On the plus side (for plants), the Martian atmosphere is about 95% CO2. Even though the total pressure of the atmosphere is much less than our own, the partial pressure of CO2 is still about 20 times higher (erring a bit on the generous side).
On the other hand, Mars is about 1.5 times as far from the sun, so the intensity of sunlight is less than half, and temperatures are correspondingly colder. Then again, if we're going to support human colonists, we probably need a nuclear power source anyway. So let's assume we rig up bright lighting to grow our plants.
There's some uncertainty about the soil, but at least some studies suggest that it could support life. There's probably frozen water there, so we'll use the spare heat from our nuclear reactor to melt some.
Humans need approximately 30g of Oxygen per hour, which is roughly 1 mole. A fast-photosynthesising plant can produce 30 umol/m2/s. Running the numbers, you'd need 9 square metres of leaf area photosynthesising at that rate per person - assuming it could carry on 24 hours a day. To supply food, you'd need rather more, because not all of the carbon fixed goes into edible parts.
This is actually a lot more feasible than I initially thought. You'd probably want to send robots ahead to construct the base and plant the plants, though. And you still have the problem of life support for the journey, which would be several months.
The experiment was a closed biosphere life support system, 36m^2 involving two subjects for 30 days. The article mentions the moon and mars. As I understand it, this thing would be a sealed capsule that you bring with you. This forms part of the ongoing field of CLESS (controlled ecological life support systems). All the references I've seen point to the Russian Bios-3 project as being the first public example of this.
I am also interested to hear more about your ideas regarding the feasibility of martian agriculture :)
If you have a nuclear reactor or extensive solar panels, you may just as well use it to split CO2 into O2 and CO (monoxide gas can also burned as fuel). Plant photosynthesis is rather inefficient if your goal is a breathable atmosphere. If the goal is biomass for food, then just call up Monsanto for a few space-dense crops.
It would probably easier to oversize the powerplant (to generate oxygen, growlights, melt water, treat air and waste) than to try to bring along a whole biological ecosystem. On the first few trips at least...
The advantage with the powerplant approach is that you can live anywhere with rock and ice in the soil (most airless planetoids) or CO2 and water in the atmosphere (Venus, Mars or the gas giants).
Mars is about 1.5 times as far from the sun, so the intensity of sunlight is less than half
Don't break out the nukes yet…
No cloud cover is going to push up the average insolation, plus a thinner atmosphere will absorb less. Dust will bring it back down some amount.
Temperature could be handled with insulation. Aerogel might be good here. A thin layer of glass sufficiently hard to survive the blowing dust and then a layer of aerogel to retain heat but still pass most of the light.
Hmm and RTG like the one Curiosity is using could be used to charge batteries at night and then run growlights during the day. Excess heat could be captured to keep the temperature up. There is a the radiation hazard of course.
A simpler solution is something like that setups that the aquaponics folks run. [1] Basically if you've got electricity (nuclear power) and water (from the soil/ice) you can build pressurized grow room to make food. It would be interesting for these guys to build such a system underground to get an idea of how much external electricity it needed to function.
> So let's assume we rig up bright lighting to grow our plants.
Sorry, but this is missing the point in as big a way as possible if you are using a nuclear plant. Even providing half intensity sunlight for large scale agricultural purposes is not feasible from an economic standpoint. Use the intensity of sunlight that's there. You just have to accept higher acreages and longer growing times. That would still enable civilization.
I wonder what types of plants would be most amenable to growing on Mars. The environment could be simulated in greenhouses (red houses ;) on Earth to cultivate successful plants (genetically-engineered or bred the old fashioned way).
It's odd that any mention of Elon Musk colonizing Mars results in rapturous worship.
Other efforts, China in particular, seem to attract scorn. Especially in light of the fact that Elon Musk's original plan was to send a greenhouse with plants to Mars.
It works like this: Grade school kids running around have puns pop into their heads, so by the time they get to high school, they're over the obvious ones. However this only works for their native language.
This is why translated puns can sound very stupid. It's also why you're likely to sound stupid when you try to pun in Chinese.
Far from. It takes nearly 2 years just to get to Mars.
Also, China tends to be a fast copier, not a leader. They seem to leave the bulk of development costs to someone else. So I think it's unlikely that they will front the resources it'll take to make a Mars mission possible.
I hate to knee-jerk this one, but my first reaction to this is that it's probably propaganda. In the States a few years ago, there was an effort to create a self-contained ecosystem and it failed no matter how hard the engineers behind it tried. That China can suddenly say "Yo guys, we got it to work" out of the blue is suspicious at best.
Not to say they haven't got something half-functional. I'm just very skeptical that it's as great as they say it is.
Since soil samples on mars seem to be strongly oxidizing, even containing perchlorate, the vegetables are likely to catch fire upon touching martian soil.
Mix the soil with fine grained coal and water, and the oxidizing power disappear. The remaining coal can be used as a fertilizer. (I'm not sure if this is the more economical recipe.)
And growing vegetables on the moon is far too expensive to be practical - moon rocks cost thousands of dollars per gram!
EDIT: OK, for the benefit of whoever didn't have a sense of humor, I was suggesting that the astronauts might be planning on bringing some soil with them.
I'm all for this, the current policy of "don't contaminate Mars with organic materials" brings us nowhere, let's put some life on there and see what happens!
I'd be a big fan of sending loads of bacteria with the potential to survive, and some water and stuff, to Mars. Just to see what happens. Hey, the Martian environment would be a "gross evolutionary pressure", right? :)
It's a worthwhile goal but the preparing is a poor choice of words because it sounds like it's happening next week. You prepare yourself for work in the morning. You prepare for going to the supermarket. You prepare to take a dump by making sure toilet paper is present. You prepare for a trip. You research growing plants on Mars for many years and eventually stage operations on the Moon. Finally, when the day comes, you prepare for the first mission to Mars.
But this cannot be of much use, even if they can make an atmosphere somehow, they would need an active core for magnetic field to protect from solar particles/radiation.
Their experiment was using a closed biosphere, so they're bringing the atmosphere with them.
Really, I think the original article was terrible; it omitted important details to make the whole thing sound more silly. Closed biological systems are an interesting field of research.
I'm not sure about radiation levels on a mars mission, but if we can solve the problem for humans, it should be solvable for plants/algae.
My impression was that Curiosity's sensors have shown that the presumed danger of Martian radiation has been greatly overestimated. Unfortunately, I can't remember the sources, but I've read it in multiple places.
The magnetic field on Earth is not what protects you from radiation. It's the thickness of the atmosphere. Lots of radiation is uncharged particles which don't care at all about a magnetic field.
There's a lot of thinking in the comments here which is good for what it is, but which lags far behind engineers and scientists who have thought about it for years.
These are very good news indeed. I started to wonder what good Elon Musk's colonists and tourists will do on Mars upon arrival. And it appears that they shall be able to buy some grocery! Isn't that wonderful?
"During the experiment, four kinds of edible vegetables, namely lettuce, leaf lettuce, gynura bicolor and sonchus oleraceus, were planted in a 36-square-meter area to absorb the carbon dioxide exhaled by the two astronauts and provide them with oxygen and 30-50 grams of fresh vegetables per meal per person."
Google tells me you need 1 ton of soil to cover 30m^2 to a depth of 25cm. So now I'm interested to know if/how they're optimising for mass efficiency.
[+] [-] takluyver|13 years ago|reply
On the plus side (for plants), the Martian atmosphere is about 95% CO2. Even though the total pressure of the atmosphere is much less than our own, the partial pressure of CO2 is still about 20 times higher (erring a bit on the generous side).
On the other hand, Mars is about 1.5 times as far from the sun, so the intensity of sunlight is less than half, and temperatures are correspondingly colder. Then again, if we're going to support human colonists, we probably need a nuclear power source anyway. So let's assume we rig up bright lighting to grow our plants.
There's some uncertainty about the soil, but at least some studies suggest that it could support life. There's probably frozen water there, so we'll use the spare heat from our nuclear reactor to melt some.
Humans need approximately 30g of Oxygen per hour, which is roughly 1 mole. A fast-photosynthesising plant can produce 30 umol/m2/s. Running the numbers, you'd need 9 square metres of leaf area photosynthesising at that rate per person - assuming it could carry on 24 hours a day. To supply food, you'd need rather more, because not all of the carbon fixed goes into edible parts.
This is actually a lot more feasible than I initially thought. You'd probably want to send robots ahead to construct the base and plant the plants, though. And you still have the problem of life support for the journey, which would be several months.
[+] [-] xyzzy123|13 years ago|reply
http://english.peopledaily.com.cn/90786/8044143.html
The experiment was a closed biosphere life support system, 36m^2 involving two subjects for 30 days. The article mentions the moon and mars. As I understand it, this thing would be a sealed capsule that you bring with you. This forms part of the ongoing field of CLESS (controlled ecological life support systems). All the references I've seen point to the Russian Bios-3 project as being the first public example of this.
I am also interested to hear more about your ideas regarding the feasibility of martian agriculture :)
[+] [-] iwwr|13 years ago|reply
It would probably easier to oversize the powerplant (to generate oxygen, growlights, melt water, treat air and waste) than to try to bring along a whole biological ecosystem. On the first few trips at least...
The advantage with the powerplant approach is that you can live anywhere with rock and ice in the soil (most airless planetoids) or CO2 and water in the atmosphere (Venus, Mars or the gas giants).
[+] [-] jws|13 years ago|reply
Don't break out the nukes yet…
No cloud cover is going to push up the average insolation, plus a thinner atmosphere will absorb less. Dust will bring it back down some amount.
Temperature could be handled with insulation. Aerogel might be good here. A thin layer of glass sufficiently hard to survive the blowing dust and then a layer of aerogel to retain heat but still pass most of the light.
[+] [-] ChuckMcM|13 years ago|reply
A simpler solution is something like that setups that the aquaponics folks run. [1] Basically if you've got electricity (nuclear power) and water (from the soil/ice) you can build pressurized grow room to make food. It would be interesting for these guys to build such a system underground to get an idea of how much external electricity it needed to function.
[1] http://en.wikipedia.org/wiki/Aquaponics
[+] [-] stcredzero|13 years ago|reply
Sorry, but this is missing the point in as big a way as possible if you are using a nuclear plant. Even providing half intensity sunlight for large scale agricultural purposes is not feasible from an economic standpoint. Use the intensity of sunlight that's there. You just have to accept higher acreages and longer growing times. That would still enable civilization.
[+] [-] cpeterso|13 years ago|reply
[+] [-] Synthetase|13 years ago|reply
Other efforts, China in particular, seem to attract scorn. Especially in light of the fact that Elon Musk's original plan was to send a greenhouse with plants to Mars.
Perhaps I over-estimate the HN crowd.
[+] [-] skrebbel|13 years ago|reply
Really, I love Chinese humor. It's underrated.
[+] [-] stcredzero|13 years ago|reply
This is why translated puns can sound very stupid. It's also why you're likely to sound stupid when you try to pun in Chinese.
[+] [-] anthonyb|13 years ago|reply
[+] [-] vidarh|13 years ago|reply
[+] [-] qiqing|13 years ago|reply
“It’s the Gobi Desert,” said Wang Yu, the vice director of economic planning. “There’s not much other use for it.”
http://www.nytimes.com/2009/07/03/business/energy-environmen...
[+] [-] TeMPOraL|13 years ago|reply
[+] [-] vitno|13 years ago|reply
Competition from china is the only thing I can see spurring the USA into action.
[+] [-] MichaelApproved|13 years ago|reply
Also, China tends to be a fast copier, not a leader. They seem to leave the bulk of development costs to someone else. So I think it's unlikely that they will front the resources it'll take to make a Mars mission possible.
[+] [-] bitteralmond|13 years ago|reply
Not to say they haven't got something half-functional. I'm just very skeptical that it's as great as they say it is.
[+] [-] pooop|13 years ago|reply
[+] [-] gus_massa|13 years ago|reply
[+] [-] xyzzy123|13 years ago|reply
EDIT: OK, for the benefit of whoever didn't have a sense of humor, I was suggesting that the astronauts might be planning on bringing some soil with them.
[+] [-] quarterto|13 years ago|reply
[+] [-] jeffool|13 years ago|reply
Mind you, I'm not advocating that position, but I certainly expect it.
[+] [-] JonnieCache|13 years ago|reply
Also, you forgot step 4.
[+] [-] ultramundane8|13 years ago|reply
[+] [-] Aardwolf|13 years ago|reply
[+] [-] ommunist|13 years ago|reply
[+] [-] xradionut|13 years ago|reply
[+] [-] Aardwolf|13 years ago|reply
[+] [-] TazeTSchnitzel|13 years ago|reply
[+] [-] tocomment|13 years ago|reply
[+] [-] geuis|13 years ago|reply
[+] [-] polymatter|13 years ago|reply
[+] [-] MrBrandon|13 years ago|reply
[+] [-] Achshar|13 years ago|reply
[+] [-] xyzzy123|13 years ago|reply
Really, I think the original article was terrible; it omitted important details to make the whole thing sound more silly. Closed biological systems are an interesting field of research.
I'm not sure about radiation levels on a mars mission, but if we can solve the problem for humans, it should be solvable for plants/algae.
[+] [-] rpm4321|13 years ago|reply
[+] [-] danielweber|13 years ago|reply
[+] [-] stcredzero|13 years ago|reply
Get your hands on this book and read.
http://amzn.com/0684835509
[+] [-] danielweber|13 years ago|reply
http://www.amzn.com/145160811X
[+] [-] ommunist|13 years ago|reply
[+] [-] jcfrei|13 years ago|reply
[+] [-] xyzzy123|13 years ago|reply
"During the experiment, four kinds of edible vegetables, namely lettuce, leaf lettuce, gynura bicolor and sonchus oleraceus, were planted in a 36-square-meter area to absorb the carbon dioxide exhaled by the two astronauts and provide them with oxygen and 30-50 grams of fresh vegetables per meal per person."
Google tells me you need 1 ton of soil to cover 30m^2 to a depth of 25cm. So now I'm interested to know if/how they're optimising for mass efficiency.
[+] [-] positivelogic|13 years ago|reply
[+] [-] flipchart|13 years ago|reply
[+] [-] flyinRyan|13 years ago|reply
[+] [-] queryly|13 years ago|reply
[+] [-] unknown|13 years ago|reply
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