NASA said on Thursday that the leak caused a minor reduction in cabin pressure on the ISS.
Flight controllers determined there was no immediate danger to the crew overnight, but the crew as soon as they awoke.
So for now it looks like the Expedition 56 crew are probably safe, although flight controllers are continuing to monitor the pressure, just in case something does go wrong. The crew was never in danger, according to NASA.
The ISS crew reports that the leak originated from a hole measuring only about 2mm across located on the upper section of the Soyuz MS-09 spacecraft.
"This leak seems to have resulted from a micrometeoroid impact".
The former astronaut Chris Hadfield took to Twitter to explain how such issues are typically dealt with, using durable "Kapton" tape and a sealant called epoxy.
Astronauts on board the International Space Station have managed to fix a tiny tear in the fabric of a Russian capsule that was letting oxygen leak into space.
Rogozin said the leak could be repaired from within, with no need for a spacewalk. Earlier, flight controllers tapped into the oxygen supply of a Russian cargo capsule to partially replenish the atmosphere in the station.
There are five astronauts now stationed on the ISS: three Americans, two Russians and one German. The capsule will also have to bring them back home in December.
A Nasa spokesman said it was too early to speculate on whether the three might have to return to Earth early if the leak can not be stopped. NASA signed an accord in 2017 to acquire extra Soyuz seats into 2019, even though no further contracts involving the Russian craft have been announced.
Both natural micrometeoroids (bits of rock left over from the formation of our solar system) and space debris (small pieces of spacecraft that still orbit Earth) are travelling at incredible speeds through space.