Coolant
Coolant was a substance, usually liquid or gas, used for lowering the temperature of a system or a piece of a machine. 

In 2266, the intermix chamber aboard the  had primary manifolds which conducted coolant. That year, as the Enterprise successfully broke free of the tractor beam of an alien pilot vessel, the intermix chamber superheated with the  coolant temperature rising to two thousand s above maximum. ()

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Propulsion technology
Technology