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Wonder if this could be done in space? A few months ago I read about the idea of solar energy being captured in space, and I struggled with the question of how

Wonder if this could be done in space? A few months ago I read about the idea of solar energy being captured in space, and I struggled with the question of how to transport that energy to where we'd like to use it. If the algae could grow in space, and this process could occur in space, then we could wastefully convert solar to oil in space, and spacecraft could use that oil in space. Lot of if's and speculation there, but it's an interesting line of thought.

VLM 13y ago
I think you'll find radiation to be an interesting additional challenge to add to the mix. That and the relative lack of local oxygen. I get what you're saying though, its a heck of a lot more rational to design and airdrop an algae plant on Mars than to expect oil wells to produce on Mars.
- ceejayoz 13y ago
  > I think you'll find radiation to be an interesting additional challenge to add to the mix. Not as much in near-Earth orbit where we enjoy much of the Earth's magnetic field's protection. Astronauts come back with an elevated risk of cancer but not tremendously so. > That and the relative lack of local oxygen. Grow some photosynthetic algae too, which'll convert sunlight to oxygen.
  - sp332 13y ago
    I can't tell if you're joking, but photosynthesis rearranges carbon dioxide and water into sugars, releasing some of the oxygen from the water molecules.
    - VLM 13y ago
      And when you burn the algae sourced synthetic kerosene and algae sourced O2 in your rocket engine (or whatever you're doing with it) you'll run out of water. And its dumb to ship unprocessed water up into space if you can use cheap earth based refineries to ship the same weight of highly refined fuel. Keep those heavy refineries at the bottom of the gravity well unless you have a really good reason to hoist them up. So that was the origin of my idea that this isn't going to scale in space "in general". I'm told Europa has a lot of water, other than the whole lack of sunlight thing, I could see Europa as the "fuel tank of the solar system" in the future. Maybe it could be economically viable to mine comets and turn them into fuel while they're near the sun? Or mine icy asteroids? I think you're going to overall have more trouble finding water in space than energy.
hobbes300 13y ago
> I struggled with the question of how to transport that energy to where we'd like to use it Lasers
- johnchristopher 13y ago
  Thus spoke our prophet: Let me tell you one of my pet peeves: space solar power. Okay, the stupidest thing ever. If anyone should like space solar power, it should be me. I got a rocket company and a solar company. I should be really on it, ya know. But it's like, super obviously, not going to work because, ya know, if you have solar panels - first of all, it has to be better than having solar panels on Earth, so then you say, okay, solar panel is on-orbit, you get twice the solar energy - assuming that it is out of Earth's shadow - but you've gotta do a double conversion. You've gotta convert it from photon to electron to photon, back to electron. You've got to make this double conversion, so, okay, what's your conversion efficiency? Hmm. All in, you're going to have a real hard time even getting to 50%. [The solar cells are better.] It does not matter, put that cell on Earth then. See, that's the point I'm making. Take any given solar cell, is it better to have it on Earth, or is it better to have it on orbit? What do you get from being in orbit? You get twice as much sun - best case - but you've got to do a conversion. You've got to convert it the energy to photons - well, you have incoming photons that go to electrons, but you - you've gotta do two conversions that you don't have to do on Earth, which is you've got to turn those electrons into photons and turn those photons back into electrons on the ground, and that double conversion is going to get you back to where you started, basically. So why are you bothering sending them to bloody space. "I wish I could just stab that bloody thing through the heart." BTW - electron to photon converters are not free and nor is sending stuff to space. Then it obviously super doesn't work. Case closed. You'd think. You'd think case closed, but no. I guarantee it's gunna come up another ten times. I mean, for the love of God. From: http://shitelonsays.com/transcript/elon-musk-panel-bta-2012-2013-01-28 http://shitelonsays.com/transcript/elon-musk-panel-bta-2012-...
  - UnFleshedOne 13y ago
    Isn't the point of solar in space, well, space? You get less efficiency, but you are not going to run out of deserts nearly as fast. So the ultimate scale is not limited.
thelambentonion 13y ago
>> how to transport that energy to where we'd like to use it I've always thought that a rectenna[1] would be the most efficient way to send power from orbit down to Earth.
ori_b 13y ago
The problem is that algae is biomass. Thanks to conservation of mass, whatever amount of biomass you bring down from space needs to come from somewhere, and space is famously devoid of mass, let alone anything for algae to consume. That means that the problem of algae farms in space becomes one putting algae food into orbit. I'm not sure how effective launching literally tons of material into space will be.
- scarmig 13y ago
  Tons is an understatement. You're forgetting the one plausible energy source, however: the gravitational energy that the biomass has in outerspace. If you could figure out how to capture the energy of millions of tons of material moving from orbit to the Earth's surface, that might be able to provide the large majority of the energy needed to bring it up there in the first place. I wonder how efficient we could make space elevators.
deleted 13y ago
[deleted]

VLM 13y ago

I think you'll find radiation to be an interesting additional challenge to add to the mix. That and the relative lack of local oxygen. I get what you're saying though, its a heck of a lot more rational to design and airdrop an algae plant on Mars than to expect oil wells to produce on Mars.

ceejayoz 13y ago
> I think you'll find radiation to be an interesting additional challenge to add to the mix. Not as much in near-Earth orbit where we enjoy much of the Earth's magnetic field's protection. Astronauts come back with an elevated risk of cancer but not tremendously so. > That and the relative lack of local oxygen. Grow some photosynthetic algae too, which'll convert sunlight to oxygen.
- sp332 13y ago
  I can't tell if you're joking, but photosynthesis rearranges carbon dioxide and water into sugars, releasing some of the oxygen from the water molecules.
  - VLM 13y ago
    And when you burn the algae sourced synthetic kerosene and algae sourced O2 in your rocket engine (or whatever you're doing with it) you'll run out of water. And its dumb to ship unprocessed water up into space if you can use cheap earth based refineries to ship the same weight of highly refined fuel. Keep those heavy refineries at the bottom of the gravity well unless you have a really good reason to hoist them up. So that was the origin of my idea that this isn't going to scale in space "in general". I'm told Europa has a lot of water, other than the whole lack of sunlight thing, I could see Europa as the "fuel tank of the solar system" in the future. Maybe it could be economically viable to mine comets and turn them into fuel while they're near the sun? Or mine icy asteroids? I think you're going to overall have more trouble finding water in space than energy.

hobbes300 13y ago

> I struggled with the question of how to transport that energy to where we'd like to use it Lasers

johnchristopher 13y ago
Thus spoke our prophet: Let me tell you one of my pet peeves: space solar power. Okay, the stupidest thing ever. If anyone should like space solar power, it should be me. I got a rocket company and a solar company. I should be really on it, ya know. But it's like, super obviously, not going to work because, ya know, if you have solar panels - first of all, it has to be better than having solar panels on Earth, so then you say, okay, solar panel is on-orbit, you get twice the solar energy - assuming that it is out of Earth's shadow - but you've gotta do a double conversion. You've gotta convert it from photon to electron to photon, back to electron. You've got to make this double conversion, so, okay, what's your conversion efficiency? Hmm. All in, you're going to have a real hard time even getting to 50%. [The solar cells are better.] It does not matter, put that cell on Earth then. See, that's the point I'm making. Take any given solar cell, is it better to have it on Earth, or is it better to have it on orbit? What do you get from being in orbit? You get twice as much sun - best case - but you've got to do a conversion. You've got to convert it the energy to photons - well, you have incoming photons that go to electrons, but you - you've gotta do two conversions that you don't have to do on Earth, which is you've got to turn those electrons into photons and turn those photons back into electrons on the ground, and that double conversion is going to get you back to where you started, basically. So why are you bothering sending them to bloody space. "I wish I could just stab that bloody thing through the heart." BTW - electron to photon converters are not free and nor is sending stuff to space. Then it obviously super doesn't work. Case closed. You'd think. You'd think case closed, but no. I guarantee it's gunna come up another ten times. I mean, for the love of God. From: http://shitelonsays.com/transcript/elon-musk-panel-bta-2012-2013-01-28 http://shitelonsays.com/transcript/elon-musk-panel-bta-2012-...
- UnFleshedOne 13y ago
  Isn't the point of solar in space, well, space? You get less efficiency, but you are not going to run out of deserts nearly as fast. So the ultimate scale is not limited.

thelambentonion 13y ago

>> how to transport that energy to where we'd like to use it I've always thought that a rectenna[1] would be the most efficient way to send power from orbit down to Earth.

ori_b 13y ago

The problem is that algae is biomass. Thanks to conservation of mass, whatever amount of biomass you bring down from space needs to come from somewhere, and space is famously devoid of mass, let alone anything for algae to consume. That means that the problem of algae farms in space becomes one putting algae food into orbit. I'm not sure how effective launching literally tons of material into space will be.

scarmig 13y ago
Tons is an understatement. You're forgetting the one plausible energy source, however: the gravitational energy that the biomass has in outerspace. If you could figure out how to capture the energy of millions of tons of material moving from orbit to the Earth's surface, that might be able to provide the large majority of the energy needed to bring it up there in the first place. I wonder how efficient we could make space elevators.

deleted 13y ago

[deleted]