A high level of diversity has already been observed among the planets of ourown Solar System. As such, one expects extrasolar planets to present a widerange of distinctive features, therefore the characterisation of Earth- andsuper Earth-like planets is becoming of key importance in scientific research.The SEARCH (Spectropolarimetric Exoplanet AtmospheRe CHaracerisation) missionproposal of this paper represents one possible approach to realising theseobjectives. The mission goals of SEARCH include the detailed characterisationof a wide variety of exoplanets, ranging from terrestrial planets to gasgiants. More specifically, SEARCH will determine atmospheric properties such ascloud coverage, surface pressure and atmospheric composition, and may also becapable of identifying basic surface features. To resolve a planet with a semimajor axis of down to 1.4AU and 30pc distant SEARCH will have a mirror systemconsisting of two segments, with elliptical rim, cut out of a parabolic mirror.This will yield an effective diameter of 9 meters along one axis. A phase maskcoronagraph along with an integral spectrograph will be used to overcome thecontrast ratio of star to planet light. Such a mission would provide invaluabledata on the diversity present in extrasolar planetary systems and much morecould be learned from the similarities and differences compared to our ownSolar System. This would allow our theories of planetary formation, atmosphericaccretion and evolution to be tested, and our understanding of regions such asthe outer limit of the Habitable Zone to be further improved.
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