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 I am a Moonie

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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 3:19 am

Auditor #9 wrote:
toxic avenger wrote:
Auditor #9 wrote:
toxic avenger wrote:
youngdan wrote:
Yes, there would be a lot less than 100000 involved.

I've decided to believe that you don't really exist, that you're a conspiracy between other posters on this site to pretend that you exist. It doesn't matter if they tell me that you do, because they would say that, wouldn't they?

Well how many would need to be involved in such a conspiracy (not yours) if there was one ? Just a small handful - you can dig that can't you toxic Wink

You're one of THEM, aren't you?...

There's just you, tonys and youngdan on this site.

I suppose tonys' responses couldn't be made up, so I'll have to trust him and him alone from now on. The irony...
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 3:21 am

Dan, the LM5 lander used Nitrous Oxide fuel for both descent and ascent.

Prior to heading for the moons surface, the LM was attached to the
Command module and the service module. These were in a lunar orbit of
about 60 miles. The gravity here is effectively identical to the
surface gravity.

What was keeping them in orbit was the orbital velocity, providing a
centrigugal force to offset the gravity. A stone tied to a piece of
string and spun over your head.

Tho get to the surface, the LM separated from the CM+SM and burned
engines for 30 seconds to reduce it's orbital velocity, and thereby put
it on a course towards the moon. About an hour later, it burned engines
again to reduce it's speed to touch down speed.

It was all done at quite low speeds really, I don't see any problem with it.

After ascent, the ascent module did not fly straight back to earth. It
joined with the CM+SM, they then dumped the ascent module, which
eventually fell back to the moon, dont know when, and they used all the
fuel in the service module to rocket themselves back to earth.
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 3:26 am

toxic avenger wrote:
Auditor #9 wrote:
toxic avenger wrote:
Auditor #9 wrote:
toxic avenger wrote:
youngdan wrote:
Yes, there would be a lot less than 100000 involved.

I've decided to believe that you don't really exist, that you're a conspiracy between other posters on this site to pretend that you exist. It doesn't matter if they tell me that you do, because they would say that, wouldn't they?

Well how many would need to be involved in such a conspiracy (not yours) if there was one ? Just a small handful - you can dig that can't you toxic Wink

You're one of THEM, aren't you?...

There's just you, tonys and youngdan on this site.

I suppose tonys' responses couldn't be made up, so I'll have to trust him and him alone from now on. The irony...
Do you want to get off this particular horse now girls, before I saddle up myself and come looking for you?
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 3:44 am

When you are faced with being told an inconvenient truth about 100000 people keeping what was the biggest secret ever you have no answer except avoiding it Toxic.

The penalties for revealing a secret are severe here. Not just in the military but in civilian life. If you are put under a gag order you had better shut up. If you are unlucky enough to be served a subpeona called a National Security Letter you can not tell anyone you got it, not your wife, noone

http://en.wikipedia.org/wiki/National_Security_Letter
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 3:54 am

ibis wrote:
youngdan wrote:
I know you are not versed in mechanics Ibis buy your understanding of English is better than you choose right now. The assent would be easy compared to the descent as I have just said. We know that it would be powered on the way up and the only important thing is the force up is greater than the force down for long enough to get the speed up to what is necessary.

No, the point is that you don't need to reach escape velocity at all to go up, any more than a ball thrown from your hand needs to be travelling at escape velocity to go up. You just need to be capable of enough lift to achieve upward motion, and to be able to do it long enough to climb into orbit. There's obviously a trade-off between the speed of ascent and the duration.

Coming down is essentially similar. By the way, you know that the Moon Landers were tested several times in Earth orbit, and once by descending to within 10K of the lunar surface - before they actually landed?

I said that exact same thing and you come along and just repeat what I said.

All you need to go up is a greater force acting up than acting down.

What is achieved by testing a lander in Earth orbit where the force of gravity is zero. On this subject you don't even seem to have common sence
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 3:59 am

Again YD, gravity is not zero in earth orbit, even at 10,000 miles. But if you are orbiting at just the right speed, it will be cancelled out.

Once you slow down, the gravity will start to take affect
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 4:10 am

tonys wrote:
toxic avenger wrote:
Auditor #9 wrote:
toxic avenger wrote:
Auditor #9 wrote:
toxic avenger wrote:
youngdan wrote:
Yes, there would be a lot less than 100000 involved.

I've decided to believe that you don't really exist, that you're a conspiracy between other posters on this site to pretend that you exist. It doesn't matter if they tell me that you do, because they would say that, wouldn't they?

Well how many would need to be involved in such a conspiracy (not yours) if there was one ? Just a small handful - you can dig that can't you toxic Wink

You're one of THEM, aren't you?...

There's just you, tonys and youngdan on this site.

I suppose tonys' responses couldn't be made up, so I'll have to trust him and him alone from now on. The irony...
Do you want to get off this particular horse now girls, before I saddle up myself and come looking for you?
Will you be saddling up a real horse, or one you can win retrospective and conveniently explanatory bets upon?...
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 4:27 am

s Oxide fuel for both descent and ascent.

Prior to heading for the moons surface, the LM was attached to the
Command module and the service module. These were in a lunar orbit of
about 60 miles. The gravity here is effectively identical to the
surface gravity.

What was keeping them in orbit was the orbital velocity, providing a
centrigugal force to offset the gravity. A stone tied to a piece of
string and spun over your head.

Tho get to the surface, the LM separated from the CM+SM and burned
engines for 30 seconds to reduce it's orbital velocity, and thereby put
it on a course towards the moon. quote

Let's take this part. This is easy to understand by all. I will add a few points so that everyone will understand. The gravitational force pulling down depends on, among other things, on the radius r down to the centre of the moon. Because the radius up to the surface is just very very smaller than the radius up to the surface plus 60 miles we can call them the same. This force exactly equal the centrifigal force so that the craft neither falls or rises. This force among other things depends on the speed the craft is travelling in the circle/orbit. If the speed increases it flies up(escapes) and if it slows down it falls.

It is no problem to land on the moon, the problem is to land without splattering into the surface. The Indian probe the other day hit at 2300 mph and it was tiny, not 23000 kg

You EVM as an engineer knows that even at 10mph the momentum of 23000 kg in a sudden impact would buckle all before it. It was not done at low speeds at all and orbital speed at 60 miles if as you say was the height can be checked easily.

The Indians did not even attempt to soft land the probe but will attempt it in 2012. Numerous crashs have occured on Mars where a soft landing in infinately easier.

Nobody even bothers with the ascent because that is easy. You just need enough fuel and a vertical undamaged craft.

.
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 4:34 am

EVM. I know all about gravity at any point. If it wasn't equalled out you would not be in orbit now would you.

Testing a moon landing where the net forces are zero makes no sense so link to it
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 4:52 am

youngdan wrote:
EVM. I know all about gravity at any point. If it wasn't equalled out you would not be in orbit now would you.

Testing a moon landing where the net forces are zero makes no sense so link to it

You have absolutely no idea what you're talking about. I'm sorry to be rude (or bitter and hostile, y'know), but that's the bald and honest truth. You're misunderstanding a very basic principle here - you can escape gravity as slowly as you like. Testing a rocket in Earth orbit makes complete sense if what you want to know is that everythng works. Testing it again, as they did, by dropping towards the lunar surface and pulling up again is the acid test, but it was done. Not, of course, that you are capable of believing that.
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 4:58 am

I must have been lucky to graduate out of UCG then. You are making a fool of yourself as everyone with even basic physics can see.
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 5:08 am

Now you have edited to make yourself look even sillier. You can not escape at low speeds. That is why they call it ESCAPE VELOCITY.

Then you start talking about testing rockets. What everyone else is talking about is testing the lander where the gravitational force is 1/6g.
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 5:09 am

youngdan wrote:
I must have been lucky to graduate out of UCG then. You are making a fool of yourself as everyone with even basic physics can see.

We'll just have to differ on that, I'm afraid. We each think the other a fool, and I'm content to leave it there (as I no doubt should have done earlier), since your opinion of me isn't really troubling me and I doubt mine is troubling you either.
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 5:14 am

youngdan wrote:
Now you have edited to make yourself look even sillier. You can not escape at low speeds. That is why they call it ESCAPE VELOCITY.

You don't have to achieve escape velocity to get into space. This is what I am trying to tell you, with the ball experiment.

You know that a ball thrown from your hand beats gravity, because it goes upward. If you wanted to throw that ball clear out of the atmosphere, you would need to throw it at escape velocity, because that is the only impetus the ball is given. If, on the other hand, you could think of some way to keep a ball going at the much lower speed that allows you to throw a ball up to the ceiling, it would eventually go into space at that speed, even though that speed is much lower than escape velocity.

We have such a way - it is called a rocket. All you need to do is keep the rocket firing long enough to climb into space - it doesn't matter the speed you do it at.

Think of it another way - it takes a certain amount of energy to lift a given mass to a given height above the surface of the planet. The rate is irrelevant.

Look - say we take a firework rocket. They go up (assuming you point them up, and don't jam the stick into the ground). If the rocket continued to fire for long enough, why would it not go all the way up? It can beat gravity at lift off - are you telling me that at some point something other than gravity kicks in, and the force that was sufficient to lift off against gravity at the surface suddenly stops being sufficient to continue lifting the rocket?

Quote :
For a given gravitational potential energy at a given position, the escape velocity is the minimum speed an object without propulsion needs to have sufficient energy to be able to "escape" from the gravity, i.e. so that gravity will never manage to pull it back.
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 6:17 am

We are not talking about reaching space, we are talking about escaping the gravitational forces of the Earth. The space station is in orbit but it has not reached escape velocity and it is still in the grip of the Earth's gravitational pull. It is kept up there as EVM pointed out by the centrifugal force generated by it flying round in a circle. In other words if it all of a sudden stopped circling it would immediately fall back to Earth.

You seem to think that a rocket can burn indefinately. Unfortu
nately this is not the case. The problem faced is that you must get to a velocity where the centrifugal force due to the speed of the object circling is greater than the force of gravity pulling it back. At this point you don't need any rocket force at all as the centrigugal force on it's own flings the object higher and out into space

When this happens the craft leaves Earths gravity and then comes under the suns gravity. From here on it depends on the speed to see whether it is fast enough to move out from the sun or if it is slower then it moves toward the sun and gets burned up.

For a moon shot the calculations are done so that as it swings away from earth orbit it crosses the area of space where it can fall under the influences of the moons gravity. Then the speed is dropped so that the centrifugal force generated by it's circling the moon is equal to the moon's gravity.

Now the part you are missing with the ball or rocket is the bit about it going straight up. In this situation there is no centrifugal force at all acting on the object. The centrfugal force only is generated where there is circular motion. Going straight up can not be done because to lift an object far enough away from the Earth to a point where the Earths gravity would no longer have an effect would take a rocket a thousand miles high. That is why very shortly after launch the rocket levells off and travels to a great extent horizontally while it's altiude begis to rise. This is because it must get the centrigugal force acting as quickly as possible.

The craft goes nowhere in a straight line not even to the space station 220 miles away. It adapts the same eliptical tragectary whether it is to the space station, the moon, Mars or any of the planets.

Some probes have gone by Jupitor and reads later swing by Saturn.

Thinking of a ball going straight up is not what happens. You would have to throw the ball horizontally at great speed for it to rise
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 6:27 am

Ibis. I doubt very much if I ever said you were a fool, even in jest, and definietely do not think so. On this subject your knowledge is lacking as it is not your field and likely not your interest either. But anyway that is how rockets operate
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 6:30 am

I appreciate that whenever you stop powered ascent you need to be at local escape velocity if you want to keep going - the ball example is deliberately simplified, because people appear to be under the misconception that you need to achieve escape velocity during ascent in order to 'beat gravity'. However, the lunar lander ascent stages only needed to get to lunar orbit - and decaying orbit at that, because they only needed to be there long enough to rendezvous. The lunar ascent stages that were used all fell back to the Moon afterwards.

By the way, you know they use a mirror that Neil Armstrong left on the Moon to measure the distance to it using laser pulses?
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 7:02 am

Getting off the moon only needed enough fuel and no malfunctions

Some younger posters want to be right every time and will go to great lenghts to prove themselves right. I don't mind being proved wrong especially on topics on which is not something I have a keen interest in.

However I was once corrected when I assumed that the Bank of England was still a private company like the Federal Reserve by Conor over on P.IE. I did not know that it was nationalised after WW2. I had to admit my mistake.
The American craft goes to the moon next April. If I am wrong then I will be the first to eat humble pie to the great glee of all here.
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 12:00 pm

youngdan wrote:
We are not talking about reaching space, we are talking about escaping the gravitational forces of the Earth. The space station is in orbit but it has not reached escape velocity and it is still in the grip of the Earth's gravitational pull. It is kept up there as EVM pointed out by the centrifugal force generated by it flying round in a circle. In other words if it all of a sudden stopped circling it would immediately fall back to Earth.

You seem to think that a rocket can burn indefinately. Unfortu
nately this is not the case. The problem faced is that you must get to a velocity where the centrifugal force due to the speed of the object circling is greater than the force of gravity pulling it back. At this point you don't need any rocket force at all as the centrigugal force on it's own flings the object higher and out into space

When this happens the craft leaves Earths gravity and then comes under the suns gravity. From here on it depends on the speed to see whether it is fast enough to move out from the sun or if it is slower then it moves toward the sun and gets burned up.

For a moon shot the calculations are done so that as it swings away from earth orbit it crosses the area of space where it can fall under the influences of the moons gravity. Then the speed is dropped so that the centrifugal force generated by it's circling the moon is equal to the moon's gravity.

Now the part you are missing with the ball or rocket is the bit about it going straight up. In this situation there is no centrifugal force at all acting on the object. The centrfugal force only is generated where there is circular motion. Going straight up can not be done because to lift an object far enough away from the Earth to a point where the Earths gravity would no longer have an effect would take a rocket a thousand miles high. That is why very shortly after launch the rocket levells off and travels to a great extent horizontally while it's altiude begis to rise. This is because it must get the centrigugal force acting as quickly as possible.

The craft goes nowhere in a straight line not even to the space station 220 miles away. It adapts the same eliptical tragectary whether it is to the space station, the moon, Mars or any of the planets.

Some probes have gone by Jupitor and reads later swing by Saturn.

Thinking of a ball going straight up is not what happens. You would have to throw the ball horizontally at great speed for it to rise

For some reason I was under the impression too that an object leaving the earth or any gravity well needed to be at escape velocity too but even though it's wikipedia (see wiki escape velocity) I'm sure it's correct when it says that the object needs to be at escape velocity only if it is without propulsion. As ibis says, this IS rocket science for once.

I don't know why I thought that because I posted a thread here on a space elevator not so long ago - this is a long string tied down from the likes of the ISS to earth and involves moving stuff upwards with an elevator. Once up at the platform they can head towards the moon with some rocket propulsion - there is no centrifugal force invloved here.

Now this could also be done with a balloon if a balloon was modified a bit. The balloon would continue to rise up and up using balloon technology but the only thing that would keep it from leaving the earth's atmosphere is the atmosphere itself - or lack of air and atmosphere in space because balloons need atmosphere to operate. However, couldn't a rocket be put onto a balloon and then flown out of the balloon when the balloon reaches its maximum limit ? Check this out
http://www.newscientist.com/blog/technology/2006/09/spaceflight-on-cheap.html

A balloon would not operate in the moon because there is no atmosphere there - they need rockets because rockets act on displacement not air. A jet engine would also get people up there as a jet engine works on air too but it wouldn't work once the atmosphere ran out - it needs air to work. In fact in space when they want to move a little bit all they do is displace a bit of air - blow a jet of air or any common gas out and the spaceship whirls in the oppositie direction. They can calculate these movements perfectly because the amount of gas displaced equals a certain force once outside the atmosphere.

But check it out - it's potentially possible to go the moon on a balloon.

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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 2:29 pm

Dan, I still don't know which bit of going to the moon you do not believe.

I think you guys have agreed the escape velocity debat is irrelevant in this case, as we are dealing with vehicles which can supply their own kinetic energy on demand.

Going to the moon involves going from a Low Earth Orbit to an elliptical orbit whose apogee is at the lunar radius. This is easily done by firing engines in LEO for a specified time. It is a basic transfer orbit mechanism.

On reaching the apogee, you have to accelerate again to stay in the same orbit as the moon, otherwise you'll head back to earth again. The moon itself can be used to help with this bit.

After this burn, you can now drop nicely into a local lunar orbit. And since the moon has no atmosphere, you can orbit as low as you like, just make sure you don't hit a mountain.

Anyway, getting down to the surface from here is a doddle, and not the massive energy release scenario some would iimagine.


Last edited by EvotingMachine0197 on Mon Dec 08, 2008 2:44 pm; edited 1 time in total
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 2:39 pm

http://www.youtube.com/watch?v=pmQ8UPekwTU
Laughing

no atmosphere on the moon eh ? Look at the first minute of that on your break lol
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 4:42 pm

Audi, google the mythbusters flag waving on youtube.

The flag continued to flutter for upto 5 times longer in a vacuum than in air after the same stimulus.
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 5:03 pm

EvotingMachine0197 wrote:
Audi, google the mythbusters flag waving on youtube.

The flag continued to flutter for upto 5 times longer in a vacuum than in air after the same stimulus.

Mythbusters on the flag waving
http://www.youtube.com/watch?v=yhab86KoVjU
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 8:04 pm

That is not correct.

After a very short time the entire contents of the fuel of the rockets is used up and the stages fall back to Earth. The small rockets left can only deliver minute amounts of energy.

To escape, the sourse of power is the centrigugal and without it the craft falls to Earth.

In the future there may be technology delivering huge amounts of energy from a small sourse but presently we rely on rockets.


The centrifugal force as said depends on the velocity and for it to be greater than gravity the velocity must be greater than a certain velocity. This velocity is known as Escape Velocity.

The small rockets do not provide lift as it would be neglible. They provide thrust which increases the velocity horizontally. The resulting higher velocity is what increases the centrifugal force(acting up) acting to overcome gravity(acting down).

On reaching the moon the main forces are the moons gravity and the centrifugal generated by circleling the moon. The energy from the rocket is small compared to these two and the circular notion of the orbit must be established immediately.


I have 2 big problems and 1 small problem.

First, the radiation problem. I am not knowledgeable in this field and rely on the reports of the dangers. I can see with my own eyes the reports that the ISI relatively low to escape it's effects.

Second, is the problem of achieving a soft landing on the moon using just rockets with little energy output and no atmosphere to help you. Landing on Mars is easy compared to the moon. It would not surprise me in the future to see a Mars attempt before a lunar attempt even though it would be a 2 year mission. In this area I have plenty of knowledge.

Thirdly I want to know how they got the lunar rover to the moon surface. They say they strapped it to the side. We will leave aside the problem of stability and the shifting of the centre of gravity this would entail as the readers may not understand the problems entailed.

The question is why there is no video of the astronauts lifting it off the side of the lander. Some feat that was to make Hercules proud.

Maybe they had a JCB up there to lift it down because even at 1/6 weight would you try it.
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PostSubject: Re: I am a Moonie   Mon Dec 08, 2008 8:58 pm

Quote :
The question is why there is no video of the astronauts lifting it off the side of the lander. Some feat that was to make Hercules proud.

Maybe they had a JCB up there to lift it down because even at 1/6 weight would you try it.

"Deployment of the LRV from the LM quad 1 by the astronauts was achieved with a system of pulleys and braked reels using ropes and cloth tapes. The rover was folded and stored in quad 1 with the underside of the chassis facing out. One astronaut would climb the egress ladder on the LM and release the rover, which would then be slowly tilted out by the second astronaut on the ground through the use of reels and tapes. As the rover was let down from the bay most of the deployment was automatic. The rear wheels folded out and locked in place and when they touched the ground the front of the rover could be unfolded, the wheels deployed, and the entire frame let down to the surface by pulleys.

The rover components locked into place upon opening. Cabling, pins and tripods would then be removed and the seats and footrests raised. After switching on all the electronics the vehicle was ready to back away from the LM."

Actually, I would try it. It only massed 210 kg - equivalent to two large adults. Under lunar gravity it only weighed a sixth of that - five and a half stone.
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