ESA's Soil Moisture and Ocean Salinity (SMOS) mission has been designed to observe soil moisture over the Earth's landmasses and salinity over the oceans. Soil moisture data are urgently required for hydrological studies and data on ocean salinity are vital for improving our understanding of ocean circulation patterns.

As part of ESA's Living Planet programme, the Gravity field and steady-state Ocean Circulation Explorer (GOCE) is the first of a series of Earth Explorer satellites in orbit, designed to provide information for understanding critical Earth system variables. It has been developed to bring about a whole new level of understanding of one of the Earth's most fundamental forces of nature - the gravity field.

Envisat (ENVIronmental SATellite) is an advanced polar-orbiting Earth observation satellite which provides measurements of the atmosphere, ocean, land, and ice over a five year period. The Envisat satellite has an ambitious and innovative payload that ensures the continuity of the data measurements of the ERS satellites. The Envisat data supports Earth science research and allows monitoring of the evolution of environmental and climatic changes. Furthermore, the data facilitates the development of operational and commercial applications

The European Remote Sensing satellite, ERS-1, launched in 1991, was ESA's first sun-synchronous polar orbiting remote sensing mission, operated until March 2000. ERS-1 carried a comprehensive payload including an imaging Synthetic Aperture Radar (SAR), a radar altimeter and other powerful instruments to measure ocean surface temperature and winds at sea. ERS-2, which overlapped with ERS-1, was launched in 1995 with an additional sensor for atmospheric ozone research and is the current operational satellite. It continues to provide excellent data - far exceeding its nominal lifetime.

The PRoject for On-Board Autonomy (Proba) is a technology demonstration mission of the European Space Agency, The objectives of Proba are: in-orbit demonstration and evaluation of new hardware and software spacecraft technologies, onboard operational autonomy, and trial and demonstration of Earth observation and space environment instruments.