It’s amazing how complicated just the O2 cycle is. Basically, we don’t yet how to do it without a whole planet being involved.
Like, plants do release O2 sometimes, but they also use O2 as fuel when they grow. Growing a plant requires light. On the earth that’s easy, just put it in the sun. On Mars there’s no atmosphere and no magnetic field, so if you just put a plant on the surface they’ll die. So, you need to grow them underground in a mostly earth-like atmosphere at mostly earth-like pressure lit by artificial lights.
So, you plant a lot of plants deep underground lit by bright artificial lights. Then you need to supply the plants with a lot of water. Some of that water will be released into the air, but some of it will be incorporated into the plant’s body. There’s a whole water cycle that isn’t yet fully understood.
What about the soil? On earth worms and other bugs break down leaf litter and other things into usable soil and bees pollinate many of the plants. So, do you ship up a bunch of bugs? You’d have to supply a whole ecosystem of them so they live in balance. You could go with hydroponics instead, but then you’d need a constant supply of nutrients for the plants, and given the amount of plant matter needed for just one human, that would be a huge supply of nutrients.
I’d love to see another honest, scientifically rigorous attempt at a biosphere project. Building a closed ecosystem on Earth is easy-mode compared to doing it anywhere else, but so far all the Biospheres have been failures. IMO until we can easily do it on Earth, we’re nowhere near ready to do it in space, on the moon, or on another planet.
asking with no experience in this field, what about those 50+ year old glass jars with worms and plants and stuff in them? Do those not count for some reason?
You’d also need to deploy the system, or find a way to maintain it all the way from Earth orbit to Mars’ surface.
You can use the spaceship as a habitat! That way you don’t need to ship an extra habitat … an advantage of reusable rockets.
As for the ship size, starship has about 1000 m³ volume of living space, so you can have a mini-greenhouse in there for growing some vegetables and salad (since those have to be fresh). You have to bring high-calorie food though or grow it outside, since it consumes more area.
You need that living habitate to survive 6 months in 0g minimum, plus move it planetside without breaking anything.
You could expand the habitate to a larger area later, true, but there’s still like 7 mass cycles that need to be maintained long term, and this system needs to be robust enough to trust a few dozen people to. Otherwise, it’s just an extension of Earth’s biosphere and is dependent on regular resupply.
On Mars there’s no atmosphere and no magnetic field, so if you just put a plant on the surface they’ll die. So, you need to grow them underground in a mostly earth-like atmosphere at mostly earth-like pressure lit by artificial lights.
you can put algae in a plastic bag and grow them in there, so they’re in a pressurized container so there’s enough air pressure in there for them.
i’ve actually been thinking about this exact problem, and you don’t actually need to grow wheat on mars. you only need calories, protein, fats, vitamins, fiber. you can get calories and protein from algae (which you can grow in small plastic tubes/boxes). Spirulina (bacteria type) is a typical candidate for that.
It’s especially protein-rich. Growing it would require less than 1000 m² per person, i think, though i’m not sure.
growing salad for vitamins and fiber takes significantly less area (maximum 50 m² per person) and can be done indoors, wherever you live.
It’s amazing how complicated just the O2 cycle is. Basically, we don’t yet how to do it without a whole planet being involved.
Like, plants do release O2 sometimes, but they also use O2 as fuel when they grow. Growing a plant requires light. On the earth that’s easy, just put it in the sun. On Mars there’s no atmosphere and no magnetic field, so if you just put a plant on the surface they’ll die. So, you need to grow them underground in a mostly earth-like atmosphere at mostly earth-like pressure lit by artificial lights.
So, you plant a lot of plants deep underground lit by bright artificial lights. Then you need to supply the plants with a lot of water. Some of that water will be released into the air, but some of it will be incorporated into the plant’s body. There’s a whole water cycle that isn’t yet fully understood.
What about the soil? On earth worms and other bugs break down leaf litter and other things into usable soil and bees pollinate many of the plants. So, do you ship up a bunch of bugs? You’d have to supply a whole ecosystem of them so they live in balance. You could go with hydroponics instead, but then you’d need a constant supply of nutrients for the plants, and given the amount of plant matter needed for just one human, that would be a huge supply of nutrients.
I’d love to see another honest, scientifically rigorous attempt at a biosphere project. Building a closed ecosystem on Earth is easy-mode compared to doing it anywhere else, but so far all the Biospheres have been failures. IMO until we can easily do it on Earth, we’re nowhere near ready to do it in space, on the moon, or on another planet.
asking with no experience in this field, what about those 50+ year old glass jars with worms and plants and stuff in them? Do those not count for some reason?
They work, but there are no humans inside them.
biologically, humans aren’t that special. if you can reliably sustain insects in an ecosystem, it’s not that big of a jump to feed humans as well.
You need a very big one though, and humans need a more varied diet than soil bugs.
You’d also need to deploy the system, or find a way to maintain it all the way from Earth orbit to Mars’ surface.
You can use the spaceship as a habitat! That way you don’t need to ship an extra habitat … an advantage of reusable rockets.
As for the ship size, starship has about 1000 m³ volume of living space, so you can have a mini-greenhouse in there for growing some vegetables and salad (since those have to be fresh). You have to bring high-calorie food though or grow it outside, since it consumes more area.
You need that living habitate to survive 6 months in 0g minimum, plus move it planetside without breaking anything.
You could expand the habitate to a larger area later, true, but there’s still like 7 mass cycles that need to be maintained long term, and this system needs to be robust enough to trust a few dozen people to. Otherwise, it’s just an extension of Earth’s biosphere and is dependent on regular resupply.
Earth is pretty much just a big one. Jury is still out on our ability to maintain it.
you can put algae in a plastic bag and grow them in there, so they’re in a pressurized container so there’s enough air pressure in there for them.
sth like this: link to post
i’ve actually been thinking about this exact problem, and you don’t actually need to grow wheat on mars. you only need calories, protein, fats, vitamins, fiber. you can get calories and protein from algae (which you can grow in small plastic tubes/boxes). Spirulina (bacteria type) is a typical candidate for that.
It’s especially protein-rich. Growing it would require less than 1000 m² per person, i think, though i’m not sure.
growing salad for vitamins and fiber takes significantly less area (maximum 50 m² per person) and can be done indoors, wherever you live.