Simulating Active Debris Removal Missions

Protecting the space environment is important for ensuring the future of space activity. Debris impacts and an increasing number of collision avoidance manoeuvres will affect all space activity, for example through financial con-sequences or loss of services. It is widely understood that active debris removal is needed to address the increasing debris population. Debris mitigation can limit the number of new objects, but threats are still posed by the existing derelict population. Previous analysis has shown positive outcomes from removing these objects from orbit, however these findings are based on simulations modelling such objects being removed from the environment instantaneously. This analysis therefore misses a crucial part of such missions, by not accounting for how the removal will be conducted. Hence this research will perform a more accurate analysis of debris removal, by accounting for mission failures and their impact upon the environment. As such this will provide a more realistic cost-benefit analysis than those previously performed. A novel Python based simulation has been built to model proposed concepts of operations of active debris removal missions. This is based on probability density functions which model satellite reliability; quantifying the correspond-ing failure rates of the spacecraft subsystems. Monte Carlo simulation then provides information of how often mission failure is likely to occur, and at what stage of operation, giving insight into the potential consequences of failures. This research is expected to show that there are certain key stages where failure is most likely to occur, allowing insight on how these missions can be conducted in the most beneficial manner. This will aid future mission design by helping to identify the causes of failures, and addressing them before they occur in real time, and by minimising the harmful side effects of failed debris removal missions. These harms include failed vehicles becoming part of the derelict population or debris creation from collisions. This work represents the beginning of a wider study aiming to perform a comprehensive cost-benefit analysis of active debris removal, moving beyond work previously published by NASA but encapsulating consequences of real world debris removal. It will therefore recognise the value of debris removal to the environment, while also ensuring such missions are conducted to maximise the benefits and reduce the harms wherever possible.