Fig. 1. The ADRIOS of ESA^［11-12］

Fig. 2. Diagram of the EAGLE^［13-14］

Fig. 3. The GSSAP satellite of United States Air Force^［15-17］

Fig. 4. Conceptual figure of the S5 satellite^［18-19］

Fig. 5. The Silentbarker satellite^［20-21］

Fig. 6. Conceptual diagram of the Tetra satellite^［22-24］

Fig. 7. SBO camera payloads on a board space-based observation satellite

Fig. 8. Geometric model of space-based radar detection^［33］

Fig. 9. Multi-sensor fusion images^［44］

Fig. 10. Data layer fusion^［45］

Fig. 11. Feature layer fusion^［45］

Fig. 12. Decision layer fusion

Fig. 13. Collaborative close-in observation by multiple spacecrafts

Fig. 14. Strategies for applying deep reinforcement learning algorithms to spacecraft motion planning^［56］

Fig. 15. Architecture of the position-attitude dual-channel feature fusion network^［58］

Fig. 16. Structure of the CNN

Fig. 17. Principle of the GAN^［67］