Author Topic: Faking the moon landings  (Read 16080 times)

Offline JayUtah

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Re: Faking the moon landings
« Reply #420 on: February 12, 2019, 03:17:34 PM »
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.

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...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."
"Facts are stubborn things." --John Adams

Offline benparry

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Re: Faking the moon landings
« Reply #421 on: February 12, 2019, 03:56:11 PM »
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.



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...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

Offline Peter B

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Re: Faking the moon landings
« Reply #422 on: February 13, 2019, 08:01:36 AM »

[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?

Offline JayUtah

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Re: Faking the moon landings
« Reply #423 on: February 13, 2019, 09:22:10 AM »
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.
"Facts are stubborn things." --John Adams

Offline Echnaton

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Re: Faking the moon landings
« Reply #424 on: February 13, 2019, 07:44:40 PM »
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.
The sun shone, having no alternative, on the nothing new. —Samuel Beckett

Offline Glom

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Re: Faking the moon landings
« Reply #425 on: February 14, 2019, 07:22:16 AM »
I still cannot believe this guy is getting responses. He is clearly a troll...

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

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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.

Offline benparry

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Re: Faking the moon landings
« Reply #426 on: February 14, 2019, 09:11:15 AM »
I still cannot believe this guy is getting responses. He is clearly a troll...

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

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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

Offline gillianren

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Re: Faking the moon landings
« Reply #427 on: February 14, 2019, 11:32:07 AM »
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.
"This sounds like a job for Bipolar Bear . . . but I just can't seem to get out of bed!"

"Conspiracy theories are an irresistible labour-saving device in the face of complexity."  --Henry Louis Gates

Offline JayUtah

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Re: Faking the moon landings
« Reply #428 on: February 14, 2019, 01:19:48 PM »
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.
"Facts are stubborn things." --John Adams

Offline Echnaton

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Re: Faking the moon landings
« Reply #429 on: February 14, 2019, 09:31:01 PM »

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.
The sun shone, having no alternative, on the nothing new. —Samuel Beckett

Offline AtomicDog

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Re: Faking the moon landings
« Reply #430 on: February 14, 2019, 11:10:16 PM »
Now cambo is just repeating himself.
"There is no belief, however foolish, that will not gather its faithful adherents who will defend it to the death." - Isaac Asimov