Reaktiokiertoilla

Reaktiokiertoilla, also known as reaction wheels, are devices used in spacecraft to control and stabilize their orientation in space. They consist of a spinning wheel mounted on a fixed axis, which can change the spacecraft's angular momentum by altering the wheel's speed. This principle is based on the conservation of angular momentum, where the spacecraft's rotation is counteracted by the rotation of the wheel in the opposite direction.

Reaction wheels are typically used in conjunction with other attitude control systems, such as magnetorquers or thrusters, to provide precise and efficient orientation control. They are particularly useful for small to medium-sized spacecraft, where the use of thrusters alone would be impractical due to fuel consumption.

There are several types of reaction wheels, including momentum wheels, control moment gyroscopes, and reaction control wheels. Momentum wheels are used to store and release angular momentum, while control moment gyroscopes provide active control of the spacecraft's attitude. Reaction control wheels combine the functions of both momentum wheels and control moment gyroscopes.

Reaction wheels have several advantages, including high precision, low power consumption, and the ability to provide continuous attitude control. However, they also have some limitations, such as the potential for wheel saturation, where the wheel's angular momentum reaches its maximum limit, and the need for periodic desaturation to prevent this from occurring.

In recent years, there has been a growing interest in the use of reaction wheels for small satellites and CubeSats, due to their compact size and low mass. However, the development of new technologies, such as cold gas thrusters and microthrusters, is also contributing to the advancement of attitude control systems for small spacecraft.