AIRS: ARIEL IR Spectrometer development and testing towards the flight model
Abstract
AIRS is the infrared spectroscopic instrument of ARIEL: Atmospheric Remote‐sensing Infrared Exoplanet Large‐survey mission adopted in November 2020 as the Cosmic Vision M4 ESA mission and planned to be launched in 2032 by an Ariane 6 from Kourou toward a large amplitude orbit around L2 for a 4 years mission. Within the scientific payload, AIRS will perform transit spectroscopy of over 1000 exoplanets to complete a statistical survey, including gas giants, Neptunes, super-Earths and Earth-size planets around a wide range of host stars. All these collected spectroscopic data will be a major asset to answer the key scientific questions addressed by this mission: what are exoplanets made of? How do planets and planetary systems form? How do planets and their atmospheres evolve over time? The AIRS instrument is based on two independent channels covering 1.95-3.90 μm (CH0) and 3.90-7.80 μm (CH1) wavelength ranges with prism-based dispersive elements producing spectra of low resolutions R>100 in CH0 and R>30 in CH1 on two independent detectors. The spectrometer is designed to provide Nyquist-sampled spectrum in both spatial and spectral directions to limit the sensitivity of measurements to the jitter noise and intra pixels pattern during the long (10 hours) transit spectroscopy exposures. A full instrument overview will be presented covering the development of the avionic and the engineering models, whose AIRS Cold Unit EM is considered at instrument-level as qualification model. The environmental tests are thus presented at sub-system and instrument level as well as the calibration strategy performed on the detection chain, optical benches and finally the complete instrument with the aim to measure the performances of the AIRS instrument and validate all the ground support equipment. All these programs thus conduct to the realization of the flight model of the instrument foreseen in 2028.