月面钻进真空环境模拟装置的设计与验证

Design and verification of vacuum environmental simulation device for lunar surface drilling

探月工程(三期)项目提出了在月面进行至少2 m深度的钻取采样任务,前期需要在地面进行模拟月面钻进过程热特性的研究,为此本文发明了一套月面真空环境模拟装置。根据模拟月壤钻进试验的要求,设计了一种可从底部抽气的三段式可多次拆装的真空罐结构。考虑到模拟月壤的颗粒大小和快速抽真空的要求,设计了一种筛网状具有多层过滤结构的月壤筒。根据在真空度不变的条件下可进行连续多次钻进试验的要求,设计了可从外部操作的具有缺齿结构的月壤筒转动机构。由真空度要求和可耐粉尘的特性要求,选取了三级扩散泵组。实验表明,在不放置模拟月壤的情况下,本环境模拟装置中的真空度可达10~^(-1)Pa,在放置模拟月壤的情况下,真空度可达7 Pa,能够满足模拟月面钻进过程热特性试验的要求。此外,通过测量抽真空过程中真空度随时间的变化情况还得出了模拟月壤出气量曲线,对模拟月壤真空系统的实验应用具有重要价值。

The third stage of China＇ s lunar exploration project presented the task of drilling samples of lunar soil over 2 m deep, which motivates us to study the thermal characteristics during the drilling process. To support this research, a lunar surface vacuum environmental simulation device was designed. According to the requirements of the drilling test, a three-part and dismountable vacuum chamber was designed which was pumped from the bottom of the chamber. Considering the lunar soil simulant＇ s size and rapid vacuum acquire- ment requirements, a cribriform lunar soil container with multi-layer filtrations was designed. Based on the de- mand of repeatable drilling tests in the same condition, the slewing mechanism with missing teeth gear was de- signed which allowed external operation. Finally, a three-stage diffusion pump set was selected according to the vacuum and dust tolerance requirements. Experimental results show that the vacuum of this simulation de- vice reaches to 10-1 Pa without lunar soil inside, and reaches to 7 Pa with lunar soil inside. These performance indicators satisfy the vacuum requirements of the drilling test. The outgassing amount curve of simulated lunar soil is obtained by measuring the variation of vacuum with time during the pumpout process, which is valuable for the lunar soil vacuum system＇ s application.