A Comparative Study of Maksutov-Cassegrain and Ritchey-Chretien Optical Designs for 6U CubeSats

We present a comparative study on the optical designs of Maksutov-Cassegrain and Ritchey-Chretien imagers for 6U Earth observation CubeSats. Maksutov-Cassegrain optical design is based on all- spherical optical components whereas, the Ritchey-Chretien type optical design is containing aspherical optical components. Both optical designs are optimized using identical system constraints for performance, size, and weight. Two optical designs are optimized for a diffraction-limited optical performance over +/- 1.50 full field of view. While each design has an 88 mm aperture, the RC design is f/5.7 and the Maksutov-Cassegrain design is f/7.4. The MTF criteria limit is set to be greater than 0.2 at Nyquist frequency (91 lp/mm) for the two designs. The optical performance analysis and, tolerance analysis of both optical designs are compared, and the advantages and disadvantages of both designs are discussed for the 6U CubeSat platform.