Exploring the solar system: the view of planetary surfaces with VIS/IR remote sensing methods

The structure of planetary surfaces unveils basic formation processes and evolution lines of different objects in the solar system, and often the view on the top of a planet is the only available information about it. Advanced remote sensing technologies on deep space missions are aimed at accessing a maximum of relevant data to characterize a planetary object holistically. This approach requires concert strategies in planetary and engineering science. In this framework VIS/IR spectroscopic remote sensing methods are key technologies for imaging planetary atmospheres and surfaces, for studying their composition, texture, structure and dynamics. Basing on these analyses it succeeds to observe the single objects in more global geo-scientific content. The paper focuses on main geo-scientific output coming from spectroscopic studies of planetary surfaces in conjunction with their interiors, atmospheres, and the interplanetary space. It summarizes selected results of spectral studies onboard of the ESA deep space missions BepiColombo, Venus Express, Mars Express, and Rosetta. The corresponding spectral instruments are introduced. The complex conflation of special knowledge of the disciplines planetology, optical and IR measuring techniques, and space flight engineering is demonstrated in several examples. Finally, the paper gives an outlook of current developments for spectral studies in planned missions, and sums up some of the driving questions in planetary science.