Sublimation
Sublimation is the process by which a solid becomes a gas without passing through a liquid state.

In 2259, when attempting to save the Delebs of Persephone III from a cometary impact, the Federation shuttlecraft  was transformed into a heating element that could  up a portion of the solid surface of comet C/2260-Quentin's nucleus and turned this portion into a gas which could then act as a propulsive force altering the comet's course away from the planet. ()

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Chemistry