NASA's Advanced Cryocooler Technology Development Program (ACTDP)

Over the years, NASA has developed a wide variety of new cryocooler technologies, as they represent a significant enabling capability for both Earth and space-science missions. Recent achievements include 50-80 K Stirling, pulse tube, and Brayton flight cryocoolers, and multistage development-model coolers at temperatures down to 10K. The largest technology push within NASA right now is in the temperature range of 4 to 6K. Missions such as the James Web Space Telescope, Terrestrial Planet Finder, and future generations of space telescopes, plan to use infrared detectors operating between 4 and 6K. Similarly, future x-ray and microwave missions plan to use microcalorimeters and bolometers operating at milli-Kelvin temperatures and will require 4-6 K cooling to precool their sub-Kelvin refrigerators. To address cryocooler development for these next-generation missions, NASA initiated the Advanced Cryocooler Technology Development Program (ACTDP) in 2001. Since that time, the program has completed detailed designs and development-model hardware of three hybrid pulse tube and Stirling cryocooler concepts for cooling to 4-18 K. This paper presents an overview of the ACTDP program including programmatic objectives and timelines, and summarizes the excellent progress of the three design concepts being fabricated and tested at this time.