月球表面物质介电常数:嫦娥五号月球样品的新启示  

Overview of the dielectric permittivity of lunar surface materials and implications for Chang’E-5 sample measurements

作　　者：法文哲[1] FA WenZhe(Institute of Remote Sensing and Geographical Information System,School of Earth and Space Sciences,Peking University,Beijing 100871,China)

机构地区：[1]北京大学地球与空间科学学院遥感与地理信息系统研究所,北京100871

出　　处：《中国科学：物理学、力学、天文学》2023年第3期2-26,共25页Scientia Sinica Physica,Mechanica & Astronomica

基　　金：国家重点基础研究发展计划(编号:2019YFE0123300);国家自然科学基金(编号:12173004,41941002)资助项目。

摘　　要：月表物质的介电常数决定了电磁波在月球次表层的穿透深度,对月球雷达、微波辐射计、月表电磁实验等科学载荷的设计与数据解译至关重要,有助于定量反演次表层结构与物理性质.对月球物质介电常数的了解,目前主要基于主被动微波遥感数据反演和对Apollo,Luna月球样品的实验测量.2020年12月,我国嫦娥五号探测器从月球正面风暴洋北部成功采集并返回1.731 kg月球样品,为研究月壤介电常数提供了新的样品.本文首先介绍了物质介电常数基础、介质电极化机制、介电常数混合模型和测量方法,接着对月球表面物质介电常数的研究历史与现状进行了系统性梳理与总结,并给出了整个月球表面月壤介电常数的分布图.最后,介绍了我国嫦娥五号着陆区地质背景与月壤特性的最新研究结果,对嫦娥五号月球样品介电常数实验测量给出了建议,并对其潜在科学产出进行了评估.本文对月壤介电常数的梳理与认识,可以为我国后续探月工程中微波遥感载荷设计、雷达数据解译、采样点选取和样品分析等提供理论指导与支撑.The dielectric permittivity of lunar surface materials determines the penetration depth of electromagnetic waves in the lunar subsurface;hence,it is crucial to the design of scientific payloads such as radars,microwave radiometers,and lunar surface electromagnetic experiments.Additionally,dielectric permittivity is a key parameter in deciphering radar and microwave radiometer observations,which is important to obtain quantitative information regarding the subsurface structure and physical properties of the Moon.Our current knowledge of the dielectric permittivity of lunar surface materials depends mainly on the inversion of microwave remote sensing data and laboratory measurements of the Apollo and Luna samples.In December 2020,China’s Chang’E-5 mission successfully collected 1.731 kg of lunar samples from the northern Oceanus Procellarum,thus providing new samples for studying the dielectric properties of lunar materials.In this paper,I will first introduce the basic knowledge of dielectric permittivity,including the dielectric polarization mechanism,dielectric permittivity mixing model,and measurement methods.Then,I will summarize the history and present status of the research on the dielectric permittivity of lunar materials and demonstrate the dielectric permittivity of the Moon.Finally,I will present the latest research results of the geological background and regolith properties of the Chang’E-5 landing region and provide some suggestions regarding the laboratory measurements and potential scientific outcome of the Chang’E-5 lunar samples.The summarization of our current knowledge of the dielectric permittivity of lunar regolith in this paper can provide theoretical guidance and engineering support for microwave sensor design,radar data interpretation,sampling site selection,and sample analysis for China’s future lunar exploration missions.

关 键 词：月壤 介电常数 嫦娥五号 

分 类 号：P184[天文地球—天文学]