How does propulsion in space work

[Munter]

speedtwelve said:

A good analogy is wearing a pair of skates and throwing a brick away from you; you'll move in the opposite direction to the throw. As mentioned, same principle as a mass of gas being ejected from a propelling nozzle; it doesn't need to 'push' against anything.

That doesn't help when people think the brick is pushing against air, with you pushing the brick. Remove the air from their (bonkers) theory, and the theory doesn't work. Hence them asking the question.

[kowalski655]

V8LM said:

That's not right. When I fart people move away from me rather than me move forward. Or is this relativity?

That's chemistry,not physics

Edited by kowalski655 on Wednesday 8th March 17:18

[Toaster]

Im not a great fan of same old Technology being repackeged as being new, and those who get irritated with me know that some of these new space rocket manufactures are just packaging existing technologies, utilising existing research and buying in technologies and along with great Marketing promise a Bright new future.

But what about alternate technologies, the ones that are realy going to make the step change

R&D in EM technologies is coming along and stand Einstein's theory of special relativity on its head......Don't believe me well have a read

http://arc.aiaa.org/doi/10.2514/1.B36120

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa....

If your having trouble with reading the papers (no disrespect to anyone) National Geographic have produced a nice article

http://news.nationalgeographic.com/2016/11/nasa-im...


'According to the team, the electromagnetic drive, or EmDrive, converts electricity into thrust simply by bouncing around microwaves in a closed cavity. In theory, such a lightweight engine could one day send a spacecraft to Mars in just 70 days'

[V8LM]

Munter said:

speedtwelve said:

A good analogy is wearing a pair of skates and throwing a brick away from you; you'll move in the opposite direction to the throw. As mentioned, same principle as a mass of gas being ejected from a propelling nozzle; it doesn't need to 'push' against anything.

That doesn't help when people think the brick is pushing against air, with you pushing the brick. Remove the air from their (bonkers) theory, and the theory doesn't work. Hence them asking the question.

Ask the luddites to try with two different mass but equal size bricks.

[Gary C]

Toaster said:

Im not a great fan of same old Technology being repackeged as being new, and those who get irritated with me know that some of these new space rocket manufactures are just packaging existing technologies, utilising existing research and buying in technologies and along with great Marketing promise a Bright new future.

But what about alternate technologies, the ones that are realy going to make the step change

R&D in EM technologies is coming along and stand Einstein's theory of special relativity on its head......Don't believe me well have a read

http://arc.aiaa.org/doi/10.2514/1.B36120

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa....

If your having trouble with reading the papers (no disrespect to anyone) National Geographic have produced a nice article

http://news.nationalgeographic.com/2016/11/nasa-im...


'According to the team, the electromagnetic drive, or EmDrive, converts electricity into thrust simply by bouncing around microwaves in a closed cavity. In theory, such a lightweight engine could one day send a spacecraft to Mars in just 70 days'

WOW

1mN per kW

Amazing !

[Zad]

Regarding the EM drive, have you seen any of the debunking videos? The maths is relatively simple. It takes 1GW (one thousand megawatts) just to lift a human off the ground. Assuming it is a genuine effect, which at the moment, it doesn't seem to be.

https://www.youtube.com/watch?v=jCAqDA8IfR4

[Einion Yrth]

Zad said:

Regarding the EM drive, have you seen any of the debunking videos? The maths is relatively simple. It takes 1GW (one thousand megawatts) just to lift a human off the ground. Assuming it is a genuine effect, which at the moment, it doesn't seem to be.

https://www.youtube.com/watch?v=jCAqDA8IfR4

I follow this a bit, that thunderfoot video is not terribly well respected. The evidence as presented by people who I believe to be honest brokers is interesting. Not yet to my mind adequate to declare it a real effect, but interesting enough to continue research, which for the most part they're doing on their own dollar. "The maths is relatively simple", well if it is accepted that it's a photon rocket, yes it is, they're st; the hypothesis however is that it isn't a photon rocket and if it isn't we'll need new physics to explain it, if it's real, natch. That's where it would become extremely interesting, and possibly useful. Next couple of years should tell us if it's real or not; I'm not prepared to write it off just yet.