Considerations for Exempting Spacecraft Units from Thermal Vacuum Testing

For spacecraft whose missions are considered low risk, it is typical for units to be subjected to unit-level thermal cycle and thermal vacuum testing. In recent years, however, the desire to reduce program costs and shorten development schedules has the aerospace testing community questioning the value of thermal vacuum testing all units. There may be instances where unit-level thermal vacuum testing is unnecessary if it can be shown that the unit’s design and performance is insensitive to the vacuum environment and that failures associated with the vacuum environment can be detected in other unit-level testing. The prescription of conditions under which unit thermal vacuum testing may be exempted should focus on establishing proven heritage, demonstrating design robustness through analysis and development testing, and reducing incurred risk. A general list of considerations by which vacuum-sensitivity may be assessed is provided herein.