Radiative contamination in rocket-borne infrared photometric measurements

In a rocket experiment designed to measure the infrared atmospheric system of the O2 and several OH Meinel bands in the Δυ = 2 sequence, an unexpected enhancement of the emission was observed on the upleg when the rocket reached an altitude of 92 km. The glow was detected only in the channels with larger half-power bandwidth, those devoted to the study of the OH emission. This enhancement is interpreted in terms of local contamination originating from interactions between the instrument and the atmosphere. On the basis of the spectral distribution of the radiative glow the contaminating agent is tentatively identified as vibrationally excited OH, and the proposed mechanisms giving rise to the glow are discussed.