International Space Station Automated Safing Responses to Hazardous Atmosphere

Environmental Control and Life Support (ECLS) system functionality aboard the International Space Station (ISS) includes responding to various emergency conditions. The ISS requirements define three types of emergencies: fire, rapid depressurization, and hazardous or toxic atmosphere. The ISS has automatic integrated vehicle responses to each of these emergencies. These automated responses are designed to aid the crew in their response actions to the emergencies.

The response to a hazardous atmosphere on board the ISS, including the automatic integrated vehicle response and crew actions, is the focus of this paper. Philosophies regarding the detection of and response to emergencies involving chemical releases are described. Vehicle configuration is discussed for currently supported automatic responses, and crew actions are defined for modules on orbit up to the addition of the Docking Compartment (DC1) in the assembly sequence. Recommendations for future improvements are also presented.