Aluminium & Gold in Satellite Thermal Protection: Multi‑Layer Insulation & Metal Plating Explained

A satellite travels at incredible speeds, encountering atmospheric conditions and temperature fluctuations not experienced within the Earth’s atmosphere. For this reason, the materials used to construct and protect satellite components must be chosen with particular care and consideration.

Thermal and Atmospheric Considerations

Although the sun’s extremely powerful light and heat is absorbed and dispersed by the earth’s atmosphere, this is not the case in the atmospheres in which satellites orbit. For this reason, the satellite must be protected from exposure to light, heat and direct radiation. Additionally, UV radiation in the upper atmosphere produces atomic oxygen when exposed to oxygen atoms. This can result in undesirable oxidation and corrosion.

As satellites orbit, meteoric debris can cause damage to coatings, platings and structures. For this reason, the materials used to coat and plate satellites must be able to resist high impacts and retain their strength. Thermal conditions change rapidly as satellites reach speeds of around seven kilometers per second.  These rapid environmental changes can result in coating degradation and insulation challenges.

Popular Materials for Coating and Insulation

Satellite designers commonly use aluminium alloys to insulate satellites. Aluminium is widely admired for its low weight, durability, availability and cost-effectiveness. Multi-layer insulation, for example, contains aluminium in the form of aluminized polyimide. Where insulation requires additional reinforcement with plating, gold is a popular choice for internal components. Designers also use silver for internal plating of satellite components and copper for electronic applications such as circuit boards.