{
  "id": "nasa-jwst",
  "title": "James Webb Space Telescope",
  "maker": "NASA (with ESA and CSA; prime contractor Northrop Grumman)",
  "maker_type": "Space agency",
  "kind": "mission",
  "category": "observatories",
  "page": "https://spacemushroom.com/space-products/nasa-jwst/",
  "website": "https://webb.nasa.gov/content/about/faqs/facts.html",
  "summary": "NASA infrared space observatory with an 18-segment gold-coated beryllium primary mirror and a five-layer Kapton sunshield.",
  "application": "The largest space telescope ever launched, observing in the infrared from the Sun-Earth L2 point. Its gold-coated beryllium mirror stays shape-stable at cryogenic temperature, and a five-layer Kapton sunshield keeps the instruments below 50 K. It studies early galaxies, star and planet formation and exoplanet atmospheres.",
  "story": {
    "headline": "Webb is NASA's infrared space telescope, and the largest one ever launched.",
    "intro": [
      "The James Webb Space Telescope looks at the sky in infrared light, which our eyes cannot see. NASA built it with the European and Canadian space agencies, and Northrop Grumman was the main contractor. It studies early galaxies, how stars and planets form, and the atmospheres of planets around other stars.",
      "Its main mirror is 6.5 m across and made of 18 hexagonal segments, each a piece of beryllium with a thin coat of gold. A five-layer sunshield blocks the light and heat of the Sun, Earth and Moon. That keeps the instruments below 50 kelvin, far below freezing."
    ],
    "built": [
      {
        "title": "The mirror",
        "text": "The 18 segments are made of beryllium, which gives them strength without much weight. One segment weighs 20.1 kg. A gold coating, 100 nanometres (billionths of a metre) thick, covers 25 square metres of mirror and takes about 48 g of gold.",
        "parts": [
          "Primary mirror segment substrate",
          "Primary mirror coating"
        ]
      },
      {
        "title": "The sunshield",
        "text": "The shield measures 21.197 m by 14.162 m and has five membranes of Kapton E plastic film, each thinner than a human hair. Every layer is coated with aluminium. On layers 1 and 2, the sun-facing side also carries a doped silicon coating, which gives them a lavender-pink colour.",
        "parts": [
          "Sunshield membrane layers (5)",
          "Sunshield layer coating (all 5 layers)",
          "Sunshield Layers 1 and 2 sun-facing coating"
        ]
      },
      {
        "title": "The backplane",
        "text": "The backplane is the structure that holds the mirror segments steady at cryogenic, or extremely low, temperatures. It must carry more than 2,400 kg. It is made of advanced graphite composite, joined to titanium and invar fittings.",
        "parts": [
          "Backplane structure",
          "Backplane fittings and interfaces"
        ]
      },
      {
        "title": "Engines and fuel",
        "text": "The spacecraft's MRE-1 engines run on hydrazine alone. The SCAT thrusters burn hydrazine with dinitrogen tetroxide as the oxidiser, the chemical that lets the fuel burn.",
        "parts": [
          "Monopropellant engine fuel",
          "SCAT thruster oxidizer"
        ]
      }
    ],
    "materials": [
      {
        "name": "Beryllium",
        "mid": "beryllium",
        "where": "The 18 hexagonal segments of the primary mirror. It gives them the strength they need at light weight."
      },
      {
        "name": "Gold",
        "mid": "gold",
        "where": "A very thin coating, 100 nm thick, on each mirror segment."
      },
      {
        "name": "Kapton E polyimide film",
        "mid": "kapton-e",
        "where": "The five membrane layers of the sunshield. Each one is thinner than a human hair."
      },
      {
        "name": "Aluminium",
        "mid": "aluminium",
        "where": "A coating on all five sunshield layers."
      },
      {
        "name": "Doped silicon",
        "mid": "doped-silicon",
        "where": "The sun-facing coating on sunshield layers 1 and 2. It gives them their lavender-pink colour."
      },
      {
        "name": "Advanced graphite composite",
        "mid": "graphite-composite",
        "where": "The backplane structure that holds the mirror segments steady."
      }
    ],
    "connections": "Webb is a joint project of NASA, the European Space Agency and the Canadian Space Agency, with Northrop Grumman as main contractor. An Ariane 5 ECA rocket launched it on 25 December 2021. It now orbits a point called Sun-Earth L2, 1.5 million km from Earth. Its propulsion comes from MRE-1 engines and SCAT thrusters, and its sunshield film is DuPont's Kapton E.",
    "unknown": "A few details are not public. The makers do not name the grade of beryllium in the mirror. The thickness of each sunshield layer, the fibre and resin in the backplane, and the materials of the spacecraft body, its insulation and its solar cells are also missing. It is not clear who made the mirror segments.",
    "facts": [
      {
        "label": "Mirror diameter",
        "value": "6.5 m"
      },
      {
        "label": "Sunshield size",
        "value": "21.197 m x 14.162 m"
      },
      {
        "label": "Gold used",
        "value": "About 48 g on 25 m2"
      },
      {
        "label": "Operating temperature",
        "value": "Under 50 K"
      },
      {
        "label": "Orbit",
        "value": "1.5 million km from Earth, Sun-Earth L2"
      },
      {
        "label": "Launch",
        "value": "25 December 2021, Ariane 5 ECA"
      }
    ]
  },
  "specifications": [
    {
      "label": "Launch date",
      "value": "25 December 2021, Ariane 5 ECA",
      "source_url": "https://webb.nasa.gov/content/about/faqs/facts.html",
      "quote": "December 25, 2021 07:20am EST"
    },
    {
      "label": "Total payload mass",
      "value": "Approx 6200 kg including observatory, consumables and launch adaptor",
      "source_url": "https://webb.nasa.gov/content/about/faqs/facts.html",
      "quote": "Approx 6200 kg, including observatory, on-orbit consumables and launch vehicle adaptor"
    },
    {
      "label": "Primary mirror diameter",
      "value": "6.5 m",
      "source_url": "https://webb.nasa.gov/content/about/faqs/facts.html",
      "quote": "6.5 m (21.3 ft) approximately"
    },
    {
      "label": "Primary mirror mass",
      "value": "705 kg",
      "source_url": "https://webb.nasa.gov/content/about/faqs/facts.html",
      "quote": "Mass of Primary Mirror 705 kg"
    },
    {
      "label": "Mirror segment mass",
      "value": "20.1 kg per beryllium segment",
      "source_url": "https://webb.nasa.gov/content/about/faqs/facts.html",
      "quote": "20.1 kg for a single beryllium mirror"
    },
    {
      "label": "Sunshield size",
      "value": "21.197 m x 14.162 m",
      "source_url": "https://webb.nasa.gov/content/about/faqs/facts.html",
      "quote": "21.197 m x 14.162 m (69.5 ft x 46.5 ft)"
    },
    {
      "label": "Gold coating thickness",
      "value": "100 nm",
      "source_url": "https://webb.nasa.gov/content/about/faqs/facts.html",
      "quote": "Thickness of gold coating = 100 x 10 -9 meters"
    },
    {
      "label": "Gold used",
      "value": "About 48 g on 25 m2",
      "source_url": "https://webb.nasa.gov/content/about/faqs/facts.html",
      "quote": "the coating is calculated to use 48.25g of gold"
    },
    {
      "label": "Orbit",
      "value": "1.5 million km from Earth, Sun-Earth L2",
      "source_url": "https://webb.nasa.gov/content/about/faqs/facts.html",
      "quote": "1.5 million km from Earth orbiting the L2 Point"
    },
    {
      "label": "Operating temperature",
      "value": "Under 50 K",
      "source_url": "https://webb.nasa.gov/content/about/faqs/facts.html",
      "quote": "Operating Temperature under 50 K"
    },
    {
      "label": "Primary mirror segment assembly mass",
      "value": "about 40 kg with its actuator",
      "source_url": "https://science.nasa.gov/mission/webb/webbs-mirrors/",
      "quote": "(A full primary mirror segment assembly including its actuator is about 40 kg.)"
    },
    {
      "label": "Unobscured collecting area",
      "value": "25.4 m2",
      "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-telescope",
      "quote": "The unobscured collecting area of the primary mirror is 25.4 m2."
    },
    {
      "label": "Sunshield thermal drop",
      "value": "intercepts over 200,000 W, passes about 1 W",
      "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-observatory-overview",
      "quote": "a sun shield that intercepts over 200,000 W of radiant energy from the Sun and transmits only about 1 W to the OTE and ISIM"
    },
    {
      "label": "Cryogenic instrument module detector temperature",
      "value": "39 K",
      "source_url": "https://science.nasa.gov/mission/webb/integrated-science-instrument-module-isim/",
      "quote": "This chills the detectors down to 39 K"
    },
    {
      "label": "Propellant life",
      "value": "enough for more than 20 years",
      "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-spacecraft-bus",
      "quote": "The observatory carries enough propellant for more than 20 years of science operations."
    },
    {
      "label": "Communications",
      "value": "Ka-band 0.875, 1.75 or 3.5 Mbytes/s; S-band 40 kbps real time",
      "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-spacecraft-bus/jwst-communications-subsystem",
      "quote": "The Ka-band downlink data rate has 3 selectable speeds: 0.875, 1.75, and 3.5 Mbytes/s."
    },
    {
      "label": "Downlink per contact",
      "value": "at least 229 Gbits science and 8 Gbits engineering in 4 hours",
      "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-spacecraft-bus",
      "quote": "a minimum of 229 Gbits of recorded science data and 8 Gbits of engineering data during a 4-hour contact"
    },
    {
      "label": "Launch",
      "value": "25 December 2021, 7:20 AM ET (12:20 UT), ELA-3, Kourou",
      "source_url": "https://science.nasa.gov/mission/webb/launch/",
      "quote": "On December 25, 2021, and 7:20 AM ET (12:20 UTC), the James Webb Space Telescope was launched by an ArianeSpace Ariane 5 rocket"
    },
    {
      "label": "Ariane 5 ECA core stage load",
      "value": "150 t liquid oxygen and 25 t liquid hydrogen",
      "source_url": "https://www.esa.int/Enabling_Support/Space_Transportation/Launch_vehicles/Ariane_5_ECA",
      "quote": "Liquid oxygen: 150 tonnes"
    },
    {
      "label": "NIRSpec multi-object capacity",
      "value": "about 100 objects at once",
      "source_url": "https://science.nasa.gov/mission/webb/nirspec/",
      "quote": "the NIRSpec is designed to observe 100 objects simultaneously"
    },
    {
      "label": "MIRI temperature",
      "value": "no more than 6.7 K",
      "source_url": "https://science.nasa.gov/mission/webb/cryocooler/",
      "quote": "MIRI's operates at temperatures of no more than 6.7 degrees above absolute zero"
    },
    {
      "label": "Contributing countries",
      "value": "14 countries, 29+ U.S. states",
      "source_url": "https://science.nasa.gov/mission/webb/webb-team/",
      "quote": "Thousands of skilled scientists, engineers and technicians from 14 countries"
    }
  ],
  "features": [
    {
      "text": "18 hexagonal beryllium mirror segments with a thin gold coating form the primary mirror",
      "source_url": "https://webb.nasa.gov/content/observatory/ote/mirrors/index.html",
      "quote": "Each mirror segment has a very thin coating of gold applied."
    },
    {
      "text": "Five-layer sunshield blocks heat of Sun, Earth and Moon",
      "source_url": "https://webb.nasa.gov/content/observatory/sunshield.html",
      "quote": "It shields the exposed mirrors and science instruments from the light and heat of the Sun, Earth and moon."
    },
    {
      "text": "Backplane holds the mirrors steady at cryogenic temperature",
      "source_url": "https://webb.nasa.gov/content/observatory/ote/backplane.html",
      "quote": "The backplane must carry more than 2400kg"
    }
  ],
  "parts": [
    {
      "assembly": "Primary mirror (18 segments)",
      "parts": [
        {
          "part": "Primary mirror segment substrate",
          "material": "beryllium",
          "form": "hexagonal segment",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The mirror segments are made of beryllium which gives them the required strength and light weight.",
          "source_url": "https://webb.nasa.gov/content/observatory/ote/mirrors/index.html",
          "profile": null,
          "mid": "beryllium"
        },
        {
          "part": "Primary mirror coating",
          "material": "gold",
          "form": "thin vapour-deposited coating, 100 nm",
          "finish": "gold coating",
          "standard": null,
          "hardware_ref": null,
          "quote": "Each mirror segment has a very thin coating of gold applied.",
          "source_url": "https://webb.nasa.gov/content/observatory/ote/mirrors/index.html",
          "profile": null,
          "mid": "gold"
        }
      ]
    },
    {
      "assembly": "Sunshield",
      "parts": [
        {
          "part": "Sunshield membrane layers (5)",
          "material": "Kapton E polyimide film",
          "form": "membrane, each thinner than a human hair",
          "finish": null,
          "standard": null,
          "hardware_ref": "Kapton E (DuPont)",
          "quote": "five thin layers of Kapton E with aluminum and doped-silicon coatings",
          "source_url": "https://webb.nasa.gov/content/about/faqs/facts.html",
          "profile": null,
          "mid": "kapton-e"
        },
        {
          "part": "Sunshield layer coating (all 5 layers)",
          "material": "aluminum",
          "form": "coating on membranes",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "each layer is coated with aluminum",
          "source_url": "https://webb.nasa.gov/content/observatory/sunshield.html",
          "profile": "aluminium",
          "mid": "aluminium"
        },
        {
          "part": "Sunshield Layers 1 and 2 sun-facing coating",
          "material": "doped silicon",
          "form": "coating on sun-facing side",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The \"doped silicon\" gives layers 1 and 2 there distinct lavender/pink color.",
          "source_url": "https://webb.nasa.gov/content/observatory/sunshield.html",
          "profile": null,
          "mid": "doped-silicon"
        },
        {
          "part": "Sunshield release actuators and hinge assemblies",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "about 140 release actuators, approximately 70 hinge assemblies, eight deployment motors",
          "source_url": "https://science.nasa.gov/mission/webb/webbs-sunshield/",
          "profile": null,
          "mid": null,
          "function": "about 140 release actuators and about 70 hinge assemblies"
        },
        {
          "part": "Sunshield deployment motors (8)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "eight deployment motors, about 400 pulleys and 90 cables",
          "source_url": "https://science.nasa.gov/mission/webb/webbs-sunshield/",
          "profile": null,
          "mid": null,
          "function": "motors that drive the sunshield deployment"
        },
        {
          "part": "Sunshield pulleys and tensioning cables",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "about 400 pulleys and 90 cables, and scores of bearings, springs and gears",
          "source_url": "https://science.nasa.gov/mission/webb/webbs-sunshield/",
          "profile": null,
          "mid": null,
          "function": "about 400 pulleys and 90 cables tension the five layers"
        },
        {
          "part": "Rip-stop reinforcing strips",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "reinforcing strips of membrane material are Thermal Spot Bonded to the parent membrane",
          "source_url": "https://science.nasa.gov/mission/webb/webbs-sunshield/",
          "profile": null,
          "mid": null,
          "function": "membrane strips spot-bonded in a grid so small tears cannot spread"
        },
        {
          "part": "Sunshield covers",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "Technicians preparing the sunshield and sunshield covers into their folded launch configuration.",
          "source_url": "https://science.nasa.gov/mission/webb/webbs-sunshield/",
          "profile": null,
          "mid": null,
          "function": "covers over the folded sunshield for launch"
        },
        {
          "part": "Momentum flap",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The momentum flap balances the solar pressure on the sunshield, like a trim flap in sailing.",
          "source_url": "https://science.nasa.gov/mission/webb/spacecraftoverview/",
          "profile": null,
          "mid": null,
          "function": "balances solar pressure on the sunshield; fixed on orbit"
        }
      ]
    },
    {
      "assembly": "Backplane (telescope structure)",
      "parts": [
        {
          "part": "Backplane structure",
          "material": "advanced graphite composite",
          "form": "composite structure",
          "finish": null,
          "standard": null,
          "hardware_ref": "Northrop Grumman",
          "quote": "advanced graphite composite materials mated to titanium and invar fittings and interfaces",
          "source_url": "https://webb.nasa.gov/content/observatory/ote/backplane.html",
          "profile": null,
          "mid": "graphite-composite"
        },
        {
          "part": "Backplane fittings and interfaces",
          "material": "titanium",
          "form": "fittings",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "advanced graphite composite materials mated to titanium and invar fittings and interfaces",
          "source_url": "https://webb.nasa.gov/content/observatory/ote/backplane.html",
          "profile": "titanium",
          "mid": "titanium"
        },
        {
          "part": "Backplane fittings and interfaces",
          "material": "invar",
          "form": "fittings",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "advanced graphite composite materials mated to titanium and invar fittings and interfaces",
          "source_url": "https://webb.nasa.gov/content/observatory/ote/backplane.html",
          "profile": null,
          "mid": "invar"
        }
      ]
    },
    {
      "assembly": "Spacecraft bus propulsion",
      "parts": [
        {
          "part": "Monopropellant engine fuel",
          "material": "hydrazine",
          "form": "propellant",
          "finish": null,
          "standard": null,
          "hardware_ref": "MRE-1 engines",
          "quote": "since it only uses hydrazine",
          "source_url": "https://science.nasa.gov/mission/webb/spacecraft-bus/",
          "profile": null,
          "mid": "hydrazine"
        },
        {
          "part": "SCAT thruster oxidizer",
          "material": "dinitrogen tetroxide",
          "form": "propellant",
          "finish": null,
          "standard": null,
          "hardware_ref": "SCAT thrusters",
          "quote": "They use hydrazine and dinitrogen tetroxide",
          "source_url": "https://science.nasa.gov/mission/webb/spacecraft-bus/",
          "profile": null,
          "mid": "dinitrogen-tetroxide"
        }
      ]
    },
    {
      "assembly": "Optical Telescope Element: mirrors",
      "parts": [
        {
          "part": "Primary mirror segment actuators (7 per segment)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "has actuators on the back that allow control of the 6 spatial degrees of freedom with a precision better than 10 nm",
          "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-telescope",
          "profile": null,
          "mid": null,
          "function": "six actuators position each segment; a seventh sets its radius of curvature",
          "specs": [
            {
              "label": "Radius of curvature",
              "value": "7th actuator per segment",
              "quote": "A 7th actuator on each segment controls its radius of curvature",
              "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-telescope"
            },
            {
              "label": "Count per piece",
              "value": "six actuators on each mirror piece",
              "quote": "The primary mirror segments and secondary mirror are moved by six actuators that are attached to the back of each mirror piece.",
              "source_url": "https://science.nasa.gov/mission/webb/webbs-mirrors/"
            }
          ]
        },
        {
          "part": "Beryllium mirror blanks (O-30 powder grade)",
          "material": "beryllium, grade O-30 powder",
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": "Supplier: Brush Wellman (Ohio)",
          "quote": "The particular type of beryllium used in the Webb mirrors is called O-30 and is a fine powder.",
          "source_url": "https://science.nasa.gov/mission/webb/webbs-mirrors/",
          "profile": null,
          "mid": "beryllium-o-30",
          "function": "pressed beryllium blanks, each cut to make one segment; adds the grade and supplier to the entry's beryllium substrate row",
          "specs": [
            {
              "label": "Supplier",
              "value": "Brush Wellman, Ohio",
              "quote": "The beryllium to make Webb's mirror was mined in Utah and purified at Brush Wellman in Ohio.",
              "source_url": "https://science.nasa.gov/mission/webb/webbs-mirrors/"
            },
            {
              "label": "Pressing",
              "value": "powder pressed in a stainless steel canister",
              "quote": "The powder was placed into a stainless steel canister and pressed into a flat shape.",
              "source_url": "https://science.nasa.gov/mission/webb/webbs-mirrors/"
            }
          ]
        },
        {
          "part": "Ribbed lightweight back of each segment",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": "Supplier: Axsys Technologies (Cullman, Alabama)",
          "quote": "Axsys Technologies shaped the mirror blanks into their final shape.",
          "source_url": "https://science.nasa.gov/mission/webb/webbs-mirrors/",
          "profile": null,
          "mid": null,
          "function": "material cut away to leave ribs about 1 mm thick; shaping by Axsys",
          "specs": [
            {
              "label": "Rib thickness",
              "value": "about 1 mm",
              "quote": "The ribs are only about 1 millimeter (about 1/25 of an inch) thick.",
              "source_url": "https://science.nasa.gov/mission/webb/webbs-mirrors/"
            },
            {
              "label": "Mass",
              "value": "20 kg per segment; about 40 kg with actuator",
              "quote": "A beryllium mirror segment is 20 kilograms in mass.",
              "source_url": "https://science.nasa.gov/mission/webb/webbs-mirrors/"
            }
          ]
        },
        {
          "part": "Protective silica layer over the gold coating",
          "material": "amorphous silicon dioxide (SiO2)",
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": "Supplier: Quantum Coating Incorporated",
          "quote": "A thin layer of amorphous SiO2 (glass) is deposited on top of the gold to protect it from scratches",
          "source_url": "https://science.nasa.gov/mission/webb/webbs-mirrors/",
          "profile": null,
          "mid": "silicon-dioxide-amorphous",
          "function": "thin amorphous SiO2 layer that guards the soft gold against scratches",
          "specs": [
            {
              "label": "Supplier",
              "value": "Quantum Coating Incorporated",
              "quote": "Quantum Coating Incorporated did the coatings on our telescope mirrors.",
              "source_url": "https://science.nasa.gov/mission/webb/webbs-mirrors/"
            }
          ]
        },
        {
          "part": "Secondary mirror (0.74 m, convex)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "SECONDARY MIRROR: Round 0.74 meter Secondary mirror",
          "source_url": "https://science.nasa.gov/mission/webb/optical-telescope-element-ote/",
          "profile": null,
          "mid": null,
          "function": "round mirror at the end of the booms; moved by six actuators",
          "specs": [
            {
              "label": "Shape and place",
              "value": "convex, at the end of the folding booms",
              "quote": "round convex secondary mirror that lies at the end of Webb's long folding booms",
              "source_url": "https://science.nasa.gov/mission/webb/webbs-mirrors/"
            }
          ]
        },
        {
          "part": "Tertiary mirror",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The telescope's tertiary mirror remains stationary.",
          "source_url": "https://science.nasa.gov/mission/webb/webbs-mirrors/",
          "profile": null,
          "mid": null,
          "function": "stationary mirror that removes astigmatism and flattens the focal plane"
        },
        {
          "part": "Fine steering mirror (FSM)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "A 4th flat mirror, called the fine steering mirror (FSM), is used for pointing stabilization and very small offset maneuvers",
          "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-telescope",
          "profile": null,
          "mid": null,
          "function": "flat fourth mirror for pointing stabilization and very small offset maneuvers"
        },
        {
          "part": "Aft Optics Subsystem",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "Both contained in the Aft Optics Subsystem",
          "source_url": "https://science.nasa.gov/mission/webb/optical-telescope-element-ote/",
          "profile": null,
          "mid": null,
          "function": "holds the tertiary and fine steering mirrors"
        }
      ]
    },
    {
      "assembly": "Optical Telescope Element: structure",
      "parts": [
        {
          "part": "Primary mirror wings (2)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The James Webb Space Telescope is shown with one of its two \"wings\" folded.",
          "source_url": "https://science.nasa.gov/mission/webb/webbs-mirrors/",
          "profile": null,
          "mid": null,
          "function": "two folding wings, three segments each, folded for launch"
        },
        {
          "part": "Secondary mirror support structure",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "the backplane; the secondary mirror support structure; the main backplane support fixture (BSF)",
          "source_url": "https://science.nasa.gov/mission/webb/webbs-backplane/",
          "profile": null,
          "mid": null,
          "function": "holds the secondary mirror in front of the primary"
        },
        {
          "part": "Backplane Support Fixture (BSF)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "the main backplane support fixture (BSF)",
          "source_url": "https://science.nasa.gov/mission/webb/webbs-backplane/",
          "profile": null,
          "mid": null,
          "function": "carries the backplane and the flight telescope structure"
        },
        {
          "part": "Deployable tower structure",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "the deployable tower structure that lifted the telescope off of",
          "source_url": "https://science.nasa.gov/mission/webb/webbs-backplane/",
          "profile": null,
          "mid": null,
          "function": "lifted the telescope off the spacecraft bus after launch"
        }
      ]
    },
    {
      "assembly": "Spacecraft bus: power and data",
      "parts": [
        {
          "part": "Solar array",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The solar array is always facing the sun to convert sunlight to electricity to power the Observatory.",
          "source_url": "https://science.nasa.gov/mission/webb/spacecraftoverview/",
          "profile": null,
          "mid": null,
          "function": "always faces the Sun and powers the observatory",
          "specs": [
            {
              "label": "Deployment",
              "value": "deployed about 30 minutes after launch",
              "quote": "The first deployment, the solar array, was deployed approximately 30 minutes after launch on December 25, 2021.",
              "source_url": "https://science.nasa.gov/mission/webb/faqs-full/"
            },
            {
              "label": "Capacity",
              "value": "up to 3 kW with the power conditioning and distribution",
              "quote": "provide the electrical power needed for the mission, with a capacity of up to 3 kilowatts",
              "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-spacecraft-bus"
            }
          ]
        },
        {
          "part": "Power conditioning, control and distribution systems",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The solar array, together with the power conditioning, control and distribution systems",
          "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-spacecraft-bus",
          "profile": null,
          "mid": null,
          "function": "condition and distribute the array power"
        },
        {
          "part": "Battery",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "so that Webb could start making electricity from sunshine and stop draining its battery",
          "source_url": "https://science.nasa.gov/mission/webb/faqs-full/",
          "profile": null,
          "mid": null,
          "function": "powered the observatory until the array deployed after separation"
        },
        {
          "part": "Command Telemetry Processor (CTP)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The system has a computer, the Command Telemetry Processor (CTP)",
          "source_url": "https://science.nasa.gov/mission/webb/spacecraft-bus/",
          "profile": null,
          "mid": null,
          "function": "bus computer that takes in commands and directs them to recipients"
        },
        {
          "part": "Solid State Recorder (SSR)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The spacecraft's solid state recorder (SSR) provides about 65 Gbytes",
          "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-spacecraft-bus",
          "profile": null,
          "mid": null,
          "function": "stores science and engineering data; about 65 GB"
        },
        {
          "part": "ISIM Command and Data Handling (ICDH) computer",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The ISIM Command and Data Handling (ICDH) computer creates science data files as the detectors are read out",
          "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-spacecraft-bus",
          "profile": null,
          "mid": null,
          "function": "creates science data files as detectors are read out and sends them to the recorder"
        }
      ]
    },
    {
      "assembly": "Spacecraft bus: attitude control",
      "parts": [
        {
          "part": "Sun sensors, star trackers, gyroscopes",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The ACS uses sun sensors, star trackers, and gyroscopes to sense the observatory orientation and movement, as well as reaction wheels and/or thrusters",
          "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-attitude-control-subsystem",
          "profile": null,
          "mid": null,
          "function": "sense the orientation and movement of the observatory"
        },
        {
          "part": "Star trackers (x2)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The star trackers are small telescopes that use star patterns to target the observatory.",
          "source_url": "https://science.nasa.gov/mission/webb/spacecraftoverview/",
          "profile": null,
          "mid": null,
          "function": "small telescopes that use star patterns; about 16 degree field of view",
          "specs": [
            {
              "label": "Count",
              "value": "two",
              "quote": "Control of the roll orientation about the telescope's optical axis is provided by input from the spacecraft's 2 star trackers.",
              "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-attitude-control-subsystem"
            },
            {
              "label": "Detector",
              "value": "512 x 512 pixel CCD each",
              "quote": "projected on to a 512 × 512 pixel CCD detector",
              "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-attitude-control-subsystem"
            }
          ]
        },
        {
          "part": "Gyroscopes",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "Gyroscopes are used in combination with star tracker assemblies (STAs) to estimate the orientation",
          "source_url": "https://science.nasa.gov/mission/webb/faqs-full/",
          "profile": null,
          "mid": null,
          "function": "used with star tracker assemblies to estimate orientation"
        },
        {
          "part": "Reaction wheels",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The reaction wheels provide the control torques needed to maintain attitude and pointing as well as to slew.",
          "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-attitude-control-subsystem",
          "profile": null,
          "mid": null,
          "function": "supply the control torques for pointing and slewing"
        }
      ]
    },
    {
      "assembly": "Spacecraft bus: communications",
      "parts": [
        {
          "part": "Ka-band high-gain antenna (0.6 m)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "JWST has a 0.6 m Ka-band high-gain antenna (HGA) as well as a 0.2 m S-band medium-gain antenna (MGA).",
          "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-spacecraft-bus/jwst-communications-subsystem",
          "profile": null,
          "mid": null,
          "function": "high-rate science and telemetry downlink"
        },
        {
          "part": "S-band medium-gain antenna (0.2 m)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "JWST has a 0.6 m Ka-band high-gain antenna (HGA) as well as a 0.2 m S-band medium-gain antenna (MGA).",
          "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-spacecraft-bus/jwst-communications-subsystem",
          "profile": null,
          "mid": null,
          "function": "command uplink, low-rate telemetry and ranging"
        },
        {
          "part": "HGA articulated platform",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "Both are mounted on a common articulated platform, generally referred to as the HGA platform.",
          "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-spacecraft-bus/jwst-communications-subsystem",
          "profile": null,
          "mid": null,
          "function": "common platform for both antennas; moved to keep the beam on Earth"
        }
      ]
    },
    {
      "assembly": "Spacecraft bus: propulsion",
      "parts": [
        {
          "part": "SCAT bipropellant thrusters (2 pairs)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "Webb has two pairs of them (paired for redundancy). They use hydrazine and dinitrogen tetroxide",
          "source_url": "https://science.nasa.gov/mission/webb/spacecraft-bus/",
          "profile": null,
          "mid": null,
          "function": "orbit correction and station keeping; hydrazine plus dinitrogen tetroxide",
          "specs": [
            {
              "label": "Locations",
              "value": "one pair at the bus bottom, one pair on a boom opposite the solar array",
              "quote": "One pair is located near the center of the bottom of the spacecraft bus where JWST attached to the launch vehicle.",
              "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-spacecraft-bus/jwst-propulsion"
            }
          ]
        },
        {
          "part": "MRE-1 monopropellant thrusters (x8)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "There are eight MRE-1s on Webb, and they are used for attitude control and momentum unloading of the reaction wheels.",
          "source_url": "https://science.nasa.gov/mission/webb/spacecraft-bus/",
          "profile": null,
          "mid": null,
          "function": "attitude control and unloading reaction-wheel momentum; hydrazine only"
        },
        {
          "part": "Propellant tanks (one fuel, one oxidizer) and helium pressurant",
          "material": "helium (pressurant gas)",
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "They operate in \"blowdown mode\" with one tank for each type of propellant and use gaseous helium as a pressurizing agent.",
          "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-spacecraft-bus/jwst-propulsion",
          "profile": null,
          "mid": "helium",
          "function": "blowdown tanks, one per propellant, pressurized with gaseous helium"
        }
      ]
    },
    {
      "assembly": "Spacecraft bus: thermal",
      "parts": [
        {
          "part": "Bus thermal control subsystem",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The Thermal Control Subsystem maintains the operating temperature of the spacecraft bus.",
          "source_url": "https://science.nasa.gov/mission/webb/spacecraft-bus/",
          "profile": null,
          "mid": null,
          "function": "keeps the bus at its operating temperature"
        },
        {
          "part": "Radiators released and deployed in the first week",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "other things like radiators were released and deployed",
          "source_url": "https://science.nasa.gov/mission/webb/faqs-full/",
          "profile": null,
          "mid": null,
          "function": "radiators on the observatory deployed after launch"
        }
      ]
    },
    {
      "assembly": "Integrated Science Instrument Module (ISIM)",
      "parts": [
        {
          "part": "ISIM region 1: cryogenic instrument module",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The \"region 1\" component is the cryogenic instrument module.",
          "source_url": "https://science.nasa.gov/mission/webb/integrated-science-instrument-module-isim/",
          "profile": null,
          "mid": null,
          "function": "holds the instruments and chills the detectors to 39 K"
        },
        {
          "part": "ISIM region 2: electronics compartment",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The \"region 2\" component is the ISIM Electronics Compartment",
          "source_url": "https://science.nasa.gov/mission/webb/integrated-science-instrument-module-isim/",
          "profile": null,
          "mid": null,
          "function": "mounting surfaces and ambient environment for instrument control electronics"
        },
        {
          "part": "ISIM region 3: ICDH and MIRI cryocooler electronics (in the bus)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "is the ISIM Command and Data Handling subsystem, with integral ISIM flight Software, and the MIRI cryocooler compressor and control electronics",
          "source_url": "https://science.nasa.gov/mission/webb/integrated-science-instrument-module-isim/",
          "profile": null,
          "mid": null,
          "function": "flight software computer and the cryocooler compressor and control electronics"
        }
      ]
    },
    {
      "assembly": "Instruments",
      "parts": [
        {
          "part": "NIRCam modules (x2)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": "Supplier: University of Arizona and Lockheed Martin Advanced Technology Center",
          "quote": "Each module uses a dichroic to also observe simultaneously in both the short wavelength channel",
          "source_url": "https://science.nasa.gov/mission/webb/nircam/",
          "profile": null,
          "mid": null,
          "function": "two redundant modules, each with a dichroic splitting short and long wavelength channels",
          "specs": [
            {
              "label": "Redundancy",
              "value": "two nearly identical, fully redundant modules",
              "quote": "It consists of two, nearly identical, fully redundant",
              "source_url": "https://science.nasa.gov/mission/webb/nircam/"
            },
            {
              "label": "Supplier",
              "value": "University of Arizona and Lockheed Martin Advanced Technology Center",
              "quote": "NIRCam was developed by a team at the University of Arizona and Lockheed Martin’s Advanced Technology Center",
              "source_url": "https://science.nasa.gov/mission/webb/nircam/"
            }
          ]
        },
        {
          "part": "NIRCam coronagraphs",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "NIRCam is equipped with coronagraphs, instruments that allow astronomers to take pictures of very faint objects around a central bright",
          "source_url": "https://science.nasa.gov/mission/webb/nircam/",
          "profile": null,
          "mid": null,
          "function": "block bright starlight to see faint planets and disks"
        },
        {
          "part": "NIRSpec microshutter array (MSA)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": "Supplier: NASA Goddard Space Flight Center",
          "quote": "microshutter array (MSA) is a grid of 248,000 tiny doors",
          "source_url": "https://science.nasa.gov/mission/webb/nirspec/",
          "profile": null,
          "mid": null,
          "function": "grid of 248,000 tiny doors that lets NIRSpec observe about 100 objects at once; invented at NASA Goddard",
          "specs": [
            {
              "label": "Supplier",
              "value": "NASA",
              "quote": "NIRSpec was built for the European Space Agency by Airbus Industries with the Micro-Shutter Array (MSA) and detector sub-systems fabricated by NASA.",
              "source_url": "https://science.nasa.gov/mission/webb/nirspec/"
            },
            {
              "label": "Origin",
              "value": "Goddard invented the microshutter technology",
              "quote": "Goddard scientists and engineers invented the microshutter technology to control how light enters the NIRSpec.",
              "source_url": "https://science.nasa.gov/mission/webb/nirspec/"
            }
          ]
        },
        {
          "part": "NIRSpec instrument (Airbus for ESA)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": "Supplier: Airbus (for ESA)",
          "quote": "NIRSpec was built for the European Space Agency by Airbus Industries",
          "source_url": "https://science.nasa.gov/mission/webb/nirspec/",
          "profile": null,
          "mid": null,
          "function": "multi-object, integral-field and fixed-slit spectrograph"
        },
        {
          "part": "MIRI optical system",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": "Supplier: MIRI European Consortium",
          "quote": "The EC constructed and delivered the MIRI optical system",
          "source_url": "https://science.nasa.gov/mission/webb/mid-infrared-instrument-miri/",
          "profile": null,
          "mid": null,
          "function": "mid-infrared imager and spectrograph optics built by the European Consortium"
        },
        {
          "part": "MIRI detectors (three 1024 x 1024 Si:As)",
          "material": "arsenic-doped silicon (Si:As)",
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": "Supplier: NASA Jet Propulsion Laboratory",
          "quote": "JPL was responsible for the detectors (three 1024 X 1024 Si:As IBC devices), data chain, and flight software",
          "source_url": "https://science.nasa.gov/mission/webb/mid-infrared-instrument-miri/",
          "profile": null,
          "mid": "arsenic-doped-silicon",
          "function": "mid-infrared detectors; JPL responsible for detectors, data chain and flight software",
          "specs": [
            {
              "label": "Detector maker",
              "value": "Raytheon Vision Systems",
              "quote": "The mid-infrared detectors were made by Raytheon Vision Systems, which is also in California.",
              "source_url": "https://science.nasa.gov/mission/webb/infrared-detectors/"
            }
          ]
        },
        {
          "part": "MIRI coronagraphs (one Lyot, three four-quadrant phase mask)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "MIRI also contains one Lyot and three 4-quadrant phase mask",
          "source_url": "https://science.nasa.gov/mission/webb/mid-infrared-instrument-miri/",
          "profile": null,
          "mid": null,
          "function": "four coronagraphs for faint objects near bright stars"
        },
        {
          "part": "MIRI imager with nine broad-band filters",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "Imaging can be obtained with 9 broad-band filters",
          "source_url": "https://science.nasa.gov/mission/webb/mid-infrared-instrument-miri/",
          "profile": null,
          "mid": null,
          "function": "imaging channel"
        },
        {
          "part": "MIRI medium-resolution integral field unit",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "or with a medium spectral resolving power integral field unit",
          "source_url": "https://science.nasa.gov/mission/webb/mid-infrared-instrument-miri/",
          "profile": null,
          "mid": null,
          "function": "spectrograph channel"
        },
        {
          "part": "Fine Guidance Sensor (FGS)",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": "Supplier: Honeywell International (for the Canadian Space Agency)",
          "quote": "FGS is Webb’s guide camera, which helps point the telescope.",
          "source_url": "https://science.nasa.gov/mission/webb/integrated-science-instrument-module-isim/",
          "profile": null,
          "mid": null,
          "function": "Webb's guide camera that helps point the telescope",
          "specs": [
            {
              "label": "Supplier",
              "value": "Honeywell International",
              "quote": "Honeywell International designed and built the instrument in collaboration with a team lead by the Principal Investigator",
              "source_url": "https://science.nasa.gov/mission/webb/fine-guidance-sensor-near-infrared-imager-and-slitless-spectrograph-fgs-niriss/"
            },
            {
              "label": "Canadian contribution",
              "value": "built by the Canadian Space Agency",
              "quote": "FGS/NIRISS was built by the Canadian Space Agency.",
              "source_url": "https://science.nasa.gov/mission/webb/fine-guidance-sensor-near-infrared-imager-and-slitless-spectrograph-fgs-niriss/"
            }
          ]
        },
        {
          "part": "NIRISS aperture mask",
          "material": "metal plate (metal not stated)",
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "a metal plate with seven hexagonal holes that is placed in front of the detectors",
          "source_url": "https://science.nasa.gov/mission/webb/fine-guidance-sensor-near-infrared-imager-and-slitless-spectrograph-fgs-niriss/",
          "profile": null,
          "mid": "aperture-mask-metal-unspecified",
          "function": "metal plate with seven hexagonal holes in front of the detectors for aperture masking interferometry"
        },
        {
          "part": "NIRISS spectrograph and imager",
          "material": null,
          "form": null,
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "NIRISS gathers spectra (like NIRSpec), and capture images of the universe at near-infrared wavelengths (like NIRCam)",
          "source_url": "https://science.nasa.gov/mission/webb/integrated-science-instrument-module-isim/",
          "profile": null,
          "mid": null,
          "function": "slitless spectroscopy and near-infrared imaging"
        }
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          "part": "Near-infrared H2RG detectors (HgCdTe)",
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          "part": "Indium interconnects in the detector sandwich",
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          "part": "Silicon readout integrated circuit (ROIC)",
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          "standard": null,
          "hardware_ref": null,
          "quote": "The primary piece is the Cryocooler Compressor Assembly (CCA).",
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          "profile": null,
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              "quote": "The CCA is located in the heart of the spacecraft bus, on the sun-facing \"warm\" side of the observatory",
              "source_url": "https://science.nasa.gov/mission/webb/cryocooler/"
            },
            {
              "label": "Working fluid",
              "value": "helium gas",
              "quote": "using helium gas as a working fluid",
              "source_url": "https://science.nasa.gov/mission/webb/cryocooler/"
            },
            {
              "label": "Moving parts",
              "value": "only the two 2-cylinder pumps",
              "quote": "have no moving parts",
              "source_url": "https://science.nasa.gov/mission/webb/cryocooler/"
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          ]
        }
      ]
    },
    {
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          "part": "Payload adapter (Cone 3936 and ACU 2624)",
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          "source_url": "https://science.nasa.gov/mission/webb/launch/",
          "profile": null,
          "mid": null,
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          "part": "Long payload fairing (Ariane 5)",
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          "form": null,
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          "hardware_ref": null,
          "quote": "with a long payload fairing providing a maximum 4.57 meter static diameter and useable length of 16.19 meters",
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          "profile": null,
          "mid": null,
          "function": "4.57 m static diameter and 16.19 m useable length"
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      "id": "invar",
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      "target": "Ariane 5 ECA (Arianespace)",
      "target_slug": null,
      "note": "launched 25 December 2021 from ELA-3, Kourou; the vehicle and launch services were ESA's contribution",
      "quote": "Webb was launched on an Arianespace Ariane 5 ECA rocket.",
      "source_url": "https://science.nasa.gov/mission/webb/faqs-full/"
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    {
      "type": "launched_on",
      "target": "Vulcain 2 engine (Ariane 5 ECA main stage)",
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      "note": "single cryogenic engine on the EPC core stage, up to 137 tonnes of thrust",
      "quote": "The Vulcain cryogenic engine was modified to increase its thrust by 20%, up to 137 tonnes.",
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    {
      "type": "launched_on",
      "target": "HM7B engine (Ariane 5 ECA ESC-A upper stage)",
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      "type": "launched_on",
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    {
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      "note": "Secondary Combustion Augmented Thrusters for orbit correction, hydrazine and dinitrogen tetroxide",
      "quote": "Webb has two pairs of them (paired for redundancy). They use hydrazine and dinitrogen tetroxide",
      "source_url": "https://science.nasa.gov/mission/webb/spacecraft-bus/"
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    {
      "type": "carries",
      "target": "MRE-1 monopropellant thruster (x8)",
      "target_slug": null,
      "note": "hydrazine thrusters for attitude control and reaction-wheel unloading",
      "quote": "There are eight MRE-1s on Webb, and they are used for attitude control and momentum unloading of the reaction wheels.",
      "source_url": "https://science.nasa.gov/mission/webb/spacecraft-bus/"
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      "source_url": "https://science.nasa.gov/mission/webb/spacecraftoverview/"
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    {
      "type": "supplied_by",
      "target": "Northrop Grumman",
      "target_slug": null,
      "note": "backplane, sunshield assembly, spacecraft and final integration",
      "quote": "Northrop Grumman was responsible for the development of advanced graphite composite materials mated to titanium and invar fittings and interfaces.",
      "source_url": "https://science.nasa.gov/mission/webb/webbs-backplane/"
    },
    {
      "type": "supplied_by",
      "target": "Ball Aerospace",
      "target_slug": null,
      "note": "cryogenic testing of the primary mirror segments",
      "quote": "Cryogenic testing of the primary mirror segments began in at Marshall's XRCF by Ball Aerospace in 2009.",
      "source_url": "https://science.nasa.gov/mission/webb/webbs-mirrors/"
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    {
      "type": "supplied_by",
      "target": "Brush Wellman",
      "target_slug": null,
      "note": "purified the beryllium for the mirror blanks",
      "quote": "The beryllium to make Webb's mirror was mined in Utah and purified at Brush Wellman in Ohio.",
      "source_url": "https://science.nasa.gov/mission/webb/webbs-mirrors/"
    },
    {
      "type": "supplied_by",
      "target": "Axsys Technologies",
      "target_slug": null,
      "note": "shaped the beryllium blanks into segments",
      "quote": "Axsys Technologies shaped the mirror blanks into their final shape.",
      "source_url": "https://science.nasa.gov/mission/webb/webbs-mirrors/"
    },
    {
      "type": "supplied_by",
      "target": "SSG/Tinsley",
      "target_slug": null,
      "note": "polished the mirror segments",
      "quote": "they were sent to Richmond, CA, where SSG/Tinsley polished them",
      "source_url": "https://science.nasa.gov/mission/webb/webbs-mirrors/"
    },
    {
      "type": "supplied_by",
      "target": "Quantum Coating Incorporated",
      "target_slug": null,
      "note": "applied the gold coating by vacuum vapor deposition",
      "quote": "Quantum Coating Incorporated did the coatings on our telescope mirrors.",
      "source_url": "https://science.nasa.gov/mission/webb/webbs-mirrors/"
    },
    {
      "type": "supplied_by",
      "target": "Airbus",
      "target_slug": null,
      "note": "built NIRSpec for ESA",
      "quote": "NIRSpec was built for the European Space Agency by Airbus Industries",
      "source_url": "https://science.nasa.gov/mission/webb/nirspec/"
    },
    {
      "type": "supplied_by",
      "target": "Lockheed Martin Advanced Technology Center and University of Arizona",
      "target_slug": null,
      "note": "developed NIRCam",
      "quote": "NIRCam was developed by a team at the University of Arizona and Lockheed Martin’s Advanced Technology Center",
      "source_url": "https://science.nasa.gov/mission/webb/nircam/"
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    {
      "type": "supplied_by",
      "target": "Honeywell International",
      "target_slug": null,
      "note": "designed and built FGS/NIRISS for the Canadian Space Agency",
      "quote": "Honeywell International designed and built the instrument in collaboration with a team lead by the Principal Investigator",
      "source_url": "https://science.nasa.gov/mission/webb/fine-guidance-sensor-near-infrared-imager-and-slitless-spectrograph-fgs-niriss/"
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    {
      "type": "supplied_by",
      "target": "Teledyne Imaging Sensors",
      "target_slug": null,
      "note": "near-infrared H2RG detectors",
      "quote": "The near-infrared detectors were made by Teledyne Imaging Sensors in California.",
      "source_url": "https://science.nasa.gov/mission/webb/infrared-detectors/"
    },
    {
      "type": "supplied_by",
      "target": "Raytheon Vision Systems",
      "target_slug": null,
      "note": "mid-infrared Si:As detectors",
      "quote": "The mid-infrared detectors were made by Raytheon Vision Systems, which is also in California.",
      "source_url": "https://science.nasa.gov/mission/webb/infrared-detectors/"
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    {
      "type": "supplied_by",
      "target": "NASA Jet Propulsion Laboratory",
      "target_slug": null,
      "note": "MIRI detectors, data chain and flight software",
      "quote": "JPL was responsible for the detectors (three 1024 X 1024 Si:As IBC devices), data chain, and flight software",
      "source_url": "https://science.nasa.gov/mission/webb/mid-infrared-instrument-miri/"
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    {
      "type": "supplied_by",
      "target": "European Space Agency",
      "target_slug": null,
      "note": "NIRSpec, MIRI optics assembly, the Ariane launch vehicle and launch services",
      "quote": "Near Infrared Spectrograph, Mid-Infrared Instrument Optics Assembly, and the Ariane Launch Vehicle and launch services.",
      "source_url": "https://science.nasa.gov/mission/webb/webb-team/"
    },
    {
      "type": "supplied_by",
      "target": "Canadian Space Agency",
      "target_slug": null,
      "note": "Fine Guidance Sensor and NIRISS",
      "quote": "Fine Guidance Sensor/Near Infrared Imager and Slitless Spectrograph",
      "source_url": "https://science.nasa.gov/mission/webb/webb-team/"
    },
    {
      "type": "operated_by",
      "target": "Space Telescope Science Institute (AURA)",
      "target_slug": null,
      "note": "operates Webb for NASA",
      "quote": "is operated by AURA’s Space Telescope Science Institute",
      "source_url": "https://jwst-docs.stsci.edu/jwst-observatory-hardware/jwst-spacecraft-bus"
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  "not_published": "Alloy or grade of the beryllium (e.g. S-200F), mirror substrate lightweighting, sunshield membrane thickness per layer, backplane fibre/resin, MLI, spacecraft-bus structure and solar-cell materials are not stated in the NASA pages read. Mirror segment manufacturer not confirmed in this entry. More detail: Not published on the pages read: the makers of the SCAT and MRE-1 thrusters and the propellant tanks, the solar array cell type and maker, the battery chemistry and maker, the star tracker, gyroscope, reaction wheel and sun sensor makers, the high-gain antenna materials, the sunshield boom and spreader materials, MLI film types, the NIRSpec optics material, and the mirror actuator maker. Ball Aerospace's exact role as optical subcontractor is only shown through mirror testing credits on the NASA page. Ariane 5 ECA is not in the catalog (only Ariane 6 is), so its engines are linked as plain names; the ESA page says the ECA used the Vulcain 2 and HM7B engines, not Vulcain 2.1 or Vinci. The 'two pairs of SCATs' count in the entry uses NASA wording; no engine in the catalog flew on Webb.",
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      "credit": "NASA/MSFC/David Higginbotham/Emmett Given (http://www.jwst.nasa.gov/images_mirror45.html) / via Wikimedia Commons",
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