Ball Aerospace Next Generation 2-Stage 35 K SB235 Coolers

This paper describes the design, development, testing, and performance of the Ball Aerospace SB235 and SB235E long life, 2-stage space cryocoolers optimized for dual temperature simultaneous cooling at 35 K and above. The SB235 and its model derivative SB235E are 2-stage coolers designed to provide simultaneous cooling at 35 K (typically, for HgCdTe detectors) and 100 K (typically, for the optics) and were baselined for the Raytheon SBIRS Low Track Sensor. A qualification unit SB235 was developed and has accumulated 2500 hours in a life test at the Air Force Research Laboratory (AFRL). The SB235 and its higher capacity derivative SB235E were designed for high cooling capacity, power and mass efficiency, and producibility for multiple unit build applications.