Metis coronagraph - Flight Model under acceptance tests

METIS, an inverted-occultation coronagraph, is one of the most relevant remote sensing instruments of the Solar Orbiter mission of the European Space Agency (ESA). METIS is the only coronagraph ever designed to acquire simultaneous images of the solar corona in two different wavelengths (visible light between 580 nm and 640 nm, and the Lyman- line of Hydrogen at 121.6 nm). The visible channel also includes a polarimeter to observe the linearly polarized component of the K corona. The Qualication Reviews of the coronagraph under responsibility of the Italian industries OHB-I and TAS-I and of the visible and ultraviolet light detector assemblies (VLDA and ULDA) developed by the Max Planck Institute for Solar System Research in Goettingen, Germany, were successfully concluded in 2016. The main optics, in particular the mirrors that are under the responsibility of the Astronomical Institute of the Academy of Sciences of the Czech Republic are also qualied at sub-system level. The main elements (UVDA, VLDA, Mirrors, Polarimeter, etc.) are nally integrated in the coronagraph along with the Processing and Power Unit, High Voltage Unit and Camera Power Converter in the TAS-I facility in Turin. The entrance of the telescope is equipped with sealing protection cap, designed under the responsibility of the Spanish company SENER to be compliant with the very stringent and challenging contamination requirements and to be ejected once in orbit. The vibrations and thermal-vacuum acceptance tests for the Flight Model of the integrated system are successfully completed. After the EMC acceptance tests, the activities of verification and calibration of the instrument will be carried out by the METIS Industrial and Scientific Team under the responsibility of the Principal Investigator, Prof. E. Antonucci.