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Under contract with the Air Force Research Lab (AFRL), Lockheed Martin has built and tested a 3-stage pulse tube cryocooler which provides cooling at 10K and 75K. The cooler was designed for 200mW cooling at 10K and 8W cooling at 75K. The pulse tube is a simple 3-stage coldhead with no moving parts, driven by a long-life linear flexure-bearing clearance-seal compressor. The coldhead is a robust U-tube arrangement, with all metal seals for long life. Performance data will be presented. Future Air Force and Department of Defense (DoD) satellites will require efficient, low temperature cryocoolers to support space surveillance, missile defense, and other mission applications. The use of Very Long Wave Infrared (VLWIR) focal planes using arsenic doped silicon detectors operating at 10K which can detect to 25 micron wavelength has long been sought as the solution to the mid course missile defense mission. The immaturity of 10K cryocooler technology has impeded the use of VLWIR focal planes in current space payloads. A viable, efficient 10K cryocooler could provide further benefits through the use of on-focal plane readout and signal processing using low temperature superconducting electronics. The resultant smaller apertures produce cheaper, lighter sensors, much easier to host in a space-based system. An efficient, compact 10K cryocooler would provide significant capability improvements to future DoD systems. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Launched on NASA’s Aura spacecraft on July 15, 2004, JPL’s Tropospheric Emission Spectrometer (TES) instrument has completed a successful first year in space and captured a number of important lessons. The instrument contains four focal plane arrays in two separate housings cooled to 65 K by a pair of NGST pulse tube cryocoolers. The instrument includes a two-stage passive cooler to cool the optical bench to 180 K. The cryocooler system design is tightly coupled with the overall thermal control design to maximize performance. Soon after cooling the optical bench and focal planes to their operating temperatures on August 20, 2004, ice contamination of the focal planes led to the need of a decontamination cycle. Ice buildup of cryogenic surfaces led to increased cryocooler heat loads. After six months of successful science operations, plans were developed to increase the optics temperature to 187 K to improve the interferometer optical alignment and obtain higher quality science data. The plan is in place and will be implemented in the near future. This paper provides a general overview of the cryogenic system design and reviews the instrument cryogenic performance over the past year. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

A Large heat lift 40 to 80 K Pulse Tube Cooler (LPTC) is currently under development in partnership between AL/DTA, CEA/SBT and THALES Cryogenics. The Engineering Model (EM) foreseen is aiming to provide 2 W of cooling capacity at 50 K for 10°C rejection temperature and for 125 watts input power to the compressor’s motors. Cold finger development models (DM) have been manufactured with an in-line architecture and connected to an off-the-shelf compressor from Thales Cryogenics. In parallel, the compressor motor has been optimized and prototyped. The various trade-offs, performed both on the cold finger and compressor side, during the development phase are presented. This work is funded by the European Space Agency (ESA/ESTEC Contract N°18433/04/NL/AR) in the frame of future Earth Observation instruments development. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Under contract with the Space Dynamics Laboratory, Lockheed Martin’s Advanced Technology Center (LM-ATC) has built and tested the two-stage Engineering Model of a space flight pulse tube cryocooler, which provides simultaneous cooling at 75 K and 130 K. The cryocooler is robust and simple, consisting of a two-stage coldhead with no moving parts, driven by a linear flexure-bearing compressor and powered by a high-efficiency electronic controller that includes ripple suppression and vibration cancellation. A distance of up to one meter separates the coldhead and compressor. The cryocooler was designed to simultaneously provide 0.75 W of cooling at 75 K and 6 W cooling at 130 K while conductively rejecting heat at 313 K. Total system power is 125 W. Performance data is presented, showing excellent cryocooler performance. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

Lockheed Martin’s Advanced Technology Center has developed a compact coaxial pulse tube cryocooler for avionics applications. The cooler was designed to deliver in excess of 1W cooling at 77K with a heat rejection temperature of 70°C, and to cool down from ambient temperature in a very short period of time. The cryocooler utilizes our MINI compressor, developed for NASA-GSFC, coupled with a newly-designed coaxial pulse tube designed to approximate the Standard Advanced Dewar Assembly (SADA II) packaging envelope. The cryocooler mass is 1.25 kg. Test data show excellent performance, with cooldown times of less than 6 minutes (coldhead only, with no additional thermal mass attached to the coldhead). Performance data will be shown for a variety of operating conditions. A discussion of low cost pulse tube cryocoolers will also be presented. This cryocooler was developed and tested with Lockheed Martin IRAD funding. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]