SHUNTING DIELECTRIC SENSING SYSTEM FOR NUTRIENT DELIVERY

THIS PROPOSAL DESCRIBES AN SBIR PROJECT TO DESIGN A REMOTE MOISTURE DETECTION SYSTEM TO SUPPORT PLANT GROWTH IN SPACE. THIS SYSTEM CAN BE BUILT INTO AN AUTOMATED IRRIGATION SYSTEM TO MAINTAIN A THIN LAYER OF NUTRIENT SOLUTION ON A SURFACE OCCUPIED BY THE ROOTS AND PLANTS. THESENSOR IS ELECTRICALLY ISOLATED FROM THE ROOT SYSTEM AND IS CONFIGURABLE TO MEASURE THE THICKNESS OF A THIN LAYER ON A SURFACE AND TO BE LAMINATED INTO THE SURFACE. THERE PRESENTLY EXISTS NO SENSOR THAT COMBINES ALL OF THESE FEATURES. THE TECHNICAL PROBLEMS ATTENDING THE GROWTH OF PLANTS IN SPACE REQUIRE SOME FORM OF IRRIGATION CONTROL, ANDTHE PROPOSED INNOVATION SHOULD PROVIDE A DEGREE OF ACCURACY UNOBTAINABLE BY OTHER METHODS. BRIEFLY, THE SENSOR OPERATES BY CONTINUOUSLY MEASURING THE DIELECTRIC PROPERTIES OF MATERIAL ADJACENT TO THE SENSOR. THE HIGH-FREQUENCY RESPONSE OF THE SENSOR IS CORRELATED TO ADATABASE THAT IS PROGRAMMED INTO THE SOFTWARE OF THE MONITOR. THE VERSATILITY OF THIS TECHNIQUE ALLOWS FOR THE POSSIBILITY OF MEASURING OTHER PROCESS VARIABLES IN ADDITION TO THE MOISTURE CONTENT OF THE PLANT-GROWTH SURFACE.