MERCURY In-flight calibration of the PHEBUS UV instrument and Monte Carlo modelling of the hydrogen exosphere

摘要: A unique feature of Mercury's space environment is its strongly coupled surface-exosphere-magnetosphere-solar wind system, which can be remotely monitored by missions such as Mariner 10, MESSENGER and soon BepiColombo ground-based observatories. exosphere a very complex medium with only few species detected so far, including atomic hydrogen. H has been once 10 in 1974-1975 represents tracer the interaction between solar Mercury. The PHEBUS instrument onboard ESA/JAXA mission to Mercury dual-channel EUV-FUV spectrometer capable detecting faint emissions I Lyman- at 121.6 nm. first part this thesis focuses on radiometric modelling simulation optical return PHEBUS. To prepare for in-flight orbit spectral calibrations, set reference stars determined evaluated match resolution range detector. Predictions possibility detection wide emission lines are given (science performance). based SPICAV, UV Venus Express use similar techniques perform relevant calibrations. Therefore, study star occultation events SPICAV performed second thesis. stars' spectra extracted, analysed convoluted function future results stored calibration database "Cross-calibration past FUV experiments" workgroup ISSI. In parallel development new dedicated instruments, high sensitivity resolution, state-of-the-art simulations also needed. third 3D Monte Carlo hydrogen model SPERO constructed. fully consistent exospheric Mercury, taking into account source loss mechanisms thermal desorption, photoionisation radiation pressure. Thermal desorption assumed dominant Surface densities well densities, temperatures velocities computed up 8 radii. carried out highlighting uncertainties mechanisms, resulting day/night density temperature asymmetry. Using radiative transfer makes it possible compare data later possibly MASCS NASA MESSENGER.