Saturn V rocket needed to be 266 times bigger.

[JayUtah]

The rocket, the tank, and the fuel within it are in the same gravitational and inertial reference frame. There is no force drawing the fuel toward the earthward side of the tank in any orientation. The only inertial force acts toward the tail of the rocket, regardless of its orientation, so long as the rocket is under thrust.

To answer your other question, no -- there is no difference in the strength derived from pressure as the liquid portion of the fuel depletes. However, the center of mass shifts upward along the axis as the fuel depletes, and this makes the structure respond differently. The vibration and resonance of the structure changes as fuel is depleted. That can have an effect on the strength of the structure -- more accurately: it can identify flaws in the vehicle's structural design.

[PeterB]

G'day Margamatix

If, as you say, the Saturn V wasn't big enough to go to the Moon, what rocket brought back all those rocks? You've already said you accept the rocks are genuine Moon rocks, and you think they were collected by robot technology of some sort. Now you need to explain how those robots got to the Moon.

Cheers

[jovianmoon]

margamatix said:

Well, let's all hope that Apollo didn't happen, as I'm sure you would all be as nauseated as I would if America's first mission to the moon was masterminded by a Nazi war criminal responsible for the mass slaughter of civilians, who should have been hanged at Nuremburg......

Margamatix has now made a personal attack on von Braun (a transparent red herring) becuase he realises his inital arguments about the Saturn V rocket have been shown to be invalid. Unfortunately for Margamatrix:

(a) the posters on this forum who are aware of the reality of Apollo are not so easily distracted from the original null and void argument by this red herring and even if they were;

(b) the judgement that von Braun was Nazi 'war criminal' is not supported by even the most cursory investigation into his biography. A Nazi he was, yes. In fact he was eventually promoted to the rank of Sturmbannfuhrer (military equivalent: major) in the SS. This does not make him a war criminal. He was coerced into joining the NSDAP and the SS with the threat that if he did not do so his work in rocketry would be halted. His promotions were involuntary. He distained the use of rocketry for the destruction of civilian London and was eventually arrested by his own SS for being more interested in the (erstwhile) theory of space travel than in armaments. If his work on the V2 rocket is to be considered a 'war crime', then so too should the American developers of the atom bomb and the British planners of the mass bombings of German cities be considered war criminals. Personally, I do not consider them so, but that is a debate for a different thread on a different forum.

Cheers.

PS - this is my first post on this forum - so 'Hi' to all. I often posted regularly on BA as 'Jovianboy' a couple of years ago, but have only recently been back there... hope to get back into the swing of things at both sites.

Edit: Oops. I should have read the entire thread before posting a reply. I have just done so and reaised that others have already made the points that I have. Apologies for the repitition. That'll teach me...

[PhantomWolf]

Don't worry it's always good to have them reinforced as margamatix and his ilk seem to be totally deaf to anything tht doesn't say what they want it too.

Welcome to the board. Hope your stay is fun.

[Count Zero]

jovianmoon said:

He was coerced into joining the NSDAP and the SS with the threat that if he did not do so his work in rocketry would be halted.

These days, most of the arguments for von Braun being a war criminal are not based on the use of V-2s in combat, but rather where they were built. The underground factory used slave labor. People who use the phrase "hellish conditions" understate the depths of barbarity the Nazis reached at the Mittelbau-Dora concentration camp. Tens of thousands "foreign workers" were worked to death building and operating the factory - far more than were killed by the weapon's use.
The argument goes that von Braun knew about the conditions, and refused to speak out against them because his dreams of rocket flight were more important than the means to achieve them. This depraved picture is not supported by the historical record.
Von Braun allegedly did visit the camp and saw the conditions there. By this point, the design work on the A-4 (a.k.a. V-2) was essentially complete, and he was working on more advanced rockets. He was deeply ashamed of what he saw. Shortly thereafter, he was arrested for expressing sentiments that the war was lost, and that his rockets should be used for space travel and not war. His boss, General Walter Dornberger, obtained his release. He immediately started working with his staff on plans to surrender to the western allies. As one history told it,
"Most of the scientists were frightened of the Russians, they didn't think much of the French, and the British did not have enough money to afford a rocket program. That left the Americans. After stealing a train with forged papers, von Braun led 500 people through war-torn Germany to surrender to the Americans. The SS were issued orders to kill the German engineers, who hid their notes in a mine shaft and evaded their own army while searching for the Americans. Finally, the team found an American private and surrendered to him."

[Sticks]

Wow not only rocket science do we learn, but history as well

[Count Zero]

sticks said:

Wow not only rocket science do we learn, but history as well

That is why I love these boards so much. Yesterday I didn't know these things. Somebody writes something, and I get curious about the details and start digging, and that leads to other stuff...

I think it was Robert Heinlein who defined a "boring person" as one who opens an encyclopedia, finds what they were looking for, and then closes it and puts it away.

[Count Zero]

jayutah said:

The rocket, the tank, and the fuel within it are in the same gravitational and inertial reference frame. There is no force drawing the fuel toward the earthward side of the tank in any orientation. The only inertial force acts toward the tail of the rocket, regardless of its orientation, so long as the rocket is under thrust.

It's taken me a few days to chew on this. My experience is with riding on airplanes. At take-off, I feel both the engines' thrust and a downward pull which I associated with gravity. Am I correct that what I'm actually feeling is two force vectors, one from the thrust and one from the lift generated by the wings? In that case, I can understand the rocket [without wings] as having only one force vector - thrust.

jayutah said:

To answer your other question, no -- there is no difference in the strength derived from pressure as the liquid portion of the fuel depletes. However, the center of mass shifts upward along the axis as the fuel depletes...

(emphasis added)

You lost me again. Since the tanks are emptying from the top down, shouldn't the center of mass be moving down towards the engines?

jayutah said:

The vibration and resonance of the structure changes as fuel is depleted. That can have an effect on the strength of the structure -- more accurately: it can identify flaws in the vehicle's structural design.

The hard way?

[JayUtah]

My experience is with riding on airplanes.

That's not a ballistic scenario.

In that case, I can understand the rocket [without wings] as having only one force vector - thrust.

Yes.

Since the tanks are emptying from the top down, shouldn't the center of mass be moving down towards the engines?

That might actually be possible. It depends on the specific mass properties of the rocket. When the rocket's fuel has been depleted, but its payload is still attached (barring staging), the center of gravity is well forward. But that doesn't mean it moves there monotonically from its launch position.

jayutah said:

The vibration and resonance of the structure changes as fuel is depleted. That can have an effect on the strength of the structure -- more accurately: it can identify flaws in the vehicle's structural design.

The hard way? [/quote]

[Bob B.]

jayutah said:

They accurately quote from Von Braun's 1953 book, but unfortunately since Sibrel is not an engineer, scientist, historian, or in any way qualified to comment on space development history, he expects those alarming figures to stand on their own.

First, as has been said, Von Braun assumed a direct-ascent approach in a single spacecraft. …

Second, von Braun assumed the craft would have to be built with the V-2 structural technology he was familiar with. …

I have a couple questions for Jay or whoever else might know the answer.

First, what is the name of von Braun’s 1953 book?

Second, what fuel did von Braun base his calculations on? As we know, the Saturn V used liquid hydrogen in its upper stages. If von Braun’s calculations were based on a less efficient fuel, then this would have been another contributing factor.

[PhantomWolf]

I'd suggest that the book is Conquest of the Moon and if it was based on the V-2 then possibly ethanol/LOX?

I'll see if I can find more on that.

[Bob B.]

phantomwolf said:

I'd suggest that the book is Conquest of the Moon

Either that or perhaps Across The Space Frontier, though I think that was 1952.

phantomwolf said:

and if it was based on the V-2 then possibly ethanol/LOX?

That's what I'm thinking, particularly since he continued to use ethanol/LOX in the Redstone (first launched in 1953). The Redstone had a sea level specific impulse of only 235 s. If he used anything close to that figure it would surely contribute to his need for such an immense rocket. The appeal of liquid hydrogen as a fuel was certainly known in 1953 but the technology to use it had yet to be developed.

phantomwolf said:

I'll see if I can find more on that.

Anything you can find would be helpful. I need the information for an article I'm writing. I'll explain more later.

[reynoldbot]

Am I dense? I can't find the video Margamatix tried to link to. All I found was a link that said "replay intro" in which bart hassles an Apollo astronaut.

[grashtel]

reynoldbot said:

Am I dense? I can't find the video Margamatix tried to link to. All I found was a link that said "replay intro" in which bart hassles an Apollo astronaut.

The post is just over a year old, if you can't get at it its probably been taken down for some reason.

[captain swoop]

When the new mission goes to the moon with a rocket that isn't the size of the Empire State building, will they claim it's a hoax because it isn't big enough?