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Spectrometer for Solar Orbiter calibrated


The large vacuum tank which was conceived for the characterization of space instruments at the Metrology Light Source (MLS).

Solar Orbiter is a spacecraft of the European Space Agency (ESA) which is intended to orbit the Sun for seven years and to provide scientific insights into solar and heliospheric physics. This mission is scheduled to start in October 2018. Its main objective is to observe the so-called space weather, i.e. processes taking place in the solar corona which, due to particle radiation (the "solar wind"), directly influence the Earth's atmosphere. Besides effects such as polar lights, this causes massive disruptions, e.g., in satellite communications and air traffic.

Solar Orbiter will be equipped with six remote-sensing instruments. In the spectral ranges of EUV and VUV (extreme ultraviolet and vacuum ultraviolet), these are the EUV imager (EUI), the SPICE instrument (Spectral Imaging of the Coronal Environment) and an observation channel of METIS (Multi Element Telescope for Imaging and Spectroscopy). PTB is involved in all three of these instruments through calibrations which have been carried out at the Metrology Light Source (MLS). The EUI's flight model has, thus, now been directly calibrated by means of radiometry using the large vacuum tank at the MLS which was conceived specially for such purposes. METIS's VUV detector was previously characterized at the MLS at its working wavelength of 121.6 nm – the scientifically relevant emission wavelength of atomic hydrogen. In contrast, SPICE's final calibration was carried out externally using a hollow cathode discharge source which can be traced to the MLS.

These activities were undertaken in close cooperation especially with the scientific institutions responsible for the construction and the operation of the instruments: the Centre Spatial de Liège (CSL, Liège, Belgium), the Max Planck Institute for Solar System Research (MPS, Göttingen, Germany) and the Rutherford Appleton Laboratory (RAL, Harwell, UK).


A. Gottwald, 7.13, E-Mail: Opens window for sending emailAlexander.Gottwald(at)ptb.de

R. Klein, 7.14, E-Mail: Opens window for sending emailRoman.Klein(at)ptb.de