Study on Thermal Resistance Characteristics and Thermal Validation of Indium Foil-Filled Thermal Interfaces for Space Cameras

On-orbit space cameras face high heat dissipation and non-ideal thermal contact interfaces. Thermal interface material (TIM) performance affects detector stability and imaging quality. However, traditional fillers are not clearly suitable for large-area, low-pressure, and non-ideal conditions. This paper assumes that embossed indium foil compensates for interface irregularities at micro and macro scales. It thus reduces interface thermal resistance (ITR). We propose embossed indium foil as a TIM. We build an evaluation framework from surface thermal resistance to component-level validation. Experiments are conducted on a steady-state heat flux platform. We measure ITR of four foil thicknesses (0.1–0.3 mm) under different pressures (0.17–1.38 MPa) and temperatures (10–30 °C). Results show strong pressure dependence. At low pressure (<0.6 MPa), thinner foils perform better due to lower bulk resistance. At high pressure (>0.6 MPa) and large area (0.06 m2), thicker foils show advantages. Their higher plasticity better compensates surface errors. Engineering tests confirm the method’s effectiveness. A 0.285 mm embossed indium foil reduces ITR from 3055 to 750 mm2·°C·W−1, a 75.5% reduction. This study proves embossed indium foil fills micro-gaps and compensates macro-shape errors. It provides quantitative support for spacecraft thermal design.