Earth observation satellite

There are two main ways to capture images. One is the optical satellite, which takes pictures of the scene lit by sunlight, like a camera. The other is the radar satellite (SAR), which sends out radio waves and builds an image from what bounces back. Because a radar satellite sends its own waves, it can image at night and through clouds.

These satellites are used for weather forecasts, crop yields, assessing wildfire and flood damage, and making maps. They also watch military sites and the movement of ships in ports, so they touch on security too. These days, many small satellites are flown to photograph the same place often, and AI reads the pictures.

Just as a doctor checks your body's changes through regular checkups, an observation satellite photographs the Earth again and again to see what has changed and where.

The pictures taken from above that you see in the news come from here, from typhoon tracks to grain harvest forecasts to satellite photos in war reporting. Companies that sell satellite images make up one branch of the space industry.