1 00:00:00,000 --> 00:00:02,900 Welcome to the NASA Goddard Space Flight Center 2 00:00:02,900 --> 00:00:03,900 where we're building the 3 00:00:03,900 --> 00:00:06,660 Laser Communication Relay Demonstration (LCRD). 4 00:00:06,660 --> 00:00:09,420 LCRD is a technology demonstration mission 5 00:00:09,420 --> 00:00:11,490 that will use infrared lasers to send 6 00:00:11,490 --> 00:00:13,249 and receive data above gigabit 7 00:00:13,249 --> 00:00:15,529 per second in a relay capacity. 8 00:00:15,529 --> 00:00:17,800 Multiple systems going to the payload 9 00:00:17,800 --> 00:00:20,760 LCRD will carry two optical modules or telescopes 10 00:00:20,760 --> 00:00:22,470 where the data encoded lasers will be 11 00:00:22,470 --> 00:00:23,920 transmitted and received 12 00:00:23,930 --> 00:00:26,400 and two integrated modems to modulate the data 13 00:00:26,400 --> 00:00:27,720 onto the waves. 14 00:00:27,720 --> 00:00:29,099 Two control electronic 15 00:00:29,100 --> 00:00:31,120 boxes command the optical modules 16 00:00:31,120 --> 00:00:33,360 while a switching unit provides the ability to 17 00:00:33,360 --> 00:00:35,520 relay between the two sides of the payload. 18 00:00:35,520 --> 00:00:36,540 Today we're going to take a 19 00:00:36,540 --> 00:00:38,129 closer look at the optical modules and 20 00:00:38,129 --> 00:00:40,400 how we're developing those. Come on in. 21 00:00:40,400 --> 00:00:42,130 22 00:00:42,130 --> 00:00:44,710 Russell is the lead for LCRD's optical module 23 00:00:44,710 --> 00:00:46,090 development and he's going to show us how 24 00:00:46,090 --> 00:00:48,320 things are going today. How are you doing Russ? 25 00:00:48,320 --> 00:00:50,440 Great, you ready to take a look at the optical modules? 26 00:00:50,440 --> 00:00:52,000 Let's do it. 27 00:00:52,000 --> 00:00:56,960 28 00:00:56,960 --> 00:00:59,420 Now can you tell me about the optical module? 29 00:00:59,420 --> 00:01:01,420 What is it and what does it do? 30 00:01:01,449 --> 00:01:03,430 So the optical module is the device that points 31 00:01:03,430 --> 00:01:05,260 the down link beam at the ground station 32 00:01:05,260 --> 00:01:07,420 and it also gathers the light coming up 33 00:01:07,420 --> 00:01:08,770 from the ground station to the payload 34 00:01:08,770 --> 00:01:11,110 it responds to commands from the controller 35 00:01:11,110 --> 00:01:13,000 electronics and it's connected to modem 36 00:01:13,000 --> 00:01:14,780 via these two optical fibers. 37 00:01:14,780 --> 00:01:17,080 Ok, I see now so 38 00:01:17,080 --> 00:01:19,270 can you break it down a little bit for me, 39 00:01:19,270 --> 00:01:21,369 I know there's a lot of smaller assembly 40 00:01:21,369 --> 00:01:23,200 that go into the overall optical module, 41 00:01:23,200 --> 00:01:25,980 like the gimbal, what's the gimbal what does that do? 42 00:01:25,980 --> 00:01:27,340 The gimbal is right over here. 43 00:01:27,340 --> 00:01:29,340 The optical module has a two-axis gimball. 44 00:01:29,350 --> 00:01:32,050 One of the actuators controls east-west 45 00:01:32,050 --> 00:01:33,369 pointing when we're on orbit and the 46 00:01:33,369 --> 00:01:34,749 other one controls north-south. 47 00:01:34,749 --> 00:01:37,360 They both take extremely small steps 48 00:01:37,360 --> 00:01:40,960 OK, so mounted on the gimbal is 49 00:01:40,960 --> 00:01:42,909 the optical head, which is a combination of 50 00:01:42,909 --> 00:01:44,309 a few sub-assembles. 51 00:01:44,309 --> 00:01:47,200 What are those sub-assembles and what do they do? 52 00:01:47,200 --> 00:01:50,280 The Optical head is made up of the solar window assembly 53 00:01:50,280 --> 00:01:51,320 the optical assembly, 54 00:01:51,320 --> 00:01:52,460 which we can't see 55 00:01:52,460 --> 00:01:54,320 and the Inertial Stable Platform 56 00:01:54,320 --> 00:01:56,860 and the solar window assembly has a large mirror 57 00:01:56,860 --> 00:01:58,360 with a special optical coating. 58 00:01:58,360 --> 00:02:00,480 It's a mirror and most wavelength but it lets 59 00:02:00,480 --> 00:02:02,720 the LCRD wavelengths pass through. 60 00:02:02,720 --> 00:02:05,740 OK, alright, so I know in Lasercom 61 00:02:05,750 --> 00:02:08,030 you need the steady and stable beam in order 62 00:02:08,030 --> 00:02:10,090 to hit the ground station. 63 00:02:10,090 --> 00:02:12,450 How do you account for that on the spacecraft? 64 00:02:12,450 --> 00:02:14,550 How do you keep the beam steady? 65 00:02:14,550 --> 00:02:16,490 That's the job of the Inertially Stable Platform (ISP) 66 00:02:16,500 --> 00:02:18,960 so the optical assembly is mounted on the ISP 67 00:02:18,960 --> 00:02:21,940 and the ISP has some sensors that measures 68 00:02:21,940 --> 00:02:22,880 tip and tilt. 69 00:02:22,880 --> 00:02:25,180 It also has some actuators that are controlled 70 00:02:25,180 --> 00:02:26,900 by the controller electronics 71 00:02:26,900 --> 00:02:30,020 and those are commanded to minimize tip and tilt. 72 00:02:30,020 --> 00:02:34,480 OK, so I hear that the optical assembly is the 73 00:02:34,490 --> 00:02:36,980 most complex and complicated part of the 74 00:02:36,980 --> 00:02:38,300 optical module. Why is that? 75 00:02:38,300 --> 00:02:39,900 Why is it so complicated? 76 00:02:39,900 --> 00:02:42,400 It is complicated. It's made up of two different things 77 00:02:42,400 --> 00:02:44,740 there's a telescope that sits up front 78 00:02:44,740 --> 00:02:46,900 and then a small optics assembly in the back. 79 00:02:46,900 --> 00:02:48,620 The small optics assembly has 80 00:02:48,620 --> 00:02:51,280 several optics that about the size of a dime 81 00:02:51,280 --> 00:02:53,260 each have their own special coating 82 00:02:53,260 --> 00:02:55,420 that rowdy different LCRD wavelengths 83 00:02:55,420 --> 00:02:56,580 where they need to go 84 00:02:56,580 --> 00:02:57,800 and they're also 85 00:02:57,800 --> 00:03:00,280 actuators the small optics assembly that 86 00:03:00,280 --> 00:03:02,080 move the fibers around that are carrying 87 00:03:02,080 --> 00:03:03,380 the data. 88 00:03:03,380 --> 00:03:07,320 OK, speaking of actuators I heard that 89 00:03:07,320 --> 00:03:11,740 there's this rubber o-ring that's around the latch 90 00:03:11,740 --> 00:03:14,180 and in order to deploy the optical module 91 00:03:14,180 --> 00:03:16,800 you have to use paraffin actuators 92 00:03:16,800 --> 00:03:18,000 to deploy it, can you talk to 93 00:03:18,000 --> 00:03:20,360 me about that? What are the paraffin actuators? 94 00:03:20,360 --> 00:03:21,900 Sure we need to have the OM 95 00:03:21,900 --> 00:03:24,959 like this stowed at launch that way the 96 00:03:24,959 --> 00:03:27,000 latch covers the solar window assembly 97 00:03:27,000 --> 00:03:29,060 and supports the optical head 98 00:03:29,060 --> 00:03:31,820 and when we get on orbit we warm up the wax and 99 00:03:31,820 --> 00:03:34,040 one of the paraffin actuators down here. 100 00:03:34,040 --> 00:03:36,620 When it warms up it acts as a pin puller 101 00:03:36,620 --> 00:03:39,891 the latch rotates back and then we can begin operations. 102 00:03:39,900 --> 00:03:42,700 Awesome! Can go check out the test set up? 103 00:03:42,700 --> 00:03:43,200 Sure! 104 00:03:43,200 --> 00:03:43,800 Thanks! 105 00:03:43,800 --> 00:03:45,000 106 00:03:45,000 --> 00:03:47,340 Now this is a really impressive setup is 107 00:03:47,340 --> 00:03:48,959 this where you test the optical modules? 108 00:03:48,960 --> 00:03:51,060 It is, we put the optical module right 109 00:03:51,060 --> 00:03:52,980 here on the jitter table and for some 110 00:03:52,980 --> 00:03:55,170 tests we use these small shakers to disturb 111 00:03:55,170 --> 00:03:57,120 the optical modules. We need to make sure 112 00:03:57,120 --> 00:03:58,590 that the Inertial Stable Platform is 113 00:03:58,590 --> 00:03:59,720 doing its job. 114 00:03:59,720 --> 00:04:01,620 Our host spacecraft has moving parts 115 00:04:01,620 --> 00:04:03,660 which generate disturbances. 116 00:04:03,660 --> 00:04:06,480 OK, and over here I noticed that there's 117 00:04:06,480 --> 00:04:08,480 these really cool looking mirrors. 118 00:04:08,480 --> 00:04:10,800 Why do you need so many of them? 119 00:04:10,800 --> 00:04:13,580 Well these large flat mirrors are for aligning the optical 120 00:04:13,580 --> 00:04:15,080 modules to the optimal test set 121 00:04:15,080 --> 00:04:17,239 and we have three of them because we want to be 122 00:04:17,240 --> 00:04:18,980 able to set up two optical modules 123 00:04:18,980 --> 00:04:21,040 for testing at the same time. 124 00:04:21,520 --> 00:04:22,360 Awesome! 125 00:04:22,580 --> 00:04:25,080 And I noticed the thermal vacuums is in here too. 126 00:04:25,080 --> 00:04:27,800 Besides when the optical modules are integrated 127 00:04:27,800 --> 00:04:29,210 with the payload and the payload goes 128 00:04:29,210 --> 00:04:30,890 off to be made it with the host 129 00:04:30,890 --> 00:04:32,530 spacecraft with the optical modules ever 130 00:04:32,540 --> 00:04:33,740 leave the cleanroom? 131 00:04:33,740 --> 00:04:36,120 The only time to leave is for vibration testing 132 00:04:36,120 --> 00:04:37,940 and that's because we don't need the optical test set 133 00:04:37,940 --> 00:04:38,740 for that. 134 00:04:38,740 --> 00:04:40,680 For everything else we need the OTS 135 00:04:40,680 --> 00:04:42,780 it's very big, it took a long time to assemble 136 00:04:42,780 --> 00:04:43,500 in the line 137 00:04:43,500 --> 00:04:45,760 so instead of moving the OTS, we bring the test 138 00:04:45,760 --> 00:04:46,640 equipment in here, 139 00:04:46,640 --> 00:04:48,330 including the thermal vacuum chamber. 140 00:04:48,330 --> 00:04:50,560 Russ, thank you so much for letting us come in here today 141 00:04:50,570 --> 00:04:52,730 and learn more about the optical modules 142 00:04:52,730 --> 00:04:55,430 Want to learn more about LCRD? 143 00:04:55,440 --> 00:04:58,560 Visit LCRD.GSFC.NASA.GOV 144 00:04:58,560 --> 00:05:01,980