On-screen animation shows developing versions of NASA logos erased to reveal the current logo.
On-screen text reads 'v.1.0, v.2.0, v.3.0, v.4.0'.
On-screen animation shows a space shuttle repeatedly launching until it breaks down.
On-screen text reads 'Repeatability'.
NARRATOR:
We often take the things we use every day for granted.
Various shots of televisions, mobile phones, laptops, blenders, and microwave.
NARRATOR:
We use them and we expect them to work. That's because they're tested many, many times before we even see them.
On-screen animation shows two mobile phones with red prohibition symbols, and a third with a green tick.
On-screen text reads 'v. 1.0, v. 2.0, v. 3.0'.
NARRATOR:
Would you ride in a car that had only been tested once? NARRATOR: On-screen animation shows a car breaking down and crashing.
(Explosion)
NARRATOR:
Probably wouldn't work so well.
On-screen animation shows a hand putting bread in a toaster.
NARRATOR:
How about a toaster?
On-screen animation shows burnt toast and flames erupting from the toaster.
NARRATOR:
Not so good either.
Shot of a satellite in space.
NARRATOR:
Now, what about a satellite? The same thing applies.
Various shots of blurred photographs of space.
NARRATOR:
What if we had a telescope that couldn't take pictures?
Shot of a blurred space photograph brought into focus.
NARRATOR:
Luckily, NASA was able to put glasses on Hubble.
On-screen animation of a satellite in space wearing glasses.
NARRATOR:
But it's not always so easy.
Various shots of people working with equipment in labs.
NARRATOR:
That's why engineers do their best to make sure things work right and will keep working for a long time.
On-screen animation shows a space shuttle delivering parts to space to build a space station.
NARRATOR:
And how do you design something that can do the same thing over and over and over again? You test it!
On-screen text reads 'Testing'.
NARRATOR:
Before we start testing, though, we should make sure we know a little bit about our mission.
Shot of the moon in space. NARRATOR: That way, we can figure out what we're testing as well as what we're allowed to do to improve it.
On-screen text reads 'Mission - design and test lunar lander. Needs - lightweight, crash-resistant, can leave moon, fun to drive?, racing stripes?'
Shot of moon in space with arrow labelled 'Landing - here!'
NARRATOR:
These are called 'constraints'.
On-screen text reads 'Constraints'.
NARRATOR:
Constraints help engineers get a good idea of where to start.
Shot of the lunar surface with a clock counting down from three to one.
On-screen text reads 'Lunar lander test 01.'
NARRATOR:
For example, we probably wouldn't want to build a lunar lander out of, let's say, bricks.
On-screen animation shows a vehicle made of bricks landing on the moon with the American flag.
(Heavy thudding)
NARRATOR:
Actually, let's use that example. We need to land humans on the moon.
On-screen graphic shows a group of astronauts linked by an arrow to the moon.
NARRATOR:
We have a design for a lunar lander.
On-screen graphic shows a grey and white metallic space vehicle.
On-screen text reads 'Lander prototype'.
NARRATOR:
And it has to land safely from the same height each time.
On-screen animation shows lunar lander suspended above the moon's surface as a hand measures the distance with a ruler.
NARRATOR:
We also have to be able to reuse it. So let's try it out.
On-screen text reads 'Lunar lander test, N=1. Go!'
On-screen animation shows lunar lander dropping heavily to the surface and falling over.
NARRATOR:
Well, that didn't work. Good thing we're just testing.
On-screen animation shows a hydraulic crane hook lifting the lunar landing off the surface.
NARRATOR:
Let's try it again. But let's think about how we can make it better.
Shot of the lunar lander on the moon's surface.
On-screen text reads 'Revision 01 - ???????'
NARRATOR:
Maybe some legs.
On-screen text reads 'Revision 01 - add legs!'
On-screen text reads 'Lunar lander test, N=2. Go!'
On-screen animation shows lunar lander landing on the surface and falling over.
NARRATOR:
Close, but how can we keep it from tipping over at all?
On-screen text reads 'Revision 02 - rockets!'
NARRATOR:
Maybe some rockets to help guide it down.
On-screen text reads 'Lunar lander test, N=3. Go!'
On-screen animation shows lunar lander landing smoothly on moon's surface.
NARRATOR:
Great. Now, maybe you were wondering what the letter N was doing up in the corner.
On-screen graphic highlights the on-screen text 'N=1'.
NARRATOR:
Put simply, N is a variable.
On-screen text reads 'Variable'.
Various shots of people working with equipment in labs.
NARRATOR:
Scientists and engineers use this variable to represent the number of times we've tested something.
Shot of lunar lander in space.
On-screen text reads 'Version 1, Version 2, Version 3'.
NARRATOR:
In our example, we've tested our design three times. So N = 3.
On-screen text reads 'N=3'.
NARRATOR:
Luckily, we came up with a good solution.
On-screen animation shows lunar lander touching down successfully on the moon, with a green tick.
NARRATOR:
Some designs need to be tested hundreds of times before they work.
Various shots of space shuttle launching.
NARRATOR:
But that's OK. In the end, all this repetition will lead to success. And NASA knows this better than anyone.
On-screen animation shows cogs and wheels creating a logo.
On-screen text reads 'BEST - beginning engineering, science, and technology.'
(Children cheering)
