"Fire in the hole" is an expression indicating that an explosive detonation in a confined space is imminent. It originated from American

miners A miner is a person who extracts ore, coal, chalk, clay, or other minerals from the earth through mining. There are two senses in which the term is used. In its narrowest sense, a miner is someone who works at the rock face; cutting, blasting, ...

, who needed to warn their fellows that a

charge Charge or charged may refer to: Arts, entertainment, and media Films * ''Charge, Zero Emissions/Maximum Speed'', a 2011 documentary Music * ''Charge'' (David Ford album) * ''Charge'' (Machel Montano album) * ''Charge!!'', an album by The Aqua ...

had been set. The phrase appears in this sense in American state mining regulations, in military and corporate procedures, and in various mining and military blasting-related print books and narratives, e.g., during

bomb disposal Bomb disposal is an explosives engineering profession using the process by which hazardous Explosive device, explosive devices are rendered safe. ''Bomb disposal'' is an all-encompassing term to describe the separate, but interrelated functi ...

or throwing

grenade A grenade is an explosive weapon typically thrown by hand (also called hand grenade), but can also refer to a shell (explosive projectile) shot from the muzzle of a rifle (as a rifle grenade) or a grenade launcher. A modern hand grenade genera ...

s into a confined space. In common parlance it has become a

catchphrase A catchphrase (alternatively spelled catch phrase) is a phrase or expression recognized by its repeated utterance. Such phrases often originate in popular culture and in the arts, and typically spread through word of mouth and a variety of mass ...

for a warning of the type "Watch out!" or "Heads up!".

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

has used the term to describe a means of staging a

multistage rocket A multistage rocket or step rocket is a launch vehicle that uses two or more rocket ''stages'', each of which contains its own engines and propellant. A ''tandem'' or ''serial'' stage is mounted on top of another stage; a ''parallel'' stage i ...

vehicle by igniting the upper stage simultaneously with the ejection of the lower stage, without a usual delay of several seconds. On the

Apollo 5 Apollo 5 (launched January 22, 1968), also known as AS-204, was the uncrewed first flight of the Apollo Lunar Module (LM) that would later carry astronauts to the surface of the Moon. The Saturn IB rocket bearing the LM lifted off from C ...

unmanned flight test of the first

Apollo Lunar Module The Apollo Lunar Module (LM ), originally designated the Lunar Excursion Module (LEM), was the lunar lander spacecraft that was flown between lunar orbit and the Moon's surface during the United States' Apollo program. It was the first crewed ...

, a "fire in the hole test" used this procedure to simulate a lunar landing abort.

Gene Kranz Eugene Francis "Gene" Kranz (born August 17, 1933) is an American aerospace engineer who served as NASA's second Chief Flight Director, directing missions of the Mercury, Gemini and Apollo programs, including the first lunar landing mission, Apo ...

describes the test in his autobiography:

References

{{DEFAULTSORT:Fire in the hole English phrases Explosion protection