A laboratory study of the photometric properties of Mars Global Soil Simulant MGS-1 and its variants. (March 2023)

• Record Type: Journal Article
• Authors: Sun, Yuxue; Jiang, Te; Zhuang, Yan; Zhang, Hao; Britt, Daniel T.; Zhu, Meng-Hua
• Is Part Of: Planetary and space science. Volume 227(2023)
• Publication Date: 2023-03
• Subjects: Martian soil analogs -- Martian surface -- Bi-directional reflectance -- Photometric properties -- Reflectance spectroscopy; Space sciences -- Periodicals; Atmosphere, Upper -- Periodicals; Sciences spatiales -- Périodiques; Haute atmosphère -- Périodiques; 523
• DOI: 10.1016/j.pss.2023.105639
• Languages: English
• ISSNs: 0032-0633

Abstract

Abstract: Laboratory photometric measurements of Martian soil simulants can provide useful information for analyzing in-situ optical measurements on the Martian surface. We measured the hyper-spectral bidirectional reflectance of Mars Global Soil Simulant MGS-1 and its three variants. By performing photometric inversions, we obtained the single scattering albedo, phase function, surface roughness, and the opposition effect parameters at eight discrete wavelengths, 432 ​nm, 450 ​nm, 530 ​nm, 601 ​nm, 750 ​nm, 900 ​nm, 1200 ​nm, and 1700 ​nm. By comparing these results with the in-situ measurements of Martian soils by the Mars Exploration Rovers Spirit and Opportunity and the Mars Science Laboratory Curiosity, we find the MGS-1 has very similar spectral single scattering albedo with the Curiosity soil, and all of its three variants have higher single scattering abledos than the Martian soils. However, the MGS-1S is spectrally similar to one of the sulfur-rich areas on Mars. The retrieved single scattering phase functions of all simulants exhibit stronger forward single scattering features than the average Martian soils measured by MER Spirit and Opportunity. The retrieved surface roughness parameters of the Martian soil simulants are between 17° and 26°, and this large roughness value is inconsistent with the macroscopic flatness of the sample surface, implying that the small-scale roughness plays an important role in the measurement. It was also found that the roughness parameters have clear anti-correlation with the single scattering albedo. In addition, the phase reddening effect was observed in all soil simulants and the maximum value of the color ratio is not sensitive to the incident zenith angle, but the phase angle at which the maximum value of the color ratio is located increases with incident zenith angle. Our results suggest that the similarities and differences of the physical parameters (i.e., the single scattering albedo, phase function, surface roughness, and opposition effect parameters) within the Martian soil simulants should be carefully considered in the interpretation on the hyper-spectral data, in particular the photometric data for the in-situ Martian observations. Highlights: Measured the hyper-spectral bi-directional reflectance of Martian soil simulants MGS-1 and its three variants. Performed photometric inversions using the Hapke model to obtain the single scattering albedo and phase functions. Similar and different optical properties of the simulant and Mars in-situ data have been discussed.