WEBVTT 00:00:00.000 --> 00:00:01.473 align:middle line:90% [MUSIC PLAYING] 00:00:01.473 --> 00:00:13.770 align:middle line:90% 00:00:13.770 --> 00:00:17.160 align:middle line:84% Mirrors on a telescope are often coated with some kind of metal 00:00:17.160 --> 00:00:20.290 align:middle line:84% in order to reflect as much light as possible. 00:00:20.290 --> 00:00:23.130 align:middle line:84% Now the type of metal depends upon the kind of light 00:00:23.130 --> 00:00:24.810 align:middle line:90% the telescope is looking at. 00:00:24.810 --> 00:00:28.410 align:middle line:84% The James Webb Space Telescope is looking at infrared light. 00:00:28.410 --> 00:00:31.530 align:middle line:84% And for that, gold is the ideal choice. 00:00:31.530 --> 00:00:34.470 align:middle line:84% To find out how the gold is put onto the mirrors of the James 00:00:34.470 --> 00:00:36.210 align:middle line:84% Webb Space Telescope, we are here 00:00:36.210 --> 00:00:39.330 align:middle line:84% at Quantum Coating in Moorestown, New Jersey. 00:00:39.330 --> 00:00:42.060 align:middle line:84% So, Ian, how much gold are we talking about? 00:00:42.060 --> 00:00:42.840 align:middle line:90% Enough for a ring? 00:00:42.840 --> 00:00:43.890 align:middle line:90% Not even that. 00:00:43.890 --> 00:00:46.680 align:middle line:84% Well, it depends on how big your ring is, of course. 00:00:46.680 --> 00:00:50.970 align:middle line:84% But the thickness of the coating is almost unimaginably small. 00:00:50.970 --> 00:00:53.190 align:middle line:84% To give an example, this piece of paper 00:00:53.190 --> 00:00:55.930 align:middle line:84% is about one thousandth of an inch. 00:00:55.930 --> 00:00:59.460 align:middle line:84% We could take 1,000 gold coatings, 00:00:59.460 --> 00:01:01.863 align:middle line:84% stack them all side by side, and they 00:01:01.863 --> 00:01:03.780 align:middle line:84% would be the thickness of this piece of paper. 00:01:03.780 --> 00:01:06.030 align:middle line:84% In terms of the amount of gold that we need, 00:01:06.030 --> 00:01:09.030 align:middle line:84% it comes to three grams of material. 00:01:09.030 --> 00:01:10.342 align:middle line:90% And three grams looks like-- 00:01:10.342 --> 00:01:11.550 align:middle line:90% Three grams-- I have it here. 00:01:11.550 --> 00:01:12.540 align:middle line:90% --this. 00:01:12.540 --> 00:01:16.170 align:middle line:84% Wow, that's amazing considering how big the mirror is. 00:01:16.170 --> 00:01:18.900 align:middle line:84% That in mind, when it's spread out thin enough, 00:01:18.900 --> 00:01:21.060 align:middle line:84% it covers the whole surface of the hexagon. 00:01:21.060 --> 00:01:24.420 align:middle line:84% When you apply the coating, are we talking about a paint job? 00:01:24.420 --> 00:01:26.670 align:middle line:84% No, this is all vacuum deposition. 00:01:26.670 --> 00:01:28.800 align:middle line:84% It happens in a chamber where all of the air 00:01:28.800 --> 00:01:30.840 align:middle line:84% has been sucked out to create a vacuum. 00:01:30.840 --> 00:01:32.940 align:middle line:90% Then we vaporize the gold. 00:01:32.940 --> 00:01:35.220 align:middle line:90% We create a cloud of vapor. 00:01:35.220 --> 00:01:38.760 align:middle line:84% And that vapor condenses on the surface to form the film. 00:01:38.760 --> 00:01:42.120 align:middle line:84% And why do you choose to apply the gold that way? 00:01:42.120 --> 00:01:45.083 align:middle line:84% That's the way to get the maximum reflection. 00:01:45.083 --> 00:01:46.500 align:middle line:84% Spray painting or other techniques 00:01:46.500 --> 00:01:48.420 align:middle line:84% wouldn't give us enough reflection. 00:01:48.420 --> 00:01:52.500 align:middle line:84% And can we actually see the gold being applied to a mirror? 00:01:52.500 --> 00:01:53.332 align:middle line:90% Sure. 00:01:53.332 --> 00:01:55.290 align:middle line:84% Ty is the guy who operates the cutting machine. 00:01:55.290 --> 00:01:57.240 align:middle line:84% He'd be happy to show you how that works. 00:01:57.240 --> 00:01:58.042 align:middle line:90% Hey, Ty. 00:01:58.042 --> 00:01:59.250 align:middle line:90% Hey, how are you doing, Mary? 00:01:59.250 --> 00:02:02.560 align:middle line:84% I was told that a coating process is about to start. 00:02:02.560 --> 00:02:05.040 align:middle line:84% Sure, we're about to start the coating soon. 00:02:05.040 --> 00:02:05.860 align:middle line:90% Can we tag along? 00:02:05.860 --> 00:02:06.360 align:middle line:90% Sure. 00:02:06.360 --> 00:02:09.889 align:middle line:90% 00:02:09.889 --> 00:02:12.080 align:middle line:84% OK, see, what we're doing here now-- we're 00:02:12.080 --> 00:02:13.790 align:middle line:84% preparing the mirror for coating. 00:02:13.790 --> 00:02:17.660 align:middle line:84% Cleaning the mirror of any contaminants or any particles 00:02:17.660 --> 00:02:21.175 align:middle line:90% that could be on the mirror. 00:02:21.175 --> 00:02:22.550 align:middle line:84% So, Ty, what's going on here now? 00:02:22.550 --> 00:02:24.880 align:middle line:84% OK, well, now we're putting on the shield and the mask 00:02:24.880 --> 00:02:26.000 align:middle line:90% for the mirror. 00:02:26.000 --> 00:02:29.480 align:middle line:84% A coating can not be beyond a certain area on the mirror. 00:02:29.480 --> 00:02:31.550 align:middle line:84% So you want the gold to just be on the surface. 00:02:31.550 --> 00:02:32.780 align:middle line:84% Nothing on the sides or anything. 00:02:32.780 --> 00:02:33.260 align:middle line:90% Right. 00:02:33.260 --> 00:02:35.218 align:middle line:84% There's a bevel also on the edge of the mirror. 00:02:35.218 --> 00:02:39.130 align:middle line:84% We don't want any coating on the bevel either. 00:02:39.130 --> 00:02:41.170 align:middle line:90% How long is it's going to take? 00:02:41.170 --> 00:02:42.175 align:middle line:90% Maybe an hour in total. 00:02:42.175 --> 00:02:45.060 align:middle line:90% 00:02:45.060 --> 00:02:48.800 align:middle line:84% But I understand there are no cameras in the chamber. 00:02:48.800 --> 00:02:50.120 align:middle line:90% Can we see what's going on? 00:02:50.120 --> 00:02:52.550 align:middle line:84% We can take a look inside our viewport. 00:02:52.550 --> 00:02:55.680 align:middle line:84% We see the part rotating and we can see the glow dispersed 00:02:55.680 --> 00:02:56.180 align:middle line:90% right now. 00:02:56.180 --> 00:03:00.070 align:middle line:90% 00:03:00.070 --> 00:03:02.050 align:middle line:84% So, Ty, we couldn't show the actual company 00:03:02.050 --> 00:03:05.920 align:middle line:84% specific equipment that was used to apply the coating, 00:03:05.920 --> 00:03:07.960 align:middle line:84% but we get to see the gold-coated mirror, 00:03:07.960 --> 00:03:09.070 align:middle line:90% fresh out of the chamber. 00:03:09.070 --> 00:03:09.820 align:middle line:90% Yeah, that's neat. 00:03:09.820 --> 00:03:11.100 align:middle line:90% Look at it. 00:03:11.100 --> 00:03:12.530 align:middle line:90% The mirror is coated. 00:03:12.530 --> 00:03:13.712 align:middle line:90% Now we're all complete. 00:03:13.712 --> 00:03:15.670 align:middle line:84% And we're ready to ship it off to the customer. 00:03:15.670 --> 00:03:18.190 align:middle line:84% And they can begin their testing. 00:03:18.190 --> 00:03:19.780 align:middle line:84% Well, thanks so much for guiding us 00:03:19.780 --> 00:03:21.220 align:middle line:90% through your coating process. 00:03:21.220 --> 00:03:22.240 align:middle line:90% It was fascinating. 00:03:22.240 --> 00:03:23.930 align:middle line:90% Well, not a problem at all. 00:03:23.930 --> 00:03:26.080 align:middle line:84% Well, as you can see, gold isn't just 00:03:26.080 --> 00:03:29.110 align:middle line:84% a fashion accessory for the James Webb Space Telescope 00:03:29.110 --> 00:03:32.080 align:middle line:84% but a critical addition to making the telescope 00:03:32.080 --> 00:03:34.100 align:middle line:90% work its very best. 00:03:34.100 --> 00:03:36.250 align:middle line:84% Thanks for joining us for another edition 00:03:36.250 --> 00:03:37.630 align:middle line:90% of Behind the Webb. 00:03:37.630 --> 00:03:40.080 align:middle line:90% [MUSIC PLAYING] 00:03:40.080 --> 00:03:49.000 align:middle line:90%