Calibration pipeline of VIS-NIR imaging spectrometers for planetary exploration: The rosetta VIRTIS-M case

The capability of spaceborne VIS-NIR imaging spectrometers devoted to planetary exploration to acquire valuable scientific datasets largely depends on the accuracy of the calibration pipeline. In this paper we discuss about the method currently used to calibrate the flight data of VIRTISM (Visible InfraRed Thermal Imaging Spectrometer, Mapping Channel) on board the ESA Rosetta mission to comet 67P/Churyumov-Gerasimenko. By using both prelaunch characterization measurements and in-flight observations of well-known astronomical targets (acquired during two flybys of the Earth and one of Mars), we have built a pipeline able to convert raw engineering units (DN/s) in physical units (spectral radiance Wm−2µm−1sr−1 or reflectance I/F). This methodology and the resulting scientific data are discussed in detail.