Fig. 1. Coverage of spacecraft at different orbital altitudes by NASA's Deep Space Network^[4]

Fig. 2. Coverage of China Deep Space TT&C Network at 10° elevation^[6]

Fig. 3. Schematic diagram of 4×35 m antenna array of China Kashi deep space station^[6]

Fig. 4. Required for data transmission rate in deep space exploration missions^[13]

Fig. 5. Profile of NASA deep space communications capability^[16]（At Jupiter）

Fig. 6. Technical approaches adopted by NASA DSN in the future to improve the data reception rate and the expected effect of improved data transmission capacity^[17]

Fig. 7. Comparison of radio frequency beam and RF beam divergence from Mars toward Earth^[18]

Fig. 8. Block diagram of the deep space laser communication link^[21]

Fig. 9. Average global afternoon cloud cover measured daily by the Aqua satellite between 2002 and 2015^[22]

Fig. 10. Regional distribution of global tropical desert climate

Fig. 11. Example of multi-site optical network designed for mitigation of weather-induced outages^[21]

Fig. 12. Comparison of a single 12 m diameter segmented primary telescope conceptual design (right) and an array of 2.2 m diameter telescopes for an equivalent effective diameter^[19]

Fig. 13. RF/ optical hybrid aperture concepts of DSN 34 m antenna^[23-24]

Fig. 14. NASA "integrated" GEO relay concept^[26]

Fig. 15. NASA super-geosynchronous geostationary relay concept^[27]

Fig. 16. NASA SCaN enhanced deep space domain capabilities^[28]

Fig. 17. Schematic diagram of NASA space communications cognitive network^[29]

Fig. 18. Schematic diagram of 35 m deep space RF/optical hybrid system^[6]

Fig. 19. Distribution of potential deep space optical communication ground sites