Does Rocketry Work beyond Earth's atmosphere?

If NASA faked the moon landings, does the agency have any credibility at all? Was the Space Shuttle program also a hoax? Is the International Space Station another one? Do not dismiss these hypotheses offhand. Check out our wider NASA research and make up your own mind about it all.
Boethius
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread post by Boethius »

simonshack wrote:
Imagine now the high pressure emitted by any rocket from its (always open) nozzle. As it enters the vacuum of outer space, the very same - almost explosively rapid - pressure equalization is bound to occur. The rocket will be emptied of all of its pressurized fuel in a flash - by the overwhelmingly superior power of the vacuum itself. No matter how powerful the rocket (propelled by any fuel known to man / and designed to perform in our atmosphere) - the very laws of physics will not allow it to ascend any further into the void of space. It will haplessly tumble back to Earth.

This insurmountable 'little problem' may have been understood back in the heydays of early rocket research - thus paving the way for the ridiculous NASA circus and its clowns to take over and explore exploit outer space ... financially.
Hello simon,

fyi gas enters a vacuum at about 2,000 m/s (depends on the gas of course). So, as you point out, you're not going to get much thrust in space out of the 12 meter nozzle of an F1 engine in a Saturn 5 rocket. A molecule of gas that enters the nozzle is off into space in thousandths of a second.
http://adsabs.harvard.edu/full/1953ZA.....33..251K

I've been thinking about the pressure issue regarding space travel. As it turns out boats, planes and rockets (in the atmosphere), the 3 miracle machines of the modern age, all count on air pressure.

Metal boats float because of buoyancy, the pressure of the water below the hull is greater than the air pressure inside.

Planes fly because of lift, the pressure under the wing is greater than above.

All rockets equations have a thrust component which measures the pressure of the expelled gas.

Take away pressure (e.g. in the vacuum of space) and none of these three machines will work. Taking away pressure is like dividing by 0 in a math proof. Once you do it your answers are invalid even if you follow all the rules the rest of the way.
Lazlo
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread post by Lazlo »

WEIRD FIND

Weird online mag. While the front page is funny/quirky, check out page two: the Siemens rocket advert.

https://www.google.com/search?q=siemens ... e&ie=UTF-8

It won't let me hot-link

Pick the link that says "GOVERNING Magazine March 2013"
Maat
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread post by Maat »

Lazlo wrote:WEIRD FIND

Weird online mag. While the front page is funny/quirky, check out page two: the Siemens rocket advert.

https://www.google.com/search?q=siemens ... e&ie=UTF-8

It won't let me hot-link

Pick the link that says "GOVERNING Magazine March 2013"
PDF: http://chcconnections.com/reports/GOV_M ... 5B1%5D.pdf

Screenshots:
moon-cover-Governing-mag.jpg
moon-cover-Governing-mag.jpg (85.19 KiB) Viewed 11987 times
SpaceX-Siemans-ad.jpg
SpaceX-Siemans-ad.jpg (126.44 KiB) Viewed 11987 times
:rolleyes:
Lazlo
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread post by Lazlo »

Thanks Maat!

That is just too weird! If they're not having us on I don't know what.

L.
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread post by simonshack »

*


SIEMENS - the experts in 'virtualization'
http://www.usa.siemens.com/industrial-p ... ivity.html

Lazlo, that was mighty interesting.

A few gems from the above-linked Siemens page:
"From the increasing use of virtualization to outside-in manufacturing principles, public and private sector organizations alike are finding new ways to innovate, grow and prosper."

"Turning virtual into real and skeptics into believers
Siemens is helping leading companies explore new places in new ways. The engineers at SpaceX knew that successfully launching a rocket was contingent on millions of things going right. Just a single error could impact the entire mission to the International Space Station. To help solve this challenge, they turned to Siemens industry software. This played a critical role in enabling the SpaceX team to design and test products virtually before constructing them physically — optimizing the chances of a successful launch."
So I guess that "virtualization" is the name of the game - the 'keyword' to the phony space industry. <_<

******
ps: I have added an addendum to my above post.
CitronBleu
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread post by CitronBleu »

simonshack wrote:Addendum

Adding to the above-mentioned 'little problem', is the fact that rockets do indeed push against our relatively dense atmosphere (see the above 0,001 figure). Naturally, NASA will tell you otherwise - and this is one of their most infamous lies. They will repeat ad nauseam that their rockets' forward motion is due solely to Newton's laws - and that aerodynamics have nothing do with it. This is of course absurd and is akin to say that water has nothing to do with a rowing boat's forward motion. You need not be a genius to understand that it is the oars pushing the water backwards that make a rowing boat move forwards. If you raise the oars out of the water (density 1) and just flap the oars in the air (density 0,001), you won't go very far. Likewise, a rocket that works fine in our atmosphere (density 0,001) will obviously not go very far once the atmospheric density drops to 0,000000000000000000000001 !
Hi simon,

I am still confused about this topic. On one side I understand that movement is a result of something pressing against something else, as in the example you provided of oars moving against water, and on the other I can grasp the concept of an object seemingly pushing against itself without the contact of a dense medium, such as if I moved backward in a small boat after throwing a large object off the stern.

So which one is right? Or are they both right?
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread post by simonshack »

CitronBleu wrote: Hi simon,

I am still confused about this topic. On one side I understand that movement is a result of something pressing against something else, as in the example you provided of oars moving against water, and on the other I can grasp the concept of an object seemingly pushing against itself without the contact of a dense medium, such as if I moved backward in a small boat after throwing a large object off the stern.

So which one is right? Or are they both right?
Think "efficiency". How efficient would it be to (1) throw a large object off the stern of a boat - versus (2) making one single oar thrust? I would say - on the top of my head - that (1) would make the boat move for about 30cm. Whereas (2) would make the boat move by 300cm - or 3m.

Think about it: the two human actions (1)throwing large object off the stern of the boat /vs (2) oar thrust - would produce more or less the same joules. Yet, the 1st would make the boat go forward 30cm - while the 2nd would make the boat go forward 300cm.
Boethius
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread post by Boethius »

simonshack wrote:*

Addendum

Adding to the above-mentioned 'little problem', is the fact that rockets do indeed push against our relatively dense atmosphere (see the above 0,001 figure). Naturally, NASA will tell you otherwise - and this is one of their most infamous lies. They will repeat ad nauseam that their rockets' forward motion is due solely to Newton's laws - and that aerodynamics have nothing do with it. This is of course absurd and is akin to say that water has nothing to do with a rowing boat's forward motion. You need not be a genius to understand that it is the oars pushing the water backwards that make a rowing boat move forwards. If you raise the oars out of the water (density 1) and just flap the oars in the air (density 0,001), you won't go very far. Likewise, a rocket that works fine in our atmosphere (density 0,001) will obviously not go very far once the atmospheric density drops to 0,000000000000000000000001 !
Rockets have to push against (or pull on) something. Just like everything else that moves.

A rocket pushing itself through the vacuum of space, totally isolated, touching nothing, being touched by nothing, is a fantasy born of hope and dreams, ignoring fundamental results in chemistry and physics.
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread post by Heiwa »

Boethius wrote:
simonshack wrote:*

Addendum

Adding to the above-mentioned 'little problem', is the fact that rockets do indeed push against our relatively dense atmosphere (see the above 0,001 figure). Naturally, NASA will tell you otherwise - and this is one of their most infamous lies. They will repeat ad nauseam that their rockets' forward motion is due solely to Newton's laws - and that aerodynamics have nothing do with it. This is of course absurd and is akin to say that water has nothing to do with a rowing boat's forward motion. You need not be a genius to understand that it is the oars pushing the water backwards that make a rowing boat move forwards. If you raise the oars out of the water (density 1) and just flap the oars in the air (density 0,001), you won't go very far. Likewise, a rocket that works fine in our atmosphere (density 0,001) will obviously not go very far once the atmospheric density drops to 0,000000000000000000000001 !
Rockets have to push against (or pull on) something. Just like everything else that moves.

A rocket pushing itself through the vacuum of space, totally isolated, touching nothing, being touched by nothing, is a fantasy born of hope and dreams, ignoring fundamental results in chemistry and physics.
Ships push against water that produces plenty friction that slows the ships down. The force driving the ship is produced by its engine, e.g. driving a propeller.
Rockets in space/vacuum luckily push against nothing so no friction will slow the rocket down. The force applied to a rocket is produced by its engine ejecting plenty hot gases into the space (pollution). As there is no friction in space, the rocket will accelerate as long as the force is applied. Evidently rocket engines work in space as the combustion takes place inside the rocket engine where there is no vacuum. :rolleyes:
Flabbergasted
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread post by Flabbergasted »

Boethius wrote:Rockets have to push against (or pull on) something. Just like everything else that moves.

A rocket pushing itself through the vacuum of space, totally isolated, touching nothing, being touched by nothing, is a fantasy born of hope and dreams, ignoring fundamental results in chemistry and physics.
Bravo!

"An object seemingly pushing against itself" in the vacuum of space is no better than the story about Baron Münchhausen pulling himself and his horse out of the mud!

Image
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread post by simonshack »

Heiwa wrote: Rockets in space/vacuum luckily push against nothing so no friction will slow the rocket down. The force applied to a rocket is produced by its engine ejecting plenty hot gases into the space (pollution). As there is no friction in space, the rocket will accelerate as long as the force is applied.
Unfortunately, we have two problems here, Heiwa:

1- The "plenty hot gases" of the rockets would immediately be sucked out by the immensely superior force of the external vacuum.

2- With nothing to push against - and with the rocket's pressure now equalized with the external vacuum, there can be no acceleration at all. Only in NASA's fairy-tale physics would such a miracle take place ! <_<


That is, unless you are happy to buy the fanciful NASA-notion that "the rocket fuel pushes against itself".
Franz Kafka himself wouldn't have been able to come up with such bewildering nonsense.
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread post by Heiwa »

simonshack wrote:
Unfortunately, we have two problems here, Heiwa:

1- The "plenty hot gases" of the rockets would immediately be sucked out by the immensely superior force of the external vacuum.

2- With nothing to push against - and with the rocket's pressure now equalized with the external vacuum, there can be no acceleration at all. Only in NASA's fairy-tale physics would such a miracle take place ! <_<

1. Actually the hot gases just pushes against the rocket and propulses it forward. It is like a ship in water - the propeller thrust pushes the ship forward.
2. The beauty with vacuum or space is that there is no friction that stops movements of rockets produced by forces applied to them. In water friction and waves produced really prevent high speeds.
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread post by Maat »

I think Simon found the 'Master Key' by using NA$A's own claims (on page 11 ^_^):
simonshack wrote: ...
Anyhow, here are my two cents about rocket propulsion - a line of reasoning using NASA's own data. As you will notice, I am not even mentioning the question of vacuum - only of ever-decreasing air pressure with increasing altitudes - something I trust we can all agree about.

Image

Source of graphics used for above diagram:
http://en.wikipedia.org/wiki/Rocket_engine

NOTE : interesting tidbits from that Wiki article:
"Rockets become progressively more underexpanded as they gain altitude."

and...
"The shape of the plume varies from the design altitude, at high altitude all rockets are grossly under-expanded, and a quite small percentage of exhaust gases actually end up expanding forwards".


Thoughts and comments most welcome.
hoi.polloi
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread post by hoi.polloi »

It seems to me what we're saying here is:

Something like this won't produce a strong thrust without using an enormous amount of fuel, but because of the vacuum, the acceleration will not be hindered and so extremely high speeds can be reached that could not be reached on Earth. However, before one could build up to a speed or combat a vector one is already headed, one's fuel would be spent.

Rotation would be easier than changing course, but both of them would spend more fuel than could even be stored on board a vessel.

Hence, rocketry might be possible but it would be extremely wasteful, not pragmatic, and end quickly.
Boethius
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread post by Boethius »

Heiwa wrote:
simonshack wrote:
Unfortunately, we have two problems here, Heiwa:

1- The "plenty hot gases" of the rockets would immediately be sucked out by the immensely superior force of the external vacuum.

2- With nothing to push against - and with the rocket's pressure now equalized with the external vacuum, there can be no acceleration at all. Only in NASA's fairy-tale physics would such a miracle take place ! <_<

1. Actually the hot gases just pushes against the rocket and propulses it forward. It is like a ship in water - the propeller thrust pushes the ship forward.
A rocket is not like a ship in the water. Don't you see? A ship is in contact with the water while a rocket isn't in contact with anything.

Let's stop using false analogies like boats floating in water and people sitting on chairs throwing things and see if we can come up with a logical reason, or one based on physics, as to why a rocket, sitting on nothing, in contact with nothing will move when it presses against nothing.
Heiwa wrote: 2. The beauty with vacuum or space is that there is no friction that stops movements of rockets produced by forces applied to them. In water friction and waves produced really prevent high speeds.
Friction is the frenemy (friend + enemy). We need friction to start moving but then we want it to go away so we can keep moving. Space has no friction so we can't start moving in space (nor can we change direction, accelerate, etc...)
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