In this post I would like to show how rocket propulsion is impossible in the vacuum of space. In order to understand this concept we must first understand what nasa has to say about how rockets work in space. The following is an article on the subject of rocket principles from nasa's web site. I will address the article in depth blow the article. Or you can go read it from their website linked here. https://spaceflightsystems.grc.nasa.gov/education/rocket/TRCRocket/rocket_principles.html
Rocket Principles
A rocket in its simplest form is a chamber enclosing a gas under pressure. A small opening at one end of the chamber allows the gas to escape, and in doing so provides a thrust that propels the rocket in the opposite direction. A good example of this is a balloon. Air inside a balloon is compressed by the balloon's rubber walls. The air pushes back so that the inward and outward pressing forces are balanced. When the nozzle is released, air escapes through it and the balloon is propelled in the opposite direction.
When we think of rockets, we rarely think of balloons. Instead, our attention is drawn to the giant vehicles that carry satellites into orbit and spacecraft to the Moon and planets. Nevertheless, there is a strong similarity between the two. The only significant difference is the way the pressurized gas is produced. With space rockets, the gas is produced by burning propellants that can be solid or liquid in form or a combination of the two.
One of the interesting facts about the historical development of rockets is that while rockets and rocket-powered devices have been in use for more than two thousand years, it has been only in the last three hundred years that rocket experimenters have had a scientific basis for understanding how they work.
The science of rocketry began with the publishing of a book in 1687 by the great English scientist Sir Isaac Newton. His book, entitled Philosophiae Naturalis Principia Mathematica, described physical principles in nature. Today, Newton's work is usually just called the Principia. In the Principia, Newton stated three important scientific principles that govern the motion of all objects, whether on Earth or in space. Knowing these principles, now called Newton's Laws of Motion, rocketeers have been able to construct the modern giant rockets of the 20th century such as the Saturn V and the Space Shuttle. Here now, in simple form, are Newton's Laws of Motion.
Objects at rest will stay at rest and objects in motion will stay in motion in a straight line unless acted upon by an unbalanced force.
Force is equal to mass times acceleration.
For every action there is always an opposite and equal reaction.
As will be explained shortly, all three laws are really simple statements of how things move. But with them, precise determinations of rocket performance can be made.
Newton's First Law
This law of motion is just an obvious statement of fact, but to know what it means, it is necessary to understand the terms rest, motion, and unbalanced force.
Rest and motion can be thought of as being opposite to each other. Rest is the state of an object when it is not changing position in relation to its surroundings. If you are sitting still in a chair, you can be said to be at rest. This term, however, is relative. Your chair may actually be one of many seats on a speeding airplane. The important thing to remember here is that you are not moving in relation to your immediate surroundings. If rest were defined as a total absence of motion, it would not exist in nature. Even if you were sitting in your chair at home, you would still be moving, because your chair is actually sitting on the surface of a spinning planet that is orbiting a star. The star is moving through a rotating galaxy that is, itself, moving through the universe. While sitting "still," you are, in fact, traveling at a speed of hundreds of kilometers per second.
Motion is also a relative term. All matter in the universe is moving all the time, but in the first law, motion here means changing position in relation to surroundings. A ball is at rest if it is sitting on the ground. The ball is in motion if it is rolling. A rolling ball changes its position in relation to its surroundings. When you are sitting on a chair in an airplane, you are at rest, but if you get up and walk down the aisle, you are in motion. A rocket blasting off the launch pad changes from a state of rest to a state of motion.
The third term important to understanding this law is unbalanced force. If you hold a ball in your hand and keep it still, the ball is at rest. All the time the ball is held there though, it is being acted upon by forces. The force of gravity is trying to pull the ball downward, while at the same time your hand is pushing against the ball to hold it up. The forces acting on the ball are balanced. Let the ball go, or move your hand upward, and the forces become unbalanced. The ball then changes from a state of rest to a state of motion.
In rocket flight, forces become balanced and unbalanced all the time. A rocket on the launch pad is balanced. The surface of the pad pushes the rocket up while gravity tries to pull it down. As the engines are ignited, the thrust from the rocket unbalances the forces, and the rocket travels upward. Later, when the rocket runs out of fuel, it slows down, stops at the highest point of its flight, then falls back to Earth.
Objects in space also react to forces. A spacecraft moving through the solar system is in constant motion. The spacecraft will travel in a straight line if the forces on it are in balance. This happens only when the spacecraft is very far from any large gravity source such as Earth or the other planets and their moons. If the spacecraft comes near a large body in space, the gravity of that body will unbalance the forces and curve the path of the spacecraft. This happens, in particular, when a satellite is sent by a rocket on a path that is parallel to Earth's surface. If the rocket shoots the spacecraft fast enough, the spacecraft will orbit Earth. As long as another unbalanced force, such as friction with gas molecules in orbit or the firing of a rocket engine in the opposite direction from its movement, does not slow the spacecraft, it will orbit Earth forever.
Now that the three major terms of this first law have been explained, it is possible to restate this law. If an object, such as a rocket, is at rest, it takes an unbalanced force to make it move. If the object is already moving, it takes an unbalanced force, to stop it, change its direction from a straight line path, or alter its speed.
Newton's Third Law
For the time being, we will skip the second law and go directly to the third. This law states that every action has an equal and opposite reaction. If you have ever stepped off a small boat that has not been properly tied to a pier, you will know exactly what this law means.
A rocket can lift off from a launch pad only when it expels gas out of its engine. The rocket pushes on the gas, and the gas in turn pushes on the rocket. The whole process is very similar to riding a skateboard. Imagine that a skateboard and rider are in a state of rest (not moving). The rider jumps off the skateboard. In the third law, the jumping is called an action. The skateboard responds to that action by traveling some distance in the opposite direction. The skateboard's opposite motion is called a reaction. When the distance traveled by the rider and the skateboard are compared, it would appear that the skateboard has had a much greater reaction than the action of the rider. This is not the case. The reason the skateboard has traveled farther is that it has less mass than the rider. This concept will be better explained in a discussion of the second law.
With rockets, the action is the expelling of gas out of the engine. The reaction is the movement of the rocket in the opposite direction. To enable a rocket to lift off from the launch pad, the action, or thrust, from the engine must be greater than the mass of the rocket. In space, however, even tiny thrusts will cause the rocket to change direction.
One of the most commonly asked questions about rockets is how they can work in space where there is no air for them to push against. The answer to this question comes from the third law. Imagine the skateboard again. On the ground, the only part air plays in the motions of the rider and the skateboard is to slow them down. Moving through the air causes friction, or as scientists call it, drag. The surrounding air impedes the action-reaction.
As a result rockets actually work better in space than they do in air. As the exhaust gas leaves the rocket engine it must push away the surrounding air; this uses up some of the energy of the rocket. In space, the exhaust gases can escape freely.
Newton's Second Law
This law of motion is essentially a statement of a mathematical equation. The three parts of the equation are mass (m), acceleration (a), and force (f). Using letters to symbolize each part, the equation can be written as follows:
f = ma
By using simple algebra, we can also write the equation two other ways:
a = f/m
m = f/a
The first version of the equation is the one most commonly referred to when talking about Newton's second law. It reads: force equals mass times acceleration. To explain this law, we will use an old style cannon as an example.
When the cannon is fired, an explosion propels a cannon ball out the open end of the barrel. It flies a kilometer or two to its target. At the same time the cannon itself is pushed backward a meter or two. This is action and reaction at work (third law). The force acting on the cannon and the ball is the same. What happens to the cannon and the ball is determined by the second law. Look at the two equations below.
f = m(cannon) * a(cannon)
f = m(ball) * a(ball)
The first equation refers to the cannon and the second to the cannon ball. In the first equation, the mass is the cannon itself and the acceleration is the movement of the cannon. In the second equation the mass is the cannon ball and the acceleration is its movement. Because the force (exploding gun powder) is the same for the two equations, the equations can be combined and rewritten below.
m(cannon) * a(cannon) = m(ball) * a(ball)
In order to keep the two sides of the equations equal, the accelerations vary with mass. In other words, the cannon has a large mass and a small acceleration. The cannon ball has a small mass and a large acceleration.
Let's apply this principle to a rocket. Replace the mass of the cannon ball with the mass of the gases being ejected out of the rocket engine. Replace the mass of the cannon with the mass of the rocket moving in the other direction. Force is the pressure created by the controlled explosion taking place inside the rocket's engines. That pressure accelerates the gas one way and the rocket the other.
Some interesting things happen with rockets that don't happen with the cannon and ball in this example. With the cannon and cannon ball, the thrust lasts for just a moment. The thrust for the rocket continues as long as its engines are firing. Furthermore, the mass of the rocket changes during flight. Its mass is the sum of all its parts. Rocket parts includes engines, propellant tanks, payload, control system, and propellants. By far, the largest part of the rocket's mass is its propellants. But that amount constantly changes as the engines fire. That means that the rocket's mass gets smaller during flight. In order for the left side of our equation to remain in balance with the right side, acceleration of the rocket has to increase as its mass decreases. That is why a rocket starts off moving slowly and goes faster and faster as it climbs into space.
Newton's second law of motion is especiaily useful when designing efficient rockets. To enable a rocket to climb into low Earth orbit, it is necessary to achieve a speed, in excess of 28,000 km per hour. A speed of over 40,250 km per hour, called escape velocity, enables a rocket to leave Earth and travel out into deep space. Attaining space flight speeds requires the rocket engine to achieve the greatest action force possible in the shortest time. In other words, the engine must burn a large mass of fuel and push the resulting gas out of the engine as rapidly as possible. Ways of doing this will be described in the next chapter, practical rocketry..
Newton's second law of motion can be restated in the following way: the greater the mass of rocket fuel burned, and the faster the gas produced can escape the engine, the greater the thrust of the rocket.
Putting Newton's Laws of Motion Together
An unbalanced force must be exerted for a rocket to lift off from a launch pad or for a craft in space to change speed or direction (first law). The amount of thrust (force) produced by a rocket engine will be determined by the mass of rocket fuel that is burned and how fast the gas escapes the rocket (second law). The reaction, or motion, of the rocket is equal to and in the opposite direction of the action, or thrust, from the engine (third law).
That is the end of the article. To sum it up, nasa basically says that a rocket is pushed along by the thrust of the rocket gasses pushing back against the rocket body at the nozzle. " The rocket pushes on the gas, and the gas in turn pushes on the rocket." Nasa even says that rockets work better in space because the gases can escape freely.
So now let us delve into some problems with nasa's explanation.
1 Let us look at this paragraph from the above article first, "One of the most commonly asked questions about rockets is how they can work in space where there is no air for them to push against. The answer to this question comes from the third law. Imagine the skateboard again. On the ground, the only part air plays in the motions of the rider and the skateboard is to slow them down. Moving through the air causes friction, or as scientists call it, drag. The surrounding air impedes the action-reaction." What they are saying here is that the air or atmosphere is creating drag on the rocket. That I suppose is why they design them to be aerodynamic, to try to decrease the drag felt on the rocket. So the rocket traveling at a high rate of speed is going to experience drag which will slow the rocket down. Then wouldn't the inverse be true? Wouldn't the gases exiting the nozzle at a high rate of speed create negative drag (thrust) against the same air or atmosphere thus speeding the rocket up? Nasa says this next, "As a result rockets actually work better in space than they do in air. As the exhaust gas leaves the rocket engine it must push away the surrounding air; this uses up some of the energy of the rocket. In space, the exhaust gases can escape freely." Nasa actually admits here that the thrust is indeed pushing the air away but that it is wasting rocket energy by doing so. They are actually saying here that rockets will go faster with no atmosphere.
2 Lets look at the phrase "In space, the exhaust gases can escape freely." Too freely I would say. There are several videos showing people igniting model rocket engines in a vacuum chamber trying to prove that a rocket can work in the vacuum of space. The problem with that is getting a big enough chamber to do a decent experiment is almost impossible. The amount of pressures on a chamber, that don't even come close to the vacuum of space, are frighteningly strong even on the smallest chambers. In this video
at the 4 minute mark he says the engine he used normally has an 8 second burn, yet it burned completely in one second. His chamber didn't even come close to the true vacuum of space. Imagine if it was though, free expansion. The gases in a rocket would be sucked out instantaneously in the vacuum of space. Also the rocket in his chamber pushed off of the walls and the back of the chamber, you can see the burn marks on the back of the chamber at 4:36 of his video. Not to mention the gases the rocket produced in the relatively small chamber.3 Ok lets talk about Newton's 2nd law. Here nasa uses a canon as an example. Lets list the components of the canon. The canon, the canon ball, and the explosion. The explosion resides between the canon and the canon ball. The explosion exerts the same energy on each of them but the canon ball is smaller and weighs less than the canon so it travels further. Easy enough, until nasa applies it to a rocket. Look at this paragraph from the article regarding this, "Let's apply this principle to a rocket. Replace the mass of the cannon ball with the mass of the gases being ejected out of the rocket engine. Replace the mass of the cannon with the mass of the rocket moving in the other direction. Force is the pressure created by the controlled explosion taking place inside the rocket's engines. That pressure accelerates the gas one way and the rocket the other." They aren't replacing anything, they want to replace the canon ball with a longer explosion but in essence they are just eliminating the canon ball altogether. Where is the other mass for the explosion to exert equal forces to? Nasa wants you to believe this is a good analogy and that the gases push on the rocket without pushing off of something else like with the canon. But it is pushing off of something, the air or atmosphere, remember nasa admits this in the article above and I point that out in point number one, "As the exhaust gas leaves the rocket engine it must push away the surrounding air". We'll cover more on this later.
4 Escape velocity. Nasa says the escape velocity to reach orbit is approximately 25,000 MPH. That is 7 miles a second. Let that sink in. Can a rocket go faster than the speed that the propellent is exiting the nozzle? For the best chemical rockets, the exhaust speed is around 3,000 meters per second (1.8 miles per second). When you factor in the weight of the rocket it would be moving much slower. The math doesn't add up.
5 Nasa likes to use skateboards in their examples to how rockets work but is it a good comparison? If you stand on a skateboard and trust away a bowling ball from you it will propel you in the opposite direction. But where does the energy come from to trust the bowling ball in the first place? The skateboard is on wheels and the wheels are on the ground or earth. So if you are standing on the skateboard you are connected to the earth. The energy you use to thrust away the bowling ball comes from your connection the the ground. Try this, stand on the same skateboard and move the bowling ball away from you but don't let it go, what will happen? The exhaust gases are the same, they are connected to the rocket. The rocket and the exhaust gases are one mass. In the canon example there are three masses, the cannon, the explosion, and the cannon ball. The cannon is very heavy and robust, usually made of heavy steel. Why? So the separate mass of the explosion won't destroy it. Same with the canon ball, solid steel so it can survive the same explosion. If the rocket and the gases were two separate masses the rocket would not survive the massive forces from the gases that would be applied to the rocket. A rocket is not built like a cannon. It needs to be as light as possible. All the forces would be on the nozzles of the rocket. Have you seen how the nozzles dance around when ignited? Not to mention all the components that make up the nozzle. The Saturn 5 produced 7.6 million pounds of thrust. Do you think the nozzles on the Saturn 5 could withstand that kind of pressure? The Falcon Heavy produced 5.5 million pounds of thrust. How was the rocket in this test video, being strapped down, not crushed like a grape under that kind of pressure?
You can't have it both ways. Either the thrust is pushing the rocket directly or the thrust is pushing off of the air. This rocket booster would have to be infinitely more robust than a cannon to withstand those kind of pressures. More on this in point 6.6 So if the rocket is one mass and the gases are another where is the third mass. In the example of the cannon there are three masses, the cannon, cannonball and the explosion that sends the other two masses apart. In their example from the article here,
"In order to keep the two sides of the equations equal, the accelerations vary with mass. In other words, the cannon has a large mass and a small acceleration. The cannon ball has a small mass and a large acceleration.
Let's apply this principle to a rocket. Replace the mass of the cannon ball with the mass of the gases being ejected out of the rocket engine. Replace the mass of the cannon with the mass of the rocket moving in the other direction. Force is the pressure created by the controlled explosion taking place inside the rocket's engines. That pressure accelerates the gas one way and the rocket the other."
they eliminate the cannonball altogether. They try to replace the cannonball with the mass of gases which is absurd. What they are doing is leaving out the other mass which is the air or atmosphere. A cannon is a very poor example of how a rocket works. They have it reversed, the rocket and the mass of gases are one mass and replace the cannonball (smaller mass) and the atmosphere becomes the cannon (larger mass). The analogy doesn't work all that well because the cannon has three masses and the rocket has two. Another reason it fails is because the cannonball is always decelerating to its destination and the rocket is accelerating to its destination. The better example is actually the balloon. But nasa still gets that wrong.
7 No escape velocity. So if a rocket depends upon the atmosphere to push against there is no chance to make it into space since there is no atmosphere in space. The higher you go the less air the less thrust. A rocket can't go any higher than the highest recorded jet plane and even some of those numbers are inflated, but thats another post.
8 Weight in space? How much does a 200 pound man weigh in space. How much does a 6 million pound rocket (saturn V) weigh in space? The same? How do you calculate fuel for weightless objects. But that doesn't really matter since thrust, be it compressed air, nitrogen blasts, rocket gases, or any other mode of conventional propulsion, can not work in the vacuum of space the way nasa says it does.
Kinda sheds a new light on the phrase "It's not rocket science". I think most people have a hard time with this because of the ramifications. No satellites in orbit(weather balloons), no moon landings, no mars rovers, no space station, etc. That means everything we now have, all the tech we are using, is accomplished with in atmosphere technology. How much would our cell and cable bills actually be? Nasa is spending a mere fraction of the money they get on faking it.