WEBVTT FILE 1 00:00:00.010 --> 00:00:08.040 [SFX] 2 00:00:08.040 --> 00:00:12.090 Hey John, I'm finished with your model. 3 00:00:12.090 --> 00:00:14.150 Thanks 4 00:00:14.150 --> 00:00:16.190 So you looking forward to the launch? 5 00:00:16.190 --> 00:00:19.200 You have no idea. 6 00:00:19.200 --> 00:00:24.230 [music and sounds of children] 7 00:00:24.230 --> 00:00:28.250 My project is a LiDAR instrument called CATS. 8 00:00:28.250 --> 00:00:32.310 And it measure clouds and pollution in the Earth's atmosphere. 9 00:00:32.310 --> 00:00:36.330 These are important because they affect society in many ways. 10 00:00:36.330 --> 00:00:39.400 So Little Johnny, how does this LiDAR work? 11 00:00:39.400 --> 00:00:41.460 LiDAR is actually quite simple. 12 00:00:41.460 --> 00:00:47.480 You shine laser light at the Earth's atmosphere and measure the amount of light scattered back. 13 00:00:47.480 --> 00:00:48.520 My instrument... [voice fades out] 14 00:00:48.520 --> 00:00:53.550 Today, a team at NASA Goddard is preparing to demonstrate, 15 00:00:53.550 --> 00:00:58.580 for the fist time in space, a 3-wavelength, laser remote sensing instrument. 16 00:00:58.580 --> 00:01:04.610 The Cloud-Aerosol Transport System, or CATS, will measure clouds and aerosols in the Earth's atmosphere. 17 00:01:04.610 --> 00:01:10.630 To obtain this data, CATS uses a laser that generates 3 wavelengths or "colors," of light. 18 00:01:10.630 --> 00:01:15.650 Internal to the laser, special optical crystals are used to generate these wavelengths 19 00:01:15.650 --> 00:01:19.680 by adding the energy of two photons, to make a single new photon. 20 00:01:19.680 --> 00:01:23.700 The final output beam is made up of all three wavelengths 21 00:01:23.700 --> 00:01:27.720 and these photons are transmitted in groups, towards the atmosphere, at the speed of light. 22 00:01:27.720 --> 00:01:32.750 As photons encounter clouds or particles, scattering of the laser beam occurs. 23 00:01:32.750 --> 00:01:36.770 Very few of the photons scatter directly back to the optical telescope, 24 00:01:36.770 --> 00:01:41.810 but the ones that return, are collected and counted by sensitive detectors and electronics. 25 00:01:41.810 --> 00:01:48.870 By timing the difference between emission and detection, the precise altitude of the particles can be determined. 26 00:01:48.870 --> 00:01:52.910 While monitoring global hazards from above, 27 00:01:52.910 --> 00:01:56.940 CATS will determine the height, thickness and the extent of smoke, dust particles, 28 00:01:56.940 --> 00:01:58.970 and volcanic ash in our atmosphere. 29 00:01:58.970 --> 00:02:04.000 Improving cloud data will allow scientist to create more accurate climate models, 30 00:02:04.000 --> 00:02:08.020 which in turn, will improve air quality forecast and health risk alerts. 31 00:02:08.020 --> 00:02:12.030 This cost-effective, technology demonstration will utilize 32 00:02:12.030 --> 00:02:18.070 the International Space Station as a scientific platform for up to 3 years. 33 00:02:18.070 --> 00:02:24.100 Once proven, the CATS technology can be used to further a larger, free-flier satellite mission. 34 00:02:24.100 --> 00:02:28.120 Until then, CATS will provide information that can help us better understand 35 00:02:28.120 --> 00:02:32.150 Earth's complex atmospheric processes. 36 00:02:32.150 --> 00:02:38.170 [Music/SFX] 37 00:02:38.170 --> 00:02:46.260 [SFX] 38 00:02:46.260 --> 00:02:49.550