Due to the age and designs which were used when it was constructed, the Internation Space Station is not as airtight as it should be. A small amount of air is lost on a daily basis, while careful monitoring ensures that astronauts are safe and leaks can be found.
A new leak has been detected, with two years having passed since the last one. The rate at which air is lost is too high to match the regular amount. Mission control observed an initial increase in air loss in September 2019, but the amount was minor.
For now, there is no risk for the current ISS crew, but the three astronauts will have to spend some time in the Zvezda Service Module in the following days, as experts will try to track down the source of the leak.
The hatches of the space station will be closed during the weekend, so mission control can track down the down the soiurce of the leak. There are no risks for the crew during the test, which should the module where the leak is more substantial. Once this is done, astronauts and mission control will inspect the module to find the precise cause.
Not the first
A previous leak was found two years ago, and the same procedures were followed as segments were sealed and examined. The leak came from a Soyuz spacecraft, which was attached to the Roosevelt module at that point in time. Air escaped through a two-millimeter hole that was sealed quickly.
It can be quite hard to track an air leak since there are several factors that may lead to air fluctuations inside the ISS. Astronauts will continue their normal duties while they stay in the Zvezda module, and it is estimated that the first results will be available by the end of the week.