For small satellite remote sensing missions, a large aperture telescope more than 400mm is required to realize less than
1m GSD observations. However, it is difficult or expensive to realize the large aperture telescope using a monolithic
primary mirror with high surface accuracy. A segmented mirror telescope should be studied especially for small satellite
missions. Generally, not only high accuracy of optical surface but also high accuracy of optical alignment is required for
large aperture telescopes. For segmented mirror telescopes, the alignment is more difficult and more important. For
conventional systems, the optical alignment is adjusted before launch to achieve desired imaging performance. However,
it is difficult to adjust the alignment for large sized optics in high accuracy. Furthermore, thermal environment in orbit
and vibration in a launch vehicle cause the misalignments of the optics. We are developing an adaptive optics system
using a MEMS deformable mirror for an earth observing remote sensing sensor. An image based adaptive optics system
compensates the misalignments and wavefront aberrations of optical elements using the deformable mirror by feedback
of observed images. We propose the control algorithm of the deformable mirror for a segmented mirror telescope by
using of observed image. The numerical simulation results and experimental results show that misalignment and
wavefront aberration of the segmented mirror telescope are corrected and image quality is improved.
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