The Oxygen Generation System produces oxygen for breathing by the crew and laboratory animals, as well as for replacement of oxygen lost due to experiment use, airlock depressurisation, module leakage and carbon dioxide venting. The system consists mainly of the Oxygen Generation Assembly and a Power Supply Module.
The Oxygen Generation Assembly electrolyses water provided by the Water Recovery System, yielding oxygen and hydrogen. The oxygen is delivered to the cabin atmosphere, and the hydrogen is vented overboard. The Power Supply Module provides the power needed to electrolyse the water.
The Oxygen Generation System is designed to generate oxygen at a selectable rate and is capable of operating both continuously and cyclically. It provides up to 9 kg of oxygen per day during continuous operation and a normal rate of about 5.5 kg of oxygen per day during cyclic operation.