A control momentum gyroscope, abbreviated to CMG was a type of highly sensitive gyroscope utilized in starship gyrocomputers. CMGs consisted of a spinning rotor, mounted to one or more tilting gimbals and placed inside a frame that was fixed parallel to the starship's "horizontal" position relative to a planet's terrain. When the starship changed position in either of its axis, the gyroscope would maintain the same plane and tilt, changing its angular momentum and causing a gyroscopic torque. Data from the CMGs' movement was then fed to specialized sensors in the gyrocomputer's exterior to assist the main navigation computer's function.