Caption: 
Southwest Research Institute collaborated with UT San Antonio to analyze lunar soil samples and determine the effects of space weathering on their far-ultraviolet reflectance. SwRI measured the reflectance of the Apollo 11 soil sample in SwRI’s Slater Crater ultra-high vacuum instrument suite. Weathering increases the abundance of nanophase iron inclusions on the grain rims, which is primarily responsible for its darker ultraviolet reflectance. 