Kapton Flexible Heaters Meet Stringent Demands in Thermal Vacuum Testing Chamber

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The Challenge

Space systems (i.e., spacecraft, satellites, etc.) and related parts have to undergo stringent testing as part of their design, development, and validation protocols. Since it’s not generally practical to test in actual deep space, an alternative is a simulated environment using a thermal vacuum chamber (TVC). These extreme space vacuum conditions include high temperatures input and control. The customer, an aerospace testing service, needed an enhanced method of heating to compliment the vacuum environment to better detect potential deep space environment related failures during testing in the TVC. They provide testing services to some of the biggest industry related OEMs in the world. Of particular importance, to both the customer and their end users, were past issues with thermal control and outgassing. This enhanced thermal management system had to fit seamlessly with their current hardware, deferent TVC units from different manufacturers, for thermal conductivity.

The Solution

The first step for the Chromalox team was to collaborate with the customer to understand the applicable equipment, processes and end uses. To start with, the choice was a Kapton® flexible heater design due to the polyimides unmatched ability not to outgass. Next, with the use of thermal modeling, we designed buried sensors (some were custom etched with an exotic metal with enhanced resistivity) for the required linear thermal detection and control. This was especially important to the customer since thermal transfer between the heating element and the heatsink behave differently in a vacuum (the transfer of heat in a vacuum is no longer convection since there is no air). In other words, in a deep space vacuum environment, hot parts want to stay hot and cold parts want to stay cold, resulting in stress related malfunctions. Next, the proper bonding method included a modified cross-linked adhesive to further mitigate outgassing. This bonding method allowed for better and more efficient thermal conductance through their existing exchange plates. Finally, we worked with the customer’s controls team to provide the sensor interface with the existing thermal control units (TCU) for both electrical and nitrogen feed.

The Benefits

Chromalox met all of the customer’s expectations. Our Kapton® heater and related design solutions are now used on both large and small TVC equipment for better testing under simulated space conditions. The customer now has the required control of slope rate (temperature change); enhanced uniformity over both gaseous and liquid nitrogen feed, no outgassing, and a software interface for data collection. As a result, potential problems can now be detected more quickly with more precision in the design, testing, and validation phases. In addition, the customer was able to transfer some of our synergetic thermal solutions to another related product line (thermal shock chambers), as well. The benefits of this thermal solution encompass many other industries and applications besides aerospace (i.e., aeronautical, satellites, defense, military, astronomy, etc.). This is another example of how Chromalox collaborates with customers towards solving problems with innovative cost-saving solutions.