B Survival on Mars: Radiation & Temperature Challenges

[_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.

 

[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".

 

[Bernie G]

... 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...

Realistic talk.

 

[1oldman2]

I suspect you would receive a large amount of qualified volunteers.

Where do I sign up please ?

 

[GTOM]

Interesting.

http://www.reuters.com/article/us-space-mars-climate-idUSKCN0YH29N

I wondered about a few things. Could any lifeform on Earth withstand martian conditions, with minimal care (rad protection, or collect some water)? Could gene engineering help somehow? Would it make sense, that the streets of a colony is covered by lead glass usually, but shuttered during a solar storm, when radiation level peaks?

 

[enorbet]

The problems listed here for a manned Mars mission seem to be of 3 types
1) Getting there safely
2) Once there, surviving long enough and well enough to do good Science (or why go?)
3) Returning.

Getting there safely depends on sub-issues such as the number one issue, the definition of "safely". It seems to me that with the possible exception of radiation protection, most issues are within a decade of resolution. NASA is already backing a number of propulsion systems that can vastly increase safety by simply reducing elapsed time. Electric, Fission and Fusion are in the works and while a practical fusion drive might be achievable within a decade, fission drives with good power to weight ratios have already been built and tested. A finished product has high odds for success given a decade and the money to develop it The biggest problem there is Public Opinion, not an inconsiderable obstacle, but at least possible. Reducing trip time to roughly 90 days makes huge difficulties either diminish substantially or just go away altogether.

Returning is a much greater issue since there exists no infrastructure on Mars for liftoff from Mars and the concept of sending a parallel mission to provide even the lesser amount of capability for Mars gravity adds great, possibly near insurmountable, complexity and cost. Possibly the best solution for this is not planning for return at all or within the foreseeable future. This isn't completely unreasonable since more than 200,000 people applied for Mars One and most of those understood they may not return. More than a few have asked themselves "What if it is certain I will not return?" and they still applied. For reference see

Still even if we say those two are essentially solved, the remaining problem is still extremely daunting. The difficulty of just supplying basic needs (medical, food, shelter and oxygen) are massive obstacles requiring a huge amount of cost and effort to overcome, even if we assume and accept it is basically a "suicide mission". There is little point in going if it is impossible to get a return on investment, beyond the personal one of "immortality in the history books". Additionally, that "immortality" would certainly include considerable negativity associated with a "suicide mission" without a substantial return... more than just historical. Who wants to be remembered as a murderer?

If we don't assume return, then nothing physical can be harvested so that leaves only information, scientific information to be gained. This requires Mars quality space suits, instrumentation, and the expertise to employ them (and good judgment) not to mention habitat. Although it seems the South Pole is likely to have the most readily available water ice, even the means to harvest that is unknown technology especially when one consider the weight of any digging and processing tools. However, a digging tool might be cost effective if it is also used to create safer habitat. I haven't seen many plans that involve underground habitat which seems would provide helpful radiation protection at no transit weight penalty, so possibly there are intrinsic problems there that I haven't considered.

Again even if we consider habitat, water and oxygen solved as above, it still leaves medical (both medicine and training beyond mere First Aid) and food. The average adult consumes 6 pounds of food per day. Multiply that by crew size, likely 3 or 4 (let's use 4) and we get 24 pounds of food per day. Even a piddling month stay means 720 pounds of food just for one month. This is not at all trivial even if we assume we have the means to provide decent nutrition without spoilage, and that is by no means a given.

So the bottom line it seems to me is - Yes It is within the realm of possibility to land 4 people on Mars within a decade but even to do just that and assuming they die within a day or two after "phoning home" with a few man/hours of actual Science as a payoff - just that involves huge commitment that I just don't see happening in that time frame. On one hand everything is easier after the first time but even if the crew are actually willing to die shortly after landing, who is willing to send them there for that little payoff on a guaranteed suicide mission?

My guesstimate is 30-40 years given the current level of commitment to advancing space exploration will make many of current difficulties a LOT better odds. I hate to say that since I probably won't be around to cheer and enjoy the data stream, but we are talking reality, right?

 

[mfb]

but we are talking reality, right?

Then more realism would help.

and while a practical fusion drive might be achievable within a decade

No way. We would need a demo on Earth already to have one flying to Mars in 10 years. A spacecraft -sized fusion reactor? We don't have any device that provides surplus energy. Larger ones (as tested on Earth) are easier to make effective and they still didn't achieve a net surplus yet. ITER should do it, but only in more than 10 years, it won't make electricity out of it, it won't have a closed tritium cycle and it is way too large.

fission drives with good power to weight ratios have already been built and tested.

Fission reactors yes, fission drives no, and even the reactors not on a scale where you could use it for propulsion of a manned spacecraft .

We also don't have a spacecraft that can serve as living habitat for 3 months or more. We don't have a rocket that can lift such a spacecraft to space, and we don't have a rocket stage that can do the trans-mars injection.

Possibly the best solution for this is not planning for return at all or within the foreseeable future.

No space agency will send anyone on a planned suicide mission. If you don't want the astronauts to return, you have to plan to provide food, water and so on for decades. Unless you want to start colonizing, that is way more expensive and requires more cargo than landing a Mars ascent stage on Mars.

This isn't completely unreasonable since more than 200,000 people applied for Mars One and most of those understood they may not return.

And how many of them understand some basic science? And if that number is not small enough already, how many have the required knowledge to survive on Mars?

 

[CalcNerd]

No space agency will send anyone on a planned suicide mission. If you don't want the astronauts to return, you have to plan to provide food, water and so on for decades. Unless you want to start colonizing, that is way more expensive and requires more cargo than landing a Mars ascent stage on Mars.

.
What if you select four astronauts that are in their 60's. And since weight is precious, you plan a 10 -15 year plan without any return plan. Yes, a suicide plan of sorts, but all of the astronauts die from natural causes (and yes, you will provide suicide pills too, can you imagine suffering through cancer, which could happen to someone of any age in a high radiation environment. However, THAT would not be public knowledge.). That is pretty much the only option that gets us to Mars in the next 20-30 years, unless we have a major breakthrough in rocket/booster/lift technologies.

 

[mfb]

And since weight is precious, you plan a 10 -15 year plan without any return plan.

Take the 3 kg per person and day from above, and that crew needs ~45-60 tons of food over 10-15 years. For that mass, you can launch a rocket with the astronauts back to orbit, and another one to Mars orbit for trans-Earth injection.

And that's not even considering that the crew will run into medical problems soon as they get older.

That is pretty much the only option that gets us to Mars in the next 20-30 years, unless we have a major breakthrough in rocket/booster/lift technologies.

While Elon Musk's plans won't happen in that timescale, he might have the technology within 20 years, and quite likely within 30 if nothing goes really wrong. The Falcon 9 first stages have an empty mass of ~25 tons, landing a rocket of that mass on Mars would be sufficient to get astronauts back to Mars orbit. The only major breakthrough is landing huge payloads on a surface and reusing the rocket - the first part has been demonstrated on Earth, the second will probably be demonstrated later this year or on early 2017. After that, it's just about scaling things up, and creating living habitats for a crew.

Radiation damage on the surface can be avoided by putting martian soil on top of the habitats.

 

[Drakkith]

What if you select four astronauts that are in their 60's.

ANY plan to send people on a one-way trip to Mars would be rejected by NASA and probably every single other space agency in the world.

 

[nikkkom]

No space agency will send anyone on a planned suicide mission. If you don't want the astronauts to return, you have to plan to provide food, water and so on for decades. Unless you want to start colonizing, ...

That's exactly what we want. Colonizing. (If you don't want to colonize, why bother with manned space exploration anyway?). And colonists, by definition, do not generally plan to ever return.

 

[Ryan_m_b]

A manned mission is a totally different beast to a research outpost which is a totally different beast to a colony.

A colony is going to need regular shipments of everything, declining as a local economy develops. Problem is the cost of that is likely to be astronomical, even spread out over a long period. You've got to ship thousands of people, countless tonnes of tools and equipment, supplies of food/medicine, stocks of plant and animal life etcetera.