In spaceflight

Spaceflight

Spaceflight is the act of travelling into or through outer space. Spaceflight can occur with spacecraft which may, or may not, have humans on board. Examples of human spaceflight include the Russian Soyuz program, the U.S. Space shuttle program, as well as the ongoing International Space Station...

, the attitude control system (ACS) or attitude determination and control (ADAC) system of a spacecraft

Spacecraft

A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....

 consists of equipment to measure, report and change the orientation of the vehicle.

Components

Some components of the attitude control system include:

• Momentum wheel
  Momentum wheel
  A reaction wheel is a type of flywheel used primarily by spacecraft for attitude control without using fuel for rockets or other reaction devices....
  
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• Reaction wheels
• Control moment gyroscope
  Control moment gyroscope
  A control momentum gyroscope is an attitude control device generally used in spacecraft attitude control systems. A CMG consists of a spinning rotor and one or more motorized gimbals that tilt the rotor’s angular momentum. As the rotor tilts, the changing angular momentum causes a gyroscopic...
  
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• Reaction control system
  Reaction control system
  A reaction control system is a subsystem of a spacecraft whose purpose is attitude control and steering by the use of thrusters. An RCS system is capable of providing small amounts of thrust in any desired direction or combination of directions. An RCS is also capable of providing torque to allow...
  
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Attitude sensors such as gyroscope

Gyroscope

A gyroscope is a device for measuring or maintaining orientation, based on the principles of angular momentum. In essence, a mechanical gyroscope is a spinning wheel or disk whose axle is free to take any orientation...

s, rate gyro

Rate gyro

A rate gyro is a type of gyroscope, which rather than indicating direction, indicates the rate of change of angle with time. If a gyro has only one gimbal ring, with consequently only two planes of freedom, it can be adapted for use as a rate gyro to measure a rate of angular movement.Rate gyros...

s (in spacecraft this is called Astrionics

Astrionics

Astrionics is the science and technology of the development and application of electronic systems, sub-systems, and components used in spacecraft. The electronic systems on board a spacecraft include attitude determination and control, communications, command and telemetry, and computer systems...

)

Dynamics

The ACS causes torque

Torque

Torque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....

s, which spin the spacecraft. With an accurate model of the dynamics of the spacecraft, those torques can be used to control the spacecraft's attitude.

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