Survival on Mars: Radiation & Temperature Challenges

[GTOM]

"I hope we're not making decisions to settle places based on whether or not there's a horizon. As for a sky, this doesn't work?"

If we talk about permanent settlements, whether people feeling comfortable or not, is not negligable.

You need a pretty big tin can to have something like the sky. Yes i can get out, in a big metallic space suit, and see the big nothing (ok, in the vicinity of Earth, not just that), have to stay connected with cables... On Mars, a lighter space activity suit (http://en.wikipedia.org/wiki/Space_activity_suit) and a car with own oxygen and hermetically closed doors is enough.

I think we got pretty accustomed with building high towers in Earth gravity, once we landed on Mars, we can forget rockets, and use regular land vehicles and cranes in order to further expand. I'm not sure but i guess the delta-V needed to spin up asteroids is also enough to land on Mars.
Construct roads, high-railways, build rovers that can go on rought terrain, yes it isn't that easy, but i think it is quite cheap and safe compared to use rockets to travel between asteroids, or manuever them to stabile orbits to connect them.
(Probably spinning won't be a single time investment, it makes docking harder, if the station has a non spinning dock, then regular delta-V is needed to prevent de-spin.)

Zero-g isn't ok for humans for a long time, bones atrophy... at this point we can only speculate, what 1/3 g does to humans, i don't deny, that if they want to return to Earth, it will be challenging... the question is whether the majority of them wants to return, or will be fine with a new place, and heavy training if they want to return?
Of course it is also a good question, whether humans will rather care about mining extraterrestial materials, or migrate in mass in order to find a new home with new possibilities?

 

[Pete Cortez]

"I hope we're not making decisions to settle places based on whether or not there's a horizon. As for a sky, this doesn't work?"

If we talk about permanent settlements, whether people feeling comfortable or not, is not negligable.

Then why assume that a Martian vista is more comfortable than a freefall settlement? At this point, there's far too many unknowns--including whether this is an important point at all--to debate aesthetics.

You need a pretty big tin can to have something like the sky.

You're going to need a big tin can period. Fortunately, there's a bunch of ready to assemble ones floating around the solar system.

I think we got pretty accustomed with building high towers in Earth gravity, once we landed on Mars, we can forget rockets, and use regular land vehicles and cranes in order to further expand.

Except for all the rockets needed to get all that material there in the first place. And what's wrong with rockets?

I'm not sure but i guess the delta-V needed to spin up asteroids is also enough to land on Mars.

From Mars orbit to the surface is four thousand meters per second of delta-v. A 1 g habitat with that sort of spin has a 1.6 million meter radius; at which point we might as well be cracking planets to build megastructures inhabited by quadrillions of people.

Construct roads, high-railways, build rovers that can go on rought terrain, yes it isn't that easy, but i think it is quite cheap and safe compared to use rockets to travel between asteroids, or manuever them to stabile orbits to connect them.

Constructing miles and miles of road is cheaper than throwing nuclear bombs out the back?

(Probably spinning won't be a single time investment, it makes docking harder, if the station has a non spinning dock, then regular delta-V is needed to prevent de-spin.)

1. A non-spinning dock is negligibly less massive than the spinning bulk. While there's still orders of magnitude difference, we don't worry about the slowing of Earth's spin.
2. You can always spin the ship.

Zero-g isn't ok for humans for a long time

Hence spinning.

Of course it is also a good question, whether humans will rather care about mining extraterrestial materials, or migrate in mass in order to find a new home with new possibilities?

I think the better question is what quality of life do humans aspire to have? Quality of life roughly correlates to access to energy and stuff to do things we want to do. There's a ton of energy and stuff in space.

 

[Drakkith]

Pete, I think I'm going to step out of this discussion. Enjoy.

 

[mfb]

From Mars orbit to the surface is four thousand meters per second of delta-v. A 1 g habitat with that sort of spin has a 1.6 million meter radius; at which point we might as well be cracking planets to build megastructures inhabited by quadrillions of people.

That comparison does not work.
Going from Mars orbit to the surface requires a heat shield, parachutes and small rockets with negligible delta_v. And you just need that for humans and things you cannot find on the martian surface. Material there does not need any rocket to get used.
Spinning up a habitat needs rockets for the whole final mass of your structure.

Constructing miles and miles of road is cheaper than throwing nuclear bombs out the back?

Yes. Nuclear weapons are expensive, and you would use them for every trip instead of a one-time investment.

 

[Pete Cortez]

That comparison does not work.
Going from Mars orbit to the surface requires a heat shield, parachutes and small rockets with negligible delta_v.

And you just need that for humans and things you cannot find on the martian surface. Material there does not need any rocket to get used.

My apologies. I meant from Earth orbit to Mars surface.

Spinning up a habitat needs rockets for the whole final mass of your structure.

Or slinging waste material anti-spinward.

Yes. Nuclear weapons are expensive, and you would use them for every trip instead of a one-time investment.

The actual warhead cost is not very high. The W-84 clocked in at $1-2 million per unit for a low production run of around 530. That includes amortization of R&D to produce the warhead in the first place, so it's unclear what the minimum unit cost might have been.

Also, I'm not proposing to use them for "every trip." I'm proposing to use them to spin up the habitat. That isn't the only way to do it[/quote], by the way.

 

[GTOM]

Using nuclear warheads?? Maybe it is only me, but i find this idea terrible...

I think the mass ratio of a non-spinning dock, and the spinning space station isn't negligable, like a car compared to Earth...

Of course rockets are needed, but i don't consider them cheap and more efficient than land travel and construction.
I don't see why hollow out an asteroid, making a large cylinder, build houses, spin the whole thing up, biogenic material collection, the delta-V for that operations, etc would be any easier than landing on Mars and use plane old engineering, and dome construction, and biogenic material collection from air and soil.

Yes having lots of energy is good, but won't make me happy if i have to spend my whole life in a tin can, instead of visiting a dozen cities and villages with my car, make small trips to the wilderness etc. (Energy isn't enough to propel rockets, and you can quickly run out of reactive mass on a small asteroid.) In order to feel good, people don't just need energy, but lots of material stuff also, a planet has magnitudes more material, housing space.

Pete, you mentioned lunar ghost towns... i see the very same possibility with asteroid colonies, once ore is depleted, it will be only a small settlement far away from trade routes... possibly they move the whole mining colony to another not too far asteroid, or desert it.

 

[Pete Cortez]

Using nuclear warheads?? Maybe it is only me, but i find this idea terrible...

I wouldn't necessarily use the exist stockpile. You'd probably want purpose-built explosives that direct as much power to the pusher plates as possible. But why do you find the idea terrible?

I think the mass ratio of a non-spinning dock, and the spinning space station isn't negligable, like a car compared to Earth...

Why wouldn't it be negligible? We're talking about a structure on the order of at least 1,000 times the mass of the ISS.

Of course rockets are needed, but i don't consider them cheap and more efficient than land travel and construction.

And I don't see ground transport cheaper or more efficient than slinging cable.

I don't see why hollow out an asteroid, making a large cylinder, build houses, spin the whole thing up, biogenic material collection, the delta-V for that operations, etc would be any easier than landing on Mars and use plane old engineering, and dome construction, and biogenic material collection from air and soil.

Quite simply, delta-v to and from said destination. Everything else is a second order concern. Is it possible you can think of some combination of Mars and asteroid settlement scenarios in which Mars initially starts at as a better prospect? Certainly. But the moment you start envisioning commerce with the homeworld or the rest of the solar system, Mars (or any other deeply gravitating body) becomes yet another well from which to climb out. And for what? For nothing you can't find in the rubble.

Yes having lots of energy is good, but won't make me happy if i have to spend my whole life in a tin can, instead of visiting a dozen cities and villages with my car, make small trips to the wilderness etc.

End of the day, Americans--on average--spend http://cfpub.epa.gov/eroe/index.cfm?fuseaction=list.listBySubTopic&ch=46&s=343 , so I think this is a very secondary point. However, each habitat offers you on the order of 100 square miles of surface area. You can have as many as you want to build. So build yourself a bunch of wilderness habitats. Drive around inside these colonies all you'd like, and simply hop a cable ferry over to the others in the bunch. We're basically talking about constructing an archipelago in space.

(Energy isn't enough to propel rockets, and you can quickly run out of reactive mass on a small asteroid.)

So get a large asteroid. Or many asteroids of many different sizes. The whole point is to exploit resources throughout the solar system. There's 6e20 kg worth of material in the Jupiter trojans.

In order to feel good, people don't just need energy, but lots of material stuff also, a planet has magnitudes more material, housing space.

All of it stuck at the bottom of a gravity well.

Pete, you mentioned lunar ghost towns... i see the very same possibility with asteroid colonies, once ore is depleted, it will be only a small settlement far away from trade routes... possibly they move the whole mining colony to another not too far asteroid, or desert it.

Once depleted, you've got real estate. And why bother moving real estate? There are very advantageous points in the solar system, and few are more advantageous than Earth-Lunar or Earth-Solar libration. Lots of energy, cheap to get to once you're off these godforsaken planets and perfect for staging missions to other interesting places in the Solar System. You move material to these locations, not the other way around.[/quote]

 

[GTOM]

Position asteroids (especially not so small ones) into positions so they can be connected with cables requires lots of delta-V, i think that energy is far enough to land on Mars, and build roads. If we can fly easily across the solar system i think we can somehow solve get out of the gravity well of a planet, even if we can't construct space elevators on smaller planets.
Energy : we can also build a solar panel forest on Phobos and Deimos and radiate energy to the surface.

Otherwise i have nothing against asteroid mines and docks, they can send lots of useful stuff to the planets.

90% indoor, yes i'am working indoor, and stay at home after work on weekdays, but i require regular travels also.

What i have against nukes? If you blow nukes in the vicinity of planets, fallback, otherwise i don't think it is an efficient method of propulsion, also don't think we should trust nukes to private persons (and i think private companies will have their role in space colonization)
Using nukes instead of regular TNT for mining purposes, well i heard they did such things in Sovietunion, but the radioactive waste don't make me calm...

 

[Pete Cortez]

Position asteroids (especially not so small ones) into positions so they can be connected with cables requires lots of delta-V, i think that energy is far enough to land on Mars, and build roads. If we can fly easily across the solar system i think we can somehow solve get out of the gravity well of a planet, even if we can't construct space elevators on smaller planets.

Mars is 4.1 m/s away. There are several NEAs within less than 1 km/s of low Earth orbit. These are Hohmann transfers, btw. You can probably find alternate routes to considerably more destinations. None of these options, however, help you ascent from a planet's surface. Which is why we should avoid being bound to one in the first place.

Energy : we can also build a solar panel forest on Phobos and Deimos and radiate energy to the surface.

You can do the same near Earth, and you have twice as much incident radiation as you do out by Mars.

Otherwise i have nothing against asteroid mines and docks, they can send lots of useful stuff to the planets.

If you're going to use them anyway, then why not live on them?

90% indoor, yes i'am working indoor, and stay at home after work on weekdays, but i require regular travels also.

The point is this problem is secondary. The other point is that there's no comparison between Earth's "outdoors" and that of Mars. The closest--and only crudely so--analogue would be hiking in Antarctica at polar night. If you absolutely need that experience, you're going to have to construct it, and again the choice boils down to first order considerations.

What i have against nukes? If you blow nukes in the vicinity of planets, fallback, otherwise i don't think it is an efficient method of propulsion, also don't think we should trust nukes to private persons (and i think private companies will have their role in space colonization)

So don't trust them to private persons. Set up an agency--the Bureau of Spinning Stuff--and have them use the nukes. Assuming you use nukes for this purpose. And I'm proposing using nukes hundreds of thousands to millions of miles away from planets.

Using nukes instead of regular TNT for mining purposes, well i heard they did such things in Sovietunion, but the radioactive waste don't make me calm...

Unless there's a good reason to atomize good mineral resources, I'm not advocating using nuclear explosives for mining.

 

[GTOM]

Ok, NEAs are near, that is good, they could serve as a good starting point, but the majority of asteroids are in the asteroid belt, farer from Mars, and aerobreak doesn't help. If you can position them into orbits so they can be connected by cables, then construct a martian space elevator is also far from impossible, so climb out from the gravity well will be far easier than now.

"If you're going to use them anyway, then why not live on them?"

Why don't use emptied mines for living on Earth? Of course the mining companies has to produce housing for necessary personnel, but IMHO high standard of living won't be a big concern, those habitats will be rather crammed places, since there is only a belt, that has uniform g-force, expansion is more difficult than on a planet.

Ok, so going out will be only the concern of adventurers, most people don't want to leave the gravity well neither, when they have an entire planet to colonize, explore, visit. So i think, that a number of asteroid mining colonies will send lots of ores to the planets, but the majority of people will choose the planets.

 

[mfb]

Building a martian space elevator (or many of them) is probably way easier than all those large-scale engineering projects discussed here.
Alternatively, the thin atmosphere might allow some direct ground-based launch structure.

If you're going to use them anyway, then why not live on them?

Why live on them? What do you do there once the valuable ressources are extracted and everything has to be imported?

 

[GTOM]

How easy or hard to dig deep into martian soil?
(I speculate about a south pole colony, i read the south pole shows signs of ozone, and has permanent cap of dry ice. )
If a probe or vehicle has strong enough batteries, how much could a sandstorm take away its vision, with all the dust and electricity?

 

[D H]

How easy or hard to dig deep into martian soil?

Trivial. Mars has no "soil". It has regolith.

In most places where humans live, you have dig a rather deep hole through the soil before you hit regolith. Soil on the Earth is chock full of organisms, most of which are very, very small. Humanity is still learning about the extreme importance of those microbes in the soil to the plants that grow in the soil.

 

[GTOM]

http://arstechnica.com/science/2011/04/mars-south-pole-holds-nearly-an-atmospheres-worth-of-co2/
www2.isunet.edu/index.php?option=com_docman&task=doc_download&gid=334

http://www.users.globalnet.co.uk/~mfogg/zubrin.htm

I received the following links about terraformation. I have tried to check obvious crackpottery, but sorry, I'm not qualified enough, i'd like to learn, whether they can be realistic or not, what are the main problems with them? (Provided we have lots of resource for colonization.)

 

[mfb]

There is no example of a thick CO₂ atmosphere to study, so the validity of climate models for that is at best questionable.
The proposed atmosphere is completely toxic for humans, which is certainly a disadvantage. Better than no atmosphere (no pressurized suit necessary, some cosmic ray protection), but the result is not a nice planet where we could walk around without oxygen supply.

 

[GTOM]

How much the atmosphere protects against UV-rays and other harmful radiation? (I know, not enough, but how serious rad protection should be needed?)

 

[newjerseyrunner]

We need machines that are capable of maintaining themselves I think. With advances in AI and robotics, I think the first people to walk on Mars are probably already born, the first people to live there for a lifetime is probably the generation after that.

 

[mfb]

How much the atmosphere protects against UV-rays and other harmful radiation? (I know, not enough, but how serious rad protection should be needed?)

Negligible. Protection against UV is easy, even a glass window is sufficient. Protection against high-energetic radiation needs more shielding.

 

[Generator Gawl]

Trivial. Mars has no "soil". It has regolith.

In most places where humans live, you have dig a rather deep hole through the soil before you hit regolith. Soil on the Earth is chock full of organisms, most of which are very, very small. Humanity is still learning about the extreme importance of those microbes in the soil to the plants that grow in the soil.

I'm not too sure on specifics if Mars has wind or not, but do you think that the regolith is on the surface because of the erosion of its surface soil it had originally? The current surface could have possibly had many meters of top soil on top before its magnetic field shut down and its atmosphere was mostly stripped. Share the info if you have it, I'd appreciate it greatly!

 

[Janus]

I'm not too sure on specifics if Mars has wind or not, but do you think that the regolith is on the surface because of the erosion of its surface soil it had originally? The current surface could have possibly had many meters of top soil on top before its magnetic field shut down and its atmosphere was mostly stripped. Share the info if you have it, I'd appreciate it greatly!

Mars definitely has winds. They can kick up dust storms which, from time to time, cover the whole planet for weeks at a time. Mars was in the middle of the largest one ever recorded in 1971 when Mariner 9 arrived. NASA had to wait a couple of months for it to clear before they could get images of the surface.

 

[GTOM]

What is the average frequency of dust storms?

 

[Generator Gawl]

Mars definitely has winds. They can kick up dust storms which, from time to time, cover the whole planet for weeks at a time. Mars was in the middle of the largest one ever recorded in 1971 when Mariner 9 arrived. NASA had to wait a couple of months for it to clear before they could get images of the surface.

Do you think that is the reason for exposed regolith? Maybe the dust top layer was blown off over the eons, exposing the hard and compact lower layer of rock and then eroding that into the fine dust that we see settling on top. Just off the top of my head.

 

[marcus]

Trivial. Mars has no "soil". It has regolith.

In most places where humans live, you have dig a rather deep hole through the soil before you hit regolith. Soil on the Earth is chock full of organisms, most of which are very, very small. Humanity is still learning about the extreme importance of those microbes in the soil to the plants that grow in the soil.

To help with the definition of terms, so we can be on the same page:
https://en.wikipedia.org/wiki/Regolith
==quote==
Regolith is a layer of loose, heterogeneous superficial material covering solid rock. It includes dust, soil, broken rock, and other related materials and is present on Earth, the Moon, Mars, some asteroids, and other terrestrial planets and moons.
==endquote==

So regolith occurs on Earth and it includes SOIL. Soil is therefore a type of regolith. You do not need to dig a hole to "hit regolith". DUST is also a type of regolith and can be distinct from soil. Let's look up soil and see what is special about the type of regolith called soil. Probably it has to do with the inclusion of organic material. Would volcanic ash, alluvial gravel, or desert sand (especially if extremely dry and nearly free of organic substances) always be considered "soil"? Or would it simply be classified as (a non-soil type of) regolith?
Here's from the Wikipedia "Soil" article:
===quote https://en.wikipedia.org/wiki/Soil ===

A represents soil; B represents laterite, a regolith; C represents saprolite, a less-weathered regolith; the bottom-most layer represents bedrock.
===endquote==
So Earth has layers of non-soil regolith. If you strip off the top layer, remove the soil-type regolith you may find other layers of unconsolidated material which are classified as regolith.

So I would expect there are places on Earth where soil has been removed, which are bare non-soil regolith. Or where because of extreme environment soil has not formed.

 

[marcus]

Do you think that is the reason for exposed regolith? Maybe the dust top layer was blown off over the eons, exposing the hard and compact lower layer of rock and then eroding that into the fine dust that we see settling on top. Just off the top of my head.

A dust layer would qualify as regolith. If it is not covered by some other layer it is exposed. So it would be exposed regolith.
The term was introduced in 1897
==quote https://en.wikipedia.org/wiki/Regolith#Etymology ==
The term regolith combines two Greek words: rhegos (ῥῆγος), "blanket", and lithos (λίθος), "rock". The American geologist George P. Merrill first defined the term in 1897, writing:

"In places this covering is made up of material originating through rock-weathering or plant growth in situ. In other instances it is of fragmental and more or less decomposed matter drifted by wind, water or ice from other sources. This entire mantle of unconsolidated material, whatever its nature or origin, it is proposed to call the regolith.[1]"
==endquote==

== https://en.wikipedia.org/wiki/Regolith#Earth ==
Earth's regolith[2][3][4] includes the following subdivisions and components:

• soil or pedolith
• alluvium and other transported cover, including that transported by aeolian, glacial, marine, and gravity flow processes.
• "saprolith'", generally divided into the
  • upper saprolite: completely oxidised bedrock
  • lower saprolite: chemically reduced partially weathered rocks
  • saprock: fractured bedrock with weathering restricted to fracture margins.
• volcanic ash and lavas...

...
...
==endquote==

 

[GTOM]

What are the true colors of Mars? (Regolith, sky, Sun at top and at sunset)
My problem is, that many photos have false colors, that can be confusing.

 

[mfb]

The surface appears mainly reddish, and the Mars rovers have some realistic images. The sky is more complicated due to the Purkinje effect, see the Wikipedia article about the Martian sky view.

 

[GTOM]

The surface appears mainly reddish, and the Mars rovers have some realistic images. The sky is more complicated due to the Purkinje effect, see the Wikipedia article about the Martian sky view.

Thanks. It is weird to me, how the vicinity of Sun becomes blue? Even if scattering is so weak, how does thick air swallow or scatter more red, when the rusty dust reflects red and swallows blue?

 

[mfb]

If the particles are small enough, they just let blue pass through while red is still scattered (at the level of molecules, not due to the size of the dust).

 

[my2cts]

I do not see why anyone in his right mind would want to live on Mars. Recently I flew over Australia. Lots of emptyness there.

 

[Neon]

I don't see any trouble in warming Mars since we are experts at it. I read nuking Mars at the ice caps to release CO2 methane water .But radiation and radioactive stuff from the nuke is bad.Just it needs a magnetic field is hard.

 

[_PJ_]

Sending probes and unmanned vessels to setup the basis for a hardy plant-life to take hold and photosynthesize some oxygen and generate a nit
rogen cycle, soil and recycle some polar ice, then when it's essentially taken hold after a few millennia, whatever status of mankind may be technologically able to travel there safely to begin a hands-on terraforming.

 

[marcus]

Since we just turned a page, here for continuity are the last three posts.

I do not see why anyone in his right mind would want to live on Mars. Recently I flew over Australia. Lots of emptyness there.

I don't see any trouble in warming Mars since we are experts at it. I read nuking Mars at the ice caps to release CO2 methane water .But radiation and radioactive stuff from the nuke is bad.Just it needs a magnetic field is hard.

Sending probes and unmanned vessels to setup the basis for a hardy plant-life to take hold and photosynthesize some oxygen and generate a nitrogen cycle, soil and recycle some polar ice, then when it's essentially taken hold after a few millennia, whatever status of mankind may be technologically able to travel there safely to begin a hands-on terraforming.

 

[D H]

I don't see any trouble in warming Mars since we are experts at it.

While we collectively may have warmed the Earth a bit (and will continue to do so), we are not "experts" at this. We have accomplished this by pure bungling. That expertise does not carry forward to Mars. We haven't the foggiest idea how to warm Mars.

I read nuking Mars at the ice caps to release CO2 methane water. But radiation and radioactive stuff from the nuke is bad.

That was Bored Elon Musk speaking. It was not a serious proposal. Do the math. Hundreds of Tsar Bomba (the largest bomb ever built) equivalents would have very little effect with regard to releasing CO₂ and H₂O at the Mars ice caps. With regard to methane, there isn't much on Mars.

Releasing all of the CO₂ at Mars' ice caps into Mars atmosphere will not do much to help Mars warm up. Mars' atmosphere is almost entirely CO₂. Increasing that by another 25% won't do much (about a third of Mars' CO₂ is in its ice caps). Think of it this way: We are concerned with a doubling of CO₂ in the Earth's atmosphere from pre-industrial levels. The current consensus is that this will result in a 1.5° to 4.5° increase (Celsius) annual average temperature by the end of this century. A 25% increase in Mars' CO₂ atmospheric content will result in an even smaller increase. Mars needs to get a lot warmer than a mere 1.5° to 4.5° to become habitable.

Just it needs a magnetic field is hard.

Scientists go back and forth on how important a role magnetic field plays in a planet retaining its atmosphere. The current thinking appears to be that it is secondary, at best. Far more important are mass and distance from the Sun. Venus and Titan both have very thick atmospheres, much thicker than the Earth's, but neither has a significant magnetic field. With Venus, it's mass that counts. With Titan, it's distance from the Sun. Mars is too close to the Sun for a planet that small to hold a significant atmosphere for a geologically significant length of time.

Mars doesn't need to hold an atmosphere for a geologically significant length of time to be habitable. It merely needs to hold onto that atmosphere for a humanly significant length of time. A few hundred thousand years is but an instant geologically, but it is an extremely long span of time as far as humans are concerned.

 

[mfb]

Mars doesn't need to hold an atmosphere for a geologically significant length of time to be habitable. It merely needs to hold onto that atmosphere for a humanly significant length of time. A few hundred thousand years is but an instant geologically, but it is an extremely long span of time as far as humans are concerned.

Well, do you want to sublimate all the ice caps if you expect to lose the resulting CO2 to space forever within hundred thousand years?
Okay, chances are good it would be done if it gives some short-term benefit...

We had a link to a study recently, but I don't find it now. Increasing the CO2 in the atmosphere would raise the temperature, which then would help releasing more CO2. A study suggested that the initial amount needed to start that process could be a small fraction of the ice caps, resulting in a different stable state.

 

[DHF]

When Musk proposed nuking Mars, his comments really should have been accompanied by a rimshot.
Nuking the planet to make it habitable is like burning your house down because it is messy.

Even if it somehow made sense, you would need an ungodly amount of money to transport that make warheads to Mars as well as a magic wand to convince the government to let go of that much firepower.