Gyroscope is a cylindrical mass which is mounted to spin rapidly about an axis. There are three major components, the spinning mass or rotor, the spin axis, gimbals which are used to mount the spin axis.

A gyroscope is a rotating body that exhibits two fundamental properties, rigidity and precession.

Rigidity in space refers to the principle that a gyroscope remains in a fixed position in the plane in which it is spinning. An example of rigidity in space is that of a bicycle wheel. As the bicycle wheels increase speed, they become more stable in their plane of rotation. This is why a bicycle is very unstable and very manoeuvrable at low speeds and very stable and less manoeuvrable at higher speeds.

Gyroscopic precession is the resultant action or deflection of a spinning object (gyro) when a force is applied to this object. This action occurs approximately 90° later in the direction of rotation from the point where the force is applied. This principle allows the gyro to determine a rate of turn by sensing the amount of pressure created by a change in direction.

A gyro which is rotating in space responds to forces being applied to it by an evasive movement at an angle of 90° to the force being applied.