CONCENTRATOR TECHNOLOGY

DEVELOPMENT OF SOLAR POWERED ROCKET PROPULSION SYSTEMS DEPENDS HEAVILY ON DEMONSTRATING THE TECHNOLOGY FOR LIGHTWEIGHT SPACE-DEPLOYABLE SOLAR CONCENTRATORS. LARGE PARABOLICALLY SHAPED THIN FILM REFLECTORS CAN BE PACKAGED WITH OTHER SOLAR POWERED PROPULSION ELEMENTS AND DEPLOYED IN LOW EARTH ORBIT. THIN FILM CASTING AND COATING TECHNIQUES FOR FABRICATING SEAMLESS AND GORELESS CONCENTRATORS HAS BEEN DEMONSTRATED. THESE FABRICATION PROCESSES USE NEWLY POLYAMIDE MATERIALS SUPPLIED BY LANGLEY RESEARCH CENTER (LARC). ALTERNATIVE CONCENTRATOR CONCEPTS, SUCH AS INTEGRAL TORUS/CONCENTRATORS, MADE POSSIBLE BY SPRAY CASTING FABRICATION TECHNIQUES WILL BE EVALUATED. THE PHASE I EFFORT WILL SELECT A SINGLE PRELIMINARY DESIGN THAT WILL BE USED TO FABRICATE A 7X9 METER OFF-AXIS PARABOLIC SOLAR CONCENTRATOR UNDER THE PHASE II EFFORT. THE MEMBRANE FABRICATION PROCEDURES WILL BE DEFINED IN PHASE I. EXISTING CASTING AND CURING EQUIPMENT WILL BE REVIEWED AND MODIFICATIONS NECESSARY TO CONSTRUCT THE 7X9 METER CONCENTRATOR WILL BE IDENTIFIED. THIS EFFORT CONTINUES TO SUPPORT THE SOLAR THERMAL PROPULSION PROGRAM THROUGH FURTHER TECHNOLOGY DEVELOPMENT OF FABRICATION TECHNIQUES FOR DOUBLY-CURVED MEMBRANE OFF-AXIS PARABOLOIDAL SOLAR CONCENTRATORS. THIS TECHNOLOGY INVOLVES SPIN OR SPRAY CASTING OF POLYAMIDE FILMS THAT CAN BE USED FOR CONCENTRATORS HAVING LOW WEIGHT\AREA AND HIGH CONCENTRATION RATIOS. SOLAR THERMAL PROPULSION, SOLAR DYNAMIC SYSTEMS, LUNAR SOIL PROCESSING AND LARGE RF AND MICROWAVE ANTENNAS ARE TYPICAL APPLICATIONS THAT WOULD BENEFIT FROM POLYAMIDE CONCENTRATORS. ALSO REDUCED COST THIN FILM HELIOSTATS COULD BE USED IN PLACE OF A SECOND SURFACE GLASS MIRROR FOR TERRESTRIAL APPLICATIONS. THIS WOULD DECREASE THE COST OF THE HELIOSTAT RESULTING IN A MORE COST-EFFECTIVE POWER SOURCE FOR SOLAR FURNACES AND SOLAR DYNAMIC SYSTEMS.