GOSAT (Greenhouse gases Observing Satellite / Ibuki)

GOSAT (Greenhouse gases Observing Satellite), also known as Ibuki, is a joint mission of the Japan Aerospace Exploration Agency (JAXA), the Ministry of the Environment of Japan (MOE), and the National Institute for Environmental Studies (NIES), launched on 23 January 2009 into a sun-synchronous orbit at 666 km altitude (JAXA mission page gives 667 km) with a 3-day revisit cycle.^[1][2]

The primary instrument is TANSO-FTS (Thermal And Near infrared Sensor for carbon Observation - Fourier Transform Spectrometer), a four-band instrument spanning 0.76 to 15 micrometres with 10.5 km ground resolution and 0.012 nm spectral resolution at the O2-A band. GOSAT data demonstrated sun-induced chlorophyll fluorescence (SIF) retrievals at the 757 nm and 771 nm Fraunhofer lines. The spacecraft also carries TANSO-CAI, a cloud and aerosol imager supporting atmospheric correction.^[1][3]

GOSAT operated from 2009 to 2026. The TANSO-FTS entered a Light Load Mode event in March 2025 and data delivery was suspended in December 2025 due to instrument anomaly; science data delivery resumed in February 2026. The mission is operated jointly by JAXA, MOE, and NIES, with data distributed through the JAXA Earth Observation Research Center.^[3][4]