 Secondary crater sizes and morphology also are affected by the distribution of rock sizes in the regolith of the target body.The calculation of depth of secondary crater can be formulated based on the target body's density.Studies of the Nördlinger Ries in Germany and of ejecta blocks circling lunar and martian crater rims suggest that ejecta fragments having a similar density would likely express the same depth of penetration, as opposed to ejecta of differing densities creating impacts of varying depths, such as primary impactors, i.e.