Extremely large optical infrared space telescope with multiple diffractive optical elements

We introduce a concept study of an extremely large optical infrared space telescope. The main science mission is (1) to spatially resolve nearby exoplanets with habitable surface environment and (2) to map gaseous disk around the first stars in the early Universe. We require a spatial resolution of at least 1 micro arc-second to distinguish the ocean, land, plants, and volcano on the exoplanets at 10 persec from us. Therefore we require a telescope aperture size of at least 100 km. A combination of magnetically controlled formation flights of pico satellites and multiple diffractive optical elements, will enable us to realize such extremely large-aperture space telescope.