Mariel Borowitz, Georgia Institute of Technology; Brian Gunter, Georgia Institute of Technology; Megan Birch, Georgia Tech Research Institute; Richard Macke, Georgia Institute of Technology
Keywords: Space Traffic Management, Simulation, Scenarios, Space Debris,
Abstract:
As the number of objects in space has increased in recent years, the number of conjunction warnings has also grown significantly. However, formal guidelines to manage or coordinate responses to these warnings have yet to be adopted. As both industry and government agencies across the globe seek to utilize the near-Earth space environment with a variety of large planned satellite constellations, the total number of resident space objects (RSOs) is projected to increase by a factor of two in the coming decade, with over 20,000 new satellites in LEO and MEO projected to be launched into orbit. This is expected to lead to further increases in the number of potential conjunctions. While mission operators strive to ensure all satellites are operational, a certain percentage of these satellites will fail prematurely, creating inactive RSOs that may stay in orbit for years or decades, creating additional hazards not capable of maneuvering. While guidelines are in place for expected deorbit timelines after a satellite’s end-of-life, e.g., 25 years, there is still no formal or widely accepted maneuver guidelines to ensure that a future crowded LEO and MEO environment can be effectively managed. In the event that a conjuntion is predicted, the current system relies on satellite operators acting independently, with no requirement for action or for coordination with other operators or agencies.
If a set of formal maneuver guidelines were developed and adopted, the hypothesis is the space environment could be well managed and be able to sustain the current growth pattern in new satellites. This leads to the question of what guidelines should be adopted, how would they be implemented, and how would they be enforced or monitored. To begin addressing these questions, this study seeks to explore the impact that various “rules of the road” would have if implemented in future space traffic management policy. A robust simulation environment was developed in which both the current resident space object (RSO) catalog, as well as scenarios involving future mega-constellations, are included and propagated in time to assess the frequency and circumstance (active vs. passive object, small vs. large object, nation of origin, etc.) of predicted collisions. Various collision avoidance guidelines were then implemented to evaluate their effectiveness in terms of both the number of predicted collisions, as well as other metrics, such as fuel costs and safety of maneuver. Simulation parameters included, among others, the number of satellites involved, latencies in maneuver notification, and rate of maneuver compliance. The propagation of the satellite orbits used a full force-model approach, including non-spherical gravity, drag, solar radiation pressure, and 3rd-body effects, and covered simulation time frames spanning from one to six months. While collision avoidance among active satellites can be achieved with 100% compliance among satellite operators, the situation becomes more nuanced as various scenarios are explored when both participation and lead times are varied, and when the maneuvering satellite is determined through a priority ranking, e.g., with lower-priority satellites assuming a larger role in the maneuver. An assessment of purely inactive RSO collisions is also considered to determine the overall impact of these objects on the set of active RSOs, and to the overall priority that mitigation of these inactive objects should have on the space traffic management policies adopted. The presentation will provide an overview of the simulation environment and guidelines evaluated, as well as a summary of the policies and scenarios that were determined to be the most effective.
Date of Conference: September 14-17, 2021
Track: Conjunction/RPO