Optical design and performance verification of Herschel-HIFI

This thesis deals with the verification, characterization and calibration of the optical performance of Herschel-HIFI. The Herschel Space Observatory, an ESA cornerstone mission operational from 2009 to 2013, was and is an important step in exploring the submillimeter and far-infrared universe, in a wavelength regime which is difficult to access. The Heterodyne Instrument for the Far-Infrared (HIFI) onboard the Herschel Space Observatory has shown to work very well in taking high spectral resolution observations of a large variety of astronomical objects, and has already made many important discoveries. The scientific performance of HIFI was intimately connected to realizing the best possible optical performance. An important part of this thesis research was to verify the optical design and performance of Herschel-HIFI by the development and application of novel experimental characterization and calibration techniques, on the ground prior to launch, as well as in-orbit. This led to excellent optical performance of the instrument, in particular at the high-frequency end of HIFI’s spectral range. Moreover, the accurate experimental data, collected during measurements on the ground, were key to help interpreting and guiding the observations in space, and proved significant to the calibration and subsequent scientific success of HIFI.