The Capacity of Low Earth Orbit Computed using Source-sink Modeling

TL;DR

This paper introduces a novel source-sink model, MOCAT-3, to estimate the maximum sustainable number of satellites in Low Earth Orbit, considering stability, failure rates, and future traffic demands.

Contribution

The paper develops a new multi-shell multi-species source-sink model and defines orbital capacity based on system equilibrium, providing a quantitative estimate for LEO's satellite capacity.

Findings

Estimated maximum LEO capacity is about 12.6 million satellites at 7% failure rate.

The model assesses future traffic compatibility and proposes strategies for accommodating satellite constellations.

A new definition of orbital capacity based on stable equilibrium points is introduced.

Abstract

The increasing number of Anthropogenic Space Objects (ASOs) in Low Earth Orbit (LEO) poses a threat to the safety and sustainability of the space environment. Multiple companies are planning to launch large constellations of hundreds or thousands of satellites in the near future, increasing congestion in LEO and the risk of collisions and debris generation. This paper employs a new multi-shell multi-species evolutionary source-sink model, called MOCAT-3, to estimate LEO orbital capacity. In particular, a new definition of orbital capacity based on the stable equilibrium points of the system is provided. Moreover, an optimization approach is used to compute the maximum orbital capacity of the low region of LEO (200-900 km of altitude), considering the equilibrium solutions and the failure rate of satellites as a constraint. Hence, an estimate for the maximum number of satellites that it is possible to fit in LEO, considering the stability of the space environment, is obtained. As a result, considering 7% of failure rate, the maximum orbital capacity of LEO is estimated to be about 12.6 million satellites. Compatibility of future traffic launch, especially in terms of satellite constellations, is also analyzed and a strategy to accommodate for future traffic needs is proposed.