[ Sound Effects ]
Hi, I'm Chris and this is NASA Now for January 11, 2012.
We've all seen these incredible images of astronauts
in their spacesuits floating around in space.
If you're anything like me,
you've wondered how those spacesuits work.
Well today, we are going to learn
about the complicated system that provides vital support
to the astronauts during an extravehicular activity,
also known as a spacewalk.
That's ahead, but first here's what's happening at NASA Now.
[ Sound Effects ]
The crew of Expedition 31
on the International Space Station has a special member
who is an astronaut and science and math teacher.
Fight Engineer Joe Acaba, returns to space
for an extended stay aboard the International Space Station.
Before his current mission,
Joe flew aboard Discovery during the STS-119 mission.
While docked with the ISS, Joe stepped outside the station
to conduct critical spacewalking tasks.
[ Sound Effect ]
Today's modern spacesuit is an amazing piece of equipment
with technology that provides many vital functions.
To help us understand the mechanics
of the portable life support system, or PLSS,
is Antja Chambers who works at the Johnson Space Center.
Hello Antja, perhaps you can tell us about the backpack
that we see on the astronauts when they are doing a spacewalk?
One the key components of the spacesuit that doesn't get
as much attention but is very,
very important is the portable life support system
which is usually the backpack that you see on our astronauts.
What does the PLSS do?
What the portable life support system does is,
basically how the name describes it, it provides life support.
And so, some of the key things that we need is breathing air
and so we provide oxygen to the astronauts.
The main portion
of the spacesuit oxygen gets re-circulated.
The astronauts, like everybody on the ground breathes
out carbon dioxide, it gets back into the PLSS.
What the PLSS does is it scrubs the CO2 out of the oxygen
and re-circulates it into the suit.
So that's one of the primary functions of the PLSS.
It also provides the power to the spacesuit,
usually, via battery power.
Can you tell us about the lights that are on the sides?
You can see kind of these headlights on either side.
The astronauts, sometimes if they're on a dark pass
of the International Space Station, it gets dark, and so,
instead of having like a flashlight that they can hold
in their hands, we typically like to put it
on either side of the helmet.
What else does the PLSS,
or portable life support system, do?
It also powers a lot of the systems
that provides status of the spacesuit.
So the spacesuit is constantly giving down any information
to the ground or mission control in Houston on, hey,
this is what the spacesuit's doing.
This is what pressure it's at.
This is how much breathing air remains or oxygen remains
into the system and so that gives that description.
And so we do need power for all of that.
Are there other functions of the PLSS besides power and oxygen?
The spacesuit it has a layer inside it,
we call it the bladder, and basically,
it's almost like a balloon material,
it's a urethane material.
And this urethane material is, by design,
not supposed to breathe.
It's supposed to keep all of the breathing air,
all the oxygen inside the spacesuit.
But as a result, when the astronauts are working,
it's almost like working out in a rain jacket.
You get very hot very quickly and you start sweating.
We don't want our astronauts to do that and so we ended
up putting a garment
on the astronauts while they're inside the space suit.
And this garment it has about 350 feet of tubing
that is stitched throughout that.
And so, what the PLSS does is provide cold water
through that tubing and that tubing takes all the heat away
from your skin so the astronauts are getting cooled.
What part of the PLSS do you work on?
What I work on specifically with both the EMU
and the advanced spacesuit is a carbon dioxide sensor.
The carbon dioxide sensor measures the amount
of carbon dioxide that is going into the helmet of the astronaut
or going into the main spacesuit portion of the astronaut.
Carbon dioxide is a gas that we breathe out.
Plants like it, humans don't.
And so, it's very important
to put the carbon dioxide sensor kind of upstream of the helmet.
And upstream means it's basically
in the airflow before it reaches the helmet
so that we can know what percentages our astronauts
are breathing.
[ Sound Effect ]
Now that you know about the mechanics of the PLSS,
let's hear firsthand what astronauts have to say
about walking in space.
You and your class can learn all about the challenges
of spacewalks with this unique interactive program.
See if you have the right stuff.
Go to the NASA Explorer Schools' Virtual Campus.
[ Swooshing Sound ]
Well that's it for NASA Now,
be sure to follow us on our Facebook page.
See you then on NASA Now.
[ Sound Effect ]
NASA Now comes to you from the Virtual Campus
at NASA Explorer Schools.