P. Champagne

DEVELOPMENT OF A 4.5 K PULSE TUBE CRYOCOOLER FOR SUPERCONDUCTING ELECTRONICS

Lockheed Martins (LM) Advanced Technology Center (ATC) has developed a four stage pulse tube cryocooler (stirling-type pulse tube system) to provide cooling at 4.5 K for superconducting digital electronics communications programs. These programs utilize superconducting niobium integrated circuits [1, 2]. A prior ATC 4 stage unit has provided cooling to 3.8 K. [3] The relatively high cooling loads for the present program led us to a new design which improves the 4.5 K power efficiency over prior systems. This design includes a unique pulse tube approach using both He-3 and He-4 working gas in two compression spaces. The compressor utilizes our standard moving magnet linear motor, clearance seal and flexure bearing system. The system is compact, lightweight and reliable and utilizes our aerospace cooler technology to provide unlimited lifetime. The unit is a proof of concept, but the construction is at an engineering model level. Follow on activities for improvements of performance and more compact packagi...

Development of a Space‐Type 4‐Stage Pulse Tube Cryocooler for Very Low Temperature

The Lockheed Martin Advanced Technology Center (LMATC) has built and tested a 4‐stage pulse tube cryocooler, which provides simultaneous cooling at 6 K and 18 K. The cryocooler is designed to meet NASA’s cryocooler needs for low temperature, with immediate application to the Terrestrial Planet Finder, Constellation‐X, and other future space‐science missions. The simplicity with LMATC’s approach of the single compressor, coldhead, and electronic controller makes it very appealing for applications requiring high reliability. It further allows the system to be readily modified for different program requirements. The LM pulse tube is a simple 4‐stage coldhead with no moving parts, driven by a long‐life linear flexure‐bearing clearance‐seal compressor. The cryocooler is designed to provide 20 mW of cooling at 6 K and 150 mW cooling at 18 K while rejecting heat at 290 K. Performance data is presented, showing excellent cryocooler performance, meeting JPL’s cooling requirements, and achieving a no‐load temperatu...

Miniature Pulse Tube Cryocooler for Space Applications

Lockheed Martin’s Advanced Technology Center (LM ATC) has developed a miniature, lightweight pulse tube cryocooler system for space operation under funding from NASA/GSFC. The cold end is a U-tube configuration, and is driven by a dual opposed piston flexure bearing compressor. The compressor utilizes a moving magnet linear motor and incorporates a number of features that simplify assembly and enhance reliability. This cooler is designed for 0.3 W of cooling at 65 K with a 310 K rejection temperature, 15 W of compressor power, and a mass of less than 1.25 kg. Three engineering model cryocoolers are to be delivered to NASA/GSFC. Two have been completed and test data is presented here on the EM performance.

Development of Pulse Tube Cryocoolers for HTS Satellite Communications

The Advanced Technology Center of Lockheed Martin is developing high-capacity (10 W @ 77 K) and low-capacity (0.5 W @ 77 K) pulse tube cryocoolers as part of a program to develop reduced weight satellite communications payloads utilizing high-temperature superconducting (HTS) microwave circuits. A consortium of Com Dev, DuPont, and Lockheed Martin is working together with NASA Lewis Research Center to develop this technology under a DARPA program.

Performance of a Two-Stage Pulse Tube Cryocooler for Space Applications

Lockheed Martin has developed a two-stage pulse tube cryocooler under contract to the Air Force Phillips Laboratory. The cooler is an intermediate bypass design in an in-line configuration. At a reject temperature of 295 K, the cooler simultaneously produced 0.6 W at 56 K and 0.32 W at 35 K. With no heat load on either stage, the cold stage reached 23 K and the intermediate stage reached 48 K. This cooler was driven by a 10.9 cm 3 swept volume flexure bearing compressor, developed by Lockheed Martin for low-cost cryocooler applications. We also observed evidence of dc mass flow through the intermediate capillary and speculate that this resulted in some loss in second-stage cooling power. We observed unstable behavior of the second-stage temperature which we also attribute to dc flow.

Lockheed Martin RAMOS Engineering Model Cryocooler

Lockheed Martin’s Advanced Technology Center (LM-ATC) is developing the cryocooler system for the United States infrared instrument on the Russian-American Observational Satellites (RAMOS) under contract to the Space Dynamics Laboratory. The project is presently fabricating the engineering model, which consists of the cryocooler and electronic controller.

Very high capacity aerospace cryocooler

Long-term cryogenic propellant storage requires mechanical cryocoolers to maintainzero or very low cryogen boil-off rates. Very large cryogen tanks such as those proposedfor orbital fuel depots may require cryocoolers with very high cooling capacity. In-situresource generation and storage of oxygen and methane on Mars also requires highcapacity cryocoolers, and low mass is extremely desirable for planetary missions becauseof the cost associated with landing mass on the surface of another planet. LockheedMartins Advanced Technology Center has developed a high capacity low mass aerospacecryocooler with very high power density. This 7 kg pulse tube cryocooler can provide20 W of cooling at 70 K while rejecting heat at 300 K. This large cooling capability couldalso be used to cool large optical structures or other devices with high heat loads. Testingof the cooler with a secondary heat exchanger attached to the pulse tube was alsoconducted, and results are discussed.

HIGH PERFORMANCE PULSE TUBE CRYOCOOLERS

Lockheed Martins Advanced Technology Center has been developing pulse tube cryocoolers for more than ten years. Recent innovations include successful testing of four-stage coldheads, no-load temperature below 4 K, and the recent development of a high-efficiency compressor.This paper discusses the predicted performance of single and multiple stage pulse tube coldheads driven by our new 6 kg “M5Midi” compressor, which is capable of 90% efficiency with 200 W input power, and a maximum input power of 1000 W. This compressor retains the simplicity of earlier LM-ATC compressors: it has a moving magnet and an external electrical coil, minimizing organics in the working gas and requiring no electrical penetrations through the pressure wall. Motor losses were minimized during design, resulting in a simple, easily-manufactured compressor with state-of-the-art motor efficiency.The predicted cryocooler performance is presented as simple formulae, allowing an engineer to include the impact of a highly-optimized cryoc...

Lockheed Martin Two-Stage Pulse Tube Cryocooler for GIFTS

Lockheed Martin’s Advanced Technology Center (LM-ATC) is developing the cryocooler system for the Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS). This is a NASA New Millennium Program (NMP) Earth Observing-3 mission to demonstrate revolutionary science enabling technologies. One of the new technologies for future generation remote sensors is the two-stage pulse tube cryocooler.

Lockheed Martin 6K/18K Cryocooler

Under contract with the Jet Propulsion Laboratory (Advanced Cryocooler Technology Development Program), Lockheed Martin’s Advanced Technology Center (LM-ATC) is developing a four-stage pulse tube cryocooler and electronic controller to provide simultaneous cooling at 6 K and 18 K. LM-ATC successfully completed the design phase of the program, where a robust, simple pulse tube cryocooler system was designed to meet JPL’s cryocooler needs. The simplicity of LM-ATC s approach, with a single compressor, coldhead and electronic controller, makes it very appealing for the large observatories (Constellation-X, Terrestrial Planet Finder, and the James Webb Space Telescope) that require high reliability.