“I will tell you, there is no immediate need for the crew to come home today, that all the systems are operating,” Mr. Montalbano said.

During the news conference on Wednesday, Sergei Krikalev, executive director of the human spaceflight programs for Roscosmos, said the astronauts would try to remain on the station. In case of a leak, for example, they could close hatches to minimize the leak. But in some situations, the risk of returning in a damaged Soyuz would be lower than the risk of not leaving.

“The Soyuz is not good for nominal re-entry,” Mr. Krikalev said, “but in case of emergency, with extra risk, we are going to use this Soyuz.”

Mr. Montalbano said there had been discussions with SpaceX to see whether, for an emergency evacuation, it would be possible for one of the Soyuz crew to travel back to Earth in the Crew Dragon.

Mr. Krikalev said an investigation concluded that the damage was caused by a micrometeoroid about one millimeter in diameter that was traveling about seven kilometers a second, or more than 15,000 miles per hour. The micrometeoroid hit a radiator on the Soyuz, causing the coolant leak.

The location of the leak, at the end of the Soyuz farthest from the docking port, made it essentially impossible to attempt a repair in space. “You need not only to repair a hole but also to fill the radiator with a liquid, with a coolant,” Mr. Krikalev said. “And the procedure is so difficult and so risky that much less risk would be to just replace the vehicle.”

Mr. Krikalev said that based on the direction and speed, it could not have been a piece of orbital debris from a rocket part or some other human-made object. The question was prompted in part by a Russian antisatellite weapon test in November 2021 that created a debris cloud in orbit, which posed a risk to the space station.