"On Saturday night, following all the required checks, the crew put into operation the oxygen set and we like how it is working", he said.
The replaced unit was the last they have in the ISS and, if it gets broken, there's no other substitute: they will have to wait for another arrival of the Russian Progress space truck.
Problems with the Russian oxygen set began over a month ago. Crew commander Mickael Foale and engineer Alexander Kaleri have already tried to rehabilitate the Elektron but could not because the faulty unit had to be replaced. To maintain the required oxygen composition the crew periodically burnt oxygen sticks found aboard and made use of reserve oxygen brought in by the Progress M1-11 space truck.
Michael Foale and Alexander Kaleri installed a new liquid oxygen unit in the set on March 18. The Elektron will later be modified.