So, who wants to win 1 million Euro?

[Heiwa]

Then use it and calculate the energy required to slow down in space.

This was done for you pages ago.

Just be polite and use proper language, as my Mother always says.

You are not the moderator, and you are the worst offender for politeness.  You are calling me and my profession liars and are libelling nearly everyone in connection with the aerospace industry.  You will therefore answer my questions and stop lecturing everyone on your misguided notions of politeness.

Yes, I am not a moderator. I was just quoting my mother. BTW - how much fuel was required to slow down Apollo 11 to enter Moon orbit? I missed that one.

[Jason Thompson]

If you keep missing it i suggest you go back and read the thread. It has been answered already.

[ka9q]

Good, what is the SFC in kg/s or kg/hr of a P-22KS propulsion rocket engine with 97 400 N thrust in space?

It uses a mixture of nitrogen tetroxide and hydrazine fuel. I am just interested in the kg/s or kg/hr figure.

Pls provide link, etc.

You have already been provided links to all the material. I gave them to you myself.

But just to give you even more rope to hang yourself with, here's a spoon-fed derivation.

As others have explained, the SPS on the Apollo CSM uses the AJ10-137 engine with a nominal thrust of 91 kN. Where did you get "P-22KS" and 97 400N?

The SPS has a rated I_sp of 314 seconds. Multiply that by the acceleration of gravity (9.080665 m/s^2) to get the effective exhaust velocity: 3079.3 m/s. Therefore, the propellant mass flow rate for a thrust of 91 kN is simply

91,000 N / 3079.3 m/s = 29.55 kg/s

Très simple -- when you actually know some basic rocketry.

 

[ka9q]

BTW - how much fuel was required to slow down Apollo 11 to enter Moon orbit? I missed that one.

No, you didn't miss it. You simply ignored it.

[Chew]

Do you know what the Tsiokovsky equation is?

Yes! Has nothing to do with slowing down in space.

Bwahahahaha! Oh, man, that is hilarious. Do you really think the fuel is conscious and self-aware and knows which way it is being expelled relative to the direction of travel?

[Andromeda]

As others have explained, the SPS on the Apollo CSM uses the AJ10-137 engine with a nominal thrust of 91 kN. Where did you get "P-22KS" and 97 400N?

Jason and I have done some sleuthing.  The only reference we can find to this is the schematic on page 405 in "Stages to Saturn" by Roger E Bilstein*.  Jason has just gone to grab the book, he will be back in a minute.  We suspect an inaccuracy in the text, given that it matches up with nothing else Apollo.



* apart from on Heiwa's own website.

[Jason Thompson]

Yup, there it is, on page 405. A schematic with, annoyingly, no citation as to when it was made or by whom. Since I can find no other reference to the SPS using anything other than an AJ10-137 engine, I find it rather curious.

[raven]

Lucky for the rest of us without such an extensive library, the rest of us can also examine this source thanks to Google Books.

[stutefish]

The interior of the Apollo 11 command module would soon be heated up to 200°C early at the re-entry and the cosmonots would be burnt to death prior the whole space ship would disappear in smoke. Not even a Finn would manage it.

Am I the only one excited by the idea of what a motivated Finnish space program could accomplish?

[Heiwa]

The math has been explained to you here, and you have received copious references to the available published figures and the century-old methods for applying those figures.  You simply ignore them.  It is no great secret; it's published in books freely available to all, a reference to which I provided pages ago.

Yes, I agree all is very easy - to slow down a heavy (43 000 kg)  space ship in space from one high speed to another, little lower high speed, you apply a substantial force on it (eg 97 400 N), e.g. by using a 1960's rocket engine. The rocket engine consumes fuel in order to slow down the space ship. What is the fuel consumption (kg/s) to produce a certain force (N). According my calculations one kg fuel can produce 1.63 MJ energy to produce the required force. 

It is not very efficient = more fuel is needed than can be carried, it seems.
 
Applied to a seagoing ship means that the ship sinks prior departure. Not very nice.

Imagine a 43 tons car on your door step. Imagine the engine you need to accelerate this heavy car to 2 400 m/s speed. It will be quite big. And now you want to brake from 2 400 to 1 500 m/s speed using a brake. You agree it is a big brake.

Or take the Shuttle - about 78 tons - flying at 7 800 m/s speed around the Earth at 400 000 m altitude to/from the ISS. To slow down for going back to Earth, the Shuttle is turned around and the engines are on full blast but the only result is that the altitude becomes lower and the speed increases to 9 000 m/s at 150 000 m altitude ... while you are still going backwards. You are flying backwards! How to stop?
It is not possible. Not even a computer can land the Shuttle. But Captain Mark Kelly managed to do it. I explain how in my presentation. Enjoy. 

[Jason Thompson]

You can keep saying your wrong equations as much as you like, Heiwa. The fact remains that you are using the WRONG principles to apply to a rocket. You have NOT accounted for the variable mass. you have NOT accounted for the expulsion of mass from the back of the rocket. you have oversimplified it to a kinetic energy problem and totally failed to appreciate the correct requirements for a space system. And this is despite the number of times it has been explained to you. I've had more productive days banging my head against a brick wall, frankly.

[Andromeda]

You have been told the mass of fuel required so why do you ignore the answers and keep asking?

Show us your 1.63MJ/kg calculation or source.

Admit that spaceflight is nothing like sailing a ship, for reasons explained in depth.

Admit that "big" and "quite big" are useless concepts in physics - we need demand numbers.

Lastly, please enjoy this webpage: http://insti.physics.sunysb.edu/~siegel/quack.html

[Heiwa]

Where did you get "P-22KS" and 97 400N?

From NASA - references in my presentation - link in post #1. 

[Heiwa]

Show us your 1.63 MJ/kg calculation or source.

See link in post #1.

[Andromeda]

Where did you get "P-22KS" and 97 400N?

From NASA - references in my presentation. 

I am not going to waste my life reading your presentation.  Provide the source here, now.