Passivation of Spacecraft Pressure Vessels: Some Comments on Requirements, Principles, and Practices

Many space-faring organizations have requirements to limit the growth of orbital debris by passivating spacecraft that remain in orbit after mission end. These requirements state that a stored energy devices are to be fully depleted at the end of a spacecraft’s useful life. Spacecraft designs not able to comply with those requirements use a so-called “soft passivation” option. This report presents the results of two studies aimed at better understanding spacecraft pressure vessel passivation state-of-the-art. They summarize current practices and principles of pressure vessel passivation and present an approach that can be used to show that spacecraft propulsion system passivation has been achieved.