Analysis of Concept Feasibility and Results of Numerical Simulation of a Two-Stage Space Radiator With Variable Emissivity Coating

We present analytical models and a detailed numerical model of a two-stage space radiator with variable emissivity coating on its internal surfaces and we correlate them with experimental data to validate the numerical model. The feasibility of the radiator concept called VESPAR (Variable Emittance SPAce Radiator) is proven using an analytical model and confirmed by a numerical model. This numerical model is then used to compare the thermal performance of VESPAR and a conventional flat radiator. The comparison confirmed that the VESPAR radiator for satellite thermal control could lead to power savings for survival electric heaters or even its elimination.     

Infrared fibers for radiometer thermometry in hypothermia andhyperthermia treatment

Hypothermia is a condition which results from prolonged exposure to a cold environment. Rapid and efficient heating is needed to rewarm the patient from 32-35 degrees C to normal body temperature. Hyperthermia in cancer treatment involves heating malignant tumors to 42.5-43.0 degrees C for an extended period (e.g., 30 min) in an attempt to obtain remission. Microwave or radio frequency heating is often used for rewarming in hypothermia or for temperature elevation in hyperthermia treatment. One severe problem with such heating is the accurate measurement and control of temperature in the presence of a strong electromagnetic field. For this purpose, we have developed a fiberoptic radiometer system which is based on a nonmetallic, infrared fiber probe, which can operate either in contact or noncontact mode. In preliminary investigations, the radiometer worked well in a strong microwave or radiofrequency field, with an accuracy of +/- 0.5 degrees C. This fiberoptic thermometer was used to control the surface temperature of objects within +/- 2 degrees C.