[General Battuta]

The whole "field idea" is based on the concept of a man-made artificial magnetic field that would divert radiant energy from the ship. This would be similar to the Earth's own field, which protects us in a similar fashion. Because you don't have access to unobtanium, use of 10-ft thick lead-cored walls is not an option for a small, nimble space fighter.

Well a magnetic field alone wouldn't do the trick, but a combination of an electrostatic field and a magnetic field would (you'd get both electrons and high-energy nuclei/protons.) However you'd need a lot of advances in high-temperature superconductors (i.e. getting them to work) before that's possible.

And I swear there won't be any small, nimble, one-man fighters in a space war. What possible advantages do they have?

I shall quote!

The notion of a space fighter arises simply from overstretching the analogy between space combat and sea warfare. Aircraft came to dominate over battleships on Earth because they enjoyed speed advantages of orders of magnitude and could move in three dimensions, while surface ships were restricted to two. True, large spacecraft will probably have lower accelerations than small ones, but let’s consider what a space fighter will do for a moment. It would be a small craft designed to deliver missiles to a target out of range of the main fleet and then return to a carrier ship. But why bother returning to the carrier? The fighter is probably nothing more than a glorified chemical-fueled missile anyway, no more sophisticated in principle than the missiles you already expend by the dozen. You can at least double its effective range by replacing the pilot with a computer and turning it into a disposable missile bus (I say at least because the computer will probably mass a lot less than the pilot and the life support systems necessary to sustain him). It may be able to accelerate faster too, since it’s now freed from the restriction of having to not kill the pilot with bone-crushing sustained G forces.

The closest thing one is likely to see to a space fighter in a realistic universe is something like the X-15 DynaSoar. It’s basically a very small one-man armed space shuttle, designed to be lifted into orbit on top of a disposal rocket booster, where it could attack enemy space infrastructure or drop bombs on the planet below and then land like a normal aircraft once it had finished its mission. Such a craft would probably have utility very early in the history of a spacefaring civilization, when it was just starting out.

Glorified missile buses!

[NGTM-1R]

Screw your fields, I have layered aluminium foil.

[Thaeris]

Although referring to the realistic, I would also like to refer to the more fanciful elements which might still be possible. Manned starfighters are one of them.

After all, this thread is all speculation until someone is able to do something therein. As that's not quite happened, your opinion is only just that. No offense, of course.

And a "field generator" is not just useful for the said starfighter, it's potentially vital for space exploration in the near future. Without such a system (unless a different, better one is found), long-range manned missions might prove harrowing to say the least because of radiation poisoning.

[General Battuta]

Although referring to the realistic, I would also like to refer to the more fanciful elements which might still be possible. Manned starfighters are one of them.

After all, this thread is all speculation until someone is able to do something therein. As that's not quite happened, your opinion is only just that.

It is an opinion substantiated by fact. Foresight is certainly not perfect, but this prediction has reasoning to back it.

No offense, of course.

And a "field generator" is not just useful for the said starfighter, it's potentially vital for space exploration in the near future. Without such a system (unless a different, better one is found), long-range manned missions might prove harrowing to say the least because of radiation poisoning.

Water shielding is a good option, as is liquid hydrogen. Magnetic shielding has a number of known problems - this time I'll quote direct from Wikipedia -

Electromagnetic shielding has a number of problems: (1) the fields act in opposite directions on positively and negatively charged particles, so shielding that excludes positively charged galactic cosmic rays will tend to attract negative ions; (2) a very large power supply would be required in order to run the electrostatic and magnetostatic generators, and superconducting materials might have to be used for magnetic coils; (3) the possible field patterns might tend to dump charged particles into one area of the spacecraft.

and I think the most effective solution will probably be a combined suite.

[Thaeris]

Water is very massive. Getting that material into space with current or near-future tech would cost... too much.

And then, you have to propell that high mass... blegh.

Use a reactor to power said generator. The reactor is mounted far from the crew module, probably behind it somewhere. If there's a "field dump," hopefully you could engineer a solution to where it dumps behind the crew module and in some place no-one cares about. As understanding on this issue han not been tried-by-fire, I wouldn't rule out that it alone would be incapable of protecting a ship.

And, eh, my X-Wing is still better than your... thing. 

[General Battuta]

Water is very massive. Getting that material into space with current or near-future tech would cost... too much.

Bad news, buddy. Certain elements of a manned space mission need water. I'll give you one guess. And no, transporting it as lox and hydrogen doesn't work; we have something called conservation of mass. (The idea is since you're hauling this stuff you might as well use it as part of the shielding system.)

There's a reason water is consistently cited as a shielding element by NASA and hard SF writers (Baxter, for instance.) Dismissing it out of hand betrays a lack of research on the topic.

Use a reactor to power said generator. The reactor is mounted far from the crew module, probably behind it somewhere. If there's a "field dump," hopefully you could engineer a solution to where it dumps behind the crew module and in some place no-one cares about. As understanding on this issue han not been tried-by-fire, I wouldn't rule out that it alone would be incapable of protecting a ship.

Apparently you aren't reading the posts.

The magnetic system alone is not reliable. Moreover the issue of generating the field at all requires room-temperature semiconductors and a power system of a type not currently available or feasible.

[Thaeris]

I certainly am reading the posts. But, if this is going to go anywhere... forward on this particular issue in a sensible manner then I believe I am safe citing that we both need to do more research... and then listing accurately the source of that research. Even a link would do.

[General Battuta]

I certainly am reading the posts. But, if this is going to go anywhere... forward on this particular issue in a sensible manner then I believe I am safe citing that we both need to do more research... and then listing accurately the source of that research. Even a link would do.

You want me to cite the fact that space missions need to bring water? That's absurd. As for the rest -

Already done, but if you want more

here for a very positive take on emag shields that says they are not yet feasible

well-cited page that states 'water is probably the best radiation shield of all (for hopefully self-evident reasons)

and an uncited but nonetheless accurate blurb from Wikipedia, as above:

    *

None of these strategies currently provides a method of protection that would be known to be sufficient, while using known engineering principles and conforming to likely limitations on the mass of the payload. The required amount of material shielding would be too heavy to be lifted into space. Electromagnetic shielding has a number of problems: (1) the fields act in opposite directions on positively and negatively charged particles, so shielding that excludes positively charged galactic cosmic rays will tend to attract negative ions; (2) a very large power supply would be required in order to run the electrostatic and magnetostatic generators, and superconducting materials might have to be used for magnetic coils; (3) the possible field patterns might tend to dump charged particles into one area of the spacecraft. Part of the uncertainty is that the effect of human exposure to galactic cosmic rays is poorly known in quantitative terms.

[Tomo]

On top of that, we can look at an extant version of magnetic shield that you previously mentioned, namely the Earth's magnetic field.

This actually channels a fair percentage of high-energy charged particles into the Earth around the poles. You can see the effects of these charged particles impacting into the atmosphere in the far north and far south as Aurora Borealis and Australis.

Thus we can postulate that it's only effective because the poles are nearly to perpendicular to the solar wind, and if it was not then it would be worse than useless.

Finally, we can also look at the behaviour of high-energy charged particles in particle accelerators.
There are some very pretty bubble-chamber pictures, eg:

(Image from Particle Physics UK.)

The spiral tracks are charged particles with relatively low velocity and/or mass compared to their charge, usually created by a collision.
Some spin clockwise and others anticlockwise - this is the difference between positively and negatively charged particles.

Note the fact that they spiral, and the random nature of the final (visible) vector in each spiral.

Finally, there are also many tracks that go straight through and that curve slightly both up and down.
The latter are high-velocity and/or mass compared to their charge. You'll notice that the very strong magnetic field in the chamber has almost no effect on them.

[Herra Tohtori]

While it is true that part of the particles end up at the magnetic poles, most of the charged particles actually ends up milling about in the Van Allen radiation belts. Energetic electrons (and positrons, though likely in lesser quantity) form the outer belt, while the inner belt also has protons in it (as well as small amount of heavier charged particles such as alpha particles).

Here's a nice image of simulated Van Allen belts:



By the way, there's actually been plans to remove the Van Allen belts...

[Akalabeth Angel]

By the way, there's actually been plans to remove the Van Allen belts...

Kill the Northern Lights? Why the hell would they want to do that?

[Herra Tohtori]

No.  I just explained that Van Allen belts and Aurora Borealis/Australis are a different thing.

Part of the charged particles ends up hitting the atmosphere near magnetic polar regions during particularly strong solar storms.

Majority of the charged particles in solar wind ends up trapped in Van Allen belts.

Draining Van Allen belts from these charged particles would not reduce the amount of particles hitting the polar region atmosphere during solar storms.


The reason why draining Van Allen belts would be reduced radiation hazards for both crews and equipment of spacecraft. However, I have my doubts about the changes of actually managing to do it.

[swashmebuckle]

Screw your fields, I have layered aluminium foil.

Exactly.  If aluminum foil can shield my guitar from the dreaded mains hum, surely it can protect an astronaut from some puny cosmic rays.  And if that doesn't work he can learn to dodge, or just take it like a man--I don't see what the problem is here, people.

[Kszyhu]

There are also more exotic concepts, like plasma shields (according to old article from New Scientist website).

[General Battuta]

There are also more exotic concepts, like plasma shields (according to old article from New Scientist website).

I believe those fall under the EM shield category...maybe.