Design and operational practices for the passivation of spacecraft and launchers at the end of life

Abstract

Passivating spacecraft and upper stages at the end of their operational life is a must: numerous in orbit break-ups have been encountered by all space operators due to a lack of proper passivation leading to an explosion triggered by mixture of hypergolic propellants, pressure buildup, or hyper-velocity collision with a small object. The following paper recalls first the high level guidelines that have to be adopted at international level to achieve proper space debris mitigation, recalls the definition of passivation, then describes the most frequent solutions currently adopted. Several examples, mainly from India and China, are quoted, extracted generally from IADC presentations; they are presented in italics, unmodified. The paper then reviews briefly the main problems encountered during the process of designing the passivation system and operating it.