HIGHLY REFLECTING LIQUID FILMS

THE CONCEPT OF THIN LIQUID FILM MEDIATED PROTECTION FROM LASER IRRADIATION WILL BE APPLIED TO HEAT SHIELD MATERIALS. THE CONCEPT EMPLOYS A THIN METAL FILM WHICH BECOMES LIQUID DURING IRRADIATION. THE FILM IS DESIGNED TO BE HIGHLY REFLECTING TO LASER IRRADIATION WITHOUT INTERFERING WITH THE VAPORIZATION THERMODYNAMICS OF THE HEAT SHIELD. THIS CONCEPT PROVIDES LASER HARDENING IN AN EXO ENVIRONMENT. AT ENDO ALTITUDES, THE THIN FILM WILL NOT INTERFERE WITH THE HEAT SHIELD FUNCTION. A COMBINED THEORETICAL-EXPERIMENTAL PROGRAM IS PROPOSED. THE THEORETICAL EFFORT WILL DETERMINE THE RANGES OF LASER PARAMETERS FOR WHICH HIGH REFLECTIVITY WILL BE MAINTAINED AND IDENTIFY CADIDATE COATING MATERIALS. CANDIDATE MATERIALS WILL BE SCREENED FOR HIGH REFLECTIVITY, AND FOR STABLE LIQUID PHASE OVER REQUIRED TEMPERATURE RANGES. METAL ALLOYS WILL BE GIVEN PARTICULAR ATTENTION AS CANDIDATE MATERIALS. CONSIDERATION WILL BE GIVEN TO NUCLEAR HARDENING POTENTIAL. THE EXPERIMENTAL PORTION OF THIS PROGRAM WILL TEST CHOSEN CANDIDATE MATERIALS FOR HIGH REFLECTIVITY AND FILM STABILITY UNDER SIMULATED LASER INTERACTION. MEASUREMENTS WILL BE PERFORMED BYE-BEAM HEATING. FILM STABILITY, HEAT OF VAPORIZATION AND OPTICAL REFLECTIVITY WILL BE DETERMINED IN ORDER TO DETERMINE Q*.