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.

Re: Why Rocketry Doesn't Work in the Vacuum

Unread postby pov603 on Fri Jul 26, 2013 9:01 am

I'd posted this question on the Moon Hoax discussion [with an answer from Heiwa which I shall add shortly] and am still unsure as to why, if rockets are capable of leaving the Earth or entering high atmosphere/vacuum, more 'effective' and less cumbersome methods are not used by NA(one)SA(w).
Re: The Moon Hoax
by pov603 on 07 Jan 2013, 15:03

@Heiwa
This is one thing that has puzzled me regarding take off weight.
Why would they launch [any] rockets completely vertically, when even early V1 rockets were launched on sleds/ramps of a shallow angle?
Should that be bogus anyhow, even the BAe Harrier 'Jump Jet' started to be launched from the Aircraft carriers by use of a ramp when it became apparent that there would be a huge operational saving generated on fuel consumption rather than launching 'straight up'.


Re: The Moon Hoax
by Heiwa on 07 Jan 2013, 15:46

@pov603

According NASA/Apollo info the Apollo 11 space ship + rocket third stage was first sent into Earth orbit, i.e. up and then sideways, by the rocket first (with fins) stage and second stage (w/o fins) using plenty, plenty fuel and then ... after 1.5 orbit at 7 500 m/s speed and maybe 400 000 m altitude ... at the right moment - the third stage with Apollo 11 space ship on top was sent off direction Moon burning a lot of more fuel resulting in 11 200 m/s departure speed.
And then Apollo 11 and the empty of fuel third stage rocket separated and went on to the Moon slowed down by Earth gravity most of the way.
The empty third stage missed the Moon with a tight margin, while Apollo 11 had to slow down to get inte Moon orbit ... using 10-11 tons of fuel to reduce speed that was increasing at the end of trip due to Moon gravity pulling it along.

According my simple calculations maybe 40-50-60 tons of fuel was required to slow down ... and that's the first problem (as Apollo 11 didn' carry so much fuel). Asking NASA if it is possible to slow down a 32 ton space craft (ex fuel) from 2 400 to 1 500 m/s speed with a rocket engine using only 10-11 tons fuel results in no answer. So I made the popular web page. It seems NASA then informed their crazy friends at Apollohoax.net which in turn told me in their forum that I was a criminal idiot asking such questions insulting them. And there we are today. I was then banned at Apollohoax.net so I haven't got a clue what is happening there.
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread postby simonshack on Tue Aug 27, 2013 12:15 am

*

Ok, folks - let's get this rocket-power issue out of the way - once and for all !



ARE ROCKETS PROPELLED BY "RECOIL POWER" - as claimed by NASA?


You see, NASA claims that their rockets do NOT push against air ( "at all!") - and this is why they can also operate in the vacuum of space. They claim that their rockets are propelled by "recoil force" - the same force which a bullet exerts on a gun as it gets shot out from its muzzle. But would that force be strong enough to propel a huge, 760.000kg rocket up into the skies?

Here's how Wickedpedia can help us wrap our minds around this intriguing issue:

"A bullet fired from an M16 rifle has approx 1763 Joules of kinetic energy as it leaves the muzzle,
but the recoil energy exerted on the gun is less than 7 Joules."

http://en.wikipedia.org/wiki/Recoil

Right away, we see that the kinetic energy exerted on the rifle is 250 times less than the energy exerted on the bullet :

Weight of M16 RIFLE: 4kg
https://en.wikipedia.org/wiki/M16_rifle
Weight of M16 bullet: 3.6g http://www.defencetalk.com/forums/army- ... -a-4686-7/

Let us now build an imaginary, GIANT M16 ROCKET/RIFLE - and see how these energies would compare at a larger scale.
I will use a factor of 190.000 - which brings my standard M16 to the weight of a French "ARIANE 5" rocket (760.000kg):

Image

WEIGHT OF GIANT M16 ROCKET
: 4kgX 190.000 = 760.000kg

... whereas a to-scale M16 bullet will weigh:

WEIGHT OF GIANT M16 BULLETS:
3.6gX 190.000 = 684kg

This means that, if our GIANT M16 ROCKET could fire a steady flow of 3 giant bullets each second, it would expel a mass of 684 X 3 =2052kg per second - which is about the same fuel mass allegedly ejected by the ARIANE each second (2000kg) - as claimed by ESA / NASA.

If we now multiply (by our 190.000 factor) the known kinetic energy exerted on an M16 rifle by a bullet exiting its muzzle (about 7 joules) we get (7X190.000= 1.330.000 joules).

Well, 1.330.000 joules is about 1782 hp - slightly less than the horsepower of this special, 1800hp twin-turbo Chevrolet Camaro:

Image
http://www.lsxtv.com/news/video-1800-horsepower-twin-turbo-camaro-hits-the-dyno/

Let's imagine the power of three of these Camaros exiting the ARIANE rocket nozzle each second : would this be enough to make the French 760.000kg ARIANE ROCKET lift off from the launch pad?

Image

Probably yes. But only at sea level - and up to some 50/70 km altitude - until the air becomes so thin that the bullet-flow pressure (against the surrounding air's pressure) drops below the necessary force to sustain the rocket aloft - as it combats the force of gravity. In other words, all rockets will hit a physical boundary - beyond which they will stop ascending. Yes, this would mean that mankind has no means to exit the atmosphere - and that NASA has fooled us all, ever since its inception.


"Likewise, as elevation increases, there is less overlying atmospheric mass, so that atmospheric pressure decreases with increasing elevation. On average, a column of air one square centimeter in cross-section, measured from sea level to the top of the atmosphere, has a mass of about 1.03 kg and weight of about 10.1 N (2.28 lbf)."
Image
http://en.wikipedia.org/wiki/Atmospheric_pressure


When studying aeronautics and astronautics in the 1950s, Kármán calculated that above an altitude of roughly 100 km (62 mi), a vehicle would have to fly faster than orbital velocity to derive sufficient aerodynamic lift from the atmosphere to support itself. At this altitude, [100km]the air density is about 1/2200000 the density on the surface.
http://en.wikipedia.org/wiki/Kármán_line
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread postby CitronBleu on Tue Sep 03, 2013 1:57 pm

Even though I agree much of the rocket launch footage appears to be staged, I will have to agree with Heiwa that rockets can theoretically work in a vacuum.

By quoting the analogy of the energy produced by firing an M16 bullet, you are in fact validating the idea that a rocket can "push against its own fuel."

Newton's Law states that "for every action there is an equal and opposite reaction." This statement is expressed by the following formula:

M(1) x V(1) = M(2) x V(2)

Where M stands for mass and V stands for velocity.

We are using meters and Kg.

Let's calculate the recoil distance involved in firing an M16 rifle:

Weight of M16 = 4Kg; Weight of M16 bullet = 0.004Kg; velocity of M16 bullet = 950m/s

If we plug in the numbers:

4Kg x V(M16 rifle) = 0.004Kg x 950m/s

So using this formula the recoil, or the velocity of the M16 rifle going in the opposite direction to the bullet = (0.004Kgx950m/s)/4 = 0.95m/s

Thus the bullet is fired 950m/s in one direction, and the M16 rifle "travels" 1m/s in the opposite direction, which seems intuitively about right when considering rifle recoil.

Let's use the same formula to calculate the speed of Ariane 5 one second after lift-off (T=1):

Weight of Ariane 5= 760,000Kg; Fuel mass ejected = 3,925Kg/s; Average exhaust velocity (all 3 engines) =2,415.42m/s *

If I plug the numbers in the formula:

(760,000Kg-4,000) x V(Ariane 5 at T=1) = 4,000Kg/s x 2,400m/s

I get:

V(Ariane 5 at T=1) = 12.7m/s

The Ariane 5 is accelerating at 12.7m per second per second. This acceleration is larger than the effect of gravity (9.8m per second per second), so the rocket is indeed rising.

Just like if I attempt to run faster and faster, or paddle harder and harder, or if my free-moving M16 rifle fired a continuous and steady stream of bullets, my speed will continually increase, as my acceleration is cumulative.

Not only that, but my rocket acceleration will also increase over time as a result of the decrease in my total rocket mass due to fuel consumption:

Let's consider the weight of Ariane 5 at T=120 seconds, right before the two boosters are jettisoned.

M(Ariane 5 at T=120) = 760,000Kg - (120s x 4,000Kg/s) = 280,000Kg

At 120 seconds after launch, Ariane 5 will have total mass 280,000Kg.

Let's plug this mass in our initial formula M(rocket) x V(rocket) = M(Fuel) x V(fuel):

280,000Kg x V(Ariane 5 at T=120) = 4,000Kg/s x 2,400m/s

This gives us:

V(Ariane 5 at T=120) = 34.3 m/s

At time T = 120 seconds, Ariane 5 will be accelerating 34m every second, minus the effects due to gravity and air drag.

Now is the fuel exhaust velocity of the Ariane 5 correct? How does such a large rocket slowly rise and not tumble? I don't know, but on paper rockets can work in a vacuum.

* Data from https://campus.tum.de/tumonline/LV_TX.wbDisplayTerminDoc?pTerminDocNr=7357
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread postby simonshack on Tue Sep 03, 2013 4:04 pm

^
Dear Citronbleu,

Here's a short and simple question which I'd like to submit to ESA (if they actually do take questions, that is) - but maybe you can help me out and double-check my question's pertinence and validity, as I may well just be missing something :

°°°°°°°°°°°

Dear ESA,

According to the pdf linked below (describing the specs of the ARIANE 5 rocket), I read that the main stage of the rocket burns for 535 seconds (or almost 9 minutes):

"The main stage burns continuously for about 535s, and delivers the essential part of the kinetic
energy required to place the payloads into orbit."

http://www.astrium.eads.net/media/docum ... ht-191.pdf


I have also read that the Ariane 5 ejects 2000kg of propellant every second - and that each of the two boosters contains 240 tons solid propellant - for a total of 480tons. Now, since 480tons of propelllant ejected at a rate of 2000kg/s will only last for 4 minutes, what keeps the ARIANE 5 going for the remaining 5 minutes?

***********************

Again, Citronbleu, I may be missing something right now - but please let me know exactly what!
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread postby CitronBleu on Tue Sep 03, 2013 4:42 pm

simonshack wrote:^
Dear Citronbleu,

Here's a short and simple question which I'd like to submit to ESA (if they actually do take questions, that is) - but maybe you can help me out and double-check my question's pertinence and validity, as I may well just be missing something :

°°°°°°°°°°°

Dear ESA,

According to the pdf linked below (describing the specs of the ARIANE 5 rocket), I read that the main stage of the rocket burns for 535 seconds (or almost 9 minutes):

"The main stage burns continuously for about 535s, and delivers the essential part of the kinetic
energy required to place the payloads into orbit."

http://www.astrium.eads.net/media/docum ... ht-191.pdf


I have also read that the Ariane 5 ejects 2000kg of propellant every second - and that each of the two boosters contains 240 tons solid propellant - for a total of 480tons. Now, since 480tons of propelllant ejected at a rate of 2000kg/s will only last for 4 minutes, what keeps the ARIANE 5 going for the remaining 5 minutes?

***********************

Again, Citronbleu, I may be missing something right now - but please let me know exactly what!


Hi Simon,

Each solid-fuel booster ejects approximately 2,000kg of fuel per second. In the link I provided above in my previous post the exact figure is 1,835kg ejected every second by each booster, while at lift-off the main stage engine is ejecting its own liquid fuel at a rate of 255Kg per second.

The two boosters are said to only last a little over two minutes (120s x 4,000Kg = 480,000Kg), and provide 90% of the propulsion, at the end of which they are said to fall back to Earth and propulsion is provided by the main stage only. The numbers are right.
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread postby simonshack on Tue Sep 03, 2013 6:53 pm

CitronBleu wrote: The numbers are right.


Oh well, I guess that their numbers are 'right' and that, most likely, this part of the ongoing Space Scam would be well covered from a strictly technical perspective. I should probably (and ideally, all of us non-rocket scientists) stick to exposing the ridiculous imagery of these rocket launches which, technically speaking, are way below any acceptable / believable standard. The imagery seems to be the weakest point of the Grand Space Hoax - so let us (mere observers) keep pointing out this utterly laughable visual data.

I'm sorry but, at this point, NO technical 'evidence' of the feasibility of launching rockets in space - as advertised by NASA and ESA - can possibly convince me that their proposed rocket launches - and subsequent space explorations - are in any manner real / truthful / legit / authentic. Any number of people is of course free to believe that NASA and ESA do what they say they do - but just count me out of that number.
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread postby brianv on Tue Sep 03, 2013 9:47 pm

Hypothetical question!

Consider a handgun that is somehow floating in mid-air. Now imagine that same gun can be fired by remote control. The gun isn't being held, the trigger is not pulled, the ignition happens electronically. The gun has been cocked before being set adrift then fired remotely. Will the gun reload? Remember nobody is holding it!

Challenge:

If one of the vacuum rocket guys can build a working model of the rocket that pushes against itself

I will build one of the other type that uses propellant and gases that pushes against the earth and atmosphere
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread postby simonshack on Wed Feb 19, 2014 6:43 pm

Does a seagull fly without air?

Does a rocket fly without air?

Can a dolphin propel itself in the air?

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

Unread postby rusty on Thu Feb 20, 2014 8:54 pm

hoi.polloi wrote:Image


I'm not sure if this has been mentioned here or not - but there are actually toy "water rockets" out there which work quite well.

http://en.wikipedia.org/wiki/Water_rocket

Everyone can build one...and I suppose they'd actually work in a vacuum as well, because they rely on repulsion. Go figure.

The thing I haven't figured out yet: Is this design generally working better than a pure "pressurized air rocket", and if so, why? I mean, the energy put into pressurizing the air in the bottle should be the same regardless of the added water. Does this tell us something about the efficacy of "gas rockets" in general?
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread postby brianv on Thu Feb 20, 2014 9:56 pm

and I suppose they'd actually work in a vacuum as well, because they rely on repulsion


?
the old solid fool argument

That Professor Goddard[...] does not know the relation of action to reaction, and of the need to have something better than a vacuum against which to react -- to say that would be absurd. Of course he only seems to lack the knowledge ladled out daily in high schools.


—New York Times, 13 January 1920

http://en.wikipedia.org/wiki/Rocket
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread postby hoi.polloi on Fri Feb 21, 2014 3:32 am

Everyone can build one...and I suppose they'd actually work in a vacuum as well, because they rely on repulsion. Go figure.


Do you mean "go figure" as in you imply that the supposition you make must be true and no figuring is actually necessary? Or do you mean to say that we should actually all go figure it out using proper maths and figures? If the latter is true and you are not using the colloquial, I would encourage you to actually do the figuring yourself. I am satisfied that shooting water out of a rocket would not actually work as adequate propulsion for the activities said to be going on "in space" (i.e.; maintaining orientation, orbital corrections, launching satellites, etc.) until it is proven that:

1. a liquid as such could be adequately pressurized to carry plenty of days' worth of fuel without the rocket exploding in the vacuum of space
and
2. the entire system including the entire weight of all this fuel could actually reach the vacuum in the first place based on Earthly propulsion such as engines, jets and shooting flaming fuel out the butt

Sometimes we seem to forget that vacuum means total absence, the same rules may not apply, and said rules are extremely difficult and expensive to test for.
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread postby rusty on Fri Feb 21, 2014 11:21 am

Are you suggesting that not only exhaust gases can interact with the surrounding atmosphere, but also ejected liquids and solids? Do you entirely question the existence of the repulsion principle? That would be a new twist I'd need to go and figure out indeed.

Seriously, no one is suggesting that water/liquid/solid rockets could ever reach or surpass the boundaries of our atmosphere (if there is such a thing). Their design is too obviously limited to smaller applications (toys), at least in my understanding. Nevertheless, those toys do work and I can see no reason why this should not be based on repulsion. If it works in a vacuum (if there is such a thing) or not is, of course, purely speculative, but I currently can't think of a solid reason why it should not.

The thing that puzzles me is: Is this water rocket design really more effective than using a pure pressurized air rocket design and why? I mean, the contained energy is the same and the mass is by far greater.
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread postby Flabbergasted on Fri Feb 21, 2014 12:24 pm

rusty wrote:The thing that puzzles me is: Is this water rocket design really more effective than using a pure pressurized air rocket design and why? I mean, the contained energy is the same and the mass is by far greater.


Honestly, I don´t see the mystery here. A water rocket (or ANY rocket for that matter) pushes against a fixed surface (the ground) in order to lift off. If it were possible to launch a water rocket at an altitude of 100 m, it would push against the air alone (instead of primarily pushing against the ground), but since the air is less dense than the water expelled by the rocket, little or no forward movement would be produced (we have been through this with the discussion on flyboards further back in this thread).
In a vacuum, the environment is "infinitely" less dense than whatever type of mass a rocket ejects, therefore the forward movement is "infinitely" small. NASA therefore insists on the notion that the mere ejection of mass into the atmosphere or into the void produces enough "recoil energy" to make a rocket attain and sustain staggeringly high speeds.
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Re: Why Rocketry Doesn't Work in the Vacuum

Unread postby rusty on Fri Feb 21, 2014 1:31 pm

Flabbergasted wrote:A water rocket (or ANY rocket for that matter) pushes against a fixed surface (the ground) in order to lift off. If it were possible to launch a water rocket at an altitude of 100 m, ...


There's no doubt this is possible. It's impossible that a water rocket reaches an altitude of several 100 meters (as some of them do) just by pushing against the ground.

Flabbergasted wrote:NASA therefore insists on the notion that the mere ejection of mass into the atmosphere or into the void produces enough "recoil energy" to make a rocket attain and sustain staggeringly high speeds.


And I agree with them, as long as we're talking about ejecting solids or fluids. With gases, it's a different story, at least in the vacuum, because gases can't be "ejected" there.
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Does Rocketry Work in the Vacuum?

Unread postby Flabbergasted on Fri Feb 21, 2014 2:56 pm

Water Rocket Altitude World Record with Onboard Camera (615 m)
http://www.youtube.com/watch?v=ZBV-kphMfSY

The rocket design appears to be similar to this:
Image
http://www.uswaterrockets.com/

The "power" of the rocket is simply compressed air. The water is ejected not as a "liquid" but as a fine spray, making it more efficient when pushing against the ground and air.

Chicken Little also had a go at it:
http://www.youtube.com/watch?feature=pl ... M_Gpw#t=57

A feat which has inspired younger generations:
http://www.youtube.com/watch?feature=pl ... lYlj0#t=98
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