# Microwave drive for cubesats

Theory: how is this?

I was doing a lot of research about the EmDrive thruster, i find 50% papers says that it work and other 50% saying that the "thrust" is a product of the interaction with the magnetic field of the Earth. I also see this, EmDrive on cubesats?? And then i think, a 3U cubesat with very big solar array, can drive that cubesat from LEO to Moon orbit?

Thanks for any clarification.

• – uhoh Oct 19 '20 at 13:31
• There are several reasons to post links to related questions. The important one is to link them permanently so that people on this page will see the others (in the linked section) and people on those pages will then see your newer question which is a good thing, right? I don't know what that paper says nor if it is worth reading, but a website called "emdrive.com" is automatically a non-authoritative source in my book! What are they selling? – uhoh Oct 19 '20 at 13:36
• My brain is hurting, but a read through suggests it is a legit(ish) drive, but not en EM reactionless drive, it is getting thrust by radiating microwaves en.wikipedia.org/wiki/Photon_rocket with the pros and cons there. Which does not match the graphs and listed powers in the article. So I think we have two different things being called "EM' which is probably not helping work out what is going on – GremlinWranger Oct 19 '20 at 13:53
• @GremlinWranger see answer below, have I got it wrong or is this still a momentum non-conserving unicorn? It looks exactly like the Em Drive hocus pocus sealed, high-Q microwave cavity that mysteriously generates thrust for no good reason. – uhoh Oct 19 '20 at 14:16
• @ValentinoZaffrani and like gas pressure, photon pressure on the inside of a closed container produces no net force. EmDrive is based on the sort of misunderstanding that would predict that a pressurized soda bottle would accelerate toward its base because the base has more surface area than the cap. – Christopher James Huff Oct 19 '20 at 14:35

This is the same or similar unphysical stuff as before.

Then for 40W power inside cavity, the calculated Thrust T=20.44mN.

There is no propellant here. If 40 Watts were in the form of photons, then the thrust would be $$P/c$$ = 133 nanoNewtons. This generates 105 more momentum per unit time that it's allowed to.

What's the final word; does the EmDrive drive work or not?

It continues to work generating cash and website clicks and dreamy hope that interstellar flight could be achievable, and seems to be more successful than Mars One in doing that kind of... of... what's a good word for it?

What is was Mars One?

From this answer to Are they building on mars or do they have a camp there?

As everyone knows, the best way to check to see if something is a scam is to see if it has a website.

Lets see how long non-conservation of momentum can hold out!

• @ValentinoZaffrani I think this is totally impossible, as do most people. It violates conservation of momentum. Why is the “impossible” space drive impossible? – uhoh Oct 19 '20 at 15:32
• And for those who for some reason believe it's somehow "more okay" to violate conservation of momentum than energy: it violates conservation of energy too. In emdrive.com/2Gupdate.pdf Shawyer explicitly claims the drive acts as a reversible electrical machine that will transform acceleration to power. This means you could just sit one on one end on the ground and have it constantly generate power from gravitational acceleration. (Shawyer makes numerous mistakes which make it clear he doesn't understand the equivalence principle.) – Christopher James Huff Oct 19 '20 at 16:12
• So the final word is: NO, the EmDrive dont generate thrust. Thanks to all – Valentino Zaffrani Oct 19 '20 at 16:55
• @ValentinoZaffrani On the experimental side, there's no clear evidence that it produces thrust, every improvement in measurement reduces the amount of thrust it might produce. On the theory side, there's no theoretical reason to think it should produce thrust, and very strong theoretical reasons to think that no such device can do so. The justifications for it are severely flawed: Shawyer clearly doesn't understand relativity, White's quantum vacuum nonsense is just technobabble...quantum vacuum fluctuations are not a plasma. – Christopher James Huff Oct 19 '20 at 21:39
• @ValentinoZaffrani basically, it's as likely to produce thrust as any other random contraption thrown together from spare parts. That doesn't mean it doesn't produce thrust, but it'd be a miraculous coincidence if it did. It's not a productive approach to developing spacecraft propulsion. At best, if reactionless drives actually are possible, it's almost certainly a distraction from whatever mechanism actually allows them. – Christopher James Huff Oct 19 '20 at 21:43