 Marco Polo was first rejected in June 2007 for the Cosmic Vision program, but was selected for further assessment studies in November 2007.The "in-situ" investigation and sample analysis would allow to improve knowledge of the physical and chemical properties of a small Near-Earth object (NEO) which is believed to have kept the original composition of the solar nebula in which planets formed.Thus, it would provide some constraints to the models of planet formation and some information on how life ingredients may have been brought to Earth.