  The capability of the adaptive optics to correct for the segmentation error
is analyzed in terms of the residual wavefront RMS and the power spectral
density of the phase. The analytical model and the end-to-end simulation give
qualitatively equal results justifying the significance of the geometrical
matching between segmentation geometry and the actuators/subaperture
distribution of the adaptive optics. We also show that the design of the
wavefront sensor is rather critical.
