The European Space Agency (ESA) is preparing candidates for the next Earth Explorer Core mission with the aim to select the 7th Earth Explorer mission to be launched towards the end of this decade. Earth Explorers are the backbone of the science and research element of ESA's Living Planet Programme, providing an important contribution to the global endeavor of understanding the Earth's system, particularly in view of global climate change. Six candidate missions were selected and investigated in the preliminary feasibility studies (Phase 0). A further down-selection was made after the User Consultation Meeting held in Lisbon, Portugal, in January 2009. Three candidate missions (Biomass, CoReH2O and PREMIER) were selected for further feasibility investigations (phase A). Each of the candidate missions has been defined in detail through two parallel and competing industrial studies and many complementary science and technology studies, aiming to the final down-selection in 2013, followed by the mission implementation with a planned launch in 2019. This paper will give an overview of the observation requirements, satellite system, payload and general status of the Biomass mission.