The first measurements of the spectral flux on a horizontal surface, limb brightness and apparent surface brightness beneath the NASA ER‐2 research aircraft were made during the Stratospheric Photochemistry, Aerosol and Dynamics Expedition (SPADE) of the NASA High‐Speed Research Program. Results from the May, 1993 campaign are presented. J‐values for the production of O(¹D) from the photodissociation of ozone and the photodissociation rate of NO₂ to form NO have been determined and are compared to the currently used, modelled values.