Lessons learned from the comparison of EVOLVE and CHAIN

Abstract

EVOLVE and CHAIN are two models for the projection of the orbital debris environment. They were developed independently using very different conceptual approaches. Consequently, their comparison has proven to be valuable for validating the debris environment projections for both programs. The project to use EVOLVE and CHAIN to validate one another and to develop a complementary use of the two codes has been documented in a series of papers. The early papers in this series were focused on a comparison of results for environment projections over the next 100 years. These comparison produced relatively minor changes (and improvements) in both programs that could be explained by conceptual differences designed into the original codes. Later papers in the series focused on using EVOLVE to establish rate coefficients to be used by CHAIN for longer term environment projections. In this paper we will review the new understandings that have resulted from these efforts. We will also extend the work on establishing an improved method for using EVOLVE to set conditions for long-term CHAIN environment projections and use this new work to begin investigating the sensitivity of the environment projections to aspects of collisional breakup models that currently are, and in the foreseeable future will continue to be, severely short of data.