7239 20260109134041.0 10.1088/1755-1315/1522/1/012019 DOI SCART-2025-0016 Dewitte, Steven The Earth Climate Observatory space mission concept for the monitoring of the Earth Energy Imbalance 2025 We present the Earth Climate Observatory space mission concept - currently stud- ied in Phase 0 as a European Space Agency Earth Explorer 12 candidate - for the measurement of the Earth Energy Imbalance and the Earth Radiation Budget. Key innovations are 1) the differential Sun-Earth observation with identically constructed wide field of view radiometers, 2) an adequate sampling of the seasonal diurnal cycle with a constellation of polar precess- ing orbits, 3) complementary full angular coverage at high spatial resolution using wide field of view multispectral cameras. NO Earth Energy Imabalance Earth radiation Budget Mauritsen, Thorsten Meyssignac, Benoit August, Thomas Schifano, Luca Smeesters, Lien Roca, Rémy Brindley, Helen Russell, Jacqueline Clerbaux, Nicolas Hollmann, Rainer Megner, Linda Haberreiter, Margit Gumbel, Joerg Marotzke, Jochem Riedi, Jérôme Riihelä, Aku Trent, Tim Wendisch, Manfred IOP conference series Earth Environ. Sci. 1522 2025 012019 steven.dewitte@ksb-orb.be published in REFERD