The Bepi-Colombo mission was launched in October 2018, headed for Mercury. This mission is a collaboration between Europe and Japan. It is dedicated to the study of Mercury and its environment. It will be inserted into Mercury orbit in December 2025 after a 7-year long cruise. Probing of Hermean Exosphere By Ultraviolet Spectroscopy (PHEBUS) is an ultraviolet Spectrograph and is one of the 11 instruments on-board the Mercury Planetary Orbiter (MPO). It is dedicated to the study of the exosphere of Mercury, its composition, dynamics and variability and its interface with the surface of the planet and the solar wind. The PHEBUS instrument contains four distinct detectors covering the spectral range from 55 nm up to 315 nm and two additional narrow windows at 404 nm and 422 nm. It also has a one-degree of freedom mechanism that allows observations along a cone with an half angle of 80 ∘ $80^{\circ }$ . This paper follows a detailed presentation of the PHEBUS instrument design that was presented by Chassefière et al. (Planet. Space Sci. 58:201–223, 2010 ). Here we present an update of the science objectives and measurement requirements following the results published by the MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) mission. We also present results of the ground calibration campaigns of the flight unit that is currently on-board MPO. In the last part, we present some details of the observations that will be performed during the cruise to Mercury, such as stellar observation campaigns, interplanetary background observations and planetary flybys.

中文翻译：

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Bepi-Colombo 上的 PHEBUS：发射后更新和仪器性能

Bepi-Colombo 任务于 2018 年 10 月发射，前往水星。该任务是欧洲和日本之间的合作。它致力于研究水星及其环境。经过7年的巡航，它将于2025年12月插入水星轨道。紫外光谱仪 (PHEBUS) 探测赫尔米外逸层是一种紫外光谱仪，是水星行星轨道器 (MPO) 上的 11 台仪器之一。它致力于研究水星的外逸层、它的组成、动力学和可变性，以及它与行星表面和太阳风的界面。PHEBUS 仪器包含四个不同的检测器，涵盖从 55 nm 到 315 nm 的光谱范围和两个额外的 404 nm 和 422 nm 窄窗口。它还具有单自由度机制，允许沿半角为 80 ∘ $80^{\circ }$ 的锥体进行观察。本文详细介绍了 Chassefière 等人提出的 PHEBUS 仪器设计。(Planet. Space Sci. 58:201–223, 2010)。根据汞表面、空间环境、地球化学和测距 (MESSENGER) 任务发布的结果，我们在此介绍了科学目标和测量要求的更新。我们还介绍了当前机载 MPO 飞行单元的地面校准活动的结果。在最后一部分，我们将介绍将在水星巡航期间进行的观测的一些细节，例如恒星观测活动、行星际背景观测和行星飞越。