I. INTRODUCTION

II. ORBITAL EDGE COMPUTING  
A. Concept of OEC  
B. Satellite Constellations, Networking and Communication  
C. Mobile Computing for IoT: From Ground to Space  
D. Orbital Edge Computing Versus Terrestrial Edge Computing  
E. Advanced Technology in Space  

III. SYSTEMS  
A. Satellite Hardware  
B. Satellite Software  
C. Architecture  

IV. APPLICATIONS  
A. Cases of OEC Applications  
B. Source data from ground  
C. Source data from space  

V. SIMULATORS AND TESTBEDS  
A. Satellite Constellations for Simulation  
B. Experiment Methods  
C. Simulation Tools  

VI. ALGORITHMS  
A. Computation Offloading  
B. Resource Management  
C. Mobility Management  

VII. ISSUES, CHALLENGES AND FUTURE RESEARCH DIRECTIONS  
A. Issues and Challenges  
B. Opportunities and Future Research  

VIII. CONCLUSION