NASA officials remain mystified as to why the leak erupted. Ammonia already had been seeping ever so slightly from the location, but the flow increased dramatically Thursday.
Montalbano did not know, as of Saturday evening, how much ammonia was lost. Another spacewalk will be needed to replenish the supply.
With the repair work behind them, the astronauts and ground controllers turned their attention to the impending departure of three of the six crewmen.
Marshburn has been on the space station since December and is set to return to Earth late Monday, along with Hadfield, a Canadian, and Russian Roman Romanenko. Cassidy is a new arrival, on board for just 1½ months.
By coincidence, the two Americans performed a spacewalk at this troublesome spot before, during a shuttle visit in 2009.
“This type of event is what the years of training were for,” Hadfield said in a tweet Friday. “A happy, busy crew, working hard, loving life in space.”