Story highlights The ammonia is leaking from a cooling loop on a solar array

Crew tried to fix a leak in the same system in November

NASA says there is no danger to the space station crew

Three crew members are scheduled to end their mission on Monday

Crew members aboard the International Space Station are awaiting word on how to deal with leaking ammonia from an outside cooling system, NASA said Thursday in a news release

The six-man crew is not in danger, NASA said.

The space station crew reported seeing small white flakes floating away from the station, the space agency said. NASA helped locate the leak with external cameras while the crew used hand-held cameras pointed out windows.

The leak was in a cooling loop in a solar array that has leaked before. NASA said crew members tried to fix the leak in November. It is unclear whether this is the same leak or a new one.

The cooling system could shut down within 24 hours, it said. It is devising a plan to reroute other sources of power so that all systems remain fully operational.

Ammonia is used to cool each of the solar arrays that provide electricity to station systems, NASA said.

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Three crew members -- commander Chris Hadfield of Canada, NASA astronaut Tom Marshburn and Russian cosmonaut Roman Romanenko -- are scheduled to leave the station on Monday at 7:08 p.m. ET.

Hadfield asked NASA if the leak will affect the undocking. Capsule Communicator Doug Wheelock said officials at the Mission Control Center in Houston don't see anything that they can't overcome technically, but they would have more information in the morning.

Three crew members, NASA astronaut Chris Cassidy and Russian counterparts Alexander Misurkin and Pavel Vinogradov, will remain on the space station when the others leave.

They will be joined at the end of the month by three new crew members -- NASA astronaut Karen Nyberg, Russian cosmonaut Fiyodor Yurchikhin and European Space Agency astronaut Luca Parmitano, who are due to launch aboard a Russian Soyuz spacecraft on May 28.

The space station is operating normally aside from the leak, NASA said.