Earth observation satellites are Earth-orbiting spacecraft with sensors used to collect imagery and measurements of the surface of the earth. These satellites are used to monitor short-term weather, long-term climate change, natural disasters. Earth observations satellites provide information for research subjects that benefit from looking at Earth’s surface from above (such as meteorology, oceanography, terrestrial ecology, glaciology, atmospheric science, hydrology, geology, and many more). Types of sensors on these satellites include passive and active remote sensors. Sensors on Earth observation satellites often take measurements of emitted energy over some portion of the electromagnetic spectrum (e.g., UV, visible, infrared, microwave, or radio). The invention of climate research through the use of satellite remote telemetry began in the 1960s through development of space probes to study other planets. During the U.S. economic decline in 1977, with much of NASA's money going toward the shuttle program, the Reagan Administration proposed to reduce spending on planetary exploration. During this time, new scientific evidence emerged from ice and sediment cores that Earth's climate had experienced rapid changes in temperature, running contrary to the previously held belief that the climate changed on a geological time scale. These changes increased political interest in gathering remote-sensing data on the Earth itself and stimulated the science of climatology.

Classification

The lists below classify Earth observation satellites in two large groups: satellites operated by government agencies of one or more countries (public domain) versus commercial satellites built and maintained by companies (private domain). These lists focus on currently active missions, rather than inactive retired missions or planned future missions. However, some examples of past and future satellites are included. Active, inactive, or planned classifications are relevant as of 2021.

Public domain or government agency satellites

Active government satellites

Inactive government satellites

Planned government satellites

Private or commercial satellites

Active commercial satellites

Inactive commercial satellites

Planned commercial satellites