External Tank Engine Heater

external tank
A Space Shuttle External Tank (ET) is the component of the Space Shuttle launch vehicle that contains the liquid hydrogen fuel and liquid oxygen oxidizer. During lift-off and ascent it supplies the fuel and oxidizer under pressure to the three space shuttle main engines (SSME) in the orbiter.

engine
A railroad locomotive
locomotive: a wheeled vehicle consisting of a self-propelled engine that is used to draw trains along railway tracks
A machine with moving parts that converts power into motion
motor that converts thermal energy to mechanical work
something used to achieve a purpose; "an engine of change"
A thing that is the agent or instrument of a particular process

heater
A person or thing that heats, in particular a device for warming the air or water
A conductor used for indirect heating of the cathode of a thermionic tube
A fastball
device that heats water or supplies warmth to a room
fastball: (baseball) a pitch thrown with maximum velocity; "he swung late on the fastball"; "he showed batters nothing but smoke"
A heater is object that emits heat or causes another body to achieve a higher temperature. In a household or domestic setting, heaters are usually appliances whose purpose is to generate heating (i.e. warmth). Heaters exists for all states of matter, including solids, liquids and gases.