Dell'Agnello, Simone - Next-Generation Laser Retroreflectors for Solar System Exploration, Geodesy and Gravitational Physics

Abstract: 
We are developing next-generation laser retroreflectors for solar system exploration, geodesy and for the precision test of General Relativity (GR) and new gravitational physics: a micro-reflector array (INRRI, Instrument for landing-Roving laser Retroreflectors Investigations), a midsize reflector array, CORA, a large single, large retroreflector (MoonLIGHT, Moon Laser Instrumentation for General relativity High accuracy Tests). They will be fully characterized at the SCF_Lab (Satellite/lunar/gnss laser ranging and altimetry Characterization Facilities Laboratory), a unique and dedicated lab infrastructure of INFN-LNF, Frascati, Italy (www.lnf.infn.it/esperimenti/etrusco/). Research program:
1. Laser retroreflector devices to determine landing accuracy, rover positioning during exploration and planetary/moons surface georeferencing. These devices will be passive, wavelength-independent, long-lived reference point enabling the performance of full-column measurement of trace species in the Mars atmosphere by future space-borne lidars. These measurements will be complementary to highly-localized measurements made by gas sampling techniques on the Rover or by laser back-scattering lidar techniques on future orbiters and/or from the surface. INRRI will also support future science experiments of quantum physics laser communications exploiting the polarization states of laser photons, carried out among future Mars Orbiters and Mars Rovers. This will be possible also because the INRRI laser retroreflectors will be metal back-coated and, therefore, will not change the photon polarization. The instrument is also being proposed for landings on the Moon (two Google Lunar X Prize Missions, namely Moon Express and Astrobotic). The added value of INRRI is its low mass, compact size, zero maintenance and its usefulness for any future laser altimetry, ranging, communications, atmospheric lidar capable Mars orbiter, for virtually decades after the end of the Mars surface mission, like the Apollo and Lunokhod lunar laser retroreflectors.
2. Tests of GR with LLR on MoonLIGHT reflector (see abstract of D. Currie)
3. Extension of program to:
• Mars, Phobos and Deimos
• Jupiter and Saturn icy/rocky moons
• Near Earth Asteroids
4. Development of new gravitational physics models and set experimental constraints using also laser ranging and laser reflectors in the solar system:
• Extension of General Relativity to include Spacetime Torsion
• Non-Minimally Coupled (NMC) Gravity, non minimal coupling between matter and curvature (so-called f1+f2 theories)
5. Strong synergism with:
• Ground stations of International Laser Ranging Service (Apache Point Lunar Laser-ranging Operation, in the US; MLRO, Matera Laser Ranging Observatory in Italy)
• Data Laser-Comm.; mining of moons and asteroids
• Search for exolife on Jupiter/Saturn moons.