Basic targeting strategies for rendezvous and flyby missions to the near-Earth asteroids

Missions to asteroids and comets are becoming increasingly feasible both fr om a technical and a financial point of view. in particular, those directed towards the Near-Earth Asteroids have proven suitable for a low-cost appro ach, thus attracting the major space agencies as well as private companies. The choice of a suitable target involves both scientific relevance and mis sion design considerations, being often a difficult task to accomplish due to the limited energy budget at disposal. The aim of this paper is to provi de an approach to basic trajectory design which allows to account for both aspects of the problem, taking into account scientific and technical inform ation. A global characterization of the Near-Earth Asteroids population car ried out on the basis of their dynamics, physical properties and flight dyn amics considerations, allows to identify a group of candidates which satisf y both, the scientific and engineering requirements. The feasibility of ren dezvous and flyby missions towards them is then discussed and the possibili ty of repeated encounters with the same object is investigated, as an inter mediate scenario. Within this framework, the capability of present and near future launch and propulsion systems for interplanetary missions is also a ddressed. (C) 2001 Elsevier Science Ltd. All rights reserved.