How Do Astronauts Get Oxygen In Space?

Space is a very different environment from Earth. One of the key environmental differences is that there isn’t any oxygen up in space, whilst there is plenty here on Earth. After all, it’s what keeps us, Earthlings, alive. So how do astronauts survive when they’re rocketed up to live and work for extended periods of time on the space station? Considering astronauts rely on having an oxygen supply so they can continue to breathe normally up in space, it naturally raises questions about where they get it all from. How on Earth, or should I say on the space station, do they get their oxygen supply? Let’s find out!

So, how do astronauts get oxygen in space? Astronauts get oxygen in space via an oxygen supply that is contained in the backpack of their spacesuit. Onboard the space station, oxygen is supplied through a ventilation system onboard. But they get the actual oxygen to supply themselves with through a process called electrolysis. This process involves running an electrical current through a quantity of water so that the hydrogen and oxygen molecules are separated. So the oxygen is extracted from the water and used to supply the space station.

In other words, astronauts take water to space.

And from there, the water is manipulated in ways to extract the oxygen for breathing.

Amazing right?

It certainly is.

But it gets even more interesting, as we shall see in the following few sections.

How Do Astronauts Breathe In Spacesuits?

Astronauts are to breathe in space suits because an oxygen supply is stored in their backpacks. A fan then circulates the oxygen throughout the spacesuit, which finds its way into the helmet through a ventilation system.

The spacesuit is a fundamental piece of equipment used by astronauts. Without it, they won’t be venturing outside of the space station. And that’s not much fun.

It would be like going on holiday but only staying on the plane to look out of the window. You want to get off the plane and go and take a look around wherever you’ve flown to.

Astronauts want to do the same. They want to get off the space station and take a look around space.

Plus, it’s part of their obligation to carry out spacewalks. And without a spacesuit, they’re not going to be able to do this without, well, dying.

Spacesuits protect astronauts from the hostile temperatures and radiation of space, but they also provide astronauts with oxygen to breathe in.

The first thing to know is that a spacesuit is like a mini spacecraft, except it’s in the shape of a human body and can be worn by humans.

It’s not like a scuba diving outfit where the diver has to breathe in oxygen through a tube.

The astronaut is just contained inside this mini spacecraft, and whatever is inside it, the astronaut will be able to breathe in just by doing it normally. 

Yes, that does mean they’ll have to breathe in their own farts if they let one rip, as it will be contained inside the spacesuit.

Now, back to being serious! The oxygen itself is stored in the backpack located on, yes, the back of the spacesuit. 

The backpack also contains other things like pieces of equipment, but it is where the astronaut’s supply of oxygen is kept.

Without the backpack, the astronaut won’t have any oxygen to breathe in when out on a spacewalk.

How does this oxygen get into the spacesuit for the astronaut to breathe in?

Well, in the backpack, a fan circulates oxygen through the spacesuit, and a life support system which removes carbon dioxide astronauts breathe out from the suit.

The helmet of a spacesuit has a ventilation system that then provides a flow of oxygen up into its region to be easily breathed in by the astronaut. 

The flexible parts of a spacesuit, mainly the arms and the legs, are made from 16 layers of material. Each layer performs its own function.

One of the material layers will keep oxygen within the spacesuit so that it is not escaping and deplete the astronaut’s supply.

So oxygen is circulated into the spacesuit via a fan. From here, the astronaut can simply breathe it in.

The carbon dioxide astronauts exhale on an out-breath will then exit the spacesuit via a life support system. 

Of course, the oxygen supply isn’t bottomless.

Their storage unit in the backpack will only be able to contain a certain amount.

So astronauts will be on a time limit and will need to return to stock up on more oxygen. 

How Much Oxygen Do Astronauts Need In Space?

Astronauts need 2.52 kilograms of oxygen per day they are onboard the space station.

There are two types of oxygen supply we are talking about here.

The first is how much oxygen an astronaut needs whilst they are out on a spacewalk.

The second is how much oxygen they need for their entire time on the space station. 

Let’s start by talking about the amount needed for a spacewalk. In the backpack of a spacesuit, there are two tanks. Each tank has the capacity to supply over 800 liters of oxygen. 

When an astronaut is in a spacesuit, they will breathe and consume oxygen at about 50 liters per hour.

So, give or take, each tank will supply an astronaut for over 16 hours at a time.

If you think about it, this is more than enough time for astronauts to complete their spacewalks.

I mean, shifts that exceed 16 hours, never mind 32 are illegal, I’m pretty sure. And those rules still apply up in space.

It’s a smart move to give an astronaut a larger supply of oxygen than they’ll ever need in their spacesuit.

They are operating in the most extraordinarily dangerous situations, so it really is best to be on the safe side and stocked up with as much oxygen as possible.

But breathing isn’t just needed on spacewalks. Astronauts need to be breathing all the time. And they spend the rest of their time, when they’re not out on spacewalks, inside the space station.

So the space station needs a constant supply of oxygen for astronauts to live onboard.

NASA calculates that they need 2.52 kilograms of oxygen per day to cater for their astronauts onboard their space station.

How Much Oxygen Does An Astronaut Have?

An astronaut has 100 percent of 16000 liters of oxygen during a spacewalk.

Who would have thought that you could get more oxygen up in space, where there naturally isn’t any than you can do here on Earth?

As we discussed in the last chapter, an astronaut will take 2 tanks of oxygen out with them on a space walk. Each tank has the capacity to supply over 800 liters of oxygen. 

But how much of a percentage of oxygen do astronauts have access to? Well, the facts are shocking.

Spacesuits are pressurized at 4.3 pounds per square inch of them. But the gas in the suit is 100 percent oxygen as opposed to 20 percent, like what we have on Earth. 

This means that an astronaut in a spacesuit floating up amongst the stars has more oxygen to breathe in than someone here, at sea level…without their own astronaut suit, of course.

What Happens If You Run Out Of Oxygen In Space?

If you run out of oxygen in space, you will experience hypoxia, which is oxygen deficiency, and ultimately die.

Time for things to get a bit dark, just like space.

Losing oxygen in space isn’t like losing oxygen here on Earth. The consequences are much worse.

At first, when the oxygen supply runs out, blood will stop being able to send oxygen to an astronaut’s brain.

After 15 seconds, they’ll pass out because there is no oxygen to help the metabolic process. Without this, the brain shuts down.

Although at this stage, the astronaut is not dead, they will be unable to try and save themselves. Someone else could save them, but they probably have only 90 seconds to do so.

After an astronaut has passed out, for the next few minutes, an astronaut’s body will undergo what is called hypoxia, which is basically oxygen deficiency. 

An astronaut will lose their vision, and their skin will turn blue.

They’ll also convulse, and the layer of dermal tissue just under their skin will swell as the water in their muscles is quickly evaporating. What does that mean? Well, the dying astronaut’s body will enlarge to be twice its normal size.

But it’s not over yet! The astronaut’s blood pressure will drop so low that it’ll start to boil. Not ideal, really, especially for your organs.

After this, there’s no saving the astronaut, sadly. They will pass away…but what a way to go!!! I’d take that over drowning any day of the week!


See! Being an astronaut is not some easy peasy leisurely job. They’re risking their lives up there for us, all in the name of scientific discovery.

God bless our astronauts!

I just hope they’ve got enough oxygen up there.

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