Spacecraft engineering often depends on materials that perform reliably under conditions far more extreme than those encountered on Earth. An article in IEEE Spectrum examines one of the less visible but critically important challenges facing spacecraft designers: outgassing. This phenomenon occurs when materials release trapped gases or volatile compounds in the vacuum of space, potentially contaminating sensitive instruments and degrading mission performance.
The article focuses on adhesives, which are widely used in spacecraft assembly to bond components, secure wiring, and support delicate structures. While an adhesive may appear stable under terrestrial conditions, exposure to the near-perfect vacuum of space can cause it to release molecular residues. These emissions can settle on optical sensors, solar panels, mirrors, and other precision equipment, reducing efficiency and accuracy.
To minimize such risks, NASA has developed rigorous testing standards for materials intended for spaceflight. Engineers evaluate products based on measurements such as Total Mass Loss (TML) and Collected Volatile Condensable Materials (CVCM). These metrics help determine how much material evaporates in vacuum conditions and how much of that vapor is likely to condense onto nearby surfaces. Only materials meeting strict thresholds are approved for use in many spacecraft applications.
The article highlights that outgassing is not limited to adhesives. Plastics, coatings, sealants, and numerous other materials can present similar concerns. As spacecraft become more sophisticated and incorporate increasingly sensitive instruments, controlling contamination has become a fundamental aspect of mission design. Engineers must carefully balance mechanical performance, durability, weight, and contamination risk when selecting materials.
The discussion underscores the importance of seemingly routine engineering decisions. A small amount of outgassed material can have outsized consequences when deposited on a telescope lens or scientific sensor operating millions of miles from Earth. As a result, material qualification has evolved into a highly specialized discipline within aerospace engineering.
By shedding light on NASA’s standards and testing methods, the article illustrates how successful space missions often depend not only on advanced propulsion or electronics but also on a deep understanding of the materials that hold spacecraft together.