The “Lunar Laser Ranging Retroreflector for the 21st Century” (LLRRA-21) will improve our knowledge of the lunar interior and the ability to test General Relativity and Gravitation by perhaps two orders of magnitude. Recently the focus of the research on the LLRRA-21 has been on the thermal analysis and the ability to manufacture the large solid CCR. Current thermal analysis is focused on the behavior of the Apollo retroreflector arrays. Their signal level goes from 10%, during the night, to 1%, during full moon, of the expected value. Of particular value is the data taken on the return signal level during a lunar eclipse. The thermal simulation of the Apollo retroreflectors during an eclipse will be presented. This is particularly important for the development of the LLRRA-21 since we must develop a design that is not subject to the same degradation seen in the Apollo arrays. The other recent work addresses the challenges in the manufacture of the 100 mm solid cube corner reflector. This has focused upon the recent measurements of the homogeneity of the material and the ability to make accurate measurements of the offset angles and the inhomogeneity of the material.