Reaktiokykky

Reaktiokykky, also known as reaction wheels, are devices used in spacecraft to control their orientation and angular momentum without the need for external forces. They consist of a spinning wheel mounted on a gimbal, which can be accelerated or decelerated to change the spacecraft's rotation. By adjusting the speed of the wheels, the spacecraft can be oriented in any direction, making reaktiokykky essential for missions requiring precise pointing, such as astronomical observations or satellite communications.

Reaktiokykky have several advantages over other attitude control systems, such as thrusters. They are more efficient, as they do not require propellant, and they can provide continuous torque, which is useful for maintaining a stable orientation. However, they also have limitations. Reaction wheels can only control the spacecraft's rotation around a single axis, so multiple wheels are typically used to control all three axes. Additionally, they can experience a phenomenon known as "wheel saturation," where the wheels reach their maximum speed and can no longer provide torque, requiring a backup system to take over.

Reaktiokykky have been used in various spacecraft, including satellites, probes, and the International Space Station. They are a critical component of modern spacecraft design, enabling precise control and stability in the harsh environment of space.