The Exoplanet Characterisation Observatory (EChO) is a proposed space telescope that has been selected for further studies as part of the Cosmic Vision roadmap of the European Space Agency, and is competing with four other missions for the M3 slot in the programme. The mission is currently under assessment, and a decision by the Science Programme Committee is expected by February 2014.
EChO will be the first dedicated mission to investigate exoplanetary atmospheres, addressing the suitability of those planets for life and placing our Solar System in context. EChO will provide high resolution, multi-wavelength spectroscopic observations. It will measure the atmospheric composition, temperature and albedo of a representative sample of known exoplanets, constrain models of their internal structure and improve our understanding of how planets form and evolve. It will orbit around the L2 Lagrange point, 1.5 million km from Earth in the anti-sunward direction.
^Tinetti, G.; Cho, J. Y. K.; Griffith, C. A.; Grasset, O.; Grenfell, L.; Guillot, T.; Koskinen, T. T.; Moses, J. I.; Pinfield, D.; Tennyson, J.; Tessenyi, M.; Wordsworth, R.; Aylward, A.; Van Boekel, R.; Coradini, A.; Encrenaz, T.; Snellen, I.; Zapatero-Osorio, M. R.; Bouwman, J.; Du Foresto, V. C.; Lopez-Morales, M.; Mueller-Wodarg, I.; Pallé, E.; Selsis, F.; Sozzetti, A.; Beaulieu, J. P.; Henning, T.; Meyer, M.; Micela, G.; Ribas, I. (2011). "The science of EChO". Proceedings of the International Astronomical Union6: 359. Bibcode:2011IAUS..276..359T. doi:10.1017/S1743921311020448.edit