How does the space station never run out of oxygen - Alvaro Romero-Calvo and Theo St Francis
video description
Date: 2026-07-10
Related videos
Comments and reviews: 20
always_L3arning
I'm curious if there's a practical way to mount cyanobacteria (blue-green algae) photobioreactors (PBRs) on the outer shell of the ISS.
Consider for a moment: large, algae saturated water silos with a helical scrapers within the unit that acts similar to a cement mixer. Only that the scrapers are fixed in place and the transparent silos rotate slowly around the axis.
Such silos could be powered by solar panels (free energy when exposed to sunlight) and a gas exchange system that pumps in carbon dioxide and extracts oxygen. The scrapers would act like squeegees; clearing the compacted algae from the inner walls and allowing the continuous regeneration of algal blooms as the silo pivots, exposing freshly scraped surfaces to the sunlight.
Something similar to the Offshore Membrane Enclosures for Growing Algae (OMEGA) system, the spirulina can be a form of protein for the astronauts which would help clear excess algal build-up from the system.
A series of cylindrical shafts could be mounted to the external body of the ISS, with solar panel fins, so that regardless of which side of the ISS is facing the sun, the algal farming system can optimize its chances.
Similar system could also be used for extraterrestrial missions to terraform viable bases; providing a protein-rich food source for people and livestock while creating oxygen in exchange for carbon dioxide and sunlight
reply
I'm curious if there's a practical way to mount cyanobacteria (blue-green algae) photobioreactors (PBRs) on the outer shell of the ISS.
Consider for a moment: large, algae saturated water silos with a helical scrapers within the unit that acts similar to a cement mixer. Only that the scrapers are fixed in place and the transparent silos rotate slowly around the axis.
Such silos could be powered by solar panels (free energy when exposed to sunlight) and a gas exchange system that pumps in carbon dioxide and extracts oxygen. The scrapers would act like squeegees; clearing the compacted algae from the inner walls and allowing the continuous regeneration of algal blooms as the silo pivots, exposing freshly scraped surfaces to the sunlight.
Something similar to the Offshore Membrane Enclosures for Growing Algae (OMEGA) system, the spirulina can be a form of protein for the astronauts which would help clear excess algal build-up from the system.
A series of cylindrical shafts could be mounted to the external body of the ISS, with solar panel fins, so that regardless of which side of the ISS is facing the sun, the algal farming system can optimize its chances.
Similar system could also be used for extraterrestrial missions to terraform viable bases; providing a protein-rich food source for people and livestock while creating oxygen in exchange for carbon dioxide and sunlight
reply
man08839
This world often feels like a badly broken simulation, where the same suffering keeps repeating in different forms. If that's the reality we live in, then before bringing another soul into it, we should first ask ourselves what kind of world we are inviting them into.
Creating life is not only giving someone a chance to experience happiness. It also means exposing them to pain, loss, fear, and suffering. Awareness should come before desire.
reply
This world often feels like a badly broken simulation, where the same suffering keeps repeating in different forms. If that's the reality we live in, then before bringing another soul into it, we should first ask ourselves what kind of world we are inviting them into.
Creating life is not only giving someone a chance to experience happiness. It also means exposing them to pain, loss, fear, and suffering. Awareness should come before desire.
reply
misslotalotus1500
I don't think most people realize how important air is when we talk about space travel. When we watch science fiction or space fiction movies, we usually wonder why it hasn't happened yet, why haven't we reached Mars or other galaxies It turns out there's so much to think about. while we live on this planet that provides everything for us, we tend to always complain and hurt the planet. we're like spoiled passengers.
reply
I don't think most people realize how important air is when we talk about space travel. When we watch science fiction or space fiction movies, we usually wonder why it hasn't happened yet, why haven't we reached Mars or other galaxies It turns out there's so much to think about. while we live on this planet that provides everything for us, we tend to always complain and hurt the planet. we're like spoiled passengers.
reply
brad9189
So I wonder in the electrolysis process used on the ISS, how much of the mass of a liter of water is left after some of it is broken down into oxygen and hydrogen How much water do they regularly lose over time How much oxygen can you get from a liter of water this way It seems like it must be fairly efficient, or they would need to constantly send more water to the station.
reply
So I wonder in the electrolysis process used on the ISS, how much of the mass of a liter of water is left after some of it is broken down into oxygen and hydrogen How much water do they regularly lose over time How much oxygen can you get from a liter of water this way It seems like it must be fairly efficient, or they would need to constantly send more water to the station.
reply
TheAlmostEffectYT
The engineering is impressive, but what stood out to me is the mindset behind it.
In space, you don't build systems that work only when conditions are ideal, you build systems that keep working when failure isn't an option.
That's a principle worth applying far beyond engineering
reply
The engineering is impressive, but what stood out to me is the mindset behind it.
In space, you don't build systems that work only when conditions are ideal, you build systems that keep working when failure isn't an option.
That's a principle worth applying far beyond engineering
reply
ted_ed
I’m at the beginning of the video and I’m not a chemist. But I know people breathe in O2 and breathe out CO2. So it seems to me if you could filter the CO2 and remove the carbon then you’d have pure oxygen to breathe. I have no idea how you’d do that though.
reply
I’m at the beginning of the video and I’m not a chemist. But I know people breathe in O2 and breathe out CO2. So it seems to me if you could filter the CO2 and remove the carbon then you’d have pure oxygen to breathe. I have no idea how you’d do that though.
reply
rphb00
Dude we are not going to Mars. Not until we have a Moon base and a rotating space station.
And seriously. why don't we just use plants. Big rotating space wheel filled with plants and water, the rotation means that plants know which way to go.
reply
Dude we are not going to Mars. Not until we have a Moon base and a rotating space station.
And seriously. why don't we just use plants. Big rotating space wheel filled with plants and water, the rotation means that plants know which way to go.
reply
timofejSE
I don't get it. Ok, it's expensive to carry oxygen onboard. A bright idea - let's carry water that we can convert to oxygen instead! I was completely sure that they just regenerated O2 from CO2, so that the circle is closed.
reply
I don't get it. Ok, it's expensive to carry oxygen onboard. A bright idea - let's carry water that we can convert to oxygen instead! I was completely sure that they just regenerated O2 from CO2, so that the circle is closed.
reply
onenote6619
It has to be said that if you designed a Space Station with any real possibility of running out of Oxygen, that would be an epic failure and should be answered with a firing squad made up of all your engineering teachers.
reply
It has to be said that if you designed a Space Station with any real possibility of running out of Oxygen, that would be an epic failure and should be answered with a firing squad made up of all your engineering teachers.
reply
Sjalabais
I had heard about MOGA, but never seen such a consistent explanation before. What's most worrisome about the old process is that it's not a closed loop. One might even expel waste into space. That's unelegant.
reply
I had heard about MOGA, but never seen such a consistent explanation before. What's most worrisome about the old process is that it's not a closed loop. One might even expel waste into space. That's unelegant.
reply
ed273. 17
It never occurred to me that bubbles won't separate from liquid without gravity. These engineers had to really think outside the box! You wouldn't be able to test for that in the lab on earth.
reply
It never occurred to me that bubbles won't separate from liquid without gravity. These engineers had to really think outside the box! You wouldn't be able to test for that in the lab on earth.
reply
jessicatymczak5852
They need to develop a CO2 recycling system. With energy, they would synthesize a sugar from the CO2, which could then be fed into a bioreactor to make other organic molecules.
reply
They need to develop a CO2 recycling system. With energy, they would synthesize a sugar from the CO2, which could then be fed into a bioreactor to make other organic molecules.
reply
tuna. tunaaaa
I do not understand that, if we keep taking water and releasing hydrogen into space, will the water eventually be depleted or we have some way to maintain the amount of water
reply
I do not understand that, if we keep taking water and releasing hydrogen into space, will the water eventually be depleted or we have some way to maintain the amount of water
reply
ted_ed
Fantastic as usual! I've written a short review on Kuriositas and embedded the video there. I had never even considered this question, but am glad I stayed to find out the answer!
reply
Fantastic as usual! I've written a short review on Kuriositas and embedded the video there. I had never even considered this question, but am glad I stayed to find out the answer!
reply
containedhurricane
Imagine what humanity could achieve scientifically if most of them didn't waste their time praying to an imaginary god and kill others for some ancient fairy tales
reply
Imagine what humanity could achieve scientifically if most of them didn't waste their time praying to an imaginary god and kill others for some ancient fairy tales
reply
maxfax208
You can create oxygen with algae. I'm pretty sure most of the oxygen on earth is created with algae and plankton not trees. You can bring algae to create oxygen in space
reply
You can create oxygen with algae. I'm pretty sure most of the oxygen on earth is created with algae and plankton not trees. You can bring algae to create oxygen in space
reply
Bradyboy3211
0: 05 Why does your astronaut have the proportions of Slender Man With arms like those, he could reach down to earth and pull an oxygen tank up to the ISS himself.
reply
0: 05 Why does your astronaut have the proportions of Slender Man With arms like those, he could reach down to earth and pull an oxygen tank up to the ISS himself.
reply
deloeste33
As always, an interesting topic explained in an engaging and entertaining way.
But the music was really loud; it pulled me out of the enjoyment and annoyed me.
reply
As always, an interesting topic explained in an engaging and entertaining way.
But the music was really loud; it pulled me out of the enjoyment and annoyed me.
reply
xPUPPETEERx14x
I had to watch this twice. The first time to appreciate the visuals, and the second time to take in the science! I love how funky and human this art style is.
reply
I had to watch this twice. The first time to appreciate the visuals, and the second time to take in the science! I love how funky and human this art style is.
reply
tony_1776
Question, is TED-Ed not an American platform I don’t understand why this video is in the metric system. I don’t understand any of these measurements.
reply
Question, is TED-Ed not an American platform I don’t understand why this video is in the metric system. I don’t understand any of these measurements.
reply
Add a review, comment
Other channel videos
