Pokrovsky theory

[mcclellan]

Here is another and independent method of velocity calculation for Apollo 11 in connection with the separation of stage 1 after 162 seconds (Phil Pollacia, Alexander Popov and Stanislav Pokrovsky have nothing to do with it).

First of all, here is the analyzed NASA official video (a tracking camera):

www.footagevault.com/clip/FTV-0005365

The image frequency is 24 fps (NASA:s own data, you can see it if you follow the link above).

And here is the analysis itself (first a series of still images):

supernovum.ru/forum/read.php?2,302361







Then the images were placed in layers in other to determine the distance based on the known rocket length:



Below is an animation of these still images:



Finally we got this picture (with explanations and different markings):



The summary: this series of five still images shows that the rocket moves 324 pixels between the two red dots in four frames. The rocket is 170 pixels long, which means that 324 pixels corresponds to 210 meters. In 1 second (i.e. after 24 frames), the distance would be 1260 meters, i.e. the vellocity of Apollo 11.

Then, a similar calculation was made for a moment just after the separation of stage 1:



Which gave the following result:



The rocket moved 318 pixels in four frames (the distance between the two red dots in the gas cloud behind). The rocket's length has been measured to 172 pixels, which means that 318 pixels corresponds to 204 meters in four frames. After 24 frames (i.e. after 1 second) the distance would be 1224 meters.

The person behind this analysis (SEVER NN) says that even if the frame rate had been 30 fps (but it isn't!) it would still mean that the velocity would have been only 1680 m/s, which in any case would not have been sufficient to achieve NASA's declared 2400 m/s after 162 seconds.

The conclusion based on this method is that the rocket moves at 1224-1260 m/s 162 seconds after lift-off, i.e. only half the declared NASA velocity.

[Jason Thompson]

Having said that, if we assume uniform acceleration with the figures you provide:

Acceleration = change in velocity over time.

Initial velocity is zero, and according to you it is doing 104 m/s at 108 seconds. 104/108 = 0.96 m/s^2


The equation to work out distance travelled by an accelerating object is d = vt + 1/2 at^2

Where:

d = distance
v = initial velocity
a = acceleration
t = time

Since again v = 0 in the case of a launch, the equation simplifies to d = 1/2 at^2

The launch tower was cleared in 12 seconds from launch. Plug that in and:

d = 1/2 x 0.96 x 12^2

= 69 metres.

Clearly there is a problem there, because the launch tower is a lot higher that 69 metres tall. And yet it is indisputable that the vehicle had cleared it 12 seconds after liftoff. That is also a far more reliable estimate than measuring shadows on clouds, since the launch tower is a known height and is being observed face on.

In order to clear the tower in 12 seconds and yet be doing only 104 m/s after 108 seconds it must have had a higher acceleration in the early stages of the flight than it did later on, but that is entirely inconsistent with the behaviour of a fixed thrust rocket engine. It is also inconsistent with the idea of a low thrust Saturn V. The only way your scenario could be achieved is to have an engine that was capable of putting the rocket into orbit, but deliberately throttle it down part way into the flight (a capability, incidentally, that none of the engines except the LM descent engine actually had).


A question for the shaodw measuring: has anyone accoutned for the fact that the engine plume was itself opaque, and therefore, counter-intuitive as it might be seeing those bright flames, would have added to the length of the shadow on the cloud?

[Jason Thompson]

And the other analysis is taking features in a fluid exhaust cloud and treating them as though they were solid and, moreover, as if they are static references for the rocket. Why?

[mcclellan]

Oct 31, 2011 9:33:15 GMT -4 Jason Thompson said:

Having said that, if we assume uniform acceleration with the figures you provide:

Do not "assume" anything. Just take a look at NASA:s official video (footagevault) and make your own measurements. Perhaps you will understand a thing or two after that.

Just a little comment to SEVER NN:s method: the rocket "spits out" the flame and gases backwards, which certainly would add to the estimated velocity. So, his 1224-1260 m/s is probably too fast. Pokrovsky and Popov used three other methods and got (970 ± 50) m/s. Far from NASA:s 2400 m/s...

And when four different methods confirm each other, then we can no longer talk about a coincidence. In that case, we have hard facts that reveal NASA:s fake.

[mcclellan]

Oct 31, 2011 9:36:07 GMT -4 Jason Thompson said:

And the other analysis is taking features in a fluid exhaust cloud and treating them as though they were solid and, moreover, as if they are static references for the rocket. Why?

It's a qualified calculation and a good estimate, and this method has been validated on a Ares X-1 rocket launch with known velocity.

The fact that the gas cloud is fluid and moving (backwards!) is not to NASA:s advantage, quite the opposite so.

[JayUtah]

Oct 31, 2011 9:25:41 GMT -4 mcclellan said:

Then the images were placed in layers in other to determine the distance based on the known rocket length:

And this step is valid ... why?

The summary: this series of five still images shows that the rocket moves 324 pixels between the two red dots in four frames.

And the red dots represent a fixed reference ... how?

[JayUtah]

Oct 31, 2011 9:56:10 GMT -4 mcclellan said:

It's a qualified calculation and a good estimate, and this method has been validated on a Ares X-1 rocket launch with known velocity.

Show us this alleged validation.

The fact that the gas cloud is fluid and moving (backwards!) is not to NASA:s advantage, quite the opposite so.

The fact that you don't account for exhaust gas velocity (known or estimated) in the method makes it an invalid method.

[twik]

For this calculation to work, we would have to assume that the rocket moving is at *exactly* right angles to the camera the entire time. Is there any reason to assume that?

[JayUtah]

Oct 31, 2011 9:48:25 GMT -4 mcclellan said:

Do not "assume" anything.

I may certainly assume (a) the known fluid dynamics of a liquid-fueled rocket exhaust, (b) the known dynamics of the F-1 engine plume, (c) the plume creep behavior of the S-IC. I may assume them because they are known properties that pertain to my industry. To ignore them in a pertinent calculation, yet insist that the calculation is valid, would be folly -- especially when the result differs significantly from expectations.

Further, you don't seem to have accounted for the photogrammetrics of the problem. You assume you're seeing the rocket exactly from the side such that you can use linear measurements in image space as if they were true measurements in affine space. Why have you done this?

[Jason Thompson]

Oct 31, 2011 9:48:25 GMT -4 mcclellan said:

Just take a look at NASA:s official video (footagevault) and make your own measurements.

I did. The launch and the time taken to clear the tower. The only time in the entire launch footage when I know that I am watching the rocket mve against a fixed, solid reference and at a perpendicular angle to my viewing position. I don't need to measure pixels or clouds or anything like that, because I know that I am watching a solid rocket move vertically next to a solid gantry, and I know the heights of each of those things precisely.

Perhaps you will understand a thing or two after that.

I do understand enough to know that there are flaws in your two analyses that are not present in the launch example I gave.

Just a little comment to SEVER NN:s method: the rocket "spits out" the flame and gases backwards,

Relative to what? How do you account for the initial forward velocity that the gases have and the effect of impinging on a dynamic fluid once they exit the nozzle?

You have only to look at the footage to see how flawed the idea is, because at least some of that high velocity rocket exhaust from those engines, despite being blasted out the back at high speed in a direction opposing the rocket's motion, actually flows up the side of the rocket to about half the length of the first stage. In other words, for a portion of time it actually moves in the same direction and faster than the rocket itself.

The analysyes you have presented oversimplify the reality of the situation to the point when they are simply not applicable.

And when four different methods confirm each other, then we can no longer talk about a coincidence.

You're right: it's not a coincidence that all four methods suffer the same basic flaws to begin with.

In that case, we have hard facts that reveal NASA:s fake.

No, we have poor analyses based on false premises and which give results contrary to rather more fixed examples (the launch tower clearing) and to the known behaviour of rockets.

[mcclellan]

Oct 31, 2011 10:04:17 GMT -4 twik said:

For this calculation to work, we would have to assume that the rocket moving is at *exactly* right angles to the camera the entire time. Is there any reason to assume that?

This is a common misconception. The angles have nothing to do with this doing. The rocket's visible length and the clouds behind are in the same line, which means that the proportions remain.

Take a look here:



Do you agree with that?

[mcclellan]

Oct 31, 2011 10:23:32 GMT -4 Jason Thompson said:

Oct 31, 2011 9:48:25 GMT -4 mcclellan said:

Just take a look at NASA:s official video (footagevault) and make your own measurements.

I did. The launch and the time taken to clear the tower.

Did you? I asked you to watch this video ...

www.footagevault.com/clip/FTV-0005365

... and make measurements from it.

And you start talking about a completely different video. Try to stick to the topic rather than jumping back and forth as you do.

[Jason Thompson]

I am sticking to the topic. I am not making measurements from that video because I do not believe the method you describe is valid. Will you please explain why the use of the tower clearing at launch is invalid in a discussion about the acceleration of the rocket?

[JayUtah]

Oct 31, 2011 10:23:58 GMT -4 mcclellan said:

This is a common misconception. The angles have nothing to do with this doing. The rocket's visible length and the clouds behind are in the same line, which means that the proportions remain.

Congratulations, you just committed the most basic error of photogrammetry -- assuming that distance-varying measurements remain in proportion. That's the single biggest "gotcha" of projective geometry.

Do you agree with that?

Not in the least. In fact, it reveals that your "analyst" is very much an amateur.

In addition to committing the most common general error, your analyst has also committed a specific error by assuming that the plume edge is parallel to the rocket axis and/or to the direction of travel.

We cannot accept this analysis until you have provided a valid photogrammetric solution.

[Jason Thompson]

Oct 31, 2011 10:23:58 GMT -4 mcclellan said:

Do you agree with that?

No. The plume is quite clearly expanding on exiting the engines, therefore the features identified in the exhaust plume are NOT moving in the same line as the rocket at all.