GOSAT (Greenhouse gases Observing SATellite), nicknamed IBUKI, is an active JAXA-led Earth-observation program launched on 23 January 2009. Developed jointly by JAXA, Japan’s Ministry of the Environment, and the National Institute for Environmental Studies, it was designed specifically to monitor atmospheric carbon dioxide and methane globally, estimate regional greenhouse-gas sources and sinks, verify emissions reductions, and advance greenhouse-gas observation technology.