Observatory

OCO-2 flies in a near-polar, sun-synchronous orbit, enabling it to observe most of Earth's surface at least once every sixteen days and to measure carbon dioxide and solar induced fluorescence over a given location at the same local mean solar time on each pass.

To maximize science return, the Observatory collects data in three modes. In Nadir Mode, the instrument looks straight down at the surface below the spacecraft. In Glint Mode, it tracks the point of direct solar reflection off Earth's surface, a geometry that is especially effective over the ocean, where reflected sunlight yields highly accurate retrievals. In Target Mode, the instrument stares at a fixed surface site as the satellite passes overhead, enabling direct comparison with ground-based instruments such as those in the Total Carbon Column Observing Network (TCCON) and airborne campaigns used to calibrate and validate OCO-2 data.