How do rockets fly in the vacuum of space!?

[Plastic Pilot]

Hi kind sires,

Just fund a video on youtube that was quickly deleted a few days ago about how all the space programs and rockets are a hoax. It explained how rockets can't fly in space by today's technology, like reaction engines, solid fuel, or thermonuclear technology.

I told my father whom is a chemical-biological engineer, and never saw the man with that expression on his face... just went blank for 5 seconds and then tried to figure out how it is possible for the fuel driven technology to produce and induce movement in perfect vacuum and total lack of gravity or other type of electromagnetic field....

The video is no more on youtube, but fund out some other material.


La la la la lie...

 

[Jakko]

There is no "total lack of gravity" in space, and certainly not of electromagnetic fields.

Rockets can fly in a vacuum for the same reason they (and jet engines) can fly in atmosphere: they push mass out the back of the engine. That means Newton's third law of motion ("every action has an opposite but equal reaction") applies: the mere fact of the engine pushing gas out the back, means the engine will be pushed forward.

The reason to use a rocket in space, rather than a jet engine, is because a rocket carries its own oxidiser and all of its reaction mass (namely, fuel plus oxidiser), while a jet engine sucks both oxidiser and most of its reaction mass in through the front (namely, air). Because there is no air in a vacuum, a jet engine naturally won't work there.

 

[Edbert]

chemical/biological =/= aerospace

(my dad worked at NASA from 1961 to 1974)

 

[Jim62]

The real problem is that darned radiation belt that surrounds the earth.

 

[blakeh1]

There is no "total lack of gravity" in space, and certainly not of electromagnetic fields.

Rockets can fly in a vacuum for the same reason they (and jet engines) can fly in atmosphere: they push mass out the back of the engine. That means Newton's third law of motion ("every action has an opposite but equal reaction") applies: the mere fact of the engine pushing gas out the back, means the engine will be pushed forward.

The reason to use a rocket in space, rather than a jet engine, is because a rocket carries its own oxidiser and all of its reaction mass (namely, fuel plus oxidiser), while a jet engine sucks both oxidiser and most of its reaction mass in through the front (namely, air). Because there is no air in a vacuum, a jet engine naturally won't work there.

^Yep,

and for that same reason, if an astronaut was to shoot a gun in space it would propel him backwards.

Also to add...if there was no gravity effects in space, nothing would keep planets in orbit, black holes would not exist, planets would have never formed etc..
Also once in motion, it will never slow theoretically slow down unless captured by a strong gravity field. Gravity assist is also how they "sling shot" things into the outer solar system without wasting as much fuel to boost instead

and interesting tidbit is "weightlessness" experienced by Astronauts is actually , more like a form of free-fall. They still have the same mass

 

[Belugawrx]

The real problem is that darned radiation belt that surrounds the earth.

The real problem is the junk we're leaving orbiting this ball...

 

[Plastic Pilot]

There is no "total lack of gravity" in space, and certainly not of electromagnetic fields.

Rockets can fly in a vacuum for the same reason they (and jet engines) can fly in atmosphere: they push mass out the back of the engine. That means Newton's third law of motion ("every action has an opposite but equal reaction") applies: the mere fact of the engine pushing gas out the back, means the engine will be pushed forward.

The reason to use a rocket in space, rather than a jet engine, is because a rocket carries its own oxidiser and all of its reaction mass (namely, fuel plus oxidiser), while a jet engine sucks both oxidiser and most of its reaction mass in through the front (namely, air). Because there is no air in a vacuum, a jet engine naturally won't work there.

What you say there is what the video was about, it stated that the particles that are gas particles that are expelled from the rocket's burner have nothing against what to push back, because they told us that space is perfect vacuum, so there is nothing. No particles of air, water or anything else.... just nothing to push against. If you want to explain to yourself and others that it is possible for a rocket to push it self against nothing, then I guess that is how they tricked us in believing the hoax that then can fly above the atmosphere.

Or in another case, they just lie to us and space is not vacuum and has some sort of atmosphere.

chemical/biological =/= aerospace

(my dad worked at NASA from 1961 to 1974)

Congrats to your dad for making part of a space program no one can confirm it is what they tell us it is, just lunch a bunch o "hi-tech" rockets things in the sky and some old Hollywood basement and some lights and cameras and off we go... Just mentioned that my father is an chemical engineer to point out that the man has knowledge about spotting some of the lies they make us believe on the TV.

 

[Plastic Pilot]

The real problem is that darned radiation belt that surrounds the earth.

https://science.nasa.gov/biological-physical/stories/van-allen-belts/

 

[JackCW]

There is no "total lack of gravity" in space, and certainly not of electromagnetic fields.

Rockets can fly in a vacuum for the same reason they (and jet engines) can fly in atmosphere: they push mass out the back of the engine. That means Newton's third law of motion ("every action has an opposite but equal reaction") applies: the mere fact of the engine pushing gas out the back, means the engine will be pushed forward.

The reason to use a rocket in space, rather than a jet engine, is because a rocket carries its own oxidiser and all of its reaction mass (namely, fuel plus oxidiser), while a jet engine sucks both oxidiser and most of its reaction mass in through the front (namely, air). Because there is no air in a vacuum, a jet engine naturally won't work there.

A vacuum in a lack of matter, not gravity. There is gravity in a vacuum.

 

[Rob]

I think someone has a vacuum in their head.

 

[Jakko]

nothing to push against.

If it helps you, think about it like this: The rocket pushes itself against its own exhaust gas.

Or think of it another way: guns. When a gun fires a bullet, the gun itself suffers recoil: it pushes back against the shooter's hands or shoulder. Where do you think this recoil comes from? It happens because the bullet and the propellant gases go forward, which result in the gun being pushed the other way.

Hell, go find a garden hose, connect it to the tap, and turn it on. You will feel the hose push back in your hand because of all the water coming out. This has nothing to do with the water pushing against the hose as such — the water flows through it, so if anything, it would pull the hose along with it. The reason the hose is pushed backwards is because of Newton's third law of motion: when the water comes out of the end, it results in the hose being moved the other way.

If you want to explain to yourself and others that it is possible for a rocket to push it self against nothing, then I guess that is how they tricked us in believing the hoax that then can fly above the atmosphere.

The hoax here is trying to make people believe a rocket can't work in a vacuum, and/or to make them believe that the atmosphere goes on indefinitely. Please don't say you believe in a flat earth, too.

 

[Calico Jack]

The Wright brothers probably never thought about flying in space where there was no air. They designed a propeller that pushed on the air to make their plane move forward. A rocket could have also moved the plane forward but rockets were not yet invented. Just what is the difference in a propeller and a rocket driven device. It is fairly common for people to have a misconception regarding the principle on which a rocket operates.

The force of friction propels ordinary objects such as cars and trains. The train pushes on the track and the car pushes on the road because of friction between the wheels and track or road. However, a rocket in space has nothing to push against. Therefore, the force of propulsion must be something other than friction. The rocket works because of the law of conservation of linear momentum.

The law of conservation of linear momentum is very important in physics. Momentum is defined as the mass of an object times its velocity. Simply stated the conservation law says that in a closed system (one without outside influences) the total momentum of the system remains constant. Now the momentum of various parts of the system may change, but the total momentum must always be constant.

Consider a machine gun mounted on a lightweight cart. If the gun is fired, the bullets go in one direction while the cart recoils in the other. The magnitude of the momentum of the bullets equals the momentum of the cart but the directions are opposite. Thus, one momentum is positive and one is negative, making the total change (their sum) zero. Although things are now moving, the total momentum of the gun-cart system has not changed.

In a similar manner, a rocket moves in space because the gases are given momentum as they are expelled by the rocket engine. Consider the rocket resting in space. There is no momentum in the system. Next, the engine ignites. As the exhaust gases go in one direction, the rocket goes in the other to keep the total momentum of the system constant. This momentum change of the gases gives the rocket the "push" to go forward. We call this push, the thrust of the rocket, i.e. the force exerted on the rocket.

This thrust depends upon the speed of the exhaust gases and the mass of gas being expelled each second, sometimes called the burn rate in pounds of fuel per second. On Earth, air tends to inhibit the exhaust gases getting out of the engine. This reduces the thrust. However, in space since there is no atmosphere, the exhaust gases can exit much easier and faster, thus increasing the thrust. Therefore, the rocket engine actually works better in space than here on Earth.

Credited: Union University Physics Dept.