2844 20160701171711.0 10.1051/eas/1045032 DOI ASTROimport-1001 Katz, D. 2011 Gaia spectroscopy: processing, performances and scientific returns During the five years of the mission, the Gaia spectrograph, the Radial Velocity Spectrometer (RVS) will repeatedly survey the celestial sphere down to magnitude V ~ 17-18. This talk presents: (i) the system which is currently developed within the Gaia Data Processing and Analysis Consortium (DPAC) to reduce and calibrate the spectra and to derive the radial and rotational velocities, (ii) the RVS expected performances and (iii) scientific returns. Cropper, M. Meynadier, F. Jean-Antoine, A. Allende Prieto, C. Baker, S. Benson, K. Berthier, J. Bigot, L. Blomme, R. Boudreault, S. Chemin, L. Crifo, F. Damerdji, Y. David, M. David, P. Delle Luche, C. Dolding, C. Frémat, Y. Gerbier, N. Gerssen, J. Gómez, A. Gosset, E. Guerrier, A. Guy, L. Hall, D. Hestroffer, D. Huckle, H. Jasniewicz, G. Ludwig, H.-G. Martayan, C. Morel, T. Nguyen, A.-T. Ocvirk, P. Parr, C. Royer, F. Sartoretti, P. Seabroke, G. Simon, E. Smith, M. Soubiran, C. Steinmetz, M. Thévenin, F. Turon, C. Udry, S. Veltz, L. Viala, Y. EAS Publications Series 45 2011 189-194 http://esoads.eso.org/abs/2011EAS....45..189K published in NONREF