Direct simulation of meteoroids and space debris flux on LDEF spacecraft surfaces

The meteoroid flux on all faces of the long duration exposure facility (LDEF) is predicted by a direct simulation Monte Carlo (DSMC) model, which for the first time provides a self-consistent method to model the collision behaviour between both meteoroids and debris with oriented spacecraft surfaces. This new model includes the modified Divine's meteoroid population, and Taylor's velocity distribution, to include the effects of planetary shielding and gravitational enhancement by the Earth. Results obtained when only meteroid impact is considered show good agreement with observed data and provide some correlation with previous models. When the space debris population is also included, the total particle flux on different faces of LDEF fits well with the observed measurements. Information concerning Earth shielding, gravity capturing and atmospheric effects can be obtained by comparing the ratio of the number of meteoroids moving towards the Earth to the total number of the meteoroids, obtained from the DSMC model with measured data. Approximately 25% of the meteoroids flux is predicted as not returning into the interplanetary space due to these effects.