Future advanced heterodyne sensors for submillimeter-wave receivers require 50 to 100 mW of cooling at 15 to 20 K for the sensor, and 1 to 2 W cooling at 80 to 120 K for the local oscillator, with size and input power suitable for use in a Small Sat. A 3-stage pulse tube cryocooler is well-suited for this type of application, offering a simple, reliable option with TRL 5 heritage in a larger cryocooler size, and allowing a design optimized to the sensors cooling and temperature requirements. CU Aerospace (CUA) will use innovative materials and low cost cold head design and assembly, coupled with Lockheed Martins (LM) industry-leading multi-stage pulse tube expertise, to provide NASA with a compact, affordable cryocooler for submillimeter detectors. Our team proposes to: 1) Perform a thorough thermodynamic trade study of 2-stage and 3-stage cold head configurations optimized to provide simultaneously 50-100 mW cooling at 15-20 K and 1-2 W cooling at 80-120 K, to achieve high efficiency, low mass, and compact packaging. Different regenerator materials and heat exchanger configurations will be included in the trade study. 2) Additively manufacture using Direct Metal Laser Sintering an optimized finned heat exchanger and demonstrate its capability to survive thermal cycling when press-fit into a cold head flange. 3) Generate a solid model of the cold head during Phase I so that it is ready for procurement, assembly, and testing in Phase II. 4) Continue the process of qualifying CUA to provide flight cold head subassemblies for future LM Space programs as a way to reduce cost and schedule. This work will leverage the MDA SBIR Phase II as well as CU Aerospaces past flight hardware development and delivery on programs such as Propulsion Unit for Cubesats (PUC) delivered to the Air Force. Potential NASA Applications (Limit 1500 characters, approximately 150 words): Three-stage cryocoolers are generally required when cooling to 15-20 K as required by heterodyne sensors. Staged pulse tubes are ideally suited for space applications because adding stages does not add moving parts, such as with Stirling or Brayton coolers, so reliability remains high. NASA heterodyne sensors, as well as other instruments requiring temperatures from 10-30K would benefit from a low-mass, reliable 3-stage pulse tube cryocooler to improve mission capability. Potential Non-NASA Applications (Limit 1500 characters, approximately 150 words): Multiple-stage cryocoolers can benefit all cryogenic space applications by cooling secondary components and intercepting parasitic heat loads at higher temperature, reducing power and mass. Applications including remote sensing satellite constellations, weather satellite constellations, earth science instruments, and deep space astrophysics instruments can all benefit from multiple-stage cooling. Duration: 6
