The NASA space telescope  SPHEREx   Thermal and Optical Subsystems. 
SPHEREx spacecraft (photon shields cut away) showing the bus with the payload optical and thermal subsystems. The optics and detector cool passively by radiating heat to space with a 3-stage V-groove passive cooler. Lightweight deployed photon shields protect the cooler and optics from radiation from the Sun and Earth.
NASA
<a rel="nofollow" class="external free" href="http://spherex.caltech.edu/Survey.html">http://spherex.caltech.edu/Survey.html</a>