Europe’s space Sentinels
Based on over 30 years of experience in flying Earth observation satellites, ESA is developing five new types of spacecraft, known as Sentinels. Each Sentinel mission is made up of two satellites to ensure maximum Earth coverage.
These eyes in the sky will send back huge amounts of data about the Earth’s surface and atmosphere. This information will be used by Europe’s Global Monitoring for Environment and Security (GMES) programme.
Sentinel-1 is an all-weather, day-and-night radar imaging mission. Its many tasks will include monitoring of Arctic sea ice, checking for marine pollution (such as oil spills), mapping of land movements, studying forests, water and soil, and supporting disaster relief. The polar-orbiting Sentinel-1A satellite was launched on 3 April 2014.
Sentinel-2 is another pair of polar-orbiting satellites. They will provide detailed optical images of vegetation, soil and water cover, as well as coastal areas. The first Sentinel-2 satellite is planned for launch in 2015.
Sentinel-3 will carry several instruments to measure sea surface height, land and sea surface temperature, and ocean colour (created by tiny living creatures). Sentinel-3A should be launched in 2015.
Sentinel-4 and Sentinel-5 will both monitor air quality, the ozone layer, solar radiation and climate change. Sentinel-4 will consist of several instruments on board two Meteosat Third Generation weather satellites in orbit above the equator. The first Sentinel-4 payload is expected to launch in 2017.
The Sentinel-5 instruments will be carried on a polar orbiting MetOp Second Generation (MSG) satellite, flying at a much lower altitude than Sentinel-4. The launch of the first MSG is expected in 2019.