{
  "id": "esa-cheops",
  "title": "CHEOPS",
  "maker": "ESA",
  "maker_type": "Space agency",
  "kind": "mission",
  "category": "missions",
  "page": "https://spacemushroom.com/space-products/esa-cheops/",
  "website": "https://sci.esa.int/web/cheops/-/59012-7-cheops-telescope-arrives-at-new-home",
  "summary": "ESA small science mission (exoplanet photometer); the ESA page describes the telescope tube structure made in CFRP.",
  "application": "ESA's exoplanet photometer, which measures how starlight dips when a planet passes in front of its star. The carbon-fibre telescope tube keeps the optics stable and light, which is why the mission shows how structural materials support precision science.",
  "story": {
    "headline": "ESA's CHEOPS telescope measures the dip in a star's light when a planet passes in front of it.",
    "intro": [
      "CHEOPS is a small science mission run by the European Space Agency (ESA). Its telescope is a photometer, an instrument that measures brightness. It watches for the dip in a star's light when a planet passes in front of it. Planets that circle other stars are called exoplanets.",
      "The telescope tube is carbon-fibre reinforced plastic, designed by the Swiss company Almatech down to the level of single layers, called laminae. The carbon fibre keeps the optics stable and light. A 95 cm baffle, a shield against stray light, protects them."
    ],
    "built": [
      {
        "title": "The telescope tube",
        "text": "The tube assembly carries the baffle, a radiator, the focal plane module and the star trackers. The module sits where the image forms, and the trackers read the stars to work out where the telescope is pointing. Inside are two hyperbolic mirrors, a 320 mm primary and a 68 mm secondary.",
        "parts": [
          "Telescope tube assembly (TTA) structure"
        ]
      },
      {
        "title": "Baffle and cover release",
        "text": "The baffle keeps stray light from reaching the telescope, and so does a field stop in the back-end optics. A titanium bolt surrounded by a cylinder of shape memory alloy, a metal that changes shape when heated, releases the baffle's cover.",
        "parts": [
          "Telescope baffle (95 cm long)",
          "Fastening bolt",
          "Release cylinder"
        ]
      },
      {
        "title": "Body and heat control",
        "text": "The spacecraft body, called the platform, has top, bottom and side panels built as sandwiches with metal skins. Layered insulation blankets cover the outside, and foil radiators shed heat from the electronics. Fillers improve thermal contact with the mounting panel, while washers reduce it.",
        "parts": [
          "Top, bottom and side panels",
          "Multi-layer insulation",
          "Radiator foils",
          "Interface fillers",
          "Thermal washers"
        ]
      }
    ],
    "materials": [
      {
        "name": "Carbon-fibre reinforced plastic",
        "mid": "carbon-fibre",
        "where": "The telescope tube structure, designed by Almatech down to the individual layers."
      },
      {
        "name": "Titanium",
        "mid": "titanium",
        "where": "The bolt that fastens the baffle cover, and two engraved commemorative plaques."
      },
      {
        "name": "Shape memory alloy",
        "mid": "shape-memory-alloy",
        "where": "The cylinder around the baffle cover bolt, part of its release."
      }
    ],
    "connections": "A Soyuz-Fregat rocket launched CHEOPS from Europe's Spaceport on 18 December 2019. Almatech built the structure of the telescope tube. Arquimea, a maker of thermal blankets, names CHEOPS among the missions that have flown its blankets.",
    "unknown": "ESA does not say which carbon fibre and resin form the tube, or how its layers are stacked. It does not name the materials of the baffle, the radiator, the solar array, the insulation films or the black coatings, or the metal skins of the body panels. Nor does it give the spacecraft's power use.",
    "facts": [
      {
        "label": "Orbit",
        "value": "Sun-synchronous dusk-dawn, 700 km"
      },
      {
        "label": "Launch",
        "value": "18 December 2019, Soyuz-Fregat, Europe's Spaceport"
      },
      {
        "label": "Planned life",
        "value": "3.5 years nominal science operations"
      },
      {
        "label": "Primary mirror",
        "value": "320 mm hyperbolic"
      },
      {
        "label": "Field of view",
        "value": "19x19 arcmin"
      },
      {
        "label": "Data volume",
        "value": "1.2 Gbit/day"
      }
    ]
  },
  "specifications": [
    {
      "label": "Mass",
      "value": "280 kg",
      "source_url": "https://www.esa.int/Science_Exploration/Space_Science/Cheops/(highlights)",
      "quote": "280 kg"
    },
    {
      "label": "Size",
      "value": "1.5 m",
      "source_url": "https://www.esa.int/Science_Exploration/Space_Science/Cheops/(highlights)",
      "quote": "1.5 m"
    },
    {
      "label": "Orbit",
      "value": "Sun-synchronous dusk-dawn, 700 km",
      "source_url": "https://www.esa.int/Science_Exploration/Space_Science/Cheops/(highlights)",
      "quote": "Sun-synchronous, dusk-dawn orbit at 700 km above Earth"
    },
    {
      "label": "Launch",
      "value": "18 December 2019, Soyuz-Fregat, Europe's Spaceport",
      "source_url": "https://www.esa.int/Science_Exploration/Space_Science/Cheops/(highlights)",
      "quote": "18 December 2019"
    },
    {
      "label": "Launch time",
      "value": "08:54:20 UTC",
      "source_url": "https://sci.esa.int/web/cheops/54034-operations",
      "quote": "CHEOPS was successfully launched on 18 December 2019, at 08:54:20 UTC"
    },
    {
      "label": "Lifetime",
      "value": "3.5 years nominal science operations",
      "source_url": "https://sci.esa.int/web/cheops/54034-operations",
      "quote": "The nominal duration of science operations is 3.5 years."
    },
    {
      "label": "Primary mirror",
      "value": "320 mm hyperbolic",
      "source_url": "https://sci.esa.int/web/cheops/-/59012-7-cheops-telescope-arrives-at-new-home",
      "quote": "a 320-mm hyperbolic primary mirror"
    },
    {
      "label": "Secondary mirror",
      "value": "68 mm hyperbolic",
      "source_url": "https://sci.esa.int/web/cheops/-/59012-7-cheops-telescope-arrives-at-new-home",
      "quote": "a 68-mm hyperbolic secondary mirror"
    },
    {
      "label": "Field of view",
      "value": "19x19 arcmin",
      "source_url": "https://www.esa.int/Science_Exploration/Space_Science/Cheops/(highlights)",
      "quote": "19×19 arcmin field of view"
    },
    {
      "label": "Data volume",
      "value": "1.2 Gbit/day",
      "source_url": "https://www.esa.int/Science_Exploration/Space_Science/Cheops/(highlights)",
      "quote": "1.2 Gbit/day data"
    }
  ],
  "features": [
    {
      "text": "Telescope tube assembly with star trackers, instrument radiator, baffle and focal plane module",
      "source_url": "https://sci.esa.int/web/cheops/-/59012-7-cheops-telescope-arrives-at-new-home",
      "quote": "the star trackers, the instrument radiator, the baffle, and the focal plane module"
    },
    {
      "text": "Baffle and field stop reject stray light",
      "source_url": "https://sci.esa.int/web/cheops/-/59012-7-cheops-telescope-arrives-at-new-home",
      "quote": "Both the baffle and the field stop in the back-end optics have been designed to reject this stray light."
    }
  ],
  "parts": [
    {
      "assembly": "Telescope (OTA)",
      "parts": [
        {
          "part": "Telescope tube assembly (TTA) structure",
          "material": "carbon-fibre reinforced plastics (CFRP)",
          "form": "laminate (designed to lamina level)",
          "finish": null,
          "standard": null,
          "hardware_ref": "Almatech (Swiss) built the TTA structure",
          "quote": "manufacturing the telescope structure from carbon-fibre reinforced plastics (CFRP)",
          "source_url": "https://sci.esa.int/web/cheops/-/59012-7-cheops-telescope-arrives-at-new-home",
          "profile": "carbon-fibre",
          "mid": "carbon-fibre"
        },
        {
          "part": "TTA structure design basis",
          "material": "CFRP laminate",
          "form": "laminate",
          "finish": null,
          "standard": null,
          "hardware_ref": "Almatech",
          "quote": "Swiss company Almatech, which was responsible for the TTA structure, designed it down to the lamina level.",
          "source_url": "https://www.eoportal.org/satellite-missions/cheops",
          "profile": "carbon-fibre",
          "mid": "carbon-fibre"
        },
        {
          "part": "Telescope baffle (95 cm long)",
          "material": null,
          "form": "baffle",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "a 95 cm long baffle that shields the Cheops telescope from straylight",
          "source_url": "https://www.eoportal.org/satellite-missions/cheops",
          "profile": null,
          "mid": null
        }
      ]
    },
    {
      "assembly": "Baffle cover release",
      "parts": [
        {
          "part": "Fastening bolt",
          "material": "titanium",
          "form": "bolt",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "a titanium fastening bolt surrounded by a cylinder made of a shape memory alloy",
          "source_url": "https://www.eoportal.org/satellite-missions/cheops",
          "profile": "titanium",
          "mid": "titanium"
        },
        {
          "part": "Release cylinder",
          "material": "shape memory alloy (alloy not named)",
          "form": "cylinder",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "a cylinder made of a shape memory alloy",
          "source_url": "https://www.eoportal.org/satellite-missions/cheops",
          "profile": null,
          "mid": "shape-memory-alloy"
        }
      ]
    },
    {
      "assembly": "Platform",
      "parts": [
        {
          "part": "Top, bottom and side panels",
          "material": "sandwiches with metallic skins (metal and core not stated)",
          "form": "sandwich panel",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The structure design is made of sandwiches with metallic skins for top-bottom-side panels",
          "source_url": "https://www.eoportal.org/satellite-missions/cheops",
          "profile": null,
          "mid": null
        },
        {
          "part": "Launcher interface",
          "material": "clamp-band system",
          "form": "clamp-band",
          "finish": null,
          "standard": null,
          "hardware_ref": "937 standard clamp-band",
          "quote": "a 937 standard clamp-band system is proposed",
          "source_url": "https://www.eoportal.org/satellite-missions/cheops",
          "profile": null,
          "mid": null
        }
      ]
    },
    {
      "assembly": "Platform thermal control",
      "parts": [
        {
          "part": "Multi-layer insulation",
          "material": "not named",
          "form": "MLI",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "MLIs to provide insulation from the external environment",
          "source_url": "https://www.eoportal.org/satellite-missions/cheops",
          "profile": null,
          "mid": null
        },
        {
          "part": "Radiator foils",
          "material": "not named",
          "form": "foil",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "Radiator foils to allow rejection of the heat dissipated by electronic units",
          "source_url": "https://www.eoportal.org/satellite-missions/cheops",
          "profile": null,
          "mid": null
        },
        {
          "part": "Black coatings",
          "material": "not named",
          "form": "coating",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "Black coatings to increase the radiative coupling inside the platform",
          "source_url": "https://www.eoportal.org/satellite-missions/cheops",
          "profile": null,
          "mid": null
        },
        {
          "part": "Interface fillers",
          "material": "not named",
          "form": "filler",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "Interface fillers to increase the thermal contact with the mounting panel",
          "source_url": "https://www.eoportal.org/satellite-missions/cheops",
          "profile": null,
          "mid": null
        },
        {
          "part": "Thermal washers",
          "material": "not named",
          "form": "washer",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "Thermal washers to conductively decouple from the mounting panel",
          "source_url": "https://www.eoportal.org/satellite-missions/cheops",
          "profile": null,
          "mid": null
        }
      ]
    },
    {
      "assembly": "Plaques",
      "parts": [
        {
          "part": "Commemorative plaques (2)",
          "material": "titanium",
          "form": "plate, engraved",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "engraved them onto two titanium plates",
          "source_url": "https://www.eoportal.org/satellite-missions/cheops",
          "profile": "titanium",
          "mid": "titanium"
        }
      ]
    }
  ],
  "materials": [
    {
      "id": "carbon-fibre",
      "name": "CFRP laminate",
      "material_page": "https://spacemushroom.com/profiles/carbon-fibre/"
    },
    {
      "id": "titanium",
      "name": "titanium",
      "material_page": "https://spacemushroom.com/profiles/titanium/"
    },
    {
      "id": "shape-memory-alloy",
      "name": "shape memory alloy (alloy not named)",
      "material_page": null
    }
  ],
  "standards": [],
  "relations": [],
  "not_published": "No CFRP fibre, resin or layup data, no baffle, radiator, sunshield or solar-array materials, no MLI film types, no coating names, and no standards are given on the pages read.",
  "depth": "partial",
  "photos": [
    {
      "file": "products/gallery/esa-cheops-1.jpg",
      "alt": "People in clean-room suits working on the CHEOPS spacecraft, with copper-coloured foil on its front ring",
      "long": "People in clean-room suits work on the CHEOPS spacecraft. Black multilayer insulation covers the telescope tube, copper-coloured foil covers the front ring, and a large chamber stands on the left.",
      "kind": "product",
      "credit": "Universitaetbern",
      "license": "CC BY-SA 4.0",
      "page_url": "https://commons.wikimedia.org/wiki/File:Unibe_space_01963_201801_1200.jpg"
    },
    {
      "file": "products/gallery/esa-cheops-2.jpg",
      "alt": "CHEOPS spacecraft on a rotating fixture in a clean room, covered in black thermal blankets",
      "long": "The CHEOPS spacecraft on a rotating handling fixture in a clean room hall. Black multilayer insulation blankets held with blue tape cover the telescope tube and body, a grey panel carries an Airbus logo and the mission name, and visitors in blue suits stand behind a tape barrier on the left.",
      "kind": "product",
      "credit": "Universitaetbern",
      "license": "CC BY-SA 4.0",
      "page_url": "https://commons.wikimedia.org/wiki/File:Unibe_CHEOPS_020_20200616_1200.jpg"
    },
    {
      "file": "products/gallery/esa-cheops-3.jpg",
      "alt": "Gloved hand reflected in a round mirror inside a dark telescope tube, with a small square sensor at the centre",
      "kind": "product",
      "credit": "Broeg",
      "license": "CC BY 4.0",
      "page_url": "https://commons.wikimedia.org/wiki/File:CHEOPS_CCD_Detector_photographed_through_flight_optics.jpg",
      "long": "A close, blurred view through black optics. A circular mirror shows a gloved hand and a small dark square detector."
    },
    {
      "file": "products/gallery/esa-cheops-4.jpg",
      "alt": "Flat illustration of the CHEOPS spacecraft: dark body, round telescope aperture, grey panels, gold edge, on a navy background",
      "long": "A large dark round aperture faces the viewer, with light grey panels and a thin gold strip along one edge, on a navy background.",
      "kind": "artwork",
      "credit": "ESA",
      "license": "CC BY-SA 3.0 IGO",
      "page_url": "https://commons.wikimedia.org/wiki/File:CHEOPS_spacecraft.jpg"
    }
  ],
  "context": {
    "size": [
      "Microsatellite (over 50 kg)"
    ],
    "mass": [
      "Over 100 kg"
    ],
    "orbit": [
      "Sun-synchronous"
    ]
  },
  "licence": "Product data CC BY 4.0, cite Space Mushroom. Photos keep their own licences, given per photo.",
  "mcp": "https://spacemushroom.com/mcp"
}