Off-normal Situations Related to the Operation of the Electron-VM Oxygen Generation System aboard the International Space Station

The Electron-VM Oxygen Generation System (OGS) is a main source of oxygen for crew breathing on the International Space Station (ISS) and the result of updating the Electron-V OGS that has been in successful operation for 17 years on Mir Space Station. The successful accomplishment of a manned flight program primarily has resulted in the stable operation of the system.

The paper deals with analysis of off-normal situations related to the operation of the Electron-VM on board ISS. The system switching-off analysis based on the telemetry information processing and the results of the additional tests conducted under flight and ground conditions is performed.

A principal cause of system switching-offs is a reduction in the pressure built by the circulating pumps due to ingress of gas bubbles into the suction pipeline. The results of the Electron-VM OGS switching-off analysis and the practical recommendations regarding its prevention are reviewed.

The serviceability restoration technique for the Electron-VM's key unit (the liquid unit) has been developed and tested under manned flight conditions. The liquid unit has been restored under flight conditions and being integrated in the Electron-VM is currently operated successfully on the ISS.