In current CubeSat observation satellites, the main design constraint is the available space. Standards dictating the unit dimensions of the payload severely restrict the maximum aperture and focal length of the optical instrument. In this paper, the authors present the results of work to produce a novel DeploScope optical system for a CubeSat-type observation satellite with a segmented aperture of the primary mirror deployed in space. The telescope is designed for Earth observation and is expected to find its application in the military, precision agriculture or environmental disaster prevention. The work includes a detailed analysis of the segment aperture effect on image repeatability for different numbers of main mirror segments. Based on it, the optimal configuration of the optical model of the telescope with an aperture of 188.5 mm and a focal length of 1100 mm was selected. Based on this analysis, a so-called laboratory version of the telescope was built, providing the possibility of free correction of each segment of the primary mirror while maintaining a solid stable base for other components of the module. Imaging tests were carried out on the laboratory version of the instrument and the system was optimized for a version suitable for implementation in the payload structure of the microsatellite.