How direction of satellite changes

[lalu]

how the direction of artifical satellites are changing in outer space by controlling from earth? how the reaction force is created at space without any medium .

 

[Bandersnatch]

Hi lalu,

Do you mean changing orientation(aka attitude control)?
It's mostly either by tiny rockets(RCS, or Reaction Control System), which use the principle of conservation of momentum, or by flywheels - a solar-powered electric engine spins a whell in one direction, and the spacecraft rotates in the othe, according to the conservation of angular momentum.

http://en.wikipedia.org/wiki/Reaction_control_system
http://en.wikipedia.org/wiki/Reaction_wheel
http://en.wikipedia.org/wiki/Attitude_control

 

[D H]

We've had this question arise a number of times here. It springs from a mistaken concept that rockets need something to push against. In this view, rockets launch because the exhaust pushes against the ground and thus forces the rocket to accelerate upward. This is a mistaken concept of how rockets work.

Rockets don't need something to push against. In fact, ground effects make rockets less efficient. Rockets work better when they are far away from the ground, and better yet when they are completely out of the atmosphere.

Rockets work because of conservation of linear momentum and angular momentum. The rocket exhaust going away from the rocket has some amount of linear momentum and angular momentum. The conservation laws dictate that the rocket's linear and angular momentum must change to match whatever is carried away.

 

[cenzi]

Hi lalu,

Do you mean changing orientation(aka attitude control)?
It's mostly either by tiny rockets(RCS, or Reaction Control System), which use the principle of conservation of momentum, or by flywheels - a solar-powered electric engine spins a whell in one direction, and the spacecraft rotates in the othe, according to the conservation of angular momentum.

http://en.wikipedia.org/wiki/Reaction_control_system
http://en.wikipedia.org/wiki/Reaction_wheel
http://en.wikipedia.org/wiki/Attitude_control

I personally prefer mini rokets. Interesting to know. Actually there are lots of propultion techs.

 

[pmacias]

I can explain the process of how the direction of artificial satellites changes in outer space and the role of controlling from Earth in this change. The direction of a satellite is controlled by its thrusters, which are small rocket engines that can be fired in different directions to change the satellite's velocity and therefore its direction. These thrusters are controlled by commands sent from Earth to the satellite's onboard computer.

The control of a satellite's direction from Earth involves a complex system of communication and data processing. Signals are sent from Earth to the satellite via radio waves, and the satellite's computer interprets these signals to determine the desired direction and amount of thrust needed. The computer then activates the appropriate thrusters to achieve the desired change in direction.

One may wonder how the reaction force is created in space without any medium for the thrusters to push against. This is where Newton's third law of motion comes into play. According to this law, for every action, there is an equal and opposite reaction. In the case of a satellite, the thrusters expel a high-velocity stream of gases in one direction, creating a reaction force in the opposite direction, which results in a change in the satellite's direction.

In the vacuum of space, there is no medium for the thrusters' exhaust gases to push against, so the reaction force is created solely by the expulsion of these gases at high speeds. This is similar to how a rocket works, where the exhaust gases are expelled out of the bottom of the rocket, creating a reaction force that propels the rocket upwards.

In summary, the direction of artificial satellites is controlled by thrusters, which are commanded from Earth via radio signals. The reaction force that allows for the change in direction is created by the expulsion of gases from the thrusters, in accordance with Newton's third law of motion.