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Hi, I'm Leigh and this is NASA Now.
The launch of the space shuttle is just a short time away.
During today's program we'll hear from a NASA engineer
who works on the shuttle's guidance, navigation
and flight control systems called G. N. C. And we'll find
out why "Three" is an important number
for calculating the location of the shuttle in space.
But first, let's find out what's happening at NASA Now!
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NASA's newest Earth observing satellite mission is called
Glory and it's scheduled to launch
from Vandenberg Air Force Base in California in February.
Glory's mission will help improve our understanding
of how the sun and tiny particles called
"aerosols" affect earth's climate.
The mission also marks the first satellite launch
under President Obama's Climate Initiative.
When the shuttle mission STS-133 launches
in February it will be headed to the International Space Station
where it will deliver an external platform.
The platform holds large equipment and spare components.
The shuttle will also deliver Robonaut 2 or R2,
the first human-like robot in space.
NOW, let's take a look back at the past!
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April 12th 1981, almost 30 years ago we celebrated the maiden
launch of the first flight of the space shuttle Columbia.
The shuttle orbited the earth 37 times during its mission.
The primary purpose was to check out the overall shuttle system
and have a safe ascent into orbit
and a safe return to earth.
Mission accomplished.
NASA's next shuttle launch is approaching and we're lucky
to have George Hatcher, a GNC Engineer.
G. N. C. stands for Guidance, Navigation and Flight Control.
Let's listen and watch
as Mr. Hatcher explains the technologies used to locate,
guide and steer the shuttle in its flight to
and from the International Space Station.
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My name is George Hatcher, I'm a guidance, navigation
and flight controls engineer.
Navigation is basically; where am I?
Guidance is how do I get to where I want to go?
And flight controls is, how do I change the direction
that I'm pointing as I move through the atmosphere?
Because the shuttle takes off like a rocket
and orbits the Earth like a satellite, and then returns
to Earth through the atmosphere like an aircraft,
we actually have
to use different control devices in different ways.
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One of the ways that it measures its position is
through three different boxes
that we call Inertial Measurement Units.
Inside these boxes, we have three gyroscopes.
They're sophisticated devices
that basically allow the platform inside the box
to maintain orientation even though the vehicle moves
around it.
And we have three accelerometers.
And the reason I'm making this symbol with my hand is
because we put the accelerometers
on individual axes, they're called orthogonal axes,
that mean that they are 90 degrees away from each other.
And then from the moment that we launch,
they start measuring the accelerations
in those three axes.
And then they have the position so they can provide that display
to the astronauts to say, this is the point
where you are in space.
We have sensors that are on the devices
that the astronauts manipulate.
And the sensors provide a signal
to the general-purpose computers, which are kind
of like the brain of the spacecraft.
There are certain things that can cause the solution
that they provide to the general purpose computers
to drift from reality.
One of the ways that we can compensate for that error
and correct it is through what we call Star Trackers.
And these are cameras that are behind heat shields
and when we open those shields up and allow those cameras
to watch the stars there is a database inside the computer
that can match what the camera sees to a known star chart.
Once it matches that it can tell the inertial measurement units,
this is your exact orientation in space.
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When we get to orbit, we still need
to know what point we are above,
in terms of the surface of Earth?
We need to know where the International Space Station is,
if we're going to dock with it?
And how far we are from it?
And how to get there?
When the shuttle is on orbit, they have the ability
to change the role and the pitch,
and the yaw of the vehicle with that rotational hand controller
that they use when they fly it like an aircraft.
They also have what's called translational hand controller
and that makes the Shuttle translate either forward
to back, or side to side, or up and down.
There are close to a hundred electronick boxes
that do specific functions that are associated with GNC
to get it to go where we want it to go.
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Today we learned that Guidance, Navigation
and Flight Control are critical
to the successful operation of the space shuttle.
Here's your chance to use imagination!
You and your classmates are going
to build a space shuttle glider.
To get started, check out the resources and activities
on the NASA Explorer Schools' Virtual Campus.
Well that's it for NASA Now, be sure to tune in next week
when we'll learn about the Glory Satellite
and the important role it will play
in the study of Earth's climate.
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.