- Meteorology, for immediate weather forecasting and climate change research ;
- Life sciences, to gain insights into the Earth system and better protect the environment, by observing land surfaces (plant cover, land use and land cover, and the polar ice caps), oceans, and atmospheric and geophysical phenomena ;
- Sciences of the Universe, to further our understanding of the origins of the Universe and of life on Earth. Such satellites are dedicated to solar system exploration and astronomy (in which case they are more often called probes), and to fundamental physics and exobiology ;
- Telecommunications missions, using the satellite as a relay for telephone, television, multimedia and data transmission ;
- Satellite navigation, for precise positioning anytime, anywhere on the globe. Such missions are important for maritime navigation, traffic control and search and rescue ;
- Military activities, mostly using civil space technologies for surveillance of theatres of operations and rapid communications guaranteeing transmission integrity and security.
Depending on its mission, the satellite’s payload may comprise imaging instruments, measuring instruments or transponders, which amplify and transmit radio signals between the Earth and the satellite.