With the INFN experiment “ETRUSCO (Extra Terrestrial Ranging to Unified Satellite COnstellations)” we used the “Satellite/lunar laser ranging Characterization Facility” (SCF) [3] located at INFN-LNF in Frascati, Italy, to characterise and model the detailed thermal behavior and the optical performance (“SCF-Test”) of LAGEOS1 and of a prototype hollow cube corner retroreflector. Our key experimental innovation is the concurrent measurement and modeling of the optical far field diffraction pattern (FFDP) and the temperature distribution of the retroreflector payload under thermal conditions produced with a close-match solar simulator. These unique capabilities provide experimental validation of the space segment for Satellite and lunar laser ranging (SLR/LLR). Uncoated retroreflector with properly insulated mounting can minimize thermal degradation and significantly increase the optical performance, and as such, are emerging as the recommended design for modern GNSS2 satellites. We report some results of an extensive, first-ever SCF-Test program performed on a LAGEOS engineering model retroreflector array provided by NASA (the “LAGEOS Sector”), which showed a good performance. The LAGEOS sector measurements demonstrated the effectiveness of the SCF-Test as an SLR/LLR diagnostic, optimization and validation tool in use by NASA, ESA and ASI. We also report the first-ever SCF-Test of a prototype hollow retroreflector provided by NASA, which showed an acceptable performance in the limited tested temperature range. These unprecedented results are the starting point for the development and validation of compact and (potentially) lightweight arrays of hollow laser retroreflectors with the size and the optical specifications to be selectively chosen depending on the specific space mission (that is satellite velocity aberration).