The Russian space agency is preparing to launch a mission on Friday for two astronauts and one American astronaut who are aboard the International Space Station without a designated shuttle to get home.
The spacecraft that brought the three crew members to the ISS in the fall later developed a leak in its radiator cooling loop, forcing officials from both countries to come up with a new plan to return the trio to Earth.
Here is a brief overview of what has happened so far.
In December, a Russian spacecraft had a coolant leak
NASA astronaut Frank Rubio and Roscosmos cosmonauts Sergey Prokopev and Dmitry Petelin arrived at the International Space Station in September aboard a Russian Soyuz MS-22 spacecraft that remained on the space station.
On Dec. 14, as Prokopev and Petelin were preparing for their scheduled spaceflight, MS-22 was found to have an external coolant leak, NASA said.
After investigating the leak, Roscosmos engineers determined that the craft would not be viable for a normal return mission. It will still be available in the event of an emergency evacuation from the space station.
A Roscosmos official suggested that the leak may have occurred when a small meteorite hit the ship’s radiator. It Keeper reports.
Russian and US space officials began working on an alternative scheme to return the three crew members to Earth.
A separate leak marred the first attempt
The new plan would have launched an unmanned Soyuz MS-23 spacecraft to the ISS on February 19, giving the astronaut and two astronauts a functional craft to fly home.
But that plan was soon shelved after another coolant leak was discovered in a separate ISS spacecraft.
A Russian unmanned cargo ship called Progress 82, docked at the space station, experienced an unexplained pressurization of a coolant loop on February 11.
The leak on Progress 82 was unrelated to the planned rescue mission, but it prompted engineers at the Russian Mission Control Center near Moscow to investigate why the cargo ship lost coolant and delay the launch of MS-23.
Russian officials confirmed the mission this week
Soyuz MS-23 is now scheduled to launch on Friday.
Roscosmos announced on Monday that the state commission had given permission to launch a replacement ship, Russian state news agency TASS reported.
The spacecraft will carry approximately 948 pounds of cargo, including food and equipment for experiments, to the space station. Then Rubio, Prokopev and Petelin will fly home on MS-23 in a few months. They were originally supposed to leave at the end of March, but NASA said in January that their mission will now last until September.
The Russian state commission also decided to return the damaged ship MS-22 to Earth without a crew, TASS reported.