CATS in Space Keep Eyes on Atmosphere

Narration: Mike Velle


[SFX] Hey John, I'm finished with your model. Thanks So you looking forward to the launch? You have no idea. [music and sounds of children] My project is a LiDAR instrument called CATS. And it measure clouds and pollution in the Earth's atmosphere. These are important because they affect society in many ways. So Little Johnny, how does this LiDAR work? LiDAR is actually quite simple. You shine laser light at the Earth's atmosphere and measure the amount of light scattered back. My instrument... [voice fades out] Today, a team at NASA Goddard is preparing to demonstrate, for the fist time in space, a 3-wavelength, laser remote sensing instrument. The Cloud-Aerosol Transport System, or CATS, will measure clouds and aerosols in the Earth's atmosphere. To obtain this data, CATS uses a laser that generates 3 wavelengths or "colors," of light. Internal to the laser, special optical crystals are used to generate these wavelengths by adding the energy of two photons, to make a single new photon. The final output beam is made up of all three wavelengths and these photons are transmitted in groups, towards the atmosphere, at the speed of light. As photons encounter clouds or particles, scattering of the laser beam occurs. Very few of the photons scatter directly back to the optical telescope, but the ones that return, are collected and counted by sensitive detectors and electronics. By timing the difference between emission and detection, the precise altitude of the particles can be determined. While monitoring global hazards from above, CATS will determine the height, thickness and the extent of smoke, dust particles, and volcanic ash in our atmosphere. Improving cloud data will allow scientist to create more accurate climate models, which in turn, will improve air quality forecast and health risk alerts. This cost-effective, technology demonstration will utilize the International Space Station as a scientific platform for up to 3 years. Once proven, the CATS technology can be used to further a larger, free-flier satellite mission. Until then, CATS will provide information that can help us better understand Earth's complex atmospheric processes. [Music/SFX] [SFX]