That spacecraft could be ready to fly without people aboard sometime in February, a few weeks before the crew is due to return in March, officials said.
The crew who would fly home on the rescue ship would include NASA astronaut Frank Rubio and two cosmonauts, Sergey Prokopyev and Dmitri Petelin, who arrived at the station in September.
On December 14, as two cosmonauts prepared to leave the station for a spacewalk, ground controllers at Roscosmos and NASA discovered a coolant leak controllably pouring from the Soyuz capsule.
Roscosmos quickly canceled the spacewalk. And after inspecting the craft with the station’s robotic arm, they found the leak came from an external cooling line used to keep the capsule at a comfortable temperature as it transported crews through the atmosphere and into the vacuum of space transported.
In a statement last week, NASA said that “none of the crew members aboard the station were in danger and all were conducting normal operations throughout the day.” It added: “Images and data are analyzed by Roscosmos. The agency also closely monitors Soyuz spacecraft temperatures, which remain within acceptable limits. NASA and Roscosmos continue to work together on a course of action following ongoing analysis.”
None of the coolants contaminated the space station, said NASA space station chief Joel Montalbano, and astronauts on the station continue to conduct science experiments, including growing tomatoes.
It is not clear what caused the leak. Montalbano said possible causes being investigated include failure of the vehicle’s hardware or possible damage from a piece of debris or a micrometeorite.
On Wednesday, NASA canceled a spacewalk to install an improved solar array because debris was expected to come within a quarter mile of the station. Crews maneuvered the station to avoid the debris and the spacewalk was pushed back to Thursday.