Application of cryogenic thermal switch technology to dual focal plane concept for Brilliant Eyes sensor payload

Through the use of cryogenic thermal switch technology, the Brilliant Eyes (BE) government baseline payload configuration for the Flight Demonstration System (FDS) has been enhanced to provide infrared sensing capability with and without a running cryogenic refrigerator. This paper presents a summary of the baseline cooling configurations, assesses the advantages and disadvantages of the candidate thermal switch designs, and describes the requirements and configuration for a validation demonstration utilizing a sorption bed gas source. The primary infrared focal plane array (IRFPA) is cooled by a pair of cryogenic refrigerators at 60 K and a co-located second infrared focal plane assembly operating at a higher temperature is passively cooled by a cryogenic radiator at 135 K. The configuration relies on a cryogenic switch to thermally isolate the two cooling systems. The cryogenic thermal switch also has application to the Objective Flight System to reduce heat load parasitics from a redundant refrigerator system. Several thermal switch designs (including a gas gap switch, with remote storage or sealed gas, and a diode heat pipe) were evaluated. A configuration and requirements were developed for a validation demonstration program utilizing a gas gap sorption switch. The requirements were also flowed into an existing cryogenic flexible diode heat pipe technology program.