This paper reports the latest study on a debris index and orbital capacity. Research and Development Directorate in JAXA has been studying debris indexes which can assess the environmental impact of a target object. A previous study proposed index formulas and two processes that should be followed to establish an index. This paper firstly verifies whether the proposed indexes can evaluate the impacts of fragmentations using a unified background environment, i.e., the mass, area of each object, and the number of objects in each altitude band are the same value. The correlation between the total index in each altitude band and the environment evolution will be assessed through some numerical simulations using a debris environment evolutionary model. This study secondly summarizes the trend of orbital evolution at different altitudes in LEO and clarifies what should be considered in orbital capacity. The correlation between a debris index and orbital capacity is also discussed.
Harada et al. (Thu,) studied this question.