives up some performance and uses less material.",
        "parts": [
          "Merlin Vacuum variant (MVac, second stage)",
          "Shorter Merlin Vacuum nozzle extension (later variant)",
          "Dual redundant igniters (Merlin Vacuum)"
        ]
      }
    ],
    "materials": [
      {
        "name": "Copper alloy",
        "mid": "copper-alloy",
        "where": "The milled liner of the thrust chamber and nozzle. SpaceX does not name the grade."
      },
      {
        "name": "Niobium alloy",
        "mid": "niobium-alloy",
        "where": "Thin sheet forming the bell-shaped, radiatively cooled nozzle extension of the Merlin Vacuum."
      }
    ],
    "connections": "The Merlin 1C powered the first Falcon 9, and the Merlin 1D follows it. The original Merlin 1A drew on NASA's Fastrac engine. The 1D's pintle injector was borrowed from the Apollo Lunar Module's landing engine, and its gas generator is like the one in Rocketdyne's F-1. A Falcon 9 first stage carries nine Merlin 1Ds and a Falcon Heavy 27, and each rocket adds one Merlin Vacuum. Barber-Nichols built the turbopump of an earlier Merlin.",
    "unknown": "SpaceX says little about what the engine is made of. It does not name the copper alloy, the grade of the niobium, or the metals in the turbopump, injector, manifolds and valves. Nor does it name any outside supplier for the current engine.",
    "facts": [
      {
        "label": "Sea-level thrust",
        "value": "845 kN (190,000 lbf)"
      },
      {
        "label": "Merlin Vacuum thrust",
        "value": "981 kN (220,500 lbf)"
      },
      {
        "label": "Propellants",
        "value": "Kerosene and liquid oxygen"
      },
      {
        "label": "Cycle",
        "value": "Gas generator"
      },
      {
        "label": "Engines per rocket",
        "value": "9 on Falcon 9 first stage; 27 on Falcon Heavy"
      },
      {
        "label": "Development and first flight",
        "value": "developed 2011 to 2012, first flight 2013"
      }
    ]
  },
  "specifications": [
    {
      "label": "Sea-level thrust",
      "value": "845 kN (190,000 lbf)",
      "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
      "quote": "845 kN (190,000 lbf) of thrust at sea level"
    },
    {
      "label": "Cycle",
      "value": "Gas generator",
      "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
      "quote": "The engine uses a gas generator cycle instead of the more complex staged combustion cycle."
    },
    {
      "label": "Propellants",
      "value": "Kerosene and liquid oxygen",
      "source_url": "https://www.nasa.gov/missions/station/nasa-marshall-spacex-team-celebrates-engines-of-success/",
      "quote": "uses kerosene and liquid oxygen as fuel"
    },
    {
      "label": "Engines per vehicle",
      "value": "9 on Falcon 9 first stage; 27 on Falcon Heavy",
      "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
      "quote": "each booster and the core has nine Merlin 1D (M1D) engines"
    },
    {
      "label": "Vacuum thrust of the Merlin Vacuum (second stage)",
      "value": "981 kN (220,500 lbf)",
      "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
      "quote": "981 kN (Vacuum) (220,500 lbf)"
    },
    {
      "label": "Throttle range, first stage (sea level)",
      "value": "190,000 lbf to 108,300 lbf",
      "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
      "quote": "Yes (190,000 lbf to 108,300 lbf sea level)"
    },
    {
      "label": "Throttle range, second stage",
      "value": "220,500 lbf to 140,679 lbf",
      "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
      "quote": "Yes (220,500 lbf to 140,679 lbf)"
    },
    {
      "label": "Restart capability",
      "value": "yes on both stages",
      "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
      "quote": "Restart capability Yes Yes"
    },
    {
      "label": "Engines flown per launch",
      "value": "10 on Falcon 9, 28 on Falcon Heavy",
      "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
      "quote": "fly 10 Merlin engines (Falcon 9) or 28 engines (Falcon Heavy) on every launch"
    },
    {
      "label": "Thrust-to-weight claim",
      "value": "highest of any boost engine ever made (SpaceX claim)",
      "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
      "quote": "which has the highest thrust-to-weight ratio of any boost engine ever made"
    },
    {
      "label": "Turbopump shaft speed",
      "value": "about 30,000 rpm",
      "source_url": "https://www.nasa.gov/missions/station/nasa-marshall-spacex-team-celebrates-engines-of-success/",
      "quote": "The rotating shaft in Merlin's turbopump spins at roughly 30,000 rpm."
    },
    {
      "label": "Chamber pressure",
      "value": "9.7 MPa (1,410 psi)",
      "source_url": "https://en.wikipedia.org/wiki/Merlin_(rocket_engine_family)",
      "quote": "chamber pressure in the 'sweet spot' of 9.7 MPa (1,410 psi)"
    },
    {
      "label": "Development and first flight",
      "value": "developed 2011 to 2012, first flight 2013",
      "source_url": "https://en.wikipedia.org/wiki/Merlin_(rocket_engine_family)",
      "quote": "The Merlin 1D engine was developed by SpaceX between 2011 and 2012, with first flight in 2013."
    },
    {
      "label": "First flight of the first-generation Merlin Vacuum (Merlin 1C-based)",
      "value": "4 June 2010, first Falcon 9 flight (second stage)",
      "source_url": "https://en.wikipedia.org/wiki/Merlin_(rocket_engine_family)",
      "quote": "It was flown on the second stage for the inaugural Falcon 9 flight on June 4, 2010."
    },
    {
      "label": "Propellants (NASA description)",
      "value": "kerosene and liquid oxygen",
      "source_url": "https://www.nasa.gov/missions/station/nasa-marshall-spacex-team-celebrates-engines-of-success/",
      "quote": "the Merlin 1D first stage engine uses kerosene and liquid oxygen as fuel"
    }
  ],
  "features": [
    {
      "text": "Pintle injector for combustion stability",
      "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
      "quote": "A pintle injector provides inherent combustion stability."
    },
    {
      "text": "Pintle design borrowed from the Apollo lunar module landing engine",
      "source_url": "https://www.nasa.gov/missions/station/nasa-marshall-spacex-team-celebrates-engines-of-success/",
      "quote": "incorporates a pintle injector first used in the Apollo-era Lunar Module landing engine"
    },
    {
      "text": "Fixed vacuum nozzle on the second-stage Merlin Vacuum",
      "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
      "quote": "The second stage Merlin Vacuum engine uses a fixed, non-deploying expansion nozzle"
    }
  ],
  "parts": [
    {
      "assembly": "Thrust chamber and nozzle",
      "parts": [
        {
          "part": "Chamber and nozzle liner",
          "material": "copper alloy (grade not stated)",
          "form": "milled liner, regeneratively cooled",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "use a milled copper alloy liner that provides large heat flux margins",
          "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
          "profile": null,
          "mid": "copper-alloy"
        },
        {
          "part": "Outer jacket / structural shell",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The regeneratively cooled nozzle and thrust chamber use a milled copper alloy liner",
          "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
          "profile": null,
          "mid": null
        }
      ]
    },
    {
      "assembly": "Injector",
      "parts": [
        {
          "part": "Pintle injector",
          "material": null,
          "form": "pintle",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "A pintle injector provides inherent combustion stability.",
          "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
          "profile": null,
          "mid": null
        }
      ]
    },
    {
      "assembly": "Turbopump",
      "parts": [
        {
          "part": "Turbopump (single shaft for LOX pump, fuel pump and turbine)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The engine features a reliable turbopump design with a single shaft for the liquid oxygen pump, the fuel pump, and the turbine.",
          "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
          "profile": null,
          "mid": null
        }
      ]
    },
    {
      "assembly": "Vacuum nozzle extension (Merlin Vacuum, upper stage)",
      "parts": [
        {
          "part": "Radiatively cooled nozzle extension",
          "material": "niobium sheet alloy",
          "form": "bell-shaped, thin sheet",
          "finish": null,
          "standard": null,
          "hardware_ref": "Merlin Vacuum engine, second stage",
          "quote": "The bell shaped Merlin Vacuum nozzle is made out of niobium sheet alloy",
          "source_url": "https://www.universetoday.com/articles/spacex-shoots-for-dec-8-launch-of-falcon-9",
          "profile": null,
          "mid": "niobium-alloy"
        }
      ]
    },
    {
      "assembly": "Engine variants",
      "parts": [
        {
          "part": "Merlin 1D sea-level variant (M1D, first stage)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": "Supplier: SpaceX",
          "quote": "Nine SpaceX M1D engines power the Falcon 9 first stage with up to 845 kN (190,000 lbf) thrust per engine at sea level",
          "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
          "profile": null,
          "mid": null,
          "function": "nine per Falcon 9 first stage, 27 on Falcon Heavy",
          "specs": [
            {
              "label": "Sea-level thrust",
              "value": "845 kN (190,000 lbf)",
              "quote": "up to 845 kN (190,000 lbf) thrust per engine at sea level",
              "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf"
            },
            {
              "label": "Throttle range (sea level)",
              "value": "190,000 lbf to 108,300 lbf",
              "quote": "Yes (190,000 lbf to 108,300 lbf sea level)",
              "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf"
            },
            {
              "label": "Engine designer",
              "value": "SpaceX",
              "quote": "Engine designer SpaceX",
              "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf"
            },
            {
              "label": "Engine manufacturer",
              "value": "SpaceX",
              "quote": "Engine manufacturer SpaceX",
              "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf"
            }
          ]
        },
        {
          "part": "Merlin Vacuum variant (MVac, second stage)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": "Supplier: SpaceX",
          "quote": "A single Merlin Vacuum (MVac) engine powers the second stage, using a fixed 165:1 expansion nozzle.",
          "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
          "profile": null,
          "mid": null,
          "function": "single upper-stage engine with a fixed vacuum nozzle",
          "specs": [
            {
              "label": "Vacuum thrust",
              "value": "981 kN (220,500 lbf)",
              "quote": "981 kN (Vacuum) (220,500 lbf)",
              "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf"
            },
            {
              "label": "Throttle range",
              "value": "220,500 lbf to 140,679 lbf",
              "quote": "Yes (220,500 lbf to 140,679 lbf)",
              "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf"
            },
            {
              "label": "Nozzle type",
              "value": "fixed, non-deploying",
              "quote": "uses a fixed, non-deploying expansion nozzle, eliminating potential failure modes in nozzle extension",
              "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf"
            }
          ]
        },
        {
          "part": "Shorter Merlin Vacuum nozzle extension (later variant)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "This new nozzle extension is shorter and, as a result, decreases both performance and material usage.",
          "source_url": "https://en.wikipedia.org/wiki/Merlin_(rocket_engine_family)",
          "profile": null,
          "mid": null,
          "function": "trades some performance for less material"
        }
      ]
    },
    {
      "assembly": "Turbomachinery",
      "parts": [
        {
          "part": "Gas generator (open cycle)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The engine uses a gas generator cycle instead of the more complex staged combustion cycle.",
          "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
          "profile": null,
          "mid": null,
          "function": "burns a small flow of propellant to drive the turbine instead of staged combustion",
          "specs": [
            {
              "label": "Gas generator type",
              "value": "fuel-rich, open cycle, similar to the Rocketdyne F-1",
              "quote": "a fuel-rich open-cycle gas generator similar to that used in the Apollo-era Rocketdyne F-1 engine",
              "source_url": "https://en.wikipedia.org/wiki/Merlin_(rocket_engine_family)"
            }
          ]
        },
        {
          "part": "Gimballing turbine exhaust duct (Falcon 9 v1.0 Merlin Vacuum)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "Turbine exhaust duct (gimbal)",
          "source_url": "https://www.spaceflightnow.com/falcon9/001/f9guide.pdf",
          "profile": null,
          "mid": null,
          "function": "provided second-stage roll control on the first Falcon 9 version"
        }
      ]
    },
    {
      "assembly": "Control and actuation",
      "parts": [
        {
          "part": "Engine gimbal (pitch and yaw)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "Pitch, yaw Gimbaled engines Gimbaled engine/nitrogen gas thrusters",
          "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
          "profile": null,
          "mid": null,
          "function": "steers the thrust vector"
        },
        {
          "part": "Thrust-vector-control actuators driven by high-pressure RP-1",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "the first stage thrust vector control system pulls from the high-pressure rocket-grade kerosene system",
          "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
          "profile": null,
          "mid": null,
          "function": "no separate hydraulic fluid system"
        },
        {
          "part": "Engine computers (triple-redundant)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "SpaceX uses a triple-redundant design in the Merlin engine computers.",
          "source_url": "https://en.wikipedia.org/wiki/Merlin_(rocket_engine_family)",
          "profile": null,
          "mid": null,
          "function": "control each engine"
        }
      ]
    },
    {
      "assembly": "Ignition",
      "parts": [
        {
          "part": "TEA-TEB pyrophoric igniter",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "SpaceX's Merlin engines use pyrophoric igniters with a hypergolic fluid called triethylaluminum-triethylborane, or TEA-TEB.",
          "source_url": "https://spaceflightnow.com/falcon9/007/131122engine/",
          "profile": null,
          "mid": null,
          "function": "starts the engine with a hypergolic fluid"
        },
        {
          "part": "Dual redundant igniters (Merlin Vacuum)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "the engine contains dual redundant triethylaluminum-triethylborane (TEA-TEB) pyrophoric igniters",
          "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
          "profile": null,
          "mid": null,
          "function": "added reliability for in-flight restart"
        }
      ]
    },
    {
      "assembly": "Installation",
      "parts": [
        {
          "part": "Octaweb engine mount",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The booster stage has 9 engines, arranged in a configuration that SpaceX calls Octaweb.",
          "source_url": "https://en.wikipedia.org/wiki/Falcon_9",
          "profile": null,
          "mid": null,
          "function": "arranges the nine first-stage engines and carries their thrust"
        },
        {
          "part": "Individual engine bay",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "each engine is housed within its own metal bay to isolate it from neighboring engines",
          "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
          "profile": null,
          "mid": null,
          "function": "each engine sits in its own metal bay"
        }
      ]
    },
    {
      "assembly": "Engine health and start",
      "parts": [
        {
          "part": "Engine controller (ignition sequence)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "Engine controller commands engine ignition sequence to start",
          "source_url": "https://www.nasa.gov/wp-content/uploads/2015/10/commercial_crew_press_kit_2.pdf",
          "profile": null,
          "mid": null,
          "function": "commands the engine start sequence"
        },
        {
          "part": "Engine chill-down before launch",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "Falcon 9 begins engine chill prior to launch",
          "source_url": "https://www.nasa.gov/wp-content/uploads/2015/10/commercial_crew_press_kit_2.pdf",
          "profile": null,
          "mid": null,
          "function": "chills the engines ahead of ignition"
        },
        {
          "part": "Pad hold-down and automated engine monitors",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "the first stage is held on the ground after engine ignition while automated monitors confirm nominal engine operation",
          "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
          "profile": null,
          "mid": null,
          "function": "first stage is held after ignition until engines are verified"
        },
        {
          "part": "Autonomous safe shutdown",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "An autonomous safe shutdown is performed if any off-nominal condition is detected.",
          "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
          "profile": null,
          "mid": null,
          "function": "stops the engines if any off-nominal condition is detected"
        },
        {
          "part": "Engine-out vehicle management software",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "System-level vehicle management software controls the shutdown of engines in response to off-nominal engine indications",
          "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf",
          "profile": null,
          "mid": null,
          "function": "shuts down failing engines in flight"
        }
      ]
    },
    {
      "assembly": "Test infrastructure",
      "parts": [
        {
          "part": "SpaceX engine test stands, McGregor, Texas",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "spent months reviewing data from Merlin engine tests performed at the SpaceX test facility in McGregor, Texas",
          "source_url": "https://www.nasa.gov/missions/station/nasa-marshall-spacex-team-celebrates-engines-of-success/",
          "profile": null,
          "mid": null,
          "function": "acceptance and qualification testing of Merlin engines"
        }
      ]
    }
  ],
  "materials": [
    {
      "id": "copper-alloy",
      "name": "copper alloy (grade not stated)",
      "material_page": null
    },
    {
      "id": "niobium-alloy",
      "name": "niobium sheet alloy",
      "material_page": null
    }
  ],
  "standards": [],
  "relations": [
    {
      "type": "part_of",
      "target": "Falcon 9",
      "target_slug": "spacex-falcon-9",
      "note": "9 Merlin 1D on the first stage",
      "quote": "Nine SpaceX M1D engines power the Falcon 9 first stage",
      "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf"
    },
    {
      "type": "part_of",
      "target": "Falcon 9 second stage",
      "target_slug": "spacex-falcon-9",
      "note": "single Merlin Vacuum (MVac) with a fixed 165:1 nozzle",
      "quote": "A single Merlin Vacuum (MVac) engine powers the second stage",
      "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf"
    },
    {
      "type": "part_of",
      "target": "Falcon Heavy",
      "target_slug": "spacex-falcon-heavy",
      "note": "27 Merlin 1D on the first stage: nine on the centre core and nine on each of the two side boosters",
      "quote": "Twenty-seven SpaceX Merlin engines power the Falcon Heavy first stage boosters and core",
      "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf"
    },
    {
      "type": "part_of",
      "target": "Falcon Heavy second stage",
      "target_slug": "spacex-falcon-heavy",
      "note": "single Merlin Vacuum on the upper stage shared with Falcon 9",
      "quote": "The upper stage is powered by a single Merlin 1D engine modified for vacuum operation",
      "source_url": "https://en.wikipedia.org/wiki/Falcon_Heavy"
    },
    {
      "type": "heritage_of",
      "target": "Apollo Lunar Module",
      "target_slug": "grumman-apollo-lunar-module",
      "note": "pintle injector first used in the Lunar Module landing engine",
      "quote": "incorporates a pintle injector first used in the Apollo-era Lunar Module landing engine",
      "source_url": "https://www.nasa.gov/missions/station/nasa-marshall-spacex-team-celebrates-engines-of-success/"
    },
    {
      "type": "heritage_of",
      "target": "F-1 engine (Rocketdyne)",
      "target_slug": "nasa-rocketdyne-f-1",
      "note": "gas generator similar to the F-1's",
      "quote": "a fuel-rich open-cycle gas generator similar to that used in the Apollo-era Rocketdyne F-1 engine",
      "source_url": "https://en.wikipedia.org/wiki/Merlin_(rocket_engine_family)"
    },
    {
      "type": "heritage_of",
      "target": "Fastrac engine (NASA Marshall)",
      "target_slug": null,
      "note": "SpaceX drew on the Fastrac design and technology for the original Merlin 1A",
      "quote": "SpaceX leveraged much of the design and technology to aid development of its original Merlin 1A engine.",
      "source_url": "https://www.nasa.gov/missions/station/nasa-marshall-spacex-team-celebrates-engines-of-success/"
    },
    {
      "type": "successor_of",
      "target": "Merlin 1C",
      "target_slug": null,
      "note": "Merlin 1C powered Falcon 9 v1.0: nine first-stage engines plus one vacuum engine",
      "quote": "Falcon 9 makes use of ten Merlin 1C engines on each vehicle (nine on the first stage, one on the second stage)",
      "source_url": "https://www.spaceflightnow.com/falcon9/001/f9guide.pdf"
    },
    {
      "type": "supplied_by",
      "target": "Barber-Nichols",
      "target_slug": null,
      "note": "designed and produced the turbopump of the earlier Merlin (more than 100,000 lbf sea level class); the source does not say who builds the 1D turbopump",
      "quote": "BN designed and produced the Merlin Turbopump for the SpaceX Falcon Launch Vehicle.",
      "source_url": "https://www.barber-nichols.com/products/rocket-engine-turbopumps"
    },
    {
      "type": "supplied_by",
      "target": "SpaceX",
      "target_slug": null,
      "note": "designs and manufactures its own Merlin engines (first and second stage)",
      "quote": "Engine manufacturer SpaceX",
      "source_url": "https://www.spacex.com/assets/media/falcon-users-guide-2025-05-09.pdf"
    }
  ],
  "not_published": "No turbopump, injector, manifold, jacket or valve materials stated. No standards or grades. More detail: SpaceX publishes no Merlin bill of materials: turbopump housings, gas generator, manifolds, valves, igniter hardware and the actuator hardware have no stated alloys. No supplier is named for the Merlin 1D beyond SpaceX itself; Barber-Nichols is named only for the earlier Merlin turbopump (more than 100,000 lbf class). The hydraulic actuator, gimbal and engine-computer hardware is described only in general terms. The 2025 user guide quotes the engine designation 'M1D' and 'MVac'; the exact first-flight date of the Merlin 1D (Falcon 9 v1.1, 2013) comes from Wikipedia and the Spaceflight Now article, not from a SpaceX document. Quotes from the Falcon User's Guides (2025 and 2009) were machine-checked against the PDF text; quotes from NASA web pages, Spaceflight Now, Barber-Nichols and Wikipedia came through a text extractor and were not machine-checked. The chamber-pressure figure is a Wikipedia statement that cites Aviation Week; the F-1 gas-generator similarity is a Wikipedia statement that cites a textbook. More detail: SpaceX publishes no Merlin bill of materials: turbopump housings, gas generator, manifolds, valves, igniter hardware and the actuator hardware have no stated alloys. No supplier is named for the Merlin 1D beyond SpaceX itself; Barber-Nichols is named only for the earlier Merlin turbopump (more than 100,000 lbf class). The hydraulic actuator, gimbal and engine-computer hardware is described only in general terms. The 2025 user guide quotes the engine designation 'M1D' and 'MVac'; the exact first-flight date of the Merlin 1D (Falcon 9 v1.1, 2013) comes from Wikipedia and the Spaceflight Now article, not from a SpaceX document. Quotes from the Falcon User's Guides (2025 and 2009) were machine-checked against the PDF text; quotes from NASA web pages, Spaceflight Now, Barber-Nichols and Wikipedia came through a text extractor and were re-checked in a second fetch pass but not against a saved copy of the page. The chamber-pressure figure is a Wikipedia statement that cites Aviation Week; the F-1 gas-generator similarity is a Wikipedia statement that cites a textbook.",
  "depth": "partial",
  "photos": [
    {
      "file": "products/context/spacex-merlin-1d-1.jpg",
      "alt": "A Merlin 1D engine firing on a test stand in Texas",
      "long": "A Merlin 1D engine firing on a test stand in Texas",
      "kind": "product",
      "credit": "SpaceX | http://www.spacex.com/media-gallery/detail/1661/172; see also http://www.spacex.com/news/2013/03/26/merlin-engines",
      "license": "CC0",
      "page_url": "https://commons.wikimedia.org/wiki/File:SpaceX_Testing_Merlin_1D_Engine_In_Texas.jpg"
    },
    {
      "file": "products/context/spacex-merlin-1d-2.jpg",
      "alt": "Two Merlin engines mounted on the dual test stand",
      "long": "Two Merlin engines mounted on the dual test stand",
      "kind": "product",
      "credit": "SpaceX | http://www.spacex.com/media-gallery/detail/1661/1081",
      "license": "CC0",
      "page_url": "https://commons.wikimedia.org/wiki/File:Merlin_Engine_Dual_Test_Stand.jpg"
    },
    {
      "file": "products/context/spacex-merlin-1d-3.jpg",
      "alt": "Merlin 1D engines and octaweb thrust structure on the factory floor, flight hardware with a Do Not Touch sign",
      "long": "Merlin 1D engines and octaweb thrust structure on the factory floor, flight hardware with a Do Not Touch sign",
      "kind": "product",
      "credit": "Steve Jurvetson | https://www.flickr.com/photos/jurvetson/8975298066/",
      "license": "CC BY 2.0",
      "page_url": "https://commons.wikimedia.org/wiki/File:Merlin_1D_engines_and_octaweb_harness.jpg"
    }
  ],
  "context": {
    "size": [],
    "mass": [],
    "orbit": []
  },
  "licence": "Product data CC BY 4.0, cite Space Mushroom. Photos keep their own licences, given per photo.",
  "mcp": "https://spacemushroom.com/mcp"
}