Thermal design and analysis of 70 K octagonal passive radiant cooler

Over the years, advancement in meteorological payloads has led to the increase in detector spectral range from short wave infrared to long wave infrared bands. As the detector spectral range coverage increases, they require lower detector temperatures, which makes heat rejection increasingly difficult. Enhancing the cooler performance requires reducing the cooler internal parasitic as well as the external environmental heat loads while constraining the passive cooler field of view to space. Efforts have been made to achieve lower temperature with improved design and considerable reduction in mass of the cooler. This paper presents the thermal design and analysis of a three stage octagonal passive radiant cooler used to attain a temperature less than 70 K with 18 mW detector dissipation which is the typical heat load for line detectors in geo-imaging missions.