With the increasing frequency of human space activities, there are surviving debris of re-entry spacecraft and debris that impact the Earth's surface, causing typical damage cases and affecting the future technological development of spacecraft. Firstly typical re-entry damage cases and disposal methods of foreign spacecraft that have attracted significant social attention are analyzeds. Secondly the main international norms and standards for re-entry casualty risk are introduced. Then those assessment methods of re-entry casualty risk are studied together with re-entry risk analysis tools of NASA and ESA. Finally it's looked forward to the furture development and existing problems of major space powers in the technical directions of active deorbit, assisted deorbit, large-scale reentry, and reusable spacecraft. Research shows that although the re-entry casualty risk of spacecraft and debris is still difficult to predicte very accurately, it is expected to be moderately controlled by the design of risk-reduction measures along with technological development.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |