Literally, any operation that cannot tolerate intervention, compromise or shutdown during the performance of its critical function. Mission critical environments usually support health, safety, security and human welfare. These environments also monitor, store, support and communicate data that cannot be lost or corrupted without compromising their core function. Since all computer and communications systems are highly sensitive to static electricity, static events pose an internal threat to mission-critical operations, such as flight control towers, energy management operations, 911 centers, command centers, dispatch, control rooms, data storage centers, hospitals, stock exchanges, laboratories, university research facilities, computer rooms—any space where the loss or corruption of data cannot be tolerated. Conductive flooring is a mandatory element in mission critical environments, because it prevents and discharges static electricity before it becomes a problem.

A server that runs an application that is crucial to get work done. If the server goes down, the company production crashes

The term mission critical (or mission-critical) refers to any factor (equipment, process, procedure, software, etc.) which is crucial to the successful completion of an entire project. It may also refer to a project the success of which is vital to the mission of the organization which attempts it.

Mission Critical is an adventure game released in 1995 by Legend Entertainment. Though its main advertising point was the presence of Star Trek: The Next Generation actor Michael Dorn, he played a very small role in the game.