Abstract

Wide field-of-view imaging optics offers a huge potential for space-based Earth observation and climate change monitoring by capturing global data. We present the design and proof-of-concept demonstration of a freeform 2-mirror space-based telescope featuring a full field-of-view of 120°, nearly reaching Earth observation from limb to limb from a nominal altitude of 700 km, while showing a spatial resolution of 2.6 km, and fitting within 1 CubeSat unit. Our design benefits from freeform optics to maximize the field-of-view, while maintaining a diffraction-limited image quality and minimizing the system dimensions. Particularly, both mirror surfaces were accurately modelled and optimized using an XY polynomial description. Subsequently, the mirrors are manufactured using high-precision 5-axis milling and ultraprecision diamond tooling, after which a laboratory demonstrator setup of the telescope was realized. We believe this design paves the way towards future space missions enabling an improved Earth observation, leading to an enhanced monitoring of climate and climate change.

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