Measurement of optical characteristics of solar panels used on satellite

An automatic measurement device is developed to measure Spectral Bidirectional Reflectance Distribution Function (BRDF) of various samples in the band from 400 to 2000 nm. Spectral BRDF of two kinds of solar panels (silicon solar panel and gallium arsenide solar panel) used on satellite is measured. Spectral Directional Hemisphere Reflectance (DHR) of the solar panels is measured in the band from 400 to 1800 nm. Measured data of the two kinds of solar panel exhibit a high specular reflection nature and a total hemisphere reflectance lower than 0.1 in the band from 400 to 1000 nm. Specular peaks of gallium arsenide solar panel are higher and narrower than those of silicon solar panel in the measured data of spectral BRDF. DHR of silicon solar panel increases to approximately 0.6 quickly at wavelength greater than 1000 nm. As to gallium arsenide solar panel, DHR remains below 0.3 in the band from 1000 to 1800 nm.