When a micro-debris or a micrometeoroid impacts a spacecraft surface, secondary particles, called ejecta, are produced. These ejecta can contributes to a modification of the debris environment: either locally by the occurrence of secondary impacts on the components of complex and large space structures, or at great distances by the formation of a population of small orbital debris. This paper describes, firstly, the ejecta production, and secondly, their lifetime and orbit propagation. Then, the repartition of ejecta in LEO is given. Results describing the ejecta number as a function of size and altitude are presented.