It was used as a coolant to remove heat from the electrical systems on the orbiter engines.

CNN: Four compounds from shuttle can harm on contact

The ammonia coolant for the power channel, one of eight used to supply electricity to the station, would likely have run out by late Friday morning had it not been shut down, NASA said.

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The ammonia coolant for the power channel, one of eight used to supply electricity to the station, is likely to run out by late Friday morning and it will be shut down, NASA said.

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