Spaceborne tele-objective design for earth imaging

This thesis presents an electro-optic camera design to fit into a 6U CubeSat platform for Earth observation from the low Earth orbit (LEO). The design is aimed to achieve a 4.5 m ground sampling distance (GSD) at 400 km altitude. The optical design of the camera is based on a refractive, telephoto objective architecture consisting of six spherical lenses whose optical materials are compatible with the space environment. An F/5.5 telephoto objective, near diffraction-limited performance over 2.6-degree of the full field of view (FFOV) is optimized utilizing a ray-tracing software (i.e., OpticStudio) for panchromatic imaging between the spectrum of 450 – 700 nm. A commercial, complementary metal-oxide semiconductor (CMOS) 2-D imaging sensor is selected to provide a better than 15 km swath width. A tolerance analysis of the optical design has been carried out to identify limitations related to the alignment and optical manufacturing. The modulation transfer function (MTF) and signal-to-noise ratio (SNR) budgeting analysis are also performed to show the performance of the electro-optic camera design.