{
  "id": "esa-proba-v",
  "title": "Proba-V",
  "maker": "ESA",
  "maker_type": "Space agency",
  "kind": "satellite",
  "category": "missions",
  "page": "https://spacemushroom.com/space-products/esa-proba-v/",
  "website": "https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Proba_Missions/Proba-V_keeps_its_cool_in_space_simulation",
  "summary": "ESA small vegetation-monitoring satellite; the ESA page describes thermal-vacuum testing of its structural and thermal model and the thermal design of the Vegetation sensor.",
  "application": "A small ESA satellite that monitors vegetation worldwide and carries guest experiments. Its public pages describe thermal-vacuum testing of the structure, which makes it a useful reference for qualifying a small Earth-observation platform.",
  "story": {
    "headline": "Proba-V is a small ESA satellite that watches the world's vegetation and carries guest experiments.",
    "intro": [
      "Proba-V, a small satellite from the European Space Agency (ESA), monitors vegetation worldwide from a polar orbit 820 km up. It crosses the equator every morning between 10:30 and 11:00 local time. Its Vegetation imager sees a strip of ground 2250 km wide.",
      "The Vegetation sensor has to live with big temperature swings. Its sunlit face might reach 100 °C while the side facing deep space can drop to minus 50 °C or lower. Titanium isolators, chosen because they conduct heat poorly, join it to the rest of the satellite, and a dozen layers of insulation wrap it."
    ],
    "built": [
      {
        "title": "The structure",
        "text": "The body is an H-shaped structure of aluminium honeycomb panels, light sandwiches with a cellular core. The thin face sheets are aluminium alloy 2024-T3, 0.8 mm thick on the inner panels and 0.4 mm on the top and Earth-facing panels. Edge profiles and inserts are alloy 7075-T7351, and three outer panels are carbon-fibre composite.",
        "parts": [
          "Honeycomb panel face sheets",
          "Honeycomb core",
          "Edge profiles and hot inserts",
          "Outer panels (3)"
        ]
      },
      {
        "title": "The Vegetation instrument",
        "text": "The instrument has three telescopes. Each telescope's structure and mirrors are made of the same aluminium, in an athermal design, which means temperature changes should not upset the optics. A very accurately machined titanium structure ties the focal plane together, and titanium feet mount the instrument.",
        "parts": [
          "Telescope (structure and mirrors, 3 telescopes)",
          "Focal plane interconnecting structure",
          "Instrument mounting feet / flexures"
        ]
      },
      {
        "title": "Keeping the temperature steady",
        "text": "A 12-layer wrap of multi-layer insulation covers the instrument, and its radiator is covered with aluminised Teflon. For the satellite as a whole, thermal control is passive, using insulation and paint. A structural and thermal model, a stand-in for the real satellite, stayed within its temperature limits in a vacuum chamber.",
        "parts": [
          "Instrument thermal wrap",
          "Instrument radiator",
          "Platform thermal control"
        ]
      },
      {
        "title": "Power and radio",
        "text": "The solar array has gallium arsenide cells under cover glass, arranged in 25 strings of 18. The battery is 12 Ah lithium-ion, made of ABSL 18650HC cells. In the radio, a gallium nitride amplifier flies as a guest technology.",
        "parts": [
          "Photovoltaic array",
          "Battery",
          "Communication amplifier"
        ]
      }
    ],
    "materials": [
      {
        "name": "Aluminium 2024-T3",
        "mid": "aluminium-2024",
        "where": "The face sheets of the honeycomb panels, 0.8 mm thick inside and 0.4 mm on the top and Earth-facing panels."
      },
      {
        "name": "Carbon fibre",
        "mid": "carbon-fibre",
        "where": "Three outer panels, made of carbon-fibre composite."
      },
      {
        "name": "Titanium",
        "mid": "titanium",
        "where": "The isolators, the focal plane structure and the mounting feet of the Vegetation instrument."
      },
      {
        "name": "Aluminium",
        "mid": "aluminium",
        "where": "The three telescopes and their mirrors, all in the same aluminium."
      },
      {
        "name": "Gallium arsenide",
        "mid": "gallium-arsenide",
        "where": "The solar cells, under cover glass."
      },
      {
        "name": "Gallium nitride",
        "mid": "gallium-nitride",
        "where": "The amplifier in the communication system, flown as a guest technology."
      }
    ],
    "connections": "Proba-V is one of ESA's Proba missions, and a Vega rocket launched it on 7 May 2013. Its Vegetation imager is a new version of the one flown on the Spot satellites. Guest experiments on board include an Energetic Particle Telescope, the SATRAM radiation monitor, an ADS-B detector for aircraft signals and a fibre optic photonics experiment.",
    "unknown": "ESA does not name the alloy of the honeycomb core, the adhesives, fasteners, paints or insulation films, or the base material under the radiator's aluminised Teflon. It gives no figures for the satellite's power, size or lifetime.",
    "facts": [
      {
        "label": "Orbit",
        "value": "Sun-synchronous polar, 820 km"
      },
      {
        "label": "Launch",
        "value": "7 May 2013, Vega"
      },
      {
        "label": "Swath",
        "value": "2250 km"
      },
      {
        "label": "Sensor temperature extremes",
        "value": "sunlit face up to 100 C, deep-space side down to -50 C"
      },
      {
        "label": "Guest technology",
        "value": "Gallium nitride amplifier in comms subsystem"
      }
    ]
  },
  "specifications": [
    {
      "label": "Mass",
      "value": "140 kg",
      "source_url": "https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Proba_Missions/About_Proba-V",
      "quote": "140 kg"
    },
    {
      "label": "Orbit",
      "value": "Sun-synchronous polar, 820 km",
      "source_url": "https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Proba_Missions/About_Proba-V",
      "quote": "Sun-synchronous polar orbit, 820 km altitude, crossing the equator every morning between 10:30 and 11:00 local time"
    },
    {
      "label": "Launch",
      "value": "7 May 2013, Vega",
      "source_url": "https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Proba_Missions/About_Proba-V",
      "quote": "02:06 GMT on 7 May 2013 (23:06 local time 6 May; 04:06 CEST 7 May)"
    },
    {
      "label": "Launcher",
      "value": "Vega",
      "source_url": "https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Proba_Missions/About_Proba-V",
      "quote": "Vega"
    },
    {
      "label": "Payload",
      "value": "Vegetation imager",
      "source_url": "https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Proba_Missions/About_Proba-V",
      "quote": "New version of the Vegetation imager previously flown on the Spot satellites"
    },
    {
      "label": "Swath",
      "value": "2250 km",
      "source_url": "https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Proba_Missions/Proba-V_keeps_its_cool_in_space_simulation",
      "quote": "multispectral surface monitoring across an extremely wide 2250 km swath"
    },
    {
      "label": "Guest technology",
      "value": "Gallium nitride amplifier in comms subsystem",
      "source_url": "https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Proba_Missions/About_Proba-V",
      "quote": "Gallium nitride amplifier incorporated in communication subsystem"
    },
    {
      "label": "Temperature extremes (sensor)",
      "value": "sunlit face up to 100 C, deep-space side down to -50 C",
      "source_url": "https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Proba_Missions/Proba-V_keeps_its_cool_in_space_simulation",
      "quote": "its sunlit face might reach 100°C while the side facing deep space can drop to –50°C or lower"
    }
  ],
  "features": [
    {
      "text": "Guest experiments: EPT, SATRAM, ADS-B detector, fibre optic photonics",
      "source_url": "https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Proba_Missions/About_Proba-V",
      "quote": "Energetic Particle Telescope; SATRAM radiation monitor, ADS-B aircraft signal detector; fibre optic photonics experiment"
    },
    {
      "text": "Structural and thermal model passed thermal-vacuum test",
      "source_url": "https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Proba_Missions/Proba-V_keeps_its_cool_in_space_simulation",
      "quote": "maintained its desired temperature boundaries within simulated space conditions"
    }
  ],
  "parts": [
    {
      "assembly": "Bus structure (eoPortal subsystem table)",
      "parts": [
        {
          "part": "Honeycomb panel face sheets",
          "material": "Aluminum (AA2024-T3)",
          "form": "sheet (t = 0.8 mm inner panels, t = 0.4 mm top and nadir panel)",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "Aluminum (AA2024-T3): Face sheets t = 0.8 mm inner panels, t = 0.4 mm top and nadir panel), honeycomb core (t = 10. 8 mm)",
          "source_url": "https://www.eoportal.org/satellite-missions/proba-v",
          "profile": "aluminium-2024",
          "mid": "aluminium-2024"
        },
        {
          "part": "Honeycomb core",
          "material": null,
          "form": "honeycomb (t = 10.8 mm)",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "honeycomb core (t = 10. 8 mm)",
          "source_url": "https://www.eoportal.org/satellite-missions/proba-v",
          "profile": null,
          "mid": null
        },
        {
          "part": "Edge profiles and hot inserts",
          "material": "Aluminum (AA7075-T7351)",
          "form": "machined profile / insert",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "Aluminum (AA7075-T7351): edge profiles, hot inserts",
          "source_url": "https://www.eoportal.org/satellite-missions/proba-v",
          "profile": "aluminium-7075",
          "mid": "aluminium-7075"
        },
        {
          "part": "Outer panels (3)",
          "material": "CFRP (EX-1515/M55J + Redux 312L)",
          "form": "CFRP panel",
          "finish": null,
          "standard": null,
          "hardware_ref": "EX-1515/M55J; Redux 312L",
          "quote": "3 CFRP (EX-1515/M55J + Redux 312L) outer panels",
          "source_url": "https://www.eoportal.org/satellite-missions/proba-v",
          "profile": "carbon-fibre",
          "mid": "carbon-fibre"
        },
        {
          "part": "Structure (summary)",
          "material": "Aluminium honeycomb",
          "form": "H-structure",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "Structure Aluminium honeycomb H-structure",
          "source_url": "https://www.eoportal.org/satellite-missions/proba-v",
          "profile": "aluminium-honeycomb-hexweb",
          "mid": "aluminium-honeycomb-hexweb"
        }
      ]
    },
    {
      "assembly": "Power, thermal, RF",
      "parts": [
        {
          "part": "Photovoltaic array",
          "material": "Triple junction GaAs cells (3G-28%) with cover glass CMG 100AR coating",
          "form": "cell + coverglass",
          "finish": null,
          "standard": null,
          "hardware_ref": "3G-28%; CMG 100AR",
          "quote": "Photo-Voltaic Array : Triple junction GaAs cells (3G-28%) Cover glass CMG 100AR coating, 25 strings, 18 cells per string",
          "source_url": "https://www.eoportal.org/satellite-missions/proba-v",
          "profile": "gallium-arsenide",
          "mid": "gallium-arsenide"
        },
        {
          "part": "Battery",
          "material": "Li-ion",
          "form": "cell",
          "finish": null,
          "standard": null,
          "hardware_ref": "ABSL 18650HC",
          "quote": "Battery:12 Ah Li-ion (7s8p) ABSL 18650HC cells",
          "source_url": "https://www.eoportal.org/satellite-missions/proba-v",
          "profile": null,
          "mid": "lithium-ion-cell"
        },
        {
          "part": "Platform thermal control",
          "material": "MLI and paint (types not named)",
          "form": "film / coating",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "Thermal Passive (MLI and paint)",
          "source_url": "https://www.eoportal.org/satellite-missions/proba-v",
          "profile": null,
          "mid": null
        },
        {
          "part": "Communication amplifier",
          "material": "Gallium nitride",
          "form": "semiconductor",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "Gallium nitride amplifier incorporated in communication subsystem",
          "source_url": "https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Proba_Missions/About_Proba-V",
          "profile": "gallium-nitride",
          "mid": "gallium-nitride"
        }
      ]
    },
    {
      "assembly": "Vegetation instrument (VGT-P)",
      "parts": [
        {
          "part": "Telescope (structure and mirrors, 3 telescopes)",
          "material": "aluminum (same material for structure and mirrors; alloy not stated)",
          "form": "machined, SPDT mirrors",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "The entire telescope (structure and mirrors included) is an athermal design made of the same aluminum material.",
          "source_url": "https://www.eoportal.org/satellite-missions/proba-v",
          "profile": "aluminium",
          "mid": "aluminium"
        },
        {
          "part": "Focal plane interconnecting structure",
          "material": "titanium",
          "form": "machined structure",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "a very accurately machined interconnecting structure in titanium",
          "source_url": "https://www.eoportal.org/satellite-missions/proba-v",
          "profile": "titanium",
          "mid": "titanium"
        },
        {
          "part": "Instrument mounting feet / flexures",
          "material": "titanium",
          "form": "quasi-isostatic feet",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "the instrument is mounted by means of titanium quasi isostatic mounting feet",
          "source_url": "https://www.eoportal.org/satellite-missions/proba-v",
          "profile": "titanium",
          "mid": "titanium"
        },
        {
          "part": "Titanium isolators (ESA page)",
          "material": "Titanium",
          "form": "isolator",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "Titanium isolators, especially chosen for their poor conductivity, attach it to the rest of the satellite.",
          "source_url": "https://www.esa.int/Enabling_Support/Space_Engineering_Technology/Proba_Missions/Proba-V_keeps_its_cool_in_space_simulation",
          "profile": "titanium",
          "mid": "titanium"
        },
        {
          "part": "Instrument thermal wrap",
          "material": "MLI, 12 layers (film not named)",
          "form": "multi-layer insulation",
          "finish": null,
          "standard": null,
          "hardware_ref": null,
          "quote": "the instrument is completely wrapped in a 12 layer MLI",
          "source_url": "https://www.eoportal.org/satellite-missions/proba-v",
          "profile": "multilayer-insulation-mli",
          "mid": "multilayer-insulation-mli"
        },
        {
          "part": "Instrument radiator",
          "material": "aluminized Teflon covering (radiator base material not stated)",
          "form": "radiator coating",
          "finish": "aluminized Teflon",
          "standard": null,
          "hardware_ref": null,
          "quote": "the radiator, covered with aluminized Teflon",
          "source_url": "https://www.eoportal.org/satellite-missions/proba-v",
          "profile": "fep",
          "mid": "fep"
        }
      ]
    }
  ],
  "materials": [
    {
      "id": "aluminium-2024",
      "name": "Aluminum (AA2024-T3)",
      "material_page": "https://spacemushroom.com/profiles/aluminium-2024/"
    },
    {
      "id": "aluminium-7075",
      "name": "Aluminum (AA7075-T7351)",
      "material_page": "https://spacemushroom.com/profiles/aluminium-7075/"
    },
    {
      "id": "carbon-fibre",
      "name": "CFRP (EX-1515/M55J + Redux 312L)",
      "material_page": "https://spacemushroom.com/profiles/carbon-fibre/"
    },
    {
      "id": "aluminium-honeycomb-hexweb",
      "name": "Aluminium honeycomb",
      "material_page": "https://spacemushroom.com/profiles/aluminium-honeycomb-hexweb/"
    },
    {
      "id": "gallium-arsenide",
      "name": "Triple junction GaAs cells (3G-28%) with cover glass CMG 100AR coating",
      "material_page": "https://spacemushroom.com/profiles/gallium-arsenide/"
    },
    {
      "id": "lithium-ion-cell",
      "name": "Li-ion",
      "material_page": null
    },
    {
      "id": "gallium-nitride",
      "name": "Gallium nitride",
      "material_page": "https://spacemushroom.com/profiles/gallium-nitride/"
    },
    {
      "id": "aluminium",
      "name": "aluminum (same material for structure and mirrors; alloy not stated)",
      "material_page": "https://spacemushroom.com/profiles/aluminium/"
    },
    {
      "id": "titanium",
      "name": "Titanium",
      "material_page": "https://spacemushroom.com/profiles/titanium/"
    },
    {
      "id": "multilayer-insulation-mli",
      "name": "MLI, 12 layers (film not named)",
      "material_page": "https://spacemushroom.com/profiles/multilayer-insulation-mli/"
    },
    {
      "id": "fep",
      "name": "aluminized Teflon covering (radiator base material not stated)",
      "material_page": "https://spacemushroom.com/profiles/fep/"
    }
  ],
  "standards": [
    {
      "name": "AA2024-T3 and AA7075-T7351 (alloy-temper designations)",
      "org": "other",
      "used_for": "face sheets; edge profiles and hot inserts. No AMS/ASTM specification is cited"
    }
  ],
  "relations": [],
  "not_published": "Honeycomb core alloy and cell size, adhesives (only 'Redux 312L' named, with no stated role beyond the CFRP bracket), fasteners, MLI film types, paint products and radiator base material are not stated. The table is a heritage/equipment table, so panel-by-panel positions are not given.",
  "depth": "partial",
  "photos": [
    {
      "file": "products/context/esa-proba-v-3.jpg",
      "alt": "Assembled Proba-V microsatellite on a white stand in a clean room, with two technicians beside it",
      "long": "The assembled Proba-V microsatellite, a cuboid with dark solar cells on its visible faces, on a white stand in a clean room, with two technicians in QinetiQ Space suits beside it.",
      "kind": "product",
      "credit": "ESA-S. Corvaja, 2012",
      "license": "ESA Standard Licence",
      "page_url": "https://www.esa.int/ESA_Multimedia/Images/2012/12/Proba-V_integration"
    },
    {
      "file": "products/context/esa-proba-v-4.jpg",
      "alt": "Proba-V on its separation system with clear plates over the solar panel and a gold SATRAM box underneath",
      "long": "Proba-V seen from below and the side, attached to its separation system, with clear plastic plates over the solar panel, cabling and a gold-coloured SATRAM box on its underside.",
      "kind": "product",
      "credit": "ESA - Karim Mellab",
      "license": "ESA Standard Licence",
      "page_url": "https://www.esa.int/ESA_Multimedia/Images/2013/04/SATRAM_payload_aboard_Proba-V"
    },
    {
      "file": "products/context/esa-proba-v-5.jpg",
      "alt": "Proba-V on a black dome-shaped adapter in a launch-site clean room, with two technicians on a lift",
      "long": "Proba-V with dark solar-cell panels mounted on a large black dome-shaped adapter in a launch-site clean room, with two technicians on a lift platform beside it.",
      "kind": "product",
      "credit": "ESA-Karim Mellab",
      "license": "ESA Standard Licence",
      "page_url": "https://www.esa.int/ESA_Multimedia/Images/2013/04/Removing_Proba-V_s_last_covers"
    },
    {
      "file": "products/context/esa-proba-v-1.jpg",
      "alt": "Cloud-free satellite image of Greece taken by Proba-V at 300 m per pixel",
      "long": "A cloud-free image of Greece acquired by Proba-V on 19 July 2015, at 300 m per pixel. It is a mission data product, not a photo of the spacecraft.",
      "kind": "context",
      "context": "Earth image taken by Proba-V",
      "credit": "ESA/Belspo – produced by VITO",
      "license": "CC BY-SA 3.0 IGO",
      "page_url": "https://commons.wikimedia.org/wiki/File:Greece_by_Proba-V_ESA373359.jpg"
    },
    {
      "file": "products/context/esa-proba-v-2.jpg",
      "alt": "Cloud-free satellite image of Belgium taken by Proba-V at 300 m per pixel",
      "long": "A cloud-free image of Belgium acquired by Proba-V on 19 July 2015, at 300 m per pixel, showing land cover and vegetation. It is a mission data product, not a photo of the spacecraft.",
      "kind": "context",
      "context": "Earth image taken by Proba-V",
      "credit": "ESA/Belspo – produced by VITO",
      "license": "CC BY-SA 3.0 IGO",
      "page_url": "https://commons.wikimedia.org/wiki/File:Image_of_Belgium,_acquired_by_ESA%E2%80%99s_Proba-V_satellite.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"
}