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 wrote:
I can see how a rocket is pulled towards a planet/star via gravitational attraction. But I don't see what this has to do with rocket propulsion.
Gravity is just a force applied to the rocket by masses in space/vacuum. Same with a rocket engine attached to the rocket. It can also apply a force on the rocket = propulse the rocket in space/vacuum. Most rocket engines use liquid fuel/oxygene that, when burnt in the engine combustion chamber, ejects gases through a nozzle into space/vacuum that in turn provide the propulsion force.
You can't eject gas into a vacuum. This is at the heart of the space rocket fantasy. As soon as gas from the combustion chamber enters the nozzle and comes in contact with the vacuum it is whisked away into the void. Regard the equation for work done by a gas: Work = Pressure x Volume. When pressure is 0 work is 0. Gas provides no force in a vacuum.
Problem is just not to run out of fuel, as you cannot top up in space/vacuum. Evidently no rocket or space ship cannot carry enough fuel to brake into Moon orbit, land on Moon, start again from Moon and accelerate out of Moon orbit and try to get back to Earth (and brake there) as explained at http://www.heiwaco.tripod.com/moontravel.htm . But apart from that rocketry actually works in vacuum.
Do you have any proof that rocketry works in a vacuum?
Boethius wrote:
You can't eject gas into a vacuum.
Just open the valve of the Magdeburg hemispheres and air enters the vacuum. Vacuum is just lack of air.
So you're saying if a hatch opened and gas left the ship to equalize the pressure, with no extra force applied to the gas, this alone could potentially move the ship.
Well, with what I suppose would be somewhat basic physics, it would be possible to determine just how much air---intended to be blown into the vacuum---would be required to produce the distances and rates of travel proposed to us by NASA.
A chamber of gas relative to the size of say, Dublin, would fit the bill, no? On that note: bollocks.
Boethius wrote:
You can't eject gas into a vacuum.
Just open the valve of the Magdeburg hemispheres and air enters the vacuum. Vacuum is just lack of air.
So you're saying if a hatch opened and gas left the ship to equalize the pressure, with no extra force applied to the gas, this alone could potentially move the ship.
Yes, say that 1 kg of compressed air (no combustion) is leaving the ship into vacuum through a nozzle at 100 m/s velocity, this alone produces a force of 100 N that propulse the ship forward in the vacuum.
So, if this works on Earth and in the vacuum of space...
...we should sell the idea to NASA asap!
Q&A with NASA:
Inflating a Balloon in Space Q: Is it possible to blow up a balloon in space? I would like to know more about the gas laws in space.
A: Yes, it is easy to blow up a balloon in space. The way you inflate a balloon is to put a larger pressure inside the balloon than outside, which is easy to do when the outside pressure is near zero. (...)
Dr. Eric Christian http://helios.gsfc.nasa.gov/qa_sp_ev.html
hoi.polloi wrote:
So you're saying if a hatch opened and gas left the ship to equalize the pressure, with no extra force applied to the gas, this alone could potentially move the ship.
Yes, say that 1 kg of compressed air (no combustion) is leaving the ship into vacuum through a nozzle at 100 m/s velocity, this alone produces a force of 100 N that propulse the ship forward in the vacuum.
Gas can't exist in a boundless, low-pressure, low-gravity vacuum like interstellar space. So it can't be used to move a rocket.
Gas only exists under pressure; in an atmosphere, in a container, in an extremely strong gravitational field, etc... Without pressure individual gas molecules fly away distancing themselves from each other at thousands of meters a second (depending on the specific heat) and no force is exerted in the process (no work done).
Using gas in space is like using ice cubes on the surface of the sun.
Heiwa wrote:
Yes, say that 1 kg of compressed air (no combustion) is leaving the ship into vacuum through a nozzle at 100 m/s velocity, this alone produces a force of 100 N that propulse the ship forward in the vacuum.
So when the *ahem* Lunar Module was depressurized for extra-vehicular activities it trembled and quaked and maybe even went skittling off across the highly reflective surface of the moon.
Boethius wrote:
Gas can't exist in a boundless, low-pressure, low-gravity vacuum like interstellar space.
The gas will evidently continue to exist, when you eject it into zero pressure vacuum. It cannot POUFF POUFF disappear! BTW - what is low-gravity vacuum? I have a feeling you are not serious.
brianv wrote:
Can a ship out of water, by switching on it's propellers, push against themselves to cause forward motion of the ship?
Brian, pardon me - but I think a better question would be: can a hydrojet engine on a ship push the vessel forward if the water jet is sprayed above the water surface?
However, I have already raised this question earlier in this thread - and am still waiting for a serious, no-nonsense answer to it.
Boethius wrote:
Gas can't exist in a boundless, low-pressure, low-gravity vacuum like interstellar space.
The gas will evidently continue to exist, when you eject it into zero pressure vacuum. It cannot POUFF POUFF disappear! BTW - what is low-gravity vacuum? I have a feeling you are not serious.
Heiwa,
gas is only defined as existing within an area where it exerts pressure. Without pressure Boyle's law makes no sense: PV=k is an absurdity if pressure is 0. The Ideal gas law also makes no sense and so on. Gas not under pressure is like a solid without mass. It's nonsensical. You can't have one without the other.
There is no gas in outer space only scattered molecules without relation to one another. NASA and their aligned scientists group these molecules together as "gas" to make it seem like rocket gas can exist in the vacuum. Again, since these molecules do not exert any pressure they do not satisfy the condition of being a gas. But what does NASA care about science? They pick and choose the laws, theories and results to display to the public in order to make their picture of space travel seem plausible. It's starting to seem like there is barely any real science involved in space travel, the majority of the story being fantasy, imagination and trickery.
NB: Low gravity means that there is not much gravity, such as when you are far away from the nearest massive object. A vacuum is exactly what you think it is. Put those two together and you have the conditions of interstellar space through which a rocket must travel.
"NASA Public Affairs Officer Dan Huot recently visited Johnson Space Center's 400,000 cubic foot vacuum chamber, Chamber A, and spoke with Mary Cerimele, the lab manager for this historic facility." (...) "The chamber and its impressive 40-foot diameter door have even been featured in several movies such as "Armageddon" and "Futureworld." As Cerimele jokes, "It's our resident diva."
full link: http://www.youtube.com/watch?v=-ZB3-6uR4nA
Now, please note that Mrs Cerimele is apparently the Lab Manager of this massive vacuum chamber. She's no mere spokesperson/ or public relation lady. So I guess she must know what she's talking about. Yet, let's listen to her:
"It (the James Webb Telescope) is actually gonna go a million miles from Earth, four times farther away than the Moon is from us, and hang out at the L2 Lagrange point, where...at that point...that's why it's so cold, it's very very cold at that point since we're so far from the influence of the Earth and the Moon..."
Wh-a-at? I thought the heat we feel on Earth is due to the Sun? Duh - I must be dramatically misinformed!
Seriously, how can any NASA 'Lab Manager' utter such triple-facepalm-worthy tripe ?
Wh-a-at? I thought the heat we feel on Earth is due to the Sun? Duh - I must be dramatically misinformed! 
