colloquium Ettore Perozzi – The Asteroid Hazard: from Awareness to Operations

Over the last 30 years, monitoring the NEO (Near-Earth Object) population has undergone a change of
paradygm. Started as a research activity mainly focussed in investigating the challenging dynamical
behaviour of these small solar system bodies (needing high-accuracy orbit determination, close encounter
modelling, impact monitoring), it is now carried out routinely by dedicated centers at agency level (e.g. the
NASA and ESA Planetary Defence Offices). The NEAR rendezvous with Eros (February 2000) inaugurated the
in-situ exploration of NEOs which, to date, encompasses sample return missions and the successful
Dart/LICIAcube deflection experiment. Infrared orbiting obervatories are planned for further fostering the
NEO discovery rate. Finally, the asteroid hazard has attracted the growing concern of governmental
intitutions, which have established their own programmes and roles, reaching up to the United Nations
(UNOOSA) for global coordination. The transition to a ground- and space-based operational system is
therefore nearing. Within this framework, the (sometimes difficult) interaction between the many souls of
Planetary Defence – science, technology, civil protection, commercial exploitation – is discussed in an
historical perspective.