CRYOGENICS

CRYOCOOLERS10A publication of theInternationalCryocooler ConferenceCRYOCOOLERS10Edited byR.G.Ross,Jr.Jet Propulsion LaboratoryCaliforniaInstitute 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 applicationswith the development of matureproducts addressed to a wide variety of operating temperatures. On the commercial front, Gifford-McMahoncryocoolerswithrareearthregeneratorscontinuetomakegreatprogressinopeningupthe4Kmarket.Alsointhecommercialsector,continuedinterestisbeingshowninthedevelopment of long-life,low-cost cryocoolersfor theemerginghigh temperaturesuperconduc-torelectronicsmarket,particularlythecellulartelephonebase-stationmarket.Athighertem-perature levels,closed-cycleJ-Torthrottle-cyclerefrigeratorsaretaking advantageofmixedrefrigerant 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, butcontinuetoshrink in numbersas thedefenseindustry continuesitsconsolidation.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,Cryocoolers10 isbasedontheircontributionsat the10thInternationalCryocoolerConference,heldinMonterey,California,inMay1998.Theprogramofthisconferencecon-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 tothe public in hardcover book form since1994.This book isthus the third volumeinthis newseries of hardcover textsfor usersand developersof 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.EightofthesecoverkeyaccomplishmentsoftheSpecialResearchandDevelopmentBureau(SR&DB) in Cryogenic Technology of the Institute for Low Temperature Physics and Engineer-ingoftheNationalAcademyofSciencesintheUkraine;theyarelistedinthesubjectindexunder:SR&DBof theUkraine.Also,two articlesauthored bystaff of theKharkovStatePoly-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 centersinthe formerUSSR andthe broader worldwide cryocooler community.Because this book is designed to be an archival reference for users of cryocoolers as much asfordevelopersof cryocoolers,extra efforthasbeenmadetoprovideathorough SubjectIndexthat covers the referenced cryocoolers by type and manufacturers name, as well as by the scien-tificorengineeringsubjectmatter.Extensivereferencingoftestandmeasurementdata,andapplicationandintegrationexperience,isincludedunderspecificindexentries.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,aseparate Author Indexis provided, listing all authors and coauthors.Priorto1994,proceedingsof theInternationalCryocoolerConferencewerepublishedasinformalreportsbytheparticulargovernmentorganizationsponsoringtheconferencetypi-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 inlimitedquantity and areout of print at thistime.Thecontentof Cryocoolers10 isorganizedinto15chapters,startingfirstwithanintroduc-torychapter providingcooler overviewsandsummariesof major government cryocoolerdevel-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 to10 K range are covered next, followed by a glimpse into the future with miniature solid-staterefrigeratorsandadvancedrefrigerationcycles.Thelast threechaptersdealwithcryocoolerintegration technologies and experience to date in a number of representative applications.Thearticlesintheselastthreechapterscontainawealthofinformationforthepotentialuserofcryocoolers,as well asfor the developer.It is hoped that this book will serve as a valuable source of reference to all those faced withthechallengesoftakingadvantageoftheenablingphysicsofcryogenicstemperatures.Theexpanding availability of low-cost, reliable cryocoolers is making major advances in a number offields.Ronald G.Ross,Jr.JetPropulsionLaboratoryCaliforniaInstituteofTechnologyAcknowledgmentsThe International Cryocooler Conference Board wishes to thank Lockheed Martin AdvancedTechnology Center, which hosted the 10th ICC, and to express its deepest appreciation to theConferenceOrganizingCommittee,whosemembersdedicatedmanyhourstoorganizingandmanaging 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.PUBLICATIONSRonRoss, Jet Propulsion LabTREASURERRay Radebaugh, NISTPROGRAM COMMITTEEJohn Brisson, MITWilliam Burt, TRWDavid Glaister, Aerospace Corp.Geoffrey Green,NSWCTom Kawecki, NRLLawrence Wade, JPLADVISORYBOARDStephencastles,NASA/GSFCChris Jewell, ESARalph Longsworth, APD CryogenicsYoichi Matsubara,Nihon Univ., JapanMartin Nisenoff, NRLMarko Stoyanof, AFRLWalter Swift,CreareInc.Klaus Timmerhaus, U. of ColoradoJiaHuaXiao,NISTIn addition to the Committee and Board,key staff personnel made invaluable contributions tothepreparationsandconductoftheconference.SpecialrecognitionisdueC.Stoyanof,C.Seeley, J. M. Lee, C. Nast, and C. Kerney.viiContentsGovernmentCryocoolerDevelopment and Test Programs1An Overview of the Performance and Maturity of Long Life Cryocoolers forSpace Applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D.Glaister,The Aerospace Corp.,Albuquerque,NM; M.Donabedian and D.Curran,TheAerospaceCorp.,El Segundo,CA; and T.Davis,AFRL,Kirtland AFB,NMAirForceResearchLaboratory CryocoolerTechnologyDevelopment. . . . . . . .T.M.Davis,J.Reilly,and Lt.B.J.Tomlinson,AFRL,Kirtland AFB,NMEnduranceEvaluationofLong-LifeSpaceCryocoolersatAFRL an Update . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Lt.B.J.Tomlinson,AFRL,Kirtland AFB,NM;and A.Gilbert and J.Bruning,NRC,Albuquerque,NMDARPALowCostCryocoolerPerformance Testing:PreliminaryResults. . . .T.G.Kawecki,NRL,Washington,DC; and S.C.James,AlliedSignalTech.ServicesCorp.,CampSprings,MDDevelopmentof CryogenicCoolingSystemsattheSR&DBintheUkraine..S.I.Bondarenko and V.F.Getmanets,SR&DB,Kharkov,Ukraine121334355Stirling Cryocooler Developments59Qualification Test Results for a Dual-Temperature Stirling Cryocooler ......W.J.Gully,H.Carrington and W. Kiehl,Ball Aerospace &Tech.Corp.,Boulder,CO; andT.Davisand B.J.Tomlinson,AFRL,Kirtland AFB,NMProgresstowardstheDevelopmentof a10K ClosedCycleCoolerfor Space Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A.H.Orlowska and T.W.Bradshaw,RAL,Didcot,UK;S.Scull,MMS,Bristol,UK;andLt.B.J.Tomlinson,AFRL,Kirtland AFB,NMDevelopmentof aLightWeightLinearDriveCryocoolerforCryogenicallyCooledSolidStateLaserSystems. . . . . . . . . . . . . . . . . . . . . . . . .L.B.Penswick,STC,Kennewick,WA;and B.P.Hoden,DecadeOptical Systems,Inc.,Albuquerque,NMLow-WeightandLong-Life65KCooler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .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 Instruments1-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 Developments119AIRS 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, NMIMASPulseTubeCoolerDevelopmentandTesting. . . . . . . . . . . . . . . . . . . . . . .C.K.Chan,T. Nguyen, R.Colbert,andJ. 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 andY.M.Kang,DaikinIndus.,Tsukuba,Japan;andY.Matsubara,NihonUniv.,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.MartinandC.M.Martin,MesoscopicDevices,Golden,CO;and J.Corey,CFIC,Troy,NYDesignand Preliminary Testing of BEIsCryoPulse1000,theCommercialOneWattPulse TubeCooler. . . . . . . . . . . . . . . . . . . . . . . . . . . .S. W.K.Yuan,D. T.Kuo,and A.S.Loc,BEI Technologies,Slymar,CA119129139149157163171181191CONTENTSxiPulse TubeCryocoolerConfigurationInvestigations197Optimal 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.ofSci.,Beijing,ChinaPerformances of Two Types of Miniature Multi-Bypass Coaxial Pulse TubeRefrigerators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .J.T.Liang,J.H.Yang,W.X.Zhu,Y.Zhou,andY.L.Ju,Cryogenics Lab,Chinese Acad.ofSci.,Beijing,ChinaDevelopment of a 5 to 20 W at 80 K GM Pulse Tube Cryocooler . . . . . . . . . . . . .S.Fujimoto andY.M.Kang,MEC Lab,DaikinIndus.,Tsukuba,Japan;andY.Matsubara,NihonUniv.,Funabashi,JapanConceptual Design of Space Qualified 4 K Pulse Tube Cryocooler. . . . . . . . . .G.R.Chandratilleke,Y.Ohtani,H.Nakagome,and K.Mimura,ToshibaCorp.,Kawasaki,Japan;N.YoshimuraandY.Matsubara,NihonUniv.,Funabashi,Japan; H.Okuda,ISAS,Sagamihara,Japan;and T.Iida and S.Shinohara,NASDA,Tsukuba,JapanPerformance Dependence of 4K Pulse Tube Cryocooler onWorkingPressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .N.Yoshimura,S.L.ZhouandY.Matsubara,NihonUniv.,Funabashi,Japan;G.R.Chandratilleke,Y.Ohtani,and H.Nakagome,Toshiba R&DCenter,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,andJ.J.Wang,Cryogenics Lab, Chinese Acad. ofSci.,Beijing,ChinaExperimental Investigation of a Unique Pulse Tube Expander Design. . . . . . .C.S.Kirkconnell,Raytheon SystemsCo.,El Segundo,CAAn ExperimentalStudy on the Heat Transfer Characteristicsof theHeat Exchangers in the Basic Pulse Tube Refrigerator. . . . . . . . . . . . . . . . . .S.Jeongand K.Nam,Korea Adv.InstituteofSci.andTech.,Taejon,KoreaDouble Vortex Tube as Heat Exchanger and Flow Impedance for aPulse Tube Refrigerator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .M.P.Mitchell,Mitchell/Stirling,Berkeley,CA;D.Fabris,IllinoisInst.ofTech.,Chicago,IL;and B.J.Tomlinson,AFRL,Kirtland AFB,NMInvestigationsonRegenerativeHeatExchangers . . . . . . . . . . . . . . . . . . . . . . . . . .I.Rhlichand H.Quack,Univ.ofDresden,Dresden,GermanyPressureDropinPulseTubeCoolerComponents . . . . . . . . . . . . . . . . . . . . . . . . .H.E.Chen,J.M.Bennett,S.Yoshida,A.Le,and T.H.K.Frederking,UCLA,LosAngeles, CA197205213221227233239249257265275PulseTubeFlowandOperationalStabilityInvestigations281ExperimentalResults onInertance and Permanent FlowinPulse Tube Coolers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .L.Duband,I.Charles,A.Ravex,and L.Miquet,CEA/DRFMC,Grenoble,France;andC.I.Jewell,ESA-ESTEC,Noordwijk,TheNetherlands281xii 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,JapanObservationof DC Flows in a Double Inlet PulseTube . . . . . . . . . . . . . . . . . . .V. Kotsubo, P. Huang, and T.C. Nast, Lockheed Martin ATC, Palo Alto, CASuppressionof AcousticStreaming in Tapered Pulse Tubes . . . . . . . . . . . . . . . .J.R.Olson,Lockheed Martin ATC,Palo Alto,CA;andG. W.Swift,Los Alamos Nat1 Lab.,Los Alamos, NMPerformanceofaTaperedPulseTube. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .G.W.Swift,M.S.Allen, and J.J. Wollan, Cryenco Inc., Denver, CONumericalStudyofPulseTubeFlow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Y.Hozumi,ChiyodaCorp.,Yokohama,Japan;M.Murakami,Univ.ofTsukuba,Tsukuba,Japan;andT.Iida,NASDA,Tsukuba,JapanVisualization Study of theLocalFlow Field in anOrifice andDouble-InletPulseTubeRefrigerator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .M.Shiraishi and A.Nakano,Mech.Engin.Lab,Tsukuba,Japan;andN.Nakamura,K.Takamatsu,andM.Murakami, Univ.ofTsukuba,Tsukuba,JapanStability Study of Coaxial Pulse Tube Cooler Driven byAirConditioningCompressor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .L.W.Yang,J.T.Liang,Y.Zhou,P.S.Zhang,W.X.Zhu,and J.H.Cai, Cryogenics Lab,Chinese Acad.ofSci.,Beijing,ChinaGasContaminationEffectsonPulseTubePerformance. . . . . . . . . . . . . . . . . . .J.L.Hall and R.G.Ross,Jr.,JPL,Pasadena,CA291299307315321329337343PulseTubeModelingandDiagnosticMeasurements351Simple Two-Dimensional Corrections for One-DimensionalPulse Tube Models. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .J.M.LeeandP.Kittel,NASAARC,MoffettField,CA;K.D.Timmerhaus,Univ.ofColo-rado,Boulder,CO;and R.Radebaugh,NIST,Boulder,COPulseTubeDevelopmentUsingHarmonicSimulations. . . . . . . . . . . . . . . . . . .H.W.G.Hooijkaas,EindhovenUniv.ofTech.;and A.A.J.Benschop,Signaal-USFA,Eindhoven, The NetherlandsAnalysis of a Two Stage Pulse Tube Cooler by Modelingwith ThermoacousticTheory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A.Hofmann,ForschungszentrumKarlsruhe,Karlsruhe,Germany;and S.Wild,Univ.ofKarlsruhe,Karlsruhe,GermanyModeling Pulse Tube Coolers with the MS*2Stirling Cycle Code. . . . . . . . . .M.P.Mitchell,Mitchell/Stirling,BerkeleyCA;and L.Bauwens,Univ.ofCalgary,CalgaryCanadaExperimental Verificationof a Thermodynamic Modelfor aPulse TubeCryocooler. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .J.Yuanand J.M.Pfotenhauer,Univ.ofWisconsin,Madison,WI351359369379387CONTENTSxiiiMeasurements of Gas Temperature in a Pulse Tube Using thePlanar Laser Raleigh Scattering Method. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .K.Nara,Y.Hagiwara,and S.Ito,Adv.MobileTelecommunicationTech.Inc.,Aichi-ken,JapanMathematicalModelof aWaveCooler. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .V.N.Kukharenko,KharkovStatePolytechnicUniv.,Kharkov,UkrainePulse Tube Modeling as a Means of Teaching the Design ofCryogenicRefrigerators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .V.N.Kukharenko,KharkovStatePolytechnicUniv.,Kharkov,Ukraine395405413BraytonCryocooler Developments421Design and Test of Low Capacity Reverse Brayton Cryocooler forRefrigerationat35 K and60 K. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .J.McCormick,G.Nellis,W.Swift,and H.Sixsmith,CreareInc.,Hanover,NH;andJ.Reilly,AFRL,Kirtland AFB,NMReverseBraytonCryocoolerforNICMOS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .G.Nellis,F.Dolan,J.McCormick,W.Swift,and H.Sixsmith,Creare Inc.,Hanover,NH;and J.Gibbon and S.Castles,NASAGSFC,Greenbelt,MDDesign and Qualification of Flight Electronics for the HST NICMOSReverseBraytonCryocooler. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C.Konkel andW.Bradley,Orbital SciencesCorp.,Greenbelt,MD;and R.Smith,NASAGSFC,Greenbelt,MD421431439J-TandThrottle-CycleCryocoolerDevelopments449Flight Demonstration of theBall Joule-ThomsonCryocooler. . . . . . . . . . . . . .R.Fernandez and R.Levenduski,Ball Aerospace&Tech.,Boulder,CODesign Optimization of the Throttle-Cycle Cooler with MixedRefrigerant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .M.Boiarski,A.Khatri,APDCryogenics,Allentown,PA; andV.Kovalenko,Moscow PowerEngin.Inst.,Moscow, RussiaLong-LifeCryocoolerfor84-90K. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .V.T.Arkhipov,A.V.Borisenko,V.F.Getmanets,R.S.Mikhalchenko and L.V.Povstiany,SR&DB,Kharkov,Ukraine; andH.Stears,Orbita,Ltd.,Kensington,MDMixedGas J-TCryocoolerwithPrecooling Stage. . . . . . . . . . . . . . . . . . . . . . . .A.Alexeev,Ch.Haberstroh,and H.Quack,Univ.of Dresden,GermanyExperimentalComparison 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.ofSci.,Beijing,ChinaMulticomponentGas Mixturesfor 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,MD449457467475481487xivCONTENTSAn ExperimentalStudy and NumericalSimulation of Two-Phase Flowof Cryogenic Fluids through Micro-Channel Heat Exchanger. . . . . . . . . . . .W.W.Yuen,UCSB,Santa Barbara,CA; andI.C.Hsu,Lockheed Martin ATC,Palo Alto,CA497HybridJ-TCryocoolerSystemsforOperationat4-10K505Hybrid10KCryocoolerforSpaceApplications. . . . . . . . . . . . . . . . . . . . . . . . . .R.Levenduski,W.Gully, and J. Lester, Ball Aerospace & Tech., Boulder, CODesign and Developmentof a 4 K MechanicalCooler. . . . . . . . . . . . . . . . . . . . .S.R.Scull and B.G.Jones,MMS,Bristol,UK;T.W.Bradshaw and A.H.Orlowska,RAL,Chilton,UK;andC.I.Jewell,ESA-ESTEC,Noordwijk,The NetherlandsLife Test and Performance Testing of a4 K Cooler for SpaceApplications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .T.M.Bradshaw,A.H.Orlowska,RAL,Chilton,UK;andC.I.Jewell,ESA-ESTEC,Noordwijk,TheNetherlandsLong-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,MD505513521529SorptionCryocooler Developments535Periodic10 K J-T Cryostat for Flight Demonstration. . . . . . . . . . . . . . . . . . . . .R.C.Longsworth,A.Khatri,and D.Hill,APDCryogenics,Allentown,PACharacterization of Porous Metal Flow Restrictors for Use as theA.R.Levy,UCSB,SantaBarbara,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,CAFastGas-GapHeatSwitchforaMicrocooler. . . . . . . . . . . . . . . . . . . . . . . . . . . .J.F.Burger,H.J.Holland,H.van Egmond,M.Elwenspoek,H.J.M.ter Brake,andH. Rogalla, Univ. of Twente, The Netherlands535545553565GMRefrigeratorsandLow-TemperatureRegenerators575Developmentof a HighEfficiency 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,SumitomoHeavyInd.PPD,Tokyo,JapanDevelopment of a HighEfficiency 4 K GM Refrigerator. . . . . . . . . . . . . . . . .Y.Ohtani,H.Hatakeyama,and H.Nakagome,Toshiba R&DCenter,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.ofTech.,Yokohama,Japan;andY.Ohtani,H.Hatakeyama,and H.Nakagome,ToshibaCorp.,Kawasaki,JapanNumericalSimulationof 4 K GMRefrigerator . . . . . . . . . . . . . . . . . . . . . . . . . .T.Inaguchi,M.Nagao,K.Naka,and H.Yoshimura,Mitsubishi ElectricCorp.Adv.Tech.R&DCenter,Hyogo,JapanNumericalFluidAnalysisofPumping Loss. . . . . . . . . . . . . . . . . . . . . . . . . . . . .K. Naka, T. Inaguchi, M. Nagao, and H. Yoshimura, Mitsubishi Electric Corp. Adv. Tech.R&DCenter,Hyogo,JapanMultilayer Magnetic Regenerators with an Optimum Structurearound4.2K. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .H.Nakane,T.Hashimoto,andY.Miyata,KogakuinUniv.,Tokyo,Japan; M.Okamuraand H.Nakagome,ToshibaCorp.,Kanagawa,JapanAdvancesinNeodymium RibbonRegenerator Materials. . . . . . . . . . . . . . . . . .T.Felmley,Concurrent Tech.Corp.,Johnstown,PAGd-Zn Alloys as Active Magnetic Regenerator Materials forMagneticRefrigeration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .V.K.Pecharsky and K.A.Gschneidner,Jr.,Ames Lab,Iowa StateUniv.,Ames,IAMagnetocaloricPropertiesofGd3Al2................................................V.K.Pecharskyand K.A.Gschneidner Jr.,Ames Laboratory,IowaStateUniv.,Ames,IA;and S. Y.Dankov and A.M.Tishin,Moscow StateUniv.,Moscow,Russia587593603611621629639Advanced RefrigerationCycles and Developments647Development of a Dilution Refrigerator for Low-TemperatureMicrogravityExperiments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P.R.Roach,NASAARC,Moffett Field,CA;and B.Helvensteijn,SterlingSoftware,RedwoodShores, CAPreliminary Experimental Results Using a Two Stage SuperfluidStirlingRefrigerator. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A.B.Patel and J.G.Brisson,MIT,Cambridge,MAInvestigationofMicroscaleCryocoolers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .J.M.Shire,A.Mujezinovic,and P.E.Phelan,ASU,Tempe,AZ647655663CryocoolerIntegrationandTest Technologies671Development of Advanced Cryogenic Integration Solutions. . . . . . . . . . . . . . .D.BugbyandC.Stouffer,Swales Aerospace,Beltsville,MD;T.Davis,Lt.B.J.Tomlinson,and Lt.M.Rich,AFRL,Kirtland AFB,NM;J.Ku and T.Swanson,NASAGSFC,Greenbelt,MD;and D.Glaister,The AerospaceCorp.,Albuquerque,NMCold Accumulators as a Way to Increase Lifetime andCryosystem Temperature Range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .V.T.Arkhipov,V.F.Getmanets,A.Y.Levin,andR.S.Mikhalchenko,SR&BD,Kharkov,Ukraine;and H.Stears,Orbita Ltd,Kensington,MD671689xvi CONTENTSTest Resultsof a Nitrogen Triple-Point ThermalStorage Unit. . . . . . . . . . . . .B.G.Williams and I.E.Spradley,Lockheed Martin ATC,Palo Alto,CAOptimal Integrationof Binary CurrentLead and Cryocooler. . . . . . . . . . . . . .H.M.Chang,HongIkUniv.,Seoul,Korea;and S. W.VanSciver,Natl HighMagnetic FieldLab,Tallahassee,FLCryogenicSystemsIntegration Model(CSIM). . . . . . . . . . . . . . . . . . . . . . . . . . .S.D.Miller and M.Donabedian,The AerospaceCorp.,ElSegundo,CA;and D.S.Glaister,The AerospaceCorp.,Albuquerque,NMHeatRejectionEffectsonCryocoolerPerformance Prediction. . . . . . . . . . . . .Lt.B.J.Tomlinson,AFRL,Kirtland AFB,NM;and A.Gilbert and J.Bruning,NRC,Albuquerque, NMCryocooler Working MediumInfluenceonOutgassingRate. . . . . . . . . . . . . . .V.F.Getmanets,SR&DB,Kharkov,Ukraine;and G.G.Zhun',Kharkov State PolytechnicUniv.,Kharkov,UkraineAccelerated CryocoolerLife 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 atCryogenicTemperatures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .L.Zhaoand P.E.Phelan,ASU,Tempe,AZ697707717723733743753SpaceCryocooler Applications761Cryocooler Subsystem Integration for the High Resolution DynamicsLimbSounder(HIRDLS)Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D.J.Berry,D.Gutow,J.Richards,and R.Stack,Ball Aerospace&Tech.,Boulder,COEMI Performanceof the AIRS Cooler and Electronics. . . . . . . . . . . . . . . . . . . .D.L.Johnson,S.A.Collins,and R.G.Ross,Jr.,JPL,Pasadena,CAThe Applicationand Integrationof MechanicalCoolers. . . . . . . . . . . . . . . . . . .R.M.Wilkinson,S.R.Scull,MMS,Bristol,England; A.H.Orlowska and T.W.Bradshaw,RAL,Chilton,England;andC.I.Jewell,ESA-ESTEC,Noordwijk,The NetherlandsCoolingSystemforSpaceApplication. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .G.L.Ji andY.Wu,Shanghai Inst.ofTech.Physics,Chinese Acad.ofSci.,Shanghai,ChinaDriveandControlSystemforaStirlingCryocooler. . . . . . . . . . . . . . . . . . . . . .W. Biao,G.Ji,andY.Wu,Shanghai Inst.ofTech.Physics,Chinese Acad.ofSci.,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;andM.J.Griffin,QueenMary&WestfieldCollege,London,UKDesign of a 90 K Cryogenic Passive Cooler for the IASI Instrument. . . . . . . .D.J.Doornink,Fokker Space,Leiden,TheNetherlands761771781787791795805CONTENTS xviiCryocoolersforHumanandRoboticMissions toMars. . . . . . . . . . . . . . . . . . . .P.Kitteland L.J.Salerno,NASAARC,MoffettField,CA;and D.W.Plachta,NASALeRC,Cleveland,OH815CommercialCryocooler Applications823DesignConsiderationsforIndustrial Cryocoolers. . . . . . . . . . . . . . . . . . . . . . . .C.M.Martinand J.L.Martin,Mesoscopic Devices,LLC,Golden,COSurveyof CryocoolersforElectronicApplications(C-SEA). . . . . . . . . . . . . . . .J.L.Bruningand R.Torrison,NRC,Albuquerque,NM;R.Radebaugh,NIST,Boulder,CO;andM.Nisenoff,NRL,Washington,DCConstruction and Tests of a High-Tc SQUID-Based Heart ScannerCooledbySmallStirling Cryocoolers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .837C.J.H.A.Blom,H.J.M.ter Brake,H.J.Holland,A.P.Rijpma,and H.Rogalla,Univ.ofTwente,TheNetherlandsCryocooler Applications for High-Temperature SuperconductorMagnetic Bearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .R.C Niemannand J.R.Hull,ArgonneNatl Lab,Argonne,ILAdvancedCryocoolerCoolingforMRISystems . . . . . . . . . . . . . . . . . . . . . . . . . .R.A.Ackermannand K.G.Herd,GECorp.R&D,Niskayuna,NY;andW.E.Chen,GEMedicalSys.,Florence,SC823829847857Indexes869Proceedings Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Author Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Subject Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .869871873AnOverviewofthePerformanceandMaturityofLongLifeCryocoolersforSpaceApplicationsD. S. GlaisterThe Aerospace CorporationAlbuquerque, NM, USA87119M. Donabedian, D. G. T. CurranTheAerospaceCorporationEl Segundo, CA, USA90245T. DavisThe Air Force Research LabKirtland AFB, NM, USA87119ABSTRACTAsurveyismadewhichidentifiesmorethan30longlifecoolersforspaceapplicationscoveringawidevarietyof thermodynamiccyclesandconfigurationtypes. Thesecoolersrangeincapacitiesfroma few milliwatts toover10Wat temperaturesfrom10K toover120K andincludesingleandmulti-stage designs.Theprimaryobjectivesof thisstudyweretoprovideahardwaresummaryandperformancecomparisonforpotentialspacecryocoolerusersandtoserve as an aid to the Air Force in determining future cryocooler development.Fundingforthesecoolersarebeing providedbytheDepartmentof Defense, NASA,andvarious othergovernmentagenciesintheU.S.andabroadaswellasbyinternalresearchanddevelopment moneysfromanumberof companiesthroughouttheworld.Thestudyidentifiesseveralexisting flightqualifiedcoolersandatleast12programswhicharelikelytoprovideflight qualified unitsfor coolingin therange of 10 to150K beforethe turnof thecentury.Thesurveypresentsanoverviewandstatusofthematurityofthevariouscryocoolersandperformance comparisons are made at 35 K, 60 K, and100 K.Cryocoolers 10, edited by R. G. Ross, Jr.Kluwer Academic/Plenum Publishers,1999 12GOVERNMENTCRYOCOOLERDEVELOPMENT AND TESTPROGRAMSACRONYMSAATSRAFRLAIRSATSRBAeBETSCEBMDOCCECOBECOOLLARDODEMDEOSESAFDSFIRSTGSFCHIRDLSHSTHTSSEIMASIRFPAISAMSISSCJPLLADSLMMSMIPASMMRBCMMSMOPITTMSXMTINICMOSPSCRALSBIRS-LSCRSSMCSMTSSPIRIT IIISSCSSRBSSTISTSTESTMUUARSUCSBUSUAdvancedAlong TrackScanningRadiometerAir Force Research LaboratoryAtmosphericInfraredSounderAlong Track Scanner RadiometerBritish Aerospace Systems, LimitedBrilliantEyes TenKelvinSorptionCryocooler ExperimentBallisticMissile Defense OrganizationCryocooler Control ElectronicsCosmic Background ExplorerCryogenicOn-OrbitLongLife ActiveRefrigerationDepartmentof DefenseEngineering and ManufacturingDevelopmentEarth ObservationSystemEuropean Space AgencyFlight DemonstrationSystemFar InfraredSpace TelescopeGoddardSpaceFlightCenterHigh Resolution DynamicLimb SounderHubble Space TelescopeHigh Temperature Superconductivity Space ExperimentIntegrated Multi-spectral Atmosphere SounderInfrared FocalPlaneAssemblyImproved Stratospheric and Mesospheric SounderImprovedStandardSpacecraftCoolerJet Propulsion LaboratoryLow Altitude Demonstration SystemLockheed Martin Missiles and SpaceMicholson Interferometer for Passive Atmosphere SoundingMulti-Stage Miniature Reverse Brayton CryocoolerMatra Marconi SpaceMeasurement of Pollutionin the TropopauseMid-Course Space ExperimentMulti-spectralThermalImagerNear InfraredCamera andMulti-ObjectSpectrometerProtoflightSpaceCryocoolerRutherford Appleton Laboratories, U.K.Space Based Infrared Surveillance-LowSpace Cryogenic Refrigeration SystemsSpace and Missiles System CenterSpace Missile Tracking SystemSpace Infrared Imaging TelescopeStandardSpacecraftCoolerSingle-Stage Reverse BraytonSmallSatellite TechnologyInitiativeSpace Transportation SystemTropospheric Emission SpectrometerThermo-Mechanical UnitUpper Atmosphere Research SatelliteUniversityof California atSanta BarbaraUtah State UniversityOVERVIEWOFPERFORMANCEOFSPACECRYOCOOLERS3INTRODUCTIONAvarietyoflonglife,mechanicalcryogenicrefrigerators(cryocoolers)forspaceareavailable or under development to provide cooling of infrared sensors and spectrometers,opticalelements,lownoiseamplifiers,superconductivitydevicesandotherscientificinstrumentsforatmosphericmonitoringandastronomy.Theauthorsof thispaperprovidetechnicalsupporttonearlyeveryUnitedStatesDepartmentofDefense(DoD)spacecraftprogrameitherimplementing or potentially implementing cryogenic coolingsystems,as wellas to the Air ForceResearchLaboratory(AFRL)atKirtlandAFB,NM,whichistheDoDcenterforspacecryocoolerandcryogenic technology development.Aspartof thatsupport,theauthorsareresponsibleforassessingtheindustryaswellasroutinelypresentingoverviewsandsummariesof spacecryocoolers.TheAFRLrequested thepreparationof anoverview packageof thestatusand maturity of space cryocoolers.Theintent ofthis packageis to help assess the state ofthe artand provide guidelinesfor futuredevelopment of spacecryocoolers.Thepurpose of this paperistopresent a brief overview ofthecryocooler data package.Itis alsotheintent of theAFRLthatthis cryocooler data package be available to any user or vendor who requests it.Severalcaveatsshouldbementionedconcerningthescope ofthisoverviewpackage.Inrecentyears,thenumberofcryocoolersavailablewithpotentialapplicationtospacehasincreasedsignificantly.Itistheauthorsintenttoincludeeverycryocoolerwhoseprimarypurpose is for space application.However,it is likely that some vendors have been missed andthe package is incomplete.In this regard,theauthorsencourage input from those vendors whowere left off the summaryin this paper.SPACE CRYOCOOLER STATUS AND OVERVIEWAsaresult ofthe largenumberof coolersrepresentingseveraldifferentthermodynamiccyclesaswellasseveraldifferenthybridcombinations,andmanydifferentvendors,timeorspace does not permit including allofthese coolers.Rather, a selected summaryofsome of themoreprominentcoolersandprogramsareprovidedinanattempttoprovidearepresentativesample ofthe total population.Tables1a through1e havebeen prepared toprovide an overview.The coolers are listedbyvendorinalphabeticalordershowingthemodel,coolertype,nominalperformance,powerinputincluding electronicseitherestimatedormeasured,thecurrentmaturitylevel(usingthelegend 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 somecases,multiplemodeldesignations are usedwhen thereisadifferencebetweenthevendorsandsponsorsdesignation.Inthediscussiontofollow,thevariouscoolers aregroupedby thenominal operating temperature rangefor which thecooler isbestsuited.Insomecasesthiswillrequire identifyingaspecificcooler morethanonceif itisbeingusedoverabroadrangeof temperatures.Thefourspecifictemperaturerangesusedtocategorize the coolers are as follows:1) 4-12 K, 2)18-45 K, 3) 50-100 K and 4) over 100 K.Itshould be noted thatnewapplicationswith varying temperaturerequirementsand heatloads will need revised designs to optimize performance.This is necessaryas the listed coolershave beenoptimizedforsingledesign pointssuchas2W@60K butarecapableof providingcoolingcapabilitiesatlowerandhighertemperatures. Severaloftheseapplicationsdemandweight reductions and higher efficiencies for ~100 K optics cooling due to considerations such asstringent gimbal masslimitationswhichalsolimitheatrejectioncapabilities.Theveryhighspecific powers at ~10K temperatures have also restricted the use of coolers in this range.4GOVERNMENT CRYOCOOLER DEVELOPMENTANDTESTPROGRAMSOVERVIEWOFPERFORMANCEOFSPACECRYOCOOLERS56GOVERNMENT CRYOCOOLER DEVELOPMENTANDTESTPROGRAMSOVERVIEW OFPERFORMANCEOFSPACECRYOCOOLERS78GOVERNMENT CRYOCOOLER DEVELOPMENTANDTESTPROGRAMSOVERVIEWOF PERFORMANCEOF SPACE CRYOCOOLERS 9Notes to Table 1.1. TMU=Thermo-mechanicalunitCCE=Cooler control electronics(assumed to be6.0 kgif nototherwisespecified)MaturitylegendCDConceptual designBBBrassboardEDM Engineering developmentmodelQMQualmodelPFProtoflight modelFMFlight modelFPFlight provenCOTSCommercial off the shelf3.4.5.6.7.Environmental tests completeda.b.c.d.e.f.RandomvibrationSine vibrationThermal CycleThermalVacuumEMI/EMCShockg.FlightqualificationsTotal power input(includingCCE)estimatedtobeequalto10 watts+compressorinputpower/0.85whennotspecificallymeasured.At300Kunlessotherwisenoted(usuallymeasuredorassumedtobeatthecoolermountingflange).Derivative of 50-80KMultistagerequirementmodified to single-stage requirementTesting hoursleft blankwhen unknownorminimalAlso,nowthat clearancesealconceptswithflexureandgasbearingsareshowingpromiseforlonglife,attention needs to befocused onimproving performancebyreducingcooler weight andreducingirreversible losses in the cooler.For these reasons,optimization techniques need to beintroduced,suchasthose ofBejan46, tominimizebothtemperatureandpressuredropsinthecooler components such ascriticalcoldendand hot end working fluid heat exchangersas wellasregenerators and recuperators.Inaddition both cooler andpayload/spacecraft systemdesignersneed tooptimizethecooling capabilitiesandload requirementsbyutilizingtemperaturestagingof cooling loads to improve overallsystem efficiency.4-12 K Operating RangeTraditionally, coolinginthisrangehasbeenaccomplishedwiththeuseofsuperfluidliquidheliumdewarssuchasIRAS44andCOBE45attemperaturesnear2Korsolidhydrogencryostats such as the SPIRIT-IIIflown on the MSXSpacecraft for cooling near10 K.There hasbeenanincentivetodevelopcryocoolersforoperationinthis rangebecauseof thedesireforlonger lifewithreducedmassandvolumerelativetodewars.Coolerswith capacityforcontinuouscoolinginthe50to100milliwattrangearejustnowemerging. Thisregionofoperating temperatures is the least mature technology at this point in time.MMS 4K Hybrid J-T/Stirling.This cooler is the culmination ofa development activity startedatRALinthemid-1980s.UnderESAfunding,BAe(priortobeingacquiredbyMMS)developedanengineeringmodel ofa4KcoolerwhichhassincebeenqualifiedforspaceflightbyMMS.The coolerconsists ofa two-stageStirling pre-coolerwhichisintegratedwithaJ-Tcryostattoachievefinalcollectionof liquidheliumtoprovidecoolingatnear4K.Theunitproduces 5 to10 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.MMS10K Multi-StageStirling.This programwasinitiatedbyAFRL/BMDOin early1997withtheobjectivetoquicklyproduceaprotoflightqualitycryocoolerwithatleast45mWofcooling at10 K.Towards this goal ofafast turn around,theprogram leverages off of theMMS20Khardwareandusesessentiallyadoubleset ofthe20Kcompressors (foratotalof4).Through regenerator improvementswith rareearth materials,theprogramnow has thepotentialto achieve up to 75 mWof cooling with a motor power of 2000 W/Wor less. The program is on2.10 GOVERNMENT CRYOCOOLER DEVELOPMENTANDTESTPROGRAMSscheduletocompleteaflightqualitythermo-mechanicalunitbyApril1999.Theintent ofthisprogramisnotonlytoproducea10Kflightcoolerfor customerswhomayneedacryocoolerinthenext 3 years, but also to serveas a pathfinderfor future,more optimized Stirling and PulseTube10 K programs.JPLBETSCE10KPeriodicSorption.TheBrilliantEyesTenKelvinCryocooler Experiment(BETSCE)wasdevelopedunderfundingfromUSAF/BMDO/AFRLtodemonstratethetechnology of a hydride sorption cryocooler for operation near10 K andisdescribedin detailbyBard15andWade16.TheflightdemonstrationunitflownonSTS-77inMayof1996wasaperiodiccoolersupplementedwithaStirlingcryocooler toprovide70Kpre-cooling.Theflightunitprovided100milliwatts ofcooling at10K(on a15minuteper 24hour dutycycle)startingfrom70Kwitha power inputof about200W@290K.Thisprogramwascompletedbutthetechnologyderivedhasbeenexploitedfurtherbyapplicationtocontinuouscoolingcryocoolersin the 20-25KregionbyWade16and Bowman17.Theseapplicationsaredescribedinthenextsection of this reportfor coolers in the18-45K range.A more detailed description of the designand performance of the10 K JT cryostat of the BETSCE program is presented byLongsworth34.BallHybridJ-T/Stirling(Redstone).ThisprogramwasrecentlyinitiatedbyAFRLwiththegoalof pushingthestateof theartanddevelopingaveryefficient(lessthan 1000W/Wmotorpower), lightweight10Kcryocoolerforspace applications (includingdoped Siliconinfrareddetectors).Thedesignutilizesanenhanced35/60KStirlingunit(withsome minorregeneratorimprovements)toprovideprecoolingat15to18K toa J-Tcoolerwhichprovidesatleast100mWof cooling at10K.TheJ-Tcompressor usesa rotaryvanedesignwithsignificant heritagefromterrestrialcommercialapplications,butwhichrequiresdevelopmentforlong lifeapplicationwithadryheliumworkingfluid.Thishybriddesigntakesadvantageof theStirlingefficiencyincoolingtocryogenic temperatures fromambientandtheefficiencyoftherecuperative J-T cycle in cooling as the temperature approaches absolute zero.18-45 K Operating RangeThereareseveralcoolersdesignedprimarilyforoperationnearthelowerendofthistemperaturerangeandseveralthatarebestsuitedforthe35-45Krangebutalsooperateveryefficientlyinthe50-80Krange.Engineeringmodelcoolershavebeenavailableforseveralyearsinthisoperatingtemperaturerangeandflightqualifiedcoolersarebecomingavailable.Qualified control electronics are lagging somewhat behind but are being developed.MMS20KMultistageStirling.TheMMS20Kcooler underdevelopmentisbasedprimarilyonthe2-stagetechnologyachievedatRALunderESAfunding.Theprogramwasinitiatedinearly 1994toprovide20KcoolingcapabilityfortheFIRSTinstrument.Theback-to-backcompressors arederivedfromthe50-80Ktechnologycombinedwitha2-stagedisplacerandproduces approximately120milliwattsat20Kplus400milliwattsat30Kforatotalinputpower of 122W.An extensive flight qualification program was completed in early199728.BALL 30 K Multi-Stage Stirling.This cooler was developed by NASA GSFC and was derivedfromearliercoolersusingRAL/Oxfordtechnology.Thecoolerusesdiaphragmspiralflexuresprings with integral back-to back compressorsand a split expander with balancer.The expanderhasincorporatedafixedregeneratordesignallowingforalightweightdisplacer/pistonandimproved coolingefficiency.Thecoolerhasundergonesuccessfulenvironmentalandperformancetestingconductedat GSFCandispresently under lifetest withapproximately 7000hours ofaccumulatedoperation.BALL35/60KDualTemperatureCooler.ThiscoolerisbeingdevelopedbyAFRLasacandidateforcoolingsensorIRFPAs suchasSBIRSLOW.Itisathree-stageunitwiththeupper stage used as a shield for thelower stages that provide 0.4W @ 35K and 0.6W at 60 K.Thedesignwasderivedfromthe twostageNASA GSFC30Kprogramthatalsousedtheupperstageasa [email protected] providesvery efficientcoolingwitha TMUOVERVIEW OFPERFORMANCEOFSPACECRYOCOOLERS11specificpowerestimatedtobe30W/Wat60Kand80W/Wat35K.Thecoolerwillbedelivered to AFRL for performance and endurance testing.JPL20K ContinuousSorption.JPLiscurrentlydeveloping a 20K continuoussorption cooler(LH2) for the PlanckSurveyor program sponsored jointly by NASA and ESA (EuropeanSpaceAgency).Thesystemutilizeshydridecompressors connectedtoaJ-Tcryostatassemblytoproduceliquidhydrogenoperatingnear20K.Apassiveradiatoroperatingindeepspaceatabout 60Kallowsthesystem toproduce about1.2W ofcooling at 20Kwith around 400W ofinputpower.AnEDMisscheduledtobedeliveredbytheyear2000withtwoflightunitsscheduledtobedeliveredtoESAin2003.ThiscoolerusessimilartechnologydevelopedbyBETSCE and the 25K UCSB Long Duration Balloon Cooler35.Creare35KSingleStageReverseBraytonorMMRBC.ThiscoolerisbeingdevelopedbyAFRLas a candidate for cooling sensorIRFPAs such asSBIRSLOW.NASAGSFC has alsosupportedthistechnologyandiscurrentlyusingcomponents ofthe SSRBandMSRBfortheNICMOSflightcoolerandcirculator.ThetechnologyinvolvescomponentimprovementsovertheSSRBtoimproveefficiencyatlower coolingloadsand temperatures.Theoriginalprogramrequirementswerechangedfromprovidingmulti-stagecooling [email protected]@60 K to a single stage providing1.0 W at 35 Kfor approximately the same100 watts ofpower.Thenewandsmallercomponentsinvolveusingpermanentmagnetsforboththecompressormotor(replacingalessefficientinductionmotor)andcryogenicturboalternatorandtheuseof amore compact recuperator design for theheat exchanger.The turboalternator replaces theSSRBturboexpanderallowingreducedparasiticsandelimination ofbrake flow/cooling.Thiscoolerwillbedelivered toAFRLfor performance and endurance testing.LMMSLADS35KSingleStageStirling.Thiscoolerisaslightmodification ofthe L1710CwhichisbasedonpreviousLucas-builtcoolers.ThecoolerutilizesRAL/Oxfordtechnologysuchaslinearmotorsandspiral-flexurebearing supportstomaintainclearance sealsintheexpander andback-to-back compressors.The modificationshaveincludedimprovedcompressionspaceportingandchangeinpositionsensor design.CurrentpredictionsbasedonL1710Ctestdatawillprovide0.5W@35KforaTMUspecificpowerof138W/W.TwoL1710Cunitshavebeenbuiltbuthavenotbeenlifetested.TheseunitshaveaccumulatedafewthousandhoursinvariouslabtestsandoneLucas-builtcoolerhasaccumulatedover16,000hours.Control electronicshavebeenflightqualifiedtoprovideforcancellationofaxialresidualvibration and temperature stability ofthecold-tip.An LMMScompressor hasalso demonstratedlow lateral vibrations using tangential-arm flexures in limited testing.TRW35KModelPTC-010A-035-IandPTC-020C-035-ISingle StagePulseTubes.Thesecoolersweredeveloped underseparateAFRLprogramsandusepreviouslydevelopedtechnologyunderNASA/DoDcontracts.Theback-to-backcompressorsutilizeflexurebearingsupportsforclearancesealsandlinearmotorcompressordriveasdotheirStirlingcounterpartsand arederivedfromOxford technology.The pulse tubecoolers have beensized todeliver 0.3and 0.85Wat 35K.These coolers are currently at AFRL for performanceand endurance testing.TheseunitswerealsoperformancecharacterizedatJPL.Thelargercapacityunithasaccumulated about5,000 hours while the smaller unit has about 4,000 hours.Controlelectronicshave been developed andflight qualified for the smaller capacity unit.RaytheonSingle Stage Stirling 35 K PSC/SMTS.These TMUs are similar to their SSC/ISSCcounterparts.TheSSCwasdesignedunderanAFRLdevelopment [email protected] underIRADandusedforearly SBIRSLOWlifetestingat60Kwhich accumulated 46,000hoursontwounits.Anotherunitsuccessfullyflewonashuttlemission.ThePSCprogramwasinitiatedinlate 1992buttheSMTSbeganonlytwoyears ago.BothunitshavebenefitedfromnumerousimprovementstoincreasetheTMUefficiency.ThePSCunithasincorporated tangential-armflexurespringsfor12 GOVERNMENT CRYOCOOLER DEVELOPMENT AND TESTPROGRAMSclearancesealsupportintheback-to-backcompressor whichhasrecentlybeendemonstratedatJPLtosubstantiallyreducevibrationsinbothaxialandlateralaxes.ThisAerospaceCorp.tangential-arm designhadpreviouslybeendemonstratedonlyinflexure moduletestsandthosementionedfortheLMMScompressor.Theaxialresidualvibrationswerecanceledbycontrolelectronicsfeed-back techniquesaswithothercontrollersusedontheTRW/Ball/LMMSunits.TheSMTSunitsincorporateaheat-interceptconceptfirstdemonstratedatJPLtosubstantiallyreducecold-fingerparasiticsinStirlingcoolers.ThePSCwillbedeliveredtoAFRLforperformanceandendurancetesting.AnSMTSlifetestunitfortheSBIRSLOWFDSprogramhasaccumulated~9000hours.ControlelectronicsforthePSCareflight-type.TheflightelectronicsfortheSMTScoolersarerad-hardandarebeingflightqualifiedbutarenotstand-alone as they are integrated with other payload functions for FDS.50-100 K Operating RangeThelargestgroupofcoolersareinthisrangewiththemajorityoftheunitsinitiallydesignedto operatein the55to 75K range.This area represents the mostmature technology.Several coolers have been flown since the early1990s primarily to support science experimentsor technologydemonstrations.Simple flightelectronics havebeen tested andflown.However,fullyqualified electronicswithintegratedvibrationcontrolcapabilityhaveonlyjustbegunemerging during thelast few years.These are being integratedintoflight systemswhichwillbelaunched in the near future.Ball58KHIRDLSInstrument.BallbegandevelopmentofStirlingcoolersin1990withpurchase ofalicensetobuildclones ofRAL Oxfordtypecoolers.Beginningin1992,Balldeveloped twolines of single-stage cryocoolers aimed at operation at 60 K.On IRAD,Ballbuilta series of two improved designs maintaining the RAL heritage.The initialdesign achieved1.5Wof cooling at 55K and is currentlyon life test at Ball with >23,000 hours.The second versionof thisunit(SA160)provides2.5Wof coolingat60Kfor116Wtothecompressors.Inparallel,Balldevelopedasingle-stageversion of itsSB230cryocooler.Thiscoolerisa fixedregenerator design capable of lifting1.6Wat60K for 53W tothe compressor.Thiscooler isscheduled to fly on the HIRDLS instrument on the NASA EOS Chem Platform in 2002.BallCOOLLAR65/120KJ-T.Thisprogramhasbeeninexistenceforover5yearsandculminatedinasuccessfulmicro-gravityverificationandcharacterizationaboardtheSpaceShuttleinAugustof1997.Thedesignusesanoillubricatedcompressor toprovidethehighpressureratiofora multi-stageJ-T(with some thermo-electriccooler 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 65K stage.It was thus designed to meet a 65 K load profile with peak loadsof 3.5 W. Thecooler wasalsodesignedwithlongflexiblelinesleading totheJ-Tcold head toenable the remote mounting of the compressor.Creare65KSingleStageReverseBrayton(SSRB).Thiscoolerwasdesignedforlonglifeusinghighspeed,smallturbomachineswithgasbearingsallowingvibrationandwear-freeoperation to provide 5 Wof cooling at 65 K.The cooler consists of small-size precision devices.Thecycleoperateswithcontinuousflowofneongascirculatedbyacompressorthrougharecuperativeheatexchangerandturbineexpander.Additionalcomponentsincludeahighefficiencyinverter/controller,aftercoolerandloadheatexchanger.ThistechnologyhasbeensupportedbybothNASAandAFRL.Thecoolerhasachieveditshighestefficiency withasystem (cooler and electronics) specific power of 37 W/W for 7.5watts of cooling @ 65K and aheat rejectiontemperature of280K.ThecooleriscontinuingendurancetestingatAFRLandhas accumulated ~25,000 hours.OVERVIEWOFPERFORMANCEOFSPACECRYOCOOLERS13Creare 65 K Stirling Diaphragm Cooler (SSC).In the late1980s both the USAF andBMDOrecognizedtheneedforalonglifecryocoolercapableof handlingsmallloadsinthe50-80Ktemperaturerange.As part of the generalstandardspacecraft cooler (SSC) program,Crearewasfunded todevelop analternative technologyto theflexure spring cryocoolers being developedbyseveralsources.Aspartofthiseffort,Crearedevelopedanengineeringmodelofacoolerdesignedtoprovide2Wof coolingat 65TheEDMwasdeliveredtotheAFRLinearly1994andhasaccumulatedover10,000hoursof endurancetestingafteritsperformancewascharacterized and documented.The program has been completed.Creare70KNICMOS(SSRB).TheNear-InfraredCameraandMulti-ObjectSpectrometer(NICMOS)isasecondgenerationHubbleSpaceTelescope(HST)scienceinstrumentwhosedetectorsare cooled toabout58Kbya solid Nitrogen cryostat.An anomalydiscoveredinlate1997indicatedthattheoperatinglifeofthedewarwouldreducetheexpectedlifefrom48months to about1.7years.Asa resulttheNASAGoddardSpaceflight center (GSFC)decidedtoattempt to retrofit thesolidcryostatwithanimprovedversion of theCreare5WSSRB.Thenew cryocoolerisdesigned toprovideapproximately7.7Wat70Kfora totalinputpowerofaround315W.The newsystem alongwith a newly developed flight electronics package istobeflighttestedaboardtheSTSinlate1998withfinalintegrationinto theHST in early2000.LMMS1710-C/SCRSStirling.Since1987Lockheed-Martinhasbeendevelopingadvancedcryocooler systems basedon theOxfordtechnologyunder a teamingarrangement withLucasAerospace (sinceterminated). Severaldifferentmodelsemergedfromthisactivityincludingthe1710-CandSCRSdiscussedinthisparagraphandtheLADSunitwhichwaspreviouslydiscussed.The1710-Cconsistsof back-to-backcompressorsconnectedtoasingledisplacer,providingabout2.0Wat60Kwithatotalpowerinputof130Wincludingthecontrolelectronics package whichhas been flight qualified.Utilizingsimilarhardwarewithaslightlylargercompressorpistondiameter,anintegratedsystemwasdevelopedastheSCRS, funded jointlybyseveralUSAForganizationsaspart oftheSPAS-IIIflightexperiment.Twocompressorsandtwodisplacers whichhavetheircoldtipattachedviaflexcouplingsinacommonvacuumhousingprovidedabout1.2Wofcooling at 59 K. This assemblywas tested and delivered to the Utah State University foroverallsystem testing.Raytheon Stirling 60 K PSC/SMTS/ISSC/SSC.Asstated for the Raytheon Stirling35K units,these coolers have a common TMU heritage(e.g.,expander/compressor sizing)in that they wereoriginallydesigned for cooling2W@60/65K.Both the PSCand SMTScoolersarethesameunitsfor35and60Kapplication.TheSMTSunithasalowercoolingrequirementfor60Koperation of the same order as the 35K requirement.TheSMTS life test cooler has been operatedat60Kaswellasat35Kmentionedaboveaspartof the~9000hoursof operation.AlsoasmentionedaboveoneISSChasaccumulatednearly24,000hourswhiletheotherlifetestunitaccumulated 22,000 hours.The respective TMUspecific powers for the ISSC andSSC units @65K are 45W/W for1.75and 1.2 watts.The respective TMUspecific powers for the PSCandSMTS(with heatintercept)are27.5and22.4W/Wat60K.WithoutheatintercepttheSMTSTMUspecific power isabout the same asthePSCTMU which doesnot use theheatintercept,i.e.,27.5W/W.TheISSC#4wasmodifiedtoimprovemotor efficiencyandthermalinterfaces.It was also tested under higher charge pressure and achieved improved performance.TRW60KPTCModelsfor AIRS,TES,6020,andIMASPrograms.Thesecoolersinbothintegral(I)andsplit(S)configurationshavebeendevelopedforbothNASAandAirForceprograms.TheyhavecommonheritagetotheabovementionedTRW35Kcoolers.Twoflightmodels of the PTC-010B-055-S (55K) have been delivered to the NASA AIRS program and twoflightunits of thePTC-010C-057-I(57K)willbedeliveredtoJPLin1999for TES.PTC-010A-060-I(60K)willbedeliveredasaflightunittoMTIin1998.AnEDMofthisunitwasdeliveredtoAFRLforenduranceandperformancetestingafter beingperformancecharacterized14GOVERNMENTCRYOCOOLERDEVELOPMENTANDTESTPROGRAMSatJPL.PTC-004A-055-IwillbedeliveredtoJPLin6/98astwoEDMunitsfortheIMASprogram.TRW60-150KIntegralMiniatureStirling(SC-0-6A-65-I)andIntegralMiniature PulseTube(PTC-001A-115-I).These coolerswere developedfor DODrequirements and havebeendeliveredfor severalapplications includinglifetesting and opticscooling forSBIRSLOW.Twomini-Stirlingcoolerswerelifetestedfor~15,000hourseachtoprovide0.16W@60KforaninitialSBIRSLOWIRFPArequirement.ThecorrespondingTMUspecificpowerat60Kis88W/W.AtthesametimeTRW ranlifetestsontwoIRADcoolersfor thesameprogram,oneofwhich has accumulated ~27,000 hours to date.The Stirling cooler will be a part of theHTSSE-IIpayloadtobelaunchedontheARGOSspacecraftinDecember1998.TwominiatureP-Tsare currently operating on the CX payload and have accumulated 3 months of operation.MMS50-80KStirling.Thiscoolerisamodificationof thesingle stage80KcoolerformerlyknownastheBAe80K.The80KcoolerwasbuiltandqualifiedforanESAcontractunderalicensingagreementfromOxfordUniversitywheretheoriginaldevelopmentalworkwasperformed.The heritage ofthisdesignisbasedon two singlestagecoolersdeveloped byOxfordandRALwhichwereflownaspartof theImprovedStratosphericandMesosphericSounder(ISAMS)instrumentaboardtheUpper AtmosphereResearchSatellite(UARS)inSeptemberof1991.Thesecoolersaccumulated wellinexcessof25,000hoursinorbit. Severalgroundtestunitshaveaccumulated over50,000hourseach.Also,RALhasbuilttwosimilar singlestagecoolersbasedonthesameRAL/Oxfordpressuremodulatortechnologythatwasflownsuccessfully for up to7 yearsin the1970s before the instruments (Pioneer Venus, Nimbus 6and7)wereturnedoff.Thefirstunitflewaspart of theAlongTrackScanningRadiometer(ATSR)instrumentaboardtheEarth Resources Satellite(ERS-1)inJuly1991andwasfundedbyESA.Thesecondunit flew on ATSR-2which replaced ATSR-1.The totalflight hoursfor both RALcoolers have exceeded 60,000 hours.Thebasic50-80Kunitwhichisalso flightqualifiedhasbeenmadeinbatchesof15andasofthis writingover45unitshavebeenmanufactured.Anumberof programssponsoredbybothNASAandESAarescheduledtoflythisunitoverthenextseveralyearsincludingMicholsonInterferometer for Passive AtmosphereSounding (MIPAS )and the Measurement forPollutionintheTropopause(MOPITT)instruments.Thenominalperformanceof thisunitisusuallyquotedas1.7Wat80Kbutitisbeingusedoverawiderange oftemperaturesfromabout58K to90 K.Details of the acceptance and qualification programs aredefinedby Jones43andDavies27.Individual life test units have accumulated over 20,000 hours.Above 100 KAlthough virtually all ofthe coolers in the previous two ranges can beoperatedat muchhighertemperatures,theperformance oftheTRWMiniatureP-T(MPT)andminiatureStirling(MSC)unitshavebeencharacterizedattemperaturesupto150Kspecificallytobecompatiblewithcooling optics,shields, etc.TheMPT cooler TMUspecificpower for1.5W@115Kis~13.4 W/W. for 2.5W @150 K is8.2W/W, and for1.25W @175K is 5.8W/W.TheMSCTMUspecificpowerfor [email protected]/W,[email protected]/W,andfor1.3W@150 K is 6.4W/W.However the Raytheon PSC/ISSC, TRW PTCs,LMMS,BallandCrearecoolershavebeenproposedandinsomecasestestedforoperationatthe100to120Klevel.Forgimbaledopticswithlimitedheatrejectioncapabilities,projectedrequirementsarecoolingloads of6 to10 watts at ~100K with TMUspecific powers aslow as8 to10W/W andlightweight unitsof 3to5kg.Current performance ofthe RaytheonPSCandTRWPTsareinthe12to14W/Wrangeatthistemperaturewithmassesover12kg.Allof theabovecoolerswouldrequirere-designtomeetthese100Kcoolingandmassrequirements.Because ofthisdeficiency,theAFRLhasinitiatedtheHighEfficiencyprogramtodeveloptechnologytomeetthefuturegimbaled opticsrequirements.OVERVIEWOF PERFORMANCE OF SPACE CRYOCOOLERS15SPACE CRYOCOOLER PERFORMANCE COMPARISONMethods and CriteriaThecryocoolercapacity,power efficiency,andmassefficiencydataarepresentedhereatreferencetemperatures of 35,60,and100K.Thedatawascompiledfromnumerousvendorandgovernmentsources1-46.Thedatawasinterpolatedornormalizedtoareferencecoolingloadtemperature and a 300 K rejection temperature using the following Carnot cycle ratio:wheretheQisthecoolingcapacityandTisthetemperatureeitheratthecoldtip(ct)orheatrejection(rej)interface.Theuseof thisratioassumesthattheCarnot efficiency(orrefrigeratorcoefficientof performance)is thesamefor boththedataandreferenceconditions.Theequationcalculatesthecoolingcapacityatthereferenceconditionsforthesameinputpowerasthedata.TheCarnotratiowasalsousedtointerpolatetheuppertemperaturecoolingloadsofafewmultistage cryocoolers to allow a (very) rough comparison to singlestage units.Therearemanycaveatstothedatabase.TheerrorassociatedwiththeCarnotextrapolationincreasesasthedataconditionsdeviatefromthereference.Forcoolingloadtemperaturedifferencesgreaterthanabout5Korrejectiondifferencesgreaterthanabout20K,theCarnotinterpolationissuspect.Also,becausethedatabaseforflightqualitycryocoolerelectronicscontrollersislimited,theinputpowerfromtheelectricalbusformostofthedatahasbeenestimatedfromthemeasured motorpower.Agenericelectronicsestimate of6 kgwith85%efficiencyand10Wof quiescentpowerwasusedforcryocoolers whichdonotcurrentlyhaveflightlikeorflightqualityelectronics.Theestimateofelectronicpowercaneasilyresultininaccuracies of 5%. Overall, the database is to be used onlyfor approximate ( 10-20% at best)comparisons betweencryocoolers.Also,thereferencecoolingloadtemperatureisatthecryocoolercoldblockinterface,whichcanbesignificantly(typically5Kfor1to2Wloads) colderthanthecooledinstrument.Forcryocoolersorapplicationswhere thecoolercoldheadcanbedirectly(withoutathermalstrap)mountedtotheinstrumentinterface,thistemperaturegradientcanbesignificantlyreduced.Becauseoftheirlongflexiblelinesfromtheircompressorstothecoldhead,theJoule-ThomsonandBraytoncyclecryocoolerscanmoreeasilybemounteddirectlytotheinstrumentinterface.Thus,theJoule-ThomsonandBraytoncryocoolershavethepotentialtoberunathigher(about3-5Kfor1-2Wloads)coldtiptemperatures (and, thus,decreased inputpowerandincreasedefficiency) while still maintaining the same instrument temperature.Sincethereareonlyafewexistingflightelectronichardware units,arelativeevaluationofthecryocoolermotorpowersisoftenmoreaccuratethancomparingthetotalinputpower.Themotorpowermaybemisleadingforunitsorcycleswhichhavesignificantlydifferentelectronicpowerrequirements.TherelativeefficiencyoftheBraytoncryocoolerimprovesusingtotalpowercomparedtousingonlymotorpowerbecauseoflesspowerconsumptionintheelectronics.Cryocooler Mass and Power Performance at 35, 60, and100 KFigures1and 2 are plots ofcryocoolermotor specific (input dividedby cooling capacity)andtotal(motorandelectronics)power, respectively,forcoolingat60Kasafunctionofcooling16 GOVERNMENT CRYOCOOLER DEVELOPMENTANDTESTPROGRAMSFigure1.Cryocooler motor specificpowerFigure 2.Cryocooler totalspecificpowerinterpolated to 60Kcooling and 300Kreject.interpolatedto60K cooling and300K reject.Figure 3.Cryocooler totalspecificmassFigure 4.Cryocooler motor specific powerinterpolated to 60 K cooling and 300Kreject.interpolatedto 35K cooling and300Kreject.Figure5.Cryocooler total specific powerFigure 6.Cryocooler totalspecificmassinterpolated to 35K cooling and 300 K reject. interpolated to 35K cooling and 300 K reject.OVERVIEWOFPERFORMANCEOFSPACECRYOCOOLERS17Figure 7.Cryocooler motor specificpowerFigure 8.Cryocooler totalspecific powerinterpolated to100 K cooling and 300K reject.interpolated to100 K cooling and 300 K reject.Figure 9.Cryocooler totalspecificmassinterpolated to100 K cooling and 300 K reject.capacity.TheFiguresshow theexpected effect of efficiencyincreasingasthecapacityincreasesand indicate thegeneraltrendat 60K ofthe higher efficiencyatlow to mediumloads ofStirling(especially the Raytheon PSC) and Pulse Tube cryocoolers compared with the Reverse Brayton.Figure3is a plot of cryocooler specific mass (SMor mass divided bycoolingcapacity)forthe totalunit (including electronics)for cooling at 60Kasa function of coolingcapacity.Thetrend ofincreasedmass efficiency withincreased capacityis indicated.Thelight weight natureof the Brayton cryocoolers and the TRW IMAS design is also apparent.Figures4to6and7to9aresimilarplotsof thespecificpowerandmassasafunctionofcooling capacityfor coolingat35Kand100K,respectively.Of significanceat35Kisthepotential(basedonlyoncomponenttests)improvedrelativeperformanceoftherecuperativeBraytoncycleCreareMMRBCatlowertemperatures.At100K,if successful,thenewstartAFRL High Efficiency program with goals of less than 10 W/W motor power and less than 1kg/W total mass for10 Wof cooling should make significant advances over the state of the art.SUMMARYAnoverviewispresentedofthestatusandperformanceforawiderangeoflonglifecryocoolers being developed for space applications ranging in temperature from10K to atleast100K.Thissurvey identifies more than30 coolers coveringa varietyof thermodynamiccyclesandcoolertypeswithcapacitiesfromafewmilliwattstoover10Wandincludessingleandmulti-stage designs.Thesurveyindicatesthatmorethanadozencoolersareatornearflightmodelstatusandare undergoing flight qualification tobeavailablefor spaceapplicationsbeforethe turn of the century.Performancecomparisons were made using plots of specific power and18 GOVERNMENT CRYOCOOLER DEVELOPMENTANDTESTPROGRAMSspecificmassasafunction ofcapacityattemperatures of35,60,and100K.Thecomparisonsshow therelatively higher efficiencies ofStirling andPulse Tubecyclesnear 60K,the increasedefficiency of allunits with increasing capacity, and the potentialincrease in both power and massefficiency for thenew startAFRLHighEfficiencyprogram.ACKNOWLEDGMENTThe authors wish to acknowledge the support of personnel at the Air Force Research Lab andtheBallisticMissileDefenseOrganization.Special thanks aregiventoJ.P.Reilly andLt.B.J.Tomlinson ofAFRL,S.Bard,B.Bowman, R.Ross,Jr.,andL.WadeoftheJetPropulsionLab,R.Fernandez,W.Gully,W.Kiehl,R.Levenduski,andR.Reinkerof Ball,W.Swift ofCreare,D.Gilman and K.Price ofRaytheon, T.Nast andI.Spradley of LockheedMartin, B.G.Jones ofMatra Marconi Space, and C. 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G. Ross, Jr., Ed., Plenum Press, New York (1995), pp.55-67.42.Spradley,I.E.andW.G.Foster,SpaceCryogenicRefrigeratorSystem(SCRS)ThermalPerformance Test Results, Cryocoolers 8, R. G. Ross, Jr., Ed., Plenum Press, New York (1995), pp.13-22.43.Jones,B.G.,etal.,TheBatchManufacturingofStirlingCycleCoolersforSpaceApplicationsIncludingTestQualificationandIntegrationIssues,Cryocoolers9,R.G.Ross,Jr.,Ed.,PlenumPress, New York (1997), pp. 59-68.44.Petree,D.andP.V.Mason,InfraredAstronomicalSatellite(IRAS)SuperfluidHeliumTankTemperature Control, Adv. Cryo Engr, V. 29 (1983), pp. 661-667.45.Volz,S.M.,etal.,CryogenicOn-OrbitPerformance ofthe NASACosmicBackground Explorer(COBE), SPIE Conference, San Diego,California (July1990).46. Bejan, A., Entropy Generation Minimization, CRC Press, New York (1996).AirForceResearchLaboratoryCryocooler TechnologyDevelopmentThomas M. Davis,John Reilly,and First Lt. B. J. Tomlinson, USAFAir Force Research LaboratoryKirtland AFB, NM 87117-5776ABSTRACTThispaperpresentsanoverviewof thecryogenicrefrigeratorandcryogenicintegrationprogramsindevelopmentandcharacterizationundertheCryogenic 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-tioningspacecryogenicthermalmanagementtechnologies.TheprimarycustomersfortheAFRLcryogenictechnologydevelopmentprogramsareBallisticMissileDefenseOrganization(BMDO),theAirForceSpaceBasedInfrared System(SBIRS)Lowprogramoffice,andotherDoD space surveillance programs.Thispaper willdescribetherangeofStirling, pulse tube,reverseBrayton,Joule-Thomsoncyclecryocoolers,andsorptioncryocoolerscurrentlyunderdevelopmenttomeetcurrentandfutureAir ForceandDoDrequirements.TheAFRLcustomersingle stagecoolingrequirementsat10 K,35K,60 K,150 K,and multi-stage cooling requirements at 35/60 K are addressed.Inordertomeetthese various requirements,theAFRL Cryogenic TechnologyGroupispursuingvarious strategic cryocooler and cryogenic integration options.TheAir ForceResearchLaboratoryisalsodevelopingseveraladvancedcryogenic integra-tion technologiesthat willresultin thereductionin current cryogenicsystemintegration penal-tiesanddesigntime.Thesetechnologiesincludethecontinueddevelopmentof theCryogenicSystems Integration Model (CSIM), 60 K and100 K thermal storage units and heat pipes,cryo-genicstraps,thermalswitches,anddevelopmentofanIntegratedLightweightCryogenicBus(CRYOBUS).INTRODUCTIONThe use of long-life, active cryocoolers provides a significant improvement to DoD spacesurveillance and missile tracking missions.Cooling of infrared sensorsin space at temperaturesof80Kandbelowhasmainlybeenaccomplishedusing storedcryogens.Theseexpendablecryogenic systems require thelaunch of heavy and complexdewars,which at best have a one ortwoyearlife.Cooleddetectorsallow vastimprovementsinidentificationanddiscriminationCryocoolers10,edited by R.G.Ross, Jr.Kluwer Academic/Plenum Publishers, 1999 2122 GOVERNMENT CRYOCOOLERDEVELOPMENTAND TEST PROGRAMScapabilitywithaminimumofsensorapecturegrowth.Smallerapectureproducescheaper,lighter sensors; much easier to host in a space-based environment.Other space missions such ascommunications,remote sensing,andweathermonitoringcanbenefitfromsubsystemsusingcryogenictechnologyincludingsuperconductingelectronics,highdataratesignalprocessors,and highspeed/low power analog to digital converters.TheobjectiveoftheAirForceResearchLaboratorycryocoolereffortistodevelopanddemonstratespacequalifiablecryogenictechnologiesrequiredtomeetfuturerequirementsforAir Force and Department of Defense (DoD) missions. Pursuant of this objective, the Air ForceResearchLaboratorycharacterizesandevaluatestheperformanceofdevelopmenthardware,pursueadvancedconceptsforfuturespacecraftmissions,andworktoenhancecryocoolertospacecraftintegration.CryocoolerdevelopmentisconsideredaMilitaryCriticalTechnologyandisalso tracked under the Defense TechnologyObjectivesinitiative.Performanceimprove-ment objectives have been established for life, power, mass,and vibration.Progress is reviewedannuallyat DoDlevel. Collaboration withother government developmentactivitiesand privateindustryhasbeenamajorstrengthoftheAFRLprogram.Thishasresultedinleveragingofscarcedevelopment fundingandmorerapidtransitionofcryocoolertechnologytothespacecommunity.CurrentAFRLcryocoolerdevelopment programsinclude Stirling,pulsetube,reverseBrayton,Joule-Thomson,andsorptionmachinesthat producecoolinginthe10Kthrough150K temperature range. Compared with state-of-the-art dewars and cryogenic radiators, mechani-calcryocoolersofferspacesystemssignificantweightsavings,performanceimprovements,andlong life potential (greater than5years).Afteraspecificcryocoolerisdeveloped,theunitissubjectedtoacceptance,characteriza-tion,and endurance tests based oncustomer and Air Forcerequirements.Acceptancetestsareperformed to determineif the unitmeetscontractual specifications. Characterizationisthenper-formedtodeterminetheoperatingperformance envelope ofthe cryocoolerinnominalandoffnominalconditions.Endurance tests are used to demonstrate operationalhours,and identify andcharacterize long term, life limiting failure mechanisms and long term performance degradation.Componentsthat significantlyimprovethe efficiency,extendlife,reduce mass,or limitin-ducedvibrationaredevelopedandtransitionedintonextgenerationcryocoolerdesigns.Thesetechnologiesaretypicallydevelopedunder contractorsponsoredIn-houseResearchandDevel-opment (IRAD) effortsor from the SmallBusiness Innovative Research (SBIR) program.Advanced,highpay-off cryogenicintegrationtechnologiesaredevelopedthatreducerisk,complexity,mass,andvolumeofthecryogenicsystem.Utilizationofimprovedintegrationtechnologies ensuresan optimum cryogenic thermalmanagement system is developed that limitor eliminatesoperational constraintsimposed onthe spacecraft platform.Thewarfighterpayoffsfortheseinnovationsenablelong-life,spacebasedsurveillancetosupport tacticalandstrategic missions. Additionally,cryocooler technologyhasbeenidentifiedas enabling technology for national missile defense systems.CRYOGENIC TECHNOLOGY DEVELOPMENT REQUIREMENTSSpacecraft cryocoolerrequirementsdifferquitedramaticallyfromtactical cryocoolerappli-cationsduetotheimpositionofarequirementforlonglifeandcontinuousoperation. Opera-tionallifetimesforstrategic spacecraftareusuallyinthe5-10yearrange.WithmostAirForcespacecraft operatinginorbitsthatprecludeperiodicmaintenance,utilizationofhighly reliablecomponentsis critical.Current Air Forceoperational requirementsresultinthe need forsingleandmulti-stagecoolingforshort,mediumandlongwavelengthinfraredsensors.Insomein-stances, DoDspacecraft are limited in terms of allowable payload power,mass,or volume.Thisresultsinanadditionalrequirementforhighlyefficientthermodynamicmachinesrequiringminimalinputpower,lightweight structure,andpackagedforassmallavolumeaspossible.Additionalconstraintssuchasvibrationsuppressionor minimizationarerequiredtomitigateoreliminateinducedvibrationfromaffectingsensor operation.AFRLCRYOCOOLERTECHNOLOGYDEVELOPMENT23Inordertomeetcustomerrequirements, cryocoolerdevelopmenthasexploreddifferentthermodynamiccyclesandvariationsof thermodynamiccyclesinorder todevelopa baseofcryocoolers for specific and generalapplications. Each thermodynamic cycle or variation has itsowninherentstrengthsandweaknesses.Additionally,thematurityof thetechnologyforthesecyclesvaries.Thebottom lineisthatdifferingcustomerrequirementsdictatedifferentthermo-dynamic cooling cycles to satisfy mission requirements. The following section,Cryocooler De-velopmentPrograms,willhighlightthedifferentthermodynamic cyclesandthedevelopmentprograms pursuing the different technology options.Therequirementsforcryogenicintegrationdrivethedevelopmentof componentsthatim-prove the cryogenicsystem by reducing largesystem penaltiesandanalysis errors.Thesetech-nologiesinclude thermalstraps,thermalstorageunitsforloadleveling,thermalswitches,cryo-geniccapillarypumpedloops,diodeheatpipes,thermaltransportdevices,thermalinterfacetechnologies,and thermal analysis tools.Thesourcesof thetechnicalrequirementsareUSAF,BMDO, and DoD needs.Typicalcryocoolerprogramsincludethedevelopmentof flightqualityelectronics.Recentexperience by AFRL and other agencies in the development of flight electronics have resulted ininflexible,ineffective,expensive,and outdated designs.Inordertoachievea lowcostandef-fective solutiontothisproblem for users, AFRL hasinitiatedanin-houseefforttodevelopanapproach for a common flight electronics design potentially applicable for use with Stirling andpulse tube cryocoolers.AFRL has assembled an in-house team to review the multiple technicalissuesand developa common designfor vibration control,temperature control,and cryocoolerhealth monitoring. The initial phase ofthis effort is to demonstrate the feasibility of this conceptbydevelopingandevaluating breadboardhardware.PhaseIofthiseffortwascompletedinMarch1997and the final report is now being finalized.PhaseIIwill focus on identifying indus-try requirements and the development of brassboard hardware for a proof of concept demonstra-tion.The planned completion date planned for this effort isAugust1998.Thetechnologyissuesinvolvedincoolingof thegimbaledopticsfortheengineeringandmanufacturing design (EMD) phase of the SBIRS Low system is a high priority for both BMDOand theSBIRSLow program office.AFRL isinvestigating cryogenic solutionstothe twoaxisgimbal problems to provide technology solutions tominimize the combination of system penal-ties for mass, volume, power, and flexibility to meet identified mission goals and requirements.CRYOCOOLER DEVELOPMENT PROGRAMSAFRL cryocooler developmentincludesvarioustypesof activecoolingcryocoolers.Inthefollowing sections,Stirling (also pulse tube) cycle,reverse Brayton cycle,Joule-Thomson,andsorption cryocooler development programs at AFRL are detailed.Stirling Cycle CryocoolersBackground The Stirling cycle cryocooler is the most mature design of the cryocoolers de-veloped for theAir ForceResearchLaboratory.ThesedevicesoperateundertheStirlingther-modynamiccyclewithamechanical compressorandexpandercombinedwitharegenerator.The advantages inherent in this type of cooler are lowest combined volume and mass, less com-pressorsweptvolumethanpulsetubes,andthemostpowerefficientcryocooling.Theinputpower for this type of cooler is typicallyless than other coolers for temperatures greater than 20K or loadslessthan5W.Someof the disadvantagesfor thiscooler are thesub-mil ()clearanceseals,concernwiththecrossaxisvibration,andconcernswiththereliabilityofthemovingexpander/regenerator.Raytheon (formerlyHughesAircraftCompany) PSCCryocooler The60KProtoflightSpace-craft Cryocooler (PSC)is under development byHughesand funded byBMDOandSBIRSLow(Figure1).Thisdesignis the maturest ina series ofcryocoolers developed by USgovernmentand US company sponsored IRAD resources.Specific objectives ofthisprogram are to develop24GOVERNMENT CRYOCOOLER DEVELOPMENT ANDTESTPROGRAMSa unitrequiringlessthan100 Watts ofinput power with2Wattsof cooling,lifeinexcessof7years, and totalsystem mass less than 33kg.The design ofthis cooler has the potentialtomeetthe requirements for the MWIR and LWIR tracking sensor needs for the SBIRS Low EMD sys-tem.Designfeatures include incorporationofalineartangentialflexureintothecompressor.This innovation allows for improvement in radialstiffness and is expected to result in improvedcryocoolerreliabilityandperformance.Titaniumhasbeenutilizedwithinthehousingandpis-tonassemblytoincreaseunitefficiencyandresultinreducedsystemmass.Hugheswillalsodemonstratetheadequacy ofpistonalignment techniques necessary for ensuring adequatesub-milclearanceof moving parts.Thefirst protoflight unitwasdeliveredinDecember1997,andsubsequently subjected to acceptance characterization tests and endurance evaluation at JPL andthe Air Force Research Laboratory.Ball AerospaceCryocooler AFRL isdevelopinga multi-stageStirling cryocooler withBallAerospace.The objective of this effort is to simultaneously provide 0.4 Watt ofcoolingat 35Kand 0.6 Watt of cooling at 60 K.The Ball 35/60 K program is a candidate to meet BoeingsLow Altitude Demonstration System ground demonstration tracking sensor imager requirementsfor simultaneous cooling at 35K and 60 K (Figures 2 and 3).In addition, the cooler is a tech-nologyoptionfortheSBIRSLowEMDtrackingsensor.Asaresult,thecryocoolermustbeable to achieve 0.1Nrms vibration requirement and a greater than 7 year lifetime.The Ball ef-fortisa BMDO/Air Forcefundedprogrammanagedby NASA/GSFC.TheAir Forceprogramis building upon technology previously developed for a NASA 30K two-stage cryocooler3.BallismodifyingtheNASAcompressordesigninordertohelpdoublethecoolingcapacity.Tosatisfy requirements, the displacer was redesigned from a twostage to a three-stage design.Thecoldfinger featuresa fixedregenerator,whichimproveslife,efficiency,andreducesinducedvi-bration.Additionalperformance improvement isrealized by theincorporationof precision pis-tonalignment techniquesthat eliminate piston/cylinder contact inthecryocooler.Aprotoflightcryocoolerwithassociatedflight electronicsisplannedfora deliverytotheAir ForceResearchLaboratory in March 1998 where it willundergo characterizationand endurance evaluation.Figure 1.Hughes 60K Protoflight Spacecraft Cryocooler.Figure 2. Ball Three-Stage Cryocooler.Figure 3. Ball Three-Stage Electronics.AFRL CRYOCOOLER TECHNOLOGY DEVELOPMENT25Figure 4. MMS 20 K Cryocooler.Figure 5. Defense Research Agency Cryocooler.Matra MarconiSpace(MMS)Cryocooler SponsoredbyBMDO,thisprogramisintendedtomeetnear-termrequirementsfor10KVeryLongWaveInfrared(VLWIR)sensortechnology.The cooler under development is designed to meet a requirement of 45 mW@10 K. The designwill utilize four of MMSs standard compressors for their 20 K cryocooler with a multistage ex-pander.The MMS20 K cryocooler canbeseeninFigure 4.The primary technology challengeis to identify regenerator materials capable of achieving the required cooling at 10 K.Simula-tion,modeling,andtestingofpotentialregeneratordesignswerecompletedatRutherfordAppletonLaboratory inFebruary1998.The engineeringdesignmodelcryocoolerisscheduledfor delivery to AFRL in May 1999.DefenseResearchAgency(DRA)CryocoolerDRA,underBMDOsponsorshipandAFRLtechnicalmanagement,hasdevelopedanddeliveredacryocoolerdesignedtomeettheSTRVmission requirements of 0.25 W@65 K. Figure 5 shows the DRA cryocooler without the com-pressor cover.Twoversions ofthecryocooler weremanufactured.One version hasa linear flexurespringdesign and the other version has a flexure leaf design. Both units have contacting, wearing sealsand are predicted to have lifetimes on the order of 20,000 hours.PULSE TUBE CRYOCOOLERSBackground ThepulsetubecryocoolerisaStirlingthermodynamic cycle.However,thisdesign approach has a compressor, regenerator, a passive pulse tube, and orifice to a gas reser-voir.TheStirling expander hasbeenreplaced by a combinationof the passivepulsetubeandorificetoreservoir.Theadvantagesassociatedwiththisapproacharenocryogenicsub-milclearanceseals;higherreliabilityduetoreducednumber of movingparts,andreducedelectro-magnetic interference and vibrationat the cold block. A disadvantage to this design isa slightlylower Carnot efficiency than the Stirlingcooler (due totheirreversibilitiesin the pulse tube ex-pansion) and integration difficulties due to the configuration of the cooler and the location of thecold block.TRW 35K PulseTubeCryocoolerProgram AFRL,BMDO,andSBIRSLowprogramofficesponsored thedevelopment of severalsingle-stage pulse tube cryocoolersunder the35K PulseTube contract with TRW. The goal of this effort was to improve pulse tube performance and re-liability to match the maturity of Stirling cryocoolers. TRW delivered three engineering modelsunder thiseffort(twounitsdesignedfor35Kandoneunitdesignedfor60K);allbuiltaspro-toflight units4.The35K Pulse Tube programalso focused onminimizingweight(7yearslife.TheAFRLcharacterization facilityandAerospaceCorporationarealsoplayingacriticalroleinimproving reliability confidenceofcryocoolers.Leveraging existing capabilities at JPL, GSFC, other government laboratories, andprivateindustry,theAFRLfacilitysupportsperformanceverificationandreliability evaluationof developedhardwareina simulatedoperationalenvironment.Theprincipalfocusof thefacil-ity is to improve reliability confidence in cryocooler hardware and provide better understand oflife-limitingfactors.The end result ofthisprocessistoinfluenceimprovementsindesignsandreliabilityof future cryogenicsystems.Cryocoolercharacterizationandendurance testingisbeingaccomplishedontheCreareTurbo,TRWpulsetubes,andHughesSSCunits.BoththeHughes60K PSCandBallAero-space 35/60 K will begina three-year endurance test simulating space operational conditionsinearly1998.Severalactionshavebeentakentomakethefacilitymorerelevantandresponsivetouserneeds.Amajoreffortisbeingmadetoimprovethefeedbackof evaluationdatatothespacecommunity.Anear-termsolutionrecentlyimplementedwastoincorporateloadlinedata into the Aerospace Corporationdeveloped CSIM.Users of this modelwillnow havenearrealtime information fromAFRLperformance evaluations.Makingcryocoolertestdataandother relevant information available on the AFRL Web page isalso being evaluated.Test planshave expanded to include a broader range of temperature ranges during performance evaluation.AFRLrecentlyestablishedaworkinggrouptomoreformally addresstherangeof cryo-cooler reliability issues.The groups charter is to identify and implement actions to improve re-liability confidenceofspacecraftcoolers.AcollaborativeeffortwiththeUkrainian InstituteofLowTemperaturePhysicsisassessingthepossibilityofapplying acceleratedlifetime testingmethodology to selected AFRL cryocoolers.Aerospace Corporation hasmade significant prog-ress in critical component reliability throughthe development of flexure bearingsto satisfy lowtolerance cryocooler design requirements.The Aerospace developed tangential spring has beenbaselined in the HAC 60 K PSC and LMMS CAPT cryocooler.Life testing has shown to date areliability of108 cycles.Inaddition to improving cryocooler reliability, The results of theseac-tivities providewillultimatelyhastenthetransitionof cryocoolertechnologytoDoDprogramofficesanddevelopment contractors.CRYOGENIC INTEGRATION TECHNOLOGYBackgroundThe objective of this activity is to develop components that improve the cryo-genic system by reducing large system penaltiesand analysis errors.Technologies under devel-opment include a CryogenicSystems Integration Model (CSIM),60 and100 K thermalstorageunits and heat transport devices, thermalswitches,and flexible cryogenic joints andstraps. Thetechnicalchallengesto beaddressedduring component technology developmentincludesman-agement of a twophaseliquidina zero-Genvironment, poor capillary wickingof a cryogenicheat t