Shuttle Breathing

Shuttle Breathing is a term typically used in reference to starships, though it could be applied aboard submarines and smaller spacecraft. The term refers to a complete failure of life support and ventilation systems, leaving the crew with nothing but currently circulating air to. It is generally considered a worst-case scenario, since even just moving the air would typically mitigate C02 buildup for slightly longer. A crew that is "shuttle breathing" is typically facing an unpleasant death without drastic and immediate measures.