Multi-layer insulation (MLI)

Multi-layer insulation (MLI) is a specialized thermal barrier used primarily in spacecraft to reduce heat transfer. It consists of multiple thin layers of reflective material, such as foil or reflective films, separated by insulating spacers. These layers reflect radiant heat away, minimizing heat exchange between the spacecraft and its environment. By trapping air and using reflective surfaces, MLI effectively limits heat loss in cold conditions and prevents overheating in warmer conditions, helping maintain a stable temperature critical for sensitive equipment and systems in space.