Mini magnetosphere radiation shielding for a manned mission

RobS · 2014-03-14 10:36:57

Perhaps I should say duricrust instead of caliche. Duricrust is the more common term, but I think I have heard the word caliche used as well. It doesn't have to be a sea bottom sediment, but it does involve a lot of salt accumulation.

RobertDyck · 2021-03-14 12:11:19

I could start a new topic, or post my question here.

I'm considering mini-magnetosphere as radiation shield for the large ship. My large ship design would aim the engine toward the sun during coast, with the wheel rotating perpendicular to the axis of the ship. That means one side of the ship has sunlight 24/7, while the other side is in permanent shade. The aft side of the wheel would have a water wall on the lower deck, so the entire habitation ring is a giant radiation shelter. The term "habitation ring" comes from Star Trek: Deep Space Nine. The aft side wall of the wheel would have cabin windows, and covered in reflectors to light pipes that lead to oxygen generators. There would also be solar panels (photovoltaic) dangling outward from the aft wall. The forward wall of the ring would also have cabin windows, and covered in radiators. The forward surface and outer surface of the ring would be covered in radiators, shaded by solar panels.

Here's the question. If the ship has a mini-magnetosphere, how will it be oriented? If the magnetic axis is aligned with the ship's rotation axis, then one magnetic pole will be aimed at the Sun. Earth's magnetic poles are close to the rotation poles. Earth's magnetosphere is shaped like an apple, pinching in at the magnetic poles. That provides maximum radiation shielding at the magnetic equator, which is where the Earth is located. Magnetic poles actually accelerate radiation into the poles. Where high speed plasma enters Earth's atmosphere, it excites gas in the atmosphere to create aurora. The ships mini-magnetosphere will also be apple shaped. If the ships magnetic poles are aligned with its rotation, then the aft end will have high speed radiation focused into the main engine and its propellant tank. The forward end of the ship will have high speed radiation focused into the docking hatch and zero-G hub. Propellant tanks could be designed to provide shielding against radiation from the aft end. The zero-G hub will be reception for passengers arriving and departing. Aft of the zero-G hub will be cargo. Aft of the cargo will be propellant and propulsion. Do we place some sort of water tank or other radiation shield forward of the docking hatch while the mini-magnetosphere is in operation?

I had thought of storage containers for dried human shit and concentrated human urine. Detachable containers on the sides of the zero-G hub; between the spokes. Do we move the waste containers to forward of the hub? That would still require something before the waste containers are full. Magnetic field coils may have to be on arms that swing forward for operation, but move out of the way for ships to dock. Do we just put waste containers on those same swing arms? That makes plumbing more complicated.

Alternative is to align the magnetic axis perpendicular to the ship's axis of rotation. So the side of the apple shaped magnetosphere faces the Sun. Poles could be positioned over propellant tanks, just aft of the cargo hold. But if we do that, the magnetic axis should not rotate with the ship. To create currents of plasma orbiting the ship, the magnetic poles should be stable. That would require some sort of counter rotation bearing so the electromagnets don't rotate with the ship. That bearing would not be pressurized, but would require power transfer for the magnets. I'm trying to avoid bearings like that.

GW Johnson · 2021-03-14 13:57:49

Robert:

Why could not your magnetosphere poles be aligned with one particular diameter of your ring, and just rotate with it? I know very little about EM physics, so I do not understand why the magnetic field cannot be rotating. You would still have to have shielding near those poles.

But I'd hazard the guess there would be less leakage of radiation into the magnetic field, simply because the "openings" are moving targets.

Sorry, just my ignorance showing.

GW

RobertDyck · 2021-03-14 14:30:38

GW:

Good point. The magnetic field will trap charged plasma that is solar wind. So the very radiation we are shielding against will make the shield stronger. The charged plasma orbits the ship. But if the axis of rotation itself rotates, at 90° to the plasma, that messes with it. I suppose it could work, but I'm concerned. If the plasma orbits at a distance of several kilometres, that's an orbit with radius that far. Moving the axis of rotation will screw with that orbit. Keeping the poles stable allows the plasma to create Van Allen belts within the mini-magnetosphere. The Van Allen belts will strength it.

Well, if a Solar Proton Even happens, you want to keep the ship aimed ass-end toward the Sun. Since the habitation ring uses shadow shielding, you need to ensure the water wall is oriented so it's shadow protects the entire habitation ring. So during an SPE, ship orientation is even more critical. If an SPE hits, I guess the zero-G hub and cargo hold would just have to be off limits. Because that's where the poles of the magnetic field will direct concentrated radiation. Again, propellant tanks will shield the zero-G hub from radiation coming from the sunward end, but not from the deep-space end.

I like your idea of providing human waste as fertilizer to Mars settlements. Designing the waste containers so they can separate is a great idea! Your idea. I was thinking of placing them on the outside of the zero-G hub between spokes. Perhaps we could "cheat" a little by placing them over the front of the zero-G hub, but with the docking hatch exposed. The docking hatch has to be in the perfect centre of rotation, so a ship can align and dock.

We could even design the liquid waste section of the waste containers to have bladders. I wrote that the water wall would have two pockets to it's bladder: one for potable water, one for grey water. So as passengers have a shower, water is drained from the potable side, processed, then partially processed water (grey water) deposited in the other bladder in the water wall. That means total volume in the water wall never changes. We could do something similar in the waste containers. Two bladders, one for concentrated urine, the other a reservoir of fresh potable water. The ship will recycle water, and food will become shit. Would extra water be needed? If our only supply of water is the water wall, that maximizes radiation shielding for the habitation ring. But it means we have nothing for the zero-G hub until enough human waste accumulates for radiation shielding.

Hmm. Maybe that's just what we need to do. The zero-G hub will be off limits until enough waste accumulates for shielding. And the zero-G hub would be off limits during an SPE. Keep all water in the habitation ring water wall.

Quaoar · 2021-03-17 15:36:41

GW Johnson wrote:

Robert:
Why could not your magnetosphere poles be aligned with one particular diameter of your ring, and just rotate with it? I know very little about EM physics, so I do not understand why the magnetic field cannot be rotating. You would still have to have shielding near those poles.
But I'd hazard the guess there would be less leakage of radiation into the magnetic field, simply because the "openings" are moving targets.
Sorry, just my ignorance showing.
GW

The design of the ship proposed is similar to your rigid baton, with the superconductive coil in the middle and the habitat at one end. So the habitat is far from the magnetic poles, where there is no shielding, and is completely protected even when the ship spins for artificial gravity, with the rotation axis perpendicular to the orbit.

tahanson43206 · 2021-03-17 17:35:12

For Quaoar .... here is where your transition to creating drawings as Void has done would be helpful.

You can (if so inspired) create drawings that can be stored at imgur.com. Imgur.com is helpful to provide a link to the image that you just paste into a message here. The option to look for is "bbcode". You will find it listed as an option after you store your image. I can never remember if it is right or left click, to reveal the link menu, but it is one or the other. Simply click on the bbcode choice and it will be saved to your computer's temporary memory (clipboard).

Log into NewMars forum, create a new post, and paste the link into the new post. Voila! Your image of a baton shaped space vessel will appear for all to see.

(th)

Quaoar · 2021-03-18 10:34:33

tahanson43206 wrote:

For Quaoar .... here is where your transition to creating drawings as Void has done would be helpful.
You can (if so inspired) create drawings that can be stored at imgur.com. Imgur.com is helpful to provide a link to the image that you just paste into a message here. The option to look for is "bbcode". You will find it listed as an option after you store your image. I can never remember if it is right or left click, to reveal the link menu, but it is one or the other. Simply click on the bbcode choice and it will be saved to your computer's temporary memory (clipboard).
Log into NewMars forum, create a new post, and paste the link into the new post. Voila! Your image of a baton shaped space vessel will appear for all to see.
(th)

That's the Ruth Bamford's design: in the middle there's an extendable truss with a superconductive coil.

Last edited by Quaoar (2021-03-18 10:36:39)

tahanson43206 · 2021-03-18 12:40:26

For Quaoar ... Thanks for showing this image in post #57

SearchTerm:Bamford design for spacecraft See Quaoar Post #57 above

(th)

SpaceNut · 2021-03-19 18:29:36

https://courses.lumenlearning.com/physi … peres-law/

http://hyperphysics.phy-astr.gsu.edu/hb … urloo.html

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#51 2014-03-14 10:36:57

Re: Mini magnetosphere radiation shielding for a manned mission

#52 2021-03-14 12:11:19

Re: Mini magnetosphere radiation shielding for a manned mission

#53 2021-03-14 13:57:49

Re: Mini magnetosphere radiation shielding for a manned mission

#54 2021-03-14 14:30:38

Re: Mini magnetosphere radiation shielding for a manned mission

#55 2021-03-17 15:36:41

Re: Mini magnetosphere radiation shielding for a manned mission

#56 2021-03-17 17:35:12

Re: Mini magnetosphere radiation shielding for a manned mission

#57 2021-03-18 10:34:33

Re: Mini magnetosphere radiation shielding for a manned mission

#58 2021-03-18 12:40:26

Re: Mini magnetosphere radiation shielding for a manned mission

#59 2021-03-19 18:29:36

Re: Mini magnetosphere radiation shielding for a manned mission

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