The Ariel payload: design progress and structural model outcomes

The Ariel space mission will characterize spectroscopically the atmospheres of a large and diverse sample of hundreds of exoplanets. Ariel is an ESA Medium class science mission (M4) with a Payload provided by a consortium of national funding agencies in ESA member states, plus contributions from NASA, the CSA and JAXA. The payload is based on a 1-meter class telescope operated at below 60K, built all in Aluminium, which feeds two science instruments; a multi-channel guider, photometer and low-resolution spectrometer instrument (the FGS) and a medium resolution spectroscopy instrument (AIRS). This paper provides an overview of the design of the overall payload for the Ariel mission, with a focus on the design updates of the Payload since the payload PDR in 2023, along with the outcomes and lessons learnt from the build of the payload module Structural Model (pSM) in 2025 and the mechanical environmental testing of this pSM in Q1 2026.