TITLE: Efficient Usage of Self Validated Integrators for Space Applications AUTHORS: Elisa M. Alessi, Ariadna Farres, Angel Jorba, Carles Simo, Arturo Vieiro Departament de Matematica Aplicada i Analisi Universitat de Barcelona Gran Via 585 08007 Barcelona, Spain E-mails: elim@maia.ub.es, ari@maia.ub.es, angel@maia.ub.es, carles@maia.ub.es, vieiro@maia.ub.es ABSTRACT: The present report addresses the possibilities offered by validated integrators to deal with some space problems. First, we survey previous results on validated methods for ODEs and we discuss their sharpness and efficiency, keeping in mind their suitability for space-related computations. We have considered two concrete situations. The first one is the propagation of the orbit of a NEO asteroid, starting from data affected by observational error for a moderate time span. We have focused on the concrete case of 99942 Apophis, which is having close approaches to the Earth on the years 2029 and 2037. The goal here is to check if the use of validated methods can be useful to elucidate possible collisions of these objects with the Earth. The second problem considered is the transfer of a probe with low thrust propulsion from parking orbit around the Earth to a much higher orbit, including a capture by the Moon. The goal is to see how the uncertainties in the initial condition and the thrust affect the propagation of the orbit.