NASA S SPACE TECHNOLOGY MISSION DIRECTORATE (STMD) IS INVESTIGATING TECHNOLOGIES FOR THERMAL CONTROL SYSTEM…

Public award description

NASA S SPACE TECHNOLOGY MISSION DIRECTORATE (STMD) IS INVESTIGATING TECHNOLOGIES FOR THERMAL CONTROL SYSTEMS (TCS) IN HUMAN SPACEFLIGHT VEHICLES, SUCH AS VARIABLE GEOMETRY SPACECRAFT RADIATOR. THE TCS IN CREWED VEHICLES MUST MAINTAIN A RELATIVELY CONSTANT ENVIRONMENT TEMPERATURE FOR A WIDE RANGE OF EXTERNAL THERMAL ENVIRONMENTS (LOW EARTH ORBIT, TRANS-PLANETARY COAST, AND PLANETARY SURFACE OPERATIONS). THE SINK TEMPERATURE MAY VARY FROM APPROXIMATELY 70 K TO 230 K. RECENT RESEARCHES INVESTIGATED AND PRESENTED POTENTIAL OF HEAT REJECTION CAPABILITY FROM THE MORPHING COMPOSITE / SHAPE MEMORY ALLOYS (SMA) RADIATOR. THE SMA RADIATOR EMPLOYS SUCH TEMPERATURE DEPENDENT SMA MATERIALS TO PASSIVELY MORPH THE RADIATOR SHAPE AND THUS ADJUST THE RATE OF HEAT REJECTION TO A WIDE RANGE OF VEHICLE REQUIREMENTS. NONETHELESS, UTILIZING SMA MATERIALS FACES MANY DISADVANTAGES, INCLUDING LOW ACTUATION FREQUENCY, SENSITIVITY OF MATERIAL PROPERTIES IN FABRICATION, RESIDUAL STRESS S DEVELOPED IN THIN FILMS, AND NONLINEARITY OF ACTUATION FORCE. ADVANCED COOLING TECHNOLOGIES, INC. (ACT) PROPOSES TO DEVELOP A NOVEL VAPOR-PRESSURE-DRIVEN VARIABLE VIEW FACTOR RADIATOR AS A THERMAL CONTROL SYSTEM COMPONENT FOR SPACECRAFT. SIMILAR TO SMA RADIATOR MECHANISM, THE RADIATOR FOLDS INTO A TEAR DROP SHAPE TO MINIMIZE THE VIEW FACTOR WHEN COLD, AND OPENS UP TO MAXIMIZE THE VIEW FACTOR WHEN HEATED. HOWEVER, THE PROPOSED DEVICE INSTEAD UTILIZES VAPOR PRESSURE INSIDE A HOLLOW CURVED PANEL TO CHANGE THE SHAPE OF THE RADIATOR. IN PHASE I, A PROOF-OF-CONCEPT TWO-PHASE VAPOR PRESSURE DRIVEN MORPHING RADIATOR PROTOTYPE WILL BE FABRICATED AND TESTED. TEST RESULTS WILL BE USED TO VALIDATE A THERMOSTRUCTURAL MODEL, WHICH WILL BE EMPLOYED TO DESIGN THE FULL-SCALE PROTOTYPE