CRYOCOOLERS 10A publication of the International Cryocooler ConferenceCRYOCOOLERS 10Edited byR. G. Ross, Jr.Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadena, CaliforniaKLUWER ACADEMIC PUBLISHERS NEW YORK, BOSTON, DORDRECHT, LONDON, MOSCOWeBook SBN: 0-306-47090-XPrint SBN: 0-306-46120-X2002 Kluwer Academic PublishersNew York, Boston, Dordrecht, London, MoscowPrint 1999 Kluwer Academic / Plenum PublishersAll rights reservedNo part of this eBook may be reproduced or transmitted in any form or by any means, electronic,mechanical, recording, or otherwise, without written consent from the PublisherCreated in the United States of AmericaVisit Kluwer Online at: http://kluweronline.comand Kluwer's eBookstore at: http://ebooks.kluweronline.comNew YorkPrefaceThe last two years have witnessed a continuation in the breakthrough shift toward pulse tubecryocoolers for long-life, high-reliability cryocooler applications with the development of matureproducts addressed to a wide variety of operating temperatures. On the commercial front, Gifford-McMahon cryocoolers with rare earth regenerators continue to make great progress in openingup the 4 K market. Also in the commercial sector, continued interest is being shown in thedevelopment of long-life, low-cost cryocoolers for the emerging high temperature superconduc-tor electronics market, particularly the cellular telephone base-station market. At higher tem-perature levels, closed-cycle J-T or throttle-cycle refrigerators are taking advantage of mixedrefrigerant gases, spearheaded in the former USSR, to achieve low-cost cryocooler systems in the65 - 80 K temperature range. Tactical Stirling cryocoolers, the mainstay of the defense industry,continue to find application in cost-constrained commercial applications and space missions, butcontinue to shrink in numbers as the defense industry continues its consolidation.To archive the latest developments and performance of this expanding stable of cryocoolers,this book draws upon the work of many of the international experts in the field of cryocoolers. Inparticular, Cryocoolers 10 is based on their contributions at the 10th International CryocoolerConference, held in Monterey, California, in May 1998. The program of this conference con-sisted of 128 papers; of these, 101 are published here. Although this is the tenth meeting of theconference, which has met every two years since 1980, the authors works have only been madeavailable to the public in hardcover book form since 1994. This book is thus the third volume inthis new series of hardcover texts for users and developers of cryocoolers.As a significant addition to this proceedings, Cryocoolers 10 contains ten articles highlight-ing cryocooler developments that have taken place in the former USSR over the past 20 years.Eight of these cover key accomplishments of the Special Research and Development Bureau(SR&DB) in Cryogenic Technology of the Institute for Low Temperature Physics and Engineer-ing of the National Academy of Sciences in the Ukraine; they are listed in the subject indexunder: SR&DB of the Ukraine. Also, two articles authored by staff of the Kharkov State Poly-technic University in the Ukraine are included; they cover more recent research activities onpulse tube type coolers and provide insight into the teaching of cryocooler design in the Ukraine.The ten Ukrainian articles reflect a significant increase in collaboration between the cryocoolerresearch centers in the former USSR and the broader worldwide cryocooler community.Because this book is designed to be an archival reference for users of cryocoolers as much asfor developers of cryocoolers, extra effort has been made to provide a thorough Subject Indexthat covers the referenced cryocoolers by type and manufacturers name, as well as by the scien-tific or engineering subject matter. Extensive referencing of test and measurement data, andapplication and integration experience, is included under specific index entries. Contributingorganizations are also listed in the Subject Index to assist in finding the work of a known institu-tion, laboratory, or manufacturer. To aide those attempting to locate a particular contributorswork, a separate Author Index is provided, listing all authors and coauthors.Prior to 1994, proceedings of the International Cryocooler Conference were published asinformal reports by the particular government organization sponsoring the conference typi-cally a different organization for each conference. A listing of previous conference proceedingsvvi PREFACEis presented in the Proceedings Index, at the rear of this book. Most of the previous proceedingswere printed in limited quantity and are out of print at this time.The content of Cryocoolers 10 is organized into 15 chapters, starting first with an introduc-tory chapter providing cooler overviews and summaries of major government cryocooler devel-opment programs. The next few chapters address cryocooler technologies organized by type ofcooler, starting with Stirling cryocoolers, pulse tube cryocoolers, and associated research. Next,Brayton, Joule-Thomson, hybrid J-Ts, and sorption cryocoolers are covered in a progression oflowering temperatures. Gifford-McMahon cryocoolers and low-temperature regenerators in the4 to 10 K range are covered next, followed by a glimpse into the future with miniature solid-staterefrigerators and advanced refrigeration cycles. The last three chapters deal with cryocoolerintegration technologies and experience to date in a number of representative applications. Thearticles in these last three chapters contain a wealth of information for the potential user ofcryocoolers, as well as for the developer.It is hoped that this book will serve as a valuable source of reference to all those faced withthe challenges of taking advantage of the enabling physics of cryogenics temperatures. Theexpanding availability of low-cost, reliable cryocoolers is making major advances in a number offields.Ronald G. Ross, Jr.Jet Propulsion LaboratoryCalifornia Institute of TechnologyAcknowledgmentsThe International Cryocooler Conference Board wishes to thank Lockheed Martin AdvancedTechnology Center, which hosted the 10th ICC, and to express its deepest appreciation to theConference Organizing Committee, whose members dedicated many hours to organizing andmanaging the conduct of the Conference. Members of the Organizing Committee and Board forthe 10th ICC include:CONFERENCE CO-CHAIRSTed Nast, Lockheed Martin ATCpeter Kittel, NASA/ARCCONFERENCE ADMINISTRATORAurie Pedronan, Lockheed Martin ATCPROGRAM CHAIRMANPeter Kerney, conductusCONFERENCE SECRETARYJill Bruning, Nichols Research Corp.PUBLICATIONSRon Ross, Jet Propulsion LabTREASURERRay Radebaugh, NISTPROGRAM COMMITTEEJohn Brisson, MITWilliam Burt, TRWDavid Glaister, Aerospace Corp.Geoffrey Green, NSWCTom Kawecki, NRLLawrence Wade, JPLADVISORY BOARDStephen castles, NASA/GSFCChris Jewell, ESARalph Longsworth, APD CryogenicsYoichi Matsubara, Nihon Univ., JapanMartin Nisenoff, NRLMarko Stoyanof, AFRLWalter Swift, Creare Inc.Klaus Timmerhaus, U. of ColoradoJia Hua Xiao, NISTIn addition to the Committee and Board, key staff personnel made invaluable contributions tothe preparations and conduct of the conference. Special recognition is due C. Stoyanof, C.Seeley, J. M. Lee, C. Nast, and C. Kerney.viiContentsGovernment Cryocooler Development and Test Programs 1An Overview of the Performance and Maturity of Long Life Cryocoolers forSpace Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D. Glaister, The Aerospace Corp., Albuquerque, NM; M. Donabedian and D. Curran, TheAerospace Corp., El Segundo, CA; and T. Davis, AFRL, Kirtland AFB, NMAir Force Research Laboratory Cryocooler Technology Development. . . . . . . .T.M. Davis, J. Reilly, and Lt. B.J. Tomlinson, AFRL, Kirtland AFB, NMEndurance Evaluation of Long-Life Space Cryocoolers at AFRL an Update . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Lt. B.J. Tomlinson, AFRL, Kirtland AFB, NM; and A. Gilbert and J. Bruning, NRC,Albuquerque, NMDARPA Low Cost Cryocooler Performance Testing: Preliminary Results . . . .T.G. Kawecki, NRL, Washington, DC; and S.C. James, AlliedSignal Tech. Services Corp.,Camp Springs, MDDevelopment of Cryogenic Cooling Systems at the SR&DB in the Ukraine ..S.I. Bondarenko and V.F. Getmanets, SR&DB, Kharkov, Ukraine121334355Stirling Cryocooler Developments 59Qualification Test Results for a Dual-Temperature Stirling Cryocooler ......W.J. Gully, H. Carrington and W. Kiehl, Ball Aerospace & Tech. Corp., Boulder, CO; andT. Davis and B.J. Tomlinson, AFRL, Kirtland AFB, NMProgress towards the Development of a 10K Closed Cycle Coolerfor Space Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A.H. Orlowska and T.W. Bradshaw, RAL, Didcot, UK; S. Scull, MMS, Bristol, UK; andLt. B.J. Tomlinson, AFRL, Kirtland AFB, NMDevelopment of a Light Weight Linear Drive Cryocooler forCryogenically Cooled Solid State Laser Systems . . . . . . . . . . . . . . . . . . . . . . . . .L.B.Penswick, STC, Kennewick, WA; and B.P. Hoden, Decade Optical Systems, Inc.,Albuquerque, NMLow-Weight and Long-Life 65K Cooler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .V.T. Arkhipov, V.N. Lubchenko, and L.V. Povstyany, SR&DB. Kharkov, Ukraine; andH. Stears, Orbita Ltd., Kensington, MD59677787i xx CONTENTSThermal Performance of the Texas Instruments 1-W Linear DriveCryocooler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D.L. Johnson, JPL, Pasadena, CAQualification of the BEI B512 Cooler, Part 1 Environmental Tests........D.T. Kuo, A.S. Loc, and S.W.K. Yuan, BEI Tech., Sylmar, CAUse of Variable Reluctance Linear Motor for a Low CostStirling Cycle Cryocooler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .M. Hanes, D. Chase, and A. OBaid, STI, Santa Barbara, CA95105111Pulse Tube Cryocooler Developments 119AIRS PFM Pulse Tube Cooler System-Level Performance . . . . . . . . . . . . . . . . . . . . .R.G. Ross, Jr., D.L. Johnson, and S.A. Collins, JPL, Pasadena, CA; and K. Greenand H. Wickman, LMIRIS, Lexington, MAMultispectral Thermal Imager (MTI) Space Cryocooler Development,Integration, and Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Lt. B.J. Tomlinson, AFRL, Kirtland AFB, NM; W. Burt, TRW, Redondo Beach, CA; D.Davidson and C. Lanes, Sandia Natl Lab, Albuquerque, NM; and A. Gilbert, NRC,Albuquerque, NMIMAS Pulse Tube Cooler Development and Testing . . . . . . . . . . . . . . . . . . . . . . .C.K. Chan, T. Nguyen, R. Colbert, and J. Raab, TRW, Redondo Beach, CA; andR.G. Ross, Jr. and D.L. Johnson, JPL, Pasadena, CADevelopment of a 1 to 5 W at 80 K Stirling Pulse Tube Cryocooler . . . . . . . . .Y. Hiratsuka and Y.M. Kang, Daikin Indus., Tsukuba, Japan; and Y. Matsubara,Nihon Univ., Funabashi, JapanDevelopment of a 2 W at 60 K Pulse Tube Cryocooler forSpaceborne Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .V. Kotsubo, J.R. Olson, and T.C. Nast, Lockheed Martin ATC, Palo Alto, CAPerformance of a Two-Stage Pulse Tube Cryocooler forSpace Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .J.R. Olson, V. Kotsubo, P.J. Champagne, and T.C. Nast, Lockheed Martin ATC,Palo Alto, CADevelopment of Pulse Tube Cryocoolers for HTS SatelliteCommunications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .V. Kotsubo, J.R. Olson, P. Champagne, B. Williams, B. Clappier, and T.C. Nast,Lockheed Martin ATC, Palo Alto, CAA Pulse Tube Cryocooler for Telecommunications Applications ................J.L. Martin and C.M. Martin, Mesoscopic Devices, Golden, CO; and J. Corey, CFIC,Troy, NYDesign and Preliminary Testing of BEIs CryoPulse 1000,the Commercial One Watt Pulse Tube Cooler . . . . . . . . . . . . . . . . . . . . . . . . . . . .S. W.K. Yuan, D. T. Kuo, and A.S. Loc, BEI Technologies, Slymar, CA119129139149157163171181191CONTENTS xiPulse Tube Cryocooler Configuration Investigations 197Optimal Design of a Compact Coaxial Miniature Pulse Tube Cooler . . . . . . . .Y.L. Ju, Y. Zhou, J.T. Liang, and W.X. Zhu, Cryogenics Lab., Chinese Acad. of Sci.,Beijing, ChinaPerformances of Two Types of Miniature Multi-Bypass Coaxial Pulse TubeRefrigerators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .J.T. Liang, J.H. Yang, W.X. Zhu, Y. Zhou, and Y.L. Ju , Cryogenics Lab, Chinese Acad.of Sci., Beijing, ChinaDevelopment of a 5 to 20 W at 80 K GM Pulse Tube Cryocooler . . . . . . . . . . . . .S. Fujimoto and Y.M. Kang, MEC Lab, Daikin Indus., Tsukuba, Japan; and Y. Matsubara,Nihon Univ., Funabashi, JapanConceptual Design of Space Qualified 4 K Pulse Tube Cryocooler . . . . . . . . . .G.R. Chandratilleke, Y. Ohtani, H. Nakagome, and K. Mimura, Toshiba Corp., Kawasaki,Japan; N. Yoshimura and Y. Matsubara, Nihon Univ., Funabashi, Japan; H. Okuda, ISAS,Sagamihara, Japan; and T. Iida and S. Shinohara, NASDA, Tsukuba, JapanPerformance Dependence of 4K Pulse Tube Cryocooler onWorking Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .N. Yoshimura, S.L. Zhou and Y. Matsubara, Nihon Univ., Funabashi, Japan; G.R.Chandratilleke, Y. Ohtani, and H. Nakagome, Toshiba R&D Center, Kawasaki, Japan;H. Okuda, ISAS, Sagamihara, Japan; and S. Shinohara, NASDA, Tsukuba, JapanResearch of Two-Stage Co-Axial Pulse Tube Coolers Driven by a ValvelessCompressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .L.W. Yang, J.T. Liang, Y. Zhou, and J.J. Wang, Cryogenics Lab, Chinese Acad. of Sci.,Beijing, ChinaExperimental Investigation of a Unique Pulse Tube Expander Design . . . . . . .C.S. Kirkconnell, Raytheon Systems Co., El Segundo, CAAn Experimental Study on the Heat Transfer Characteristics of theHeat Exchangers in the Basic Pulse Tube Refrigerator . . . . . . . . . . . . . . . . . .S. Jeong and K. Nam, Korea Adv. Institute of Sci. and Tech., Taejon, KoreaDouble Vortex Tube as Heat Exchanger and Flow Impedance for aPulse Tube Refrigerator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .M.P. Mitchell, Mitchell/Stirling, Berkeley, CA; D. Fabris, Illinois Inst. of Tech., Chicago,IL; and B.J. Tomlinson, AFRL, Kirtland AFB, NMInvestigations on Regenerative Heat Exchangers . . . . . . . . . . . . . . . . . . . . . . . . . .I. Rhlich and H. Quack, Univ. of Dresden, Dresden, GermanyPressure Drop in Pulse Tube Cooler Components . . . . . . . . . . . . . . . . . . . . . . . . .H.E. Chen, J.M. Bennett, S. Yoshida, A. Le, and T.H.K. Frederking, UCLA, LosAngeles, CA197205213221227233239249257265275Pulse Tube Flow and Operational Stability Investigations 281Experimental Results on Inertance and Permanent Flow inPulse Tube Coolers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .L. Duband, I. Charles, A. Ravex, and L. Miquet, CEA/DRFMC, Grenoble, France; andC.I. Jewell, ESA-ESTEC, Noordwijk, The Netherlands281xii CONTENTSExperimental Results of Pulse Tube Cooler with Inertance Tubeas Phase Shifter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .K. V. Ravikumar, Atlas Scientific, NASA ARC, Moffett Field, CA; and Y. Matsubara, NihonUniv., Funabashi, JapanObservation of DC Flows in a Double Inlet Pulse Tube . . . . . . . . . . . . . . . . . . .V. Kotsubo, P. Huang, and T.C. Nast, Lockheed Martin ATC, Palo Alto, CASuppression of Acoustic Streaming in Tapered Pulse Tubes . . . . . . . . . . . . . . . .J.R. Olson, Lockheed Martin ATC, Palo Alto, CA; and G. W. Swift, Los Alamos Nat1 Lab.,Los Alamos, NMPerformance of a Tapered Pulse Tube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .G.W. Swift, M.S. Allen, and J.J. Wollan, Cryenco Inc., Denver, CONumerical Study of Pulse Tube Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Y. Hozumi, Chiyoda Corp., Yokohama, Japan; M. Murakami, Univ. of Tsukuba, Tsukuba,Japan; and T. Iida, NASDA, Tsukuba, JapanVisualization Study of the Local Flow Field in an Orifice andDouble-Inlet Pulse Tube Refrigerator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .M. Shiraishi and A. Nakano, Mech. Engin. Lab, Tsukuba, Japan; and N. Nakamura,K. Takamatsu, and M. Murakami, Univ. of Tsukuba, Tsukuba, JapanStability Study of Coaxial Pulse Tube Cooler Driven byAir Conditioning Compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .L.W. Yang, J.T. Liang, Y. Zhou, P.S. Zhang, W.X. Zhu, and J.H. Cai, Cryogenics Lab,Chinese Acad. of Sci., Beijing, ChinaGas Contamination Effects on Pulse Tube Performance . . . . . . . . . . . . . . . . . . .J.L. Hall and R.G. Ross, Jr., JPL, Pasadena, CA291299307315321329337343Pulse Tube Modeling and Diagnostic Measurements 351Simple Two-Dimensional Corrections for One-DimensionalPulse Tube Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .J.M. Lee and P. Kittel, NASA ARC, Moffett Field, CA; K.D. Timmerhaus, Univ. of Colo-rado, Boulder, CO; and R. Radebaugh, NIST, Boulder, COPulse Tube Development Using Harmonic Simulations . . . . . . . . . . . . . . . . . . .H.W.G. Hooijkaas, Eindhoven Univ. of Tech.; and A.A.J. Benschop, Signaal-USFA,Eindhoven, The NetherlandsAnalysis of a Two Stage Pulse Tube Cooler by Modelingwith Thermoacoustic Theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A. Hofmann, Forschungszentrum Karlsruhe, Karlsruhe, Germany; and S. Wild, Univ. ofKarlsruhe, Karlsruhe, GermanyModeling Pulse Tube Coolers with the MS*2 Stirling Cycle Code . . . . . . . . . .M.P. Mitchell, Mitchell/Stirling, Berkeley CA; and L. Bauwens, Univ. of Calgary, CalgaryCanadaExperimental Verification of a Thermodynamic Model for aPulse Tube Cryocooler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .J. Yuan and J.M. Pfotenhauer, Univ. of Wisconsin, Madison, WI351359369379387CONTENTS xiiiMeasurements of Gas Temperature in a Pulse Tube Using thePlanar Laser Raleigh Scattering Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .K. Nara, Y. Hagiwara, and S. Ito, Adv. Mobile Telecommunication Tech. Inc., Aichi-ken,JapanMathematical Model of a Wave Cooler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .V.N. Kukharenko, Kharkov State Polytechnic Univ., Kharkov, UkrainePulse Tube Modeling as a Means of Teaching the Design ofCryogenic Refrigerators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .V.N. Kukharenko, Kharkov State Polytechnic Univ., Kharkov, Ukraine395405413Brayton Cryocooler Developments 421Design and Test of Low Capacity Reverse Brayton Cryocooler forRefrigeration at 35 K and 60 K . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .J. McCormick, G. Nellis, W. Swift, and H. Sixsmith, Creare Inc., Hanover, NH; andJ. Reilly, AFRL, Kirtland AFB, NMReverse Brayton Cryocooler for NICMOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .G. Nellis, F. Dolan, J. McCormick, W. Swift, and H. Sixsmith, Creare Inc., Hanover, NH;and J. Gibbon and S. Castles, NASA GSFC, Greenbelt, MDDesign and Qualification of Flight Electronics for the HST NICMOSReverse Brayton Cryocooler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C. Konkel and W. Bradley, Orbital Sciences Corp., Greenbelt, MD; and R. Smith, NASAGSFC, Greenbelt, MD421431439J-T and Throttle-Cycle Cryocooler Developments 449Flight Demonstration of the Ball Joule-Thomson Cryocooler . . . . . . . . . . . . . .R. Fernandez and R. Levenduski, Ball Aerospace & Tech., Boulder, CODesign Optimization of the Throttle-Cycle Cooler with MixedRefrigerant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .M. Boiarski, A. Khatri, APD Cryogenics, Allentown, PA; and V. Kovalenko, Moscow PowerEngin. Inst., Moscow, RussiaLong-Life Cryocooler for 84-90 K . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .V.T. Arkhipov, A.V. Borisenko, V.F. Getmanets, R.S. Mikhalchenko and L.V. Povstiany,SR&DB, Kharkov, Ukraine; and H. Stears, Orbita, Ltd., Kensington, MDMixed Gas J-T Cryocooler with Precooling Stage . . . . . . . . . . . . . . . . . . . . . . . .A. Alexeev, Ch. Haberstroh, and H. Quack, Univ. of Dresden, GermanyExperimental Comparison of Mixed-Refrigerant Joule-Thomson Cryocoolerswith Two Types of Counterflow Heat Exchangers . . . . . . . . . . . . . . . . . . . . .E.C. Luo, M.Q. Gong, Y. Zhou, and J.T. Liang, Chinese Acad. of Sci., Beijing, ChinaMulticomponent Gas Mixtures for J-T Cryocoolers . . . . . . . . . . . . . . . . . . . . . . . .V.T. Arkhipov, V.V. Yakuba, M.P. Lobko, and O.V. Yevdokimova, SR&DB, Kharkov, Ukraine;and H. Stears, Orbita Ltd., Kensington, MD449457467475481487xiv CONTENTSAn Experimental Study and Numerical Simulation of Two-Phase Flowof Cryogenic Fluids through Micro-Channel Heat Exchanger . . . . . . . . . . . .W.W. Yuen, UCSB, Santa Barbara, CA; and I.C. Hsu, Lockheed Martin ATC, Palo Alto, CA497Hybrid J-T Cryocooler Systems for Operation at 4-10 K 505Hybrid 10 K Cryocooler for Space Applications . . . . . . . . . . . . . . . . . . . . . . . . . .R. Levenduski, W. Gully, and J. Lester, Ball Aerospace & Tech., Boulder, CODesign and Development of a 4 K Mechanical Cooler . . . . . . . . . . . . . . . . . . . . .S.R. Scull and B.G. Jones, MMS, Bristol, UK; T.W. Bradshaw and A.H. Orlowska, RAL,Chilton, UK; and C.I. Jewell, ESA-ESTEC, Noordwijk, The NetherlandsLife Test and Performance Testing of a 4 K Cooler for SpaceApplications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T.M. Bradshaw, A.H. Orlowska, RAL, Chilton, UK; and C.I. Jewell, ESA-ESTEC,Noordwijk, The NetherlandsLong-Life 5-10 K Space Cryocooler System with Cold Accumulator . . . . . . . . .V.T. Arkhipov, V.F. Getmanets and A.Y. Levin, SR&DB, Kharkov, Ukraine; and H. Stears,Orbita Ltd, Kensington, MD505513521529Sorption Cryocooler Developments 535Periodic 10 K J-T Cryostat for Flight Demonstration . . . . . . . . . . . . . . . . . . . . .R.C. Longsworth, A. Khatri, and D. Hill, APD Cryogenics, Allentown, PACharacterization of Porous Metal Flow Restrictors for Use as theA.R. Levy, UCSB, Santa Barbara, CA; and L.A. Wade, JPL, Pasadena, CAThermodynamic Considerations on a Microminiature Sorption Cooler ........J.F. Burger, H.J. Holland, H.J.M. ter Brake, H. Rogalla, Univ. of Twente, The Netherlands;and L.A. Wade, JPL, Pasadena, CAFast Gas-Gap Heat Switch for a Microcooler . . . . . . . . . . . . . . . . . . . . . . . . . . . .J.F. Burger, H.J. Holland, H. van Egmond, M. Elwenspoek, H.J.M. ter Brake, andH. Rogalla, Univ. of Twente, The Netherlands535545553565GM Refrigerators and Low-Temperature Regenerators 575Development of a High Efficiency 0.5W Class 4 K GM Cryocooler . . . . . . . . . .T. Satoh, R. Li, H. Asami, and Y. Kanazawa, Sumitomo Heavy Ind. R&D Center,Kanagawa, Japan; and A. Onishi, Sumitomo Heavy Ind. PPD, Tokyo, JapanDevelopment of a High Efficiency 4 K GM Refrigerator . . . . . . . . . . . . . . . . .Y. Ohtani, H. Hatakeyama, and H. Nakagome, Toshiba R&D Center, Kawasaki, Japan;and T. Usami, T. Okamura, and S. Kabashima, Tokyo Inst. of Tech., Yokohama, Japan575581J-T Expander in Hydrogen Sorption Cryocoolers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CONTENTS xvAnalysis of a High Efficiency 4 K GM Refrigerator Operating at aLower Pressure Ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T. Usami, T. Okamura and S. Kabashima, Tokyo Inst. of Tech., Yokohama, Japan; andY. Ohtani, H. Hatakeyama, and H. Nakagome, Toshiba Corp., Kawasaki, JapanNumerical Simulation of 4 K GM Refrigerator . . . . . . . . . . . . . . . . . . . . . . . . . .T. Inaguchi, M. Nagao, K. Naka, and H. Yoshimura, Mitsubishi Electric Corp. Adv. Tech.R&D Center, Hyogo, JapanNumerical Fluid Analysis of Pumping Loss . . . . . . . . . . . . . . . . . . . . . . . . . . . . .K. Naka, T. Inaguchi, M. Nagao, and H. Yoshimura, Mitsubishi Electric Corp. Adv. Tech.R&D Center, Hyogo, JapanMultilayer Magnetic Regenerators with an Optimum Structurearound 4.2 K . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .H. Nakane, T. Hashimoto, and Y. Miyata, Kogakuin Univ., Tokyo, Japan; M. Okamuraand H. Nakagome, Toshiba Corp., Kanagawa, JapanAdvances in Neodymium Ribbon Regenerator Materials . . . . . . . . . . . . . . . . . .T. Felmley, Concurrent Tech. Corp., Johnstown, PAGd-Zn Alloys as Active Magnetic Regenerator Materials forMagnetic Refrigeration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .V.K. Pecharsky and K.A. Gschneidner, Jr., Ames Lab, Iowa State Univ., Ames, IAMagnetocaloric Properties of Gd3Al2 ................................................V.K. Pecharsky and K.A. Gschneidner Jr., Ames Laboratory, Iowa State Univ., Ames, IA;and S. Y. Dankov and A.M. Tishin, Moscow State Univ., Moscow, Russia587593603611621629639Advanced Refrigeration Cycles and Developments 647Development of a Dilution Refrigerator for Low-TemperatureMicrogravity Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P.R. Roach, NASA ARC, Moffett Field, CA; and B. Helvensteijn, Sterling Software, RedwoodShores, CAPreliminary Experimental Results Using a Two Stage SuperfluidStirling Refrigerator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A.B. Patel and J.G. Brisson, MIT, Cambridge, MAInvestigation of Microscale Cryocoolers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .J.M. Shire, A. Mujezinovic, and P.E. Phelan, ASU, Tempe, AZ647655663Cryocooler Integration and Test Technologies 671Development of Advanced Cryogenic Integration Solutions . . . . . . . . . . . . . . .D. Bugby and C. Stouffer, Swales Aerospace, Beltsville, MD; T. Davis, Lt. B.J. Tomlinson,and Lt. M. Rich, AFRL, Kirtland AFB, NM; J. Ku and T. Swanson, NASA GSFC, Greenbelt,MD; and D. Glaister, The Aerospace Corp., Albuquerque, NMCold Accumulators as a Way to Increase Lifetime andCryosystem Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .V.T. Arkhipov, V.F. Getmanets, A.Y. Levin, and R.S. Mikhalchenko, SR&BD, Kharkov,Ukraine; and H. Stears, Orbita Ltd, Kensington, MD671689xvi CONTENTSTest Results of a Nitrogen Triple-Point Thermal Storage Unit . . . . . . . . . . . . .B.G. Williams and I.E. Spradley, Lockheed Martin ATC, Palo Alto, CAOptimal Integration of Binary Current Lead and Cryocooler . . . . . . . . . . . . . .H.M. Chang, Hong Ik Univ., Seoul, Korea; and S. W. Van Sciver, Natl High Magnetic FieldLab, Tallahassee, FLCryogenic Systems Integration Model (CSIM) . . . . . . . . . . . . . . . . . . . . . . . . . . .S.D. Miller and M. Donabedian, The Aerospace Corp., El Segundo, CA; and D.S. Glaister,The Aerospace Corp., Albuquerque, NMHeat Rejection Effects on Cryocooler Performance Prediction . . . . . . . . . . . . .Lt. B.J. Tomlinson, AFRL, Kirtland AFB, NM; and A. Gilbert and J. Bruning, NRC,Albuquerque, NMCryocooler Working Medium Influence on Outgassing Rate . . . . . . . . . . . . . . .V.F. Getmanets, SR&DB, Kharkov, Ukraine; and G.G. Zhun', Kharkov State PolytechnicUniv., Kharkov, UkraineAccelerated Cryocooler Life Tests for Cryodeposit Failures . . . . . . . . . . . . . . . .V.F. Getmanets and G. G. Zhun, SR&DB, Kharkov, Ukraine; and H. Stears, Orbita, Ltd,Kensington, MDThermal Resistance across the Interstitial Material Kapton MT atCryogenic Temperatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .L. Zhao and P.E. Phelan, ASU, Tempe, AZ697707717723733743753Space Cryocooler Applications 761Cryocooler Subsystem Integration for the High Resolution DynamicsLimb Sounder (HIRDLS) Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D.J. Berry, D. Gutow, J. Richards, and R. Stack, Ball Aerospace & Tech., Boulder, COEMI Performance of the AIRS Cooler and Electronics . . . . . . . . . . . . . . . . . . . .D.L. Johnson, S.A. Collins, and R.G. Ross, Jr., JPL, Pasadena, CAThe Application and Integration of Mechanical Coolers . . . . . . . . . . . . . . . . . . .R.M. Wilkinson, S.R. Scull, MMS, Bristol, England; A.H. Orlowska and T.W. Bradshaw,RAL, Chilton, England; and C.I. Jewell, ESA-ESTEC, Noordwijk, The NetherlandsCooling System for Space Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .G.L. Ji and Y. Wu, Shanghai Inst. of Tech. Physics, Chinese Acad. of Sci., Shanghai, ChinaDrive and Control System for a Stirling Cryocooler . . . . . . . . . . . . . . . . . . . . . .W. Biao, G. Ji, and Y. Wu, Shanghai Inst. of Tech. Physics, Chinese Acad. of Sci., Shanghai,ChinaTesting of Infrared Detectors Using a Zero Gravity DilutionRefrigerator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .R.S. Bhatia, J.J. Bock, and P.V. Mason, CIT, Pasadena, CA; A. Benot, CNRS, Grenoble,France; and M.J. Griffin, Queen Mary & Westfield College, London, UKDesign of a 90 K Cryogenic Passive Cooler for the IASI Instrument . . . . . . . .D.J. Doornink, Fokker Space, Leiden, The Netherlands761771781787791795805CONTENTS xviiCryocoolers for Human and Robotic Missions to Mars . . . . . . . . . . . . . . . . . . . .P. Kittel and L.J. Salerno, NASA ARC, Moffett Field, CA; and D.W. Plachta, NASA LeRC,Cleveland, OH815Commercial Cryocooler Applications 823Design Considerations for Industrial Cryocoolers . . . . . . . . . . . . . . . . . . . . . . . .C.M. Martin and J.L. Martin, Mesoscopic Devices, LLC, Golden, COSurvey of Cryocoolers for Electronic Applications (C-SEA) . . . . . . . . . . . . . . . .J.L. Bruning and R. Torrison, NRC, Albuquerque, NM; R. Radebaugh, NIST, Boulder, CO;and M. Nisenoff, NRL, Washington, DCConstruction and Tests of a High-Tc SQUID-Based Heart ScannerCooled by Small Stirling Cryocoolers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 837C.J.H.A. Blom, H.J.M. ter Brake, H.J. Holland, A.P. Rijpma, and H. Rogalla, Univ. ofTwente, The NetherlandsCryocooler Applications for High-Temperature SuperconductorMagnetic Bearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .R.C Niemann and J.R. Hull, Argonne Natl Lab, Argonne, ILAdvanced Cryocooler Cooling for MRI Systems . . . . . . . . . . . . . . . . . . . . . . . . . .R.A. Ackermann and K.G. Herd, GE Corp. R&D, Niskayuna, NY; and W.E. Chen, GEMedical Sys., Florence, SC823829847857Indexes 869Proceedings Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Author Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Subject Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .869871873An Overview of the Performanceand Maturity of Long Life Cryocoolersfor Space ApplicationsD. S. GlaisterThe Aerospace CorporationAlbuquerque, NM, USA 87119M. Donabedian, D. G. T. CurranThe Aerospace CorporationEl Segundo, CA, USA 90245T. DavisThe Air Force Research LabKirtland AFB, NM, USA 87119ABSTRACTA survey is made which identifies more than 30 long life coolers for space applicationscovering a wide variety of thermodynamic cycles and configuration types. These coolers rangein capacities from a few milliwatts to over 10 W at temperatures from 10 K to over 120 K andinclude single and multi-stage designs. The primary objectives of this study were to provide ahardware summary and performance comparison for potential space cryocooler users and toserve as an aid to the Air Force in determining future cryocooler development.Funding for these coolers are being provided by the Department of Defense, NASA, andvarious other government agencies in the U.S. and abroad as well as by internal research anddevelopment moneys from a number of companies throughout the world. The study identifiesseveral existing flight qualified coolers and at least 12 programs which are likely to provideflight qualified units for cooling in the range of 10 to 150 K before the turn of the century. Thesurvey presents an overview and status of the maturity of the various cryocoolers andperformance comparisons are made at 35 K, 60 K, and 100 K.Cryocoolers 10, edited by R. G. Ross, Jr.Kluwer Academic/Plenum Publishers, 1999 12GOVERNMENT CRYOCOOLER DEVELOPMENT AND TEST PROGRAMSACRONYMSAATSRAFRLAIRSATSRBAeBETSCEBMDOCCECOBECOOLLARDODEMDEOSESAFDSFIRSTGSFCHIRDLSHSTHTSSEIMASIRFPAISAMSISSCJPLLADSLMMSMIPASMMRBCMMSMOPITTMSXMTINICMOSPSCRALSBIRS-LSCRSSMCSMTSSPIRIT IIISSCSSRBSSTISTSTESTMUUARSUCSBUSUAdvanced Along Track Scanning RadiometerAir Force Research LaboratoryAtmospheric Infrared SounderAlong Track Scanner RadiometerBritish Aerospace Systems, LimitedBrilliant Eyes Ten Kelvin Sorption Cryocooler ExperimentBallistic Missile Defense OrganizationCryocooler Control ElectronicsCosmic Background ExplorerCryogenic On-Orbit Long Life Active RefrigerationDepartment of DefenseEngineering and Manufacturing DevelopmentEarth Observation SystemEuropean Space AgencyFlight Demonstration SystemFar Infrared Space TelescopeGoddard Space Flight CenterHigh Resolution Dynamic Limb SounderHubble Space TelescopeHigh Temperature Superconductivity Space ExperimentIntegrated Multi-spectral Atmosphere SounderInfrared Focal Plane AssemblyImproved Stratospheric and Mesospheric SounderImproved Standard Spacecraft CoolerJet Propulsion LaboratoryLow Altitude Demonstration SystemLockheed Martin Missiles and SpaceMicholson Interferometer for Passive Atmosphere SoundingMulti-Stage Miniature Reverse Brayton CryocoolerMatra Marconi SpaceMeasurement of Pollution in the TropopauseMid-Course Space ExperimentMulti-spectral Thermal ImagerNear Infrared Camera and Multi-Object SpectrometerProtoflight Space CryocoolerRutherford Appleton Laboratories, U. K.Space Based Infrared Surveillance-LowSpace Cryogenic Refrigeration SystemsSpace and Missiles System CenterSpace Missile Tracking SystemSpace Infrared Imaging TelescopeStandard Spacecraft CoolerSingle-Stage Reverse BraytonSmall Satellite Technology InitiativeSpace Transportation SystemTropospheric Emission SpectrometerThermo-Mechanical UnitUpper Atmosphere Research SatelliteUniversity of California at Santa BarbaraUtah State UniversityOVERVIEW OF PERFORMANCE OF SPACE CRYOCOOLERS 3INTRODUCTIONA variety of long life, mechanical cryogenic refrigerators (cryocoolers) for space areavailable or under development to provide cooling of infrared sensors and spectrometers, opticalelements, low noise amplifiers, superconductivity devices and other scientific instruments foratmospheric monitoring and astronomy. The authors of this paper provide technical support tonearly every United States Department of Defense (DoD) spacecraft program eitherimplementing or potentially implementing cryogenic cooling systems, as well as to the Air ForceResearch Laboratory (AFRL) at Kirtland AFB, NM, which is the DoD center for spacecryocooler and cryogenic technology development. As part of that support, the authors areresponsible for assessing the industry as well as routinely presenting overviews and summariesof space cryocoolers. The AFRL requested the preparation of an overview package of the statusand maturity of space cryocoolers. The intent of this package is to help assess the state of the artand provide guidelines for future development of space cryocoolers. The purpose of this paper isto present a brief overview of the cryocooler data package. It is also the intent of the AFRL thatthis cryocooler data package be available to any user or vendor who requests it.Several caveats should be mentioned concerning the scope of this overview package. Inrecent years, the number of cryocoolers available with potential application to space hasincreased significantly. It is the authors intent to include every cryocooler whose primarypurpose is for space application. However, it is likely that some vendors have been missed andthe package is incomplete. In this regard, the authors encourage input from those vendors whowere left off the summary in this paper.SPACE CRYOCOOLER STATUS AND OVERVIEWAs a result of the large number of coolers representing several different thermodynamiccycles as well as several different hybrid combinations, and many different vendors, time orspace does not permit including all of these coolers. Rather, a selected summary of some of themore prominent coolers and programs are provided in an attempt to provide a representativesample of the total population.Tables 1a through 1e have been prepared to provide an overview. The coolers are listedby vendor in alphabetical order showing the model, cooler type, nominal performance, powerinput including electronics either estimated or measured, the current maturity level ( using thelegend at the end of the table), applicable programs, sponsors, milestones or significant scheduledates, environmental and life testing completed or in progress and finally references cited for thesource of the information. In some cases, multiple model designations are used when there is adifference between the vendors and sponsors designation. In the discussion to follow, thevarious coolers are grouped by the nominal operating temperature range for which the cooler isbest suited. In some cases this will require identifying a specific cooler more than once if it isbeing used over a broad range of temperatures. The four specific temperature ranges used tocategorize the coolers are as follows: 1) 4-12 K, 2) 18-45 K, 3) 50-100 K and 4) over 100 K.It should be noted that new applications with varying temperature requirements and heatloads will need revised designs to optimize performance. This is necessary as the listed coolershave been optimized for single design points such as 2 W @ 60 K but are capable of providingcooling capabilities at lower and higher temperatures. Several of these applications demandweight reductions and higher efficiencies for ~100 K optics cooling due to considerations such asstringent gimbal mass limitations which also limit heat rejection capabilities. The very highspecific powers at ~10K temperatures have also restricted the use of coolers in this range.4 GOVERNMENT CRYOCOOLER DEVELOPMENT AND TEST PROGRAMSOVERVIEW OF PERFORMANCE OF SPACE CRYOCOOLERS 56 GOVERNMENT CRYOCOOLER DEVELOPMENT AND TEST PROGRAMSOVERVIEW OF PERFORMANCE OF SPACE CRYOCOOLERS 78 GOVERNMENT CRYOCOOLER DEVELOPMENT AND TEST PROGRAMSOVERVIEW OF PERFORMANCE OF SPACE CRYOCOOLERS 9Notes to Table 1.1. TMU = Thermo-mechanical unitCCE = Cooler control electronics(assumed to be 6.0 kg if nototherwise specified)Maturity legendCD Conceptual designBB BrassboardEDM Engineering development modelQM Qual modelPF Protoflight modelFM Flight modelFP Flight provenCOTS Commercial off the shelf3.4.5.6.7.Environmental tests completeda.b.c.d.e.f.Random vibrationSine vibrationThermal CycleThermal VacuumEMI/EMCShockg. Flight qualificationsTotal power input (including CCE) estimatedto be equal to 10 watts + compressor inputpower/0.85 when not specifically measured.At 300 K unless otherwise noted (usuallymeasured or assumed to be at the coolermounting flange).Derivative of 50-80 KMultistage requirement modified to single-stage requirementTesting hours left blank when unknown orminimalAlso, now that clearance seal concepts with flexure and gas bearings are showing promise forlong life, attention needs to be focused on improving performance by reducing cooler weight andreducing irreversible losses in the cooler. For these reasons, optimization techniques need to beintroduced, such as those of Bejan46, to minimize both temperature and pressure drops in thecooler components such as critical cold end and hot end working fluid heat exchangers as well asregenerators and recuperators. In addition both cooler and payload/spacecraft system designersneed to optimize the cooling capabilities and load requirements by utilizing temperature stagingof cooling loads to improve overall system efficiency.4-12 K Operating RangeTraditionally, cooling in this range has been accomplished with the use of superfluidliquid helium dewars such as IRAS44 and COBE45 at temperatures near 2 K or solid hydrogencryostats such as the SPIRIT-III flown on the MSX Spacecraft for cooling near 10 K. There hasbeen an incentive to develop cryocoolers for operation in this range because of the desire forlonger life with reduced mass and volume relative to dewars. Coolers with capacity forcontinuous cooling in the 50 to 100 milliwatt range are just now emerging. This region ofoperating temperatures is the least mature technology at this point in time.MMS 4K Hybrid J-T/Stirling. This cooler is the culmination of a development activity startedat RAL in the mid-1980s. Under ESA funding, BAe (prior to being acquired by MMS)developed an engineering model of a 4 K cooler which has since been qualified for spaceflightby MMS. The cooler consists of a two-stage Stirling pre-cooler which is integrated with a J-Tcryostat to achieve final collection of liquid helium to provide cooling at near 4 K. The unitproduces 5 to 10 milliwatts of cooling for somewhat over 200 W of input power. The total massis about 50 kg and is a prime candidate for several astronomy missions including the Far InfraredSpace Telescope (FIRST)29.MMS 10 K Multi-Stage Stirling. This program was initiated by AFRL/BMDO in early 1997with the objective to quickly produce a protoflight quality cryocooler with at least 45 mW ofcooling at 10 K. Towards this goal of a fast turn around, the program leverages off of the MMS20 K hardware and uses essentially a double set of the 20 K compressors (for a total of 4).Through regenerator improvements with rare earth materials, the program now has the potentialto achieve up to 75 mWof cooling with a motor power of 2000 W/Wor less. The program is on2.10 GOVERNMENT CRYOCOOLER DEVELOPMENT AND TEST PROGRAMSschedule to complete a flight quality thermo-mechanical unit by April 1999. The intent of thisprogram is not only to produce a 10 K flight cooler for customers who may need a cryocooler inthe next 3 years, but also to serve as a pathfinder for future, more optimized Stirling and PulseTube 10 K programs.JPL BETSCE 10 K Periodic Sorption. The Brilliant Eyes Ten Kelvin Cryocooler Experiment(BETSCE) was developed under funding from USAF/BMDO/AFRL to demonstrate thetechnology of a hydride sorption cryocooler for operation near 10 K and is described in detail byBard15 and Wade16. The flight demonstration unit flown on STS-77 in May of 1996 was aperiodic cooler supplemented with a Stirling cryocooler to provide 70 K pre-cooling. The flightunit provided 100 milliwatts of cooling at 10 K (on a 15 minute per 24 hour duty cycle ) startingfrom 70 K with a power input of about 200 W @ 290 K. This program was completed but thetechnology derived has been exploited further by application to continuous cooling cryocoolersin the 20-25 K region by Wade16 and Bowman17. These applications are described in the nextsection of this report for coolers in the 18-45 K range. A more detailed description of the designand performance of the 10 K JT cryostat of the BETSCE program is presented by Longsworth34.Ball Hybrid J-T/Stirling (Redstone). This program was recently initiated by AFRL with thegoal of pushing the state of the art and developing a very efficient (less than 1000 W/W motorpower), light weight 10 K cryocooler for space applications (including doped Silicon infrareddetectors). The design utilizes an enhanced 35/60 K Stirling unit (with some minor regeneratorimprovements) to provide precooling at 15 to 18 K to a J-T cooler which provides at least 100mW of cooling at 10 K. The J-T compressor uses a rotary vane design with significant heritagefrom terrestrial commercial applications, but which requires development for long lifeapplication with a dry helium working fluid. This hybrid design takes advantage of the Stirlingefficiency in cooling to cryogenic temperatures from ambient and the efficiency of therecuperative J-T cycle in cooling as the temperature approaches absolute zero.18-45 K Operating RangeThere are several coolers designed primarily for operation near the lower end of thistemperature range and several that are best suited for the 35-45 K range but also operate veryefficiently in the 50-80 K range. Engineering model coolers have been available for severalyears in this operating temperature range and flight qualified coolers are becoming available.Qualified control electronics are lagging somewhat behind but are being developed.MMS 20 K Multistage Stirling. The MMS 20K cooler under development is based primarilyon the 2-stage technology achieved at RAL under ESA funding. The program was initiated inearly 1994 to provide 20 K cooling capability for the FIRST instrument. The back-to-backcompressors are derived from the 50-80 K technology combined with a 2-stage displacer andproduces approximately 120 milliwatts at 20 K plus 400 milliwatts at 30 K for a total inputpower of 122 W. An extensive flight qualification program was completed in early 199728.BALL 30 K Multi-Stage Stirling. This cooler was developed by NASA GSFC and was derivedfrom earlier coolers using RAL/Oxford technology. The cooler uses diaphragm spiral flexuresprings with integral back-to back compressors and a split expander with balancer. The expanderhas incorporated a fixed regenerator design allowing for a lightweight displacer/piston andimproved cooling efficiency. The cooler has undergone successful environmental andperformance testing conducted at GSFC and is presently under life test with approximately 7000hours of accumulated operation.BALL 35/60 K Dual Temperature Cooler. This cooler is being developed by AFRL as acandidate for cooling sensor IRFPAs such as SBIRS LOW. It is a three-stage unit with theupper stage used as a shield for the lower stages that provide 0.4 W @ 35 K and 0.6 W at 60 K.The design was derived from the two stage NASA GSFC 30K program that also used the upperstage as a shield with 0.3 W @ 30 K. The cooler provides very efficient cooling with a TMUOVERVIEW OF PERFORMANCE OF SPACE CRYOCOOLERS 11specific power estimated to be 30 W/W at 60 K and 80 W/W at 35 K. The cooler will bedelivered to AFRL for performance and endurance testing.JPL 20 K Continuous Sorption. JPL is currently developing a 20K continuous sorption cooler(LH2) for the Planck Surveyor program sponsored jointly by NASA and ESA (European SpaceAgency). The system utilizes hydride compressors connected to a J-T cryostat assembly toproduce liquid hydrogen operating near 20 K. A passive radiator operating in deep space atabout 60 K allows the system to produce about 1.2 W of cooling at 20 K with around 400 W ofinput power. An EDM is scheduled to be delivered by the year 2000 with two flight unitsscheduled to be delivered to ESA in 2003. This cooler uses similar technology developed byBETSCE and the 25K UCSB Long Duration Balloon Cooler35.Creare 35K Single Stage Reverse Brayton or MMRBC. This cooler is being developed byAFRL as a candidate for cooling sensor IRFPAs such as SBIRS LOW. NASA GSFC has alsosupported this technology and is currently using components of the SSRB and MSRB for theNICMOS flight cooler and circulator. The technology involves component improvements overthe SSRB to improve efficiency at lower cooling loads and temperatures. The original programrequirements were changed from providing multi-stage cooling of 0.4 W @ 35 K and 0.6 W @60 K to a single stage providing 1.0 W at 35 K for approximately the same 100 watts of power.The new and smaller components involve using permanent magnets for both the compressormotor (replacing a less efficient induction motor) and cryogenic turboalternator and the use of amore compact recuperator design for the heat exchanger. The turboalternator replaces the SSRBturboexpander allowing reduced parasitics and elimination of brake flow/cooling. This coolerwill be delivered to AFRL for performance and endurance testing.LMMS LADS 35 K Single Stage Stirling. This cooler is a slight modification of the L1710Cwhich is based on previous Lucas-built coolers. The cooler utilizes RAL/Oxford technologysuch as linear motors and spiral-flexure bearing supports to maintain clearance seals in theexpander and back-to-back compressors.The modifications have included improved compressionspace porting and change in position sensor design. Current predictions based on L1710C testdata will provide 0.5 W @ 35 K for a TMU specific power of 138 W/W. Two L1710C unitshave been built but have not been life tested. These units have accumulated a few thousandhours in various lab tests and one Lucas-built cooler has accumulated over 16,000 hours.Control electronics have been flight qualified to provide for cancellation of axial residualvibration and temperature stability of the cold-tip. An LMMS compressor has also demonstratedlow lateral vibrations using tangential-arm flexures in limited testing.TRW 35 K Model PTC-010A-035-I and PTC-020C-035-I Single Stage Pulse Tubes. Thesecoolers were developed under separate AFRL programs and use previously developedtechnology under NASA/DoD contracts. The back-to-back compressors utilize flexure bearingsupports for clearance seals and linear motor compressor drive as do their Stirling counterpartsand are derived from Oxford technology. The pulse tube coolers have been sized to deliver 0.3and 0.85W at 35K. These coolers are currently at AFRL for performance and endurance testing.These units were also performance characterized at JPL. The larger capacity unit hasaccumulated about 5,000 hours while the smaller unit has about 4,000 hours. Control electronicshave been developed and flight qualified for the smaller capacity unit.Raytheon Single Stage Stirling 35 K PSC/SMTS. These TMUs are similar to their SSC/ISSCcounterparts. The SSC was designed under an AFRL development program to provide 2 W @60K. The ISSC was an improved version developed under IRAD and used for early SBIRSLOW life testing at 60 K which accumulated 46,000 hours on two units. Another unitsuccessfully flew on a shuttle mission. The PSC program was initiated in late 1992 but theSMTS began only two years ago. Both units have benefited from numerous improvements toincrease the TMU efficiency. The PSC unit has incorporated tangential-arm flexure springs for12 GOVERNMENT CRYOCOOLER DEVELOPMENT AND TEST PROGRAMSclearance seal support in the back-to-back compressor which has recently been demonstrated atJPL to substantially reduce vibrations in both axial and lateral axes. This Aerospace Corp.tangential-arm design had previously been demonstrated only in flexure module tests and thosementioned for the LMMS compressor. The axial residual vibrations were canceled by controlelectronics feed-back techniques as with other controllers used on the TRW/Ball/LMMS units.The SMTS units incorporate a heat-intercept concept first demonstrated at JPL to substantiallyreduce cold-finger parasitics in Stirling coolers. The PSC will be delivered to AFRL forperformance and endurance testing. An SMTS life test unit for the SBIRS LOW FDS programhas accumulated ~9000 hours. Control electronics for the PSC are flight-type. The flightelectronics for the SMTS coolers are rad-hard and are being flight qualified but are not stand-alone as they are integrated with other payload functions for FDS.50-100 K Operating RangeThe largest group of coolers are in this range with the majority of the units initiallydesigned to operate in the 55 to 75 K range. This area represents the most mature technology.Several coolers have been flown since the early 1990s primarily to support science experimentsor technology demonstrations. Simple flight electronics have been tested and flown. However,fully qualified electronics with integrated vibration control capability have only just begunemerging during the last few years. These are being integrated into flight systems which will belaunched in the near future.Ball 58 K HIRDLS Instrument. Ball began development of Stirling coolers in 1990 withpurchase of a license to build clones of RAL Oxford type coolers. Beginning in 1992, Balldeveloped two lines of single-stage cryocoolers aimed at operation at 60 K. On IRAD, Ball builta series of two improved designs maintaining the RAL heritage. The initial design achieved 1.5Wof cooling at 55 K and is currently on life test at Ball with >23,000 hours. The second versionof this unit (SA160) provides 2.5 W of cooling at 60 K for 116 W to the compressors. Inparallel, Ball developed a single-stage version of its SB230 cryocooler. This cooler is a fixedregenerator design capable of lifting 1.6 W at 60 K for 53 W to the compressor. This cooler isscheduled to fly on the HIRDLS instrument on the NASA EOS Chem Platform in 2002.Ball COOLLAR 65/120K J-T. This program has been in existence for over 5 years andculminated in a successful micro-gravity verification and characterization aboard the SpaceShuttle in August of 1997. The design uses an oil lubricated compressor to provide the highpressure ratio for a multi-stage J-T (with some thermo-electric cooler assisted precooling) coldhead which produces 5 W of cooling at 120 K and an average of 1.25 W at 65 K. Because this J-T cooler produces and stores liquid nitrogen at the cold interfaces, it has the ability to load level avariable load at the 65 K stage. It was thus designed to meet a 65 K load profile with peak loadsof 3.5 W. The cooler was also designed with long flexible lines leading to the J-T cold head toenable the remote mounting of the compressor.Creare 65 K Single Stage Reverse Brayton (SSRB). This cooler was designed for long lifeusing high speed, small turbomachines with gas bearings allowing vibration and wear-freeoperation to provide 5 Wof cooling at 65 K. The cooler consists of small-size precision devices.The cycle operates with continuous flow of neon gas circulated by a compressor through arecuperative heat exchanger and turbine expander. Additional components include a highefficiency inverter/controller, aftercooler and load heat exchanger. This technology has beensupported by both NASA and AFRL. The cooler has achieved its highest efficiency with asystem (cooler and electronics) specific power of 37 W/W for 7.5 watts of cooling @ 65K and aheat rejection temperature of 280 K. The cooler is continuing endurance testing at AFRL andhas accumulated ~25,000 hours.OVERVIEW OF PERFORMANCE OF SPACE CRYOCOOLERS 13Creare 65 K Stirling Diaphragm Cooler (SSC). In the late 1980s both the USAF and BMDOrecognized the need for a long life cryocooler capable of handling small loads in the 50-80Ktemperature range. As part of the general standard spacecraft cooler (SSC) program, Creare wasfunded to develop an alternative technology to the flexure spring cryocoolers being developed byseveral sources. As part of this effort, Creare developed an engineering model of a coolerdesigned to provide 2 W of cooling at 65 The EDM was delivered to the AFRL in early1994 and has accumulated over 10,000 hours of endurance testing after its performance wascharacterized and documented. The program has been completed.Creare 70 K NICMOS (SSRB). The Near-Infrared Camera and Multi-Object Spectrometer(NICMOS) is a second generation Hubble Space Telescope (HST) science instrument whosedetectors are cooled to about 58 K by a solid Nitrogen cryostat. An anomaly discovered in late1997 indicated that the operating life of the dewar would reduce the expected life from 48months to about 1.7 years. As a result the NASA Goddard Spaceflight center (GSFC) decidedto attempt to retrofit the solid cryostat with an improved version of the Creare 5 W SSRB. Thenew cryocooler is designed to provide approximately 7.7 W at 70 K for a total input power ofaround 315 W. The new system along with a newly developed flight electronics package is to beflight tested aboard the STS in late 1998 with final integration into the HST in early 2000.LMMS 1710-C/SCRS Stirling. Since 1987 Lockheed-Martin has been developing advancedcryocooler systems based on the Oxford technology under a teaming arrangement with LucasAerospace (since terminated). Several different models emerged from this activity including the1710-C and SCRS discussed in this paragraph and the LADS unit which was previouslydiscussed. The 1710-C consists of back-to-back compressors connected to a single displacer,providing about 2.0 W at 60 K with a total power input of 130 W including the controlelectronics package which has been flight qualified.Utilizing similar hardware with a slightly larger compressor piston diameter, anintegrated system was developed as the SCRS, funded jointly by several USAF organizations aspart of the SPAS-III flight experiment. Two compressors and two displacers which have theircold tip attached via flex couplings in a common vacuum housing provided about 1.2 W ofcooling at 59 K. This assembly was tested and delivered to the Utah State University for overallsystem testing.Raytheon Stirling 60 K PSC/SMTS/ISSC/SSC. As stated for the Raytheon Stirling 35K units,these coolers have a common TMU heritage (e.g., expander/compressor sizing) in that they wereoriginally designed for cooling 2 W @ 60/65K. Both the PSC and SMTS coolers are the sameunits for 35 and 60 K application. The SMTS unit has a lower cooling requirement for 60Koperation of the same order as the 35K requirement. The SMTS life test cooler has been operatedat 60 K as well as at 35 K mentioned above as part of the ~9000 hours of operation. Also asmentioned above one ISSC has accumulated nearly 24,000 hours while the other life test unitaccumulated 22,000 hours. The respective TMU specific powers for the ISSC and SSC units @65 K are 45 W/W for 1.75 and 1.2 watts. The respective TMU specific powers for the PSC andSMTS (with heat intercept) are 27.5 and 22.4 W/W at 60 K. Without heat intercept the SMTSTMU specific power is about the same as the PSC TMU which does not use the heat intercept,i.e., 27.5 W/W. The ISSC #4 was modified to improve motor efficiency and thermal interfaces.It was also tested under higher charge pressure and achieved improved performance.TRW 60K PTC Models for AIRS, TES, 6020, and IMAS Programs. These coolers in bothintegral (I) and split (S) configurations have been developed for both NASA and Air Forceprograms. They have common heritage to the above mentioned TRW 35K coolers. Two flightmodels of the PTC-010B-055-S (55 K) have been delivered to the NASA AIRS program and twoflight units of the PTC-010C-057-I (57 K) will be delivered to JPL in 1999 for TES. PTC-010A-060-I (60 K) will be delivered as a flight unit to MTI in 1998. An EDM of this unit wasdelivered to AFRL for endurance and performance testing after being performance characterized14 GOVERNMENT CRYOCOOLER DEVELOPMENT AND TEST PROGRAMSat JPL. PTC-004A-055-I will be delivered to JPL in 6/98 as two EDM units for the IMASprogram.TRW 60-150K Integral Miniature Stirling (SC-0-6A-65-I) and Integral Miniature PulseTube (PTC-001A-115-I). These coolers were developed for DOD requirements and have beendelivered for several applications including life testing and optics cooling for SBIRS LOW. Twomini-Stirling coolers were life tested for ~15,000 hours each to provide 0.16 W @ 60 K for aninitial SBIRS LOW IRFPA requirement. The corresponding TMU specific power at 60 K is 88W/W. At the same time TRW ran life tests on two IRAD coolers for the same program, one ofwhich has accumulated ~27,000 hours to date. The Stirling cooler will be a part of the HTSSE-II payload to be launched on the ARGOS spacecraft in December 1998. Two miniature P-Tsare currently operating on the CX payload and have accumulated 3 months of operation.MMS 50-80K Stirling. This cooler is a modification of the single stage 80K cooler formerlyknown as the BAe 80K. The 80K cooler was built and qualified for an ESA contract under alicensing agreement from Oxford University where the original developmental work wasperformed. The heritage of this design is based on two single stage coolers developed by Oxfordand RAL which were flown as part of the Improved Stratospheric and Mesospheric Sounder(ISAMS) instrument aboard the Upper Atmosphere Research Satellite (UARS) in September of1991. These coolers accumulated well in excess of 25,000 hours in orbit. Several ground testunits have accumulated over 50,000 hours each. Also, RAL has built two similar single stagecoolers based on the same RAL/Oxford pressure modulator technology that was flownsuccessfully for up to 7 years in the 1970s before the instruments (Pioneer Venus, Nimbus 6 and7) were turned off. The first unit flew as part of the Along Track Scanning Radiometer (ATSR)instrument aboard the Earth Resources Satellite (ERS-1) in July 1991 and was funded by ESA.The second unit flew on ATSR-2 which replaced ATSR-1. The total flight hours for both RALcoolers have exceeded 60,000 hours.The basic 50-80K unit which is also flight qualified has been made in batches of 15 andas of this writing over 45 units have been manufactured. A number of programs sponsored byboth NASA and ESA are scheduled to fly this unit over the next several years includingMicholson Interferometer for Passive Atmosphere Sounding (MIPAS )and the Measurement forPollution in the Tropopause (MOPITT) instruments. The nominal performance of this unit isusually quoted as 1.7 W at 80 K but it is being used over a wide range of temperatures fromabout 58 K to 90 K. Details of the acceptance and qualification programs are defined by Jones43and Davies27. Individual life test units have accumulated over 20,000 hours.Above 100 KAlthough virtually all of the coolers in the previous two ranges can be operated at muchhigher temperatures, the performance of the TRW Miniature P-T (MPT) and miniature Stirling(MSC) units have been characterized at temperatures up to 150K specifically to be compatiblewith cooling optics, shields , etc. The MPT cooler TMU specific power for 1.5 W @ 115 K is~13.4 W/W. for 2.5 W @ 150 K is 8.2 W/W, and for 1.25 W @ 175 K is 5.8 W/W. The MSCTMU specific power for 0.5 W @ 100 K is 15.5 W/W, for 0.8 W @ 120 K is 9.7 W/W, and for1.3 W @ 150 K is 6.4 W/W. However the Raytheon PSC/ISSC, TRW PTCs, LMMS, Ball andCreare coolers have been proposed and in some cases tested for operation at the 100 to 120 Klevel. For gimbaled optics with limited heat rejection capabilities, projected requirements arecooling loads of 6 to 10 watts at ~100K with TMU specific powers as low as 8 to 10 W/W andlightweight units of 3 to 5 kg. Current performance of the Raytheon PSC and TRW PTs are inthe 12 to 14 W/W range at this temperature with masses over 12 kg. All of the above coolerswould require re-design to meet these 100 K cooling and mass requirements. Because of thisdeficiency, the AFRL has initiated the High Efficiency program to develop technology to meetthe future gimbaled optics requirements.OVERVIEW OF PERFORMANCE OF SPACE CRYOCOOLERS 15SPACE CRYOCOOLER PERFORMANCE COMPARISONMethods and CriteriaThe cryocooler capacity, power efficiency, and mass efficiency data are presented here atreference temperatures of 35, 60, and 100 K. The data was compiled from numerous vendor andgovernment sources1-46. The data was interpolated or normalized to a reference cooling loadtemperature and a 300 K rejection temperature using the following Carnot cycle ratio:where the Q is the cooling capacity and T is the temperature either at the cold tip (ct) or heatrejection (rej) interface. The use of this ratio assumes that the Carnot efficiency (or refrigeratorcoefficient of performance) is the same for both the data and reference conditions. The equationcalculates the cooling capacity at the reference conditions for the same input power as the data.The Carnot ratio was also used to interpolate the upper temperature cooling loads of a fewmultistage cryocoolers to allow a (very) rough comparison to single stage units.There are many caveats to the database. The error associated with the Carnot extrapolationincreases as the data conditions deviate from the reference. For cooling load temperaturedifferences greater than about 5 K or rejection differences greater than about 20 K, the Carnotinterpolation is suspect. Also, because the database for flight quality cryocooler electronicscontrollers is limited, the input power from the electrical bus for most of the data has beenestimated from the measured motor power. A generic electronics estimate of 6 kg with 85%efficiency and 10 W of quiescent power was used for cryocoolers which do not currently haveflight like or flight quality electronics. The estimate of electronic power can easily result ininaccuracies of 5%. Overall, the database is to be used only for approximate ( 10-20% at best)comparisons between cryocoolers.Also, the reference cooling load temperature is at the cryocooler cold block interface, whichcan be significantly (typically 5 K for 1 to 2 W loads) colder than the cooled instrument. Forcryocoolers or applications where the cooler cold head can be directly (without a thermal strap)mounted to the instrument interface, this temperature gradient can be significantly reduced.Because of their long flexible lines from their compressors to the cold head, the Joule-Thomsonand Brayton cycle cryocoolers can more easily be mounted directly to the instrument interface.Thus, the Joule-Thomson and Brayton cryocoolers have the potential to be run at higher (about3-5 K for 1-2 W loads) cold tip temperatures (and, thus, decreased input power and increasedefficiency) while still maintaining the same instrument temperature.Since there are only a few existing flight electronic hardware units, a relative evaluation ofthe cryocooler motor powers is often more accurate than comparing the total input power. Themotor power may be misleading for units or cycles which have significantly different electronicpower requirements. The relative efficiency of the Brayton cryocooler improves using totalpower compared to using only motor power because of less power consumption in theelectronics.Cryocooler Mass and Power Performance at 35, 60, and 100 KFigures 1 and 2 are plots of cryocooler motor specific (input divided by cooling capacity) andtotal (motor and electronics) power, respectively, for cooling at 60 K as a function of cooling16 GOVERNMENT CRYOCOOLER DEVELOPMENT AND TEST PROGRAMSFigure 1. Cryocooler motor specific power Figure 2. Cryocooler total specific powerinterpolated to 60 K cooling and 300 K reject. interpolated to 60 K cooling and 300 K reject.Figure 3. Cryocooler total specific mass Figure 4. Cryocooler motor specific powerinterpolated to 60 K cooling and 300 K reject. interpolated to 35 K cooling and 300 K reject.Figure 5. Cryocooler total specific power Figure 6. Cryocooler total specific massinterpolated to 35 K cooling and 300 K reject. interpolated to 35 K cooling and 300 K reject.OVERVIEW OF PERFORMANCE OF SPACE CRYOCOOLERS 17Figure 7. Cryocooler motor specific power Figure 8. Cryocooler total specific powerinterpolated to 100 K cooling and 300 K reject. interpolated to 100 K cooling and 300 K reject.Figure 9. Cryocooler total specific massinterpolated to 100 K cooling and 300 K reject.capacity. The Figures show the expected effect of efficiency increasing as the capacity increasesand indicate the general trend at 60 K of the higher efficiency at low to medium loads of Stirling(especially the Raytheon PSC) and Pulse Tube cryocoolers compared with the Reverse Brayton.Figure 3 is a plot of cryocooler specific mass (SM or mass divided by cooling capacity) forthe total unit (including electronics) for cooling at 60 K as a function of cooling capacity. Thetrend of increased mass efficiency with increased capacity is indicated. The light weight natureof the Brayton cryocoolers and the TRW IMAS design is also apparent.Figures 4 to 6 and 7 to 9 are similar plots of the specific power and mass as a function ofcooling capacity for cooling at 35 K and 100 K, respectively. Of significance at 35 K is thepotential (based only on component tests) improved relative performance of the recuperativeBrayton cycle Creare MMRBC at lower temperatures. At 100 K, if successful, the new startAFRL High Efficiency program with goals of less than 10 W/W motor power and less than 1kg/W total mass for 10 Wof cooling should make significant advances over the state of the art.SUMMARYAn overview is presented of the status and performance for a wide range of long lifecryocoolers being developed for space applications ranging in temperature from 10 K to at least100 K. This survey identifies more than 30 coolers covering a variety of thermodynamic cyclesand cooler types with capacities from a few milliwatts to over 10 W and includes single andmulti-stage designs. The survey indicates that more than a dozen coolers are at or near flightmodel status and are undergoing flight qualification to be available for space applications beforethe turn of the century. Performance comparisons were made using plots of specific power and18 GOVERNMENT CRYOCOOLER DEVELOPMENT AND TEST PROGRAMSspecific mass as a function of capacity at temperatures of 35, 60, and 100 K. The comparisonsshow the relatively higher efficiencies of Stirling and Pulse Tube cycles near 60 K, the increasedefficiency of all units with increasing capacity, and the potential increase in both power and massefficiency for the new start AFRL High Efficiency program.ACKNOWLEDGMENTThe authors wish to acknowledge the support of personnel at the Air Force Research Lab andthe Ballistic Missile Defense Organization. Special thanks are given to J. P. Reilly and Lt. B. J.Tomlinson of AFRL, S. Bard, B. Bowman, R. Ross, Jr., and L. Wade of the Jet Propulsion Lab,R. Fernandez, W. Gully, W. Kiehl, R. Levenduski, and R. Reinker of Ball, W. Swift of Creare,D. Gilman and K. Price of Raytheon, T. Nast and I. Spradley of Lockheed Martin, B. G. Jones ofMatra Marconi Space, and C. K. Chan and M. Tward of TRWfor providing a large portion of thecryocooler data presented here.REFERENCES1. Gully, W., Personal Communication, Ball Aerospace and Technology, Boulder, Colorado (5 April1998).2. Horsley, W. J., Test Results for the Ball Single-Stage Advanced-Flight Prototype Cryocooler,Cryocoolers 9, R. G. Ross, Jr., Ed., Plenum Press, New York (1997), pp. 55-58.3. Horsley, W. J., Test Results for Single-Stage Ball Flight Prototype Cooler, Cryocoolers 8, R. G.Ross, Jr., Ed., Plenum Press, New York (1995), pp. 23-33.4. Carrington, H., et al., Multistage Coolers for Space Applications, Cryocoolers 8, R. G. Ross, Jr.,Ed., Plenum Press, New York (1995), pp. 93-102.5. Berry D., System Test Performance for the Ball Two-Stage Stirling Cycle Cryocooler, Cryocoolers9, R. G. Ross, Jr., Ed., Plenum Press, New York (1997), pp. 69-77.6. Levenduski, R. and R. Scarlotti, Joule-Thomson Cryocooler Development at Ball Aerospace,Cryocoolers 9, R. G. Ross, Jr., Ed., Plenum Press, New York (1997), pp. 493-508.7. Levenduski, R., et al., Hybrid 10 K cooler for Space Applications, to be presented at ICCC #10,Monterey, California (26-28 May 1998), paper #37.8. Fernandez, R., Flight Demonstration of the Ball Aerospace Joule-Thomson Cryocoolers, to bepresented at ICCC #10, Monterey, California (26-28 May 1998), paper #57.9. Stacy, W. D., Development and Demonstration of the Creare 65 K Standard Spacecraft Cooler,Cryocoolers 9, R. G. Ross, Jr., Ed., Plenum Press New York, (1997), pp. 45-53.10. Tomlinson, 1st. Lt. B. J., Personal Communication, Air Force Research Laboratory, Kirtland AirForce Base, Albuquerque, New Mexico (January 1998).11. Levenduski, R., Joule-Thomson Cryocooler Development at Ball Aerospace, Cryocoolers 8, R. G.Ross, Jr., Ed., Plenum Press, New York (1995), pp. 543-558.12. Swift, W. L., Single-Stage Reverse Brayton Cryocooler: Performance of the Engineering Model,Cryocoolers 8, R. G. Ross, Jr., Ed., Plenum Press, New York (1995), pp. 499-506.13. Nellis, G., et al., Design and Test of a Low Capacity Reverse Brayton Cryocooler for Refrigerationat 35 K, to be presented at ICCC #10, Monterey, California (26-28 May 1998), paper #36.14. Dolan, F., et al., Reverse Brayton Cooler for NICMOS, to be presented at ICCC #10, Monterey,California (26-28 May 1998), paper #54.15. Bard, S., Flight Demonstration of a 10 K Sorption Cryocooler, Cryocoolers 9, R. G. Ross, Jr., Ed.,Plenum Press, New York (1997), pp. 567-576.16. Wade, L., Continuous and Periodic Sorption Cryocoolers for 10 K and Below, Cryocoolers 9, R. G.Ross, Jr., Ed., Plenum Press, New York (1997), pp. 577-586.17. Bowman, R., Personal Communication, Jet Propulsion Laboratory, Pasadena, California (February1998).18. Chan, C. K., et al., Performance of the AIRS Pulse-Tube Engineering Model Cryocooler,Cryocoolers 9, R. G. Ross, Jr., Ed., Plenum Press, New York (1997), pp. 195-212.19. Ross, Jr., R. G., AIRS Cryocooler Systems Design and Development, Cryocoolers 9, R. G. Ross,Jr., Ed., Plenum Press, New York (1997), pp. 885-904.OVERVIEW OF PERFORMANCE OF SPACE CRYOCOOLERS 1920. Chan, C. K. , Personal Communication, TRW, Redondo Beach, California (5 April 1997).21. Burt, W. W., New Mid-Size High Efficiency Pulse-Tube Coolers, Cryocoolers 9, R. G. Ross, Jr.,Ed., Plenum Press, New York (1997), pp. 173-182.22. Johnson, D. L., Performance Characterization of the TRW 3503 and 6020 Pulse-Tube Coolers,Cryocoolers 9, R. G. Ross, Jr., Ed., Plenum Press, New York (1997), pp. 183-193.23. Tward, E., Miniature Long-Life Space Qualified Pulse-Tube and Stirling Cryocoolers, Cryocoolers8, R. G. Ross, Jr., Ed., Plenum Press, New York (1995), pp. 329-336.24. Burt, W. W., Demonstration of a High Performance 35 K Pulse-Tube, Cryocoolers 8, R. G. Ross,Jr., Ed., Plenum Press, New York (1995), pp. 313-319.25. Nast, T., Personal Communication, Lockheed Martin Missiles and Space, Organization H1-21, PaloAlto, California (15 April 1998).26. Jones, B. G., Personal Communication, Matra Marconi Space, Filton, Bristol, England (20 April1998).27. Davies, S. W., Product Specification, 50-80 K Mechanical Cooler, Doc. Ref. no.PSP/MCC/A0426/MMB, (27 October 1997).28. Scull, S. R., Design and Development of a 20 K Stirling Cooler for FIRST, Cryocoolers 9, R. G.Ross, Jr., Ed., Plenum Press, New York (1997), pp. 89-96.29. Jones, B. G., Qualification of a 4 K Mechanical Cooler for Space Applications, Cryocoolers 8, R.G. Ross, Jr., Ed., Plenum Press, New York (1995), pp. 525-536.30. Bradshaw, T. M., Life Test and Performance Testing of a 4 K Cooler for Space Qualifications, tobe presented at ICCC #10, Monterey, California (26-28 May 1998), paper #73.31. Johnson, D. L., EMI Performance of the AIRS Cooler and Electronics, to be presented at ICCC#10, Monterey, California (26-28 May 1998), paper #77.32. Chan, C. K., IMAS Pulse-Tube Cooler Development and Testing, to be presented ICCC #10,Monterey, California (26-28 May 1998), paper #104.33. Spradley, I. and T. Nast, Personal Communication, Lockheed Martin Missiles and Space, Palo Alto,California (10 April 1998).34. Longsworth, R. C., Periodic 10 K J-T Cryostat for Flight Demonstration, to be presented at ICCC#10, Monterey, California (26-28 May 1998), paper #8.35. Levy, A. R., Performance of a 25 Kelvin Sorption Cryocooler Designed for the UCSB LongDuration Balloon Cosmic Microwave Background Radiation Experiment, to be presented ICCC#10, Monterey, California (26-28 May 1998), paper #7.36. Gilman, D., Personal Communication, Raytheon Systems Co., El Segundo, California (21 April1998).37. Price, K., Personal Communication, Raytheon Systems Co., El Segundo, California (21 April 1998).38. Roberts, T. and J. Bruning, Hughes Aircraft Co. Standard Spacecraft Cooler Acceptance Testing andPerformance Mapping Results, Phillips Laboratory Report #PL-TR-96-1163 (November 1996).39. Tward, E., Personal Communication, TRW, Redondo Beach, California (21 April 1998).40. Swift, W., Personal Communication, Creare, Inc., Hanover, New Hampshire (20 April 1998).41. Nast, T., Design, Performance, and Testing of the Lockheed Developed Mechanical Cryocooler,Cryocoolers 8, R. G. Ross, Jr., Ed., Plenum Press, New York (1995), pp. 55-67.42. Spradley, I. E. and W. G. Foster, Space Cryogenic Refrigerator System (SCRS) ThermalPerformance Test Results, Cryocoolers 8, R. G. Ross, Jr., Ed., Plenum Press, New York (1995), pp.13-22.43. Jones, B. G., et al., The Batch Manufacturing of Stirling Cycle Coolers for Space ApplicationsIncluding Test Qualification and Integration Issues, Cryocoolers 9, R. G. Ross, Jr., Ed., PlenumPress, New York (1997), pp. 59-68.44. Petree, D. and P. V. Mason, Infrared Astronomical Satellite (IRAS) Superfluid Helium TankTemperature Control, Adv. Cryo Engr, V. 29 (1983), pp. 661-667.45. Volz, S. M., et al., Cryogenic On-Orbit Performance of the NASA Cosmic Background Explorer(COBE), SPIE Conference, San Diego, California (July 1990).46. Bejan, A., Entropy Generation Minimization, CRC Press, New York (1996).Air Force Research LaboratoryCryocooler Technology DevelopmentThomas M. Davis, John Reilly, and First Lt. B. J. Tomlinson, USAFAir Force Research LaboratoryKirtland AFB, NM 87117-5776ABSTRACTThis paper presents an overview of the cryogenic refrigerator and cryogenic integrationprograms in development and characterization under the Cryogenic Technology Group, SpaceVehicles Directorate of the Air Force Research Laboratory (AFRL). The vision statement for thegroup is to support the space community as the center of excellence for developing and transi-tioning space cryogenic thermal management technologies. The primary customers for theAFRL cryogenic technology development programs are Ballistic Missile Defense Organization(BMDO), the Air Force Space Based Infrared System (SBIRS) Low program office, and otherDoD space surveillance programs.This paper will describe the range of Stirling, pulse tube, reverse Brayton, Joule-Thomsoncycle cryocoolers, and sorption cryocoolers currently under development to meet current andfuture Air Force and DoD requirements. The AFRL customer single stage cooling requirementsat 10 K, 35 K, 60 K, 150 K, and multi-stage cooling requirements at 35/60 K are addressed. Inorder to meet these various requirements, the AFRL Cryogenic Technology Group is pursuingvarious strategic cryocooler and cryogenic integration options.The Air Force Research Laboratory is also developing several advanced cryogenic integra-tion technologies that will result in the reduction in current cryogenic system integration penal-ties and design time. These technologies include the continued development of the CryogenicSystems Integration Model (CSIM), 60 K and 100 K thermal storage units and heat pipes, cryo-genic straps, thermal switches, and development of an Integrated Lightweight Cryogenic Bus(CRYOBUS).INTRODUCTIONThe use of long-life, active cryocoolers provides a significant improvement to DoD spacesurveillance and missile tracking missions. Cooling of infrared sensors in space at temperaturesof 80 K and below has mainly been accomplished using stored cryogens. These expendablecryogenic systems require the launch of heavy and complex dewars, which at best have a one ortwo year life. Cooled detectors allow vast improvements in identification and discriminationCryocoolers 10, edited by R. G. Ross, Jr.Kluwer Academic/Plenum Publishers, 1999 2122 GOVERNMENT CRYOCOOLER DEVELOPMENT AND TEST PROGRAMScapability with a minimum of sensor apecture growth. Smaller apecture produces cheaper,lighter sensors; much easier to host in a space-based environment. Other space missions such ascommunications, remote sensing, and weather monitoring can benefit from subsystems usingcryogenic technology including super conducting electronics, high data rate signal processors,and high speed/low power analog to digital converters.The objective of the Air Force Research Laboratory cryocooler effort is to develop anddemonstrate space qualifiable cryogenic technologies required to meet future requirements forAir Force and Department of Defense (DoD) missions. Pursuant of this objective, the Air ForceResearch Laboratory characterizes and evaluates the performance of development hardware,pursue advanced concepts for future spacecraft missions, and work to enhance cryocooler tospacecraft integration. Cryocooler development is considered a Military Critical Technologyand is also tracked under the Defense Technology Objectives initiative. Performance improve-ment objectives have been established for life, power, mass, and vibration. Progress is reviewedannually at DoD level. Collaboration with other government development activities and privateindustry has been a major strength of the AFRL program. This has resulted in leveraging ofscarce development funding and more rapid transition of cryocooler technology to the spacecommunity.Current AFRL cryocooler development programs include Stirling, pulse tube, reverseBrayton, Joule-Thomson, and sorption machines that produce cooling in the 10 K through 150K temperature range. Compared with state-of-the-art dewars and cryogenic radiators, mechani-cal cryocoolers offer space systems significant weight savings, performance improvements, andlong life potential (greater than 5 years).After a specific cryocooler is developed, the unit is subjected to acceptance, characteriza-tion, and endurance tests based on customer and Air Force requirements. Acceptance tests areperformed to determine if the unit meets contractual specifications. Characterization is then per-formed to determine the operating performance envelope of the cryocooler in nominal and offnominal conditions. Endurance tests are used to demonstrate operational hours, and identify andcharacterize long term, life limiting failure mechanisms and long term performance degradation.Components that significantly improve the efficiency, extend life, reduce mass, or limit in-duced vibration are developed and transitioned into next generation cryocooler designs. Thesetechnologies are typically developed under contractor sponsored In-house Research and Devel-opment (IRAD) efforts or from the Small Business Innova