我国探月工程可采用的一种月球钻探取样方法的初步分析

Elementary Analysis on One of the Possible Drilling and Sampling Techniques for China Lunar Exploration Project

美国和前苏联已完成的月球取样方法分别是载人登月取样和地面遥控取样钻机取样。基于美国和前苏联的方法,提出了一种可供我国嫦娥工程选用的月壤钻探取样方案,即用遥控取样钻机,配备硬质合金钻头、空心螺旋钻具,采用振动-回转钻进工艺。在高真空和低重力条件下,可选用空心螺旋钻具来解决排屑和钻压问题。顺利排屑的基本条件为钻具的螺旋升角应小于月壤与钻具之间的摩擦角、钻具的回转速度应大于临界转速。通过分析计算可知在月球上采用外螺旋钻具时,临界转速比在地球上要小得多,因此在获得同样的回转力矩条件下可匹配较小功率的电动机。

Sampling characteristics on the Moon completed by the US and the former Soviet Union are manned and ground-based remote drilling respectively. The paper presents a Lunar soil drilling sampling alternative for China Chang＇e Project, that is, remote-controlled sampling rig, equipped with carbide bit and hollow stem continuous auger, using rotary and impact dirlling process. To resolve the issue of removing cutting and the weight on the bit in high vacuum and low gravity conditions, it is bound to use the hollow stem continuous auger. The basic conditions for removing cutting in time are that the helix angle should be less than the friction angle between the soil and the stem auger, and that the rotation speed should be greater than the critical rotary speed. By analysis and calculation we can see that the critical rotary speed of the stem continuous auger is much smaller on the Moon than on the Earth. It is capable to use a smaller power motors on the Moon than on the Earth to obtain the same rotary torque.