International Space station crew use tea leaves to find elusive air leak
- Cosmonaut found leak by releasing tea leaves to float freely in the station’s Russian side
- He saw them cluster near a crack on the wall, which was then patched with tape

The International Space Station has been leaking an unusual amount of air since September 2019.
At first, crew members held off on troubleshooting the issue, since the leak wasn’t major. But in August, the leak rate increased, prompting astronauts and cosmonauts on board the orbiting laboratory to start trying to locate its source in earnest.
Roscosmos, Russia’s space agency, announced on Thursday that crew members had finally pinpointed the leak’s location after devising an unusual test: They let tea leaves guide their search.
Cosmonaut Anatoly Ivanishin released a few leaves from a tea bag in the transfer chamber of the Zvezda Service Module – the section of the station’s Russian segment that houses a kitchen, sleeping quarters, and bathroom. Then the crew sealed the chamber off by closing its hatches, and monitored the tea leaves on video cameras as they floated in microgravity.
The leaves slowly floated toward a scratch in the wall near the module’s communication equipment – evidence that it was a crack through which air was escaping.
The crew has since patched the leak using Kapton tape, Roscosmos reported on Monday.