Ablator

Part of speech: noun

Pronunciation: /æˈbleɪt.ɚ/

Definitions

1. A substance engineered to absorb and manage heat during atmospheric entry while simultaneously providing protective layers for vehicles
2. A specially formulated material that melts or vaporizes to shield spacecraft from high-temperature conditions during re-entry
3. A material designed to wear away by heat exposure to shield underlying surfaces from intense temperatures

Etymology: The word is a child of the space age. "Ablate" was borrowed into English from Latin "ablatus", the past participle of "auferre", meaning "to carry away," and it reached science as a term for material that is worn away by heat or erosion. The noun "ablator," formed by adding the agent suffix "-or" to that verb, names the substance that does the wearing away on purpose. The idea is the reverse of most heat protection. A heat shield that merely resisted high temperatures would have to absorb the energy of a returning capsule, and that energy becomes enormous at re-entry speeds. An ablator instead sacrifices itself: as it melts, chars, or vaporizes, it carries heat away with the lost material, leaving the spacecraft structure cool underneath.