Design of a Compact Telephoto Objective for 6U CubeSats

We present the optical design of a compact telephoto objective that can be accommodated on 6U-sized CubeSats for Earth observation. The design consists of spherical lenses made of space-compatible materials and operates in the visible region. The objective has F/5.5 diffraction-limited performance over the 2.58-degree full field of view and is optimized for panchromatic imaging in the visible spectrum. The tolerance analysis of the optical design is performed to generate error budgets related to optical manufacturing and alignment. The results show that a design achieves the targeted MTF budget.