Typically, surface orientations and the spacecraft velocity vector as well as velocity distributions of space debris and meteoroids are considered for the calculation of fluxes.
A preliminary analysis conducted on a lower level of complexity can be useful in particular when several design iterations steps are expected. In this case, a constant impact velocity of 10 km s-1 for space debris and of 20 km s-1 for meteoroids as well as a constant impact angle of 45 degrees from the surface normal are useful assumptions. These simplified assessments usually agree with a fully 3-D analysis to within a factor 2 for impact fluxes and a factor 5 for the number of impact damages.