/sci/ - Science & Math

Anyone?

yes

>>9615758
"Space" doesn't exist.

>>9615758
"Radiation" doesn't exist.

>>9615758
using the momentum to generate a EM field would slow the rotation, you would need to constantly accelerate the station with fuel. Would be easier to catch the radiation with solar panels on a spindle and use that to power the field locally around the torus.

>>9615900
Would solar panels catch catch cosmic rays?
I'm working on some sci fi, but cosmic radiation seems to be a real problem without proper shielding.

>>9615903
>believing NASA's excuses against manned space travel

You could just use water to block radiation, you just need a lot of it

>>9615935
Would be tough using a spacecraft like the one in the pic, with water shielding

>>9615933
Why wouldn't long term exposure to Cosmic rays not affect the human body?

>>9615959
I mean they would but as >>9615935 said just build a water layer or cover your base in a meter of dirt lmao

>>9615968
Seems like an extreme waste of resources when you could make an eletromagnetic shield that wouldn't require you to waste extra energy. "lets have a meter of dirt around the spacecraft"
Like, that's the most retarded idea ever, at least you could use and reuse the water.

>>9615976
I mean it's literally dirt. Just throw it on and have it bake in the sun's light

>>9615935
Fuel depots need water anyway so might as well use it for shielding of the habitats.

>>9615875
No

>>9615758

No. It takes very strong magnetic fields to shield against cosmic rays. Think megawatt class superconducting magnets to cover a small volume. Even Earth magnetic field does not protect us, it is the mass of the atmosphere (10 tons per square meter) that is by far the most important shield.

You need several meters of water/fuel/plastic/soil shielding if you want to stay in space for more than a year, there is no way around that.

>I'm working on some sci fi, but cosmic radiation seems to be a real problem without proper shielding.

Maybe some kind of genetic engineering or evolution leading to high radiation tolerance among the space dwellers? Or advanced medication.

>>9615758

Electromagnetic fields do not stop radiation (they're basically radiation themself).
Matter stops radiation, through absorption.
>sci confirmed very very terrible

>>9615900
Also this is correct. To generate a magnetic field means to have charges in movement. Still, since there's energy stored in a magnetic field, you have to do some work to put a magnetic field on. But when are you exactly doing work, since in space a non accelerated motion have no reason to stop? You're oing work when you are pushing your charge to move in the magnetic field provided by their motion itself (they would rather stop than keep spinning, due to the Lorentz force).
It's a recursive process, but still electromagnetism is full of this kind of loops.

>>9616057

Again: when you're talking about the role played by earth magnetic field in protecting the erth, you're talking aboout the deviation of charged high energetic energetic particles, not of radiation. What save us from radiation (UV, gamma etc...) is the the earth atmosphere (particles, still matter though), i.e. ozone shield.

>>9616057
>>9616040
My bad, I confused electromagnetism with superconducting shielding, earlier I was reading:
https://home.cern/about/updates/2015/08/superconducting-shield-astronauts

>>9615903
Just have lots of stuff around the rotating space station. The shielding and the space station don't need to be attached.

>>9616066

particles are referred to as radiation, too

it is particle radiation, particularly high energy cosmic rays (protons and heavier nuclei) coming from outside our solar system, that is the primary health threat for astronauts

ozone does not protect against these cosmic rays, mass of the atmosphere is what protects us (10 tons per square meter)

similar mass is required for long term space radiation shielding, too

>>9616040
The only radiation you need to shield against is solar radiation. Cosmic radiation actually is worse due to our atmosphere. It would be better to have no shields at all for cosmic rays. For solar radiation 1-2 metres is enough.

>>9616104
The primary danger is solar radiation, high energy cosmic rays are extremely rare and can't be shielded against, shielding actually makes it worse.

>>9616109
>>9616110

not true at all

cosmic rays are ubiquitous and are the main threat for astronauts

shielding only makes things worse for small masses of shielding on the order of <1 ton per square meter and if you have metals in your shield

however if your shield is thick enough to stop secondary radiation and also from light materials so that it does not create much secondaries in the first place, then it is a net positive

and you need it if you want to stay in space for longer than a year

>>9616109

>Cosmic radiation actually is worse due to our atmosphere.

Nonsense, cosmic ray radiation is higher at higher elevations, atmosphere is what protects us

>>9616123
Seems like the best way to live in space is to build a base inside an asteroid you moved or in a moons crust.

>>9615903
just have your water tanks act as the shielding

>>9616123
Not really though, you can live with a thin shield for decades in space. The odds of you dying are similar to somebody with an extremely unhealthy lifestyle on earth, like chain smoking or obesity.

Concerning high energy rays you should read this:

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19990051001.pdf

tl;dr they are relatively insignificant in the context of radiation doses.

>>9616130
Seems like the easiest solution, but rip windows.

>>9616129

yes, any realistic space colony will either have to be underground (does not have to be very deep, tough) or have several meters thick outer walls

>>9616123
High energy cosmic rays kill a few hundred cells, if you are unlucky enough to be hit by one.

Lower energy cosmic rays cause constant radiation affecting all your cells and are the dangerous one.

If a high energy comis rays hits a shield, it will cause lower energy rays.

>>9616139

your source is only talking about a solar particle event (SPE), not galactic cosmic rays

however in the long term (months, years) galactic radiation dominates the radiation dose and is the hardest component to shield against

>Not really though, you can live with a thin shield for decades in space. The odds of you dying are similar to somebody with an extremely unhealthy lifestyle on earth, like chain smoking or obesity.

very much debatable, and that may be acceptable for some stranded astronaut but not for an actual colony

>>9616151

>Lower energy cosmic rays cause constant radiation affecting all your cells and are the dangerous one.

and you need at least several meters of shielding to stop them and all the secondaries

>>9615758
No.

>>9616140
You shouldn't have windows anyway. Even the cupola on the ISS is rarely used because it is a hot bed of radiation due to its windows when the shutters are open.

>>9616158
>several meters of shielding

Personally, I'm fine with that. We can hollow out an asteroid and add rockets and shit to it we need. Use that for shielding, if the asteroid itself isn't hot with radiation.

>>9616169

it is fine for a static colony but can be a big issue for a mobile spaceship because of all the shielding mass you need to move around

>>9616163
Sci fi lied to me!

>>9616140
>[window][water][window]

>>9616155
>acceptable for astronauts but not colony
Safety faggots never find anything acceptable. Safe suicide method is the recommended treatment for that illness.

>>9616179
That isn't a problem.

radiation shielding study for a long term colony on the Moon

5 meters of regolith (7 tons per square meter) needed to reach the same radiation levels as in high natural radiation places on Earth (people live there, tough)

almost 8 meters to reach Earth surface levels, however there may be no need for such perfect shielding

>>9616234

>>9616222

why not?

>>9616234

note that galactic cosmic rays (and not solar radiation or flares) dominates the dose

if you have a shield thick enough to shield GCR (and you better do), solar radiation is not a concern

>>9616241
>default excel graph design
>not using origin
barf

>>9616155
One come from outside the solar system, the other from the sun itself, that's literally the only difference.

>>9616297

significant differences exist in spectrum of the radiation (both higher energy and proton numbers) and also the fact that GCR are omnidirectional and constant while solar events are directional and occur only sporadically

in the end this means that galactic cosmic rays dominate the long term dose for astronauts, see this graph

>>9616241

>>9615892
>>9615876
existence doesn't exist

>>9616305
You are an idiot. The paper is about the sun emitting high energy rays. There is literally no difference between those coming from our sun and those coming from other stars.

>>9616352

>those coming from other stars.

>from other stars.

You think cosmic rays come from other stars? lol

>Composed primarily of high-energy protons and atomic nuclei, they are of uncertain origin. Data from the Fermi Space Telescope (2013)[3] have been interpreted as evidence that a significant fraction of primary cosmic rays originate from the supernova explosions of stars.[4] Active galactic nuclei are also theorized to produce cosmic rays.[5]

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

You dont even know the basics and yet you call me an idiot..

>>9616394
Somebody who needs to quote wikipedia surely is an expert on the matter.

>>9616201
Just surround the entire thing in a fish tank, that way you still have visibility.

>>9616403

nothing wrong with wikipedia for basic scientific facts, you can find sources in citations

and you dont need to be an expert on the matter either

do you also want a review article by an expert to prove that Earth is a globe?

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


>For HZE ions that originate from solar particle events (SPEs), there is only a small contribution toward a person's absorbed dose of radiation. During a SPE, there is such a small amount of heavy ions generated that their effects are limited.

>space will give you cancer
>mars will give you cancer

We sure need that mars colony!

>>9616245
Humans have long ago figured out how to maneuver mass through space.

>>9616432

What kind of an answer is that, lol

Payload mass is a very significant constraint on spaceflight, and if you need to shield the spaceship with lots of mass then your useful payload will quickly plummet and your travel time explodes.

>>9616445
If you think extra mass on a space ship is a problem then you have a mental problem.

hey now

>>9616423
from wikipedia
>As well as deflecting the solar wind, the Earth's magnetic field deflects cosmic rays, high-energy charged particles that are mostly from outside the Solar system. (Many cosmic rays are kept out of the Solar system by the Sun's magnetosphere, or heliosphere.[27]) By contrast, astronauts on the Moon risk exposure to radiation. Anyone who had been on the Moon's surface during a particularly violent solar eruption in 2005 would have received a lethal dose.

>Its magnitude at the Earth's surface ranges from 25 to 65 microteslas (0.25 to 0.65 gauss)

OP, wrap your torus in metal wires run a current through it, enough to create a local EM shield of say, 5 gauss and you will be sweet.

>>9616458

>If you think extra mass on a space ship is a problem then you have a mental problem.

behold, the state of /sci/ in the year of our lord 2018, ladies and gentlemen

I gauss the entire spaceflight industry deeply concerned with keeping payload weight in check is a bunch of morons after all

good for solving that issue for us, your noble piece price will be delivered shortly

>>9616485

>As well as deflecting the solar wind, the Earth's magnetic field deflects cosmic rays, high-energy charged particles that are mostly from outside the Solar system.

Earths magnetic field does not deflect the vast majority of cosmic rays, our atmosphere does. Hence why people who live in high elevations or who fly often get significantly higher radiation doses.

>>9616404
Wouldn't thick glass work better?

>>9616488
>entire spaceflight industry deeply concerned with keeping payload weight in check

No, they are making bigger rockets so they can take even more payload up. Thus, it isn't a problem for them. See, because they already have the answer. This is why you are a monumental fucktard triple brainlet.

Here's a photo of you.

>>9616519
That's just wrong.

The magnetic field is the reason the Earth is not a radiation blasted barren rock like the other planets.

>>9616519
well well, look who can't agree with wikipedia now

>>9616536

>what is payload fraction

bigger rockets will not help you there

>>9616556

>>9616556
>inb4 anon kills himself making 20kg diy rocket

>>9616538

Nope, our atmosphere is the reason for that when it comes to cosmic rays. Magnetic field merely protects the atmosphere from being stripped by solar wind.

>>9616551

I cannot, and you better post some other source because that is just wrong.

>>9615758
Dedicated nuclear powered turbine hooked to a big ass alternator should give you some kind of magnetic field. I'm not an electrical engineer so I'm not sure what level of amperage you'd need to protect you from cosmic rays, or what kind of interference the field would place on your instruments vital to station operations. Just use pneumatic controls for everything I guess

>>9616536

nobody in the spaceflight industry is planning to shield spaceships against cosmic rays, even Musk plans to rely on a quick trip (several months) instead of thick shielding

you dont know what you are talking about and yet call others brainlets

>>9616577
>it is okay.
>a little cancer is fine
>we have a treatment program for you

((()))

>>9616563
>Earths magnetic field does not deflect the vast majority of cosmic rays, our atmosphere does
you source that first, because the atmosphere deflects shit, until you do, I'll maintain wikipedia BTFO'd you

>>9616589
>atmosphere

atmosphere turns cosmic rays into secondary particles (particle shower), and only few of the particles actually reach the ground.

>>9616589

>"On Earth if you measure the radiation dose on the surface and then remove the magnetic field, the radiation dose we get will be doubled," says Atri.

>"But if we keep the same magnetic field and instead reduce the atmosphere by 50 per cent, the radiation dose increases by a factor of ten. So the main shielding is provided by the atmosphere, and the magnetic field is a secondary factor."

http://www.abc.net.au/science/articles/2013/11/15/3886100.htm

>>9616604
is that deflection?

>>9616607
cosmic rays, brainlet

>>9616612

the article is about cosmic rays, moron

>>9616577
Can't we just go to the moon first, pick up some rocks, tie them to the outside of the ship like an aphid lion and THEN take the most fuel efficient path to the planet we wanna go to? That way you don't have to launch out of earth's huge gravity well with all that heavy shielding.

>>9616618

you can, but the most fuel efficient path (the one with least delta-v) is also a long path, so if you want to take a year to get to Mars and decades to go to outer solar system you can afford to have thick shielding, otherwise it is a problem

>>9616616
>http://www.abc.net.au/science/articles/2013/11/15/3886100.htm
>The higher the depth of the planetary atmosphere, the lower the flux of secondary particles will be on the surface.
Secondary particles are not Cosmic, retard.

>>9616622
Not a bad trade-off if you can bring more supplies instead of all that dead weight. In fact, you can set it up so the moon rocks are taken to LEO first by another ship and just hang there until you're ready for the main trip. Am I crazy?

>>9616635

secondary particles caused by cosmic rays, idiot

>>9616618
>hey guys i have an idea how to avoid solar rays on the way to mars we just fly outside of the solar system then come back directly to mars!

>>9616648

not crazy, and you are not the first to propose that due to cosmic ray radiation the future of space colonization will be large, very well shielded but also slow spaceships instead of fast transits

it is a legitimate possibility I guess

>>9616658
ofcourse, and those very fucking few that get through the magnetosphere and hit the atmosphere will propogate further in less atmosphere. But we aren't talking about the progation of secondary particles inside atmosphere, we are talking about cosmic rays from out side the magnetosphere. Hence why in 2005 if anyone was on the moon during the sun fart they were dead and we on earth didn't even get a tickle. YOU GINORMOUS SPASTIC.

>>9616677

You are mixing apples and oranges here, cosmic rays and solar flares, and you are too stupid to even realize it. Magnetosphere can protect our atmosphere against occasional solar eruptions, but then those are not so energetic quite easy to shield against, with the hull of the spaceship or a storm shelter being enough. Magnetosphere does almost nothing against galactic cosmic rays, tough, because they are composed of much heavier nuclei and have higher energies, and the only protection against those is our atmosphere, all 10 tons per square meter of it.

>>9616604
>>9616608
The hydrogen atoms absorb and stop most everything. You want good shielding? Find a way to get more hydrogen atoms closer together as densely as possible. Water vapor in the atmosphere helps a great deal. Plastic works. The best would be something /x/ like metallic hydrogen. If it could actually be made and stay together.

>>9616662
I just wish we had a little bit of industry going on at the moon to help with things, not just some crashed debris and old mission leftovers.

>>9616725

note that such very heavy shielding would be needed only for missions lasting longer than a year, in inner solar system maybe as far as Ceres a conventional ship could still be enough

also if we ever manage to master significantly faster propulsion (nuclear? fusion?) then even outer system flights may be doable under a year, still keeping risk of cancer increase at acceptable 5% or so

>>9616723

rocket fuel such as methane would also be very good shielding

too bad most of it is burned during transfer burn at the beginning of the trip

>>9616693
read a textbook dude really. You are mixing apples and oranges here, pressure and desnity and you are too stupid to realise it. 10 tons per square metre is static pressure, not density.

>The flux of incoming cosmic rays at the upper atmosphere is dependent on the solar wind, the Earth's magnetic field, and the energy of the cosmic rays. At distances of ~94 AU from the Sun, the solar wind undergoes a transition, called the termination shock, from supersonic to subsonic speeds. The region between the termination shock and the heliopause acts as a barrier to cosmic rays, decreasing the flux at lower energies (≤ 1 GeV) by about 90%. However, the strength of the solar wind is not constant, and hence it has been observed that cosmic ray flux is correlated with solar activity.

In addition, the Earth's magnetic field acts to deflect cosmic rays from its surface, giving rise to the observation that the flux is apparently dependent on latitude, longitude, and azimuth angle.

The combined effects of all of the factors mentioned contribute to the flux of cosmic rays at Earth's surface. The following table of participial frequencies reach the planet[62] and are inferred from lower energy radiation reaching the ground[63]

>>9616775

http://www.abc.net.au/science/articles/2013/11/15/3886100.htm

>"On Earth if you measure the radiation dose on the surface and then remove the magnetic field, the radiation dose we get will be doubled," says Atri.
>"But if we keep the same magnetic field and instead reduce the atmosphere by 50 per cent, the radiation dose increases by a factor of ten. So the main shielding is provided by the atmosphere, and the magnetic field is a secondary factor."

>So the main shielding is provided by the atmosphere, and the magnetic field is a secondary factor.
>main shielding is provided by the atmosphere

Just stop posting, brainlet.

>>9616775

I did not mention any density, cant you read? 10 tons per square meter is simply mass of the atmosphere above 1 square meter of Earth surface, a convenient unit of radiation shielding mass. It is neither pressure not density. You are out of your depth here and you know it.

Cosmic ray flux depends on solar cycle and activity, a well known fact, nothing new here and certainly nothing that would contradict my post.

>In addition, the Earth's magnetic field acts to deflect cosmic rays from its surface, giving rise to the observation that the flux is apparently dependent on latitude, longitude, and azimuth angle.

Most of this flux variation comes from deflection of solar particles, not galactic cosmic rays, which are barely affected by magnetic field.

>>9616758
I can't think of anything with a higher hydrogen ratio than methane.(4:1). 3nd best would be stuff like Ammonia or Ethane; both 3:1. I'm not even sure methanium would count. lol

>>9615903
Humans need a lot of water, and water also happens to be fantastic at shielding people from radiation. Consider putting all the stored water in containers that surround the exterior of the habitual modules, or even just holding all the water in a big tank on an arm that maintains a static position between the sun and the habitual part of the station.

Another question, say you're using a constant ion engine for thrust in your travel to another solar system, do you actually need Centripetal force for Artificial gravity? Wouldn't the constant acceleration create it?

>>9618729
A constant ion engine only produces milligees acceleration.

>>9618739
Current ones, though I assume our tech will get better and a more powerful thrust could be obtained. One type would be a plasma engine.

it shouldnt be too difficult to develop radiation shielding that keeps it sufficiently at bay to enable long term survival. combine it with futuristic gene repair / tumor removing medicine that will probably exist within a decade or two and it will not be a problem

creating an EMF for shielding is retarded. the field would have to be extremely strong and would waste huge amounts of energy. also, if you used this method you would have to power it with a strong and abundant energy source such as nuclear fusion, not >>9615903 lmao solar panels

it is redundant anyway since you want to shield your spacecraft sufficiently against meteorites or you are playing russian roulette

>pic related
ISS constantly gets hit by micrometeorites and has very thick multilayered shielding against it around critical components

>>9618781
pic related is a space shuttle window impact. this is also why having windows is a stupid idea and if you do you want to cover them the large majority of time

>>9618781
I think a Whipple shield would be enough against meteorites

>>9618781

micrometeoroid shielding is easy a a relatively light staggered shield is enough to solve the issue completely

on the other hand galactic cosmic ray radiation is very hard to shield and you need several meters of material to reduce it significantly, and several meters on top of that if you want to approach Earthlike levels

>>9616241

I think for sci fi, the Bigelow space station should be an interesting development for ideas. imagine huge expandable space stations

>>9618799
yes

>>9618812
fuck yeah

>>9618894
It has so much potential

>>9618748
You don't understand how rockets work. Ion engines exhaust mass at 20-50 km/sec.
We'll assume a huge improvement and expel matter at 500 km/sec. OK?
The ship is 90% fuel. That is, we have 1 tonne of payload, structure, engines, and fuel tank to hold every 9 tonnes of reaction mass.
The dV we can achieve is 500 * ln (10) = 1151 km/sec. That's insanely high by the standards of chemical rockets, but miserably inadequate for interstellar flight. Alpha Centauri is 1120 years away. If you intend to slow down at the far end, that becomes 2240 years!

Note that time doesn't appear in the basic rocket equation, only mass-ratio and exhaust velocity.
1151 km/sec is one gravity for 32.6 hours or one-thousandths of a gee for 3.71 years.

>>9618946
So what kind of rocket propulsion do you recommend for interstellar travel?

>>9615758
What about using thin layers of lead in the insulation or a material which would convert it to heat and then use the heat?

>>9618970

https://en.wikipedia.org/wiki/Fission-fragment_rocket

https://en.wikipedia.org/wiki/Nuclear_salt-water_rocket

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

these are barely powerful enough for interstellar flight, but it would still take decades or centuries and you can forget about travelling at 1g, you still need a long coasting phase and spinning the craft for artificial gravity

>>9619082

lead is no good for cosmic ray shielding, you need light atoms such as hydrogen in order to keep secondary radiation low

>>9619131
It's good enough for generational ships, so i'll take it.

>>9619136
Oke well in that case, would putting a highly pressurized layer of gas around the area you need to shield work?

>>9619144

hydrogen is a huge pain in the ass to work with, escapes through everything and needs cryogenic cooling

more practical materials may be plastic, methane (doubles as rocket fuel), water or even soil

>>9619144
water seems to be the best shield, and you need it for the trip anyways

>>9619207
It's so stupid. There are a million ways you can die in a space trip, and people are worrying about cancer a couple of decades down the road.

For a permanently settled space station, like an O'Neil cylinder, shielding is also not that much of an issue. For example, you can simply grow the plants all around the spaceship and use the couple of metres of soil as a natural shield.

>>9619207
>>9619194
But all that stuff is heavy and without a space elevator or space assembly it doesn't seem ideal.
Is that how they manage it on the ISS?

>>9619236
Mine it from Enceladus

>>9619236

ISS ignores this issue because astronauts only stay on the station for less than a year and also Earth covers almost half of the sky providing some shielding, thus their cancer risk only rises by a few %

mission to Mars can also be kept under a year in duration so it can also mostly ignore cosmic ray danger (but needs a storm shelter against occasional solar flares)

however, for a deep space ship with total flight time longer than a year you can no longer afford to ignore cosmic ray radiation, that is where thick shielding (several meters) is required

>>9615935
This. It's what we do with our fuel rods in nuclear reactors.

>>9615903
Cosmic rays are just high af energy light rays, mostly

>>9619131
We'll probably improve it significantly as we start building them in large numbers, as things usually do when you start having to work on practical application

>>9619426

not true, cosmic rays are mostly high kinetic energy atomic nuclei, from protons all the way up to heavy ones such as iron, which is why they are such a bitch to shield against

>>9615758
No, you will need ertia.
Lots of ertia.

>>9615876
"low effort bait" doesn't exist

NASA actually tried to generate electricity locally using earth's magnetic field via Lorentz principle. But magnetic field of the earth was so strong that cable just couldnt handle the produced current, thus breaking the cable in half after 10 minutes into testing. So energy isnt the problem if we can find the cable capable of harnessing current of the Earth can produce