Cosmonauts Sergei Zaletin and Alexander Kalery have found at least one air leak in the Mir Space Station after two weeks of tests on board the Russian laboratory.

Although ground crews are checking to see if additional leaks still could exist on Mir, the preliminary data show that they may have stopped the air from escaping the station.

“We have found something and time will show if this is the one we have been looking for,” said Yuri Grigoriev, deputy designer general of Energia.

Meanwhile, the crew is proceeding with planned pressure checks inside the module.