Defining orbital debris environmental conditions for spacecraft vulnerability assessment

The major problem that orbital debris presents to a particular space structure is not that of catastrophic collision, which fragments the structure, but rather the threat of collisions with small debris that will damage it. In this paper, a method is developed for defining the debris environment to support the analysis of vulnerability of space structures. Flux directionality functions related to spacecraft surface degradation, which are seen to be various velocity moments of the phase space debris density distribution, are derived for both the man-made debris environment and for a simple model of the meteoroid environment. A method for accounting for the shielding of spacecraft surfaces by other spacecraft components is also presented within the flux directionality context.