The Radiative Cooler cools the cold focal plane by radiating heat to cold space. It has a cold stage, an intermediate stage, a radiation shield and a combination earth shield and cooler door. Temperature controlled outgas heaters (controlled to 318° K) are mounted on both the cold and intermediate stages to provide temporary heating of the cold surfaces should on-orbit contamination occur. The cold stage outgas heater also serves as a backup for the cold focal plane heater. The flat rectangular corners of the Radiative Cooler structure that extend beyond the main circular cross section serve as radiation elements to dissipate heat from the Band 5, 6 and 7 preamplifiers which are inside. Table 3.7 shows the cooler characteristics. In this table it can be seen that the Cooler has a large field of view to cold space. This field of view must remain free of any spacecraft structures, the sun, and the Earth.

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Last Updated on April 26, 1999