Calibration of MAJIS (Moons And Jupiter Imaging Spectrometer): III. Spectral Calibration

TL;DR

This paper details the spectral calibration process of the MAJIS instrument on the JUICE mission, comparing ground calibration results with in-flight data to ensure optimal performance in observing Jupiter's moons.

Contribution

It provides a comprehensive analysis of spectral calibration datasets, deriving spectral response functions and comparing ground and in-flight performances of MAJIS.

Findings

Spectral response functions were successfully derived for the entire field of view.

Ground calibration performances align with in-flight measurements within specified requirements.

Operational parameters like temperature and spectral binning influence spectral characteristics.

Abstract

The Moons And Jupiter Imaging Spectrometer (MAJIS) is the visible and near-infrared imaging spectrometer onboard ESA s Jupiter Icy Moons Explorer (JUICE) mission. Before its integration into the spacecraft, the instrument undergoes an extensive ground calibration to establish its baseline performances. This process prepares the imaging spectrometer for flight operations by characterizing the behavior of the instrument under various operative conditions and uncovering instrumental distortions that may depend on instrumental commands. Two steps of the on-ground calibration campaigns were held at the instrument level to produce the data. Additional in-flight measurements have recently been obtained after launch during the Near-Earth Commissioning Phase. In this article, we present the analyses of these datasets, focusing on the characterization of the spectral performances. First, we describe and analyze the spectral calibration datasets obtained using both monochromatic sources and polychromatic sources coupled with solid and gas samples. Then, we derive the spectral sampling and the spectral response function over the entire field of view. These spectral characteristics are quantified for various operational parameters of MAJIS, such as temperature and spectral binning. The derived on-ground performances are then compared with in-flight measurements obtained after launch and presented in the framework of the MAJIS performance requirements.