The data format of the MErcury Radiometer and Thermal Infrared Spectrometer (MERTIS) onboard BepiColombo

The MErcury Radiometer and Thermal Infrared Spectrometer (MERTIS) is an instrument to study the mineralogy and temperature distribution of Mercury's surface in unprecedented detail. During the nominal mission, MERTIS will map the whole surface at 500 m scale, combining a push-broom IR grating spectrometer (TIS) with a radiometer (TIR) sharing the same optics, instrument electronics, and in- ight calibration components for the wavelength range of 7-14 μm (TIS) and 7-40 μm (TIR). MERTIS observed the Moon in April 2020 and Venus in October 2020 under conditions different from nominal operation and performed surprisingly well. MERTIS returned several hundreds of thousands scientifically useful spectra from the two campaigns. MERTIS archival data are stored in Planetary Data System v4 format (PDS4), that describes 2 physical formats for each MERTIS channel. Each channel will is stored in Flexible Image Transport System (FITS) and in pure ASCII, to maximize both machine and human readability.