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Genergo: Propellantless space-propulsion system

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Re: Genergo: Propellantless space-propulsion system

#61

Post by anonymousiam »

Sanzig wrote: post #55
anonymousiam wrote: post #52

Torque rods are not a new thing. Lots of LEO spacecraft use them. They don't work for MEO/GEO because Earth's magnetic field decreases 1/R^3. https://en.wikipedia.org/wiki/Magnetorquer

Torque rods do work in MEO/GEO, but you need significantly more magnetic moment to get the same torque (ie: larger rods and more current). It's more a question of how much momentum you need to dump that determines if they are practical or not - magnetorquers are rarely used for direct attitude control, since they don't produce much torque. Instead, they are used "dump" excess momentum stored in the spacecraft's react…

Okay. They "work", but far less efficiently.

They're sometimes used on small/micro sats that don't have any reaction wheels or CMGs.

Solar sailing (pitching the solar panels) is another (and more "free") way to dump momentum by using the solar wind. Obviously you need a big solar array for this to be practical.

Re: Genergo: Propellantless space-propulsion system

#62

Post by amluto »

beloch wrote: post #22

Satellites once used propellant for attitude control. When the propellant was used up, the satellite lost the ability to maintain or change orientation. Very much as this article describes, control moment gyroscopes took over because they didn't require propellant. They operate on the same principles that let a cat land on it's feet by twisting about as it falls. However, there's a key difference between attitude con…

It’s surely hogwash. I like how it’s “validated” but does not mention power consumption or measured thrust.

For what it’s worth, one can very straightforwardly produce thrust using electromagnetism: just shine any sort of light out the back of your spaceship. This is called a photon rocket, and it works because light has momentum. Very little momentum: thrust = power / c. It’s only worth doing if energy is free in the way that light hitting a solar sail is free or if you power it with something absurdly energy-dense like antimatter.

Re: Genergo: Propellantless space-propulsion system

#63

Post by mikewarot »

It's easy to validate this claim, just link to its orbital tracking data.

I keep looking at the data for OPT-2[1] which is supposed to be a "quantum drive" from a IVO Ltd.[2] but haven't seen any significant orbital changes yet.

[1] https://celestrak.org/NORAD/elements/graph-orbit-data.php?CA...

[2] https://ivolimited.us/

Re: Genergo: Propellantless space-propulsion system

#64

Post by DarmokJalad1701 »

ravi-delia wrote: post #59
beloch wrote: post #22

Satellites once used propellant for attitude control. When the propellant was used up, the satellite lost the ability to maintain or change orientation. Very much as this article describes, control moment gyroscopes took over because they didn't require propellant. They operate on the same principles that let a cat land on it's feet by twisting about as it falls. However, there's a key difference between attitude con…

Propellant is still used for rotation control. Reaction wheels can "saturate" if they compensate for rotation more in one direction than the other on net, so propellant is needed to get them back down. Ion engines, generally speaking, do not use background dust. They still carry propellant, they just eject it electromagnetically. An photon engine, basically just a laser pointed backwards, uses pure electricity to pro…

> Reaction wheels can "saturate" if they compensate for rotation more in one direction than the other on net, so propellant is needed to get them back down.

Torque Rods can be used to desaturate wheels without needing any propellant

https://en.wikipedia.org/wiki/Magnetorquer

This is widely used in smaller satellites operating in Earth orbit.

However, this doesn't mean that TFA isn't BS.

Re: Genergo: Propellantless space-propulsion system

#65

Post by octaane »

jiggawatts wrote: post #51

"Scientifically tested!" is the marketing term for "The tests showed it didn't work, but we won't mention that second part!" E.g.: "successfully flight-tested" -- didn't break or leak anything when launched into space. A brick also has these properties. "validated across three space missions" -- a brick could be flown multiple times too, this proves nothing except that this thing is space-rated. "protected by a portf…

Yeah, this is exactly the lens that I was reading their release through. Seemed like a bunch of careful weasel word phrases.

Re: Genergo: Propellantless space-propulsion system

#66

Post by anon291 »

api wrote: post #43
Sanzig wrote: post #18

I am highly skeptical. A reactionless thruster is the holy grail of propulsion systems, but there are no known physics which permit it to work. A photon rocket would allow momentum exchange without mass consumption, but a quick look at the math shows it would be infeasible (hundreds of megawatts per newton). My guess is this works at all, it is inadvertently expelling reaction mass somehow, such as ablating off small…

A photon rocket would involve use of mass. The only conceivable way to power one would be something like fusion or antimatter matter annihilation, which converts mass into energy. It’s just a rocket with the maximum possible exhaust velocity: c.

Photons have no mass. Massive particles cannot travel at c. Massive particles experience time. Photons have momentum because they contain energy, but no mass. Momentum being expelled is how the mass is accelerated. You don't need a propellant, but you do need a means of generating momentum.

Re: Genergo: Propellantless space-propulsion system

#67

Post by verzali »

jiggawatts wrote: post #51

"Scientifically tested!" is the marketing term for "The tests showed it didn't work, but we won't mention that second part!" E.g.: "successfully flight-tested" -- didn't break or leak anything when launched into space. A brick also has these properties. "validated across three space missions" -- a brick could be flown multiple times too, this proves nothing except that this thing is space-rated. "protected by a portf…

I've been involved in enough futile in-orbit demonstrations to say everything here is absolutely correct.

Re: Genergo: Propellantless space-propulsion system

#68

Post by IshKebab »

yreg wrote: post #44
IshKebab wrote: post #37

Earlier quoted context omitted.

Classic perpetual motion using magnets nonsense. Are there really that many gullible people on HN?

> Are there really that many gullible people on HN? Who's gullible? Pretty much all of the comments show skepticism, but some are curious what is this about.

They are now, but when this was posted they were more like...

> Anyone have a clue how this might work?

> This is amazing. I wonder how it works. I would be cool if they published it.

Re: Genergo: Propellantless space-propulsion system

#69

Post by jerome-jh »

verzali wrote: post #32
Terr_ wrote: post #16

My money's on fake woo-woo. At first—like many others here—I thought it might just be a terribly-written explanation for a device that uses Earth's magnetic field, so that the planet itself is the "reaction mass" being pushed around... but I'm not seeing that in a quick patent search for the company. Instead, there's a bunch of stuff that seems like perpetual-motion-machine crankery, where their "motor" depends on a…

I think you are right. Either they have accidentally used the Earth's field somehow, or they are mistaking other effects (drag, perturbations...) for a thrust.

I would tend to think it uses Earth's magnetic field. Magnetizing or demagnetizing a moving mass would make its potential energy vary inside Earth's magnetic field. This may occur without reaction (I am not sure about this, my physics courses are far away and magnetic material physics is not that easy). Once they varied the potential energy of the moving mass, they would actually move it inside Earth's magnetic field, leading to a reaction force. The reaction force would be greater in one direction because of the cyclic magnetization/demagnetization.

Re: Genergo: Propellantless space-propulsion system

#70

Post by jerome-jh »

jerome-jh wrote: post #69
verzali wrote: post #32

Earlier quoted context omitted.

I think you are right. Either they have accidentally used the Earth's field somehow, or they are mistaking other effects (drag, perturbations...) for a thrust.

I would tend to think it uses Earth's magnetic field. Magnetizing or demagnetizing a moving mass would make its potential energy vary inside Earth's magnetic field. This may occur without reaction (I am not sure about this, my physics courses are far away and magnetic material physics is not that easy). Once they varied the potential energy of the moving mass, they would actually move it inside Earth's magnetic field…

And if the satellite's orbit is not perfectly circular, you may even be able to gain altitude by moving a mass at specifics times, like a kid on a swing or a skater in a ramp.
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