WEBVTT 00:00:00.000 --> 00:00:01.482 align:middle line:90% [MUSIC PLAYING] 00:00:01.482 --> 00:00:12.295 align:middle line:90% 00:00:12.295 --> 00:00:14.420 align:middle line:84% One of the most striking features of the James Webb 00:00:14.420 --> 00:00:16.550 align:middle line:84% Space Telescope is the sunshield, 00:00:16.550 --> 00:00:19.700 align:middle line:84% probably because it's about the size of a tennis court. 00:00:19.700 --> 00:00:22.620 align:middle line:84% Now that's too big to be sent into space that way. 00:00:22.620 --> 00:00:25.730 align:middle line:84% So at launch, it's in a folded up configuration. 00:00:25.730 --> 00:00:27.650 align:middle line:84% When the James Webb Space Telescope 00:00:27.650 --> 00:00:31.040 align:middle line:84% reaches its destination one million miles from Earth, 00:00:31.040 --> 00:00:33.180 align:middle line:90% the sunshield is then deployed. 00:00:33.180 --> 00:00:36.110 align:middle line:84% Different contractors are working right now together 00:00:36.110 --> 00:00:38.630 align:middle line:84% on a mechanism or several mechanisms 00:00:38.630 --> 00:00:40.640 align:middle line:84% to control the sunshield's deployment. 00:00:40.640 --> 00:00:44.300 align:middle line:84% One of those is Northrop Grumman's Astro Aerospace here 00:00:44.300 --> 00:00:46.490 align:middle line:90% in Carpinteria, California. 00:00:46.490 --> 00:00:49.010 align:middle line:84% One of the lead project engineers here at Astro 00:00:49.010 --> 00:00:50.820 align:middle line:90% Aerospace is Larry Heinlein. 00:00:50.820 --> 00:00:51.320 align:middle line:90% Hey, Larry. 00:00:51.320 --> 00:00:53.930 align:middle line:84% So what exactly are you guys working on here? 00:00:53.930 --> 00:00:57.440 align:middle line:84% This is a mid-boom assembly for the James Webb Space Telescope. 00:00:57.440 --> 00:00:59.780 align:middle line:84% So what exactly is mid-boom assembly? 00:00:59.780 --> 00:01:02.270 align:middle line:90% So there's one base tube. 00:01:02.270 --> 00:01:04.280 align:middle line:84% And there's five deploying tubes. 00:01:04.280 --> 00:01:07.430 align:middle line:84% The five deploying tubes deploy out. 00:01:07.430 --> 00:01:09.140 align:middle line:84% And as they deploy out, they unfold 00:01:09.140 --> 00:01:11.360 align:middle line:90% the layers of the sunshield. 00:01:11.360 --> 00:01:14.130 align:middle line:90% [MECHANICAL WHIRRING] 00:01:14.130 --> 00:01:17.250 align:middle line:84% And you have separate tubes because? 00:01:17.250 --> 00:01:21.330 align:middle line:84% Because during launch, it needs to stove within about five feet 00:01:21.330 --> 00:01:22.350 align:middle line:90% of length. 00:01:22.350 --> 00:01:24.750 align:middle line:84% And when it's fully deployed, it's about 25 feet. 00:01:24.750 --> 00:01:28.170 align:middle line:84% But on the end of that boom is a 5-foot long spreader bar, 00:01:28.170 --> 00:01:32.760 align:middle line:84% which the sunshield layers are attached to. 00:01:32.760 --> 00:01:33.540 align:middle line:90% Oh, OK. 00:01:33.540 --> 00:01:36.510 align:middle line:84% That puts the layers of the sunshield in position, right? 00:01:36.510 --> 00:01:37.230 align:middle line:90% That's correct. 00:01:37.230 --> 00:01:40.470 align:middle line:84% OK, kind of reminds me of an antenna of sorts. 00:01:40.470 --> 00:01:43.740 align:middle line:84% Yes, it kind of looks like your old-fashioned deploying 00:01:43.740 --> 00:01:45.570 align:middle line:90% antenna. 00:01:45.570 --> 00:01:50.670 align:middle line:84% So, Larry, how do you make these tubes extend? 00:01:50.670 --> 00:01:53.250 align:middle line:84% Well, inside the carbon graphite tubes 00:01:53.250 --> 00:01:55.140 align:middle line:84% is something that we call the STEM deployer. 00:01:55.140 --> 00:01:57.960 align:middle line:84% And Tim Martinez will help explain that. 00:01:57.960 --> 00:01:59.970 align:middle line:90% This is called a STEM deployer. 00:01:59.970 --> 00:02:02.850 align:middle line:84% And this amounts to the bottom of the base tube. 00:02:02.850 --> 00:02:04.950 align:middle line:84% And this is what drives the assembly 00:02:04.950 --> 00:02:05.970 align:middle line:90% and pushes the tubes up. 00:02:05.970 --> 00:02:08.520 align:middle line:90% 00:02:08.520 --> 00:02:10.949 align:middle line:84% And the way it works is that it pushes 00:02:10.949 --> 00:02:13.710 align:middle line:90% this material called STEM out. 00:02:13.710 --> 00:02:16.090 align:middle line:84% And the concept is like a tape measure. 00:02:16.090 --> 00:02:19.540 align:middle line:84% So when it's coming out, it becomes round. 00:02:19.540 --> 00:02:23.460 align:middle line:84% But when it's around this spool that's inside, it's flat. 00:02:23.460 --> 00:02:27.330 align:middle line:84% And there's a motor that drives the whole thing out. 00:02:27.330 --> 00:02:29.310 align:middle line:90% It doesn't feel very heavy. 00:02:29.310 --> 00:02:30.150 align:middle line:90% But it's strong? 00:02:30.150 --> 00:02:32.760 align:middle line:84% Yeah, it's made out of very thin sheet 00:02:32.760 --> 00:02:35.760 align:middle line:90% of corrosion resistant steel. 00:02:35.760 --> 00:02:37.470 align:middle line:84% But that's what's great about it. 00:02:37.470 --> 00:02:38.250 align:middle line:90% It's really light. 00:02:38.250 --> 00:02:40.590 align:middle line:90% But it can push up 100 pounds. 00:02:40.590 --> 00:02:43.260 align:middle line:84% And then there's also a requirement to pull back. 00:02:43.260 --> 00:02:46.440 align:middle line:84% And so it can actually pull back 400 pounds. 00:02:46.440 --> 00:02:48.660 align:middle line:84% And why would you even pull back? 00:02:48.660 --> 00:02:53.250 align:middle line:84% Once the booms are completely deployed, it pulls back. 00:02:53.250 --> 00:02:56.040 align:middle line:84% And the tubes are connected to a cable which 00:02:56.040 --> 00:03:00.480 align:middle line:84% tensions the whole sunshield and separates the five membranes. 00:03:00.480 --> 00:03:02.400 align:middle line:84% Thanks for joining us for another edition 00:03:02.400 --> 00:03:03.750 align:middle line:90% of Behind the Webb. 00:03:03.750 --> 00:03:06.200 align:middle line:90% [MUSIC PLAYING] 00:03:06.200 --> 00:03:08.000 align:middle line:90%