The Sentinel-5 Precursor mission is a single-payload satellite in a low Earth orbit to be launched in summer 2017. The mission will provide daily global information on trace gases and aerosols important for air quality, climate forcing and the ozone layer. The only payload of the mission is the TROPOMI instrument which is a nadir push-broom spectrometer measuring in the ultraviolet, visible, near-infrared and the shortwave infrared. The selected wavelength range allows for the observation of key atmospheric constituents including O₃, NO₂, CO, SO₂, CH₄, CH₂O, aerosols and clouds. In this special issue, scientific and operational algorithms are described and verified, which have been developed to derive the various data products from the mission.