From 10,000 meters above sea level to deep space: How heating elements protect aerospace equipment

We all know that ordinary electronic products struggle to operate in extreme environments. However, spacecraft cruise at altitudes of tens of thousands of meters, and satellites exist in a vacuum, lacking the protection and temperature regulation of the atmosphere. Their operating environments are extremely harsh. Heating elements play an indispensable role in ensuring the normal operation of spacecraft and satellites in such complex environments.

What is a Heating Element?

A heating element is a flexible, integrated heater with controllable thickness, formed through a high-temperature hot-pressing curing process. It boasts advantages such as high flexibility, thinness, high insulation strength, non-toxicity, and good heat resistance, making it suitable for heating applications requiring small areas and lightweight construction. It is generally divided into PI heating elements and silicone heating elements.

A typical structure consists of an inner layer made of heating circuitry from brass, stainless steel, or iron-chromium-aluminum alloys to generate heat; and an outer layer using polyimide film or silicone sheet as an insulating covering to ensure safety and structural stability.

PI and silicone heating elements are widely used not only in consumer electronics and industrial fields but also in aerospace, providing safety assurance for the operation of spacecraft and satellites.

Aviation Applications of Heating Surface Mounts – Aircraft De-icing

Why is anti-icing and de-icing necessary?

Commercial aircraft typically cruise at altitudes up to 12,000 meters, where cabin temperatures can drop to -40 to -50°C. Such low temperatures can easily cause critical components such as electronic equipment and sensors to malfunction. Simultaneously, the surfaces of instruments, sensors, and lenses may accumulate moisture and fog, leading to operational problems.

Furthermore, aircraft icing alters the aircraft's aerodynamic shape, deteriorating its aerodynamic performance and directly impacting stability and handling. Therefore, aircraft anti-icing systems represent the highest level of aircraft safety.

For example, pitot tube icing can have catastrophic consequences. It can prevent pilots from accurately assessing the aircraft's status and making correct control decisions. In extreme cases, such as the Air France AF447 accident, ice crystals blocked the pitot tube, causing inconsistent airspeed readings on both sides, ultimately triggering a chain reaction that led to the aircraft stalling and crashing.

Aircraft Icing and De-icing Principles
Aircraft icing refers to the phenomenon where ice layers form on the surfaces of aircraft components during flight due to the freezing of water droplets or the sublimation of water vapor. Common types of icing include:

"Dry icing" occurring in ice crystal clouds;

"Sublimation icing" formed by the direct sublimation of water vapor;

And the most common, "droplet icing," formed when supercooled water droplets impact and freeze on the aircraft surface.

To address aircraft icing, aircraft engineers employ various anti-icing and de-icing methods. These primarily include liquid anti-icing and thermal anti-icing. The latter, depending on the heat source, can be further divided into gas-thermal anti-icing and electrothermal anti-icing.

Electrical thermal anti-icing systems primarily use electrically heated elements to heat the surfaces of components to prevent icing. The most common applications are windshields, propellers, and pitot tubes. Due to its low power loss and uniform heating, electrothermal anti-icing is widely used in modern large commercial airliners.

In addition, heating elements can be integrated into locations such as the leading edge of wings, tail fins, and engine air intakes to periodically remove small amounts of ice buildup through intermittent heating. This solution is energy-efficient, has a fast response time, and offers precise control, making it particularly suitable for small aircraft and drones, effectively ensuring flight safety with low energy consumption.

Inside aircraft, PI heating elements also play a crucial role: they provide stable heating for instruments, sensors, and lenses, preventing them from failing in the high-altitude, low-temperature environment. Thanks to their low gas release rate and resistance to extreme temperatures and humidity, PI heating elements can precisely conduct heat, effectively dissipating moisture and preventing fogging, while avoiding damage to precision equipment.

Aerospace Applications of Heating Elements – Satellite Thermal Control

Why is satellite thermal control needed?

Outer space presents a harsh environment with extreme high and low temperatures and drastic temperature fluctuations. Especially when satellites are in low Earth orbit, their external thermal environment undergoes drastic changes, with temperature fluctuations ranging from -150°C to 150°C. To maintain the normal operation of their onboard equipment and maximize its service life, satellites need to be equipped with thermal control systems to ensure they operate within a suitable temperature range.

Satellite Thermal Control – Passive and Active Thermal Control
Satellite thermal control is broadly categorized into passive and active thermal control based on whether it consumes energy.

Passive thermal control primarily relies on the physical properties of materials and structural design to regulate temperature. Examples include applying thermal control coatings with different properties to the satellite's outer shell, using multi-layered insulation materials, and installing heat pipes or radiators. While this technology is highly reliable as it does not rely on feedback control, it cannot adjust in real-time to environmental changes, resulting in lower controllability.

Active thermal control technology uses the satellite's temperature as the control feedback, actively adjusting radiation and thermal conductivity parameters, and actively heating and cooling to maintain the satellite's temperature. The most typical application is an electric heating thermostat, which uses heating elements such as electric heating plates to heat components requiring temperature maintenance.

With the increasing complexity of outer space exploration missions, thermal control components need to meet four requirements: low weight, low energy consumption, high precision, and high response speed. Against this backdrop, heating elements, with their rapid heating, chemical corrosion resistance, uniform heat distribution, and long service life, have become an ideal choice for heating satellites and payloads in deep space environments. By directly connecting heating elements to components, equipment and machinery can quickly receive the appropriate operating temperature. Furthermore, because heating elements provide uniform heat transfer, uneven heating or cold spots are avoided, ensuring stable equipment operation.

As a core component of aircraft thermal control systems, heating elements provide necessary heat to critical equipment and structural parts, ensuring stable operation within set temperature ranges. Today, the role of heating elements in the aerospace field far exceeds that of a simple heating element.

From aircraft anti-icing and de-icing to satellite precision thermal control, the development trajectory clearly points to flexibility, lightweighting, and intelligence. Against this backdrop, the new generation of flexible heating elements, represented by PI heating elements, is gradually becoming an important technological direction in the aerospace thermal control field due to their high performance and high adaptability.