The investigation of near Earth Objects (NEOs) can provide crucial information on the formation and early evolution of the solar system and is also important to constrain the asteroidal contribution to the delivery of prebiotic material (water and organic molecules) to our planet (e.g., Pierazzo and Chyba, 1999; Morbidelli et al., 2000; Saladino et al., 2013; OBrien et al., 2014).
The reserve in water and rare metals held by NEOs is also gaining the attention of government agencies and private companies, as asteroid mining could expand the Earths resource bases in the near future (e.g., Sanchez and McInnes, 2013). Furthermore, NEOs represent a well-known threat to human beings and life in general: in particular, the “potentially hazardous objects” (PHOs, i.e. an object larger than 140m and orbital intersection distance less than 7.5 million km) could in principle collide with the Earth within the next century causing extensive damage (e.g., Perna et al., 2013, 2016).
The proximity of NEOs allows us to study asteroids about two to three orders of magnitude smaller than those observable in the main belt (i.e., down to metre-sized objects), hence opening new frontiers in asteroidal science.
Small-sized (tens/hundreds of metres in diameter) NEOs deserve a special attention also in terms of hazard, as they have the highest statistical likelihood of actually impacting the Earth, still producing catastrophic events at a local/regional scale (e.g., Perna et al., 2015a).
More in general, recent results already evidenced that small asteroids behave differently than the larger bodies in terms of rotational properties (Statler et al., 2013) and regolith generation (Delbo et al., 2014). However, such small asteroids become bright enough to be physically characterized from Earth only for very limited time spans, coinciding with their close approaches with our planet, whereupon they could become unobservable for years or even for decades.
Rapid-response physical observations of such bodies are hence necessary in order to keep up with the present trend of NEO discoveries toward small size objects thus avoiding to leave the characterization rate fall behind the discovery rate.
