Visible spectral imager for occultation and nightglow (VISION) for the PICASSO Mission

Heikki Saari, Antti Näsilä, Christer Holmlund, Rami Mannila, Ismo Näkki, Harri J. Ojanen, Didier Fussen, Didier Pieroux, Philippe Demoulin, Emmanuel Dekemper, Filip Vanhellemont

    Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

    7 Citations (Scopus)


    PICASSO - A PICo-satellite for Atmospheric and Space Science Observations is an ESA project led by the Belgian Institute for Space Aeronomy, in collaboration with VTT, Clyde Space Ltd. (UK), and the Centre Spatial de Liège (BE). VTT Technical Research Centre of Finland Ltd. will deliver the Visible Spectral Imager for Occultation and Nightglow (VISION) for the PICASSO mission. The VISION targets primarily the observation of the Earth's atmospheric limb during orbital Sun occultation. By assessing the radiation absorption in the Chappuis band for different tangent altitudes, the vertical profile of the ozone is retrieved. A secondary objective is to measure the deformation of the solar disk so that stratospheric and mesospheric temperature profiles are retrieved by inversion of the refractive raytracing problem. Finally, occasional full spectral observations of polar auroras are also foreseen. The VISION design realized with commercial of the shelf (CoTS) parts is described. The VISION instrument is small, lightweight (~500 g), Piezo-actuated Fabry-Perot Interferometer (PFPI) tunable spectral imager operating in the visible and near-infrared (430 - 800 nm). The spectral resolution over the whole wavelength range will be better than 10 nm @ FWHM. VISION has is 2.5° x 2.5° total field of view and it delivers maximum 2048 x 2048 pixel spectral images. The sun image size is around 0.5° i.e. ~500 pixels. To enable fast spectral data image acquisition VISION can be operated with programmable image sizes. VTT has previously developed PFPI tunable filter based AaSI Spectral Imager for the Aalto-1 Finnish CubeSat. In VISION the requirements of the spectral resolution and stability are tighter than in AaSI. Therefore the optimization of the of the PFPI gap control loop for the operating temperature range and vacuum conditions has to be improved. VISION optical, mechanical and electrical design is described.
    Original languageEnglish
    Title of host publicationSensors, Systems, and Next-Generation Satellites XIX
    EditorsRoland Meynard
    Place of PublicationBellingham
    PublisherInternational Society for Optics and Photonics SPIE
    ISBN (Print)978-1-62841-849-1
    Publication statusPublished - 2015
    MoE publication typeA4 Article in a conference publication
    EventSensors, Systems, and Next-Generation Satellites XIX - Toulouse, France
    Duration: 21 Sept 201524 Sept 2015

    Publication series

    SeriesProceedings of SPIE


    ConferenceSensors, Systems, and Next-Generation Satellites XIX
    Abbreviated titleSPIE REMOTE SENSING


    • hyperspectral sensors
    • multispectral image sensors
    • Fabry-Perot Interferometer
    • Piezo actuators
    • imaging spectrometer
    • UAV
    • airborne
    • remote atmospheric sensing


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