What If I Told You Rockets Just Don't Work In Space? | |
Anonymous Coward User ID: 61365278 Spain 08/09/2014 10:40 AM Report Abusive Post Report Copyright Violation | Actually rockets maintain the speed that they left orbit in when they reach space although thrusters do not work in space... their needs to be a certain amount of gravity for thrusters to work. Quoting: Anonymous Coward 35149860 Incorrect, thrusters work in zero gravity hard vacuum. Whenever you throw something in one direction you (the thrower) ALWAYS receives an impulse in the opposite direction. You are correct that kinetic energy does not retard perceivably in open space, due to no air friction. |
I*D*W User ID: 61391387 United States 08/09/2014 10:44 AM Report Abusive Post Report Copyright Violation | Close. Quoting: Anonymous Coward 60583524 Rockets work by forcefully expelling gas, which is created by burning liqud or solid fuels. So yes, nasa sorta brought their own. The expelled gases push the rocket forward because of the 'equal and opposite reaction'. This force (expelled gas) acts upon the mass (the rocket) regardless, a reference mass (air, water, solids) is not required for this law to apply. Do you really think that baloon below will moves into space? [link to www.youtube.com (secure)] ---------- Opie, you're dumber than a gaggle of NASA fanboys and you make the truth movement look retarded. please shut up. Here's a simple proof you're full of shit. Why does it take 2 firemen to hold a three and a half inch hose when it's turned on? you think it's pushing against the air? The recoil of a gun begins to occur the instant the bullet starts moving in the barrel, it's ebcause of Newtons third law. The energy of the bullet is equal to the energy of the recoil. Rockets work because the gasses are expelled at extreme velocity, the energy imparted is equal to 1/2 the mass of the gasses time the velocity of the gasses exiting the rocket nozzle squared Ke=1/2 Mass (velocity X velocity) If you have a rocket with a thousand pounds of fuel and oxidizer and burn it, the expansion of the gasses in the combustion chamber reaches extreme pressure, which expels the gasses from the rocket engine's nozzle at very high velocities. let us use a hypothetical velocity of 10,000 ft per second in the formula E = 1/2 1000lbs (10,000ft/sec X 10,000ft/sec) E=500 X 100,000,000 = 50,000,000,000 ft/pds. Thats 50 billion ft pounds of energy, and this is why rockets can accelerate to extremely high velocities. |
IWASTHERE (OP) User ID: 61387630 Italy 08/09/2014 10:47 AM Report Abusive Post Report Copyright Violation | Close. Quoting: Anonymous Coward 60583524 Rockets work by forcefully expelling gas, which is created by burning liqud or solid fuels. So yes, nasa sorta brought their own. The expelled gases push the rocket forward because of the 'equal and opposite reaction'. This force (expelled gas) acts upon the mass (the rocket) regardless, a reference mass (air, water, solids) is not required for this law to apply. Do you really think that baloon below will moves into space? [link to www.youtube.com (secure)] ---------- Opie, you're dumber than a gaggle of NASA fanboys and you make the truth movement look retarded. please shut up. Here's a simple proof you're full of shit. Why does it take 2 firemen to hold a three and a half inch hoses when it's turned on? you think it's pushing against the air? Hey genius, "nice" example. Do the hoses weight into space as well? ------------- Last Edited by IWASTHERE on 08/09/2014 10:48 AM |
Anonymous Coward User ID: 31496863 Canada 08/09/2014 10:47 AM Report Abusive Post Report Copyright Violation | |
Anonymous Coward User ID: 16341184 United Kingdom 08/09/2014 10:59 AM Report Abusive Post Report Copyright Violation | |
Anonymous Coward User ID: 58213262 United States 08/09/2014 11:07 AM Report Abusive Post Report Copyright Violation | |
Anonymous Coward User ID: 61365278 Spain 08/09/2014 11:10 AM Report Abusive Post Report Copyright Violation | |
IWASTHERE (OP) User ID: 61387630 Italy 08/09/2014 11:12 AM Report Abusive Post Report Copyright Violation | |
IWASTHERE (OP) User ID: 61387630 Italy 08/09/2014 11:17 AM Report Abusive Post Report Copyright Violation | |
IWASTHERE (OP) User ID: 61387630 Italy 08/09/2014 11:34 AM Report Abusive Post Report Copyright Violation | Another Q that comes in mind just right now is: WHY they did choose a 0 altitude location at the sea level as a launching point? For example, at 13.000 feet, they would make it so much less expensive about fuel AND stuff. Last Edited by IWASTHERE on 08/09/2014 11:45 AM |
Anonymous Coward User ID: 16341184 United Kingdom 08/09/2014 11:35 AM Report Abusive Post Report Copyright Violation | @OP Quoting: Anonymous Coward 61365278 A vacuum environment does not stop action/reaction from happening. Only a tiny fraction of a rockets thrust is a result of pushing against the air, in fact that extra push is less than the friction incident upon the nose due to the air. So a rocket is actually more efficient in space. The bulk of the rockets thrust is just a result of throwing mass out the back at high speed. The total integrated kinetic energy of the complete system (rocket and exhaust) remains zero, the rocket exhaust speeding one way, the rocket body the other. An ion thruster uses this effect also, only it throws a tiny mass out at very high speed. To understand it conceptually imagine you are in free space clinging onto an asteroid the size of a car. Now you stand up and jump as hard as you can, you would depart the asteroid and move in one direction, but the asteroid would start moving a little in the opposite direction. Now imagine you are in space clucthing a fist sized rock, you throw it as hard as you can, the rock flies forward but you fly backward a little. If the rock is the same mass as you then you both fly in opposite directions at equal velocities. WORD! I'm going to say false, unless you meant to say the derivative of the kinetic energy with respect to velocity is conserved. The kinetic energy is increasing all the time, it's a scalar value and even if it wasn't the difference between the total sum of exhaust KE and the Rocket KE is increasing too. Just sayin |
IWASTHERE (OP) User ID: 61387630 Italy 08/09/2014 11:58 AM Report Abusive Post Report Copyright Violation | From wikipedia [link to en.wikipedia.org] The Saturn V reached 400 feet per second (120 m/s) at over 1 mile (1,600 m) in altitude. Does anyone know how much liters per second the Saturn V rocket did blow away? -------- |
Anonymous Coward User ID: 54171175 Spain 08/09/2014 12:04 PM Report Abusive Post Report Copyright Violation | @OP Quoting: Anonymous Coward 61365278 A vacuum environment does not stop action/reaction from happening. Only a tiny fraction of a rockets thrust is a result of pushing against the air, in fact that extra push is less than the friction incident upon the nose due to the air. So a rocket is actually more efficient in space. The bulk of the rockets thrust is just a result of throwing mass out the back at high speed. The total integrated kinetic energy of the complete system (rocket and exhaust) remains zero, the rocket exhaust speeding one way, the rocket body the other. An ion thruster uses this effect also, only it throws a tiny mass out at very high speed. To understand it conceptually imagine you are in free space clinging onto an asteroid the size of a car. Now you stand up and jump as hard as you can, you would depart the asteroid and move in one direction, but the asteroid would start moving a little in the opposite direction. Now imagine you are in space clucthing a fist sized rock, you throw it as hard as you can, the rock flies forward but you fly backward a little. If the rock is the same mass as you then you both fly in opposite directions at equal velocities. WORD! I'm going to say false, unless you meant to say the derivative of the kinetic energy with respect to velocity is conserved. The kinetic energy is increasing all the time, it's a scalar value and even if it wasn't the difference between the total sum of exhaust KE and the Rocket KE is increasing too. Just sayin yes, my bad, KE is scalar, no direction vector. I guess I was meaning to say something like: in free space, the centre of gravity of the rocket and exhaust remains fixed. I think this might even hold true regardless of how crazy the rockets path was. |
Anonymous Coward User ID: 22197206 United States 08/09/2014 12:06 PM Report Abusive Post Report Copyright Violation | From wikipedia [link to en.wikipedia.org] Quoting: IWASTHERE The Saturn V reached 400 feet per second (120 m/s) at over 1 mile (1,600 m) in altitude. Does anyone know how much liters per second the Saturn V rocket did blow away? -------- Depends on the model. The F1 The fuel pump produced 15,471 US gallons (58,560 litres) of RP-1 per minute while the oxidizer pump delivered 24,811 US gal (93,920 l) of liquid oxygen per minute. [link to en.wikipedia.org] |
Anonymous Coward User ID: 54171175 Spain 08/09/2014 12:07 PM Report Abusive Post Report Copyright Violation | I should have said: "The total integrated momentum of the complete system (rocket and exhaust) remains zero, the rocket exhaust speeding one way, the rocket body the other." Thanks for the correction, refreshing to brush against someone with brains. |
Anonymous Coward User ID: 61382997 United Kingdom 08/09/2014 12:13 PM Report Abusive Post Report Copyright Violation | |
IWASTHERE (OP) User ID: 61387630 Italy 08/09/2014 12:17 PM Report Abusive Post Report Copyright Violation | |
Anonymous Coward User ID: 16341184 United Kingdom 08/09/2014 12:20 PM Report Abusive Post Report Copyright Violation | I should have said: Quoting: Anonymous Coward 54171175 "The total integrated momentum of the complete system (rocket and exhaust) remains zero, the rocket exhaust speeding one way, the rocket body the other." Thanks for the correction, refreshing to brush against someone with brains. As Sir Isaac said. "If a body impinges upon another, and by its force changes the momentum of the other, that body also (because of the equality of the mutual pressure) will undergo an equal change, in its own momentum, toward the contrary part" So you could save a lot of typing by just saying in a rocket , momentum is conserved, that's the easiest way to think about rockets. :) |
Anonymous Coward User ID: 61395732 United Kingdom 08/09/2014 12:26 PM Report Abusive Post Report Copyright Violation | |
Rxel User ID: 9473222 Lithuania 08/09/2014 01:28 PM Report Abusive Post Report Copyright Violation | In Talmud it is said: sky consists of Fire and Water (atomic energy, ether). Did you know, that ppl in closed capsule after 14 hours lose feeling of time. Did you noticed, that most astronauts are stupid rednecks. That most shuttles lift empty. That NASA shows you on TV computer game. |
Anonymous Coward User ID: 54171175 Spain 08/09/2014 01:30 PM Report Abusive Post Report Copyright Violation | A. better question is how would you vent heat in space during prolonged flight. Quoting: Anonymous Coward 61382997 Heat pumps and radiators, the heat pump establishes a large thermal potential between the radiators. The hot radiator allowed to "radiate" infra red EM into space. Much management can be done for free, fat heat pipes allowing radiators to transfer heat from hot side to cold side of craft. I suppose you think heat cannot be transferred through a vacuum, did you ever stop to think that the sun feels warm to us, that warmth travelling across the vacuum? Or maybe you think the sun is within our atmosphere, the whole "sun being 93 million miles away" thing being a giant conspiracy lol. TIP: The internet can be used for reading as well as writing. |
DDD123 User ID: 41210324 United States 08/09/2014 01:32 PM Report Abusive Post Report Copyright Violation | |
Anonymous Coward User ID: 54171175 Spain 08/09/2014 01:34 PM Report Abusive Post Report Copyright Violation | I think it would have to be: in a rocket , momentum is conserved when also considering exhaust gasses. Otherwise the reader might not consider the exhaust and think it a false statement. Because when considering only the rocket it's momentum increases relative to it's launch point. |
DDD123 User ID: 41210324 United States 08/09/2014 01:36 PM Report Abusive Post Report Copyright Violation | A. better question is how would you vent heat in space during prolonged flight. Quoting: Anonymous Coward 61382997 That's actually a major issue in space electronics, since there is no air for convective heat transfer. You have to rely on conduction to get heat to radiators, then radiation for the heat to leave the system. I actually worked on a cubesat project with 3 FPGA's all needing sinking. The obvious answer was using 3 heat pipes out to a radiator, which is what we ended up doing. From many, covfefe |
DDD123 User ID: 41210324 United States 08/09/2014 01:40 PM Report Abusive Post Report Copyright Violation | A. better question is how would you vent heat in space during prolonged flight. Quoting: Anonymous Coward 61382997 That's actually a major issue in space electronics, since there is no air for convective heat transfer. You have to rely on conduction to get heat to radiators, then radiation for the heat to leave the system. I actually worked on a cubesat project with 3 FPGA's all needing sinking. The obvious answer was using 3 heat pipes out to a radiator, which is what we ended up doing. Technically, the mechanism of heat transfer inside of a heat pipe is convection, but that's just splitting hairs. From many, covfefe |
IWASTHERE (OP) User ID: 61400789 Italy 08/09/2014 04:56 PM Report Abusive Post Report Copyright Violation | |
Shadow Dwelling Fixer User ID: 25332527 United States 08/09/2014 04:58 PM Report Abusive Post Report Copyright Violation | If you told us that, you would be an idiot. Free speech is never free. Well I know it wasn't you who held me down Heaven knows it wasn't you who set me free So often times it happens that we live our lives in chains And we never even know we have the key - Eagles |
Anonymous Coward User ID: 15309643 United Kingdom 07/07/2016 05:40 PM Report Abusive Post Report Copyright Violation | There is no reason why they can. Its the current physycs, see third Newtow's law. Quoting: IWASTHERE :truestory: NOW the question is: 1 - Did they use something else about the engine type? 2 - Does the out space really is a vacuum environment? 3 - Are there any other question about that? --------- A gas undergoing Joule free expansion does no work. Someone should tell NASA. |
Anonymous Coward User ID: 72316114 United States 07/25/2016 01:45 AM Report Abusive Post Report Copyright Violation | There is no reason why they can. Its the current physycs, see third Newtow's law. Quoting: IWASTHERE :truestory: NOW the question is: 1 - Did they use something else about the engine type? 2 - Does the out space really is a vacuum environment? 3 - Are there any other question about that? --------- I think if you have a vehicle it has to push against something. Cars push against the road, aeroplanes push against the air. There is nothing to push against in space so NASA would have to bring there own stuff with them to push against, I think. And you would be correct. It's called a nozzle. [link to en.wikipedia.org] Indeed, a parabolic nozzle ensure the exhausts last contact with the rocket is dead in line with the rockets body. Without the nozzle lots of radial force is generated which is cancelled and wasted. Yes, look at the engine bells of the Saturn V 1st and 2nd stage engines...they are significantly different in their shape, as the 2nd stage engines operate in a different atmospheric pressure than the 1st stage engines. Each stage is optimized for it's general operating environment. Rocket science...with gobs of math, physics and who knows what all behind it... |
Anonymous Coward User ID: 72631277 United States 07/25/2016 01:53 AM Report Abusive Post Report Copyright Violation | There is no reason why they can. Its the current physycs, see third Newtow's law. Quoting: IWASTHERE :truestory: NOW the question is: 1 - Did they use something else about the engine type? 2 - Does the out space really is a vacuum environment? 3 - Are there any other question about that? --------- Do you even Robert H. Goddard, bro? |