Faking the moon landings

[JayUtah]

My question to you is how big were the chambers to test the LM engine in...

Engine tests and system tests don't use the same chambers.  The LM was tested for pressure integrity, thermal design, etc. in a regular vacuum chamber that's essentially just large enough to accommodate the vehicle.  These go down to pretty much an undetectable pressure.  Those tests didn't include propulsion system tests.  Rocket motor tests happen in an entirely different kind of chamber that's specially made to maintain the vacuum even while the engine is firing.  Obviously if the engine supplies many kilograms of exhaust products, the vacuum wouldn't last long.  These are more accurately called "altitude chambers," and have special designs and equipment to maintain a mostly-vacuum condition while the engine is firing.  They don't simulate total vacuum or space-level vacuum, but rather the pressure at an equivalent altitude of hundreds of thousands of feet.  For engineering test purposes, this is functionally indistinguishable from vacuum.  The price you pay for the ability to so quickly dispose of exhaust products and thus maintain a vacuum is that the vacuum is only in the neighborhood of 0.1 psi.

...and secondly how big would the chamber have needed to be to actually simulate the entire landing scene. I assume huge.

Yes.  See for yourself in the various videos, especially the LRV "Grand Prix."

[benparry]

My question to you is how big were the chambers to test the LM engine in...

Engine tests and system tests don't use the same chambers.  The LM was tested for pressure integrity, thermal design, etc. in a regular vacuum chamber that's essentially just large enough to accommodate the vehicle.  These go down to pretty much an undetectable pressure.  Those tests didn't include propulsion system tests.  Rocket motor tests happen in an entirely different kind of chamber that's specially made to maintain the vacuum even while the engine is firing.  Obviously if the engine supplies many kilograms of exhaust products, the vacuum wouldn't last long.  These are more accurately called "altitude chambers," and have special designs and equipment to maintain a mostly-vacuum condition while the engine is firing.  They don't simulate total vacuum or space-level vacuum, but rather the pressure at an equivalent altitude of hundreds of thousands of feet.  For engineering test purposes, this is functionally indistinguishable from vacuum.  The price you pay for the ability to so quickly dispose of exhaust products and thus maintain a vacuum is that the vacuum is only in the neighborhood of 0.1 psi.

...and secondly how big would the chamber have needed to be to actually simulate the entire landing scene. I assume huge.

Yes.  See for yourself in the various videos, especially the LRV "Grand Prix."

ah ok cool. thanks a lot Jay

[Peter B]

[ker-snippity]

Grumman were apparently contracted by NASA to design and build the LM, and after they were satisfied it would work, they handed it over to NASA, who allegedly put it through its paces in space, where it apparently performed exactly as stated on the tin.

[snip again]

You know all this of course, but why would any of those contractors have known that all their hard work was just part of NASA’s plan to fool the world? The rockets first stage was the only part that had to work to a certain degree, as is plainly seen in the original live news broadcasts from the time of the events.

By what reasoning do you assume that everyone working for, or contracted to NASA would have to be in on the fraud, including the cleaners? Did any of those contractors test the hardware in the environment it was made for? Those contractors would not necessarily have to be in on the fraud, and would not necessarily have built something that worked. They merely built something that they thought would work, because like you, they had complete trust in the science presented to them by NASA.

So perhaps you'd like to explain why the appearance of the LM changed over the months from the time that Grumman won the contract to the point that the design was fixed. There are at least two well known images of early designs for the LM which are noticeably different from what was actually presented to the public.

Why the changes? If it didn't have to actually work in space what did it matter what it looked like? Did NASA have quarterly competitions for its design staff to come up with better looking LM pictures which they'd send over to Grumman?

Or did Grumman keep tinkering with the design because...[drumroll]...they changed it until they had a design which actually worked in space and on the Moon?

[JayUtah]

I should probably clarify that "while the engine is firing" is a duration measured small numbers of seconds, if not in fractions of a second.  The test objective is usually just to see whether the engine will start in a vacuum and achieve steady-state combustion.  You don't need to test it for dozens of a second in ground-based testing.  For full-duration firing tests, you test in space (e.g., LM-1 and almost LM-2) once you've validated engine-start capability in a vacuum chamber.  For the LM, a special-case test was run with a full-scale LM mockup initially in full vacuum, to see what the effect of APS exhaust impingement would be in a vacuum with the LM descent stage directly beneath it.  A combination of full-vacuum and high-flow altitude chambers was used, the two being connected together with pressure-operated valve.

One of the problems you run into in engineering with fluids is the need to move fluid at high flow rates, to high volumes, at high pressure differences.  Most notably this happens in hydraulics and pneumatics where pumps can supply fluid either at high volume or high pressure, but not both at the same time.  When you need both, you use an accumulator.  The pumps supply fluid at high pressure and low flow rates, and it builds up to a high volume and high pressure in the accumulator over time.  Then the accumulator has enough volume stored at high enough pressure to supply the load -- such as for a large-scale actuator.  This introduces a duty cycle into the design, to allow the pumps to restore volume and pressure as needed.

The vacuum scenario is the accumulator problem in reverse.  Vacuum is the commodity you want.  You can get a small volume of hard vacuum easily.  If you need a large volume of hard vacuum, it takes time -- but it can be done.  You run your test in a small chamber of hard vacuum until pressure builds to a certain (unacceptable) amount, and then you vent that chamber into larger chamber in which you've built up a larger volume of vacuum over a long time prior to the test, your "vacuum accumulator."  With this technique you can get harder vacuums for longer time, in test regimes that produce gas as part of the test.

[Echnaton]

Grumman were apparently contracted by NASA to design and build the LM, and after they were satisfied it would work, they handed it over to NASA, who allegedly put it through its paces in space, where it apparently performed exactly as stated on the tin.

Let's put aside from all the wishy washy "apparently" qualifications in this statement. Gruman and all the hardware builders were monitoring performance tests and actual flight performance. They knew when things didn't work as planned because their engineers were at the facilities where the tests were being conducted. You don't see them in films often but there were rooms full of hardware contractor's employees involved in every mission.  This notion of compartmentalization between NASA and contractors is laughable ignorant.

[Glom]

I still cannot believe this guy is getting responses. He is clearly a troll...

Clearly, and not a very imaginative or intelligent one either.

He will waste your time...

Yes and no.  I haven't responded to every single post he's made, mostly because I choose not to spend the time on self-debunking nonsense.  However in some cases it's worth responding to, not because he's going to acknowledge the answer and incorporate it into his argument, but because truth and knowledge is best served by having a response on the record in the same place where he made his accusations.  Consider that someone Googles his way to apollohoax.net, sees a post alleging that NASA simply spoonfed nonsense to unwitting contractors, and then -- absent a cogent response -- goes away thinking that's a suitably well informed analysis.  Instead what that hypothetical lurker sees is an accusation laid bare as ignorant nonsense by those who work in the field.  The rebuttal to the claim appears in the same space as the claim itself, even if the original claimant hasn't the brains or the inclination to respond to it.  Setting the record straight may be time-consuming, but it's not always a waste of time.

Yes. The argument about just ignoring the cranks is wrong. We have seen what that has led to. Wrongness must be challenged.

[benparry]

I still cannot believe this guy is getting responses. He is clearly a troll...

Clearly, and not a very imaginative or intelligent one either.

He will waste your time...

Yes and no.  I haven't responded to every single post he's made, mostly because I choose not to spend the time on self-debunking nonsense.  However in some cases it's worth responding to, not because he's going to acknowledge the answer and incorporate it into his argument, but because truth and knowledge is best served by having a response on the record in the same place where he made his accusations.  Consider that someone Googles his way to apollohoax.net, sees a post alleging that NASA simply spoonfed nonsense to unwitting contractors, and then -- absent a cogent response -- goes away thinking that's a suitably well informed analysis.  Instead what that hypothetical lurker sees is an accusation laid bare as ignorant nonsense by those who work in the field.  The rebuttal to the claim appears in the same space as the claim itself, even if the original claimant hasn't the brains or the inclination to respond to it.  Setting the record straight may be time-consuming, but it's not always a waste of time.

Yes. The argument about just ignoring the cranks is wrong. We have seen what that has led to. Wrongness must be challenged.

I do know what you mean Glom but you could spend the rest of your lives with these idiots

[gillianren]

I do know what you mean Glom but you could spend the rest of your lives with these idiots

Sure.  But it's a valuable thing to do in and of itself.  We'll never convince this guy, but at the same time, we're teaching things like "look things up for yourself" and "don't fall for the more interesting story" to anyone reading.  We have to fight anti-scientific nonsense, because it literally saves lives.

[JayUtah]

Even in the merest practical sense, someone has to clean up the garbage on the beach even though we know tomorrow there will be a whole new batch of garbage.  There is certainly a moral imperative to instill the values of critical thinking and research.  But sometimes people volunteer to clean up the garbage just because they don't like looking at it.  It's a thankless task, and one that has no influence over those who are leaving the trash.  I correct misconceptions because that's one way I can convert spare time into personal satisfaction.

[Echnaton]

I do know what you mean Glom but you could spend the rest of your lives with these idiots

No one can ever stop them from talking. It is having a place where anyone can come make a claim, face critics and have the opportunity to respond that is valuable, even if we all know it is nonsense and failure of the claim is sure to be the end result.

They all eventually get bored or do something that makes them worthy of being banned from this forum. So it isn't entirely open ended.

[AtomicDog]

Now cambo is just repeating himself.

[cambo]

I did NOT learn to generate a theory and then only find evidence to prove me right

Don’t talk crap, if I find evidence which proves me right, then the evidence to the contrary must be wrong, right? Or am I overcomplicating things? I know what you were trying to say, but that’s not the way you wrote it down.

A car has a trunk, whereas a spaceship would have a hold, which should have given you a clue that I was using subtle humour.

You made a statement. I read it. I love humor (or humour for my friends in the UK). Love it. Your statement was not humor (not even subtle) - you made the statement, own it, admit you misspoke and let's move on.

It was a joke and you didn’t get it, because like everyone else on here, you are so busy looking for flaws in HB’s comments, you fail to spot sarcasm and humour, even when it should be obvious, so instead of resorting to these childish attacks on my credibility, why don’t you either concede that you may have misconstrued my comment, or just let it go and move on as you put it?

It’s a well-known fact that the majority of Americans just don’t get British humour, as it’s too subtle and clever for them to grasp. There’s an old saying that goes something like “you can take an American to see Ricky Gervais, but you can’t make it laugh”, or words to that effect.

You don't need to see blueprints of an umbrella to prove it can unfold - just open it

So when did you last unfold a LRV?

When did you? You missed the point of the statement, entirely.

No I didn’t, it was a terrible analogy. Nearly everyone over the age of six knows how to open an umbrella, so it is you that missed my point entirely.

You fail to see the difference between controlling an aircraft and controlling a spacecraft, which are two entirely different concepts.

The principal of CG, pitch, yaw, roll, energy, thrust, etc. still apply. Even someone like myself can understand that. Why can't you? Why do you insist on ad hominem attacks when proven incapable of following a simple, proven principle of science?

An aircraft relies on air to manoeuvre, which we are told there is a severe lack of in space. So go on Mr clever clogs, describe the principle which governs an aeroplanes ability to manoeuvre in flight, and then explain how that principle is applied to a crafts manoeuvrability in a vacuum.

Did you misread my post? Or have you been reading other people’s replies and got yourself a little confused? In any case, that was a rash statement on your part, and it shows that it is you with a lack of understanding and I would suggest that you put a little more thought into your posts in future to avoid any further embarrassment. You made the statement, own it!

The rover debate came to a conclusion some time back

Yes it did. Back when Apollo deployed and used it on the Moon; in front of a WORLDWIDE audience. You are the only one that insists that blueprints are the ONLY way to prove it existed/worked as designed.

I think you’ll find that I’m only one among millions of people who would find it absurd that the plans to build a working Rover, LM and Saturn V rocket are nowhere to be found, along with the tools used to build them. Oh but wait, you and millions of others have seen live TV footage which is proof of their authenticity. Pardon me for being such a naive fool.

You fail to understand a simple concept, one person, just one, that knows will inevitably tell another

Not if they’ve signed a contract. Can you even begin to imagine what it would be like to be sworn to secrecy by your government, because I certainly can? The responsibility must be enormous, and what about the people who refuse to sign it? I would imagine they would be in the same situation, only a lot poorer. To blab would be an act of treason in the eyes of their government, and they, and I suspect their families would pay the price.

You also forgot to quote your source on the paragraph with the math

By your own admission you are not one of the more “educated” members on here, and it shows, which is a good thing as you still have a chance to free yourself from the shackles of your indoctrination, but if you’re incapable of looking up gravity equations, then you aren’t deserving of my attention.

[Peter B]

Eight months for a reply? If I took that long at work I'd get in trouble.

Okay, well, I suppose that means I should come back in October to get a reply to my questions...

[ka9q]

An aircraft relies on air to manoeuvre, which we are told there is a severe lack of in space. So go on Mr clever clogs, describe the principle which governs an aeroplanes ability to manoeuvre in flight, and then explain how that principle is applied to a crafts manoeuvrability in a vacuum.

The basic laws of physics are the same in space as on earth. They include conservation of mass/energy, conservation of angular momentum, conservation of linear momentum, and the second law of thermodynamics (mass/energy conservation is actually the first law).

So to turn either an aircraft or a spacecraft you need torque. How you generate that torque differs, but the result is the same - the vehicle turns around the torque axis at a rate proportional to the torque times time divided by the moment of inertia. Angular momentum is conserved in both cases; in the spacecraft case, the sum of the spacecraft angular momentum plus its reaction control propellant is the same before and after the thruster firing. In the case of the aircraft, the sum total angular momentum of the aircraft and the air surrounding it also remains constant.

Spacecraft and aircraft can be navigated by the same or similar means. Both can use inertial guidance systems, which also rely on the principles of momentum conservation. Spacecraft in low earth orbit can today be navigated by the GPS. And so on.

Anyone who actually understands the principles knows that the differences between space and air flight do not obscure the fact that both follow well-understood laws of physics. And it says a lot that we humans can use those laws to design a device to fly or otherwise operate in places we've never been or to do things that have never been done while still having confidence that it will work. That's what science and engineering are all about.

[JayUtah]

An aircraft relies on air to manoeuvre...

Three-axis control is still the theoretical basis of all flight, whether in atmosphere or not.  If you can't figure out how a spacecraft achieves three-axis flight control, then you're just too ignorant to have this discussion.

I think you’ll find that I’m only one among millions of people who would find it absurd that the plans to build a working Rover, LM and Saturn V rocket are nowhere to be found...

Except that they are to be found.

Can you even begin to imagine what it would be like to be sworn to secrecy by your government...

Yes.

...because I certainly can?

No, you're just a troll making stuff up to get attention.  You clearly have no relevant knowledge or understanding.

By your own admission you are not one of the more “educated” members on here, and it shows, which is a good thing as you still have a chance to free yourself from the shackles of your indoctrination...

Nice dodge.  He asked you to put up or shut up, and you did neither because you don't actually know what you're talking about and don't want that fact made evident.  If all you can do is bluster about "indoctrination" while avoiding any meaningful test of your understanding and skill, then no one is obliged to listen to your drivel.

...if you’re incapable of looking up gravity equations, then you aren’t deserving of my attention.

What does the rest of this forum have to do be similarly undeserving of your attention?