Miniature three-mirror telescope for the thermal infrared

The current paper describes the optical and mechanical design of a compact Three-Mirror Anastigmate (TMA) telescope which is installed at the ISS as an earth observation demonstrator for the thermal-infrared spectral range. The TMA bases on a Korsch type design. It has a focal length of 150 mm and an aperture of F/3 and allows for a diffraction limited performance at the design wavelength of 10 μm. The ground resolution reaches 80 m from the ISS. The mechanical design fits into a design space of 80x80x150 mm3 which would correspond to 1.5 U of a typical CubeSat for the telescope or 3U for the whole instrument, respectively.