ApolloHoax.net
Apollo Discussions => The Hoax Theory => Topic started by: miker on November 04, 2016, 06:09:56 PM
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I think they had to slow down three different times while going to the moon.
1. To enter into an orbit around the moon.
2. After detaching from the command module, the lunar module had to slow down in order to fall out of orbit.
3. When the lunar module entered the moon's gravitational field and landed softly.
The only way that I can come up with them slowing down in space is to reverse the module to the EXACT opposite of their flight path and fire the main thruster and travel through their exhaust.
I think their fuel was liquid hydrogen and liquid oxygen which burns at 5500°F. The lunar lander had a skin of aluminum foil which melts at about 1200°F.
What I don't know is how fast temperature and heat dissipate in a vacuum, since they had to travel through it at a high velocity and not melt aluminum.
It reminds me of reverse landing a rocket here on the Earth - which hasn't been done yet.
I would appreciate anyone teaching me how they slowed down in a vacuum, in case there is another way, or that the heat is no problem.
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Miker, this is really basic stuff, and perhaps you might want to do a little more work on your own before coming here with what is a request for education on stuff that is:
1. pretty easy to find out
2. at a very basic level of science - ie stuff you should have learned in grade school.
NO, using their own reverse thrust is of course NOT the only way to wash off speed. You *really* need to learn about how orbits and trajectories work.
However, yes, they turned the craft around to use reverse thrust to assist in the slowdowns.
NO, they would not have traveled through any significant part of the 'exhaust'.
NO, the temperature of a particle of exhaust at the moment it burns has virtually NOTHING to do with the infinitesimally tiny amount of residual heat (hint - temperature and heat are two different things) that might be transferred some time later (after the particle had radiated heat out into cold empty space), and *if* any of the particles hit anything 'delicate'. Given they are being sprayed BACKWARDS into a vacuum with a velocity added to that of the spacecraft, why would any of them get overtaken by the spacecraft???
Seriously mate - THINK about this stuff. They are in SPACE, not here on earth, so things are different...
May I suggest you visit Bob Braeunig's excellent site:
http://www.braeunig.us/space/index.htm
and follow the links to the ones about orbital mechanics, Apollo trajectories, etc
Also, do some Wiki-ing before posting more of these requests.. and maybe have a good long look here:
http://jean-fred.com/apollo/poster_high_nasa_apollo.jpg (Warning, this is a BIG image!!)
at a schematic of how Apollo worked. This was done a few years before the actual mission, but it's close enough...
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BTW, we have managed to reverse land rockets for a LONG time, and slowing down in space is much easier than a landing.
As for the landings, research the LLTV / LLRV used as a test bed for the Apollo landings, and the several HUNDRED times it landed on Earth, in MUCH more difficult conditions (6x the gravity, atmosphere, wind)....
Here's me at another forum, giving a history lesson to an Apollo denier..
http://www.unexplained-mysteries.com/forum/topic/227095-merged-did-we-land-on-the-moon/?do=findComment&comment=4346865
Miker, please acknowledge the replies you get, and also acknowledge when you get stuff wrong. That way we will know if you are capable of learning, or have simply decided that you already know 'da troof'.
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It reminds me of reverse landing a rocket here on the Earth - which hasn't been done yet.
SpaceX did it.
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I'm really confused about all this.
I will take time to check out the links you provided.
Thank you very much.
When a person can't admit they're ever wrong, they are rendered unteachable and can't learn any more. I can admit I'm wrong but I do have to do some learning apparently.
Oh, someone just said a reverse rocket landing has been done, I would really like to see that if someone could post a link.
Thank you
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Oh, someone just said a reverse rocket landing has been done, I would really like to see that if someone could post a link.
Their exact words were "SpaceX did it"
You don't feel inclined to google 'SpaceX landing'? Nor type that as a search term in YouTube?
We have to do all the work for you?
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I'm really confused about all this.
I will take time to check out the links you provided.
Good. Please come back and report what you have learned, or be specific about anything you do not understand, or that you dispute - you really need to give your reasoning on *why* you dispute something and preferably check your reasoning by researching it first.
When a person can't admit they're ever wrong, they are rendered unteachable and can't learn any more. I can admit I'm wrong but I do have to do some learning apparently.
Thing is, you have already been given quite a bit of information on the other thread, yet instead of acknowledging that, you posted a new one.... That's not a good sign, but you can rectify it pretty easily - go back to that thread and answer the replies you were given, properly.
Oh, someone just said a reverse rocket landing has been done, I would really like to see that if someone could post a link.
Thank you
Ever hear that proverb about teaching someone to fish...? Not only were you given the exact words you could enter at Google, I also gave to a link to the Apollo LLRV and LLTV - those craft did well over SEVEN HUNDRED 'reverse landings' during the testing and development phases for Apollo... And again, you haven't acknowledged the content of my post properly - do you agree that landing something on the Moon is MUCH easier than here on Earth? If not, why?
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1) You are correct that they slowed down by using reverse thrust.
2) The propellant was not liquid hydrogen/liquid oxygen, it was Aerozine 50/nitrogen tetroxide.
3) The propellant burned at a temperature of about 5500 F in the combustion chamber. By time it left the nozzle it had expanded and cooled dramatically.
4) The exhaust was expelled at a velocity of over 3000 m/s relative to the rocket. So, no, they did not fly through their own exhaust.
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Oh, someone just said a reverse rocket landing has been done, I would really like to see that if someone could post a link.
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Oh, someone just said a reverse rocket landing has been done, I would really like to see that if someone could post a link.
And a few more:
Blue Origin
DC-X
Bell Rocket Belt
SpaceX Grasshopper
And if you extend it to jet engine powered landings, which mechanically speaking are the same as its still a vehicle being held up by pure thrust, there are even more:
Flyboard air
Jetpack JB-10
Williams Aerial System Platform
Harrier jet
F-35
And lots more examples, those are just he ones that I can easily remember the names of
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It reminds me of reverse landing a rocket here on the Earth - which hasn't been done yet.
The main difference is the absence of an atmosphere, which means that the exhaust doesn't encounter anything to slow it down once it leaves the nozzle until late in the landing when it touches the ground. Even then, it spreads into a sheet flowing outwards rather than being reflected back towards the vehicle. Some of the vehicles mentioned in the post above do have to cope with exhaust being reflected from the ground, but these are the multi-nozzle ones like the Harrier where there is inflowing exhaust in the region between the nozzles which goes upwards because it has nowhere else to go.
(http://www.cham.co.uk/phoenics/d_polis/d_applic/d_aero/harrier1.gif)
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Don't forget the LLRV/LLTV...
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SNECMA Atar Volant (https://www.youtube.com/watch?v=C8Fn-W7FLrA), or C.400 P1. Basically a jet engine with a seat.
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miker - go buy the game "Kerbal Space Program", and play around for a few hours. That will teach you a LOT about rockets and spacetravel.
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I'm really confused about all this.
I will take time to check out the links you provided.
Thank you very much.
When a person can't admit they're ever wrong, they are rendered unteachable and can't learn any more. I can admit I'm wrong but I do have to do some learning apparently.
Oh, someone just said a reverse rocket landing has been done, I would really like to see that if someone could post a link.
Thank you
Supercut of multiple Falcon 9 landings (http://www.space.com/33461-spacex-rocket-landings-video-supercut.html), both on land and at sea.
As others have pointed out, the CSM would not have been flying through its own exhaust; there's no air or other medium to impede the exhaust flow. It flies away from the spacecraft at X m/s regardless of the direction the spacecraft is facing.
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The only way that I can come up with them slowing down in space is to reverse the module to the EXACT opposite of their flight path and fire the main thruster and travel through their exhaust.
If the spacecraft is moving at 2000 m/s relative to some frame and performs a retrograde burn (firing against its motion as you say), the exhaust will leave the spacecraft at a speed of maybe 300 m/s say, them the exhaust will have speed of 2300 m/s relative to our frame. In other words, the exhaust is travelling faster than the spacecraft and so the spacecradt does not travel through it.
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Actually, the exhaust runs away at about 3000 m/s relative to the spacecraft.
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Actually, the exhaust runs away at about 3000 m/s relative to the spacecraft.
I may have gotten the figures for specific impulse confused with exhaust velocity.
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Either way, the exhaust moves away from the spacecraft. It would be pretty funny exhaust if it just sat there inside the engine bell.
Putting aside frames and compound vectors aside for the moment, how exactly would one run into the exhaust? For it to make it back to the spacecraft after being blasted out of the engine, it would have to, ITSELF, slow down in space.
(More, it would have to slow to a complete stop relative to the spacecraft then accelerate back towards it. Now unless the J-2 was somehow capable of throwing a gaseous curveball, I simply don't see how this could happen).
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I think, you are overthinking this problem. If you were on a moving spacecraft outside the hull with a ball in your hand and you threw the ball in the direction of travel. It would move away from you, despite the velocity of the spacecraft. The same is true of the exhaust, even if it were possible for the spacecraft to be moving faster than the velocity of exhaust.
In a denser medium such as air or water there would be a problem because of back pressure, but not in a vacuum.
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What's funny is it even works if, for some reason, the exhaust does it's work but then hangs around moving at near-enough-the-same velocity of the spacecraft. Because if there is a velocity change on the spacecraft, then it is one that moves it away from the spent fuel. Once again, there's no way to fly through the stuff.
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Actually, the exhaust runs away at about 3000 m/s relative to the spacecraft.
I may have gotten the figures for specific impulse confused with exhaust velocity.
Specific impulse is exhaust velocity. The only difference is that in the US, "specific impulse" is arbitrarily expressed as the exhaust velocity divided by earth's nominal surface gravity (~9.8 m/sec2). In Europe and elsewhere, the two terms are generally equivalent.
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I'm really confused about all this.
I will take time to check out the links you provided.
Thank you very much.
When a person can't admit they're ever wrong, they are rendered unteachable and can't learn any more. I can admit I'm wrong but I do have to do some learning apparently.
Oh, someone just said a reverse rocket landing has been done, I would really like to see that if someone could post a link.
Thank you
Supercut of multiple Falcon 9 landings (http://www.space.com/33461-spacex-rocket-landings-video-supercut.html), both on land and at sea.
As others have pointed out, the CSM would not have been flying through its own exhaust; there's no air or other medium to impede the exhaust flow. It flies away from the spacecraft at X m/s regardless of the direction the spacecraft is facing.
Thanks for the link jfb. I hadn't previously seen the footage of the stage (around 0:43 in the video) descending from space. It's amazing to think that it's still less than a year since SpaceX managed their first successful first stage landing, and that they managed five such successful landings in seven months.
And, by the way, welcome to Apollohoax!
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Actually, the exhaust runs away at about 3000 m/s relative to the spacecraft.
I may have gotten the figures for specific impulse confused with exhaust velocity.
Specific impulse is exhaust velocity. The only difference is that in the US, "specific impulse" is arbitrarily expressed as the exhaust velocity divided by earth's nominal surface gravity (~9.8 m/sec2). In Europe and elsewhere, the two terms are generally equivalent.
I know. Hence why the value of the figures are different.
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Don't forget the LLRV/LLTV...
Don't forget the original flying bedstead - 25 years before Apollo 11
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Don't forget the original flying bedstead - 25 years before Apollo 11
I had never seen this one before. Kind of makes those who believe that vertical landings were next to impossible look even more foolish(JW)
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Don't forget the original flying bedstead - 25 years before Apollo 11
I had never seen this one before. Kind of makes those who believe that vertical landings were next to impossible look even more foolish(JW)
You can see the original at the Science Museum in London
https://en.wikipedia.org/wiki/Rolls-Royce_Thrust_Measuring_Rig
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Don't forget the LLRV/LLTV...
Don't forget the original flying bedstead - 25 years before Apollo 11
Or the Bell X-14
https://en.wikipedia.org/wiki/Bell_X-14
Or the Bell Model 65 (1954!)
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And the French SNECMA Atar Volant, as well as many others.
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Thinking that the LM would pass through its own exhaust is the same thing as thinking you can shoot yourself simply by firing a bullet in the same direction as you are traveling.
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Thinking that the LM would pass through its own exhaust is the same thing as thinking you can shoot yourself simply by firing a bullet in the same direction as you are traveling.
Yep. It is no different than being in the back of a plane and firing a gun forward. Will the bullet simply hover? That is one of those rare occasions where "common sense" is correct. Of course it will not.
Somehow, the claimants are unable to figure this out.
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Thinking that the LM would pass through its own exhaust is the same thing as thinking you can shoot yourself simply by firing a bullet in the same direction as you are traveling.
Well, you could if you were facing a very strong wind. Like if you were sitting on the nose of the space shuttle during early launch.
I remember grimacing when I heard, during a live Columbia post-accident press conference, one of the mission managers claim that a piece of mere foam was much too light to possibly damage the orbiter during launch. Even engineers who should know better can suffer failures of intuition.
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Thinking that the LM would pass through its own exhaust is the same thing as thinking you can shoot yourself simply by firing a bullet in the same direction as you are traveling.
Well, you could if you were facing a very strong wind. Like if you were sitting on the nose of the space shuttle during early launch.
I remember grimacing when I heard, during a live Columbia post-accident press conference, one of the mission managers claim that a piece of mere foam was much too light to possibly damage the orbiter during launch. Even engineers who should know better can suffer failures of intuition.
One of the amusements of seat-of-pants mission design in Kerbal Space Program is trying too hard to get over the altitude/attitude hump. Stick too many SRB's on your first stage and you have the excitement of finding yourself reaching orbital velocity whilst still in atmosphere. It rarely ends well.
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Thinking that the LM would pass through its own exhaust is the same thing as thinking you can shoot yourself simply by firing a bullet in the same direction as you are traveling.
Well, you could if you were facing a very strong wind. Like if you were sitting on the nose of the space shuttle during early launch.
I remember grimacing when I heard, during a live Columbia post-accident press conference, one of the mission managers claim that a piece of mere foam was much too light to possibly damage the orbiter during launch. Even engineers who should know better can suffer failures of intuition.
Yeah. I've seen Columbia's reconstructed left wing, and undergone the case study training. It's often referred to as a "failure of imagination", although a host of organizational factors were part of it.
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Thinking that the LM would pass through its own exhaust is the same thing as thinking you can shoot yourself simply by firing a bullet in the same direction as you are traveling.
Yep. It is no different than being in the back of a plane and firing a gun forward. Will the bullet simply hover? That is one of those rare occasions where "common sense" is correct. Of course it will not.
Somehow, the claimants are unable to figure this out.
Their confusion becomes understandable (to me at least) when you take an atmosphere into consideration and lower speeds to every-day level: suppose you stick your head out of the window of a driving car and spit in the forward direction...
And then there's the result of peeing against the wind, which as a child you are told to avoid. To not run into your exhaust ::)