Determination of the thermophysical characterisitics of the Moon soil with depthed thermoprobes

Abstract

Determination of thermophysical characteristics of the lunar soil is an important scientific task. This article examined three options for penetrating thermal probe design for measuring the thermal properties of soil. A numerical simulation was carried out, and revealed distortion of temperature distribution, which can be caused by design of the thermal probe and affect the measurements, was studied,. The first scheme is a rod thermal probe, which is similar to the thermal probe used in Apollo missions. The second scheme is an improved rod thermal probe, with a detachable heater with an autonomous power source at the lower end of the rod. The third scheme is a more complicated design made by a series of autonomous heaters and temperature sensors that are fixed in a pre-drilled well and have no thermal connection. According to the calculation results, the rod thermal probe used in the Apollo missions and the thermal probe with a detachable heater showed the same level of temperature distribution distortion. The influence of the design of the split thermal probe was by 30% lower. The last type of the probe may allow to improve the accuracy of measurements of the TPC of the lunar soil.