ESA has been dedicated to observing Earth from space ever since the launch of its first Meteosat meteorological satellite in 1977. Following the success of this first mission, the subsequent series of Meteosat satellites, ERS-1, ERS-2 and Envisat have provided us with a wealth of valuable data about Earth, its climate and changing environment.

It is crucial, however, that we continue to learn more about our planet if we are to understand the Earth system and its processes, especially within the context of global change. This will equip us better for predicting the effects a changing climate may bring.

As our quest for knowledge continues to grow, so does our demand for accurate satellite data to be used for numerous practical applications for protecting and securing the environment.

Responding to these needs, ESA's Living Planet Programme comprises a science and research element, which includes the Earth Explorer missions, and an Earth Watch element, which is designed to facilitate the delivery of Earth observation data for use in operational services.

Earth Watch includes the well-established meteorological missions with the European Organisation for the Exploitation of Meteorological Satellites (Eumetsat).

In addition, the GMES (Global Monitoring for Environment and Security) Sentinel missions, which form part of the GMES Space Component, will collect robust, long-term climate-relevant datasets. Together with other satellites, their combined data archives will be used to produce Essential Climate Variables for climate monitoring, modelling and prediction.

The Earth Explorer missions are designed to address key scientific challenges identified by the science community whilst demonstrating breakthrough technology in observing techniques. Involving the science community right from the beginning in the definition of new missions and introducing a peer-reviewed selection process ensures that a resulting mission is developed efficiently and provides the exact data required by the user.

This approach also gives Europe an excellent opportunity for international cooperation, both within the wide scientific domain and also in the technological development of new missions.

The family of Earth Explorer missions is a result of this strategy.

Currently, there are six missions in this category and a further five undergoing feasibility study.

GOCE: ESA's gravity mission
Launched on 17 March 2009, the Gravity field and steady-state Ocean Circulation Explorer (GOCE) mission is proving the dataset required to accurately determine global and regional models of Earth's gravity and geoid. It will advance research in areas of ocean circulation, physics of Earth's interior, geodesy and surveying, and sea-level change.

SMOS: ESA's water mission
Launched on 2 November 2009, the Soil Moisture and Ocean Salinity (SMOS) mission is making global observations of soil moisture and ocean salinity. By consistently mapping these two variables, SMOS is advancing our understanding of the exchange processes between Earth's surface and atmosphere and helping to improve weather and climate models.

CryoSat: ESA's ice mission
Launched on 8 April 2010, the CryoSat mission is monitoring centimetre-scale changes in the thickness of ice floating in the oceans and in the thickness of the vast ice sheets that blanket Greenland and Antarctica. Together with satellite information on ice extent, these measurements will show how the volume of Earth's ice is changing and lead to a better understanding of teh relationship between ice and climate.

Swarm: ESA's magnetic field mission
Due to be launched in 2013, Swarm is a constellation of three satellites to measure precisely the magnetic signals that stem from the magnetosphere, ionosphere, Earth's core, mantle, crust and the oceans. This sampling, in both space and time, will lead to an improved understanding of the processes that drive Earth's 'dynamo', which appears to be weakening.

ADM-Aeolus: ESA's wind mission
Due for launch in 2015, the Atmospheric Dynamics Mission (ADM-Aeolus) will make novel advances in global wind-profile observation and will provide much-needed information to improve weather forecasting. Aeolus is seen as a mission that will pave the way for future operational meteorological satellites dedicated to measuring Earth's wind fields.

EarthCARE: ESA's cloud and aerosol mission
Due for launch 2015, the Earth Clouds Aerosols and Radiation Explorer (EarthCARE) mission is a joint European-Japanese mission to improve the representation and understanding of Earth's radiative balance in climate and numerical weather forecast models.

Future Earth Explorers
Earth Explorer 7: Following ESA's Call for Ideas for the seventh Earth Explorer in 2005 and the subsequent selection in 2009, three missions – Biomass, CoReH2O and PREMIER are undergoing the next stage of development (feasibility study).

Earth Explorer 8: As a result of the Call for Proposals for the eighth Earth Explorer released in October 2009, the Florescence Explorer (FLEX) and CarbonSat missions have been approved to move forward to Phase A/B1. Approval was given by ESA's Earth Observation Programme Board on 24 November 2010.

Sentinel-1

Sentinel missions
ESA is developing a suite of new mission families called Sentinels, which aim to serve both the observational needs of the European GMES initiative, as well as broader requirements for climate monitoring and prediction.

The five Sentinel families include: the C-band radar Sentinel-1 mission for land and ocean services; the high-resolution optical imaging Sentinel-2 mission for land services; Sentinel-3 carrying an altimeter, optical and infrared radiometers for ocean and global land monitoring; Sentinel-5 Precursor, Sentinel-4 and Sentinel-5 for atmospheric composition monitoring from geostationary and polar orbits, respectively.

Meteosat
The Meteosat Third Generation (MTG) will take the relay in 2017 from Meteosat 11, the last of a series of four Meteosat Second Generation (MSG) satellites. This is a joint project between ESA and Eumetsat following the success of the first generation Meteosat satellites. The first of four MSG satellites was launched in 2002, entering into service with Eumetsat in early 2004 as Meteosat-8. The second MSG satellite, renamed Meteosat-9, was launched in December 2005. MSG-3 was launched on 5 July 2012.

MetOp

MetOp
Developed and procured by ESA, MetOp is a series of three satellites dedicated to operational meteorology until at least 2020. The programme, which forms the space segment of Eumetsat's Polar System (EPS), is Europe' contribution to a cooperative venture with the US, providing data to monitor climate and improve weather forecasting.

The first in the series, MetOp-A, was launched in 2006 and MetOp-B was launched on 17 September 2012. Preparations have also started for MetOp Second Generation or 'Post-EPS', the next step for the Eumetsat Polar System.

Data into services
Turning data into operational services requires that long-term relationships are developed between research institutes, service organisations and user communities.

ESA's Data User Element (DUE) aims to raise awareness with respect to the applicability of Earth observation in day-to-day operations. ESA's Value Adding Element (VAE), which builds on results of its precursor Earth Observation Market Development (EOMD) programme, complements the DUE by providing the framework for organising service chains capable of leveraging Earth observation data into commercial tools.