Astronauts at the International Space Station (ISS) will attempt to fix the craft's broken cooling system during a series of three spacewalks in the coming days, NASA has announced.
The agency said it would delay a cargo resupplying mission until after the spacewalks, which are scheduled from Dec. 21 to Dec. 25, the agency announced Tuesday.
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The cooling system began experiencing problems last week, when it shut down in response to low temperatures. Officials warned at the time that a spacewalk might be necessary to fix it.
The plan is for NASA astronauts Rick Mastracchio and Mike Hopkins to remove a pump with a failed valve and replace it with a spare that is currently stored on an "external stowage platform," the agency said.
"The pump is associated with one of the station's two external cooling loops, which circulate ammonia outside the station to keep both internal and external equipment cool," NASA said in its announcement.
Judd Frieling, lead flight director of the current ISS expedition, describes the problem in more detail in this video.

The Orbital Sciences' Cygnus spacecraft resupply mission will be delayed until "no earlier than mid-January," NASA said. The agency will provide more details about the spacewalks Wednesday at a preview briefing from NASA's Johnson Space Center in Houston.
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Image: NASA
BONUS: 20 Epic Space Photos From Astronaut Chris Hadfield
"Antipodes Islands, looking like an island flag."
Image courtesy of Chris Hadfield
"Istanbul, Turkey at night, historic vital crossroads, clear as can be."
Image courtesy of Chris Hadfield
"Morning in NYC. Downtown Manhattan casts quite a shadow."
Image courtesy of Chris Hadfield
"I, for one, appreciate a healthy moustache, like this one inching along over New Zealand."
Image courtesy of Chris Hadfield
"Fogo, Cape Verde - a volcano so big it peaks above the Atlantic. Last active 18 years ago."
Image courtesy of Chris Hadfield
"A island off the Pacific coast of Mexico spins clouds into swirls of lace."
Image courtesy of Chris Hadfield
"While looking for the approaching Soyuz, I caught a glimpse of another orbiting body in the distance."
Image courtesy of Chris Hadfield
"An angry thunderstorm stands out against infinity."
Image courtesy of Chris Hadfield
"A gyre frozen into the ice, Newfoundland, Canada."
Image courtesy of Chris Hadfield
"Some of the things we build for ourselves are puzzlingly visible from space. Such as the islands of Dubai."
Image courtesy of Chris Hadfield
"Homs, Syria. Currently enveloped in fighting - an uncertain future layered upon a storied past."
Image courtesy of Chris Hadfield
"The Earth's fault lines are especially visible from orbit, like this one in South Africa."
Image courtesy of Chris Hadfield
"Soyuz departing - Oleg, Kev & Evgeni passing underneath Space Station on their way home after 5 months."
Image courtesy of Chris Hadfield
Commander Hadfield had only one comment for this photo: "!"
Image courtesy of Chris Hadfield
"Kolkata (Calcutta), India. 14 million of us living closely together on the Hooghly River in a huge developed wetland."
Image courtesy of Chris Hadfield
"Like a Praying Mantis, Canadarm2 poised to reach out and grab Dragon."
Image courtesy of Chris Hadfield
"Pyongyang, North Korea. A shrouded city of much global concern. In stark contrast with the South, not too far away."
Image courtesy of Chris Hadfield
"Air and pepper oil suspended in a water blob. I blew on it to make it wiggle."
Image courtesy of Chris Hadfield
"A rare space sight. Most borders are invisible from orbit. This one between Egypt and Israel isn't."
Image courtesy of Chris Hadfield
"Undoubtedly one of the coolest space sights on Earth, the Richat Structure of Mauritania."
Image courtesy of Chris Hadfield