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Genergo: Propellantless space-propulsion system

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Re: Genergo: Propellantless space-propulsion system

#71

Post by K0balt »

octaane wrote: post #42

Not possible according to the laws of physics. The closest you can get is a solar sail, but that's not "propellant-less" - photons are the propellant. If a company thinks they've broken one of the most fundamental laws of physics (momentum transfer), they need to provide some serious evidence, and publish in full so their results can be replicated. A press release on an obscure website isn't how you do it.

Seems like the focus is on orbital dynamics, so I’m guessing it is reacting against the magnetic field of the planet or the particulates in the solosphere.

It would be cool, though, if it were actually interacting with the zero point field or some similar bunky stuff. We can already extract minute amounts of matter from the field, ostensibly experimentally proven, so I suppose it’s not impossible to imagine that you might somehow be able to push on Casimir forces, perhaps.

Re: Genergo: Propellantless space-propulsion system

#72

Post by api »

anon291 wrote: post #66
api wrote: post #43

Earlier quoted context omitted.

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.

Photons have mass in the sense that energy and mass are equivalent. What I meant is that a ship with a photon rocket is expending mass, given that the power requirements demand some kind of mass energy conversion to get enough photons. Viable photon rockets able to move anything of any size would require petawatts of power.

If you do the rocket equation math it kind of behaves like you are throwing mass at c even though you are not. You are converting mass to energetic photons and throwing them at c.

There’s a rough breakdown I saw once on a forum about future space flight tech:

Launch is dominated by thrust. Your T/W ratio must be >1. Travel within the solar system is dominated by specific impulse. Small thrust for a long time can get you going real fast, but you can only carry so much propellant. Interstellar flight or beyond is dominated by raw energy. To get to the stars in any “reasonable” time requires you to be doing a fair amount of E=mc^2-ing.

Re: Genergo: Propellantless space-propulsion system

#73

Post by ahazred8ta »

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 could be a legitimate conductive tether system. These have flown on the space shuttle and cubesats: see TEPCE and MiTEE.

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

But the 'pulses' make it sound like EmDrive hogwash.

Re: Genergo: Propellantless space-propulsion system

#74

Post by anon291 »

api wrote: post #72
anon291 wrote: post #66

Earlier quoted context omitted.

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.

Photons have mass in the sense that energy and mass are equivalent. What I meant is that a ship with a photon rocket is expending mass, given that the power requirements demand some kind of mass energy conversion to get enough photons. Viable photon rockets able to move anything of any size would require petawatts of power. If you do the rocket equation math it kind of behaves like you are throwing mass at c even tho…

> Photons have mass in the sense that energy and mass are equivalent

Mass and energy are convertible but not equivalent.

You are confusing momentum and mass, which are two different concepts.

Re: Genergo: Propellantless space-propulsion system

#75

Post by buildbot »

philipkglass wrote: post #27
buildbot wrote: post #21

Earlier quoted context omitted.

Generating matter somehow via E/c^2=m? (I don't think you can do this but I'm not a physicist...)

Known physics permits creating matter from energy: https://en.wikipedia.org/wiki/Pair_production If you have a source of energy on the spacecraft, like a solar panel, you could theoretically convert some of that energy to particle pairs with mass. But this is such an inefficient process (and so inherently low-mass with any practical energy source) that I doubt the claimed thruster could work this way.

100% this would never be practical, more wondering if that technically, it’s possible. Which it seems to be, thanks for the reference!
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