ORDEM 3.0 and MASTER-2009 modeled debris population comparison

Abstract

The latest versions of the two premier orbital debris engineering models, NASA׳s ORDEM 3.0 and ESA׳s MASTER-2009, have been publically released. Both models have gone through significant advancements since inception, and now represent the state-of-the-art in orbital debris knowledge of their respective agencies. The purpose of these models is to provide satellite designers/operators and debris researchers with reliable, and timely, estimates of the artificial debris environment in -Earth orbit, from about 200 km through about 40,000 km. The small debris environment within the “critical size range” of 1cm to 1mm is of particular interest to both human and robotic spacecraft programs. These objects are much more numerous than larger trackable debris and are still large enough to cause significant, if not catastrophic, damage to spacecraft upon impact. They are also small enough to elude routine detection by existing observation systems. Without reliable detection the modeling of these populations has always coupled theoretical origins with supporting observational data in different degrees.This paper offers the first cooperative comparison of the latest versions of the two models. No attempt to review model internal populations, or compare subsystems, or supporting data sets is made at this time. The models are simply run in the “Spacecraft Mode” for four test cases representing four orbital regimes, ISS (International Space Station orbit), SSO (sun synchronous orbit), GTO (geosynchronous transfer orbit), and GEO (geosynchronous orbit). Specific satellites are chosen within those categories for the analysis. Debris cumulative fluxes at three debris sizes (1m, 10cm, and the critical size range of 1cm to 1mm) are compared. At 1m there is a very good match between ORDEM 3.0 and MASTER-2009 fluxes in the non-GEO orbits, less so in the GEO orbit. The 10cm fluxes do not match as well, indicating possibly different treatment of uncatalogued objects. Within the critical size range it is noted that ORDEM 3.0 flux overtakes that of MASTER-2009 as debris size decreases in all test cases.In the analysis of separate model populations, the disparate usage of debris source populations (MASTER-2009) versus debris material density populations (ORDEM 3.0) is presently unresolved. MASTER-2009 populations of SRM (solid rocket motor) slag and explosion and collision fragments dominate with lower populations of ejecta debris. ORDEM 3.0 populations are dominated by medium and high density material with minor low density material populations. Undoubtedly, more in-depth collaborations will follow to hone in on population differences and sources.