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>> Hey there.
I'm Tom Marshburn,
an astronaut living
and working aboard
the International Space Station,
the sole space-based
proving ground
and stepping stone
for NASA's Artemis Program.
Have you ever wondered
how astronauts up here
get fresh, breathable oxygen?
The answer might surprise you.
Come on, follow me,
and let's check it out.
The oxygen we breathe
comes from recycled water.
The Water Recovery System
recycles waste water
that takes the form of urine,
sweat, and condensation,
and pumps it into
the Oxygen Generator System,
or OGS.
When the water reaches the OGS,
it goes through a process
called electrolysis.
Electrolysis is the process
of creating a chemical reaction
by passing an electric current
through an electrolyte,
which is a solution
containing ions.
This means to decompose water,
an energy source,
like a battery,
is necessary.
We're taking water
and breaking it down
into its two components,
Hydrogen Gas and Oxygen Gas.
The law of Conservation of Mass
states that matter is neither
created nor destroyed
in a chemical reaction.
This means that the number
of atoms in the reactant side
must be equal to
the same number of atoms
on the product side
of the equation.
Notice how, once balanced,
the number of atoms
and their reactants is equal
to the number of atoms
in the products.
The oxygen produced from
this chemical reaction
is vented back to us
in the main cabin
so we can breathe
and continue our work up here.
The hydrogen gas produced
from the chemical reaction
is combined with
the carbon dioxide
we exhale to generate
water and methane.
The methane produced
from this chemical reaction
is vented into space,
and the water feeds
back into the OGS,
completing a regenerative
life support cycle.
So being able to recycle water
is absolutely essential for us
living aboard the space station.
Turns out water is very heavy.
You don't want to have to
carry it up every time
you deliver a crew
to the space station.
So what we do is
we recycle our water,
up to 93% of the water here,
and using the technology
we have now.
To spend a lot of time
in orbit around the moon
and on the lunar surface,
and to go to Mars,
we need to be able to
recycle 98% of the water,
which is what we are doing
right now, investigating
new technologies in order
to be able to accomplish
98% recycle rate.
So in the air right now
around us is, uh, moisture.
It comes off of our bodies.
And that is captured
in the air conditioning systems,
over here to my right,
and to my left.
You can probably hear
the air conditioning system.
And that captures
the moisture coming
from our bodies,
and from some flu--
free fluids we might
have floating around.
That goes to
the water recovery system,
along with our urine,
and then, through a process
of, uh, electrolysis,
we're able to create oxygen.
Not only do we save
on the water,
but we're able to produce
that vital constituent
that's important for--
essential for us to live.
I hope you learned
a little bit more
about chemical reactions
and the law of
Conservation of Mass today.
Now it's your turn to practice
what you've learned,
using the corresponding
classroom connection.
As you can see,
Conservation of Mass
is pretty important on Earth
and in space.
See you next time.