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FastFourierTransform
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How do you think we can get to Proxima b?

15 Nov 2017 08:25

midtskogen wrote:
Source of the post  that technology wasn't made to endure decades in space.  This sounds like hand waving to me.

This is also adressed in part:
Also many of the key technologies this project relies on are currently been tested and surelly there are prototypes for many of them (lase communication, software, nanochips, small cameras, antennas, optical interferometry, solar sails etc...). Very primitive in comparison with what is required here but surelly not science ficcion nor imposible in a few decades. Maybe the bisggest problem is implementing all of them at once in the same... thing.

The circuits coul survive more than 30 years, and other components similarly. The only erosion that has in principle to be taken into account is that of dust and subatomic particles. Thin coatings are been studied for this. Remember that there are currently mission that have been functioning for longer timespans (maybe not so light and maybe not so complicated for sure). I'm much more sceptical, and by far, about SpaceX ambitions than this.

Also there's a very important thing that we are not considering. Many things can go wrong in a space mission. We usually deal with spacecrafts that have to attain huge standards in terms of risk and therefore we don't launch spacecrafts that we think are going to have a 1 in 5 chances of failure (since is a lot of money). But here we have to change our minds a lot. The project aims to make each spacecraft as cheap as an iPhone. They could launch swarms of 1000 nanosails. Even having a probability of 0.1% of success for each spacecraft you can have certain confidence that the mission still is going to be accomplished since probably one is going to reach the destination and transmit back.
 
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How do you think we can get to Proxima b?

15 Nov 2017 10:12

FastFourierTransform wrote:
Many spacecrafts can be lunched (since the costs are going to be insignificant compared to current car-sized spacecrafts) with tiny differences in the angle of ejection as to make some of them arrive much more closer than 1 AU to the planet.

Nice.
I've got to ask: who's eating the probes?
Space is very spacious.
 
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FastFourierTransform
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How do you think we can get to Proxima b?

15 Nov 2017 10:15

Haha sorry.
English is not my main language and this time I wrote quickly so didn't pay attention to this.
 
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Watsisname
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How do you think we can get to Proxima b?

16 Nov 2017 02:41

FastFourierTransform wrote:
Source of the post Watsisname, WOW, amazing explanation as always. I was going to answer that but it's much more helpfull when you give an order of magnitud crunching some numbers.

Thanks, and I enjoyed your thorough post and references as well.

I, like most, was initially extremely skeptical of Project Starshot and pondered the same sorts of questions about the feasibility of it.  But the more I looked into it, the more I found that the obvious objections are solvable, that there don't appear to be any principles of physics that make it impossible or even overly impractical.  I think what really defeated my skepticism was going through a few of the calculations where I expected that something should be an insurmountable problem, but discovered that it isn't.  The calculation for the spin imparted by impact with dust grains was a new one. An interstellar dust grain is tiny, but 0.2c is very fast, so it's hard to get any intuition about the magnitude of the effect without doing the math.  It's satisfying when physics works in your favor, because as Doc and I have joked on Discord, typically the universe hates fun.

To actually do this project would be extremely difficult, and expensive, and there are some (more or less reasonable) assumptions being made regarding the continued miniaturization of key components.  I still don't really expect that this project will actually happen in my lifetime, but I'm cautiously optimistic.  It's by far the least silly idea of it's kind that I've seen, and there are really great minds working on it. :)
 
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How do you think we can get to Proxima b?

05 Jun 2018 06:18

Here is the thing I have been working on... THE PROPULSION DISK! it's a special disk that when struck by even one little atom like hydrogen or helium it boosts forward at incredible speeds! This is how it works, first it sends gamma rays at the mercury disk to ionize it, second it sends a direct current to the mercury nuclei to fling the cations away extremely fast! Finally it adds gamma rays again to ionize it once more, this also tosses the electrons away at incredible speeds, and sense there's not a lot of stuff in space it can move way past the escape velocity of our solar system, which means that it would have increasing acceleration! It also should be with thrusters to keep it in it's direction to, but yeah!
I'm good when it comes to Physics, Algebra, Relativity, Space, and SpaceEngine. But I could still use a LOT of help on the things I still don't know. So I hope I get a lot of help on how all that works, here!
 
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How do you think we can get to Proxima b?

05 Jun 2018 08:12

1) Why Mercury?

2) Why gamma rays?

3) Why a disk?

4) Also, having speed that surpass the escape velocity of the solar system does not mean you are accelerating at all.

5) I didn't understand what you mean with the hydrogen atom that strucks the disk and makes the device boost forward at all. Why?

6) What do you mean by mercury nuclei? The atomic nuclei or some sort of core region inside you disk?

7) You are using onboard fuel, the mercury, since you are making thrust by stripping the electrons from it. This means you are trapped by the rocket equation (you have to carry some mass as fuel and that mass has to be pushed also). The nano-sail proposal is way more efficient in that sense, since the energy to make thrust is not embeded in a fuel that has to be carried with the vehicle but it is gathered here on Earth and beamed using lasers. Why would this idea would work better or just work?

8) Not only you are carrying fuel but also you need a source of energy to create the ionizing current and the ionizing radiation (your gamma rays). Where is that huge amount of energy coming from? Another fuel is providing that or you are using a nuclear reactor somewhere (I can't imagine those amounts of energy been harvested by some solar panels)?

9) If you need a lot of energy and a lot of fuel then each of those would be scarce quite rapidly after some shots. Why is this more efficient than combustion engines in chemical rockets? I mean, in chemical rockets you are releasing energy that was stored in the molecular bonds of a substance but here I don't even see a release in energy, just a large input of energy to extract way less as a result. Right?

10) How many times could you make it to work? I mean, when you have ionized the mercury and eyected the electrons you can't really ionize it again (you just threw the electrons into space). Does you spacecraft works with just one shot?

11) Let's make some assumptions. Let's assume you are able to expel electrons at 99% the speed of light (I don't even understand how you would do that with your device, also considering that ion engines move ions 10.000 times slower than the speed of light). Let's assume the entire spacecraft weights 100 kg (very lightweight considering you want to have at least the mercury-fuel, the gamma ray source and the devide that generates a current). Let's assume the number of electrons in a shot is around 1021 (a water drop contains something like that). If I'm correct then you would gain 1.9 cm/second speed. Not very fast at all. I used the relativistic momentum formula for a rest mass of 1021 electrons moving at 0.99c and calculated the speed of a 100kg mass reacting to that by conservation of linear momentum. 1.9 cm/second is just nothing. If you device can do this process several times maybe it could accumulate but how does your device does it mora than just once? To get to proxima centauri at that speed it would take 67 billion years (more than the entire history of the universe, proxima itself would have moved, the galaxy have rotated and mixed the stellar population that surround us several times, andromeda galaxy collided long time ago, even proxima centauri is dead now as a white dwarf, the galaxy has less stars if its constituents have been held toghether for such a long time).


Sorry if I just missunderstanded what you said, but it looks interesting and I would like to know more and know if you have estimated some numbers for this proposal. Also sorry again for my spell and grammar in english, I'm writing fast right now and can't check.
 
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How do you think we can get to Proxima b?

05 Jun 2018 09:07

Well FastFourierTransform (1) mercury is not the fuel, this it is what the "disk" is made out of, why? because it is a superconductor, gamma rays can pass into it, and it has very fast and overpowered electrons orbiting the nuclei. (2) And by nuclei I mean each atom of the disk, because as you know everything is made out of atoms and what are atoms? nuclei, (which are made of protons and negatrons) with electrons orbiting it. (3) the way it works is the electrons that are flung out by ionization or the cations that are flung out by electrons hit the atoms that float around in the milky way (PS) the gamma rays are not made with radioactive decay, they are made the "Lab way." (4) I'm sure that it would move really fast because every action has an opposite reaction, and electrons grow as they move so they hit atoms with extreme force and extreme mass, this is how space propulsion works, with say... Hydrazine hitting atoms in space, also, the electrons get extra force from being pushed away by cations. Does that help or did I mess up again... Anyway THANK YA'LL!
I'm good when it comes to Physics, Algebra, Relativity, Space, and SpaceEngine. But I could still use a LOT of help on the things I still don't know. So I hope I get a lot of help on how all that works, here!
 
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How do you think we can get to Proxima b?

05 Jun 2018 14:19

It seems I forgot some of your questions FastFourierTransform so I decided that I'm gonna go through your list and answer them, I did answer some of your questions so if I see one I answered already I'll just not show it here. Let's get started.

Why gamma rays? mainly because of the power it produces.
Why a disk? so it can hit a wide field of atoms.
9) If you need a lot of energy and a lot of fuel then each of those would be scarce quite rapidly after some shots. Why is this more efficient than combustion engines in chemical rockets? I mean, in chemical rockets you are releasing energy that was stored in the molecular bonds of a substance but here I don't even see a release in energy, just a large input of energy to extract way less as a result. Right? for one thing, the way it's better than combustion engines is because it can use electricity to make the gamma ray lasers work, and it can, of coarse, use electricity for the capacitors, which can both be powered by a MMRTG or two, which are very light for spacecraft batteries.
10) How many times could you make it to work? I mean, when you have ionized the mercury and eyected the electrons you can't really ionize it again (you just threw the electrons into space). Does you spacecraft works with just one shot? no because the capacitors send a direct current into orbit around the atoms of the disk which get rid of the cations and transform it back into a normal atom so it can boost again.
Sorry if I just missunderstanded what you said, but it looks interesting and I would like to know more and know if you have estimated some numbers for this proposal. Also sorry again for my spell and grammar in english, I'm writing fast right now and can't check. it's okay man, at least you gave some stuff for me to think about!

So there! That's all your questions answered, if you have ANY more then just give the word!
I'm good when it comes to Physics, Algebra, Relativity, Space, and SpaceEngine. But I could still use a LOT of help on the things I still don't know. So I hope I get a lot of help on how all that works, here!
 
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How do you think we can get to Proxima b?

06 Jun 2018 16:34

Charging a capacitor does not magically create new electrons.  It simply re-distributes the electrons that were already there.  As FFT's calculations suggest, you would need a substantial number of additional electrons in order for them to accelerate the disk to any significant velocity.  They would need to comprise a large fraction of the rest mass of the disk, and they would have to be stored at the outset.

If that much of the mass of the disk was made of electrons you would get a spectacular acceleration indeed.  In every direction simultaneously. 

Here is a visual representation of what this electron-fueled omni-directional acceleration would look like.  Scale it up by a few orders of magnitude.

To fix this issue, I would suggest using a propellant with a larger mass to charge ratio (i.e. the positively charged nuclei rather than the electrons).  That is the basis of the ion drive. :)
 
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How do you think we can get to Proxima b?

06 Jun 2018 17:32

Watsisname wrote:
Watsisname:Source of the post Charging a capacitor does not magically create new electrons.  It simply re-distributes the electrons that were already there.  As FFT's calculations suggest, you would need a substantial fraction of the rest mass of the disk to be made of electrons in order for them to accelerate it to any significant velocity. If that much of the mass of the disk was made of electrons you would get a spectacular acceleration indeed.  But in every direction simultaneously.

Um... The electrons come from a battery (MMRTG) and the capacitors turn the volts into direct currents to zap the disk and turn the cations into normal atoms. So, the electrons come from a battery and not out of thin air.
Also, capacitors are made of a two parts a resister, and a dicke switch, along with the metallic poles to conduct the electricity it first uses the resister to get the electrons powered up and then launches them with the dicke switch to create a direct current which is what I wanted.
It seems that not a lot of people get what I mean of how this works, what it's made of, or the speed it makes so I'm gonna say everything again in great detail.
The propulsion disk is a disk that is made up of mercury (the material) so it can conduct electricity, why? well I'll get there in a moment, anyway, the acceleration process starts with gamma ray lasers (or beta ray lasers) that hit the disk, therefore ionizing it, these ions are called cations which means that they strip electrons off of atoms, it needs to do this so it can add electrons back into it and repel the cations, as the cations fly they push on an atom which propels it forward, this also happens when the cations are added, the electrons are repelled and push on atoms to propel the spacecraft. Ever heard of nanoFET?
https://en.wikipedia.org/wiki/Nano-particle_field_extraction_thruster
I'm good when it comes to Physics, Algebra, Relativity, Space, and SpaceEngine. But I could still use a LOT of help on the things I still don't know. So I hope I get a lot of help on how all that works, here!
 
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How do you think we can get to Proxima b?

07 Jun 2018 00:18

Electrons and cations attract, not repel.

Batteries and MMRTGs also do not make new electrons anymore than capacitors do.  They are not little tanks that spit out electrons whenever current is drawn.  What they do is move the charge carriers that were already present in the circuit by generating an electromotive force.  So you haven't clarified for me how you would be storing the necessary amount of charge to produce meaningful thrust from electrons, let alone how you would store it without producing a spectacular Coulomb explosion.


Let's try turning this idea more quantitative.

1)  What is the work function for the mercury that the disk is constructed from?
2)  What is the gramma ray photon energy you propose hitting it with?
3)  Calculate the kinetic energy of an electron ejected from the material by a gamma ray strike.  Comment on how you plan for these ejected electrons to be captured and utilized.
 
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How do you think we can get to Proxima b?

07 Jun 2018 04:40

Doesn't clarify this to me either. And I'm gratefull that I'm not so confused about the actual physics here as I read Watsisname's responses.

In fact there are important points still to be adressed. I suspect the amount of energy you need for the gamma ray laser is way beyond any other energetic output in this system. Still,  why mercury? why not xenon? Where are the new electrons really coming from?

Propulsion Disk wrote:
Source of the post these ions are called cations which means that they strip electrons off of atoms, it needs to do this so it can add electrons back into it and repel the cations, as the cations fly they push on an atom which propels it forward

This part is confusing to me. If I understanded correctly this is a many-steps process: (1) Input energy to separate negative charge from positive (electrons and nucleai), in your case ionizing mercury atoms. (2) Then you need more input energy to make the electrons turn back and collide with the nucleai (in reality you don't need energy they would tend to return since they atract, that's exactly the reason you needed energy in the first place to separate them... anyway), but why? why separating and joining them which is, as far as I see, reversing the process to return to the initial conditions would give the cations more kinetic energy than the electrons? 3) You want the electrons to kick the cations away to gain thrust? wouldn't the electrons repel in the opposite direction with the same force? Assuming again that both would repel (which is absurd) you seem to want to break Newton's third law in this step. Or maybe you want to push the cations by pushing the electrons with the gamma ray laser (a second use of it)? In that way they would be pushed indeed in one direction, but then why pushing the electrons to make them push the cations? why don't use the gamma ray to directly push the cations without the electrons intervening? And why you even need the first and second step? why you need to separate charges and then make them collide?

I see a lot of steps here, and remember that in each process you transform energy from one object to other and in one form to another so you are inevitably losing a lot of energy by dissipation (imposible to overcome in the end because of the second law of thermodynamics).

Even if electrons and cations attracted each other (which doesn't happen at all) I see this billiard as an ineficient complex path to dissipate more and more energy while you seem to see not only a perfectly efficient path but even a chain that is able to aplify the amount of energy in some magical way by distracting the attention of the inquirer of how conservation laws work by increasing the complexity of the chain of interactions you seem to need until non-physics leak into the explanation silently and we get deceived.

So, as far as your explanation goes I can only see violations of either Newton's 3rd Law, the 2nd Law of Thermodynamics, Coulomb's Law, or a combination of those. Nature is a hard coded restrictor some times.
___________________________________

By the way I see that both Watsisname and me have talked about Ion engines (like the one used by the Dawn spacecraft). This is because the closest to your invention plausible idea that one can think of is exactly that, an ion engine. It works by accelerating ions with an electric field (no by an energy-expensive gamma ray pushing-electron-pushing-cation laser). Is a clever idea. And it is currently been used in space. But is has some (many) dissadvantages and dosen't fit to interstellar probe needs.

An ion engine can't propel to large speeds (remember, you want to reach proxima centauri, which is far away) and above all it can't give you large accelerations (remember you want to gain huge speeds in a reasonable time to get there in a reasonable time). An ion thruster needs two days of continuous acceleration to gain 0.025 km/sec (a car driving through a highway). You would need 9 years to gain sufficient speed as to escape the Solar System gravitational influence. 10 years just to gain that speed! but you would need a lot more time to actually physically get out of the Solar System since at that speed you would still need 16 years to reach the Voyagers (that's in principle interesting since the Voyagers have taken 40 years to reach that distance while our immaginary ion spacecraft needs 25 years). Been able to get to the escape velocity of the Solar System from Earth means a staggering 42 km/s speed, but with that speed you would still need 30.000 years to reach Proxima Centauri!! The advantage of these thrusters is that you can accelerate constantly even if the acceleration is puny. But it needs fuel (the matter were the ions come from), which is a Xenon gas in in the case of Dawn (not mercury as in your scenario). The need of fuel means that the accelleration is not eternal, it would finish when the Xenon has been depleted (or when your mercury atoms have been fully ionized and ejected). How can one extend the life of the engine? By adding more fuel. But adding more fuel implies more mass for the spacecraft and that means that the same amount of thrust is going to generate less accelleration (inertia is not our friend here), so there's an equilibrium point between the amount of time you want the engines to operate and the amount of acceleration you could possibly have, all controled by the kind of gas you are using and the total amount of it. So this technology has its limits. Also to generate the electric field to expell the ions you need an energy source (in the case of Dawn it was provided by solar panels), analogous to your gamma ray laser using some energy coming from "no one knows yet" to first ionize your mercury disk. If you plan an ion engine to go outside of the solar system first consider if there is sufficient time for it to reach those speeds with that amount of acceleration, second consider if there's sufficient fuel to have that acceleration and third consider if there is too much fuel to been able to push the spacecraft to that speed with your energy limitations. In this case you would need some nuclear battery onboard to power the electric field (Dawn is close to the sun so the solar panels are able to collect some energy but farther from Jupiter this is currently impossible, as you can see by the fact thet Cassini, Voyager, New Horizons etc... are all solar-panel-less spacecrafts). So you would need a nuclear reactor as the one used by the Voyagers to make your extremely slow ion drive work. So assuming that the Xenon is infinite and lightweight you still need to acount for the nuclear fuel to make your engine work. That secondary fuel can endure maybe 50 years? Making your spacecraft reach maybe 100 km/s at the final moment when the engine stops? At that speed you would still need 12.600 years to reach Proxima Centauri. And that is why no ion thrusters have been proposed for missions like that (yours is a special ion thruster that violates physics).

That's why ion engines are not designed for missions that require huge speeds to arrive to far away destinations but rather for nearby missions that requiere progressive changes in orbital parameters. As I said before getting to Proxima Centauri is a very difficult task. No ion drive and no chemical rocket could reach it in our lifetimes or even our civilization lifespan. We need a breakthrough in our understanding of propulsion, and that's where the idea of a Solar sail pushed by lasers comes. You see, chemical rockets, ion engines, even fantastic disk propulsion futuristic device that shots ions from a mercury disk and electrons from a battery, all of those are just the same schema. All of those need onboard fuel to propel and even onboard fuel to make the engine start using the fuel to propel. That's energy stored in matter, and matter has mass, mass that has to push itself (and the entire spacecraft). But what if we made a spacecraft propeled by energy that is not embeded in a fuel onboard the spacecraft? That's the idea behind solar sails; we consume a lot of energy here on earth (nuclear energy is the proposal) to power a laser that shots to a sheet of reflective material in space, no need for fuel, engines or batteries onboard the spacecraft, all of that can be placed and controled here on Earth where we have plenty of material while the spacecraft only need to have the instruments onboard (and a little battery to power them), that means little mass been pushed from home and not by itself. Also the idea is to make instrumets very lightweight (something that you can't do with some fuel because it would mean you are cutting it's mass and it's energy output) as to arrive to the 1 gramm limit for the entire spacecraft. That is trully efficient. The escape velocity of the Solar System from Earth's distance is 0.014% the speed of light, the expected velocity for a sail like this is 20% the speed of light. That is the first realistic proposal to travel to the closest star.

Your device, even if it worked, would never be even close to that, just by the limitations of the rocket equation, by which your disk propulsion is limited and the solar sail is not.
 
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How do you think we can get to Proxima b?

07 Jun 2018 06:24

Watsisname wrote:
Source of the post Electrons and cations attract, not repel.Batteries and MMRTGs also do not make new electrons anymore than capacitors do.  They are not little tanks that spit out electrons whenever current is drawn.  What they do is move the charge carriers that were already present in the circuit by generating an electromotive force.  So you haven't clarified for me how you would be storing the necessary amount of charge to produce meaningful thrust from electrons, let alone how you would store it without producing a spectacular Coulomb explosion.Let's try turning this idea more quantitative.1)  What is the work function for the mercury that the disk is constructed from?2)  What is the gramma ray photon energy you propose hitting it with?3)  Calculate the kinetic energy of an electron ejected from the material by a gamma ray strike.  Comment on how you plan for these ejected electrons to be captured and utilized.
FastFourierTransform wrote:
Source of the post Doesn't clarify this to me either. And I'm gratefull that I'm not so confused about the actual physics here as I read Watsisname's responses.In fact there are important points still to be adressed. I suspect the amount of energy you need for the gamma ray laser is way beyond any other energetic output in this system. Still,  why mercury? why not xenon? Where are the new electrons really coming from?Propulsion Disk wrote:Source of the post these ions are called cations which means that they strip electrons off of atoms, it needs to do this so it can add electrons back into it and repel the cations, as the cations fly they push on an atom which propels it forwardThis part is confusing to me. If I understanded correctly this is a many-steps process: (1) Input energy to separate negative charge from positive (electrons and nucleai), in your case ionizing mercury atoms. (2) Then you need more input energy to make the electrons turn back and collide with the nucleai (in reality you don't need energy they would tend to return since they atract, that's exactly the reason you needed energy in the first place to separate them... anyway), but why? why separating and joining them which is, as far as I see, reversing the process to return to the initial conditions would give the cations more kinetic energy than the electrons? 3) You want the electrons to kick the cations away to gain thrust? wouldn't the electrons repel in the opposite direction with the same force? Assuming again that both would repel (which is absurd) you seem to want to break Newton's third law in this step. Or maybe you want to push the cations by pushing the electrons with the gamma ray laser (a second use of it)? In that way they would be pushed indeed in one direction, but then why pushing the electrons to make them push the cations? why don't use the gamma ray to directly push the cations without the electrons intervening? And why you even need the first and second step? why you need to separate charges and then make them collide? I see a lot of steps here, and remember that in each process you transform energy from one object to other and in one form to another so you are inevitably losing a lot of energy by dissipation (imposible to overcome in the end because of the second law of thermodynamics).Even if electrons and cations attracted each other (which doesn't happen at all) I see this billiard as an ineficient complex path to dissipate more and more energy while you seem to see not only a perfectly efficient path but even a chain that is able to aplify the amount of energy in some magical way by distracting the attention of the inquirer of how conservation laws work by increasing the complexity of the chain of interactions you seem to need until non-physics leak into the explanation silently and we get deceived.So, as far as your explanation goes I can only see violations of either Newton's 3rd Law, the 2nd Law of Thermodynamics, Coulomb's Law, or a combination of those. Nature is a hard coded restrictor some times.___________________________________By the way I see that both Watsisname and me have talked about Ion engines (like the one used by the Dawn spacecraft). This is because the closest to your invention plausible idea that one can think of is exactly that, an ion engine. It works by accelerating ions with an electric field (no by an energy-expensive gamma ray pushing-electron-pushing-cation laser). Is a clever idea. And it is currently been used in space. But is has some (many) dissadvantages and dosen't fit to interstellar probe needs.An ion engine can't propel to large speeds (remember, you want to reach proxima centauri, which is far away) and above all it can't give you large accelerations (remember you want to gain huge speeds in a reasonable time to get there in a reasonable time). An ion thruster needs two days of continuous acceleration to gain 0.025 km/sec (a car driving through a highway). You would need 9 years to gain sufficient speed as to escape the Solar System gravitational influence. 10 years just to gain that speed! but you would need a lot more time to actually physically get out of the Solar System since at that speed you would still need 16 years to reach the Voyagers (that's in principle interesting since the Voyagers have taken 40 years to reach that distance while our immaginary ion spacecraft needs 25 years). Been able to get to the escape velocity of the Solar System from Earth means a staggering 42 km/s speed, but with that speed you would still need 30.000 years to reach Proxima Centauri!! The advantage of these thrusters is that you can accelerate constantly even if the acceleration is puny. But it needs fuel (the matter were the ions come from), which is a Xenon gas in in the case of Dawn (not mercury as in your scenario). The need of fuel means that the accelleration is not eternal, it would finish when the Xenon has been depleted (or when your mercury atoms have been fully ionized and ejected). How can one extend the life of the engine? By adding more fuel. But adding more fuel implies more mass for the spacecraft and that means that the same amount of thrust is going to generate less accelleration (inertia is not our friend here), so there's an equilibrium point between the amount of time you want the engines to operate and the amount of acceleration you could possibly have, all controled by the kind of gas you are using and the total amount of it. So this technology has its limits. Also to generate the electric field to expell the ions you need an energy source (in the case of Dawn it was provided by solar panels), analogous to your gamma ray laser using some energy coming from "no one knows yet" to first ionize your mercury disk. If you plan an ion engine to go outside of the solar system first consider if there is sufficient time for it to reach those speeds with that amount of acceleration, second consider if there's sufficient fuel to have that acceleration and third consider if there is too much fuel to been able to push the spacecraft to that speed with your energy limitations. In this case you would need some nuclear battery onboard to power the electric field (Dawn is close to the sun so the solar panels are able to collect some energy but farther from Jupiter this is currently impossible, as you can see by the fact thet Cassini, Voyager, New Horizons etc... are all solar-panel-less spacecrafts). So you would need a nuclear reactor as the one used by the Voyagers to make your extremely slow ion drive work. So assuming that the Xenon is infinite and lightweight you still need to acount for the nuclear fuel to make your engine work. That secondary fuel can endure maybe 50 years? Making your spacecraft reach maybe 100 km/s at the final moment when the engine stops? At that speed you would still need 12.600 years to reach Proxima Centauri. And that is why no ion thrusters have been proposed for missions like that (yours is a special ion thruster that violates physics).That's why ion engines are not designed for missions that require huge speeds to arrive to far away destinations but rather for nearby missions that requiere progressive changes in orbital parameters. As I said before getting to Proxima Centauri is a very difficult task. No ion drive and no chemical rocket could reach it in our lifetimes or even our civilization lifespan. We need a breakthrough in our understanding of propulsion, and that's where the idea of a Solar sail pushed by lasers comes. You see, chemical rockets, ion engines, even fantastic disk propulsion futuristic device that shots ions from a mercury disk and electrons from a battery, all of those are just the same schema. All of those need onboard fuel to propel and even onboard fuel to make the engine start using the fuel to propel. That's energy stored in matter, and matter has mass, mass that has to push itself (and the entire spacecraft). But what if we made a spacecraft propeled by energy that is not embeded in a fuel onboard the spacecraft? That's the idea behind solar sails; we consume a lot of energy here on earth (nuclear energy is the proposal) to power a laser that shots to a sheet of reflective material in space, no need for fuel, engines or batteries onboard the spacecraft, all of that can be placed and controled here on Earth where we have plenty of material while the spacecraft only need to have the instruments onboard (and a little battery to power them), that means little mass been pushed from home and not by itself. Also the idea is to make instrumets very lightweight (something that you can't do with some fuel because it would mean you are cutting it's mass and it's energy output) as to arrive to the 1 gramm limit for the entire spacecraft. That is trully efficient. The escape velocity of the Solar System from Earth's distance is 0.014% the speed of light, the expected velocity for a sail like this is 20% the speed of light. That is the first realistic proposal to travel to the closest star.Your device, even if it worked, would never be even close to that, just by the limitations of the rocket equation, by which your disk propulsion is limited and the solar sail is not.


Yeah. I mainly was wanting a propulsion system that doesn't have fuel restrictions...
I'll keep working on it and taking your info into account!
I'm good when it comes to Physics, Algebra, Relativity, Space, and SpaceEngine. But I could still use a LOT of help on the things I still don't know. So I hope I get a lot of help on how all that works, here!
 
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How do you think we can get to Proxima b?

07 Jun 2018 08:15

Propulsion Disk wrote:
Source of the post Yeah. I mainly was wanting a propulsion system that doesn't have fuel restrictions...
I'll keep working on it and taking your info into account!

Awesome!! Keep the ideas coming. Good way of handling our skepticism :)
 
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How do you think we can get to Proxima b?

07 Jun 2018 09:24

FastFourierTransform wrote:
Source of the post So, as far as your explanation goes I can only see violations of either Newton's 3rd Law, the 2nd Law of Thermodynamics, Coulomb's Law, or a combination of those. Nature is a hard coded restrictor some times.

Yeah. project starshot's thrusters are "photon thrusters" which also violate those laws, because light doesn't have any mass so newton's laws just got broken. It sort of works with the second law of thermodynamics. and of coarse doesn't have anything to do with coulomb's law. so how does it move? I know that it's because light has inertia, but that still shouldn't do anything because light still doesn't have any mass. so how does it push?
I'm good when it comes to Physics, Algebra, Relativity, Space, and SpaceEngine. But I could still use a LOT of help on the things I still don't know. So I hope I get a lot of help on how all that works, here!

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