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Hi, I'm Lisa and this week
on NASA Now we'll meet an electrical engineer
who gets a real charge out of studying energy from the Sun.
But before we get to that,
let's find out what else is happening at NASA NOW!
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Scientists at NASA Ames are conducting cutting-edge research
in the development of clean energy technologies.
Their focus is on advancing biofuels, solar,
and wind technologies that will help reduce our nation's
dependence on petroleum-based fossil fuels.
By advancing clean energy technologies, NASA Ames hopes
to help our nation reduce greenhouse gases.
NOW, Let's travel back to the past!
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In 1609 Galileo Galilee pioneered the use
of the telescope and recorded sunspots.
His detailed sketches produced in 1612 revealed
that the Sun was a dynamic force.
These sketches have led astronomers
from around the world to investigate the Sun
and how it affects life on Earth.
People have been harnessing the Sun's power
for a very long time.
Since the late 1800's scientists have known how
to convert the sun's energy into electricity.
Today solar energy has become the prime source of power
for many of NASA's missions;
the most impressive is the International Space Station.
Here to tell us about the mechanics of solar panels
and the amazing recent advancements
in solar technology is NASA electrical engineer
Jeremiah McNatt.
Hi, I'm Jeremiah McNatt and this is the solar cell growth lab
at the NASA Glenn Research Center in Cleveland, Ohio.
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Photovoltaics, or solar cells, are referred
to as a green technology, a renewable energy resource.
And that is because once that cell is made and once
that panel is made it will continue to produce electricity
as long the sun is out without giving off any pollutants.
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So we have a solar cell,
it's a special semiconductor that's designed
to convert sunlight into electricity.
How that happens is the sun's rays come down to Earth
and they are absorbed by that semiconductor;
that's your solar cell.
What happens inside the solar cell is, those photons
from the sun, they come in
and they excite electrons inside the crystal
of the semiconductor.
Those electrons are now free to move.
If they are in the right orientation
and the right electrical structure of your sample,
what you can then do is produce an electric field,
which you can then make use of that electricity.
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A solar panel is a collection of solar cells; strung together
with wires in a way to produce a certain voltage and current
to make a certain amount of power
for whatever application you are going to need it for.
There is a wide variety of solar panels and each one is specific
to the environment that it is going to be placed in.
On Earth, we have things like the garden lights.
Those ones are made to be outside
and withstand snow, rain, heat.
But in space, we don't have those issues
but we have other problems, like radiation
and maybe micro-meteoroids.
So the solar panels need to be designed to withstand that.
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Probably the most well know use of solar panels, in space,
is the International Space Station.
As you can see on this model,
you can see the space station has a series of solar arrays.
These arrays are what powers the station.
They are made up of panels like this;
you can see all the individual cells have been connected
in such a way to produce the proper amount
of power to run the station.
Each one of these cells is around 15 percent efficient.
And at the time the space station was designed
that was state of the art.
We have now made improvements beyond that and have cells
that are around this size.
They are around half the size, but can produce
around the same amount of power because the efficiency is
about twice that of the silicon cell.
Solar cells do not actually store electricity all they do is
generate it.
To store it, you need another place to put it, like a battery.
As for the lifetime of solar panels,
the cells themselves will last almost indefinitely.
But, because of some of the electrical contacts
that they have on there and some of the metals that they have
on there, those are what wear away.
So, about 20 to 25 years is the expected lifespan
of most solar cells and solar panels.
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So here at NASA Glenn, we focus
on the high-efficiency solar cells devices.
We do that with this system here.
Our reactions occur inside this chamber.
We'll take substrates, something like this two-inch wafer,
load them up inside a platform in this chamber;
we then use the remote controls
to transfer them into our system.
We can come over here to the computer
where we will load up a recipe.
The recipe has all of the files
that dictate what semiconductor we are going to be growing,
for how long and under what flows, all the conditions.
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The best advice I can give to somebody who wants
to be an engineer at NASA is to always keep tinkering
with things and finding out how things work.
As a kid, I was always taking things apart and giving them
to my mom and saying, "put them back together for me."
And it was always given back to me as a, "well,
you took it apart; figure out how to put it back together."
I think that is what got me to where I am.
The degrees are great and that is what will get you
in the door, but that passion to know how things operate
and why they work is really what keeps the work exciting.
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Did you know that there was a time when electricity
in the White House was partially produced by solar panels?
In 1977, President Jimmy Carter had an expansive row
of 32 solar panels installed on the West Wing.
The panels were removed in 1986 by President Ronald Regan.
Today plans are in place once again to install solar panels
on the White House by Spring of 2011.
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Today we learned how NASA is making major advancements
in solar technology.
Now it's your turn.
Check out this cool activity found right here
on the NASA Explorer Schools Virtual Campus.
Now you can get into the act and design a podcast
about solar energy or a solar array.
Just go to NASA's Do-It-Yourself website for clips,
tips and information on how to submit your podcast.
Well that's it for NASA NOW, Be sure to join us next week
when we'll see what the crew of Expedition 26 is up to
on board the International Space Station.
We'll see you next time on NASA NOW!
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NASA NOW comes to you from the virtual campus
at NASA Explorer Schools.