The leak from the Progress MS-21 cargo ship was spotted on February 11 and followed a similar leak from a Soyuz crew capsule in December.
Russian space officials said that December’s leak was caused by a tiny meteoroid that left a small hole in the exterior radiator and sent coolant spewing into space.
The new leak from another ship raised doubts about that theory, and Roscosmos investigated the incident to check whether it could have resulted from a manufacturing defect.
On Tuesday, Roscosmos shwoed shot of the Progress MS-21 showing a 12 mm hole in its external radiator, which it said hadn’t been spotted before.
Following checks at Russian space factories and launch facilities and a close inspection of the cargo ship before it was dumped, Roscosmos concluded that the latest leak resulted from an “external impact” similar to the one that caused December’s leak from the Soyuz crew capsule.