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#26 2022-02-28 15:49:34

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
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Re: Large Ship Radiation Protection

Excellent idea! I forgot about that one. Heard of it for atmospheric entry, hadn't considered it for aerocapture. But it could work.

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#27 2022-02-28 19:43:16

tahanson43206
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Registered: 2018-04-27
Posts: 18,142

Re: Large Ship Radiation Protection

For Quaoar (in particular, but all welcome)....

Scientific American provided a link to download the article you recommended.  Apparently they provided the entire issue.

I filled out a contact form requesting permission to share the article with this group.  It will be several weeks before they get back to me.

In the mean time, I will take requests for access to the article on an individual basis.

Quaoar, I'm wondering if you still have the article you showed us.  If you want to see the pdf file from Scientific American, I can open a direct link for you using the email address you have on file with the forum.

Until I hear a request, or receive permission from Scientific American, I will hold the article here and publish short snippets as seem appropriate.

(th)

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#28 2022-02-28 20:08:41

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 29,310

Re: Large Ship Radiation Protection

The good part is that we do have an ADAPT heat shield to make use of and if we have the extra power to field at the last ditch minutes that we can do it as well. The ADAPT materials needed a frame to hold them an the magnetic rings can do that function as its above the hull.

https://ntrs.nasa.gov/api/citations/200 … 085958.pdf
Atmospheric Models for Aerocapture

https://www.nasa.gov/sites/default/file … tagged.pdf
A Plasma Aerocapture and Entry System for Manned Missions and Planetary Deep Space Orbiters

https://digital.lib.washington.edu/rese … _18961.pdf
Magnetoshell Aerocapture: Advances Toward Concept Feasibility

So the question is how much plasma we have to cause the effect?

Until till the model shield is built and flow I can not tell if its going to have a good amount or not. The field is the right shape for it as designed. It is said in one of the document that a Rotating Magnetic Field forms a magnetized plasma in a magnetic dipole. This plasma fills the dipole, providing, charge exchanging with incoming neutral flow, and dragging on the ambient background. The current design also has the Coil set employed in generating a plasma Magnetoshell. The RMF antennas create a magnetic field that rotates about the axis of symmetry of the steady dipole magnet. Not to mention that I have the Two oscillating current Antennas phased at 90° to create a RMF.

https://arxiv.org/ftp/arxiv/papers/2104/2104.12541.pdf
Feasibility Study of Aerocapture at Mars with an Innovative Deployable Heat Shield

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#29 2022-03-01 13:49:59

tahanson43206
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Posts: 18,142

Re: Large Ship Radiation Protection

Notes from Scientific American article recommended by Quaoar...

References on page 47:

Shielding Space Explorers from Cosmic Rays. Eugene Parker in
Space Weather, Vol. 3, No. 8, Article no. S08004; August 18, 2005.
Presentations from the 2004 NASA workshop on radiation shields
are available at aoss.engin.umich.edu/Radiation
NASA’s own Web site on space radiation is at
www.radiationshielding.nasa.gov

The Author

EUGENE N. PARKER is the world’s leading expert on interplanetary gas and magnetic fi elds. He is best known for hypothesizing and explaining the solar wind in 1958. Now the stuff of textbooks, the idea of a vigorous outfl ow of particles from the sun
was initially so controversial that the Astrophysical Journal
nearly rejected his paper. Parker also developed the modern
theory of the solar magnetic fi eld, including magnetic reconnection. An emeritus physics professor at the University of Chicago
and a member of the National Academy of Sciences, Parker has
received numerous prizes, including the U.S. National Medal of
Science, the Henry Norris Russell Lectureship of the American
Astronomical Society and the Kyoto Prize in Basic Sciences.

This article from 2006 does a pretty good job of laying out the radiation problem to be faced by Large Ship designers.

I was particularly interested in the discussion of the proposal to build an electrostatic shield of about 2 billion volts.

The charge would be sufficient to repel positively charged particles (ie, protons) but it would attract negatively charged particles surrounding the space craft to a distance measured (apparently) in kilometers.

These would be accelerated with tremendous force, so that they would become the energy equivalent of the repelled positively charged particles.

My counter proposal would be to build a layer inside the spherical structure that would be charged to the same 2 billion volts of negative charge.  The result would be a large spherical capacitor.

To my knowledge, no one has studied that configuration, so there is an opportunity for someone with the appropriate tools to do so.

The "solution" might not work, or it might have additional negative consequences, but I'd like to see it studied, so we can know one way or the other.

What seems clear is that such a system would require significant power.

(th)

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#30 2022-03-01 18:24:26

SpaceNut
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From: New Hampshire
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Posts: 29,310

Re: Large Ship Radiation Protection

The static shield comes from particle collisions and rubbing against each other while in the magnetic field. They are coming in from the solar wind and since the ship is facing outward the static plasma will be on the wrong side of the ring to allow for it to be used as a speed reducing factor.

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#31 2022-03-01 18:46:21

tahanson43206
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Registered: 2018-04-27
Posts: 18,142

Re: Large Ship Radiation Protection

For SpaceNut .... re #30

Your guess as to what the static field might be is interesting ...

If you would like to see the pdf article from Scientific American, we can work out a file transfer procedure.

It may help you to see pictures.  The electrostatic field has nothing to do with magnetism.

Think of a Van de Graaff device.  A fabric belt driven by a motor scrapes electrons from a source and delivers them to a destination.

As i write this, I realize I've never thought seriously about how a Van De Graaff device works.  I now realize I don't even know if the electrons are deposited on the metal ball, or if they are removed.

My guess is that they are deposited on the ball, because lightning bolts emanate from the ball when it is sufficiently charged.

Something like that is what the researchers had in mind for a proton repeller, but the voltage needed is on the order of 2 billion volts.

Per Google:

The High Voltage Van de Graaff Generator features a 25 cm diameter sphere that can generate approximately 400,000 volts. The size of the sphere, its rounded edges, and its height from the demonstration table contribute to the high voltages generated.

In space, the article shows the sphere of the Van de Graaff machine floating free of the support pillar needed on Earth.

Footnote:

Van de Graaff generator - Wikipedia
en.wikipedia.org › wiki › Van_de_Graaff_generator
It produces very high voltage direct current (DC) electricity at low current levels. It was invented by American physicist Robert J. Van de Graaff in 1929.
Description · History · Entertainment and educational... · Comparison with other...

From the name, I just assumed the inventor was in Europe.

(th)

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#32 2022-03-01 19:12:29

tahanson43206
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Posts: 18,142

Re: Large Ship Radiation Protection

For SpaceNut .... here's another quote from the article from Scientific American ... it explains how the positive charge would be produced...

Firing a beam of electrons into space causes a positive charge to build up on the spacecraft. This charge repels cosmic rays.
To defl ect particles with energies of up to two gigaelectron-volts, the ship would have to be charged to two billion volts.

My colleague stuck his head into a 0.5-tesla magnetic
fi eld. Any motion of his head produced tiny fl ashes of
light in his eyes and an acid taste in his mouth.

The point of the recollection about the .5 Tesla magnet test was that a magnetic field of that strength obviously has effects inside a human brain. That makes sense, since the human brain operates on very small voltage changes.

The article describes a secondary magnetic field that could (presumably) protect passengers inside the habitat ring, from the powerful field generated by the 20 Tesla protection ring.

(th)

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#33 2022-03-01 19:59:35

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 29,310

Re: Large Ship Radiation Protection

You already mentioned why its a bad idea as the negative to positive lightning bolt would punch a hole in the hull and fry the electronics with in the ship.

The fields are outside and directed outward not inward.....

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#34 2022-03-01 22:00:33

tahanson43206
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Registered: 2018-04-27
Posts: 18,142

Re: Large Ship Radiation Protection

For SpaceNut re #33

The article is well written, and filled with illustrations.  It is available to you upon request.

Your line about what magnetic flux is ** inside ** the winding seems (to me at least) speculative.

I am quite sure that if you perform a simple experiment, instead of depending upon Book Larnin', you will find that ** all ** the flux that exists outside a coil is flowing through the center of the coil, due to a law of nature.  I'm not sure which law of nature is involved, but I'm confident that whichever one it is, it can be relied upon as firmly as Newton's three laws of motion.

In other words, if you have a 20 Tesla field ** outside ** the coil, you will have that exact same 20 Tesla inside the coil.

(th)

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#35 2022-03-02 18:35:26

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 29,310

Re: Large Ship Radiation Protection

A permanent magnet field
MUtOQWcxPp-magneticfieldlines.png?width=1200

or this one

Magnet_Iron_Filings.jpg

Print 2 and place them so the drawing faces out with a pencil in between them and spin like a flip book and watch the field lines create a circle with the top and both becoming more dense such that the closest area would appear solid.

here is a coil of wire but the coil I am making does not wrap around the hull
bar.gif

The magnetic ring that I am starting with has this for a field in image a.
Figure_23_03_02a.jpg

image b and c is just straight piece of wire showing how the field circles it

Since I am applying a coil field around the magnets I am getting this type of field that allows for the hull to be inside away from the field
lines-magnetic-field-B-loop-i.jpg

The electrical produced field also due to it alternating will also turn 90' with respect to the permanent field which then produces a larger outward field due to field summing between fields that are adjacent.

https://www.kjmagnetics.com/blog.asp?p=magnet-grade

https://en.wikipedia.org/wiki/Rare-earth_magnet

Neodymium magnets are the strongest type of magnets that are permanent in nature. These magnets can have a gauss rating over 14,000. Medical magnets that are used in conjunction with MRI machines have a gauss rating between 20,000 and 70,000.

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#36 2022-03-02 20:52:44

tahanson43206
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Registered: 2018-04-27
Posts: 18,142

Re: Large Ship Radiation Protection

For SpaceNut .... thanks for working so hard on this problem!  It is time to put all those theoretical ideas into practice, and to measure the results.  I'll assume that funds are not available to build a working test article.

In order to know how much funding is required, it is time for you (if you are willing) to create drawings of a test article that will allow you to create a magnetic field around a hollow torus.  It is quite possible there is a bicycle or motorcycle tire that is the right size and shape to match the 19 meter width and 238 meter circumference of the Large Ship habitat ring.

I don't know how to measure magnetic flux, but I assume there must be instruments that can perform that service.

You'll need one inside the tire, and one outside.

Your experiment will need to deliver a table of readings, showing magnetic strength inside and outside the tire as you increase current flow.

You have talked about using alternating current instead of direct current.

My recommendation is to plan to test both type of current, so you can provide your audience with facts to work with, in trying to evaluate the success or failure of your design.

(th)

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#37 2022-03-02 21:07:22

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 29,310

Re: Large Ship Radiation Protection

Alternating currents can also be pulsed dc that is cycled in one direction and then reversed by the electric amplifier circuit. The frequencies of the amplifier can go from low under 60 cycle to beyond microwave. This ability to modulate the coils with a variety of pulse duration and frequencies will make the field deflect a variety of ion particles that we might observe.
The microwave foods sometimes come with a little silver paper backed disk for the food to set on its that reflecting that allows for browning of the food or in this case to cause the wave to be reflected back up towards the food once passing through it. So add this to the hull outside which will redirect given frequencies that we might produce with in the field.

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#38 2022-03-02 21:31:38

tahanson43206
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Registered: 2018-04-27
Posts: 18,142

Re: Large Ship Radiation Protection

For SpaceNut re #37

We seem to have an adequate supply of theory built up in this topic.

It is time to perform some physical measurements.  We were surprised by discovery that magnetic fields go right through stainless steel and aluminum foil.  I have no doubt we'll be equally surprised by how physical reality differs from theory from a text book, when you attempt to build a device that deflects high energy ions while NOT causing injury to people a short distance from the powerful fields.

You can start by making a small home experiment, and taking measurements.  Normally (or at least usually), electrical effects scale linearly with dimension and power applied.  The effects (of course) decrease as the square root of distance.

Your experimental apparatus should deliver all needed measurements.

I predict you will find that nothing you do protects the people inside the habitat, or in this case, inside the rubber tire of your experiment.

(th)

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#39 2022-03-03 09:52:21

tahanson43206
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Registered: 2018-04-27
Posts: 18,142

Re: Large Ship Radiation Protection

For SpaceNut re Nuts and Bolts Engineering ... time to set the text books aside....

If you had not demonstrated the ability to work with your hands, and that on some ** very ** challenging tasks, I would hesitate to imagine you could make the transition to a ** real ** hands-on engineer (like GW Johnson).

However, as you approach your 18th Anniversary as a member of the forum, I think there is a chance that all those words, typed into the forum archive over all that time, can transition to a combination of more words and a small amount of ** real ** hands-on work.

The challenge you have accepted is to assume responsibility for radiation protection for the 1060 innocent passengers and crew of Large Ship.  RobertDyck needs the help of thousands of people to pull off the flight of Large Ship, and he has to start with the volunteer efforts of the tiny crew of the NewMars forum.

You have shown us impressive theory.  Now it's time to put all that theory and your skills as a hands-on machinist, to build and test the performance of various ways of warding off cosmic debris as well as Solar Hornets.

Your charge, if you are willing (and able) to accept it, is to design and build test articles, to measure their performance, and to report the results to the forum in the engineering format you've been trained to use.

The first step is to design the test you would like to perform.  It will cost $? to build the equipment, and to acquire test instrumentation, but we cannot know how much funding to raise if we have no idea what you intend to do with it.

You can start by confirming my guess that a bicycle wheel tire might approach the relative dimensions of the Large Ship habitat.

The Large Ship habitat has a width of 19 units by 75 units diameter. 

The ratio of width to diameter is 4 ....

Bicycle wheels come in multiple sizes ... per Google, it appears that they are available in: (inches)28, 27, 26, 24, 20 and 16

The tires themselves come in a variety of widths...

Per Google, a common specification is 700 mm x 23 mm. 

Again per Google, a kid's 20 inch tire looks like: 20 x 1.5- x 2.125 -Kids small 20" wheel, BMX

It might make more sense to just make a hoop with ratio of 19 wide x 75 diameter in whatever materials are at hand, and use ordinary bell wire to make the coil.

You should be able to make some useful measurements, and report them to the forum.

I'll be looking for the intensity of the flux inside the habitat (just inside the coil).

My expectation is that nothing you do will reduce the intensity of the flux, because I am confident there is a law of Nature that says that the flux inside a coil must match the flux outside the coil.

Your experiments will prove or disprove my hypothesis.

If 20 Tesla is needed to ward off cosmic or Solar protons (let alone iron nuclei) then that same 20 Tesla will exist inside the coil.

I am willing to make the Radiation article available, as recommended by Quaoar.

I need your agreement to accept the file.

(th)

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#40 2022-03-03 14:53:09

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 18,142

Re: Large Ship Radiation Protection

For SpaceNut .... I've been skeptical of your insistence that alternating magnetic fields might be effective in dealing with space radiation (ie, charged particles).

However, the article quoted below appears to lend some support to your idea ...

https://getpocket.com/explore/item/whoo … ket-newtab

For the Large Ship radiation topic ...

In support of SpaceNut's theories about AC emissions ...

Pocket worthyStories to fuel your mind
Whoops, Humans Made a Space Barrier Around Earth

The kicker? It’s actually saving us.
Popular Mechanics

    Caroline Delbert

illustration of earth surrounded by shields

Photo by NASA

Forget the Kármán line—there’s a human-made space barrier to wonder about, first observed by NASA in 2017. The mysterious zone of anthropogenic space weather is caused by specific kinds of radio waves that we’ve been blasting into the atmosphere for decades, but experts say the expanding band actually helps protect humankind from dangerous space radiation.

ScienceAlert reports that NASA first observed this belt in 2012. The agency sends probes to explore different parts of our solar system, including the Van Allen Belts: a huge, torus-shaped area of radiation that surrounds Earth. The donut shape follows the equator, leaving the North and South Poles free.

A cross section of Van Allen radiation belts. NASA/Public DomainPhoto by NASA/Public Domain

The Van Allen Belts are related to and affected by the magnetosphere induced by the nonstop bombardment of the sun’s radiation. They affect benign-seeming magnetic effects like the Northern Lights, as well as more destructive ones like magnetic storms.

People planning spaceflight through areas affected by the Van Allen Belts, for example, must develop radiation shielding to protect crew as well as equipment—and most spacecraft launch from as near to the equator as possible, right in the Van Allen zone.

So, what’s our new protective barrier? The same probes that launched in 2012 to help us understand the Belts better in the first place detected this phenomenon, and in 2017, the probes gave us the first evidence of the radio-wave barrier emanating from Earth. ScienceAlert explains:

    “A certain type of transmission, called very low frequency (VLF) radio communications, have become far more common now than in the 60s, and the team at NASA confirmed that they can influence how and where certain particles in space move about.”

Why is this? Well, the very low frequency (VLF) waves are exactly right to cancel out and repel the radiative advances of the Van Allen Belts as a matter of total coincidence. In fact, NASA initially considered this a true coincidence, saying that a radio wave area happened to match exactly with the edge of the Van Allen Belts. But in 2017, the agency published findings revealing that one has caused the other after all.

Typically, services like the military have dibs on very low frequencies. These were the first frequencies to be discovered and used for broadcasting, but successive discoveries pushed private and recreational users further up the spectrum. At the very lowest point is the simplest broadcast, things like Morse code, where only binary values need to be received. After that, VLF used by military equipment, for example, occupies a chunk of wavelengths.

From there, AM is still pretty low, and FM is farther up. Some “regular” bandwidths of civilian-type radio are off limits because they’re used for more traditional radio communications by people like pilots and ship captains for different purposes. Any physical communication like this must be negotiated—remember the government has objected to some 5G ideas because of the conflict with GPS satellite signals.

Isn’t it interesting that VLF blankets the Earth without interfering with literally any other radio signal, for example, or the many other kinds of waves that flow around us all the time, but makes it into space far enough to push away harmful radiation?

This means that, for example, space programs could develop VLF technology to punch holes for spacecraft to travel through. As always, truth is stranger than fiction.

Logo for Popular Mechanics

This post originally appeared on Popular Mechanics and was published December 16, 2020. This article is republished here with permission.

(th)

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#41 2022-03-03 15:17:25

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 18,142

Re: Large Ship Radiation Protection

For SpaceNut re protecting the passengers inside the habitat ...

A few days ago, we used "real Universe" experiment to show that neither stainless steel metal sheet, nor aluminum sheet would prevent magnetic flux from reaching a target on the far side.

However, it occurs to me to wonder if a magnetic material might accept the flux and provide a convenient path for it, so that it does not extend into the habitat.

This too is something you (and anyone) can test in the home workshop ....

The materials you would need would include:

1) Permanent magnet (preferably fairly strong - not a refrigerator magnet)
2) sheet of magnetic material (ie, iron that magnet snaps to with alacrity)
3) Target material ... something that is attracted to the magnet

Procedure:

Place magnetic material in a vice, or otherwise secure it for the experiment.
Place magnet on one side ... it will snap into place
Now for the test: Bring the test article into the vicinity of the strong magnet on the OTHER side of the sheet.

At this point, as I type, I do not know how the experiment will turn out.

Update later on ...

Some of our members (and readers) will recognize the term: Faraday Shield  ... I have seen such a shield in large.

The snippets provided by Google will (hopefully) help to clarify what materials and their positioning will help.

However, we have seen that "conductivity" is not sufficient to prevent penetration of magnetic flux through a material.

Faraday cage - Wikipedia
en.wikipedia.org › wiki › Faraday_cage
A Faraday cage or Faraday shield is an enclosure used to block electromagnetic fields. A Faraday shield may be formed by a continuous covering of conductive ...

Faraday's ice pail experiment · Electromagnetic shielding · Booster bag

People also ask
What does a Faraday shield do?
What can penetrate a Faraday cage?
What type of field does Faraday shield stop?
What is a Faraday cage? | Live Science

www.livescience.com › what-is-a-faraday-cage
Dec 2, 2021 · A Faraday cage is essentially a container, or a shield, that blocks out electromagnetic radiation from across the electromagnetic spectrum, such ...
How it works · Invention · Examples · Cars
Inventor: Michael Faraday

Faraday Cage: What Is It? How Does It Work? - Gamry Instruments
www.gamry.com › application-notes › instrumentation › faraday-cage
The Faraday Shield includes a separate shelf to move a sample to the center of the Faraday cage. If no shelf is available, prop up the sample off the floor of ...

faraday cage - Amazon.com
www.amazon.com › faraday-cage › k=faraday+cage
Results 1 - 48 of 740 · This compact faraday bag is designed to hold smaller items such as a tablet, a phone, or a car smart key.This compact faraday bag is ...

(th)

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#42 2022-03-03 19:45:21

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,310

Re: Large Ship Radiation Protection

https://science.howstuffworks.com/question698.htm]How strong are the magnets in an MRI machine?

The magnet in an MRI system is rated using a unit of measure known as a Tesla. Another unit of measure commonly used with magnets is the gauss (1 Tesla = 10,000 gauss). The magnets in use today in MRI are in the 0.5-Tesla to 3.0-Tesla range, or 5,000 to 30,000 gauss. Extremely powerful magnets -- up to 60 Tesla -- are used in research. Compared with the Earth's 0.5-gauss magnetic field, you can see how incredibly powerful these magnets are.

https://onlinelibrary.wiley.com/doi/10.1002/jmri.10367

Over 500 human subjects have been reported to the FDA to have been evaluated at field strengths of 7 and 8 T without the occurrence of a significant adverse event. Information on the systematic evaluation of the effect of these high magnetic fields on vital signs is not available.
Of our first 130 human subjects (not included in these 25 subjects) exposed to 8 T, one vomited and a few demonstrated changes in their vital signs before and after their high-field exposure.

So high intensity field exposure I would not call short duration with vomiting a nothing as well as it that would give a headach, tinnitus, numbness and veritgo suggests that with contious contact things would get worse...


https://academic.oup.com/ehjcimaging/ar … 30/2399837

MRI results in exposure of the patient to a mixture of static magnetic fields (SMF), time-varying gradient magnetic fields (GMF) typically in the range 10–100 kHz, and pulsed radiofrequency fields (RF) in the MHz range. While for occupational exposures of staff working with or in close proximity to the scanner, SMF is the most relevant. The known risks of using MRI mainly relate to the interaction of magnetic and radiofrequency fields with ferromagnetic and paramagnetic objects (limiting its use on patients with metal objects within the body) and that movement of a person through a strong SMF may induce effects such as vertigo and nausea.

RF may cause some heating of tissue, and GMF are capable of stimulating nerves and muscles; however, in practice, the operation limits are set to minimize these effects. With regard to biological and long-term health effects associated with MRI exposure

https://blink.ucsd.edu/safety/radiation … imits.html

600 G (60mT) Allowed TWA for routine exposure (whole body) (8-hour TWA)
6000 G (600mT) Allowed TWA for routine exposure (extremities) (8-hour TWA)
20,000 G (2T) Whole body ceiling limit (no exposure allowed above this limit)

So its bad to stay in a field contiously 5 G (0.5mT) since it can screw up a implanted cardiac pacemakers

The typical unit operating room is shielded by a faraday cage not only for the operator but also more distance beyond that is required for all others not part of a short testing which could exposure you to levels that would do you harm.

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

A Faraday cage or Faraday shield is an enclosure used to block electromagnetic fields. A Faraday shield may be formed by a continuous covering of conductive material, or in the case of a Faraday cage, by a mesh of such materials.  A Faraday cage operates because an external electrical field causes the electric charges within the cage's conducting material to be distributed so that they cancel the field's effect in the cage's interior. This phenomenon is used to protect sensitive electronic equipment (for example RF receivers) from external radio frequency interference (RFI) often during testing or alignment of the device. They are also used to protect people and equipment against actual electric currents such as lightning strikes and electrostatic discharges, since the enclosing cage conducts current around the outside of the enclosed space and none passes through the interior.

Faraday cages cannot block stable or slowly varying magnetic fields, such as the Earth's magnetic field (a compass will still work inside). To a large degree, though, they shield the interior from external electromagnetic radiation if the conductor is thick enough and any holes are significantly smaller than the wavelength of the radiation.

One Tesla is equal to 10,000 gauss. A 3 T MRI scanner is around 60,000 times stronger than the earths magnetic field which is 0.5 mT or 0.0005 T or 5 gauss.
The earths magnetic field is equivalent to 1/30,0000 th of a Tesla. Where the flux density to equal 1 Tesla is 1 newton force that is created from a 1 m length of wire carrying 1 ampere of current.

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#43 2022-03-03 21:14:13

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 18,142

Re: Large Ship Radiation Protection

For SpaceNut ... first reading ... please note what I predicted ... a Faraday Cage does NOT prevent intrusion of a stable magnetic field ... it only works to block alternative RF waves!

You have proposed alternating the protection field, but I think that doesn't make sense, so you'll have to try harder to explain why you think that is a good idea.

An ion approaching from the Sun will be repelled by one half of a wave, but attracted by the other half.

The net effect will be zero.

On the ** other ** hand, I just posted a report about long wave radio apparently causing a change in the Van Allen Belt, so i'm looking forward to learning more about how that may work.

(th)

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#44 2022-03-03 21:29:52

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,310

Re: Large Ship Radiation Protection

Rotation and movement in the belt is also part of the solution as well as the power and frequency being transmitted and received by the satellites and for the field to sweep as we attract and repel the incoming with each degree of movement the ship as it spins at 3 RPM.

The other part of the large ship is the ring frames have independent coils to also make the timing and frequencies different as required as well and not just the intensity of the RF wave transmitted.

Comparison_satellite_navigation_orbits.svg

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#45 2022-03-04 06:18:02

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 18,142

Re: Large Ship Radiation Protection

For SpaceNut ... simplicity is better ... re #44 ... if you design a complex system it must be maintained for 50 or more years of the ship's life

Your point about the rotation of the ship (and thus of the field) is interesting....

Please design a practical demonstration of your ideas, to see if they hold up in the real-Universe.

Here is a bit more on practical physis ... A powerful permanent magnet arrives from the distributor with a device called a "keeper" installed.  I have such a magnet, and can report my observations here:

The magnet was (is) designed to retrieve objects (like an outboard motor) from the bottom of a lake.

It arrived with soft metal plates installed on the active faces of the magnet.  While the keepers were in place, the magnetic field could not be detected outside the magnet.  With the keepers pried off, the faces of the magnet were exposed, and woe to anyone's fingers that got between the magnet and the nearest magnetic surface.  The magnet is currently installed on the back of a wheelbarrow, where it holds a tool rack.

The test I will perform later today is to see if any of the magnetic flux from the magnet is felt on the other side of the wheelbarrow wall.

I'm expecting the amount of residual flux to be small, if there is any.

***
Regarding your theory about using radio frequency to ward ions away from the ship.  This idea seems well worth pursuing.  I am skeptical, because I do not see how an alternating field could have any effect at all upon the forward movement of a charged particle (an ion).

When the field pushes the particle for an instant, it will pull the next instant, so the net effect is to jiggle the particle, without changing it's course at all.

That is EXACTLY how a microwave oven works.  A water molecule is not symmetrical.  The magnetic moment is distributed unevenly.  When a radio wave passes the water molecule, it pushes the little magnet one way, and when the radio wave changes polarity shortly after, it pulls the little magnet the other way. The water molecule experiences this push-pull motion as thermal activity, and it communicates it's little dance to it's neighbors.

Please design an experiment to show how your proposal for using a non-permanent magnetic field would have any effect whatsoever on the incoming ions.

(th)

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#46 2022-03-04 18:12:08

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,310

Re: Large Ship Radiation Protection

I have seen them https://en.wikipedia.org/wiki/Magnet_keeper

A magnet keeper, also known historically as an armature, is a bar made from magnetically soft iron or steel, which is placed across the poles of a permanent magnet to help preserve the strength of the magnet by completing the magnetic circuit; it is important for magnets that have low magnetic coercivity, such as alnico magnets.

So its attaching the North to south pole shorting it out or making a complete loop for the magnetic flux to flow through the magnets material.

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#47 2022-03-04 18:15:36

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 18,142

Re: Large Ship Radiation Protection

For SpaceNut re topic ... There is the word "Closed" next to this topic ... do you have any idea what that means?

OK ... I asked fluxbb.org and got this answer:

Lock Topic - Resources - FluxBB
fluxbb.org › resources › mods › lock-topic
You've heard of 'closing' topics. Now, you can 'lock' topics. This means that only the original topic author or moderators for that specific forum can read/edit ...

I didn't close the topic intentionally,  but may have done so accidentally.

(th)

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#48 2022-03-04 18:36:57

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 29,310

Re: Large Ship Radiation Protection

The mods and admin can post to it but no one else. I will reset it back to open.

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#49 2022-03-05 08:14:23

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 18,142

Re: Large Ship Radiation Protection

For SpaceNut ... RobertDyck reminded us that his design is pretty well set in stone...

The post I am quoting here was an accidental (I am sure) departure from the theme of the Large Ship (Prime) topic.

SpaceNut wrote:

basically tie 11 starships together in orbit and stuff it with the supplies for surface stay and you end up with the monster we are buiding. That has no support to get it to the surface and no capability to restock or to refuel the large ship for the return home.

However, I would like to encourage you to think about the Radiation Protection system as a separate line of business, with Elon and company a potential customer. The Radiation Protection system we've been discussing has nothing to do with the Large Ship (Prime).  It is external to the habitat, and designed to serve any customer who needs protection from cosmic and solar radiation, beyond the rudimentary water wall that is part of the Large Ship (Prime) concept.

I will move my reply from Large Ship (Prime) ...

(th)

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#50 2022-03-05 08:15:32

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 18,142

Re: Large Ship Radiation Protection

This reply to SpaceNut was moved from the Large Ship (Prime) topic because it was off topic.

tahanson43206 wrote:

For SpaceNut re #1201

Your idea in Post #1201 seems (as I understand it) to be to rig 11 Starships in a ring...

As a suggestion, may I suggest you consider making that 12?  You'll need to maintain momentum balance, and 12 seems (to me at least) to be a better bet than 11.  Any number divisible by 3 or 4 should work.  11 could be made to balance, but why make the lives of your crew more difficult?

Note: if you were to proceed with your idea (which I find quite interesting), then your statement about "no support to get" to the surface seems (to me at least) hard to understand .... why wouldn't you just separate individual Starships from the ring and use them for travel to the surface and back?

Please develop your ideas further ... I'm assuming (hoping!) Post #1201 was just the opening of a remarkable variation on the theme of Large Ship.

Your  suggestion would certain cut down on work required to design Large Ship ... all you'd need to develop is the set of girders that will secure the Starships.

If you look back at the Gyroscope Vessel I was working on, you'll find that I was thinking about almost the exact same concept.

I used Fusion 360 for that work, and show various configurations of Starships.

(th)

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