Curtis R J, Warren T J, Bowles N E
Atmospheric, Oceanic and Planetary Physics, Department of Physics, University of Oxford, Oxford OX1 4BH, United Kingdom.
Rev Sci Instrum. 2021 Mar 1;92(3):034504. doi: 10.1063/5.0038632.
Understanding how the surfaces of airless planetary bodies-such as the Moon-scatter visible light enables constraints to be placed on their surface properties and top boundary layer inputs to be set within thermal models. Remote sensing instruments-such as Diviner onboard the Lunar Reconnaissance Orbiter-measure thermal emission and visible light scattering functions across visible (∼0.38-0.7 µm) to thermal infrared (TIR) wavelengths (∼0.7-350 μm). To provide ground support measurements for such instruments, the Oxford Space Environment Goniometer (OSEG) was built. Initially, the OSEG focused on measuring TIR directional emissivity functions for regolith and regolith simulant samples in a simulated space environment, but it has recently been modified to measure visible wavelength Bidirectional Reflectance Distribution Functions (BRDFs) of samples in ambient conditions. Laboratory-measured BRDFs can be used (1) to test and to help interpret models-such as the Hapke photometric model-and (2) as visible scattering function inputs for thermal models. This paper describes the modifications to and initial calibration measurements taken by the Visible Oxford Space Environment Goniometer with a 532 nm laser, and details how this setup can be used to measure BRDFs of regolith and regolith simulant samples of airless planetary bodies.
了解诸如月球等无大气行星体的表面如何散射可见光，有助于限制其表面特性，并在热模型中设置顶部边界层输入。诸如月球勘测轨道器上搭载的Diviner等遥感仪器，可测量从可见光（约0.38 - 0.7微米）到热红外（TIR）波长（约0.7 - 350微米）范围内的热发射和可见光散射函数。为了给此类仪器提供地面支持测量，牛津空间环境测角仪（OSEG）被制造出来。最初，OSEG专注于在模拟空间环境中测量风化层和风化层模拟样品的热红外方向发射率函数，但最近它已被改装，用于在环境条件下测量样品的可见波长双向反射分布函数（BRDF）。实验室测量的BRDF可用于：（1）测试和帮助解释模型，如Hapke光度模型；（2）作为热模型的可见光散射函数输入。本文描述了配备532纳米激光的可见牛津空间环境测角仪的改装情况及初始校准测量，并详细说明了该装置如何用于测量无大气行星体的风化层和风化层模拟样品的BRDF。
