Physical properties of near-earth objects: open problems Original Research Article

The current unsatisfactory situation regarding physical characterization of the near-Earth objects (NEO) is briefly reviewed. Different techniques can be used to obtain basic information on NEO sizes and compositions. However, only a few of them can be efficiently applied in practice. The most productive approach is to obtain radiometric observations in the thermal infrared, plus visible and near-infrared spectroscopy or spectrophotometry. A dedicated space-based system is recommended owing to the difficulties in obtaining infrared radiometric observations from the ground. Moreover, with careful thermal design such a system would allow observers to study the particular subset of NEOs (Atens and Inner Earth Objects) that are difficult to observe with ground-based telescopes.