Survival on Mars: Radiation & Temperature Challenges

[GTOM]

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.

Redirecting a large asteroid means less pollution, although based on the answers, I'm still skeptical.

 

[Loren]

Let's not forget that the soil is also poisonous. It contains perchlorate, which is going to be a jerk to keep out of living habitats.

I guess the sale of Dust Devils will soar on Mars.

 

[GTOM]

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.

I don't doubt what they say, just sounds strange to me, if magnetic field isn't the key, i would think, with 1/3 g and lower radiation, it would be only 3 times more thin as Earth. Could you link something that explain some details?

 

[Supr4]

Let's not forget that the soil is also poisonous. It contains perchlorate, which is going to be a ***** to keep out of living habitats.

I guess the sale of Dust Devils will soar on Mars.

True. I found an article that seems interesting. It suggests a a biochemical approach to reducing the toxicity of the soil.
Here: http://www.space.com/21554-mars-toxic-perchlorate-chemicals.html

In the short(er) term, it'd probably be best to either use cleaning areas in Mars modules for suits and equipment, or have space suits mounted to external/uncontrolled areas of a Martian habitat.Possibly like this? (Credit: NASA - Moonbase Alpha)

 

[Loren]

True. I found an article that seems interesting. It suggests a a biochemical approach to reducing the toxicity of the soil.
Here: http://www.space.com/21554-mars-toxic-perchlorate-chemicals.html

In the short(er) term, it'd probably be best to either use cleaning areas in Mars modules for suits and equipment, or have space suits mounted to external/uncontrolled areas of a Martian habitat.Possibly like this? (Credit: NASA - Moonbase Alpha)

That would be a good idea.

 

[mfb]

I don't doubt what they say, just sounds strange to me, if magnetic field isn't the key, i would think, with 1/3 g and lower radiation, it would be only 3 times more thin as Earth. Could you link something that explain some details?

Why do you expect a linear relationship between g on the surface and atmospheric pressure?

Without solar wind, the key quantity is the average kinetic energy of the molecules (in the upper atmosphere) compared to the energy necessary to escape from the planet. The escape velocity is about 5 km/s for Mars, for Earth it is 11.2 km/s.

Let's take Earth: T=2000 K, E=3/2 kT = 250 meV (the hot temperature is driven by solar radiation).
The necessary energy to escape for Helium is ##\frac{1}{2} m_{He} v^2_{esc} = 2.6 eV = 10.4 * 250 meV.
While it is rare, some helium atoms will get 10 times their average energy (and move upwards), and escape. Over geological timescales, most helium atoms escape.
Elementary nitrogen needs 3.5 times this energy, or ~35 times the average energy. That is really rare. Molecular nitrogen needs even more energy.

=> on Earth, helium escapes, but nitrogen does not (not including effects of solar wind).

 

[GTOM]

Why do you expect a linear relationship between g on the surface and atmospheric pressure?

Without solar wind, the key quantity is the average kinetic energy of the molecules (in the upper atmosphere) compared to the energy necessary to escape from the planet. The escape velocity is about 5 km/s for Mars, for Earth it is 11.2 km/s.

Let's take Earth: T=2000 K, E=3/2 kT = 250 meV (the hot temperature is driven by solar radiation).
The necessary energy to escape for Helium is ##\frac{1}{2} m_{He} v^2_{esc} = 2.6 eV = 10.4 * 250 meV.
While it is rare, some helium atoms will get 10 times their average energy (and move upwards), and escape. Over geological timescales, most helium atoms escape.
Elementary nitrogen needs 3.5 times this energy, or ~35 times the average energy. That is really rare. Molecular nitrogen needs even more energy.

=> on Earth, helium escapes, but nitrogen does not (not including effects of solar wind).

Thanks. Theoretically, could Mars hold a thicker atmosphere, if it were made of heavier molecules? (nitrogen-oxids, ethane for example) Although it were still unbreathable, but less problem of cold, and lack of pressure.

 

[Neon]

Methane would be good i guess.And can perhaps burn it for lost of co2

 

[mfb]

Methane is one of the lightest gases after hydrogen and helium.
Also, everything with hydrogen is problematic because sunlight can break up those molecules, and free hydrogen escapes easily.

CO2 is quite heavy, and still around on Mars.

 

[Dotini]

A deeply pessimistic assessment of manned missions to Mars:
Testimony to congress from John Sommerer, chairman of the Technical Panel of the National Research Council Committee on Human Spaceflight.
http://spaceref.com/news/viewpr.html?pid=47821

 

[nikkkom]

A deeply pessimistic assessment of manned missions to Mars:
Testimony to congress from John Sommerer, chairman of the Technical Panel of the National Research Council Committee on Human Spaceflight.
http://spaceref.com/news/viewpr.html?pid=47821

"The psycho-social limits on a small group of astronauts confined to extremely tight quarters for multiyear periods, without possibility of real- time interaction with family and friends, pose another poorly understood threat to crew safety and mission success."

This guy forgot that we have these things on Earth called "prisons". Nelson Mandela spent some 26 years in prison, IIRC. For most of that time, he didn't know whether he would ever be free again. His sanity survived that.

 

[mfb]

Prisons have way more space, (usually) way more other persons around, and usually allow contact to family and friends.
On the other hand, people rarely go there voluntarily, they don't go there for research, and they are not as busy as astronauts are.

We have experiments on Earth investigating the social and psychological effects a crew to Mars would encounter. Increasing the sample size would be a small fraction of the overall costs of a manned Mars program.

The report seems to be this one, or a variation of it.

 

[nikkkom]

Prisons have way more space

Maybe US prisons do. I assure you, my country's prisons do not.

(usually) way more other persons around

...a number of which are such that you would rather NOT see them around you...

, and usually allow contact to family and friends.

You again base it on US prisons. :D

On the other hand, people rarely go there voluntarily, they don't go there for research, and they are not as busy as astronauts are.

And they do not get to become historically famous people who settled the first ever human colony on another planet.

 

[D H]

"The psycho-social limits on a small group of astronauts confined to extremely tight quarters for multiyear periods, without possibility of real- time interaction with family and friends, pose another poorly understood threat to crew safety and mission success."

This guy forgot that we have these things on Earth called "prisons". Nelson Mandela spent some 26 years in prison, IIRC. For most of that time, he didn't know whether he would ever be free again. His sanity survived that.

What you have done is unacceptable.

You have accused @mfb is being an American and being biased because of that. That is rude and incorrect. All it takes is one look at mfb's profile page. mfb is not an American.

You have claimed that Nelson Mandela's tiny little prison shows that this testimony is wrong. In doing so, you have discounted the immense number of studies by the US, the Soviet Union, Great Britain, and any other country that has submarines that show that people do not behave rationally when isolated for a long duration. The psychological investigations into the people who want to serve on a submarine is quite intrusive and intense.

For every one Nelson Mandela, there are thousands and thousands of prisoners who come out of prison scarred for life. BTW, Nelson Mandela had 2.4 meter by 2.1 meters by 2 meters of living space in prison. That's 10 cubic meters, for one person. The Orion capsule has about 9 cubic meters of living space, and that's supposedly for a crew of six.

Worst of all, you have ignored all of the other things in that testimony that says that sending humans to Mars and back is but a pipe dream.

 

[Chronos]

Spending a long time in cramped quarters is not fun and provokes enduring psychological issues. A mission to Mars would land a menagerie of psychologically impaired people in a hostile. alien environmnet. That is a recipe for disaaster, IMO.

 

[mfb]

Maybe US prisons do.

Who is talking about the US?
The Soyuz is so small, they have a height limit for astronauts. Ever heard of a height limit for prisons?

For the other two things: I said "usually". There are always exceptions.

The Orion capsule has about 9 cubic meters of living space, and that's supposedly for a crew of six.

Well, a manned mission to Mars probably won't happen in a single Orion capsule.

~2.5 kg of food per person and day (lower estimate) gives 7.5 tons of food over the duration of a typical mission (Hohmann orbits, 500 days). 2.1 tons of oxygen are needed unless H2O/CO2 is used to make new oxygen (~1 kW). You do not have to ship the whole food with the crew, but for safety reasons it is probably not a bad idea. I didn't find payload masses for the capsule.

Worst of all, you have ignored all of the other things in that testimony that says that sending humans to Mars and back is but a pipe dream.

Like a mission to Moon? Or trains faster than a human can run? https://en.wikipedia.org/wiki/Clarke's_three_laws]Clarke's[/PLAIN] laws are relevant. History is full of "impossible" statements that were wrong. This does not mean the study has to be wrong - but we certainly should consider that it could be.

 

[nikkkom]

What you have done is unacceptable.

You have accused @mfb is being an American and being biased because of that. That is rude and incorrect. All it takes is one look at mfb's profile page. mfb is not an American.

Are you trying to say that Germany's prisons are significantly worse than US ones? :)

You have claimed that Nelson Mandela's tiny little prison shows that this testimony is wrong.

The testimony is indeed wrong. Read it again:

"The psycho-social limits on a small group of astronauts confined to extremely tight quarters for multiyear periods, without possibility of real- time interaction with family and friends, pose another poorly understood threat to crew safety and mission success."

"Poorly understood threat". This is the part which is wrong. The threat is WELL understood. There is ample literature and scientific papers about prison environment, there are comparative studies of penitentiary systems of different countries, how cramped conditions affect people, what kind of training is needed to overcome it.

As you pointed out, there is also a large volume of data based on military service on submarines.

 

[mfb]

Prisons just don't have the environment a manned mission to Mars would have.

 

[DHF]

Prisons just don't have the environment a manned mission to Mars would have.

Indeed. I do not feel that Prisons make a very good comparison at all. The only aspect that is similar would be isolation. Other then that, the variables are pretty stark. A stay in a prison, regardless of which country hosts it, is going to be a very different experience then going to Mars so comparing the psychological state of a prisoner is not going to give you an accurate picture at all.\

That being said, I do feel that Mental health is certainly a concern but we can't compare it to any environment we have currently. There are a few projects that simulate a Mars mission including the isolation and daily tasks required but again this are not reliable in studying one's mental fitness because at the end of the day each man and woman on those projects knows that they are still on Earth and at any point they can go back to their lives. Its quite a different picture when you know with 100% certainty that you are millions of miles from home and there is absolutely no turning back. Even the astronauts on the ISS know that in an emergency, rescue or evacuation is within reach.

The closest comparison we have is the Apollo missions and they only lasted several days each.

 

[AgentSmith]

Recycling water never results in pure aitch too oh. But on Earth almost all of us drink recycled water every day, with all sorts of stuff in it. There is water ice at least on Mars, so you have water, oxygen, and hydrogen. The atmosphere is mostly c-o-too, so you have carbon to make methane. So you can breath,drink, stay warm, and have power. That will give you a few days of life. Build your base in a natural cave, or cover a habitat with Martian dirt. Develop a bonding agent for Mars dirt(mirt?). Hydroponics for most food.
But why do all this at once? Send a "preparation lander" with robots and 3-D printers to make a lot of stuff for later. Make and store water, oxygen, hydrogen, and nitrogen, and methane. It will be slow, but time doesn't run out. Then bring all the rest with you. . Figure an unmanned resupply periodically. Could you stay forever? Probably not, but why would you need to? Oh, and use an ion-drive ship to get you there faster than the blast-and-coast method.

 

[mfb]

The atmosphere is mostly c-o-too, so you have carbon to make methane.

Producing methane will need more energy than burning it releases. You need solar or nuclear power.

But why do all this at once? Send a "preparation lander" with robots and 3-D printers to make a lot of stuff for later.

I think every plan to go to Mars involves preparation missions.

Oh, and use an ion-drive ship to get you there faster than the blast-and-coast method.

Where do you get the megawatts of power from that you would need to be faster?

 

[nikkkom]

Indeed. I do not feel that Prisons make a very good comparison at all. The only aspect that is similar would be isolation. Other then that, the variables are pretty stark. A stay in a prison, regardless of which country hosts it, is going to be a very different experience then going to Mars so comparing the psychological state of a prisoner is not going to give you an accurate picture at all.

Sure, it is different in many ways. But there are similarities. You are confined in small space, you can't leave. (Unlike experiments and ISS, where you _can_ leave, prisoners, especially in some more awful countries than Western ones, truly won't be released from their cell, sometimes even in medical emergencies). So it's inaccurate to claim that confinement in small spaces is a completely new, unexplored area of psychology. This is my point, and nothing more. I'm not saying that prisons are perfect training environment for Mars missions.

 

[AgentSmith]

Producing methane will need more energy than burning it releases. You need solar or nuclear power.I think every plan to go to Mars involves preparation missions.Where do you get the megawatts of power from that you would need to be faster?

Methane would be for short-term local use, like powering vehicles. (Not every plan to land on Mars has involved prep missions, but most). The best plan I've seen to date has at least five vehicles and three separate landings on Mars. An ion-drive would not have higher thrust, but constant thrust. That way you have some constant low gravity, while velocity builds up.

 

[mfb]

For a given delta-v capability, constant thrust is worse than a short but high initial thrust. Ion thrusters are limited in thrust so they need to operate for months, but they can achieve a higher delta-v if you have enough time. Which is exactly what you do not want to have on manned missions.
The acceleration from ion thrusters is tiny, astronauts wouldn't notice it with current performances.

 

[thetexan]

One meter of lead? Does that mean the protection from the Earth's atmosphere is the equivalent to one meter of lead? How can that be?

 

[CalcNerd]

Can I jump in? What if we ask for volunteers from an able bodied pool of 60+ year old candidates? As any persons muscles will likely atrophy under reduced gravity, these astronauts only need keep themselves in fair shape for the trip out (Martian gravity isn't as great as Earth either). They take an ecosystem with them, but limited to a 8-15 year plan. They make the trip, a several year stay (some may not return or perhaps, just stay!). Anyone who comes back will need to live out their lives in low Earth orbit. People that do not intend to return to Earth will consume far less calories to maintain their physical conditioning (which could also be detrimental to anyone younger).
.
Cold? Heartless? But exploration has never been kind. I suspect you would receive a large amount of qualified volunteers.
.
Cancer risk may increase with age, but radiation has a cumulative effect and these individuals would already have an approximate life of 15 years vs 30-40. Hence lead shielding could be reduced. Every pound saved is more for food, fuel and even extra space, all VERY valuable for a long term mission (life of this crew, anyway).

 

[nikkkom]

One meter of lead? Does that mean the protection from the Earth's atmosphere is the equivalent to one meter of lead? How can that be?

1 atm pressure is roughly 1kg/cm^2. This pressure is equivalent to 10 meters under water. Water density is 1, lead density is 11.34, so, yes, it's roughly one meter of lead.

 

[nikkkom]

Can I jump in? What if we ask for volunteers from an able bodied pool of 60+ year old candidates? As any persons muscles will likely atrophy under reduced gravity, these astronauts only need keep themselves in fair shape for the trip out (Martian gravity isn't as great as Earth either). They take an ecosystem with them, but limited to a 8-15 year plan. They make the trip, a several year stay (some may not return or perhaps, just stay!). Anyone who comes back will need to live out their lives in low Earth orbit. People that do not intend to return to Earth will consume far less calories to maintain their physical conditioning (which could also be detrimental to anyone younger).

If we (the West) are still free countries, this should be possible, and no one can prohibit people from embarking on an one-way trip.

 

[ogg]

"no one can prohibit people from embarking..." is factually WRONG. This thread, and I've not read all of it, suffers from several logical problems. The first is that it assumes a (very large) number of unavailable technologies are available (or will be). No one (who cares about the truth, which means not counting Mars One fans) claims that the technologies to: 1. Get us to Mars 2. Allow us to survive on Mars for extended (multi-year) stays and 3. Get anyone back, even EXIST. They do not. It is likely that extensions of current technology would allow us to get there (with serious safety risks and costs). It is also likely that extensions of current technology could keep a SMALL number of people supplied for an indefinite perior (at enormous cost). We do not know how to get there safely. We do not know where we could establish a habitat safely. And we don't have even a guesstimate on the order of magnitude of the cost of getting anyone back. We do NOT have the technology for fusion power, ion drives, establishing eco-systems on Mars, or establishing a rudimentary manufacturing base on Mars. This thread qualifies, imho, for the "Not Even Wrong" prize, since it makes so many assumptions about some magical and nebulous future technology. I'd suggest that the best country for sending a mission to Mars would be a brutal dictatorship. All that needs to be done is make the astronauts an offer they can't refuse. Maybe China or North Korea or even Iran (for Allah). Back to my first point. Please think before you post. A rocket (of significant size) is, by definition, a issue which involves national security. Let's talk about "no one can prohibit people from" having a rocket-launcher, bazooka, or surface-to-surface missle...sigh...BTW, for those with a serious interest in manned missions to Mars (in 30 or 50 years) check out the article written by Do, et. al from MIT on Mars One feasibility (2014).

 

[nikkkom]

ogg. Can you stop phrasing your posts in such an aggressive way?

 

[nikkkom]

This thread, and I've not read all of it, suffers from several logical problems.

People having opinions which you aren't agreeing with are not "problems". For one, consider a possibility that sometimes, *you* may be wrong, not them.

No one (who cares about the truth, which means not counting Mars One fans) claims that the technologies to: 1. Get us to Mars

I think the proven chemical propulsion tech can get people to Mars. Yes, today we don't have a LV large enough to do that efficiently, but we know how to build one. The *technology* exists.

2. Allow us to survive on Mars for extended (multi-year) stays and 3. Get anyone back, even EXIST. They do not.

I think you are correct here.

It is likely that extensions of current technology would allow us to get there (with serious safety risks and costs). It is also likely that extensions of current technology could keep a SMALL number of people supplied for an indefinite perior (at enormous cost). We do not know how to get there safely. We do not know where we could establish a habitat safely.

This depends on your definition of "safely". You can't safely go from your home to the nearest shop, there is non-zero risk you can die doing that.

Lets talk about "no one can prohibit people from" having a rocket-launcher, bazooka, or surface-to-surface missle...sigh...

Yes, Elon Musk does not exist...

 

[mfb]

The first is that it assumes a (very large) number of unavailable technologies are available (or will be).

I don't see anyone assuming this. It is often assumed that this technology can be developed. That is the whole point of research: to get something at the end that you did not have before.
We didn't have the technology to build a space station before the first space station was developed, and we did not have the technology to go to Moon before the Apollo program developed that technology. Of course (!) we do not have the technology to go to Mars before a dedicated program establishes this technology. If we would have everything ready to go to Mars and back (or even stay there), this thread would not exist.

We do NOT have the technology for [...] ion drives

We have operational ion drives. Not of the scale you could use them for a manned spacecraft , but again - that is an engineering challenge (or just use chemical rockets).

I'd suggest that the best country for sending a mission to Mars would be a brutal dictatorship. All that needs to be done is make the astronauts an offer they can't refuse.

Finding volunteers is certainly not the bottleneck.

 

[GTOM]

About the psychological problems, well, somehow a russian astronaut could withstand more than one year on Mir.

 

[mfb]

More than one, but they had much more space, a shorter mission duration, more other astronauts around, better communication with Earth, and a quick escape option in case something went wrong.

 

[1oldman2]

If anyone doubts the ability to overcome tech/development issues they should look at the Apollo missions before saying "it can't be done".