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Helium-3 and mining it for fusion engines discussion


GoldForest
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How do you guys think Helium-3 or whatever they name the gas needed for the fusion engines will be mined? I can see only two possibly ways.

1) A ship with collectors has to dive into Jool's atmosphere, possibly deep inside towards the thicker parts of the atmo, and then boost out back into the station's orbit where the gas will be refined. 
or
2) The space station will have a magic vacuum suction device that will automatic suck up the gas without the need to dive into the atmosphere, but the station will have to probably be within 5 to 15K of the atmosphere, just skimming it. 

If anyone else has a suggestion on how else they might do it, I'm open to them, but right now, that's all I can see. 

Also, will we just get straight Helium-3 or will we get something like a gas mixture and have to filter out all the other elements like argon, nitrogen, hydrogen, etc. If so, I can see them adding ways to filter all the elements into separate tanks. Argon/Xenon gas could be filted into takes for Ion engines or plasma engines. Nitrogen could be filtered out for cold gas thrusters (RCS). Hydrogen could be stored for regular chemical rockets, or for use as a less efficient fusion fuel. 

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I can see another way which would be incredibly cool and totally doable... but who knows if they'll do it.

Balloons.

Imagine if it was possible to build a mining base on Jool that floated in the atmosphere on giant hot hydrogen balloons. It would mine the tritium out of the atmosphere, and would be served by craft that fly to and from it.

(Balloons would be so cool, I can think of so many things to do with them...)

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5 minutes ago, Brikoleur said:

I can see another way which would be incredibly cool and totally doable... but who knows if they'll do it.

Balloons.

Imagine if it was possible to build a mining base on Jool that floated in the atmosphere on giant hot hydrogen balloons. It would mine the tritium out of the atmosphere, and would be served by craft that fly to and from it.

(Balloons would be so cool, I can think of so many things to do with them...)

Helium-3 not tritium. Hydrogen is hard to fuse than Helium. 

Anyway, mmm, I can see it. Oh! Wait! 

What if, they allowed us to land on certain spots of Jool with special engines attached? Like, let's say without these engines, we just impact Jool and explode, but with these engines, it allows the station to hover just above the impact zone/model? 

I know it sounds a little scifi magic tech, but in theory if you make a station that can survive the heat and pressure, and have an unlimited fuel source(Pumping Hydrogen from the atmosphere directly into engines) it could work. 

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3 minutes ago, GoldForest said:

What if, they allowed us to land on certain spots of Jool with special engines attached? Like, let's say without these engines, we just impact Jool and explode, but with these engines, it allows the station to hover just above the impact zone/model? 

I know it sounds a little scifi magic tech, but in theory if you make a station that can survive the heat and pressure, and have an unlimited fuel source(Pumping Hydrogen from the atmosphere directly into engines) it could work. 

Jool is supposed to be a gas giant which means that it might not even have a surface, or if it does, it's metallic hydrogen. Being able to survive that kind of pressure is a bridge too far for my suspension of disbelief.

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Just now, Brikoleur said:

Jool is supposed to be a gas giant which means that it might not even have a surface, or if it does, it's metallic hydrogen. Being able to survive that kind of pressure is a bridge too far for my suspension of disbelief.

No, I don't mean a surface, I mean the collision model. If we could land on that through some mean and have a station sitting on the collision mesh, that would be useful. 

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1 minute ago, GoldForest said:

No, I don't mean a surface, I mean the collision model. If we could land on that through some mean and have a station sitting on the collision mesh, that would be useful. 

Ah OK. Nah, I like that even less, unless the engine you're thinking about is a balloon in which case it'd be terrific.

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Just now, Brikoleur said:

Ah OK. Nah, I like that even less, unless the engine you're thinking about is a balloon in which case it'd be terrific.

Balloon or maybe some type of engine that runs off the gas inside the giant itself. 

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In theory you could have a fusion-powered jet using the atmosphere as reaction mass and running off fuel mined from it. That kind of engine would have lots of applications for any planet with an atmosphere and I can't see why it wouldn't work, assuming you can get a sufficiently compact fusion reactor to work of course. Fission engines like that already exist, shame about the radioactive exhaust though.

I still prefer balloons though.

Edited by Guest
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Well, if they allow on rails thrusting, then we could have the ship/processing plant just sitting in the upper atmosphere, sucking in hydrogen and helium, station keeping:

https://futurism.com/esa-ion-thruster-breathes-air

Solar power is enough to overcome drag at earth, Jool may require fusing some of the hydrogen and helium, it should be able to break even/produce a surplus.

That's how I imagine it, something that dips into the upper atmosphere, but not so much

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13 minutes ago, KerikBalm said:

Well, if they allow on rails thrusting, then we could have the ship/processing plant just sitting in the upper atmosphere, sucking in hydrogen and helium, station keeping:

https://futurism.com/esa-ion-thruster-breathes-air

Solar power is enough to overcome drag at earth, Jool may require fusing some of the hydrogen and helium, it should be able to break even/produce a surplus.

That's how I imagine it, something that dips into the upper atmosphere, but not so much

Jool's atmosphere is 200K, and the physically body of it is around 100K? (Impact with the plant's model). The station would have to be far enough down that it got a good vacuum of Helium and Hydrogen. Probably around 120 to 150K at least I would think. 190K could work, but the atmosphere would be thin there. 

Alternatively, instead of being inside the atmosphere, the station could sit at 201K and send down a carbon nanotube attached vacuum well into the atmosphere. 

But this is KSP, not some sci-fi station simulator. 

Best bet would be have a space station at 201K with a VAB attached to itself. Launch a rocket that can withstand the heat and pressure down to 120K, then have it return to the station with full tanks. 

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Who cares if the air is thin? you're traversing 8km of it every second, all day every day... I haven't played around much in Jools atmosphere, but IRL with increasing gravity comes decreasing scale height (as the air is more compacted by gravity). 50km deep in Jool would be very deep. The air on earth is very thin at 200km, but its enough to feed an ion drive that counteracts the drag. In reality, the ISS is orbiting in Earth's atmosphere, I'd say anything below the exobase counts as the atmosphere (still part of the thermosphere), even if its simultaneously considered "space" because its above the karman line.

You want to be deep enough to scoop some stuff up, but you also want to stay at orbital velocity, so your ship's power output needs to be sufficient to counteract drag, and the heating cant be too much.

To me this suggests operating very high in the atmosphere, as air breathing Ion engines (new tech, would have been future tech in the pre-1.0 days... maybe even at 1.0 release) do.

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Not quite true - it's present everywhere, but only gas giants and stars can hold onto it.  So it's present in higher quantities per unit of gas in gas giants.

It's unlikely that trying to mine it from Eve would make sense - but in theory mining it from Kerbin could be worth it.  (Lower setup/running costs, vs. lower output.)

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11 minutes ago, DStaal said:

Not quite true - it's present everywhere, but only gas giants and stars can hold onto it.  So it's present in higher quantities per unit of gas in gas giants.

It's unlikely that trying to mine it from Eve would make sense - but in theory mining it from Kerbin could be worth it.  (Lower setup/running costs, vs. lower output.)

If only gas giants can hold on to it then my point is proven. It's only present realistically on or in gas giants.

I doubt kerbin would have any as Earth has probably less than 1%, so Kerbin would have less than 1%

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9 minutes ago, DStaal said:

Not quite true - it's present everywhere, but only gas giants and stars can hold onto it.  So it's present in higher quantities per unit of gas in gas giants.

It's unlikely that trying to mine it from Eve would make sense - but in theory mining it from Kerbin could be worth it.  (Lower setup/running costs, vs. lower output.)

On earth we get most He-4 from natural gas deposits or cryogenic seperation; He-3 isn't that common on earth for some reason though (pretty sure it's become He-4 is replenished via decay)

Tbh it would be far easier to use D-T fusion than recover He-3 on kerbin; you're paying a mass penalty for shielding (He-3 fusion is aneutronic) but that still lets you get to the outer system where He-3 can be economically recovered.

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1 minute ago, Incarnation of Chaos said:

On earth we get most He-4 from natural gas deposits or cryogenic seperation; He-3 isn't that common on earth for some reason though (pretty sure it's become He-4 is replenished via decay)

Tbh it would be far easier to use D-T fusion than recover He-3 on kerbin; you're paying a mass penalty for shielding (He-3 fusion is aneutronic) but that still lets you get to the outer system where He-3 can be economically recovered.

Helium makes up less than 1% of Earth's atmosphere. In fact, it's less than 1% of 1%. 0.0005%.

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Just now, GoldForest said:

Helium makes up less than 1% of Earth's atmosphere. In fact, it's less than 1% of 1%. 0.0005%.

I'm aware; which is why He obtained this way is hilariously expensive compared to that obtained  from underground deposits. But it's still done; because the same facility is used to make liquid nitrogen/oxygen/argon and they all liquify at different temperatures making seperation much easier. 

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12 hours ago, KerikBalm said:

Who cares if the air is thin? you're traversing 8km of it every second, all day every day... I haven't played around much in Jools atmosphere, but IRL with increasing gravity comes decreasing scale height (as the air is more compacted by gravity). 50km deep in Jool would be very deep. The air on earth is very thin at 200km, but its enough to feed an ion drive that counteracts the drag. In reality, the ISS is orbiting in Earth's atmosphere, I'd say anything below the exobase counts as the atmosphere (still part of the thermosphere), even if its simultaneously considered "space" because its above the karman line.

You want to be deep enough to scoop some stuff up, but you also want to stay at orbital velocity, so your ship's power output needs to be sufficient to counteract drag, and the heating cant be too much.

To me this suggests operating very high in the atmosphere, as air breathing Ion engines (new tech, would have been future tech in the pre-1.0 days... maybe even at 1.0 release) do.

What about low Jool orbit?

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Well, IRL there isn't a sharp cutoff between the atmosphere and space, which is why the ISS needs reboosting, at it still experiences atmospheric drag. Those air breathing ion engines do work in what would be considered low orbit (they'd stay up  a while even if the ion engine is turned off). KSP doesn't do this, but I wouldn't mind if KSP allowed you to collect Helium and hydrogen from low orbit, with collection rate increasing the lower you go. I'm curious how it would handle on rails orbits inside the atmosphere (something you can do now in KSP, as long as the orbit isn't too low)

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21 minutes ago, KerikBalm said:

Well, IRL there isn't a sharp cutoff between the atmosphere and space, which is why the ISS needs reboosting, at it still experiences atmospheric drag. Those air breathing ion engines do work in what would be considered low orbit (they'd stay up  a while even if the ion engine is turned off). KSP doesn't do this, but I wouldn't mind if KSP allowed you to collect Helium and hydrogen from low orbit, with collection rate increasing the lower you go. I'm curious how it would handle on rails orbits inside the atmosphere (something you can do now in KSP, as long as the orbit isn't too low)

Actually, they thought the atmosphere cut off was at 480KM, the ISS is around 350KM, but they recently found that the atmosphere actually extends past the moon. How? A satellite detected a single atom of hydrogen or something. Just a single atom. How far was this satellite? Just inside of the moons orbit iirc. That's crazy. Of course, this single atom could have come from the sun, or from Jupiter for all we know, but scientists are convinced it is from Earth. 

Anyway, I wouldn't mind Star Theory putting a high atmosphere around Kerbin or any other planet. 70KM is the hard limit, but I would say put in soft limit up to 200KM. at 70KM, your station will stay in orbit, but it will continue to collect atmospheric gases like oxygen and nitrogen in large amounts. Go up to 200km and you'll basically be collecting a gram of atmosphere every hour, I feel would be a good compromise. 

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5 minutes ago, GoldForest said:

Actually, they thought the atmosphere cut off was at 480KM, the ISS is around 350KM, but they recently found that the atmosphere actually extends past the moon. How? A satellite detected a single atom of hydrogen or something. Just a single atom. How far was this satellite? Just inside of the moons orbit iirc. That's crazy. Of course, this single atom could have come from the sun, or from Jupiter for all we know, but scientists are convinced it is from Earth. 

Anyway, I wouldn't mind Star Theory putting a high atmosphere around Kerbin or any other planet. 70KM is the hard limit, but I would say put in soft limit up to 200KM. at 70KM, your station will stay in orbit, but it will continue to collect atmospheric gases like oxygen and nitrogen in large amounts. Go up to 200km and you'll basically be collecting a gram of atmosphere every hour, I feel would be a good compromise. 

Do you realise how little air there is? gram per hour? ;)

 

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10 minutes ago, GoldForest said:

Actually, they thought the atmosphere cut off was at 480KM, the ISS is around 350KM, but they recently found that the atmosphere actually extends past the moon.

There is no sharp cut off, that's to be expected.

Consider these images of mars:

1920px-PIA18613-MarsMAVEN-Atmosphere-3UV

Look how far the hydrogen extends before its indistinguishable from the background.

The amount of air decreased exponentially as you get further out, but there's no sharp limit. I think the best definition is to define the limit as the start of the exosphere:

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

Quote

The exosphere ... is a thin, atmosphere-like volume surrounding a planet or natural satellite where molecules are gravitationally bound to that body, but where the density is too low for them to behave as a gas by colliding with each other. In the case of bodies with substantial atmospheres, such as Earth's atmosphere, the exosphere is the uppermost layer, where the atmosphere thins out and merges with interplanetary space. It is located directly above the thermosphere. Very little is known about it due to lack of research. Mercury, the Moon and the Galilean satellites of Jupiter have surface boundary exospheres, which are exospheres without a denser atmosphere underneath.

Quote

If we define the exobase as the height at which upward-traveling molecules experience one collision on average, then at this position the mean free path of a molecule is equal to one pressure scale height.

Quote

In principle, the exosphere covers distances where particles are still gravitationally bound to Earth, i.e. particles still have ballistic orbits that will take them back towards Earth. The upper boundary of the exosphere can be defined as the distance at which the influence of solar radiation pressure on atomic hydrogen exceeds that of Earth's gravitational pull. This happens at half the distance to the Moon (the average distance between Earth and the Moon is 384,400 kilometres (238,900 mi)). The exosphere, observable from space as the geocorona, is seen to extend to at least 10,000 kilometres (6,200 mi) from Earth's surface.

Anyway, when the atmosphere gets too thin, it stops acting like a gas, as the air molecules don't really interact with each other as in a gas, and you can just consider them particules following ballistic orbits, but bound to the Earth by gravity.

Its not too hard to imagine that this will extend to the distance of another object bound to Earth's gravity, no?

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11 minutes ago, KerikBalm said:

 

Its not too hard to imagine that this will extend to the distance of another object bound to Earth's gravity, no?

This is true, plus the atmosphere theoretically extends way past the moon, which is just bizarre to me. Like, you can find earth oxygen atom just floating several hundreds of thousands of miles from the planet... kind of makes you wonder how much atmosphere the earth loses in a year for it to be that far out.

30 minutes ago, Technical Ben said:

Do you realise how little air there is? gram per hour? ;)

 

It was just a spitball answer, not intended to  e taken seriously.

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2 minutes ago, GoldForest said:

This is true, plus the atmosphere theoretically extends way past the moon, which is just bizarre to me. Like, you can find earth oxygen atom just floating several hundreds of thousands of miles from the planet... kind of makes you wonder how much atmosphere the earth loses in a year for it to be that far out.

It was just a spitball answer, not intended to  e taken seriously.

A single atom does not an atmosphere make. That seems to be the confusion.

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