1
00:00:00,000 --> 00:00:03,381
[LIVELY MUSIC]

2
00:00:03,381 --> 00:00:13,060


3
00:00:13,060 --> 00:00:16,390
Because the Webb telescope is
too large to fit into a rocket,

4
00:00:16,390 --> 00:00:18,310
engineers have
designed it to unfold

5
00:00:18,310 --> 00:00:20,440
in a kind of
origami like fashion

6
00:00:20,440 --> 00:00:22,000
when it gets into orbit.

7
00:00:22,000 --> 00:00:25,180
That goes for the mirrors
on the Observatory too,

8
00:00:25,180 --> 00:00:28,210
the primary mirror that
collects light from the cosmos.

9
00:00:28,210 --> 00:00:31,210
Well, that light then bounces
up to the secondary mirror

10
00:00:31,210 --> 00:00:33,610
before making its
way to other mirrors

11
00:00:33,610 --> 00:00:36,790
and eventually ending
up into the cameras.

12
00:00:36,790 --> 00:00:38,740
We're here at NASA's
Goddard Space Flight

13
00:00:38,740 --> 00:00:41,290
Center in Greenbelt, Maryland
because the deployment

14
00:00:41,290 --> 00:00:43,660
of the secondary mirror
is about to happen.

15
00:00:43,660 --> 00:00:46,660
So, Adam, how do you guys
get the secondary mirror

16
00:00:46,660 --> 00:00:47,830
into position?

17
00:00:47,830 --> 00:00:52,480
Well, we deploy three struts
that are much like a tripod.

18
00:00:52,480 --> 00:00:57,400
And the secondary mirror
will sit above the backplane.

19
00:00:57,400 --> 00:00:59,860
So how important is this test?

20
00:00:59,860 --> 00:01:01,300
Well, this will
be the first time

21
00:01:01,300 --> 00:01:04,269
that we are deploying the
tripod with a secondary mirror

22
00:01:04,269 --> 00:01:04,989
installed.

23
00:01:04,989 --> 00:01:06,850
As with anything
on this project,

24
00:01:06,850 --> 00:01:08,950
every test builds upon another.

25
00:01:08,950 --> 00:01:12,460
So we want to be able
to master this test

26
00:01:12,460 --> 00:01:14,770
and be able to
perform it again when

27
00:01:14,770 --> 00:01:16,870
we get to the flight hardware.

28
00:01:16,870 --> 00:01:19,900
Well, can we take a closer look
at what's going on down there?

29
00:01:19,900 --> 00:01:20,560
Absolutely.

30
00:01:20,560 --> 00:01:23,650
Let's head into the clean room.

31
00:01:23,650 --> 00:01:26,710
You'll see the tripod
come into place

32
00:01:26,710 --> 00:01:28,510
just as I was saying upstairs.

33
00:01:28,510 --> 00:01:31,210
Now two of the
struts are the same.

34
00:01:31,210 --> 00:01:34,150
But one is actually different in
the sense that it has a hinge,

35
00:01:34,150 --> 00:01:37,030
and it folds underneath
when it's stowed.

36
00:01:37,030 --> 00:01:41,200
The entire Observatory
must be folded up

37
00:01:41,200 --> 00:01:43,447
so it fits in the Ariane 5.

38
00:01:43,447 --> 00:01:45,280
So the way you're doing
this test right now,

39
00:01:45,280 --> 00:01:49,060
this is not exactly the way it's
going to be in space, right?

40
00:01:49,060 --> 00:01:51,160
Yes, absolutely.

41
00:01:51,160 --> 00:01:55,450
This yellow tower effectively
creates a zero-g environment

42
00:01:55,450 --> 00:01:59,440
in the sense that it
doesn't allow the mid hinge

43
00:01:59,440 --> 00:02:02,630
to close on its own
when gravity takes over.

44
00:02:02,630 --> 00:02:05,710
We want to be able to control
every aspect of the operation

45
00:02:05,710 --> 00:02:07,330
of that closing of the hinge.

46
00:02:07,330 --> 00:02:10,449
Well, Mary, before the
deployment is complete,

47
00:02:10,449 --> 00:02:12,800
how about we go upstairs to
get a different perspective?

48
00:02:12,800 --> 00:02:14,592
But, first, we need to
put these blue masks

49
00:02:14,592 --> 00:02:17,890
on because we'll be in such
close proximity to the mirrors.

50
00:02:17,890 --> 00:02:18,670
OK.

51
00:02:18,670 --> 00:02:20,650
How big are these struts anyway?

52
00:02:20,650 --> 00:02:24,640
The distance between the
center of the backplane

53
00:02:24,640 --> 00:02:28,780
and the secondary
mirror is about 25 feet.

54
00:02:28,780 --> 00:02:30,980
So it's like a two-story
house or something.

55
00:02:30,980 --> 00:02:32,890
That's probably a
very good comparison.

56
00:02:32,890 --> 00:02:35,110
How strong are these struts?

57
00:02:35,110 --> 00:02:37,270
These struts are very
strong to withstand

58
00:02:37,270 --> 00:02:41,560
the stresses of very, very
cold temperatures of space.

59
00:02:41,560 --> 00:02:44,560
They are the hollow
composite tubes.

60
00:02:44,560 --> 00:02:47,980
And the material is
about 40,007 inch thick.

61
00:02:47,980 --> 00:02:49,150
So it's not very heavy?

62
00:02:49,150 --> 00:02:52,940
No, they're extremely light,
but they're also very strong.

63
00:02:52,940 --> 00:02:55,630
How precise do you have
to be with the positioning

64
00:02:55,630 --> 00:02:56,950
of that secondary mirror?

65
00:02:56,950 --> 00:03:00,280
Each time we deploy
the secondary mirror

66
00:03:00,280 --> 00:03:03,430
into the same position
that it will be in space,

67
00:03:03,430 --> 00:03:06,843
it is within 1
millimeter every time.

68
00:03:06,843 --> 00:03:08,260
Well, thanks, Adam,
for helping us

69
00:03:08,260 --> 00:03:10,300
understand more about
how the secondary mirror

70
00:03:10,300 --> 00:03:11,520
will be deployed.

71
00:03:11,520 --> 00:03:12,020
Thank you.

72
00:03:12,020 --> 00:03:12,970
It was my pleasure.

73
00:03:12,970 --> 00:03:16,540
The deployment of the secondary
mirror happens on the 11th day

74
00:03:16,540 --> 00:03:19,060
after launch and is
one of the last steps

75
00:03:19,060 --> 00:03:21,310
the Webb Telescope goes
through before it's

76
00:03:21,310 --> 00:03:23,320
considered fully deployed.

77
00:03:23,320 --> 00:03:26,590
Thanks for joining us for this
edition of Behind the Webb.

78
00:03:26,590 --> 00:03:29,940
[LIVELY MUSIC]

79
00:03:29,940 --> 00:03:32,000