The Effects Of Diamagnetic Launch and Reentry

[Spacescifi]

 

This is definitely a futuristic discussion, as the energy required to make magnetism diamagnetic is not trivial.

Yet the principle is sound... at least I think so.

Step 1: Send a rocket down a magnetic vacuum tube and accelerate it fast enough that it will reach space upon release only needing to do an orbital insertion burn to reach orbital speed.

Usual Problem Solved: Normally a ship would be obliterated from impacting the air at that speed. Solution? Diamagnetism. A magnetic forward hull so powerful that it literally blocks air and plasma from touching it.

What happens? Upon leaving the tube you likely see a ball of fire, as with railguns, but the ship will come out so fast all you will see is a small fireball in the distance as it ascends into the sky.

Reentry: Also solved.

 

Thr heating problem: Can be solved with internal heat sinks, since powerful magnets generate heat, so being a bulky vessel helps here.

Granted it may not be an SSTO, but at least it can land in one piece if it had to.

Bonus landing: If you can make the ship belly diamagnetic as well you could hover over the ocean, or even do a hovering ocean landing, using the water compression against the belly magnetic field to slow you down like a virtual runway.

 

What do you think?

Edited May 12, 2020 by Spacescifi

[K^2]

Your solution is equivalent to "put some padding in the front". The ship still has to accelerate all the air in front of it, which causes rapid deceleration of the ship itself, which destroys the ship, let alone killing the crew. How you push the air is absolutely irrelevant. Air doesn't have the time to get out of the way, so you're pushing, well, not quite everything you sweep up, but a significant fraction of it, which might be as much as a few tons of air per square meter of your craft's cross-section. Conservatively, you'll lose a few km/s of your speed in under a second as you're going through dense layers.

Technically, you can still send cargo to space by shooting it out of a long cannon. There are components that will survive the deceleration of impact with air. It also happens so fast, you barely need shielding. For re-entry, you have to hit atmosphere at a fairly shallow angle to actually give the ship time to decelerate and not kill the crew with G-forces. Because of that, re-entry heat is generated close to the ship over considerable time, and you need significant shielding to prevent your ship from burning down. That profile is the opposite of what you want when firing something into space out of a cannon, though, so instead, you make the angle steep enough to punch through atmosphere in seconds. No crew to worry about, and most of the heat gets generated much further away from the craft due to much thicker shock. You still want something tough and heat-resistant out front, but not a whole lot of it compared to what you want for re-entry.

So magnetic shielding for launch is pointless thrice. It doesn't help with the actual problem, it's not needed in cases where we could still use such launch system, and it would be entirely too heavy to launch even if we could build magnets that strong. Magnetic field has pressure, and maintaining that much pressure would require very thick "walls" indeed.

[Spacescifi]

59 minutes ago, K^2 said:

Your solution is equivalent to "put some padding in the front". The ship still has to accelerate all the air in front of it, which causes rapid deceleration of the ship itself, which destroys the ship, let alone killing the crew. How you push the air is absolutely irrelevant. Air doesn't have the time to get out of the way, so you're pushing, well, not quite everything you sweep up, but a significant fraction of it, which might be as much as a few tons of air per square meter of your craft's cross-section. Conservatively, you'll lose a few km/s of your speed in under a second as you're going through dense layers.

Technically, you can still send cargo to space by shooting it out of a long cannon. There are components that will survive the deceleration of impact with air. It also happens so fast, you barely need shielding. For re-entry, you have to hit atmosphere at a fairly shallow angle to actually give the ship time to decelerate and not kill the crew with G-forces. Because of that, re-entry heat is generated close to the ship over considerable time, and you need significant shielding to prevent your ship from burning down. That profile is the opposite of what you want when firing something into space out of a cannon, though, so instead, you make the angle steep enough to punch through atmosphere in seconds. No crew to worry about, and most of the heat gets generated much further away from the craft due to much thicker shock. You still want something tough and heat-resistant out front, but not a whole lot of it compared to what you want for re-entry.

So magnetic shielding for launch is pointless thrice. It doesn't help with the actual problem, it's not needed in cases where we could still use such launch system, and it would be entirely too heavy to launch even if we could build magnets that strong. Magnetic field has pressure, and maintaining that much pressure would require very thick "walls" indeed.

 

Well deceleration does make sense. The one thing I had not considered.

 

I am not sure which is better, shooting rockets out of cannons for orbital insertion burns once they hit vacuum, or magnetic vacuum tube acceleration.

Likely the cannons are easier to make.

 

It's actually not a bad idea at all.

 

Make an array of launch cannons, firing cone shaped tungsten nose rockets into space. Once an insertion burn is performed the craft can circle in orbit while crew only is sent up to rendezvous in rockets.

Everything else can be launched via cannon.

That's actually a feasible starfleet orbital cobstruction program.

Even easier if you mount the cannons off a mountain.

A mix of nuclear and or chemical power is all you need to power the cannon to pull this off.

 

EDIT: Diamagnetic field is still good for reentry so long ship has internal heat sinks (LH tanks suffice).

Edited May 13, 2020 by Spacescifi

[kerbiloid]

Hot magnets? I want to see this.

[K^2]

18 hours ago, Spacescifi said:

EDIT: Diamagnetic field is still good for reentry so long ship has internal heat sinks (LH tanks suffice).

Note, it's still magnetic field. Material is a diamagnetic, and the effect is called diamagnetic effect or diamagnetism. But nothing special happens to the magnetic field itself. It's all about how matter interacts with said field.

And if you figure out how to generate and maintain said field, maybe? I haven't done the math. But like I said above, making exceptionally strong magnet that's not tearing itself apart is very hard. The stronger the field, the stronger the effective pressure that's trying to make your magnet explode. Even modern superconductor magnets require a support framework that doesn't contribute to the magnetic field, but just to the mechanical strength of the magnet, and what you're suggesting would require magnets several orders of magnitude stronger. The energy density, which is equivalent to mechanical pressure, of the magnetic field is B²/(2μ). So a 1.5 Tesla magnet of a medical MRI tomographer is already generating nearly 9 atmospheres of effective pressure inside the magnet that has to be supported by magnet's walls. Strongest magnets I've worked with were 14T, and despite having a bore barely large enough to fit your hand through, the magnet itself is too heavy to lift because of the amount of superconducting wire and the structural framework required to maintain such a field. Not to mention the cooling tanks of liquid helium and liquid nitrogen that actually house the magnet.

[Spacescifi]

13 minutes ago, K^2 said:

Note, it's still magnetic field. Material is a diamagnetic, and the effect is called diamagnetic effect or diamagnetism. But nothing special happens to the magnetic field itself. It's all about how matter interacts with said field.

And if you figure out how to generate and maintain said field, maybe? I haven't done the math. But like I said above, making exceptionally strong magnet that's not tearing itself apart is very hard. The stronger the field, the stronger the effective pressure that's trying to make your magnet explode. Even modern superconductor magnets require a support framework that doesn't contribute to the magnetic field, but just to the mechanical strength of the magnet, and what you're suggesting would require magnets several orders of magnitude stronger. The energy density, which is equivalent to mechanical pressure, of the magnetic field is B²/(2μ). So a 1.5 Tesla magnet of a medical MRI tomographer is already generating nearly 9 atmospheres of effective pressure inside the magnet that has to be supported by magnet's walls. Strongest magnets I've worked with were 14T, and despite having a bore barely large enough to fit your hand through, the magnet itself is too heavy to lift because of the amount of superconducting wire and the structural framework required to maintain such a field. Not to mention the cooling tanks of liquid helium and liquid nitrogen that actually house the magnet.

 

Well that is why the tech must be futuristic.

 

 

Interestingly.... liquid magnets are possible to make, and may allow for much stronger magnets that won't break.

https://www.google.com/amp/s/www.sciencealert.com/scientists-have-printed-droplets-of-permanently-magnetic-liquid-and-boy-is-it-trippy/amp

If we ever make electromagnetic fluids we can switch the field on or off that will be a game changer.

Edited May 13, 2020 by Spacescifi

[K^2]

Energizing magnets usually takes a bit of time. Again, you can kind of think of it as a pressure vessel. It's not easy to instantly fill a vessel with pressurized gas without risking blowing something up. There is a lot of energy and very strong forces involved in both cases. But it is possible. Even superconductor magnets can be "turned" on and off. Admittedly, "turning" them off is a lot easier. The process is known as quenching; the coil stops being superconducting, and pretty rapidly dumps its energy as heat. The hardest part is not letting magnet melt down in the process.

In terms of technology allowing us to overcome these difficulties, well, that's a complicated topic. Lets use an example with something way simpler than a magnet. (If we gave out prizes for deceptively complex topics, magnets would take my first place nomination with no competition.) Think about using a flywheel to store energy. It's amazingly simple and efficient. Humans have used flywheels since, well, pretty much since they've known what a wheel is. By the time of ancient Greeks, they've done some nifty things with flywheels as temporary energy storage, and it kept finding uses in clocks, trains, gasoline engines, jets, rockets. Modern flywheels can store energy for long time with conversion factors far exceeding these of chemical batteries and they're still cheaper than a battery. So why don't you have one in your phone? Well, it's all about energy density. In order to increase amount of energy a given weight of flywheel can store, you need to spin it faster. And at some point, no known material can survive the centrifugal forces involved. Can we make stronger materials? A bit. But there are limits to how strong forces between atoms can be in principle, and that's all we get to build on.

So lets say you're writing a sci-fi story in which humans are using flywheels for energy storage. If you write a story where we're using them to store energy from solar panels for use at night and to balance grid demand, you're writing near-future sci-fi with very plausible setup. It's probably one of the methods we'll use for storing renewable energy in the near future, unless we come up with something drastically better. If you will write about airliners powered by flywheels made out of spools of extremely strong fiber, you're writing something that's still hard science fiction, but much more speculative. We have fibers that should potentially allow for it, but we have no idea how to make them in sufficient lengths and sufficiently cheap to replace jet fuel. And odds are, we will come up with something better by the time we have this kind of tech. It's sort of a space-elevator kind of tech, and would, in fact, require similar materials. But it's not implausible.

Finally, if you write about personal orbit-capable shuttle size of a car that are powered by a flywheel, you're in Star Wars territory. This would take materials stronger than maximum limits on chemical bonds, meaning, you're dealing with the kind of unobtainium where you might as well be making up whatever you want. Saying that this magical power source is based on a flywheel at this point is contrived, and unless you're writing a comedic space-opera, I wouldn't recommend it.

When we're talking about building absurdly powerful magnets, we're dealing with similar kinds of limitations. We're not just talking about limits of technology, but of material properties. We can push these a lot further than what we can practically make now, but these limits aren't infinite. Past a certain point, it's not just that we don't know how to make these things. It's that if we figure out how to make materials tough enough to handle it, we'll have better ways of dealing with the problem you're trying to solve. Way, way better ways, which if you want to write into a sci-fi, you might as well treat as magic, because it goes outside of our core understanding of physics. At that point, anything you come up with might as well be magic, so there is no reason to try and explain it with magnets. Unless, of course, you're intentionally going for that Joules Verne style of sci-fi that's so naive, it actually becomes kind of charming.

[kerbiloid]

Curie temperature of materials^[2][3][4]

Material	Curie temperature (K)
Iron (Fe)	1043
Cobalt (Co)	1400
Nickel (Ni)	627
Gadolinium (Gd)	292
Dysprosium (Dy)	88
Manganese bismuthide (MnBi)	630
Manganese antimonide (MnSb)	587
Chromium(IV) oxide (CrO2)	386
Manganese arsenide (MnAs)	318
Europium oxide (EuO)	69
Iron(III) oxide (Fe2O3)	948
Iron(II,III) oxide (FeOFe2O3)	858
NiO–Fe2O3	858
CuO–Fe2O3	728
MgO–Fe2O3	713
MnO–Fe2O3	573
Yttrium iron garnet (Y3Fe5O12)	560
Neodymium magnets	583–673
Alnico	973–1133
Samarium–cobalt magnets	993–1073
Strontium ferrite	723

[Spacescifi]

5 hours ago, K^2 said:

Energizing magnets usually takes a bit of time. Again, you can kind of think of it as a pressure vessel. It's not easy to instantly fill a vessel with pressurized gas without risking blowing something up. There is a lot of energy and very strong forces involved in both cases. But it is possible. Even superconductor magnets can be "turned" on and off. Admittedly, "turning" them off is a lot easier. The process is known as quenching; the coil stops being superconducting, and pretty rapidly dumps its energy as heat. The hardest part is not letting magnet melt down in the process.

In terms of technology allowing us to overcome these difficulties, well, that's a complicated topic. Lets use an example with something way simpler than a magnet. (If we gave out prizes for deceptively complex topics, magnets would take my first place nomination with no competition.) Think about using a flywheel to store energy. It's amazingly simple and efficient. Humans have used flywheels since, well, pretty much since they've known what a wheel is. By the time of ancient Greeks, they've done some nifty things with flywheels as temporary energy storage, and it kept finding uses in clocks, trains, gasoline engines, jets, rockets. Modern flywheels can store energy for long time with conversion factors far exceeding these of chemical batteries and they're still cheaper than a battery. So why don't you have one in your phone? Well, it's all about energy density. In order to increase amount of energy a given weight of flywheel can store, you need to spin it faster. And at some point, no known material can survive the centrifugal forces involved. Can we make stronger materials? A bit. But there are limits to how strong forces between atoms can be in principle, and that's all we get to build on.

So lets say you're writing a sci-fi story in which humans are using flywheels for energy storage. If you write a story where we're using them to store energy from solar panels for use at night and to balance grid demand, you're writing near-future sci-fi with very plausible setup. It's probably one of the methods we'll use for storing renewable energy in the near future, unless we come up with something drastically better. If you will write about airliners powered by flywheels made out of spools of extremely strong fiber, you're writing something that's still hard science fiction, but much more speculative. We have fibers that should potentially allow for it, but we have no idea how to make them in sufficient lengths and sufficiently cheap to replace jet fuel. And odds are, we will come up with something better by the time we have this kind of tech. It's sort of a space-elevator kind of tech, and would, in fact, require similar materials. But it's not implausible.

Finally, if you write about personal orbit-capable shuttle size of a car that are powered by a flywheel, you're in Star Wars territory. This would take materials stronger than maximum limits on chemical bonds, meaning, you're dealing with the kind of unobtainium where you might as well be making up whatever you want. Saying that this magical power source is based on a flywheel at this point is contrived, and unless you're writing a comedic space-opera, I wouldn't recommend it.

When we're talking about building absurdly powerful magnets, we're dealing with similar kinds of limitations. We're not just talking about limits of technology, but of material properties. We can push these a lot further than what we can practically make now, but these limits aren't infinite. Past a certain point, it's not just that we don't know how to make these things. It's that if we figure out how to make materials tough enough to handle it, we'll have better ways of dealing with the problem you're trying to solve. Way, way better ways, which if you want to write into a sci-fi, you might as well treat as magic, because it goes outside of our core understanding of physics. At that point, anything you come up with might as well be magic, so there is no reason to try and explain it with magnets. Unless, of course, you're intentionally going for that Joules Verne style of sci-fi that's so naive, it actually becomes kind of charming.

 

I see.... well you make interesting points.

 

Namely that the point I put an idea to paper it is either beyond anything we know how to do or will require answers to questions we have not even asked in earnest yet.

Thus using fiction is totally justifiable and I tend to agree.

 

I am aware that doing scifi stuff by it's very definition will allow all sorts of stuff I cannot even imagine.

 

Namely warping of space vacuum according to current science requires on paper negative matter... which only exists on paper that we know of.

And dark energy is so mysterious that we literally call it that because we assume it must be a force we just are not aware of.

At any rate I think the key to ALL scifi tech lies in small manipulation rather than big.

 

The better one is at sewing the better garment they can make, rather than tying knots and calling it good.

Interestingly, a single fish is far more a conplex creature than a star, which is just a bunch of mass inducing a fusion reaction.

 

 

I do not know the future tech at all, but I take ideas I wish we had that I like and incorporate them.

Edited May 14, 2020 by Spacescifi

[K^2]

This is actually another good example, yeah. The reason space-time warp for FTL is such an interesting topic for science fiction is because a) it absolutely works on paper, and b) while known limitations seem very restrictive, we don't know if they are real limitations. Or rather, exactly how far out the boundaries let us go. There's a lot of physics and math involved that I don't want to get into, but the main observation is that our universe is currently expanding at FTL speeds. So this whole "bend space to go faster than light" isn't working just on paper. It's happening. And there are a lot of reasons for why universal expansion is getting away with blatant violation of everything physicists claim is a strict law. The fact that universe is very big, filled with dark energy, whatever that is, and is currently in a process of rather violent explosion that we can't fully appreciate based on the time scales we're dealing with, see the being very big note, are all playing a major role here. Which is why we don't normally think of these loopholes as practical, but they're there, and even to a dogmatic scientist the speculation on what might be possible is too hard to resist.

This is probably why hard sci-fi is so difficult to get right. Scientists are pants at writing and writers are pants at science. Go figure, right? And we kind of speak different languages in terms of what's plausible. It's very hard for a real scientist to say, "No, this is impossible." I mean, there are definitely cases where that's something you say, because it's close enough. But then overwhelming majority of things will be either called "likely", because there's existing principles and some lab work that indicates we can do this, or "unlikely", because we don't know how that'd work. And "likely" is great, because if you're working on near-future fiction, that's what you want to hold on to. Things that probably will come to be, unless we stumble on something better, but "unlikely" is a mixed bag. Because it's a very loose word and can apply to a wide range of plausibility. If you ever want advice on these things, you probably should be discussing it within context of a setting. Within a setting, anything is possible, but some things are still contrived. A flying wheel powering a starship is contrived, because if you can deal with materials of that super-strength and these levels of energy, a black hole reactor makes way more sense. But that's an extreme example. We like warp for FTL because it works. Hyperspace is worse, because while it's just as plausible, we see no evidence of it, so it's a bit like door to Narnia. Yeah, maybe we just haven't found it, but then if your story relies on that, then you just picked up a bit of "what if" fantasy feel. And maybe that's fine if it works with your setting! And then if your setting is sufficiently wild, then maybe you fold space through power of clairvoyance granted to you by a drug secreted by giant worms only found on one planet in a galaxy. And this would feel extremely contrived if that's all Melange did. But it's not. It's a central element to how much of society functions, whether they realize it or not, and drives the entire plot.

It's hard for me to view sci-fi purely through eye of someone unfamiliar with technology and science behind it. But I think readers get the feel for contrived inventions in bad sci-fi purely through realization that something that powerful doesn't exist in isolation. This is particularly relevant now, when a lot of people remember what life used to be like before smart phones and even before internet. When you introduce a piece of technology, if something it relies on is almost magical, then it will change all of society. And make no mistake, modern processors in phones and laptops are absolute magic from perspective of actual computer manufacturers from 50 years ago. They would tell you that transistors smaller than 100nm are flat impossible, and at any rate, heat generation from a chip that runs at several gigahertz and does trillions of computations per second would have to have a building dedicated to cooling it. So I think, people now better than any time in the past understand, at least subconsciously, the consequences of "magic" technology. If you have to come up with impossible material or drive or energy source, and that's all it does, it will feel contrived, even if it's not that implausible outside the setting. And on the contrary, you can take something absolutely bananas when looked in isolation, stick it in the setting that acknowledges all of its impacts, and you have something that flows, and you still have the choice to go soft or hard on the science in the fiction. For a contrast, consider Dune vs Mass Efect. Dune's Melange and Mass Effect's Element Zero serve fairly similar purpose of explaining a lot of wizardry in the setting. At the same time, Dune is basically a space-opera, despite being pretty descriptive in places, and Mass Effect has elements of hard sci-fi in it.

Anyways, I'm kind of starting to stray off on a tangent from what I was trying to say - setting matters when discussing how well an explanation for something works, and without knowing the setting, it's hard for me to say how contrived something is. Best I can do is point out what sort of "magic" changes to our understanding of technology it would take to make it workable. And sometimes, it's pretty clear to me that these changes would make the task itself obsolete, and I'll call that out. But sometimes, I just don't know if it works without knowing what else is different about your world.

[Spacescifi]

3 hours ago, K^2 said:

This is actually another good example, yeah. The reason space-time warp for FTL is such an interesting topic for science fiction is because a) it absolutely works on paper, and b) while known limitations seem very restrictive, we don't know if they are real limitations. Or rather, exactly how far out the boundaries let us go. There's a lot of physics and math involved that I don't want to get into, but the main observation is that our universe is currently expanding at FTL speeds. So this whole "bend space to go faster than light" isn't working just on paper. It's happening. And there are a lot of reasons for why universal expansion is getting away with blatant violation of everything physicists claim is a strict law. The fact that universe is very big, filled with dark energy, whatever that is, and is currently in a process of rather violent explosion that we can't fully appreciate based on the time scales we're dealing with, see the being very big note, are all playing a major role here. Which is why we don't normally think of these loopholes as practical, but they're there, and even to a dogmatic scientist the speculation on what might be possible is too hard to resist.

This is probably why hard sci-fi is so difficult to get right. Scientists are pants at writing and writers are pants at science. Go figure, right? And we kind of speak different languages in terms of what's plausible. It's very hard for a real scientist to say, "No, this is impossible." I mean, there are definitely cases where that's something you say, because it's close enough. But then overwhelming majority of things will be either called "likely", because there's existing principles and some lab work that indicates we can do this, or "unlikely", because we don't know how that'd work. And "likely" is great, because if you're working on near-future fiction, that's what you want to hold on to. Things that probably will come to be, unless we stumble on something better, but "unlikely" is a mixed bag. Because it's a very loose word and can apply to a wide range of plausibility. If you ever want advice on these things, you probably should be discussing it within context of a setting. Within a setting, anything is possible, but some things are still contrived. A flying wheel powering a starship is contrived, because if you can deal with materials of that super-strength and these levels of energy, a black hole reactor makes way more sense. But that's an extreme example. We like warp for FTL because it works. Hyperspace is worse, because while it's just as plausible, we see no evidence of it, so it's a bit like door to Narnia. Yeah, maybe we just haven't found it, but then if your story relies on that, then you just picked up a bit of "what if" fantasy feel. And maybe that's fine if it works with your setting! And then if your setting is sufficiently wild, then maybe you fold space through power of clairvoyance granted to you by a drug secreted by giant worms only found on one planet in a galaxy. And this would feel extremely contrived if that's all Melange did. But it's not. It's a central element to how much of society functions, whether they realize it or not, and drives the entire plot.

It's hard for me to view sci-fi purely through eye of someone unfamiliar with technology and science behind it. But I think readers get the feel for contrived inventions in bad sci-fi purely through realization that something that powerful doesn't exist in isolation. This is particularly relevant now, when a lot of people remember what life used to be like before smart phones and even before internet. When you introduce a piece of technology, if something it relies on is almost magical, then it will change all of society. And make no mistake, modern processors in phones and laptops are absolute magic from perspective of actual computer manufacturers from 50 years ago. They would tell you that transistors smaller than 100nm are flat impossible, and at any rate, heat generation from a chip that runs at several gigahertz and does trillions of computations per second would have to have a building dedicated to cooling it. So I think, people now better than any time in the past understand, at least subconsciously, the consequences of "magic" technology. If you have to come up with impossible material or drive or energy source, and that's all it does, it will feel contrived, even if it's not that implausible outside the setting. And on the contrary, you can take something absolutely bananas when looked in isolation, stick it in the setting that acknowledges all of its impacts, and you have something that flows, and you still have the choice to go soft or hard on the science in the fiction. For a contrast, consider Dune vs Mass Efect. Dune's Melange and Mass Effect's Element Zero serve fairly similar purpose of explaining a lot of wizardry in the setting. At the same time, Dune is basically a space-opera, despite being pretty descriptive in places, and Mass Effect has elements of hard sci-fi in it.

Anyways, I'm kind of starting to stray off on a tangent from what I was trying to say - setting matters when discussing how well an explanation for something works, and without knowing the setting, it's hard for me to say how contrived something is. Best I can do is point out what sort of "magic" changes to our understanding of technology it would take to make it workable. And sometimes, it's pretty clear to me that these changes would make the task itself obsolete, and I'll call that out. But sometimes, I just don't know if it works without knowing what else is different about your world.

 

I do appreciate when you call out an idea that would be lethal.

Usually happens when I try to use real science, for I have little need for science when I make up everything on the fly.

So thank you.

I really thought I had a good thing going with the magnetic field, but did not take into account the g-force from air impact.

It's ironic really, since for all the slowing when astronauts come down dyring reentry they are pulled back into their seats, not pulled forward, right? Since the air is slowing gradually as they continue to fall along a curve.

But if they took a steep or head on dive... yeah... that's braking on steroids and fiery death. 

As for making stuff up, I do think it is fine considering implications so long they have an effect on how things hapoen in the story.

 

All the contrivance in the world of a fictional device is an absolute waste of tge reader's time if it does not have some or a lot of bearing in the plot.

In my opinion. I am not someone who thinks knowing the A to Z of a fictional empire is something that needs the reader's attention. Unless it bears on the events that happen in the story.

Otherwise do not do that.

Or at least I won't in my SF.

 

 

[Hannu2]

You encounter first problem very soon. I recommend to make some studies at moderate speeds before actual experiments at "orbital speed + huge aerodynamic losses" velocity range. Oxygen is strongly paramagnetic and therefore air is paramagnetic. All nice magnetic contraptions built to handle diamagnetic fluid, like water, do not work.

 

[Aelipse]

Interesting idea, but my first concern, which has been partially voiced here by others, is that A) air itself is not magnetic, or not magnetic enough to be affected by your magnetic "bubble", and B) while plasma consists of electrically charged particles and is therefore subject to magnetic forces, how do you hope to produce it without having the air touch your ship in the first place?

Edited May 21, 2020 by Aelipse

[Spacescifi]

34 minutes ago, Aelipse said:

Interesting idea, but by first concern, which has been partially voiced here by others, is that A) air itself is not magnetic, or not magnetic enough to be affected by your magnetic "bubble", and B) while plasma consists of electrically charged particles and is therefore subject to magnetic forces, how do you hope to produce it without having the air touch your ship in the first place?

 

An uber (ridiciculously) magnetic field could actually block air from hitting the hull.

I would expect the air in front of the magnetic field to be compressed, thus producing plasma.

Yet magnetic fields of that strength are far beyond our state of the art.

I even know that at too high of levels, magnetic fields liquify stuff (atomic disassembly), but that is neutron or magnestar territory. Meaning magnetic fields alone can kill without metal if powerful enough.

Gruesome way to go.

Edited May 21, 2020 by Spacescifi

[Aelipse]

OK, let's assume that a magnetic field strong enough to repel air molecules themselves could be produced, hypothetically. Other than liquifying the crew and everything else on board, I would be actually quite concerned about its interaction with the Earth's magnetic field. The hypothetical device that would produce such a strong field would probably flip the ship, or whatever is left of it, and bring it soaring towards the closest magnetic pole of the planet.

[Spacescifi]

3 hours ago, Aelipse said:

OK, let's assume that a magnetic field strong enough to repel air molecules themselves could be produced, hypothetically. Other than liquifying the crew and everything else on board, I would be actually quite concerned about its interaction with the Earth's magnetic field. The hypothetical device that would produce such a strong field would probably flip the ship, or whatever is left of it, and bring it soaring towards the closest magnetic pole of the planet.

Well I really do not know the specific field strength required to repel air, but I reckon it is high.

High enough to liquify bodies? I dunno... but if it is any consolation the magnetic field might knock you or unconscious or kill you long before liquification.

The body has electricity so it is susceptible to concentrated magnetism.

May be a way to repel from Earth's poles, as magnets can and do repel.

[Arugela]

5 hours ago, Aelipse said:

Interesting idea, but my first concern, which has been partially voiced here by others, is that A) air itself is not magnetic, or not magnetic enough to be affected by your magnetic "bubble", and B) while plasma consists of electrically charged particles and is therefore subject to magnetic forces, how do you hope to produce it without having the air touch your ship in the first place?

Could cold plasmsa be useful there? Maybe have it burn the oxygen and coat the ship in cold plasma. I would assume there are several ways to go about that.

Edited May 21, 2020 by Arugela

[Aelipse]

On 5/22/2020 at 12:22 AM, Arugela said:

Could cold plasmsa be useful there? Maybe have it burn the oxygen and coat the ship in cold plasma. I would assume there are several ways to go about that.

Strong electric field (high voltage) is the only way to ionise the gas I can think of. Otherwise, plasma is almost always hot (it takes a lot of motion for the electrons and cations to remain unpaired).