While surface spectroscopy has become a routine tool to study planetary composition, a number of questions remain open concerning efficient interpretation of such observations. The goal of the session is to present progresses in numerical methods to extract relevant information from spectroscopy in solid phase, reference laboratory data bases, photometric modeling, and mixing/unmixing methods. Applications will encompass both small bodies and planetary surfaces, and UV to far IR ranges. Applications to Rosetta and Dawn data processing is welcome this year.