Cryocooler Applications

Space cryocoolers are miniature refrigerators designed to cool sensitive spacecraft components to cryogenic temperatures. Cryogenic temperatures are necessary for the operation of many modern devices such as infrared detectors and focal planes, solid-state gamma-ray detectors, and a number of emerging superconducting technologies. Typical temperatures range from the boiling point of liquid Nitrogen at 77 K (-321°F), down to near the boiling point of liquid Helium at 4 K (-453°F). Many near-term and future space-instrument programs within NASA and the DoD depend upon the successful application of long-life, low-vibration space cryocoolers.

JPL Cryocooler Program Focus

In the 1988 timeframe increasing numbers of proposed space-instrument programs within NASA and the Ballistic Missile Defense Organization (BMDO) were in need of high-reliability, long-life, low-vibration space cryocoolers. To ensure the success of its emerging cryogenic instrument commitments, the Jet Propulsion Laboratory (JPL) implemented a focused multi-year cryocooler program. Over the past 10+ years the JPL cryocooler program has included the procurement/development of pulse tube cryocoolers for the Atmospheric Infrared Sounder (AIRS) and Tropospheric Emission Spectrometer (TES) instruments, the conduct of extensive characterization testing of 22 industry-developed cryocoolers, the development and flight-testing of a wide variety of cryocooler integration technologies, and the development of sorption cryocoolers for use at 10 to 25 K. Good reviews of the overall JPL and NASA cryocooler programs are presented in the review papers titled "JPL Cryocooler Development and Test Program: A 10-year Overview" and "Overview of NASA Space Cryocooler Programs."

The high level of commonality that exists between JPL/NASA and DoD cryocooler requirements has fostered a highly collaborative, cooperative program at JPL involving a combination of NASA and DoD sponsorship, and a close working relationship with the world-wide cryocooler development community. Links to the various JPL cryocooler activities are available through the above photo buttons and the entries on the left NavBar.

JPL Cryocooler Program Structure

The JPL cryocooler program has been focused in four areas:

1. The fundamental focus of the JPL cryocooler program is supporting the development and cryogenic engineering of JPL instruments that require cryocoolers to meet their scientific objectives. This activity involves cryogenic instrument design, cryocooler definition, selection and procurement, cryocooler integration engineering, and extensive cryogenic system testing. Several JPL flight instruments involving cryocoolers are currently being supported. The largest are JPL's Atmospheric Infrared Sounder (AIRS) instrument and the Tropospheric Emission Spectrometer (TES) instrument.
2. To support the design of JPL's cryogenic instruments, a second principal focus has involved extensive characterization testing of industry-developed cryocoolers. This activity has been conducted to provide a thorough performance database for use by JPL and the broader NASA and DoD instrument development and cryocooler development communities. JPL initiated its cryocooler characterization program in support of the AIRS instrument in 1989, and greatly expanded the effort under the sponsorship of the Ballistic Missile Defense Organization (BMDO) and the Air Force Research Laboratory (AFRL) in 1992. Over the past several years 22 different cryocooler models have been characterized.
3. The third element of JPL's cryocooler program involves conducting research to develop cryocooler integration technologies needed to enhance the successful incorporation of cryocoolers into space instruments. Example cooler integration technologies include heat switches, heat interceptors, and closed-loop vibration suppression systems. A valuable part of this activity has been the conduct of selective flight experiments to provide flight heritage data and insure that no unresolved issues exist with respect to meeting the complete end-to-end development cycle of flight hardware.
4. The fourth element of JPL's cryocooler program involves conducting research and development of advanced vibration-free sorption refrigerators for operation in the range of 10 to 25 K. An important accomplishment in this area has been the successful development of JPL's Brilliant Eyes Ten-Kelvin Sorption Cryocooler Experiment (BETSCE), which was successfully operated aboard STS 66 in 1996. Present sorption cryocooler research is in support of the Planck mission.