Test and thermo-optical analysis for qualification of LARES Satellite cube Corner reflectors

In this document will be shown and explained all the experiences and the activities executed during the Ph.D. studies, from November 2009 up to November 2011. The whole work has been developed in La Sapienza - Universita di Roma", in a special facility for simulated space environment settled up in 2010. To re fine some part of this work a stage in GFZ - GeoForschungsZentrum " has been attended, thanks to the collaboration of Dr. Reinhart Neubert. The aim of this work was been to qualify the CCRs of the LARES satellite. The last developments of the project LARES have led to some results that have called for these kind of tests: thermal simulations have shown an operative temperature of the satellite in orbit in a range from 80C up to 150C, higher than the values expected. According to these last results, to ensure the good working of CCRs and of their mounting systems, a procedure of painting of the surface of the satellites has been proposed. Anyway, even if these proposal would assure the drop in temperature, there were some risks about the fragmentation and detachment of the paint during in-orbit phases, after some years of exposition to the space environment. Because LARES satellite aims to measure Lense-Thirring with a very high precision these e ects could introduce some errors. So the proposal of validation of the CCRs in simulated space environment in the range calculated by the simulation has been performed to ensure the good working of the optics of LARES satellite, avoiding the painting procedure in case of successful results. All the tests realized on CCRs have shown a good working capacity of the systems even at high temperature, with just some negligible e ffects of energy loss because of mechanical deformations caused by the severe thermal condition imposed to the system