Meteosat Third Generation Sounder (MTG-S) – Status of Spacecraft and Payload Development

Meteosat Third Generation (MTG) is a joint programme of the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) and the European Space Agency (ESA). Its purpose is to ensure the continuity and enhance the quality of geostationary meteorological observations currently provided by its predecessor, Meteosat Second Generation (MSG). The MTG space segment, developed under ESA leadership, consists of two kinds of geostationary satellites: an imager (MTG-I) and sounder (MTG-S) variant. The first MTG-I satellite was launched on December 13, 2022, with start of operational service expected in Q2 2024. The first MTG-S satellite is in the final stages of testing, and currently planned to launch by Q2 2025. Differently from MSG and MTG-I, the principal payload of MTG-S (Infrared Sounder; IRS) is an imaging Fourier transform spectrometer. This paper presents MTG-S and the IRS instrument, with a particular focus on the current state of development and testing.