[en] The authors report on a quenching rate determination for O(¹D) by O(³P), done by means of photometer and plasma probe data from a rocket borne experiment. Oxygen emission at 630 and 557 nm plays a major role in modeling space plasma effects. These states are created by dissociative recombination of O₂⁺. It was recently observed that the reaction of O(¹D) and O(³P) is an important rate for the deactivation process contributing to the 630 nm nightglow emission. The experiment measured 630 nm emission and electron density, and model neutral constituents concentrations, and then fit a rate constant to the input data