Multilayer insulation for spacecraft applications

Abstract

Multilayer Insulation (MLI) blankets provide a lightweight insulation system with a high thermal resistance in vacuum. MLI blankets are utilized to reduce heat loss from a spacecraft to the cold space, or to prevent excessive heating of the surroundings from an internal component with heat dissipation. MLI blankets consist of a number of highly reflecting radiation shields interspaced with a low thermal conductivity spacer material or separated by crinkling the radiation shields themselves. The radiation shields are generally a plastic film metalized on either one side or both sides of the film. The principle of an MLI blanket is to use multiple layers of radiation shields to reflect back, in the opposite direction of heat flow, a large percentage of the radiant heat flux reaching each radiation shield. MLI is therefore very effective if solid conduction through the spacers and gaseous conduction through the gas medium can be minimized.