Also, for the first time, all reaction wheels were in operation.

The problem had cropped up in one of the craft's reaction wheels.

The reaction wheels are flywheels, like those found in a clutch.

Over time reaction wheels may build up stored momentum that needs to be cancelled.

Designers therefore supplement reaction wheel systems with other attitude control mechanisms.

For this reason, reaction wheels are often used to aim spacecraft with cameras or telescopes.

Well designed Reaction wheels can provide a high actuating accuracy which do not depend on environmental effects.

A reaction wheel of similar capability would require megawatts of power.

The satellite was theorized to lose attitude control when its reaction wheels became saturated.

Attitude control was achieved using the hydrazine thrusters and four reaction wheels.

Reaction wheels work around a nominal zero rotation speed.

The craft is 3-axis stabilised with two star sensors, gyros and four reaction wheels.

To control satellite orientation, several magnetorquer coils and reaction wheels were added.

Reaction wheels are devices which aim a spacecraft in different directions without firing rockets or jets.

Block II spacecraft were 3-axis stabilized, with ground pointing using reaction wheels.

The main advantage over using active stabilization with propellants, gyroscopes or reaction wheels is the low use of power and resources.

Combined with reaction wheels, any desired maneuver can be performed as long as the formation's center of mass is not required to change.

Four reaction wheels (arranged so that any three can provide complete three-axis control) were used for normal attitude control.

Reaction wheels are usually implemented as special electric motors, mounted along the x, y and z axes.

In 2004, during the mission of the Hayabusa spacecraft, an X-axis reaction wheel failed.

It is 3-axis body stabilised using Sun and Earth sensors, momentum and reaction wheels.

Accordingly, many spacecraft utilize reaction wheels or control moment gyroscopes to control orientation in space.

Hayabusa also used solar pressure as a method of attitude control to compensate for broken reaction wheels and chemical thruster.

Therefore, in 2012, the mission was extended to 2016, but this would only be possible if all remaining reaction wheels (used for pointing the spacecraft) stayed healthy.

Another method for achieving three-axis stabilization is to use electrically-powered reaction wheels, also called momentum wheels.