Putting satellites in orbit is just one part of developing a satellite system. The satellite must obtain useful information via various sensors including visual television and still-camera systems, passive sensors such as infra-red heat detectors, and active microwave systems that transmit signals and receive reflected return signals from various atmospheric and oceanographic phenomena. This information must then be transmitted to ground stations that receive and process the data for inclusion in various weather and climate products. All of this, plus the skilled scientists, engineers, and technicians that keep the various components operating, make up the NOAA satellite systems that have proven so beneficial to the people of the United States.