Russia's Elektron, one of three oxygen regeneration systems on board the International Space Station (ISS), failed in mid-September, forcing the crew to switch it off.
"Elektron-VM was switched back on Tuesday at 2:08 p.m. Moscow time [11:08 a.m. GMT], and we can safely say that is now operating normally," said Igor Panarin, spokesman for the Russian Space Agency.
The ISS crew turned the system off September 17 after the U.S. Space Shuttle Atlantis undocked from the station. When the crew reactivated the system the following day, they smelled an unpleasant odor and switched it off again.
Alexei Krasnov, head of the Russian space agency's manned program, said a week after the incident that the failure would cause no serious problems for the ISS crew, as the station has two backup systems.
The Elektron failure has not been the only technical difficulty to plague the ISS recently. An initial attempt to dock a Progress supply vehicle failed October 27 when a guidance antenna did not fold away properly. The second attempt was successful.