CONTROLLED EMITTANCE MATERIAL FOR IR SIGNATURE SUPPRESSION APPLICATIONS

SKIN COATINGS FOR IR SIGNATURE SUPPRESSION REQUIRE MORE THAN SIMPLE EMISSIVITY CONTROL. CONTROL OF THE DIRECTIONAL DISTRIBUTION OF EMITTED/REFLECTED RADIATION AND ACTIVE HEATING OR COOLING ARE ALSO NECESSARY. THE RADIANCE FROM THE OBJECT NEEDS TO APPROXIMATE THE RADIANCE FROM THE BACKGROUND OVER A BROAD RANGE OF VIEWING ANGLES. THIS REQUIRES A COMPLICATED BIDIRECTIONAL REFLECTANCE DISTRIBUTION FUNCTION (BRDF) FOR THE COOLING MATERIAL. TO ACHIEVE THIS BRDF THE APPROPRIATE SETS OF EMISSIVITY, TEMPERATURE, AND DIRECTIONAL DISTRIBUTION CONTROLS NEED TO BE SELECTED AND COMBINED. THE RESULTING SKIN RADIANCES NEED TO BE COMPUTED FOR REALISTIC DISTRIBUTIONS OF EXTERNAL RADIANT SOURCES, OBJECT SURFACE TEMPERATURES, AND VIEWING GEOMETRIES TO INSURE THAT THE DESIGN PRODUCES CONTRAST RADIANCES THAT ARE BELOW THE DETECTION THRESHOLD. BECAUSE OF THE COMPLEXITY, THE R&D PROCESS REQUIRES A ROBUST SIGNATURE MODELING CAPABILITY TO SELECT AND OPTIMIZE THE MATERIAL AND CONTROL PARAMETERS. THE PROPOSED EFFORT WILL 1. SPECIFY SURFACE BRDFS THAT PRODUCE CONTRAST RADIANCES THAT ARE BELOW DETECTION THRESHOLD; 2. IDENTIFY TECHNOLOGIES AND MATERIAL PROPERTIES THAT COULD POTENTIALLY ACHIEVE THE SPECIFIED BRDFS; 3. SPECIFY NEEDED MODIFICATIONS, IF ANY, TO AERODYNE'S SIGNATURE MODELING CODE SPIRITS; AND 4. ASSESS THE FEASIBILITY OF ACHIEVING THE SPECIFIED BRDFS WITH EXISTING MODULATION TECHNOLOGIES AND IR MATERIALS.