ESA consults European science community on candidate Earth Explorer missions   Earth Explorers   EarthCARE (Earth Clouds, Aerosols and Radiation Explorer) is an Earth Explorer Core Mission candidate. It is a joint Japanese-European proposal addressing the interaction and impact of clouds and aerosols on the Earth's radiative budget   An artist's impression of Spectra   WALES (Water vApour and Lidar Experiment in Space) is an Earth Explorer Core Mission candidate. WALES aims to provide a better understanding of the distribution of atmospheric water vapour in the troposphere and lower stratosphere.   ACE+ (Atmosphere and Climate Explorer) is an Earth Explorer Opportunity Mission candidate. ACE+ aims to to establish highly accurate and vertically resolved climatologies of humidity in the troposphere and of temperature in both the free troposphere and the stratosphere.   EGPM (European contribution to the Global Precipitation Monitoring (GPM) mission) is an Earth Explorer Opportunity Mission candidate. GPM aims to deliver global precipitation fields every 3 hours. EGPM will satisfy an integral component of the GPM constellation.   Swarm is an Earth Explorer Opportunity Mission. The Swarm constellation will study the dynamics of the Earth's magnetic field and its interactions with the Earth system. Each Swarm satellite will be eight metres long and weigh 300 - 400 kilograms. Release date: 22 April 2005