1
00:00:00,000 --> 00:00:04,000
So in the heat of the summer, these visors really can makes a difference. 

2
00:00:04,000 --> 00:00:08,000
rustling

3
00:00:08,000 --> 00:00:12,000
And the Webb telescope uses the same

4
00:00:12,000 --> 00:00:16,000
principle to block the heat of the sun and even what bounces off the Earth 

5
00:00:16,000 --> 00:00:20,000
and the moon. And just like my car's visor, the telescope's sunshield

6
00:00:20,000 --> 00:00:24,000
unfolds, but its five layers are a little bit thinner. 

7
00:00:24,000 --> 00:00:28,000
A Tennis Court of 

8
00:00:28,000 --> 00:00:32,000
Carbon

9
00:00:32,000 --> 00:00:36,000
This thin material is called Kapton and it makes the sunshield of NASA's James Webb

10
00:00:36,000 --> 00:00:40,000
Space Telescope. So what is this strange Kapton? 

11
00:00:40,000 --> 00:00:44,000
It's a combination of carbon, nitrogen, oxygen and hydrogen, 

12
00:00:44,000 --> 00:00:48,000
but its primary element is carbon. It is only 

13
00:00:48,000 --> 00:00:52,000
1/1000th of an inch thick, that’s a quarter of the thickness 

14
00:00:52,000 --> 00:00:56,000
of the thinnest hair you can find. The five layers

15
00:00:56,000 --> 00:01:00,000
of this reflective material will keep Webb cool and block the light the Earth 

16
00:01:00,000 --> 00:01:04,000
and Moon and our very bright sun, and each layer is the size

17
00:01:04,000 --> 00:01:08,000
of a tennis-court. The sunshield happens 

18
00:01:08,000 --> 00:01:12,000
happens to be one of the most complicated parts of the telescope. 

19
00:01:12,000 --> 00:01:16,000
And that is because it must be packed like a parachute to fit into the rocket 

20
00:01:16,000 --> 00:01:20,000
and then unfold out into space. 

21
00:01:20,000 --> 00:01:24,000
Let's get a better idea at how good this Kapton is at 

22
00:01:24,000 --> 00:01:28,000
reflecting heat, I asked our resident expert in all things mini 

23
00:01:28,000 --> 00:01:32,000
to make me a 3 layered model of the sunshield using the same Kapton

24
00:01:32,000 --> 00:01:36,000
that's on Webb. And then we put this tiny lightbulb to mimic

25
00:01:36,000 --> 00:01:40,000
to heat source that would be the Sun, Earth or Moon. 

26
00:01:40,000 --> 00:01:44,000
See, you can see that heat reflecting off the bottom layer. 

27
00:01:44,000 --> 00:01:48,000
The Kapton worked so well that none of the heat is detected at the top of the model. 

28
00:01:48,000 --> 00:01:52,000
music

29
00:01:52,000 --> 00:01:56,000
The sunshield is capable of dissipating 

30
00:01:56,000 --> 00:02:00,000
500 degrees Fahrenheit over the 5 layers. 

31
00:02:00,000 --> 00:02:04,000
The heat radiates out from each layers that's why each layer gets a

32
00:02:04,000 --> 00:02:08,000
little smaller from the bottom to the top

33
00:02:08,000 --> 00:02:12,000
NASA actually uses Kapton for most its

34
00:02:12,000 --> 00:02:16,000
It not only shields or contains heat, 

35
00:02:16,000 --> 00:02:20,000
it is electrically conductive. All that

36
00:02:20,000 --> 00:02:24,000
shifting Kapton of the unfolding sunshield it could create static electricity. 

37
00:02:24,000 --> 00:02:28,000
But that charge wont build up on the Kapton and jump to the

38
00:02:28,000 --> 00:02:32,000
observatory's super sensitive electronics. And then

39
00:02:32,000 --> 00:02:36,000
Kapton's stability over a wide range of temperatures is why it is a great choice. 

40
00:02:36,000 --> 00:02:40,000
This modified version called mylar

41
00:02:40,000 --> 00:02:46,420
mylar might even help you, if you get cold! 

42
00:02:46,420 --> 00:02:46,421
music