Published by European Journal of Control, doi: 10.1016/j.ejcon.2015.03.003, 2015 1 Satellite‐to‐satellite attitude control of a long‐distance spacecraft formation for the Next Generation Gravity Mission Enrico Canuto (1), Luigi Colangelo (1), Mauricio Lotufo (1), Sabrina Dionisio (2) (1) Politecnico di Torino, Dipartimento di Automatica e Informatica Corso Duca degli Abruzzi 24, 10129 Torino, Italy enrico.canuto@polito.it, luigi.colangelo@polito.it, mauricio.lotufo@polito.it (2) Thales Alenia Space Italia Strada Antica di Collegno 253, 10135 Torino, Italy sabrina.dionisio@thalesaleniaspace.com Contact author Enrico Canuto tel. +39 011 090 7026 fax +39 011 090 7099 ABSTRACT The paper presents the design and some simulated results of the attitude control of a satellite formation under study by the European Space Agency for the Next Generation Gravity Mission. The formation consists of two spacecraft which fly more than 200 km apart at an altitude from the Earth’s ground of between 300 and 400 km. The attitude control must keep the optical axes of the two spacecraft aligned with a microradian accuracy (pointing control). This is made possible by specific optical sensors accompanying the inter-satellite laser interferometer, which is the main payload of the mission. These sensors allow each spacecraft to actuate autonomous alignment after a suitable acquisition procedure. Pointing control is constrained by the angular drag-free control, which is imposed by mission science (Earth gravimetry at a low Earth orbit), and must zero the angular acceleration vector below 0.01 microradian/s 2 in the science frequency band. This is made possible by ultrafine accelerometers from the GOCE-class, whose measurements must be coordinated with attitude sensors to