B Survival on Mars: Radiation & Temperature Challenges

[mfb]

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.

Even if you want to colonize in the distant future, you won't start with a colony. You start with a research team exploring the surface and going back, their research results then can be used to plan a long-term manned base, which eventually might become the seed of a colony.

We have a permanent station at the South Pole today. But Amundsen didn't go to the South Pole to stay there: he went there, explored the area, and went back. Later, with better technology and with the earlier research results, we went there again and built a station where people live for months to 1-2 years now. Still not a colony - people always go back after a while.

 

[D H]

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

There's a lot of hype about Mars One. That 200,000 figure is one of them. While 200,000 people indicated some level of interest, only 2000 to 4000 or so actually applied (i.e., they submitted a completed application form and paid an application fee that varied from $5 to $73, based on GDP per capita).

Who wants to be remembered as a murderer?

When people start dying is when they stop the feed from Mars One. It's good to remember that the primary goal of Mars One is to be a reality TV show.

There's another way to be a murderer with respect to Mars. What if there's some kind of life on Mars, and what if microbes carried by the machines we send to Mars kill it? This unknown question is why every vehicle sent to Mars is assembled in a sterile environment and is intentionally opened to vacuum and solar radiation on the trip to Mars. That can't happen if we send humans to Mars. Being remembered as a murderer is one thing. Having our species guilty of planetocide is quite another.

If you don't want to colonize, why bother with manned space exploration anyway?

Colonization is not why we send humans into space. It might be, eventually, but that eventuality is well into the future. We have sent and continue to send humans into space

1. To avoid war. The US and Soviet Union engaged in the race to the Moon because each side severely wanted to beat the other at something grand, and the grandest option of all (global thermonuclear war) was deemed a less preferable option. The International Space Station can cynically be viewed as yet another war avoidance mechanism.
   
2. To showcase humanity at its best. This is a better way to look at the ISS.
3. To learn and do things that might have a return on investment here on Earth. This economic argument is what drove colonization here on Earth. What is the economic benefit of sending a colony to Mars?
4. To learn what is needed to eventually send humans far into space, because we will eventually do so.

There are many other reasons.

To make colonization viable it needs to have some kind of return on investment. That payback might be financial (e.g., asteroid mining, but that too is well into the future), scientific (e.g., telescopes on the far side of the Moon), educational (e.g., the plethora of educational videos created by the astronauts and cosmonauts on the ISS that motivate kids to study science and technology). While a reality TV show about colonists dying on Mars might make for good entertainment for some, it does not qualify as a good reason to send people to Mars.

There are a number of people and organizations who are very concerned about the steadily declining number of people who have been beyond low Earth orbit (the Apollo astronauts are getting old and are a dying breed). The right thing to do in space to rectify this problem is something that pushes the boundaries a bit but is still economically sustainable. Just as the Apollo program was not economically sustainable, so would be sending people to Mars in the near future. Once accomplished, the program would be declared "mission accomplished!" -- and then shut down.

What could be economically sustainable would be to send people back to the Moon / the vicinity of the Moon, only this time to stay for longer than just a few days. This would not cost as much as Apollo did; we now know how to do it. There are a number of advantages of going to the Moon as opposed to Mars. It's cheaper (taxpayers want this). Telescopes on the far side of the Moon (ESA and the Lunar Planetary Institute want this). Bootstrapping asteroid mining (NASA and private space want this). A quick return home in the case of medical problems (astronauts and cosmonauts want this).

 

[WmReed]

Heh getting a straight answer to a simple question on the internet. So hard.

I await the answer myself.

 

[nikkkom]

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

No, you don't have to ship thousands of people. Exactly because of the cost, initial space colony is likely to be even smaller than historical terrestrial colonies. It can be just 4-6 people.

countless tonnes of tools and equipment

Be clever. Send tools to make tools and equipment.

supplies of food/medicine

Medicine yes, food no. Greenhouses, hens. In some 20 years from now, maybe a machine to grow meat tissue (muscles) artificially, instead of hens.

 

[DHF]

I don't think we have to worry about anyone from Mars One dying on camera. It is extremely unlikely that this organisation will ever get anything off the ground. The plans they have proposed and the budget they outlined are not even close to realistic. You don't even need to get into the technical difficulties, the Financial, logistical and political-social obstacles are more then enough to ground the project.

Considering their first launch window is 1.5 years away and they have yet to announce any official contracts to actually build anything yet, I think the very real scenario is that this is a money grab for Mars One.

 

[nikkkom]

There's another way to be a murderer with respect to Mars. What if there's some kind of life on Mars, and what if microbes carried by the machines we send to Mars kill it? This unknown question is why every vehicle sent to Mars is assembled in a sterile environment and is intentionally opened to vacuum and solar radiation on the trip to Mars. That can't happen if we send humans to Mars. Being remembered as a murderer is one thing. Having our species guilty of planetocide is quite another.

I heard this before. Bacteria have no rights. You kill millions every time you brush your teeth. Not landing people on Mars because they might exterminate Martian microbes is ridiculous.

Colonization is not why we send humans into space.

I am not aware of any official ruling why we send people to space. I disagree with your opinion why we do it.

 

[DHF]

No, you don't have to ship thousands of people. Exactly because of the cost, initial space colony is likely to be even smaller than historical terrestrial colonies. It can be just 4-6 people.
Be clever. Send tools to make tools and equipment.
Medicine yes, food no. Greenhouses, hens. In some 20 years from now, maybe a machine to grow meat tissue (muscles) artificially, instead of hens.

The big problem with setting up a colony on Mars is that it *would* take a staggering amount of resources to get it started, there is no real way to shoestring it. The biggest bottleneck is power. Things like building structures and 3D printers to fabricate tools and greenhouses all require power, far more power then a few solar panels can provide and just sending more panels isn't realistic either because panels and the batteries they charge would add mass to the launch and thus cost more. As others have pointed out here, Setting up a colony on Mars would only happen if there was a return on investment.

No Agency or Organisation is going to foot the bill to set up shop on Mars unless we discovered a massive underground deposit of unobtainum there.

 

[mfb]

Mars One was never realistic.

I heard this before. Bacteria have no rights. You kill millions every time you brush your teeth. Not landing people on Mars because they might exterminate Martian microbes is ridiculous.

You kill millions of them, but you don't wipe out the whole species, or even the full tree of life that evolved over billions of years (including us, in the case of Earth), also ruining the opportunity to learn much more about how life evolves.

The NASA rovers actively avoid the regions on Mars where life is the most likely - because they don't want to risk to introduce microbes from Earth there.

Colonization is not why we send humans into space.

I am not aware of any official ruling why we send people to space. I disagree with your opinion why we do it.

Everyone actually sending humans to space agrees with D H and disagrees with you. This will probably change once SpaceX sends humans to space.

 

[Ryan_m_b]

No, you don't have to ship thousands of people. Exactly because of the cost, initial space colony is likely to be even smaller than historical terrestrial colonies. It can be just 4-6 people.

You might start with 4-6 people (in which case you have a research outpost, not a colony) but 4-6 people does not a sustainable technoeconomy make. You will be needing to ship large quantities of people if you want that.

Be clever. Send tools to make tools and equipment.

Obviously! But simply saying "bring tools to build tools" is a far cry from the complex industry a colony would need to be economically self sufficient (or at least sufficient enough that Earth doesn't have to pay through the nose for constant shipments).

Medicine yes, food no. Greenhouses, hens. In some 20 years from now, maybe a machine to grow meat tissue (muscles) artificially, instead of hens.

And all the required technology, tools, material and all the support industries to sustain that closed-agriculture is going to have to come from somewhere and it isn't going to be Matt Damon on his todd with a spanner.

 

[CalcNerd]

Any space mission lasting more than a few years may ultimately be a death sentence to any astronaut thinking to return to earth. Muscles atrophy in space ie the heart too. Mars has less gravity to re-acclimate to, but the Earth after a 5 year absence? Sure, our current astronauts work out, but burning calories for exercise takes food. If you send 60 year old colonists (to placate the people who don't want to send these astronauts on one way missions), you save thousands of pounds as these colonists only have to maintain themselves for Martian gravity.
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If you can't accept the above plan, the first man on Mars will be 50-60 years away. And as the globe gets warmer and these types of projects skyrocket in cost, in 30-40 years you may not see it at all. The humongous amounts of energy to move anything from our orbit to ANY other orbit prohibits anything but a feeble 2 man attempt that is extremely risky for return or just accept the fact that once you touch down on Mars, you are stuck. It isn't the Moon with a low escape velocity.

 

[GTOM]

Just to be sure, i ask here too, how dangerous are the sandstorms?
According to wiki, the winds can start with 400 km/h on the poles, but they also said, that in the thin air, they arent really nasty.

Agriculture, theoretically, could the sun give enough light and heat to a greenhouse, that plants accustomed to cold areas of Earth could grow?

 

[Drakkith]

Just to be sure, i ask here too, how dangerous are the sandstorms?
According to wiki, the winds can start with 400 km/h on the poles, but they also said, that in the thin air, they arent really nasty.

Agriculture, theoretically, could the sun give enough light and heat to a greenhouse, that plants accustomed to cold areas of Earth could grow?

The mean surface pressure is only about 0.6% I believe, so a 400 km/h wind should feel more like 2 or 3 km/h. Particles in the air could pit and erode surfaces still, but you won't get blown over.

Light intensity is about half of that here on Earth, but I don't know how plants would react to the reduced light other than slower growth. I'm sure you could set up some big fresnel lenses or something to increase the amount of light if need be.

 

[mfb]

If you can't accept the above plan, the first man on Mars will be 50-60 years away.

Where is your study showing that a return mission cannot be done quicker - especially as several space agencies disagree with that statement? This is a science forum, not "I'm making up numbers and state them as fact"-forum.

and these types of projects skyrocket in cost

The cost to send stuff to space tends to go down.

The humongous amounts of energy to move anything from our orbit to ANY other orbit prohibits anything but a feeble 2 man attempt

Where is your study showing that?

 

[CalcNerd]

Guilty as charged on 1st and 2nd charge. The third statement about humongous amounts of energy is a FACT. You can crank THOSE numbers out yourself.
.
1st, Mars is NOT the Moon. And until NASA or any other space agency assumes more risk, our current and foreseeable technology doesn't lend itself to getting us to Mars in 2030 or 2040 as the optimistic NASA propaganda implies. I believe NASA relies upon funding from a congress (often by former congressmen such as Newt Gingrich). These guys WANT results, not wasting money on 40-50 year plans (I am being sarcastic here, I actually don't believe there is much intelligence in either house). So if you want funding, do you tell them that, the hard truth? Or do you sell the soft shoe shuffle and put together a nice power point presentation for continued funding. Perhaps NASA will develop a remote lander, such as the Russians did for the Moon, but again, Mars is much more difficult to get off of than the tiny Moon. That may be possible in a decade or so ie 2030. Getting off of Mars and back to good ole Earth is going to take a rocket the size of a Saturn V. I don't envision that in the next 20 years.
.
Physically, Man has a very hard time in space ie see data on our recent astronauts, living in the space station for extended periods of time ie a year or so. A Mars mission will be 3-4 years (ie admittedly with our current rocket technologies). But I don't see anything promising on the horizon to shorten THAT Trip. And if you want to blast your way to Mars with a faster plan, your energy requirements (fuel) go up and your payload goes down. I've heard talk of an Orion project being adapted, but that requires nuclear propulsion that will likely never be approved, at least for a Mars program anyway.
.
You can sell me on Moon bases and all sorts of Moon related ideas. Mars, I'm going to be a skeptic.
.

 

[mfb]

The third statement about humongous amounts of energy is a FACT.

That's is not the critical point. Your claim that this would prevent crew sizes larger than 2 is the unsourced claim. We know rockets can lift crews of 7 to orbit from Earth - with a much higher escape velocity than Mars.
On Mars you need a bigger rocket than the Apollo ascent stage, sure. So what? We didn't discuss costs so far.

I believe

Science doesn't work based on beliefs.
There are also independent reviews of NASA plans.

Getting off of Mars and back to good ole Earth is going to take a rocket the size of a Saturn V.

The SLS, currently in development, is planned to get bigger than the Saturn V. You can also do in-orbit docking with two launches if you need a factor 2 in mass.

 

[enorbet]

Then more realism would help.

I think you and many others "missed the gist". Did you not notice how many REALLY liberal "givens" there were? My point actually was that even if we assume some real show-stoppers can be overcome in 10 years, the basics of food and shelter currently and for a lot longer than 10 years bring it all to a screeching halt. I really hate having to come to such a negative conclusion but that's where the data leads me.

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.

The fusion propulsion in 10 years is admittedly one of my really liberal givens, partly justified I think in that it is not the only improvement on chemical propulsion upon which we are working with no theoretical "no can do" yet.

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 .

Here I beg to differ if only slightly unless I am interpreting the confirmed results with too much fervor.

[qupte=wikipedia-NERVA]
NERVA XE
The second NERVA engine, the NERVA XE, was designed to come as close as possible to a complete flight system, even to the point of using a flight-design turbopump. Components that would not affect system performance were allowed to be selected from what was available at Jackass Flats, Nevada to save money and time, and a radiation shield was added to protect external components. The engine was reoriented to fire downward into a reduced-pressure compartment to partially simulate firing in a vacuum.

The NERVA NRX/EST engine test objectives now included:

1. Demonstrating engine system operational feasibility
2. Showing that no enabling technology issues remained as a barrier to flight engine development.
3. Demonstrating completely automatic engine startup.

The objectives also included testing the use of the new facility at Jackass Flats for flight engine qualification and acceptance. Total run time was 115 minutes, including 28 starts. NASA and SNPO felt that the test "confirmed that a nuclear rocket engine was suitable for space flight application and was able to operate at a specific impulse twice that of chemical rocket system [sic]."[1] The engine was deemed adequate for Mars missions being planned by NASA. The facility was also deemed adequate for flight qualification and acceptance of rocket engines from the two contractors.
[/quote]

Note: Bold within the quote is mine.

So is your argument that even if we really were willing to put the money into it, 10 years is still too short a time to go from NERVA XE to a working mars-ready engine? Considering how much didn't even remotely exist when JFK issued the "Moon Landing Imperative", even given the order of magnitude difference in problems due to distance, in't this commitment like most commitments that "if you wait till you can afford it, you'll never do it" ?

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.

Could you outline the problems that are show-stoppers for a 3 month habitat craft in 10 years? With the reduced exposure time to radiation I think this could be doable in 10 years, again, given the funding. If NERVA NRX/EST 202 is a possibility the 2nd issue is doable. The 3rd issue of mars-injection is a considerably "stickier wicket". So that could be the end of discussion right there, at least for a 10 year time frame.

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.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?

This is the deal-breaker I am talking about - Food and Shelter since despite the number willing to go and die there and even IF some few were actually qualified, nobody is going to plan a suicide mission in any sort of serious proposal and we simply do not have the means now and for a very long time to house and feed a long term stay and shuttling supplies is a huge increase in cost and risk.

FWIW - Colonization? No way! I can't see an actually serious attempt at colonization for anything under 100 years, maybe more. The bottom line is that it is just too expensive to achieve all the breakthrough technology needed for colonization in 100 years, or a manned mission in 10. I wish it weren't so but then "if wishes were Ferrarris..." While a few may be within reasonable reach, the ones that are not, and there are several, are just beyond budget AND foreseeable technology within any timeframe under 20 years, just for a manned visit-and-return mission.

PS Please forgive my lapse of recall on quoting wikipedia protocol. I will attempt to rectify that within 24 hours. Hopefully it isn't too confusing as is even if improvement is rather needed. I should have been asleep hours ago. For now I will "bold" the quote commands.

 

[mfb]

I said fission drives have never been used (in space). A ground test puts it at TRL 5 or 6 depending on how the test worked. It might be possible to build one in 10 years, but that would need significant effort, and putting a lot of fissionable material in space is problematic in terms of politics.

Could you outline the problems that are show-stoppers for a 3 month habitat craft in 10 years?

That part is probably not so challenging (we have ISS modules as prototypes), but it adds to the costs.

If NERVA NRX/EST 202 is a possibility the 2nd issue is doable.

NERVA with the specifications from the Wikipedia page could not launch itself from the ground - 180 tons mass full, but only 35 tons*g thrust. We don't have a rocket that can lift 180 tons. The heaviest existing one gets 23 tons to low Earth orbit, that is not even sufficient for the empty NERVA reactor at 34 tons. Four Falcon Heavy launches might work.

 

[Ryan_m_b]

NERVA with the specifications from the Wikipedia page could not launch itself from the ground - 180 tons mass full, but only 35 tons*g thrust. We don't have a rocket that can lift 180 tons. The heaviest existing one gets 23 tons to low Earth orbit, that is not even sufficient for the empty NERVA reactor at 34 tons. Four Falcon Heavy launches might work.

Would I be right in thinking that those four flights would also add to complexity given that the reactor/rocket would have to then be assembled in space? If a nuclear rocket can't be easily designed in a modular way and instead needs proper assembly that would seem to massively add to the cost by requiring more tools, specialists, possibly infrastructure and time.

 

[nikkkom]

You might start with 4-6 people (in which case you have a research outpost, not a colony) but 4-6 people does not a sustainable technoeconomy make. You will be needing to ship large quantities of people if you want that.

A colony does not start completely self-sufficient.

Colony differs from research outpost by having a different goal. A research outpost focuses on science (and scientists don't plan to stay there forever, they plan to go back), colony focuses on establishing a new place to live, on increasing its self-sufficiency.

simply saying "bring tools to build tools" is a far cry from the complex industry a colony would need to be economically self sufficient (or at least sufficient enough that Earth doesn't have to pay through the nose for constant shipments).

Let's see what a colony need to survive, and what of those items must be shipped from Earth.

Oxygen? Mars has it.
Water? Check.
Power? Solar works. If more is desired, a small nuclear power reactor needs to be shipped once in some 50 years, not every year. Technology exists (submarine reactors).
Food? Can be produced locally, although much research is needed, and initially (while R&D is ongoing) it has to be shipped from Earth. Likely dehydrated.

Tools? 3D printers must be shipped from Earth, initial compliments of machining tools too must be shipped from Earth. Likely a miniaturised (as much as possible, still heavy) steelmaking plant. And/or aluminium plant. And/or rock processing plant (basalt fibers, bricks, etc).
When that is operational, a lot of heavy equipment (for example, earthmoving equipment) can be made locally. Same for construction materials.

Medicine? Must be shipped from Earth, but it's not very massive.

Batteries? Computers, radios, cameras, other semiconductor-based devices? Must be shipped from Earth.

So yes, a significant resupply will have to be sustained. But the most massive and continuous needs such as air, water, food, and basic construction materials don't need to be sent. All heavy items need to be sent only occasionally (reactor, aluminium plant,...), they are not consumables.

A "stupid" approach of just sending everything in ready-made form, including food and construction materials, is clearly not workable. If this thing wants to be a colony, it needs to work towards being a colony. Not a research outpost.

 

[nikkkom]

FWIW - Colonization? No way! I can't see an actually serious attempt at colonization for anything under 100 years, maybe more. The bottom line is that it is just too expensive to achieve all the breakthrough technology needed for colonization in 100 years

Can you list all the breakthrough technology we need to build a Mars colony, and don't yet have?

 

[GTOM]

Can you list all the breakthrough technology we need to build a Mars colony, and don't yet have?

Well i think a nuclear propelled ship wouldn't hurt.
I wondered, could it serve as an orbital power plant, and beam down power to recharge batteries?

 

[nikkkom]

Well i think a nuclear propelled ship wouldn't hurt.

"Wouldn't hurt" is not the same as "must have". Do we "must have" a nuclear propelled ship? I don't think so.

 

[GTOM]

Let's see what a colony need to survive, and what of those items must be shipped from Earth.

Oxygen? Mars has it.
Water? Check.
Power? Solar works. If more is desired, a small nuclear power reactor needs to be shipped once in some 50 years, not every year. Technology exists (submarine reactors).
Food? Can be produced locally, although much research is needed, and initially (while R&D is ongoing) it has to be shipped from Earth. Likely dehydrated.

How much water can be acquired outside the poles? If we have to land on the poles, i think we need to start with nuclear power, so with a nuclear propelled ship.

 

[nikkkom]

How much water can be acquired outside the poles?

People on forum.nasaspaceflight.com discuss all Mars colonization-related topics a lot. Including this one. There was a post where it was estimated water on Mars can even be extracted in sufficient quantities from atmospheric water vapor.

This needs processing of a lot of air, OTOH it eliminates the need to dig the icy regolith and shovel it around. The latter probably can't be done without humans constantly controlling the process.

 

[nikkkom]

Here are links to some discussions on NSF:

http://forum.nasaspaceflight.com/index.php?board=21.0
"Missions To Mars" subforum

http://forum.nasaspaceflight.com/index.php?topic=40178.0
The Mars settlement / Martian homesteading narrative 2 (Read 19865 times)

http://forum.nasaspaceflight.com/index.php?topic=40521.0
Offworld egg production: an analysis (Read 2910 times)

http://forum.nasaspaceflight.com/index.php?topic=40308.0
Water, Methane, and Oxygen ISRU on Mars (Read 1532 times)

http://forum.nasaspaceflight.com/index.php?topic=40555.0
Radiation mitigation strategies for early SpaceX Mars missions (Read 8812 times)

http://forum.nasaspaceflight.com/index.php?topic=40485.0
James Logan, MD. living on Mars. Opinions on his conclusions. (Read 8888 times)

http://forum.nasaspaceflight.com/index.php?topic=40496.0
When you can land anywhere on Mars where’s the best place? (Read 4229 times)

http://forum.nasaspaceflight.com/index.php?topic=40508.0
Interplanetary commerce - Earth<=>Mars if SpaceX succeeds (Read 3179 times)

http://forum.nasaspaceflight.com/index.php?topic=35877.0
Scaling Agriculture on Mars (Read 57504 times)

 

[mfb]

Would I be right in thinking that those four flights would also add to complexity given that the reactor/rocket would have to then be assembled in space? If a nuclear rocket can't be easily designed in a modular way and instead needs proper assembly that would seem to massively add to the cost by requiring more tools, specialists, possibly infrastructure and time.

Based on the Wikipedia numbers, Falcon Heavy could lift the whole reactor up in one piece, with the three additional flights just delivering hydrogen. As far as I know pumping liquid hydrogen from one place to another hasn't been done in space so far, but it does not look like the most complicated procedure. It is certainly easier than assembling a nuclear reactor in space.

Well i think a nuclear propelled ship wouldn't hurt.
I wondered, could it serve as an orbital power plant, and beam down power to recharge batteries?

Possibly, but where is the point? Having the nuclear reactor on the ground gives a much better efficiency (cooling!), better transmission, and you don't need large antennas for power beaming. You have to bring it down which costs some mass, but you get much more energy.

 

[enorbet]

Can you list all the breakthrough technology we need to build a Mars colony, and don't yet have?

Unless I'm mistaken the bulk of the Science done on Mars for the past 20 odd years has not been robotics discovering what is available and possible to sustain a human presence, but rather "instead of", a substitution. Almost everything I see here and elsewhere as proposals for solutions are almost entirely speculation. Example - while there may be several ways to get water and oxygen on mars, we really don't yet know what will work with a net gain, or even at an affordable loss. Such fundamentals must be on a "business as usual" basis if one is to stake one's life, and possibly the health of the whole endeavor for a time, on it.

Another example - since radiation is apparently a severe obstacle is it smarter to bring habitat or dig one underground? We don't even yet know how difficult or what machinery is adequate for digging deep enough, or even in what ground it would be stable enough (juxtaposed?) to create sufficient volume or what lining may be both necessary and sufficient to even be properly airtight. Plus, just what is the Earth equivalent for Radon pollution on mars?... and these are things we know of only because they exist on Earth. We know very little, so far, about what will actually be a "show-stopper" for a human colony on mars.

Bringing habitat seems very likely impractical in that size requirements and resulting payload weight seem prohibitive. Don't underestimate size requirements since, unlike earth, storing machinery outside, exposed to dust is an invitation for disaster.

Energy production should be an obvious problem since we haven't enjoyed such a "breakthrough" here on Earth where cooling towers, batteries, etc are not an issue.

Don't get me wrong. I'm not trying to be a killjoy or say we shouldn't go. I'm just saying we have many years of fundamental work to put in first if we can expect any reasonable odds of success.

 

[1oldman2]

exposed to dust is an invitation for disaster.

True, the issue of Perchlorate needs to be studied in depth.

 

[nikkkom]

Unless I'm mistaken the bulk of the Science done on Mars for the past 20 odd years has not been robotics discovering what is available and possible to sustain a human presence, but rather "instead of", a substitution. Almost everything I see here and elsewhere as proposals for solutions are almost entirely speculation. Example - while there may be several ways to get water and oxygen on mars, we really don't yet know what will work with a net gain, or even at an affordable loss.

Oxygen is a piece of cake. It can be produced from CO2 (reverse water gas shift reaction + water splitting, for example).

Overall, I agree with you. Too little is done to actually investigate and build prototypes for all necessary equipment for a permanent base.

 

[1oldman2]

I found this to be somewhat on topic...
http://www.scientificamerican.com/a...ns-will-settle-mars-and-nowhere-else-excerpt/

 

[D H]

Oxygen is a piece of cake. It can be produced from CO2 (reverse water gas shift reaction + water splitting, for example).

No, it is not. It is at best TRL (technology readiness level) 6, more likely TRL 4 or 5. The one way we do know how to produce oxygen at TRL 9 involves plants. That of course brings up yet another issue, which is that growing plants on Mars is at best TRL 4 or 5.

This exemplifies the key problem with this thread, and elsewhere. While science fiction is easy (Captain Picard: "Make it so!"), engineering is hard, expletively deleted hard. There are boatloads upon boatloads of technologies that are "a piece of cake" from the perspective of science fiction but that are <expletive deleted> hard from the perspective of engineering. Boatloads of these "piece of cake" technologies never make it beyond the TRL 4, 5, or 6 because they in fact are anything but a "piece of cake". This wall where science fiction conflicts with reality is why NASA and the Department of Defense created the concept of technology readiness levels.

 

[rootone]

... the concept of technology readiness levels.

Had not heard of this before, seems eminently sensible.

 

[nikkkom]

> Oxygen is a piece of cake. It can be produced from CO2 (reverse water gas shift reaction + water splitting, for example).

No, it is not. It is at best TRL (technology readiness level) 6, more likely TRL 4 or 5. The one way we do know how to produce oxygen at TRL 9 involves plants. That of course brings up yet another issue, which is that growing plants on Mars is at best TRL 4 or 5.

Unfortunately, almost everything Mars-base-related is at about TRL 5 ("Component and/or breadboard validation in relevant environment") at best. Not even NASA builds and tests (for example) an oxygen-generating chemical plant in simulated Mars environment (which would be 0.008 bar Carbon dioxide 95.9% Argon 1.9% Nitrogen 1.9% Oxygen 0.15% Carbon monoxide 0.05% input, purely electric power supply, closed cycle long-term operation).

However, the chemistry involved is not only well known, it is used (for other purposes) on Earth on a large scale. I stand by my point that _as Mars base preparations go_, O2 production on Mars is not a problem.

 

[mfb]

It is probably easier than various other challenges. However, consider that the ISS still doesn't have a closed gas cycle. Water is recycled, CO2 -> O2 is not done, although it could save payload.

 

[1oldman2]

This is not only relevant, its a good example of what becomes of one "wanting to understand why"
http://www.nasa.gov/feature/scientists-innovation-began-with-wanting-to-understand-why

 

[GTOM]

About producing oxygen, could the peroxides of the ground help?
I heard that an early probe could produce oxygen with pour warm soup onto it.

 

[D H]

The recent posts on Mercury have been moved to https://www.physicsforums.com/threads/colonizing-mercury.878108/ .

 

[1oldman2]

This is going to have a huge effect on manned spaceflight in the future.
From, http://www.nature.com/articles/srep29901
From, http://www.nbcnews.com/health/heart...used-heart-problems-apollo-astronauts-n618116
"We've probably underestimated the impact of deep-space radiation on not
just cardiovascular disease but health in general", said lead author of the
study, exercise physiologist Dr. Michael Delp of Florida State University.

The Apollo astronauts-the first men to land on the moon took a giant
leap for mankind. But the deep space radiation that dosed the men who left
the Earth's orbit may have damaged their hearts, according to a new study
published Thursday in the journal Science.

 

[mfb]

Seriously? No.

In total, 24 astronauts went to the moon, three of them twice. Blindly using the ~10% CVD mortality for non-flight and LEO astronauts, we expect 2.4 of them to die from CVD - but most of them are still alive. 8 of the 24 died so far, we expect 0.8 deaths among them. 43% of 8 are 3.44. No, not significant.

Can it get worse? Yes of course, you can make the moon group even smaller and pick tiny control groups. Their moon group just has 7 astronauts (all male), the LEO group just 35 (including 5 women), the non-spaceflight astronauts just 42 (5 women). Edgar Mitchell (went to the moon) died recently, I guess that's the reason the moon group has just 7 people.
43% of 7 astronauts are 3, with expected 0.7 if we take the other astronauts as comparison. Oh come on. Yes technically it gives p<0.05, but with such a small sample size you can find everything.

That is not bad enough? Let's look at more details:

The study did not check CVD exlusively. They studied "(CVD), cancer, accidents and all other causes of death". Let's ignore the last group, that gives at least 12 different places to look:
- CVD, cancer, accidents
- fraction who died already compared to sample size, or compared to the number of people who died
- is the rate different for all astronauts in space vs. is it higher for Apollo astronauts only

They find a p<0.05 effect when looking at 12 different places? Surprise, surprise.

 

[1oldman2]

Seriously? No.

Well it is possible that I have cited the latest "doom and gloom" study,
I'm curious to see if NASA mentions it, on the bright side I did learn that Scott Kelly grew two inches while on his one year mission.

 

[Fervent Freyja]

This is going to have a huge effect on manned spaceflight in the future.
From, http://www.nature.com/articles/srep29901
From, http://www.nbcnews.com/health/heart...used-heart-problems-apollo-astronauts-n618116

Massive budget cuts for space exploration must be underway...

You never know, the study could be politically motivated. I sure wouldn't want something published that give the public further reason to holler more budget cuts- one little news article published on a trend site is all they really need.

 

[mfb]

I don't think news about radiation effects on humans in outer space would influence the NASA budget so significantly. The SLS/Orion concept is aimed at those missions, but not exclusively.

@1oldman2: I can't comment on the medical part of the animal studies done on Earth, maybe those have some relevance. Anyway, the more I read the worse it gets:

Deaths due to heart failure, myocardial infarction, stroke, brain aneurysm, or blood clots were classified as CVD.

Oh great, even more subgroups to pick from. I guess a single blood cloth death in the Apollo group would already give "significance".

The significance of differences in cause-specific deaths between groups was assessed with Fisher’s exact probability test. Due to this test being considered extremely conservative, a value of P ≤ 0.10 was considered statistically significant.

What? Now we are at 32 groups and they consider P ≤ 0.10 significant? I would be surprised if they found nothing!

 

[1oldman2]

with such a small sample size

This is the fatal flaw in all studies, I watch for that and take it into account. It will be interesting to watch studies like this evolve and learn just how much the figures change as the sample pool grows. (by the way thanks for the statistical perspective on the study, that helps me understand the results much better.)

 

[1oldman2]

You never know, the study could be politically motivated. I sure wouldn't want something published that give the public further reason to holler more budget cuts- one little news article published on a trend site is all they really need.

I like to take the "okay what's the agenda" approach when reading news of any kind. The political aspect of a study can't be ignored in the age of "I got mine". One thing seems pretty certain, the study raised enough legitimate points to warrant more studies, (the government loves to study studies). We are sure to hear more on this, it would be a shame having to launch more materials for rad shielding than equipment and supplies on a trip to Mars.

 

[mfb]

Unfortunately the sample size won't grow much soon. We have the remaining 16 people who went to moon - 45 years ago. Astronauts today tend to be a bit older than the Apollo astronauts, but they are rarely old. More astronauts leaving low Earth orbit again in ~2025 means we get more equivalent data in 2055-2065. Unless there is some serious issue, then we get data sooner.

 

[D H]

Can it get worse?

Much worse. Astronauts are not average, and they are not perfect. They own Corvettes (or even hotter cars) in much higher numbers than average, they race motorcycles in much higher numbers than average, they philander in much higher numbers than average, ... That's what astronauts do. They work very, very hard, and when they're not working they play very hard. While insanely intelligent, they also are willing to take somewhat insane risks. As a result they tend to die rather young. Studies need to factor in NASA's (and also Roscosmos's) selectivity from the very tip of the Bell curve.Full disclosure: My baby is a "little red Corvette", vintage 2002 (Z06). The first owner was a top engineer at NASA who unfortunately developed Alzheimer's. The second owner was (briefly) the *top* engineer at NASA JSC, but his wife said "sell this car, or divorce me!" I'm the third owner. Knock on wood.

 

[mfb]

They compared Apollo astronauts to other astronauts. You could still argue for some selection effect there, but it is not as bad as comparing them to the general population (which they also included as group, but not as main comparison for their study).

 

[Dotini]

Cardiovascular disease (Photo: Michael Delp)

Exposure to cosmic radiation—specifically, charged high-energy protons—causes permanent tissue damage to DNA molecules, effectively shutting down the body’s ability to repair itself. Previous studies have also shown the increasing risks of cardiovascular disease from exposure to low-energy radiation like x-rays or gamma rays.

It’s important to note that according to the Review of NASA’s Longitudinal Study of Astronaut Health by the Institute of Medicine, astronauts have a significantly higher quality of life. Their incomes are relatively high, they are physically fit, and they have lifetime access to premium medical care. These factors should give them a substantially lower chance of cardiovascular-related illness compared to the similarly-aged general population. For the lunar astronauts, it didn’t, and it’s because of the unique environmental conditions they experienced.
http://observer.com/2016/07/space-radiation-devastated-the-lives-of-apollo-astronauts/

 

[mfb]

For the lunar astronauts, it didn’t, and it’s because of the unique environmental conditions they experienced.

That conclusion is just nonsense, given the small sample size they have and the large number of causes of death they studied.

 

[Dotini]

That conclusion is just nonsense, given the small sample size they have and the large number of causes of death they studied.

IMHO wrong to say "just nonsense". I could go with "unproven". At a minimum it is "interesting" and maybe even "important".