Many different types of instruments are flown on space missions, employing various measurement technologies and techniques – both active and passive – that utilise a wide range of the electromagnetic spectrum.

CEOS agencies are operating or planning around 260 satellites with an Earth observation mission over the next 15 years. These satellites will carry over 400 different instruments.

This sustained investment by the space agencies will ensure the provision of information of unique value in both public and commercial spheres, derived from the measurements of a diverse range of geophysical parameters and phenomena.

Public awareness of the applications of Earth observation satellites tends to focus on imagery (through internet applications such as Google Earth and Microsoft Live Local) and on meteorology, combined with the knowledge that data from meteorological satellites are used on a daily basis for the Numerical Weather Prediction models which drive our weather forecasting capabilities.

Meteorology is certainly one of the most established disciplines for application of Earth observation satellite data, with satellite-derived information being used operationally by weather services worldwide. Dedicated meteorological satellites have been in operation for several decades, providing continuous coverage of much of the globe.

In practice, only 80 missions, or around a third of those planned for the next 15 years, could be described as having meteorology as a primary objective. The other 180 missions will be applied to a diverse range of research, operational and commercial activities.

Given the significance of the issues, and the unique role of satellite Earth observations, many will be dedicated to different aspects of climate or environmental studies. Others will be employed to assist decision-making in strategic planning and management of industrial, economic and natural resources, including the provision of information required for sustainable development strategies. New missions serving operational needs related to land, ocean and atmospheric composition have recently been launched or will be in the near future.

Increased frequency of satellite measurements, improved satellite and sensor technology, and easier access and interpretation of Earth observation data have all contributed to increased demand for satellite data, and to the reality of new operational services being established in the near future for several domains, including monitoring of key oceanic and atmospheric parameters. Information on the various missions and instruments, their capabilities and their applications is given in sections 8 (missions) and 9 (instruments).