Two Simulated Spectral Databases of Lunar Regolith: Method, Validation, and Application

Our simulated lunar regolith spectra database, based on the Hapke AMSA radiative transfer model (RTM), is a large supplement to the limited number of lunar spectra data. By analyzing the multiple solutions and applicable scopes of the Hapke model by means of Newton interpolation and the least square optimization method, an improved method was found for the simulation of spectra, but it remained challenging to use to invert mineral abundance. Then, we simulated the spectra, mineral abundance, particle size and maturity of 57 mare and highland samples of the Lunar Soil Characterization Consortium (LSCC) in size groups of 10 µm, 10–20 µm and 20–45 µm. The simulated and measured spectra fit well with each other, with correlation coefficients greater than 0.99 and root mean square errors at a magnitude of 10-3. The parameters of mineral abundance, particle size and maturity are highly consistent with the measured values. Having confirmed the reliability of our simulation method, we analyzed the mechanism, reliability and applicability of the “spectral characteristic angle parameter” proposed by Lucey using the simulated spectral data of lunar regolith. Lucey’s method is only suitable for macro analysis of the entire moon, and the error is large when it is used for areas with high abundance of forsterite or ilmenite. In the spectral simulation of lunar regolith, olivine was subdivided into forsterite and fayalite, and the two end-members were mixed to approximately estimate the effect of the chemical composition of olivine on the spectra, which has been confirmed to be feasible.

Effect of Vacuum Environment on Micro Morphology and Porosity of Lunar Soil Concrete

Lunar soil concrete with sulfur system was prepared. The XRD, XRF and SEM datas of lunar soil concrete under atmospheric pressure and vacuum environment after 28 days of curing were compared. The changes of composition and microstructure during solidification of sulfur lunar soil under vacuum and atmospheric pressure were studied. The changes of porosity under atmospheric pressure and vacuum environment were analyzed and compared. Semi quantitative analysis and evaluation are carried out to compare different experimental phenomena.The results show that the vacuum environment has little effect on the element composition of lunar soil concrete. Sulfur exists in the form of single substance in lunar soil concrete, which has the effect of cementation and bonding. The porosity of lunar soil concrete becomes larger under vacuum environment. It can provide technical reserves for the follow-up utilization of in-situ lunar resources and the construction of lunar scientific research stations.

Extraterrestrial Photosynthesis by Chang’E-5 Lunar Soil

In light of significant effort conducted to manned deep space exploration, it is of high technological importance and scientific interest to develop the lunar life supporting system for long-term exploration and exploitation. And lunar in situ resource utilization offers great opportunity to provide the material basis of life supporting for lunar habitation and traveling. Based on the analysis of the structure and composition, the Chang’E-5 lunar soil sample was used for lunar-surface solar energy conversion, i.e. the extraterrestrial photosynthesis catalysts. By evaluating the performance of the Chang’E-5 lunar sample as photovoltaic-driven electrocatalyst, photocatalyst and photothermal catalysts, the full water splitting and CO2 conversion are able to be achieved with solar energy, water and lunar soil, with a wide range of product distribution, including O2, H2, CO, CH4 and CH3OH. Thus, we propose a potentially available extraterrestrial photosynthesis pathway on the moon, which could help us to achieve a ‘zero-energy consumption’ environment and life support system on the moon.