当前对于火星进入、下降与着陆过程(entry,descent and landing,EDL)气动环境认知不足,任务风险高。在EDL系统上搭载传感仪器进行飞行数据测量,重建火星大气和气动热环境,并开展充分全面的地面验证是验证科学设计工具和降低未来火星EDL...当前对于火星进入、下降与着陆过程(entry,descent and landing,EDL)气动环境认知不足,任务风险高。在EDL系统上搭载传感仪器进行飞行数据测量,重建火星大气和气动热环境,并开展充分全面的地面验证是验证科学设计工具和降低未来火星EDL任务风险的有效途径,对任务成功与否至关重要。本文首先回顾了人类火星探测任务的发展历程,明确设置热防护传感系统的必要性;然后系统总结了美国两次火星着陆任务MSL、Mars 2020,欧洲ExoMars2016任务和中国天问一号任务所搭载的EDL热防护传感系统的体系构成,以及为满足任务要求,如何进行仪器选择与布局;归纳了4次任务飞行数据的重建方法、关键技术和结果结论;最后给出了EDL热防护传感系统总结的经验、面临的技术难题和未来发展建议。展开更多
The coefficient of thermal expansion, thermal diffusivity and specific heat of C/C composites from room temperature to ultra high temperature were experimentally investigated. Thermal conductivity and thermal stress r...The coefficient of thermal expansion, thermal diffusivity and specific heat of C/C composites from room temperature to ultra high temperature were experimentally investigated. Thermal conductivity and thermal stress resistance of the composites were therefore computed based on experimental results. The results show that the composite has a very low thermal expansion coefficient. Thermal diffusivity decreases exponentially with temperature increase. The specific heat increases linearly as the temperature rises, and the variation trend of thermal conductivity is similar to that of thermal diffusivity. The thermal stress coefficient of C/C composite has little change with temperature variation, and thermal stress resistance of the composite at high temperature is stable.展开更多
文摘当前对于火星进入、下降与着陆过程(entry,descent and landing,EDL)气动环境认知不足,任务风险高。在EDL系统上搭载传感仪器进行飞行数据测量,重建火星大气和气动热环境,并开展充分全面的地面验证是验证科学设计工具和降低未来火星EDL任务风险的有效途径,对任务成功与否至关重要。本文首先回顾了人类火星探测任务的发展历程,明确设置热防护传感系统的必要性;然后系统总结了美国两次火星着陆任务MSL、Mars 2020,欧洲ExoMars2016任务和中国天问一号任务所搭载的EDL热防护传感系统的体系构成,以及为满足任务要求,如何进行仪器选择与布局;归纳了4次任务飞行数据的重建方法、关键技术和结果结论;最后给出了EDL热防护传感系统总结的经验、面临的技术难题和未来发展建议。
文摘The coefficient of thermal expansion, thermal diffusivity and specific heat of C/C composites from room temperature to ultra high temperature were experimentally investigated. Thermal conductivity and thermal stress resistance of the composites were therefore computed based on experimental results. The results show that the composite has a very low thermal expansion coefficient. Thermal diffusivity decreases exponentially with temperature increase. The specific heat increases linearly as the temperature rises, and the variation trend of thermal conductivity is similar to that of thermal diffusivity. The thermal stress coefficient of C/C composite has little change with temperature variation, and thermal stress resistance of the composite at high temperature is stable.
