To characterize orbits and atmospheres of exoplanets with large orbits (>= a few AU), direct imaging is nowadays the sole way. From space, this involves high contrast imaging techniques as coronagraphy, differential imaging or wavefront control. Several methods exist or are under development and several small (~1.5m) space telescope missions are proposed. One of them is See-coast (super-Earth explorer coronagraphic off-axis space telescope) which will be proposed to the next ESA Cosmic Vision call. It will provide polarimetric and spectral characterization of giant gazeous planets and possibly Super-Earths in visible light. In this paper, we first detail science cases of this mission. We then describe the foreseen telescope design and its instrumentation. We finally derive performance for a particular instrumental configuration from numerical simulation and we show how See-coast can retrieve planet spectra.