Some Thoughts on Satisfying Spacecraft Passivation Requirements

Most spacecraft have at least one pressurized vessel on board. In addition to a hole, it is possible that a pressure vessel may experience catastrophic failure (i.e. rupture) as a result of a hypervelocity impact. If a tank rupture were to occur on-orbit following a micrometeoroid or orbital debris particle impact, for example, not only could it lead to loss of life, but it would also generate a tremendous amount of debris that could compromise future space assets working in similar orbits. As a result, NASA and other space faring nations have put in place spacecraft design requirements to prevent additional sizable debris from being created in the event of pressure vessel rupture or catastrophic failure. In general, these requirements state that a spacecraft’s stored energy devices are to be passivated at the end of a spacecraft’s mission or useful life. Programs whose spacecraft designs are not be able to comply with some aspects of those requirements employ an alternative, so-called “soft passivation”, option. This paper provides a summary of a project performed with the intent of providing some possible guidelines and considerations that can be used by satellite programs to help satisfy passivation requirements using a “soft passivation” approach, that is, when not able to perform complete hard passivation