Design and Construction of a Laser-Ranged Test Mass for the Deep Space Gravity Probe Mission and Test of a Hollow Retroreflector for the GPS-3

The "Satellite/lunar laser ranging Characterization Facility" (SCF) of INFN-LNF in Frascati, Italy, is devoted to the characterization of the detailed thermal properties and the optical performance of laser- ranged payloads (the "SCF-test") for GNSS, Space Geodesy and Fundamental Physics applications 12. The Optical Lab is a second LNF facility dedicated to the far field diffraction pattern (FFDP) industrial acceptance test of laser cube corner retroreflectors (CCR) for space applications. We tested about 200 flight CCRs to be deployed in space by imminent launches at the two LNF facilities. These launches are for the current American Global Navigation Satellite System Constellation, the GPS-2 by NASA and for the European VEGA Program, by ESA/ASI. Some of the tested CCRs are for undisclosed missions by other space agencies. Deep Space Gravity Probe (DSGP) is a mission led by NASA-JPL (S. Turyshev is the PI), proposed to NASA and to the ESA "Cosmic Vision" program to study the anomalous deceleration of the Pioneer 10 and 11 probes and other important interplanetary science topics. In the context of a three-year study on "Cosmology and Fundamental Physics" (COFIS) funded by ASI and led at national level by P. de Bernardis we designed a prototype laser-ranged test mass for the DSGP satellite formation. This mass is being built at LNF and will be SCF-Tested at the SCF. We are also collaborating with NASA-GSFC (J. McGarry et al) on the test of innovative CCRs for the GPS-3. The goal of this R&D is to convince the US Air Force and Department of Defense of the full functionality of the hollow retroreflector design. This is a prerequisite to propose the deployment of retroreflectors on the GPS-3, which, unlike GALILEO, is a military constellation.