Triton Systems is developing an unpowered, self-switching variable thermal radiance technology we call the Phase Change Thermochromic Radiator (PCTR) for active temperature control of spacecraft surfaces. PCTR automatically changes from low to high infrared emissivity above a designed temperature setpoint, causing a surface in space to radiate heat only when it exceeds a critical temperature. The principle of operation involves a phase change compound integrated into a thin film multilayer less than 2 µm thick. Whereas previous demonstrations of PCTR have shown transition temperatures only down to 30°C, the proposed program will reach temperatures of -10°C and possibly as low as -25°C. The new generation of PCTR will be capable of meeting the demands of manned space vehicles, planetary probes and landers, including manufacturability in areas of 10's of square meters
Subject technology applies to the 2015 NASA Technology Roadmap, TA14, which call for thermal systems with reduced mass, reduced power requirements, enhanced performance, and increased reliability and survivability in hostile environments. Area 14.2 relates to Thermal Control Systems able to maintain vehicle surfaces and internals within an appropriate temperature range, and Sub-area 14.2 describes mid-temperature (-150 to 500°C) Heat Rejection and Storage.
Defense applications of emittance control films will include satellites, thermal signature for ships, aircraft, UAVs and land vehicles. Commercial applications will be for thermophotovoltaics, or architectural energy control for roofs, windows and walls.