The space station sprung a leak. NASA and Russia just revealed why.

A puncture from a speeding micrometeoroid smaller than a sharpened pencil tip has rendered a Russian spaceship at the International Space Station unfit to fly crew home, including one NASA astronaut, Russia said Wednesday.

The Russian space agency Roscosmos will instead send a new ride up to the space station on Feb. 20 for the three crew members to come back to Earth. It doesn't seem that return flight will happen anytime soon, though.

Astronaut Frank Rubio and cosmonauts Sergey Prolopyev and Dmitri Petelin used a Russian spacecraft, a Soyuz MS-22, to get to the space station in September 2022. But just prior to a planned spacewalk on Dec. 14, the space agencies' ground crews noticed the capsule attached to the station was leaking coolant. The seepage was spotted on live video cameras.

Meanwhile, inside the spaceship's cabin, temperatures rose into the mid-80 degrees Fahrenheit.

"We think that Soyuz will return back safely," Sergei Krikalev, Roscosmos' head of human spaceflights, told reporters on a call. "The problem is that in small volume, humidity can be high, and crew may overheat with high temperature and high humidity."

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After an investigation, Roscosmos and NASA determined a fast micrometeoroid — a millimeter-wide speck of rock, not human-made space junk — must have struck an external radiator. They plan to bring back the leaky spaceship without passengers and send a new one, a Soyuz MS-23, to replace it next month. The replacement will carry supplies to the low-Earth orbiting laboratory but fly without additional crew.

The three men were originally supposed to come home in March. The change of plans will keep them at the station longer, though it's not clear by how much. The incident also will delay a new crew rotation.

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If an emergency happened at the station, a SpaceX capsule is also docked there. NASA is in talks with the company about how the crew could potentially use it if astronauts had to immediately evacuate.

Joel Montalbano, NASA's space station program manager, said the crew have taken the news well, are excited to be doing research in space, and are prepared to stay a full year if they must.

"I may have to fly some more ice cream to reward them," he said.