GEDI is NASA's Laser Mission to Measure Trees - Our Planet
GEDI is NASA's Laser Mission to Measure Trees. It is attached to the International Space Station (ISS) and weighs about a thousand pounds (454 kg) and looks like a refrigerator. It has a telescope of about 80 cm (31 in) in diameter. It has three laser ports and shoots out four laser beams that are then dithered, really quickly, in between shots. It makes one laser look like two. So GEDI is a laser altimeter. We have lasers that emit pulses of light, they travel down to the Earth, they get reflected from the Earth, and then we receive the reflection. We time how long it gets there, which allows us to measure the range to the surface. When the pulse of light hits the surface, it gets distorted and stretched out by any structure that is there.