Foreword 3

Executive summary 4

Introduction 5

1 Understanding the debris landscape 6

1.1 Understanding the model 8

1.2 Phases and uncertainties 9

1.3 Translating population into risk 9

2 Economic impact of inaction 10

2.1 Understanding the range 13

2.2 Possible futures for debris costs 15

2.3 Understanding the impact of debris 16

3 Forging a path forward 17

3.1 Technology 18

3.2 Economy 19

3.3 Law and policy 21

3.4 Diplomacy 22

Conclusion 23

Appendix A 24

Appendix B 25

　B1 Mathematical formulation (orbital population model) 25

　B2 Core modelling assumptions 26

　B3 Modelled clusters and event probabilities 27

Appendix C 28

Appendix D 30

Contributors 31

Endnotes 33