Cooling large space telescopes to 4 kelvin

摘要

To obtain sky background limited viewing in the mid and far infrared, cooling the telescope itself is required. In the past the lowest temperatures have been achieved using stored cryogen systems. Due to weight constraints and the desire for long life observatories, stored cryogen coolers will be replaced by passive coolers, mechanical coolers and solid state coolers. Some of the challenges and opportunities presented by these large cold telescopes and cryogenic cooling systems are described with emphasis on telescopes that require temperatures below 6 K.