A remote-sensing satellite (also spelled remote sensing satellite) is a satellite that studies the Earth's surface and atmosphere. It uses powerful cameras to scan the planet. It then sends back data about global environments to ground-based stations.
The first remote sensing satellites recorded images on film. All current satellites use digital systems to record the images, and have many advantages over film systems. In particular, digital image data can be transmitted to ground-based stations and digital data are able to be processed on computers.