The Department Space Instruments is newly founded. It comprises the instrument development activities which previously were distributed across several departments. Major missions with significant contributions of the Institute are ESA’s planetary missions BepiColombo, CHEOPS (Characterising exoplanets satellite), and PLATO (Planetary transits and oscillations of stars). The department conceived and developed the MERTIS IR spectrometer for BepiColombo. It developed the radiometer for HP³ (Heat flow and Physical Properties Package 3) on NASA’s InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission and it develops significant parts of the optical sensors for ESA’s exoplanet missions CHEOPS and PLATO. This is done in close cooperation with DLR’s Institute of Planetary Research. The department also leads the development of the Earth observation spectrometer DESIS, which will be launched in 2018 to the ISS. A special focus is on instrument design and on-board data processing.