Satellites and space probes are launched on their missions to a wide variety of destinations. Some satellites are sent into Earth orbit to look down at Earth's surface or atmosphere; others aim outward, to study the Moon, other planets, or the universe itself. Probes are sent beyond Earth orbit to pass near, land on, or orbit other planets or the Moon. No matter what their eventual destination, the primary objective of sending these craft into space is to gather information and relay it back to Earth in some direct or indirect way. To collect information, these space vehicles must carry with them some means of collecting and distinguishing this data. Sensors are one type of instrument that can collect information.

Sensors, as applied to spacecraft, are instruments and devices that can detect alterations or variations in the space environment and send electrical, radio, or other types of signals...