Escape of ejecta from cratered Solar System satellites

The effect of craters on the variation of the escape velocity over the surface of spherical and ellipsoidal satellites is investigated. Three-dimensional numerical models are used and several factors - planetary tides, satellite rotation and non-spherical shape - are included. It is found that in most cases craters have considerable effects only in their vicinity. However, in the case of Phobos the morphology of the satellite and the variation of the escape velocity over its surface are significantly affected by the presence of crater Stickney. (author)