Explore how lasers onboard satellites are used to map our planet and beyond.
While most satellites work like digital cameras and passively record a narrow spectrum of emitted or reflected radiation—visible light, in a camera's case—those equipped with lidar (Light Detection And Ranging) instruments use rapidly pulsating laser beams to actively detect specific features. Measurements made with lidar in recent years have provided detailed information about the topography of Earth's surface and characteristics of its atmosphere. ICESat, a NASA laser altimetry mission launched in 2003, monitored the changing elevation of Arctic and Antarctic ice sheets and created 3-D maps of forest canopies throughout the world. Since 2006 NASA's CALIPSO satellite has detected clouds and airborne particles that reflect or absorb heat and help drive global climate. Watch the video below to learn how this advanced technology is used to study the contours of ice, clouds, trees, and even the cratered terrain of the moon.