A comparison of debris environment projections using the evolve and chain models

Abstract

EVOLVE and CHAIN are two models for debris environmen, projections that have been developed independently using very different conceptual approaches. A comparison of results from these two models therefore provides a means of validating debris environment projections which they have made. EVOLVE/1/ is a model that requires mission model projections to describe future space operations; these projections include launch date, mission orbit altitude and inclination, mission duration, vehicle size and weight, and classification as an object capable of experiencing breakup from on-board stored energy. EVOLVE describes the orbital debris environment by the orbital elements of the objects in the environment. CHAIN /2,3/ is an analytic model that bins the debris environment in size and altitude rather than following the orbit evolution of individual debris fragments. The altitude/size bins are coupled by the initial spreading of fragments by collisions and the following orbital decay behavior. A set of test cases covering a variety of space usage scenarios have been defined for the two models. In this paper, a comparison of the results will be presented and sources of disagreement identified and discussed. A sensitivity analysis of the most important model components will be performed using both models.