A SPECTROMETRIC DEVICE TO MEASURE SPECIES CONCENTRATION CLOSE TO THE SURFACE DURING RE-ENTRY

摘要

An innovative approach to measure the effects of heterogeneous catalysis during re-entry has been proposed for the instrumentation planned for the ESA-EXPERT mission. The goal is to measure the recombination coefficient during the EXPERT re-entry mission by measuring gas species close to the surface. The main elements of the diagnostic system are: a light capturing device and a multi-channel spectrometer. A sapphire pole is used to look directly at the surface during re-entry. The multi-channel spectrometer has 24 channels and a spectral resolution of 0.25 nm/pixel. By knowing the spectral emissions of species such as O, N and their molecules, including NO, it will be possible to determine the presence and concentration of these species. The recombination coefficient will be calculated by applying the kinetic model of Bruno et al for heterogeneous catalysis. The surface heat flux must to be known to perform these calculations, and will eventually be provided by other EXPERT measurements. A preliminary test to validate the feasibility of the device has been planned: comparison between the spectra obtained by PARADE code, using the CFD results obtained by CIRA in condition of max heat flux and the spectra measured by the light capturing device and generated by the 1200KW VKI induction Plasmatron will be performed to the purpose.