OBJECTIVES: SPACE MISSIONS OFTEN INVOLVE ULTRA COLD ENVIRONMENTS AND CRYOGENIC ACTUATORS MUST BE MECHANICALLY ROBUST FOR LONG TERM CYCLIC WORK GENERATE HIGH POWER PER VOLUME AS WELL AS PERFORM HIGH PRECISION MOTION IN SUCH EXTREME ENVIRONMENTS. THESE DEMANDING REQUIREMENTS HAVE ASKED A MATERIAL SCIENTIST TO SEEK FOR A NEW TYPE OF ACTUATOR MATERIALS. RECENTLY WE DISCOVERED A BULK SCALE NOVEL INTERMETALLIC COMPOUND CAFE2AS2 THAT CAN EXHIBIT SUPER ELASTIC DEFORMATION AND ULTRA HIGH STRENGTH WHICH LEADS TO UNUSUALLY HIGH ACTUATION POWER PER VOLUME 10 TO 100 TIMES LARGER THAN MOST ACTUATOR MATERIALS AS WELL AS CRYOGENIC LINEAR SHAPE MEMORY EFFECTS EVEN NEAR 0 K. THE CRYOGENIC LINEAR ACTUATION OF THIS CRYSTAL IS EXCEPTIONALLY REPEATABLE PRECISE AND RELIABLE WITH ALMOST NO FATIGUE DAMAGE WHICH WOULD GUARANTEE THE LONG LIFETIME AND HIGH ACCURACY IN ACTUATION MOTION. THEREFORE THE RESEARCH OBJECTIVE OF THIS PROPOSAL IS TO DEVELOP A SMALL VOLUME HIGH-PRECISION AND MECHANICALLY ROBUST CRYOGENIC LINEAR ACTUATOR BY PERFORMING THE COMBINED SET OF WORKS THAT INCLUDE LARGE SINGLE CRYSTAL GROWTH OF NOVEL INTERMETALLIC COMPOUND CAFE2AS2 AND RELATED STRUCTURES EVALUATION OF THEIR CRYOGENIC LINEAR ACTUATION PERFORMANCE UNDERSTANDING OF FUNDAMENTAL PHYSICS BEHIND CRYOGENIC ACTUATION PROPERTIES AND DEVELOPMENT OF PROTO TYPE LINEAR ACTUATORS THAT OPERATES AT A TEMPERATURE BETWEEN 4 AND 150 K. THE PROJECT WILL START AS TRL 1 TO 2 BASIC PRINCIPLE OBSERVED AND END TRL 3 PROOF OF CONCEPT. APPROACH: FIRST IT IS NECESSARY TO GROW A LARGE SCALE SINGLE CRYSTAL TO OBTAIN THE ACTUATION MOTION OVER 1 MM. WE ARE CURRENTLY DEVELOPING THE CAPABILITY TO GROW MILLIMETER LENGTH SINGLE CRYSTAL CAFE2AS2 AND RELATED STRUCTURES BY USING SOLUTION GROWTH IN TIN FLUX. WE WILL BE ABLE TO SCALE UP THE CRYSTAL SIZE BY OPTIMIZING TEMPERATURE PRESSURE TIME CONDITION. SECOND IN ORDER TO CHARACTERIZE ITS CRYOGENIC ACTUATION PERFORMANCE WE ARE GOING TO USE IN SITU CRYOGENIC MICRO COMPRESSION TESTS IN SCANNING ELECTRON MICROSCOPE. ESPECIALLY A THERMAL CYCLING TEST WILL BE PERFORMED UNDER VARIOUS TEMPERATURE AND STRESS CONDITIONS AND ADVANCED COMPUTER SIMULATIONS WILL ALSO BE CONDUCTED TO UNDERSTAND FUNDAMENTAL ACTUATION MECHANISMS OF CAFE2AS2 AND RELATED STRUCTURES. THIRD IT SHOULD BE DESIRABLE TO CREATE A PROTOTYPE DEVICE AND EVALUATE ITS CRYOGENIC ACTUATION PERFORMANCE. WE WILL DESIGN A PROTOTYPE LINEAR ACTUATOR THAT CONTAINS THE STACK OF CRYSTALS TO OBTAIN THE LINEAR ACTUATION MOTION OVER 1 MM AND EVALUATE ITS CRYOGENIC ACTUATION PERFORMANCE AT A TEMPERATURE BETWEEN 4 AND 150 K WHICH INCLUDES ACTUATION LENGTH MOTION PRECISION ACTUATION POWER AND FATIGUE BEHAVIOR. POTENTIAL IMPACT: THE CRYOGENIC LINEAR ACTUATION CAPABILITY OF NOVEL INTERMETALLIC COMPOUND CAFE2AS2 AND RELATED STRUCTURES WOULD HAVE THE GREAT POTENTIAL TO DEVELOP A NEW TYPE OF CRYOGENIC LINEAR ACTUATORS. DUE TO THEIR SUPER ELASTICITY AND HIGH STRENGTH IT IS POSSIBLE TO GENERATE ULTRA HIGH ACTUATION POWER PER VOLUME 10 TO 1000 TIMES HIGHER THAN MOST ENGINEERING MATERIALS. ALSO BECAUSE THERMAL ACTUATION OF CAFE2AS2 DOES NOT INVOLVE ANY DISLOCATION MECHANISMS CRYOGENIC ACTUATION DOES NOT DEVELOP ANY FATIGUE DAMAGES. FURTHERMORE COBALT OR STRONTIUM ADDITION OR QUENCHING ANNEALING CAN TUNE THE PHASE DIAGRAM AND IT IS POSSIBLE TO ADJUST CRYOGENIC ACTUATION CAPABILITY TO MEET SPECIFICS AND NEEDS. THEREFORE OUR NOVEL INTERMETALLIC COMPOUNDS WOULD ALLOW US TO MINIMIZE THE DEVICE VOLUME WITHOUT SACRIFICING ACTUATION POWER AND TO OBTAIN HIGH PRECISION AND RELIABLE CRYOGENIC LINEAR ACTUATORS. COLLABORATION SUCH AS MATERIAL SUPPORT WITH PROF. PAUL CANFIELDS GROUP OF IOWA STATE UNIVERSITY WILL BE EXPECTED.