NEW FABRICATION METHODS FOR DIMENSIONALLY STABLE GRAPHITE/MAGNESIUM SPACE STRUCTURES

OUR RECENT EFFORTS IN FABRICATING THIN-GAUGE GRAPHITE/MAGNESIUM COMPOSITES HAVE RESULTED IN THE FIRST SUCH MATERIAL TO HAVE A ZERO COEFFICIENT OF THERMAL EXPANSION AND NO PERCEPTIBLE DIMENSIONAL HYSTERESIS DURING CYCLING OVER THE ENTIRE ORBITAL TEMPERATURE RANGE OF -250 DEGREES FAHRENHEIT, EVEN AFTER 100 CYCLES. COUPLED WITH DENSITY OF LESS THAN 2 GRAMS PER CUBIC CENTIMETER, TENSILE STRENGTH OVER 70 KSI, AND YOUNG'S MODULUS OVER 50 MSI, THIS THERMAL EXPANSION BEHAVIOR MAKES THE MATERIAL EXTREMELY ATTRACTIVE FOR LARGE ORBITING SPACE STRUCTURES. THIS PROGRAM SEEKS TO DEVELOP TECHNIQUES FOR FABRICATING THIN-GAUGE, NET-SHAPE COMPONENTS IN COMPLEX GEOMETRIES AND FACILITATING JOINING INTO SUCH STRUCTURES. PHASE I WILL ESTABLISH FEASIBILITY OF USING A NOVEL ISOSTATIC PRESSURIZATION SYSTEM TO MOLD SUCH COMPONENTS; PHASE II WOULD DEVELOP FULL-SCALE PROTOTYPE COMPONENTS FOR EVALUATION.