Does Rocketry Work beyond Earth's atmosphere?

[Boethius]

A big problem with rockets in space continues to be
how does the gas expelled through the nozzle contribute any force to the system?
when:

1. Free Expansion says gas does no work entering the vacuum

2. The Laws of Gasses say gas can't exist in the vacuum

3. The Laws of Gasses say gas can't do any work in the vacuum

(note that 1., 2. and 3. above all agree with and support each other)

If the gas expelled from the ship in space produces no force how does the ship move?

First, there should be a theoretical reason why I am wrong/mistaken about how gasses work in the vacuum or how they are used by the ship.

Second, there should be reasonable experimental evidence that supports the above theory. Pictures of the Space Shuttle don't count.

Come on Rocketry Forum members / NASA supporters. Show me how I have been mistaken. Can you do this using science? Without strawmen and ad hominem arguments? Let's stick to gasses in the vacuum, please. That's where my doubts stem from.

Why I don't think anyone can answer me: In my opinion, space rocketry is unproven, unscientific conjecture. A fantasy world that has captured the imagination of many and led otherwise rational and intelligent persons to abandon logic and fall under its spell, which is pretty much the story of "advances in science" in the 20th century. Engineering has done pretty well for itself, but science seems to be going backwards.

[sceppy]

Space rockets, among other things, are , indeed fantasy, Boethius... and what you say, is correct and a lot of people know this, yet billions don't, because it's the classic magicians trick of people being employed to be the face of bull shit.
Any rational thinking, clear minded, unbiased person who has the ability to push aside peer pressure will know that a rocket can not kick itself up its own arse and fly into the sky, which is what they are being told to accept as gospel truth.

If only space rockets were really hot air balloons with a basket full of cannonballs around a man in a space suit, I could be more persuaded by the arguments that it works and goes higher because the space man is throwing cannon balls out of the basket, until his balloon folds up in no atmosphere that is.
It would be akin to seeing Wile E Coyote trying to light a match and blowing it back up as he's falling to his doom.

[Farcevalue]

A big problem with rockets in space continues to be
how does the gas expelled through the nozzle contribute any force to the system?
when:

1. Free Expansion says gas does no work entering the vacuum

2. The Laws of Gasses say gas can't exist in the vacuum

3. The Laws of Gasses say gas can't do any work in the vacuum

(note that 1., 2. and 3. above all agree with and support each other)

If the gas expelled from the ship in space produces no force how does the ship move?

First, there should be a theoretical reason why I am wrong/mistaken about how gasses work in the vacuum or how they are used by the ship.

Second, there should be reasonable experimental evidence that supports the above theory. Pictures of the Space Shuttle don't count.

Come on Rocketry Forum members / NASA supporters. Show me how I have been mistaken. Can you do this using science? Without strawmen and ad hominem arguments? Let's stick to gasses in the vacuum, please. That's where my doubts stem from.

Why I don't think anyone can answer me: In my opinion, space rocketry is unproven, unscientific conjecture. A fantasy world that has captured the imagination of many and led otherwise rational and intelligent persons to abandon logic and fall under its spell, which is pretty much the story of "advances in science" in the 20th century. Engineering has done pretty well for itself, but science seems to be going backwards.

Isn't the atmosphere made up of gases? Oxygen, Co2, Helium, etc. Why are these not sucked into the vacuum of space under the principles of free expansion?

[Boethius]

A big problem with rockets in space continues to be
how does the gas expelled through the nozzle contribute any force to the system?
when:

1. Free Expansion says gas does no work entering the vacuum

2. The Laws of Gasses say gas can't exist in the vacuum

3. The Laws of Gasses say gas can't do any work in the vacuum

(note that 1., 2. and 3. above all agree with and support each other)

If the gas expelled from the ship in space produces no force how does the ship move?

First, there should be a theoretical reason why I am wrong/mistaken about how gasses work in the vacuum or how they are used by the ship.

Second, there should be reasonable experimental evidence that supports the above theory. Pictures of the Space Shuttle don't count.

Come on Rocketry Forum members / NASA supporters. Show me how I have been mistaken. Can you do this using science? Without strawmen and ad hominem arguments? Let's stick to gasses in the vacuum, please. That's where my doubts stem from.

Why I don't think anyone can answer me: In my opinion, space rocketry is unproven, unscientific conjecture. A fantasy world that has captured the imagination of many and led otherwise rational and intelligent persons to abandon logic and fall under its spell, which is pretty much the story of "advances in science" in the 20th century. Engineering has done pretty well for itself, but science seems to be going backwards.

Isn't the atmosphere made up of gases? Oxygen, Co2, Helium, etc. Why are these not sucked into the vacuum of space under the principles of free expansion?

Gravity holds the atmosphere in place keeping the gasses (as well as you and me) from floating off into space.

[simonshack]

*


As of...

Newton's Third Law of Motion

"Consider the propulsion of a fish through the water. A fish uses its fins to push water backwards.
But a push on the water will only serve to accelerate the water. Since forces result from mutual interactions, the water must also be pushing the fish forwards, propelling the fish through the water."

http://www.physicsclassroom.com/Class/n ... /u2l4a.cfm

Therefore, in absence of water, air - or any other adequate reaction force...

AS BELOW - SO ABOVE


No Martini? No party!

[sceppy]

Absolutely spot on Simon.
It's one of the reasons why I tell people to understand what atmospheric pressure can do and how it works, because it's just a gaseous liquid like everything above us is.
People underestimate the meaning of atmospheric pressure at sea level of 14.7 psi and think it's nothing, because we walk in it and wave our arms and it doesn't crush us.
What they don't realise is, it doesn't crush us, because we equalise that pressure easily, because our bodies are essentially a denser liquid and also minerals applying the exact same pressure back...but we do suffer the effects of cell break down due to the pressure and it starts with our skin that we notice but it's a pressure on all cells in the body.

I hate being a simplistic genius but I can't help it.

Air molecules equalise the pressure inside our bodies as to what is outside and it's a case of earth's law of, every action has an equal and opposite reaction.
Newton may have thought it up but the truth is, it applies to "everything" on this earth no matter what.

By the way, gravity does not exist, it's simply air pressure acting on everything but that's another story.
To show how strong atmospheric pressure is, we only have to look at people climbing up buildings using vacuum clamps or window companies carrying huge panes of glass with window vacuum clamps.

People think they suck but it's atmospheric pressure trying to get inside the clamp to equalise the pressure that's inside it, which there is always a small amount of air inside the clamp, as a perfect vacuum cannot be created on earth.
Anyway this may get boring so I'll save that for another time if anyone would like to know all about it in another topic.

Basically, understanding of air pressure by those that believe it to be weak, will go a long way into them understanding how rockets and everything else works on this earth.

[arc300]

By the way, gravity does not exist, it's simply air pressure acting on everything but that's another story.

I've spent my whole life skirting around the edges of insanity, so I'm perfectly capable of entertaining all manner of seemingly contradictory notions. Just one example being the ongoing "The Cold of Space and Our Universe..." thread. If you're game to write more, I'll read it.

[hoi.polloi]

Please move gravity discussion to: http://cluesforum.info/viewtopic.php?f=23&t=1641

[simonshack]

*

Whereas we may conclude that no motion can be applied to a stationary rocket in a vacuum - this old NASA movie seems to 'prove' that humans do indeed get around when exposed to near-zero pressure !



From the Science Channel:

SPACESUIT TESTING
"The instantaneous effects on a human when exposed to near-vacuum conditions"


full link: http://www.youtube.com/watch?v=KO8L9tKR4CY

[I, Gestalta]

*

Whereas we may conclude that no motion can be applied to a stationary rocket in a vacuum - this old NASA movie seems to 'prove' that humans do indeed get around when exposed to near-zero pressure !

Well, I never!

How dare you besmirch the good and wholesome name of NASA with such carnal filth? MODS!

[Boethius]

*

Whereas we may conclude that no motion can be applied to a stationary rocket in a vacuum - this old NASA movie seems to 'prove' that humans do indeed get around when exposed to near-zero pressure !



From the Science Channel:

SPACESUIT TESTING
"The instantaneous effects on a human when exposed to near-vacuum conditions"


full link: http://www.youtube.com/watch?v=KO8L9tKR4CY

This OSHA report of a death in a vacuum chamber seems to disagree with the NASA video

Employee #1 went into a vacuum chamber testing area to look through the porthole opening in a pressurized vacuum chamber and observe the condition of a nose cone that was being tested. The 12 in. diameter glass in the porthole opening imploded, causing Employee #1's head and one arm to be pulled into the vacuum chamber. He died of crushing head injuries and asphyxia.

So, with the NASA vacuum chamber just open the door and run on in, no wait, no fuss, no problem. Also, there doesn't seem to be any indication of air flowing into the vacuum (re-pressurization), seen either in the technician's clothing or on the hose dangling off to the side. So what happened to the studies that say air flows into the vacuum at 2 km/s? (Note that because of free expansion this fast moving air doesn't create thrust).

With the GE chamber if there's a pressure failure and you're anywhere near the vacuum, you're dead. I tend to think that NASA is more likely to fake a vacuum chamber test than GE is to fake an employee death (Peter Lanza notwithstanding... )

Good call on the Ridiculum Absurdum Simon.

http://www.osha.gov/pls/imis/accidentse ... d=14321087

[Heiwa]

http://www.osha.gov/pls/imis/accidentse ... d=14321087

This is a very strange accident. Outside pressure is abt 1000 hP and inside the vacuum chamber on the other side of the the porthole is vacuum and pressure 0 hP as all or 99% of the air inside has been pumped out. Why the porthole suddenly implodes by being looked at, is not clear. The pressure difference is not big. The porthole should have been tested to manage 1000 kP.

We do not know the volume of the vacuum chamber, but if the port hole glass suddenly bursts the broken glass and external air are sucked into the vacuum chamber . Why a persons solid head attached to a body with arms resting against the chamber should be sucked in is not clear. It sounds like a fairy tale.

Anyway - it is clear that air doesn't like vacuum and fills it. Same with hot rocket engine gases inside a combustion chamber.

[simonshack]

^


"ROCKETS DO NOT PUSH AGAINST AIR (1)"

I would like to dedicate this post to those who still embrace the absurd notion that "rockets do not push against air", a trite NASA-promoted quackery - tediously parroted by their many 'apollogists'. As it is, it appears to be the most audacious and aggressively-guarded fallacy ever concocted - in order to uphold in our minds the very feasibility of (outer) space travel. Here it is proclaimed once again, this time in an 'educational' article from major space contractor Northrop Grumman:

Does the rocket push down on the surrounding air?
A common misconception regarding rockets is that they push against the air surrounding them. In fact, rockets work best [!] in a vacuum like outer space. There’s no air or atmosphere in a vacuum. Fortunately for us, we are surrounding by a breathable atmosphere. Unfortunately for the rocket, our atmosphere pushes against its movement upwards.
http://www.northropgrumman.com/Corporat ... _Guide.pdf

"Unfortunately for the rocket, our atmosphere pushes against its movement upwards".

Well, yes - dear Northrop Grumman 'educators'... : this is, in fact, what is commonly known as aerodynamic drag. It is air resistance exerted on the frontal area of the rocket - PUSHING against it. It is a force - and it increases exponentially with speed. And yes, this pesky force unfortunately slows the rocket's progress through the air. Luckily though, if a rocket is travelling at, say, 3000km/h in the atmosphere - this exponentially increasing air drag will always be far inferior to the formidable power of the rocket thrust (a massive "counter-drag", if you will) which undoubtedly PUSHES against the air below it - with a high-speed 'wall' of burning propellants ejected at 16.000km/h (4,4km/s).





To acknowledge the existence of air drag in front of the rocket while, at the same time, deny the existence of the opposite air displacement exerted by the exhaust plume below it - is an utter contradiction in terms and a crude offense to common sense. If this were to be true (that "rockets do not push against air"), this would mean that the formidable, explosive thrust of a rocket's exhaust plume does not encounter any air resistance - a preposterous and outlandish contention, if there ever was one. Instead, as the NASA quackery goes, we are asked to believe that rockets are propelled solely by the "recoil force" generated by the rapid expulsion of fuel mass from rocket tanks. If this were true, we should all hover above our toilet seats when stricken with explosive diarrhea - yet I doubt that anyone has ever had the (mixed) fortune of experiencing such a thrill.

To be sure, if one were to supply propellant to a tankless rocket from a container anchored on Earth (via a very, very long hose), the rocket would take off just as well - and indeed, much better and faster - given its considerably inferior weight. The truth is that, to uphold the idea that rockets can be niftily propelled in the vacuum of outer space, NASA's propaganda wizards have had no option but to hammer into our brains the absurd notion that rocket jets "do not push against air"! It is now time for this mainstay of NASA's hypnotic brainwashing machine to be flushed out of our skulls.

"Does not push against air" (NASA claims):

http://www.youtube.com/watch?v=uxgMhHOaUSY

[brianv]

Rockets work in the vacuum that is some people's minds. Remember the child's game leap-frog? You leap over your playmate by forcing down on him/her with your hands, NASA's rockets leap-frog into space by forcing down on themselves. Ridiculous.

[Maat]

Rockets work in the vacuum that is some people's minds. Remember the child's game leap-frog? You leap over your playmate by forcing down on him/her with your hands, NASA's rockets leap-frog into space by forcing down on themselves. Ridiculous.

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[For more looney toon physics comparisons: http://www4.ncsu.edu/~gsparson/Physics/forces.html]