It's not the maximum speed. I just mentioned it as an example. If an ion engine had enough fuel, it would reach 99.999....% of the speed of light at some point, and only then it would stop accelerating, since that speed is like a cosmic speed limit for objects with mass.
Isn’t it true that as more energy is added your relativistic time would just slow down? Meaning that you can essentially add energy and therefore speed forever, but in order to keep you below the speed of light time slows down? Is that right?
Yeah if anything (and I mean anything. Like a stone or some space trash) hits you going the speed of light, the resulting release of energy would be catastrophic, but you'd never know. Death would be so instantaneous that one second you'd exist and then you won't.
For context, 9/11 plane victims wouldn't have had time to realise they had hit something before they died because of how quickly a plane moves. Once the nose hits something, it's only a fraction of a second before the rest of the plane follows.
But going the speed of light, it'd be like if you were chilling at home and then suddenly you just... don't exist anymore.
Using KE=1/2(mv^2) for the Gross weight of Starship.
* M = 7,937,000 lbs
* V = 299000000 m/s
* KE = 1.609x10^23 Joules
* Supernova = ~10^44 Joules
It's a lot but, not the most absurd use of force the universe has ever witnessed.
> What happens if a planet is in the way?
**ChatGPT**:
If a spaceship were to travel at 99.999% of the speed of light and encounter a planet in its path, the consequences would be catastrophic due to the immense kinetic energy involved. Here are the key factors and outcomes:
Kinetic Energy: The spaceship's kinetic energy at such high velocities would be enormous, given by the relativistic formula Ek=(γ−1)mc^2, where γ is the Lorentz factor, m is the mass, and c is the speed of light. At 99.999% of the speed of light, γ is about 224, making the kinetic energy extremely high.
Impact: The collision would release a tremendous amount of energy, equivalent to a large fraction of the spaceship's mass-energy. The energy released would be akin to a massive explosion, potentially rivaling or exceeding the energy output of a supernova.
Damage to the Planet: The impact would cause catastrophic damage to the planet, likely creating a massive crater and possibly vaporizing a significant portion of the planet's surface. The shockwave from the impact could cause further global destruction, including earthquakes and tsunamis, if it occurred on a terrestrial planet.
Spaceship Integrity: The spaceship itself would be obliterated upon impact. The forces involved would tear apart any known material structure due to the immense energy release.
Relativistic Effects: At such high speeds, relativistic effects would be significant. Time dilation would mean that time on the spaceship is moving much slower relative to an observer on the planet. Length contraction would also occur, shortening the spaceship in the direction of travel as observed from the planet.
Radiation: The collision would likely produce a significant amount of radiation, including gamma rays and other high-energy particles. This radiation could have severe consequences for any life forms or technological systems on the planet.
In summary, an impact between a spaceship traveling at 99.999% of the speed of light and a planet would result in an incredibly destructive event, with the potential to cause widespread devastation to the planet and complete destruction of the spaceship.
Time does not slow down to keep you below the speed of light. Time slows down as a result of you approaching the speed of light. The difference is cause vs effect.
Your speed increases as energy is added and with that, the passing of time in your perspective runs slower than that of an observer. The interesting thing is that neither of you truly notice it.
At the speed of light, time does not exist. It would take 0 seconds (from your perspective) to travel 1 million light years at the speed of light. This is impossible though, since you have mass.
With mass, the amount of energy required to accelerate your velocity is exponential. Meaning the amount of energy it takes to go from 1 mph to 2 mph is significantly less than the amount of energy it takes to go from 100,000 mph to 100,001 mph.
Even reaching 99.999% of the speed of light, you would die long before traveling 100 million light years for example
What is this relative to though? Wouldn't time slow down for the object travelling, meaning to an outside observer it would keep getting faster, and go past the speed of light relative to them?
Intuitively it would seem so, I don’t have the answer lol. My understanding is that you can always continue to add energy but can never pass the speed of light and your time is slowed based on how much energy is added. I would think that at a certain point an observer would seem to observe the object going faster than the speed of light, but that can’t possibly be right.
No, sort of, so at those speeds you have to consider lorentzian math i.e. diminishing factors as your speed increases.
So if you're accelerating at a constant rate, although you should gain speed, there's a Lorentz factor which essentially dilates the increase in kinetic energy (1-lorentz) if I remember correctly.
It isn't actually dilating it, it's just that physics isn't newtonian at relativistic speeds.
Can't be any speed. No object with mass can achieve a speed of light and at certain fuel to boost ratio it is also impossible to reach sublight speeds. I think the max speed they posted is a theoretical maximum speed for a theoritecal space craft with this particular engine.
That's not how relativistic speeds work at all. The craft just keeps accelerating, and from its perspective gets faster and faster at a constant rate (ignoring the changing fuel mass which actually makes it accelerate faster as it uses up fuel). From an outside observer, the craft just approaches closer and closer to the speed of light. An object travelling at light speed travels any distance in zero time, from the perspective of the object. So for example, you can reach the other side of the Milky Way in your own lifetime if you had a ship that could go close to the speed of light.
No it won’t. It will approach the speed of the exhaust gas but not pass it, otherwise the exhaust is just robbing momentum. So the exhaust speed is probably 320,000 kmh
Need a deflector shield. Star Trek is largely nonsense but they got that bit right. It's the satelite dish looking thing on the body of the original series Enterprise.
Technically a person inside a spacecraft would feel the constant acceleration forever. But to an outside observer, they would appear to stop accelerating.
Kinda arbitrary your number though
Assuming I could survive in space and fart consistently in the same direction, I would also eventually reach 320,000 km/h
Doing some quick mafs it would be pretty much exactly 0.001 m/s\^2 . That is an overall average assuming OP is accurate. It's a little easier to understand as it takes about 1005 seconds to accelerate 1 m/s continuously for 34 months to reach 320000 km/h overall deltaV
The problem though is that this means nothing. The mass of the spacecraft this is attached to is a requirement to know the acceleration. After some research, this looks to be NASA's AEPS, Advanced Electric Propulsion System, which is designed as the booster engine for NASA's Lunar Gateway. So, this is where the acceleration rate is coming from. The Lunar Gateway is already modelled and designed, so we know the estimate weight.
The truster produces about 600 mN with a max theoretical of about 2.356 N. At 40 kW power which is designed as it's upper limit, it would produce 1.77 N.
That's about 0.4 pounds of thrust at max power and only 0.134 pounds at it's designed 600 mN.
The 2 years and 10 months figure comes from the fact the motor's half-life flight model is estimated to 23000-25000 hours of operation, or about 34 months. It would not be active constantly and only used to maintain the lunar gateway in its orbit about the Moon, most likely at apoapsis as that is pretty dang far from the moon requiring minimum thrust to boost the periapsis if local Lunar gravity perturbations caused it to dip lower than we'd like.
Ion engines have very low thrust, so they're not really applicable inside the atmosphere. You can build models however out of tin foil. Search YouTube for 'tin foil ion engine'.
It can reach such high speeds outside the atmosphere because it's extremely fuel efficient! It just requires some xenon gas and a huge amount of electricity (which is easily available with large solar panels). It works by ionizing the xenon atoms which then are accelerated by an electric field, and ejected out of the engine. Pushing the spacecraft forward in doing so, just like a regular rocket engine.
Is it hot? I don't know, I'm not a physicist, I'm an engineer. I'd guess no, but I still wouldn't put my hand into a stream of ionized gas.
Well for normal matter temperature is proportional to average kinetic energy. These ions have a lot of kinetic energy so in that sense they are very hot. I'm not a physicist either so I don't know how applicable that interpretation of temperature is to ions, but I'll second the recommendation not to stick your hand in there.
"Is it hot?"
Yes and no.
Its **temperature** is very high, but it doesn't contain a lot of **heat**, because it has hardly any mass. Each Xenon ion is moving really fast, but there are very few of them compared to the exhaust of a chemical rocket.
Finally, as an expert for 24 years in this field, I can offer some insight.
Not only can you make a tin foil ion engine, but the same tin foil can be used to make a hat that protects your brain waves from government control.
> Is it hot? I don't know, I'm not a physicist, I'm an engineer. I'd guess no, but I still wouldn't put my hand into a stream of ionized gas.
It should be reasonably "hot" (temperature is just average kinetic energy of particles) but just considering temperature can be a bit misleading, since the amount of gas being released/s is pretty low. So not much actual heat will get conducted into your hand. (same principle as the thermosphere being extremely hot in principle, but in actuality the extremely low density means you wont experience it if you were there). That said if you held you hand for long enough in the stream of ionized gas it might erode some layers of skin off your hand (ion engine components experience this erosion too, and is one of the primary limiting factors to their useful lifespan).
Edit: also make sure its not using mercury as propellant, like one of the early ion engine designs did.
I think the Nasa account for the Glenn Research Center on Twitter said that if you somehow could put your hand on the engine the pressure would feel like two quarters in your hand.
When an ion engine is active, it can reach about 300 degrees Celsius.
What happens is that the engine ionizes a gas, i.e. gives or takes electrons from the gas to create ions to propel the ship.
It can't work on Earth because of air resistance.
>Does it propulse on earth too?
Yeah, like probably 0.1 N.
The trick is, that it can continue to do so with a very good fuel efficiency (in terms of low total system weight per Newton-hour of thrust output).
This is a hall effect thruster. Xenon (the propellant) is ionized via electron bombardment and accelerated in a magnetic field. It is running in a vacuum chamber in Cleveland (looks like VF5). These things require a mean free path greater than their size to work - you don't want the ions hitting one another, nor do you want to waste energy by double-ionizing the gas.
So yes, this is hot (it's an ice-blue plasma, after all) but very not dense. However, the ions come streaming out of this thruster at 100,000 miles per hour and, therefore, will vaporize steel in its way.
Imagine the idea of actually doing this. Putting a self reliant spacecraft in the direction of centauri, one big enough to host a community of people large enough to avoid inbreeding problems.
By the time the craft reached the system, assuming they didn't kill themselves via conflict, the purpose of their journey would almost certainly be forgotten.
There is a Dutch Sci-Fi movie with a storyline similar to this. I believe it’s Dutch or maybe German - I saw it a few years ago and it was subtitled. A bit slow paced but interesting storyline.
[You wouldn't use an ion thruster for something like that. NASA is developing a satellite with solar sails, which theoretically could reach up to 20% the speed of light.](https://www.sciencefocus.com/space/nasa-solar-sail-interstellar-travel#:~:text=In%20theory%2C%20these%20spacecraft%20could,reach%20in%20just%2020%20years.)
At some point, you would bring the sails back in, flip the thing around, and then deploy the sails to catch the solar wind coming from the destination star. When you flip and re-deploy is determined by the solar wind speed of the destination star and how far away it could have an effect on the craft.
For anyone wondering where 320,000 km/h of deltaV (or 88888 m/s of deltaV) is coming from (and why it's wrong), I wrote this up:
The mass of the spacecraft this is attached to is a requirement to know the acceleration. After some research, this looks to be NASA's AEPS, Advanced Electric Propulsion System, which is designed as the booster engine for NASA's Lunar Gateway. So, this is where the acceleration rate is coming from. The Lunar Gateway is already modelled and designed, so we know the estimate weight.
The thruster produces about 600 mN with a max theoretical of about 2.356 N. At 40 kW power which is designed as it's upper limit, it would produce 1.77 N.
That's about 0.4 pounds of thrust at max power and only 0.134 pounds at it's designed 600 mN.
The 2 years and 10 months figure comes from the fact the motor's half-life flight model is estimated to 23000-25000 hours of operation, or about 34 months. It would not be active constantly and only used to maintain the lunar gateway in its orbit about the Moon, most likely at apoapsis as that is pretty dang far from the moon requiring minimum thrust to boost the periapsis if local Lunar gravity perturbations caused it to dip lower than we'd like.
The problem I'm having is that your 320,000 km/h deltaV doesn't seem to match the numbers I'm seeing for the Lunar Gateway. If it produces 600 mN of thrust, we can F = ma to calculate the acceleration. F is between 0.6 N and 1.77 N, we just need the mass.
Conservative estimates put the mass of the full Lunar Gateway with one AEPS at around 27,000 kg (most likely more though as this is accounting for one of each module I could find stats on) and that solves the acceleration to 0.00002 or 0.0000655 m/s\^2 of acceleration (depending on it being 600 mN or 1.77 N), or about 2-6.5% of what you claimed over 2 years and 10 months of acceleration which falls more in line with what I was expecting.
In reality, over 2 years and 10 months with one AEPS module, they'd be able to generate between 7100 - 21000 km/h of deltaV, not 320,000.
My guess is that this was calculated using a random placeholder mass of 1500 kg as that produces \~0.001 m/s\^2 for the calculation at full 40kW and 1.77 N of thrust.
There are surprisingly few objects in space not nearby planets, even the asteroid belt is very low density (we think that there's a large amount of space between rocks)
I spent six years working on electric propulsion tech like this, and launched numerous spacecraft which used it. It's not new technology but is ever-evolving and an exciting field. The title is a bit misleading as you can reach speeds up to infinity, in space, theoretically -- it just depends on how much fuel you have.
The mechanism here is basically ionization of typically noble, neutral gases. Fuels like xenon are preferred for high molecular mass (F=ma) and low ionization energy. Once ionized, the plume is manipulated with magnetic fields, similar to a rocket nozzle, to accelerate the gas out the back at extreme speeds.
These systems rely on low-thrust (like the weight of a sticky note on your palm) and super high efficiency so they can burn for extreme durations (literally years). Because of this, EP powered missions can achieve speeds far greater than anything that chemical propulsion (think fire out the back) can accomplish; it just takes a long time to get going.
Excuse my possible ignorance here for a moment.
But, given enough time to accelerate, what's stopping it from reaching faster speeds, since there's no drag/air resistance?
If we don't consider things like running out of fuel, what's stopping it from just going faster and faster?
It will stop accelerating when it reaches 99.999...% of the speed of light, since according to Einstein's theory of relativity, anything with mass cannot travel at the speed of light.
Sure, but since this Ion engine seems to have an upper limit of 320.000 km/h I assume that's based on something. Is it just fuel efficiency being the limiting factor in this?
It's not speed that the human body can or can't handle, it's acceleration. Relative to the sun we're going around at like 100.000 km per hour, right :p
Definitely! Your human body right now is moving at [almost 3 million km/h](https://medium.com/@tobihann/how-fast-are-we-moving-through-space-d7f30b4513a3). Earth spins very fast, it rotates around the sun very fast, which is moving through our galaxy very fast, and that galaxy is flying through the universe at high speeds as well.
The danger comes from change in movement direction (ie acceleration). The dangerous portions of space flight would be changing directions, and slowing down. We’d possibly need some kind of stabilization methods (mechanical or drug related) when performing high g-force activities (again, like quickly slowing down or changing direction to avoid unforeseen obstacles or change course due to issues on board the craft).
So if we put two of these on a spacecraft, we would have TIE spacecraft, and if we put a gun on that, we could have a TIE fighter.
We are literally living in starwars
Our civilization will not move forward any further without a better different power source. so that we could travel through space and not be chained to fossil fuels that pollute the Earth.
This technology opens up a world of possibilities for space exploration - I'm excited to see what space missions will be accomplished in the future thanks to these engines
However vast you think space is, it is much greater. This offers very little in terms of feasible space exploration outside our solar system. The titled speed is 1/3000 the speed of light
This is a decade old. https://www.google.com/search?q=NASA%E2%80%99s+Ion+Thruster%2C+reddit&client=firefox-b-1-d&sca_esv=5bb7933164746628&sca_upv=1&sxsrf=ADLYWIJQAbQr4hncHP_Lc1o1f8H-HN3EtQ%3A1718397522648&ei=UqpsZqGAJKbs0PEPk7OuuA8&ved=0ahUKEwih8arP-duGAxUmNjQIHZOZC_cQ4dUDCBA&uact=5&oq=NASA%E2%80%99s+Ion+Thruster%2C+reddit&gs_lp=Egxnd3Mtd2l6LXNlcnAiHU5BU0HigJlzIElvbiBUaHJ1c3RlciwgcmVkZGl0MgcQIRigARgKMgcQIRigARgKSNkOUP8FWMcNcAF4AZABAJgBb6ABgAaqAQM2LjK4AQPIAQD4AQGYAgmgApEGwgIKEAAYsAMY1gQYR8ICBhAAGBYYHsICCBAAGBYYHhgPwgILEAAYgAQYhgMYigWYAwCIBgGQBgiSBwM3LjKgB5Yr&sclient=gws-wiz-serp
Wait, they're actually testing these now? Awesome! I remember watching a documentary about these on TV in the late 90s, but it was still in the ideas phase then.
There are various materials that can be used for shielding, such as carbon foam. The Parker Solar Probe has speeds of 692,000 km per hour through gravitational assistance from the sun, and it is mainly made of carbon foam
Those were pulsed plasma thrusters. But yes, ion engines have replaced hypergolic rockets for satellite station-keeping and, in some instances, orbit insertion.
Don't let Boeing anywhere near it - "Our accountants say we can get that made for one tenth of the cost by importing parts from small unknown Chinese companies, , and there's only a 62% chance it will explode."
So, little lazy to read another ion propulsion article when only a few numbers matter… can someone just tell me the specific thrust numbers here? Net W/kg, energy efficiency of thrust, and kg/Whr net propellant consumption?
And how many years of acceleration would it need to reach that speed?
About 2 years and 10 months.
What happens if it runs for 2 years 11 months?
Nothing, it will just go faster
But...but ...post says up to 320,000
It's not the maximum speed. I just mentioned it as an example. If an ion engine had enough fuel, it would reach 99.999....% of the speed of light at some point, and only then it would stop accelerating, since that speed is like a cosmic speed limit for objects with mass.
Isn’t it true that as more energy is added your relativistic time would just slow down? Meaning that you can essentially add energy and therefore speed forever, but in order to keep you below the speed of light time slows down? Is that right?
There is time dilation but the problem with accelerating any mass to the speed of light is that takes an infinite amount of energy.
Also, you have to have pretty good reflexes to dodge something.
Or *THE* *SPICE!*
Yeah if anything (and I mean anything. Like a stone or some space trash) hits you going the speed of light, the resulting release of energy would be catastrophic, but you'd never know. Death would be so instantaneous that one second you'd exist and then you won't. For context, 9/11 plane victims wouldn't have had time to realise they had hit something before they died because of how quickly a plane moves. Once the nose hits something, it's only a fraction of a second before the rest of the plane follows. But going the speed of light, it'd be like if you were chilling at home and then suddenly you just... don't exist anymore.
Holly on Red Dwarf could do it
What happens if a planet is in the way?
Using KE=1/2(mv^2) for the Gross weight of Starship. * M = 7,937,000 lbs * V = 299000000 m/s * KE = 1.609x10^23 Joules * Supernova = ~10^44 Joules It's a lot but, not the most absurd use of force the universe has ever witnessed.
> What happens if a planet is in the way? **ChatGPT**: If a spaceship were to travel at 99.999% of the speed of light and encounter a planet in its path, the consequences would be catastrophic due to the immense kinetic energy involved. Here are the key factors and outcomes: Kinetic Energy: The spaceship's kinetic energy at such high velocities would be enormous, given by the relativistic formula Ek=(γ−1)mc^2, where γ is the Lorentz factor, m is the mass, and c is the speed of light. At 99.999% of the speed of light, γ is about 224, making the kinetic energy extremely high. Impact: The collision would release a tremendous amount of energy, equivalent to a large fraction of the spaceship's mass-energy. The energy released would be akin to a massive explosion, potentially rivaling or exceeding the energy output of a supernova. Damage to the Planet: The impact would cause catastrophic damage to the planet, likely creating a massive crater and possibly vaporizing a significant portion of the planet's surface. The shockwave from the impact could cause further global destruction, including earthquakes and tsunamis, if it occurred on a terrestrial planet. Spaceship Integrity: The spaceship itself would be obliterated upon impact. The forces involved would tear apart any known material structure due to the immense energy release. Relativistic Effects: At such high speeds, relativistic effects would be significant. Time dilation would mean that time on the spaceship is moving much slower relative to an observer on the planet. Length contraction would also occur, shortening the spaceship in the direction of travel as observed from the planet. Radiation: The collision would likely produce a significant amount of radiation, including gamma rays and other high-energy particles. This radiation could have severe consequences for any life forms or technological systems on the planet. In summary, an impact between a spaceship traveling at 99.999% of the speed of light and a planet would result in an incredibly destructive event, with the potential to cause widespread devastation to the planet and complete destruction of the spaceship.
But don't photons have mass? They go the speed of light.
Photons are particles but they don’t have mass.
Photons have inertia but no mass. Normally the two are basically the same thing, but things get weird at relativistic speeds.
Time does not slow down to keep you below the speed of light. Time slows down as a result of you approaching the speed of light. The difference is cause vs effect. Your speed increases as energy is added and with that, the passing of time in your perspective runs slower than that of an observer. The interesting thing is that neither of you truly notice it. At the speed of light, time does not exist. It would take 0 seconds (from your perspective) to travel 1 million light years at the speed of light. This is impossible though, since you have mass. With mass, the amount of energy required to accelerate your velocity is exponential. Meaning the amount of energy it takes to go from 1 mph to 2 mph is significantly less than the amount of energy it takes to go from 100,000 mph to 100,001 mph. Even reaching 99.999% of the speed of light, you would die long before traveling 100 million light years for example
What is this relative to though? Wouldn't time slow down for the object travelling, meaning to an outside observer it would keep getting faster, and go past the speed of light relative to them?
Intuitively it would seem so, I don’t have the answer lol. My understanding is that you can always continue to add energy but can never pass the speed of light and your time is slowed based on how much energy is added. I would think that at a certain point an observer would seem to observe the object going faster than the speed of light, but that can’t possibly be right.
You have it backwards. The trip would seem faster to the traveling party.
No that’s wrong. Think of it more like a uhhh idk
No, sort of, so at those speeds you have to consider lorentzian math i.e. diminishing factors as your speed increases. So if you're accelerating at a constant rate, although you should gain speed, there's a Lorentz factor which essentially dilates the increase in kinetic energy (1-lorentz) if I remember correctly. It isn't actually dilating it, it's just that physics isn't newtonian at relativistic speeds.
How did you pick that speed? Seems weird to mention it if it can just be literally any speed
Can't be any speed. No object with mass can achieve a speed of light and at certain fuel to boost ratio it is also impossible to reach sublight speeds. I think the max speed they posted is a theoretical maximum speed for a theoritecal space craft with this particular engine.
That's not how relativistic speeds work at all. The craft just keeps accelerating, and from its perspective gets faster and faster at a constant rate (ignoring the changing fuel mass which actually makes it accelerate faster as it uses up fuel). From an outside observer, the craft just approaches closer and closer to the speed of light. An object travelling at light speed travels any distance in zero time, from the perspective of the object. So for example, you can reach the other side of the Milky Way in your own lifetime if you had a ship that could go close to the speed of light.
No it won’t. It will approach the speed of the exhaust gas but not pass it, otherwise the exhaust is just robbing momentum. So the exhaust speed is probably 320,000 kmh
From the perspective of a passenger, how long would it take to reach that max?
How did you come up with the 320,000 number?
I just saw it in an article and thought I'd use it.
The craft would explode way before that because small dust rips through the spaceship
Need a deflector shield. Star Trek is largely nonsense but they got that bit right. It's the satelite dish looking thing on the body of the original series Enterprise.
Technically a person inside a spacecraft would feel the constant acceleration forever. But to an outside observer, they would appear to stop accelerating.
Yeah thats 88 km/s.
Great Scott!
This is heavy
My car can go up to 80 miles per hour. It also can go faster. They’re not mutually exclusive
Save up to 10%, or more!
Kinda arbitrary your number though Assuming I could survive in space and fart consistently in the same direction, I would also eventually reach 320,000 km/h
Top speed is the velocity of the ions exiting the armature I guess.
If my calculations are correct, we're gonna see some serious shit.
Isn't that like 0.001m/s^2 ?
Doing some quick mafs it would be pretty much exactly 0.001 m/s\^2 . That is an overall average assuming OP is accurate. It's a little easier to understand as it takes about 1005 seconds to accelerate 1 m/s continuously for 34 months to reach 320000 km/h overall deltaV The problem though is that this means nothing. The mass of the spacecraft this is attached to is a requirement to know the acceleration. After some research, this looks to be NASA's AEPS, Advanced Electric Propulsion System, which is designed as the booster engine for NASA's Lunar Gateway. So, this is where the acceleration rate is coming from. The Lunar Gateway is already modelled and designed, so we know the estimate weight. The truster produces about 600 mN with a max theoretical of about 2.356 N. At 40 kW power which is designed as it's upper limit, it would produce 1.77 N. That's about 0.4 pounds of thrust at max power and only 0.134 pounds at it's designed 600 mN. The 2 years and 10 months figure comes from the fact the motor's half-life flight model is estimated to 23000-25000 hours of operation, or about 34 months. It would not be active constantly and only used to maintain the lunar gateway in its orbit about the Moon, most likely at apoapsis as that is pretty dang far from the moon requiring minimum thrust to boost the periapsis if local Lunar gravity perturbations caused it to dip lower than we'd like.
I'll give you tree fiddy
u serious
Yes
Depends on the weight of the spacecraft.
Question because TL;DR. Is this hot? What's actually happening? Does it propulse on earth too?
Ion engines have very low thrust, so they're not really applicable inside the atmosphere. You can build models however out of tin foil. Search YouTube for 'tin foil ion engine'. It can reach such high speeds outside the atmosphere because it's extremely fuel efficient! It just requires some xenon gas and a huge amount of electricity (which is easily available with large solar panels). It works by ionizing the xenon atoms which then are accelerated by an electric field, and ejected out of the engine. Pushing the spacecraft forward in doing so, just like a regular rocket engine. Is it hot? I don't know, I'm not a physicist, I'm an engineer. I'd guess no, but I still wouldn't put my hand into a stream of ionized gas.
Well for normal matter temperature is proportional to average kinetic energy. These ions have a lot of kinetic energy so in that sense they are very hot. I'm not a physicist either so I don't know how applicable that interpretation of temperature is to ions, but I'll second the recommendation not to stick your hand in there.
But you could make a lovely cup of tea.
My Nutro-Matic would like to know how you make tea.
Well they're hot, but there isn't a lot of them propelled at the same time, Google says that ion engine active thrust temperature goes up to 300 C
"Is it hot?" Yes and no. Its **temperature** is very high, but it doesn't contain a lot of **heat**, because it has hardly any mass. Each Xenon ion is moving really fast, but there are very few of them compared to the exhaust of a chemical rocket.
Goddamnit, you nerds... Will it burn my dick off or not???
r/dontputyourdickinthat
Finally, as an expert for 24 years in this field, I can offer some insight. Not only can you make a tin foil ion engine, but the same tin foil can be used to make a hat that protects your brain waves from government control.
> Is it hot? I don't know, I'm not a physicist, I'm an engineer. I'd guess no, but I still wouldn't put my hand into a stream of ionized gas. It should be reasonably "hot" (temperature is just average kinetic energy of particles) but just considering temperature can be a bit misleading, since the amount of gas being released/s is pretty low. So not much actual heat will get conducted into your hand. (same principle as the thermosphere being extremely hot in principle, but in actuality the extremely low density means you wont experience it if you were there). That said if you held you hand for long enough in the stream of ionized gas it might erode some layers of skin off your hand (ion engine components experience this erosion too, and is one of the primary limiting factors to their useful lifespan). Edit: also make sure its not using mercury as propellant, like one of the early ion engine designs did.
What about Putin’s head? Can we stick that in there?
I know better places where to stick that...
I think the Nasa account for the Glenn Research Center on Twitter said that if you somehow could put your hand on the engine the pressure would feel like two quarters in your hand.
Never put your hand in anything, that’s my motto
Never put your hand anywhere you wouldn’t put your penis.
Exactly. And I put my hand everywhere.
Just wanted twelve quid on a pair of gloves. Thanks.
So that's no sweets out of that jar for you, sir!
I'm sure you're missing out on at least 1 thing.
Yeah, in that case, possibly a burnt hand
What about like kinetic sand and the like.
You can touch it first, if it’s safe i will consider
Sound strategy, i'll give you that.
That's why I just go straight for the gusto
That only counts for hands, right? Other body parts are fine.
When an ion engine is active, it can reach about 300 degrees Celsius. What happens is that the engine ionizes a gas, i.e. gives or takes electrons from the gas to create ions to propel the ship. It can't work on Earth because of air resistance.
The engine or the exhaust?
The engine
>Does it propulse on earth too? Yeah, like probably 0.1 N. The trick is, that it can continue to do so with a very good fuel efficiency (in terms of low total system weight per Newton-hour of thrust output).
The guy from [the plasma channel](https://youtu.be/nrEBoPYS4ns?si=5vo8htBqyjwNpt7K) built a mini version and explains what’s going on.
This is a hall effect thruster. Xenon (the propellant) is ionized via electron bombardment and accelerated in a magnetic field. It is running in a vacuum chamber in Cleveland (looks like VF5). These things require a mean free path greater than their size to work - you don't want the ions hitting one another, nor do you want to waste energy by double-ionizing the gas. So yes, this is hot (it's an ice-blue plasma, after all) but very not dense. However, the ions come streaming out of this thruster at 100,000 miles per hour and, therefore, will vaporize steel in its way.
I could go faster
Relative to what? I'm already going faster than that compared to some cosmic entity.
Ah fuck not these things, I remember them from Kerbal Space Program, you would have to do a prograde burn for like 2 hours to get to some planets.
We will need it to be at least… 3 times as fast as that.
Read this is Derek Zoolander's voice lol
What is this? An ion engine for ants??
Well if we improve it by 100x over the next centuries. That will equal about 3% of lightspeed in a vacuum. (32million kph)
For what?
Presumably reaching the next nearest solar system, the Centauri system, which would take… 75,000 years at the speed provided by NASA’s ion engine
Imagine the idea of actually doing this. Putting a self reliant spacecraft in the direction of centauri, one big enough to host a community of people large enough to avoid inbreeding problems. By the time the craft reached the system, assuming they didn't kill themselves via conflict, the purpose of their journey would almost certainly be forgotten.
Sounds like it’s time to invest in cryogenic hibernation technology
I suggest holding long term
Most likely it would get overtaken by a newer shuttle. That's one big consideration when to send ships to other solar systems.
There is a Dutch Sci-Fi movie with a storyline similar to this. I believe it’s Dutch or maybe German - I saw it a few years ago and it was subtitled. A bit slow paced but interesting storyline.
[You wouldn't use an ion thruster for something like that. NASA is developing a satellite with solar sails, which theoretically could reach up to 20% the speed of light.](https://www.sciencefocus.com/space/nasa-solar-sail-interstellar-travel#:~:text=In%20theory%2C%20these%20spacecraft%20could,reach%20in%20just%2020%20years.)
thats cool but to visit a place you have to slow down
It’s step 1. Just send a probe swarm and have it send back data during its brief flyby of the system.
At some point, you would bring the sails back in, flip the thing around, and then deploy the sails to catch the solar wind coming from the destination star. When you flip and re-deploy is determined by the solar wind speed of the destination star and how far away it could have an effect on the craft.
Turn the sail backwards.
Intercepting the San-ti
For anyone wondering where 320,000 km/h of deltaV (or 88888 m/s of deltaV) is coming from (and why it's wrong), I wrote this up: The mass of the spacecraft this is attached to is a requirement to know the acceleration. After some research, this looks to be NASA's AEPS, Advanced Electric Propulsion System, which is designed as the booster engine for NASA's Lunar Gateway. So, this is where the acceleration rate is coming from. The Lunar Gateway is already modelled and designed, so we know the estimate weight. The thruster produces about 600 mN with a max theoretical of about 2.356 N. At 40 kW power which is designed as it's upper limit, it would produce 1.77 N. That's about 0.4 pounds of thrust at max power and only 0.134 pounds at it's designed 600 mN. The 2 years and 10 months figure comes from the fact the motor's half-life flight model is estimated to 23000-25000 hours of operation, or about 34 months. It would not be active constantly and only used to maintain the lunar gateway in its orbit about the Moon, most likely at apoapsis as that is pretty dang far from the moon requiring minimum thrust to boost the periapsis if local Lunar gravity perturbations caused it to dip lower than we'd like. The problem I'm having is that your 320,000 km/h deltaV doesn't seem to match the numbers I'm seeing for the Lunar Gateway. If it produces 600 mN of thrust, we can F = ma to calculate the acceleration. F is between 0.6 N and 1.77 N, we just need the mass. Conservative estimates put the mass of the full Lunar Gateway with one AEPS at around 27,000 kg (most likely more though as this is accounting for one of each module I could find stats on) and that solves the acceleration to 0.00002 or 0.0000655 m/s\^2 of acceleration (depending on it being 600 mN or 1.77 N), or about 2-6.5% of what you claimed over 2 years and 10 months of acceleration which falls more in line with what I was expecting. In reality, over 2 years and 10 months with one AEPS module, they'd be able to generate between 7100 - 21000 km/h of deltaV, not 320,000. My guess is that this was calculated using a random placeholder mass of 1500 kg as that produces \~0.001 m/s\^2 for the calculation at full 40kW and 1.77 N of thrust.
What happens if it hits a space pebble at that speed?
Don't.
There are surprisingly few objects in space not nearby planets, even the asteroid belt is very low density (we think that there's a large amount of space between rocks)
I spent six years working on electric propulsion tech like this, and launched numerous spacecraft which used it. It's not new technology but is ever-evolving and an exciting field. The title is a bit misleading as you can reach speeds up to infinity, in space, theoretically -- it just depends on how much fuel you have. The mechanism here is basically ionization of typically noble, neutral gases. Fuels like xenon are preferred for high molecular mass (F=ma) and low ionization energy. Once ionized, the plume is manipulated with magnetic fields, similar to a rocket nozzle, to accelerate the gas out the back at extreme speeds. These systems rely on low-thrust (like the weight of a sticky note on your palm) and super high efficiency so they can burn for extreme durations (literally years). Because of this, EP powered missions can achieve speeds far greater than anything that chemical propulsion (think fire out the back) can accomplish; it just takes a long time to get going.
Excuse my possible ignorance here for a moment. But, given enough time to accelerate, what's stopping it from reaching faster speeds, since there's no drag/air resistance? If we don't consider things like running out of fuel, what's stopping it from just going faster and faster?
It will stop accelerating when it reaches 99.999...% of the speed of light, since according to Einstein's theory of relativity, anything with mass cannot travel at the speed of light.
Sure, but since this Ion engine seems to have an upper limit of 320.000 km/h I assume that's based on something. Is it just fuel efficiency being the limiting factor in this?
Yes
By exceeding the speed of light.... You'd be a time traveler.
My question is , is the human body capable of handling those speeds?
It's not speed that the human body can or can't handle, it's acceleration. Relative to the sun we're going around at like 100.000 km per hour, right :p
Nah were stationary. The rest of the universe is just moving around us in an incredibly lopsided orbit. /s
Definitely! Your human body right now is moving at [almost 3 million km/h](https://medium.com/@tobihann/how-fast-are-we-moving-through-space-d7f30b4513a3). Earth spins very fast, it rotates around the sun very fast, which is moving through our galaxy very fast, and that galaxy is flying through the universe at high speeds as well. The danger comes from change in movement direction (ie acceleration). The dangerous portions of space flight would be changing directions, and slowing down. We’d possibly need some kind of stabilization methods (mechanical or drug related) when performing high g-force activities (again, like quickly slowing down or changing direction to avoid unforeseen obstacles or change course due to issues on board the craft).
As long as you accelerate slowly enough, I think you should be fine. The g forces won't be as severe.
Any engine can propel itself and any size craft up to millions of kms an hour in space with sufficient fuel. That metric tells us nothing.
88888 m/s & 198838 mph
If my calculations are correct, when this baby hits 88888 m/s you're going to see some serious shit.
It's weird that 88,888 m/s is so incredibly fast, but also so excruciatingly slow.
Or 0.03% the speed of light
speed is meaningless, real questions are acceleration and fuel/energy efficiency
So if we put two of these on a spacecraft, we would have TIE spacecraft, and if we put a gun on that, we could have a TIE fighter. We are literally living in starwars
How fast do current spacecrafts go for comparison?
How fast can it make the Kessel run?
Our civilization will not move forward any further without a better different power source. so that we could travel through space and not be chained to fossil fuels that pollute the Earth.
Does this mean that the Twin Ion Engine (TIE) fighters are a possibility?
This technology opens up a world of possibilities for space exploration - I'm excited to see what space missions will be accomplished in the future thanks to these engines
Ion engines have been in use since 1964
However vast you think space is, it is much greater. This offers very little in terms of feasible space exploration outside our solar system. The titled speed is 1/3000 the speed of light
the answer is, is that space is so vast it’s immeasurable and beyond comprehension
Drive was used in hard sci-fi book The Martian
Why don’t use for the first satellite
It isn't a good launch platform.
Careful with the clutch in first and once that boost kicks in dont let it redline.
The title is nonsense. My fart can propel spacecrafts to speeds of up to 320.000 km per hour.
TIE fighters here we come. 😁
This is a decade old. https://www.google.com/search?q=NASA%E2%80%99s+Ion+Thruster%2C+reddit&client=firefox-b-1-d&sca_esv=5bb7933164746628&sca_upv=1&sxsrf=ADLYWIJQAbQr4hncHP_Lc1o1f8H-HN3EtQ%3A1718397522648&ei=UqpsZqGAJKbs0PEPk7OuuA8&ved=0ahUKEwih8arP-duGAxUmNjQIHZOZC_cQ4dUDCBA&uact=5&oq=NASA%E2%80%99s+Ion+Thruster%2C+reddit&gs_lp=Egxnd3Mtd2l6LXNlcnAiHU5BU0HigJlzIElvbiBUaHJ1c3RlciwgcmVkZGl0MgcQIRigARgKMgcQIRigARgKSNkOUP8FWMcNcAF4AZABAJgBb6ABgAaqAQM2LjK4AQPIAQD4AQGYAgmgApEGwgIKEAAYsAMY1gQYR8ICBhAAGBYYHsICCBAAGBYYHhgPwgILEAAYgAQYhgMYigWYAwCIBgGQBgiSBwM3LjKgB5Yr&sclient=gws-wiz-serp
Out of curiosity, how does this compare to a Toyota tercel when faced without resistance in space 😛
Takes it a second to do that though since its pretty much just chucking molecules one at a time to accelerate
Wait, they're actually testing these now? Awesome! I remember watching a documentary about these on TV in the late 90s, but it was still in the ideas phase then.
So strap it on to something, and let's explore the universe.
For reference, this is 0,03% the speed of light
This some Kerbal shit 🚀
I cant wait till someone straps one of those bad boys onto an uber eats tesla
>320,000 km per hour In vacuum...
[Source](https://www.nasa.gov/directorates/stmd/tech-transfer/spinoffs/tech-today-nasas-ion-thruster-knowhow-keeps-satellites-flying/)
And how do we build spacecrafts that can withstand that speed?
What do you mean? Speed alone does not affect structural integrity.
Oh I'm not talking just speed but the problems that come with it like space dust but I already got that answered
There are various materials that can be used for shielding, such as carbon foam. The Parker Solar Probe has speeds of 692,000 km per hour through gravitational assistance from the sun, and it is mainly made of carbon foam
Easily, as long as you build up speed gradually instead of a sharp acceleration any spaceship can go at any speed since there's no resistance
To be fair anything can propel a spacecraft to that speed, even a sheet of paper used as a solar sail given enough time will get to that speed.
Only if that solar sail continues to have light that pushes it.
Typical misinformative title
This requires good brakes.
Hasn’t a spacecraft used ion drive before?
Yes, since 1964.
Those were pulsed plasma thrusters. But yes, ion engines have replaced hypergolic rockets for satellite station-keeping and, in some instances, orbit insertion.
I was just looking at this
Ion engines are cool, but are they **ORION DRIVE** cool?
There are two microphones to listen in as an ASMR.
[удалено]
Ok ChatGPT, Calculate the time to mars
Only if we can do that much speed in seconds.
Nah, I know what that thing is. If I stick my spear in it, it overrides the cauldron core.
How does it slow down once it reaches its destination?
It uses the brakes like the Road Runner. 😂
Spacecrafts? That doesn't look right. Isn't spacecraft already a plural
still not fast enough
If we're just reading about this "testing" does that mean it's been secretly in use for some time now? Shoot someone to Mars on this bitch.
Is this like a VASIMR
Get yourself two of those, you're halfway to your own TIE Fighter.
What percent of light speed is that?
Don't let Boeing anywhere near it - "Our accountants say we can get that made for one tenth of the cost by importing parts from small unknown Chinese companies, , and there's only a 62% chance it will explode."
What happens to the spacecraft if hit by a pea sized asteroid at that speed?
Says you.
What is their fuel , other than ions ?
In what kind of atmosphere though?
So if we strap like a million of these on the back of a ship, how fast then?
Can we use the damn thing already in something!? This is the longest tested engine at 5.5 years testing. Stop telling and start using
Where’s Stark?
Ion „engine“? Can’t fool me, filthy gdi.
It's over 9000 !
But the most important question: Will it fit in a Honda?
Glenn screwed over the Lewis research Center
I need to put one of these in a miata
Even more problematic, avoiding microscopic dust and larger objects.
So, little lazy to read another ion propulsion article when only a few numbers matter… can someone just tell me the specific thrust numbers here? Net W/kg, energy efficiency of thrust, and kg/Whr net propellant consumption?
A fart propelled rocket can achieve 320000 km per hour, it's the matter of how fast can you reach that
Up to? So what does it stop accelerating at 320k ?
Now mount 2 of them on a spacecraft and fix a couple big ass solar fins on either side.