The goal of GGonGround is to reach a sensitivity to differential accelerations of the test masses only $10$ times larger than required in space for GG to improve current tests of the Universality Free Fall and the Equivalence Principle by $4$ orders of magnitude. The frequency of interest is the signal frequency in space $\nu_{orb}=1.7\cdot10^{-4}$~Hz, upconverted  to $1$~Hz by  rotation of the whole GG satellite in space  (no motor, no bearings) and to $0.2\div3$~Hz by rotation of the test cylinders on ground (requires motor and bearings).


 \cite{IntegrationTime}
 
 
 Measure patch effects and demonstrate that they are not relevant; Phase Sensitive Detection @ $24\,\rm h$ in preparation for GG in space data analysis
 
Demonstrate on bench laser gauge noise to $r_{laserRO}\simeq10^{-12}\,\rm{pm/\sqrt{Hz}}\ @ \ 1\div2\,\rm{Hz}$ 


Manufacture suspensions required for GG, meassure elastic constants and quality factors and confirm requirements of GG



P.K. Chapman and A.J. Hanson “An Eotvos Experiment in Earth Orbit,” Proc. Conf. on Expt’al Tests of Grav. Theories, p. 228. Ed. R.W. Davies, J.P.L. Pub., Pasadena, CA (1971).

Touboul, B. Foulon, L. Lafargue and Gilles Metris, “The microscope mission," Acta Astronautica 50 (2002) 433-443

Worden, Jr., P.W., 1976, PhD thesis (Stanford University).


Worden, Jr., P.W. & Everitt, C.W.F., 1973, Proceedings Int. School
 of Physics E. Fermi, Course LVI: Experimental Gravitation
 (Academic Press, New York), p. 381.
 
 Nobili, A.M., Bramanti, D., Comandi, G.L., Toncelli, R., Polacco, E., Catastini, G.: Radiometer  effect in space missions to test the equivalence principle. Phys Rev, D. Rapid Commun. 63,
101101(R) (2001)


J. Astronaut. Sc., 43, 219-242 (1995)


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\bibitem{GGExpAstr2009} {A. M. Nobili} {\it et al.}, Exp. Astr. 23, 689-710 (2009)\\[-25pt]