What does a rocket push against in space?

I can't believe that threads like this one still pop up.

Let look at an actual rocket engine and go through the numbers.

The NK-33 was designed by the Russians in the 60ies. It has a vacuum thrust of 1680 kN. How does it achieve this thrust?

It is generating a #load of very hot gas and letting it escape trough a nozzle. The nozzle converts gas pressure to gas velocity. Why is it important? Because mass times velocity is momentum. And change of momentum is thrust. So you want the gas to leave with as high velocity as possible.

So how much gas does the NK-33 generate? A whopping 517.44 kg per second. And this gas leaves the exhaust at 3.25 km/s.

It is essentially throwing 517 kg mass with a speed of 3.25 km/s out of its exhaust every second!

517.44 kg/s * 3.25 km/s = 1680 kN of thrust.

You can do the same calculations for any other rocket engine out there.

a reply to: moebius

the level of scientific illiteracy displaced [ often proudly ] online baffles me

its on thing to be clueless sat in a 17th century cottage illuminated by candles where the only books you can afford to own = a bible and a farmers almanac

but in 2019 - when you has an ATS account - i suspect the real reason would require T&C prohibited insults

^awesome! only proof of propellant propulsion in vacuum of space is some ~50 years ago grainy obscure sci-fi moon landing/docking proof and no more ever since even though ~40K other rockets since? progress!

deny ignorance, folks.

a reply to: Artesia

and we are done - ATS member Artesia is a grade 2 troll

the goalposts have moved

its not hear to learn or discuss the topic - its just < cencored >

a reply to: Artesia

youtu.be...

here is video from a live feed of an ignition occurring in space.


youtu.be...
and another second.

youtu.be...
and a third.

youtu.be...
and a fourth.

youtu.be...
and a fifth.

youtu.be...
and a sixth.

I think the point is proven. All of these were live streamed.

a reply to: dubiousatworst

Claim that those are fake/CGI in 3...2...1.....

originally posted by: Artesia
^awesome! only proof of propellant propulsion in vacuum of space is some ~50 years ago grainy obscure sci-fi moon landing/docking proof and no more ever since even though ~40K other rockets since? progress!

deny ignorance, folks.

Deny what ignorance? That you don’t understand high school physics? Or the satellites that bring you GPS, live news feeds, and cable feeds? Satellite phones? Or the live images from various space missions? Or the civilian component of rocketry?

a reply to: neutronflux

You’ve only taken high school physics? Lol 😂

a reply to: moebius

That my friend is caused by pressure gradient force and not because the rocket is pushing it out.

originally posted by: NicSign
a reply to: neutronflux

You’ve only taken high school physics? Lol 😂

No, you are the one that cannot grasp high school physics.

Again.
Think about it this way. A shotgun shooting a blank cartridge will still kick. Is that a false statement. How is a shotgun that kicks any different than a very short duration rocket?

If you don’t think a shotgun would kick in a vacuum, Using Newton’s third law show why.

originally posted by: NicSign
a reply to: moebius

That my friend is caused by pressure gradient force and not because the rocket is pushing it out.

Define pressure gradient force my friend, and calculate the thrust of the NK-33 using it please.

originally posted by: NicSign
a reply to: neutronflux

You’ve only taken high school physics? Lol 😂

And I suppose you are a rocket scientist? I hope you did not pay for your education, if you did you might want to claim your money back.

OK here are a couple of links for the uneducated re satellites and space in general

Hi-Res Imaging

Here is some video using this tech.

a reply to: wmd_2008

That won't work - he will stick his/her fingers in ears and shout "Fake/CGI".

a reply to: tinymind

Thats very clever but you need resistance against the thrust bacic physics. Thats why space probes fire engines to bank or turn off a planets gravity field for a new trajectory to another planet. Thing cant turn from resistance off its own body needs another independent body or force

I've been off planet for nearly a week and this threads still going. Too funny.

a reply to: wmd_2008

Are you sure it’s just not an aerial photograph form a plane or helicopter?

a reply to: moebius

Pgf= 1/density*difference in pressure.

So if you can give me a figure of how much pressure is built up in the rocket chamber, I can calculate it for you.

a reply to: oldcarpy

Well if you only high school physics and haven’t taken fluid dynamics, you may not fully understand. So therefore you are vulnerable to what people tell you to believe because you don’t know better

This might help old but good physics!

Simple Physics