How can jet purpoltion work in space?

Question

Since there is no air in Space, how can a jet create the force to push an object forward?

Answer 1

Newtons 3rd law: every acton has an equal and opposite reaction. The energy is puching away from the ship, which in turn pushes the ship forward.

Answer 2

Its amazing how many people think that rockets work by "pushing" against something like the air.
Rockets don't work that way.

Newton's 3rd law says that for every action there is an equal and opposite reaction. So when the exhaust of a rocket goes out the back, the rocket goes forward. So in space they work just fine because they don't have to push against air to work.

Answer 3

To simplify the previous answers, it is not the jet pushing against air that moves the vehicle forward, it is the "jet" virtually pushing against the craft that moves it forward.

Another way of putting it, the rocket "throws" exhaust backwards. By doing this, the rocket is pushed forwards.

Here's an experiment you can try in your mind. Imagine you are balancing on a narrow fence, facing to one side. Throw a ball as hard as you can. Very likely, this will cause you to fall backwards. It is not air resistance that causes this. It is the thrust you impart to the ball in one direction that makes you fall in the other direction.

Answer 4

Jet Propulsion cannot work in space (Jets breathe air, have combustion inside of them, and a huge blast of exhaust gases.

Rocket Propulsion, however, uses canned fuel and oxidizers which when mixed together produce a violent and focused combustion, and the exhaust gases flow out of a nozzle in the desired direction. No outside air is necessary.

Thrust is produced by the the exhaust gas shooting out of the nozzle. "For all reactions (Exhaust Gas thrust) there is an equal and opposite reaction (forward propulsion)." It is not necessary to have air to push against.

To prove this concept... Stand on a child's skate board or in a child's wagon holding a cinder block. Now throw the cinder block off the back of the skate board, or off the back of the wagon. Your effort to throw the cinder block will push the skate board or wagon forward with roughly the same force you used in trying to throw the cinder block...not counting friction losses.

Answer 5

Propulsion is not achived by having the jet push against air, but by having the pressure inside the engine push the front of the engine, a pressure that is not balanced in the rear, where that gas escapes.

If air was needed to be "pushed against", then the pressue would have somehow to "trace back" to the ship through the jet plume.

Answer 6

A "jet" cannot, since there is no air to mix with the fuel and cause combustion.

Rockets do, because they either use oxygen as part of the fuel, or use chemicals that ignite when mixed. The thrust from the exhaust pushes against the rocket, and moves it in the opposite direction from the thrust.

Answer 7

Hi,

If you had gas on board, heated it and thrust it out the back of the engine, the effect would be forward motion. Think the same as a rocket blasting off, not like an airplane engine.

Hope that helps,
Matt

Answer 8

Imagine a container (a perfect sphere, for simplicity's sake) that has gas under pressure inside it. The gas is pushing at all walls (sides? arcs? whatever) equally (hence equlibrium).

Now imagine a section of one wall disappearing. the wall opposite is experiencing a push that is not balanced. the container will move in that direction. That is the principle of the rocket.