Sorption cooler system. The system is fully redundant. One of the compressor assemblies, mounted on one of the warm radiator panels, which faces cold space, is highlighted in orange. Heat pipes run horizontally connecting the radiators on three sides of the service vehicle octagon. The second compressor assembly is the black box on the right. A tube-in-tube heat exchanger carries high pressure hydrogen gas from the compressor assembly to the focal plane assembly and low pressure hydrogen back to the compressor, with heat-exchanging attachments to each of the three V-grooves. Colours indicate temperature, from warm (red, orange, purple) to cold (blue).