Try to win my Challenge instead - see post #1. Explain how you fly to the Moon and back, and I send you 1M.

Heiwa --- Quote ---43000 kg is the mass of the space ship at arrival according NASA.

**Evidently it changes when fuel is consumed - but I keep it constant...**--- End quote ---

*Then you did the problem spectacularly wrong. You cannot pretend using the wrong propulsion model will give you the right answer. The mathematical management of the variable-mass property of a space vehicle is what separates the real engineer from the incompetent amateur. A real engineer can derive the mass changes based on the known properties of the propulsion system, or the change in the dynamic state (accurately, including the change in mass) based on the known expenditure of propellant. The fact that you can do neither, and don't even try, indicates you don't know what you're doing. Your oversimplification is fatal to your claim.*

Until you demonstrate even minimal competence, there is no point dissecting the rest of your "presentation" in depth.Heiwa --- Quote ---as NASA cannot inform how much fuel or energy was consumed to reduce the speed from 2400 to 1500 m/s to get into orbit.

--- End quote ---

*Factually false. Detailed pads for all burns have been available for more than 10 years. Someone so inept in his research does not enjoy a priori credibility. You bear the burden to prove you have solved the problem correctly, and you frankly admit you have not. It is not the job of your critics to educate you properly in the correct principles of spacecraft dynamics. You have claimed to be an expert. You will either therefore demonstrate expertise to our satisfaction, or you will be dismissed.*Heiwa --- Quote ---FGS, just read my presentation where all info is given.

--- End quote ---

*Your presentation is undocumented and proceeds from false premises and pretenses that I have outlined and asked you to correct here. Until those are corrected here, you have no reason to compel others to read a lengthy page of nonsense. Your egregious mistakes are made early enough on that the rest of your "presentation" is nonsense.*--- Quote from: Heiwa on December 28, 2012, 11:38:49 PM ---No, I use the correct, but simple, equations...

--- End quote ---

*No. You simplified away the most important part of the relevant equations -- the terms that deal with the change in spacecraft mass as fuel is consumed. Use the correct equations.*

There are no "my" equations; there are only the proper equations. Your "simplifications" based on your obviously limited knowledge of astrodynamics do not suffice. I've given you the hint: you must consider the natural logarithm of the ratio of start and end masses.

I will not spoon feed you information that you should know according to your claim to be an engineer. You have the burden to show you know what you're talking about. I will give you a reference however to Sutton and Biblarz as authors of some note on the subject. Reconcile your claims with the first few chapters in any of their books and return here.

No. By your own admission the spacecraft is a variable-mass vehicle, and you have specifically omitted that property in your computations. You have already admitted that you are using a simplified model, not a correct model. Either use the model you know you to be correct, or perform an error analysis to show that the difference between the correct model and your simplification is insignificant.

Even if using 1/2 m v2 was right (it's not) you have done the operations in the wrong order to get your answer. You have calculated delta(v2) when it should be (delta v)2

You really don't see the difference between

2400^2 - 1500^2 = 3,510,000

And

(2400-1500)^2 = 810,000

Because that is but one error you have made.

Or that the mass changes as fuel is used?

Also, I will require proof that you are prepared to pay one million Euros on demand or else this conversation will not proceed. Please deposit the sum in escrow in a bank of your choice and post its account number here along with the name of the escrow agent, and (in a private message) the PIN to verify the amount.What a spectacular fail...To be expected by a bot.