NASA has temporarily halted all spacewalks due to a problem with spacesuits aboard the International Space Station, according to reports. space news† A helmet worn by an astronaut filled with a layer of water earlier this year.

The leak arose during the most recent spacewalk on March 23 by astronauts Raja Chari and Matthias Maurer. At the end of the nearly seven-hour flight, Maurer reported having water in his helmet.

Because it was a small layer of water, there was no immediate danger to it. But NASA is not reassuring. The space agency wants to solve the problem before making new spacewalks. Until then, allowances should only be used in emergencies.

Earlier this week, NASA said it had no idea how water got into the helmet. The space agency is currently investigating this. However, this is only possible when the suits are back on the ground. This is expected to happen in early June.

This isn’t the first time water has ended up in an astronaut’s helmet. This also happened to Luca Parmitano in 2013. The astronaut was not injured, but after walking, NASA said his eyesight and breathing were impaired. The space agency said earlier that Parmitano survived the accident at the time because he remained calm.