ESA future earth observation explorer missions

A new call for Core Earth Explorer Ideas was released by the European Space Agency in March 2005. The Call focused on the global carbon and water cycles, atmospheric chemistry and climate, as well as the human element as a cross cutting issue. The proposals were peer reviewed by scientific panels, and also appraised technically and programmatically by ESA. This paper describes the Earth Explorer cycle and gives an overview of the six candidate missions selected for assessment studies.