The NEO Physical Observations and Properties Simulation (NEOPOPS) is a project, financed by the European Space Agency (ESA) and led by INAF - OAR (Observatory of Rome) dedicated to the physical characterization of Near-Earth Objects (NEOs). The project, started in February 2025, will be completed by August 2028, and it is built upon the legacy of prior large programs financed by the EU commission (NEOShield-2, NEOROCKS) devoted to the comprehension and the physical characterization of the NEO population. Those past surveys have made clear that only a joint effort is able to address the current major issues related to NEO impact monitoring and mitigation. In particular, extensively coordinated scientific research and innovative technical developments are necessary to improve our knowledge of the physical nature of small NEOs (the ones with the highest statistical likelihood to impact our planet in the next centuries) and to significantly reduce the risk of unannounced impacts. Therefore, the main objective of the NEOPOPS program is to tackle this scenario, providing a radically new approach:organise follow-up astronomical observations of NEOs efficiently, in order to obtain high-quality data to derive their physical properties, giving priority to timely addressing potentially hazardous asteroids (PHAs) and potential impactors; improve dramatically the statistical analysis, modelling and computer simulations to better understand the physical nature of NEOs. This would be of uttermost importance, for designing effective mitigation measures; foster European and international cooperation on NEO physical characterization, providing scenarios and roadmaps, with the potential to scale-up at a global level the experience gained during the project; cooperate with ESA to significantly enhance public understanding and perception of the asteroid hazard, counteracting the spreading of fake news and unjustified alarms.