Pure rotation line emissions from highly rotationally excited OH have been observed between 80 and 110 km tangent height under both nighttime and daytime quiescent conditions. Data were obtained using the cryogenic CIRRIS 1A interferometer, operated on the Space Shuttle. Transitions from OH(v=0–2, N′≤33) were identified between 400 and 1000 cm−1, corresponding to states with energies as high as 23000 cm−1. These are the first definitive observations of OH pure rotation transitions in the air glow, and by far the highest N levels observed in any type of OH airglow emission spectrum. The present observations of highly excited rotational states of OH parallel those made during recent field studies of NO and laboratory studies of OH, NO, and CO.

Individual OH(ν,N) rotational state population column densities have been derived from spectral analysis of CIRRIS 1A nighttime earthlimb airglow data. Both pure rotation and vibration‐rotation fundamental spectra have been examined, providing unique information on highly excited rotational states of OH(ν=0‐6). The relative populations of the four spin sublevels have also been determined. These findings provide important insights into OH dynamics at the mesopause.

The analysis of CIRRIS 1A (Cryogenic InfraRed Radiance Instrumentation for Shuttle) interferometric and radiometric data obtained during the flight of STS‐39 (28 Apr–6 May 1991) reveals the presence of IR emission in the 400–900 cm−1 (11–25 μm) region not attributable to atmospheric emission. In this paper, data are shown which identify the signal as near‐field water vapor present during all CIRRIS 1A observations. Variability of the near‐field water vapor emissions is characterized, and further investigation indicates that the water is excited to high effective temperatures, possibly in excess of 2000 K. The data presented support the conclusion that water outgassed from the shuttle tiles is highly excited by collisions with atmospheric O, classifying it as a type of shuttle‐induced glow whose spectrum has never previously been measured in the LWIR. Measured results are compared to current models which predict radiance for collisionally excited outgassed molecules.

An artificial auroral experiment, Precede, was performed in the 80-to 120-km altitude range above the White Sands Missile Range, New Mexico, in October 1974. A 2-kW rocket-borne electron accelerator, square wave modulated at 0.5 Hz, was activated at 95 km on payload ascent, was pulsed continuously through apogee (120 km) to a descent altitude of approximately 80 km, and provided a total of 90 pulses of a 2.5-kV 0.8-A electron beam over a period of 180 s. A ground-based dual channel telephotometer recorded the time-dependent photon emission rate of the N2+(B22u + --, X22g + ) first negative (0-0) band at 3914 A• and the O(•S -• XD) transition at 5577 A• induced in the night atmosphere by the pulsed electron source. An electron-induced luminous efficiency of (4.5 + 0.4) X 10 -3 was determined for the N2 + IN (0-0) transition at 3914 A• in the 80-to 100-km altitude range. The photon emission rates of several bright stars were measured to calibrate the telephotometer and to correct for the effects of atmospheric extinction. The time-dependent O(xS) 5577-A• photon emission rate has been fitted with a model calculation providing insight into O(xS) production and loss processes resulting from the deposition of energetic electrons in the 90-to 116-km altitude range. At altitudes in excess of approximately 110 km the O(xS) time-dependent photon emission profiles indicate that consecutive reactions involving energy transfer from N2(A32u +) to O(3P) is the dominant O(•S) production process. A rate coefficient of 5.7 X 10 -x2 cm 3 s -x representing an O(xS) yield of 0.29 has been inferred from the data for the reaction of N2(A32u +) and O(3P). The dissociative recombination of 02 + has been established as the dominant O(xS) production process at altitudes less than 96 km with an O(xS) yield of 4.5-6.0% per dissociation. Other processes account for approximately 20% or less of the total O(xS) production at 90 km with smaller contributions indicated at higher altitudes. Collisional deactivation by O(3P) accounts for approximately 50% of the total O(xS) depopulation rate in the 95-to 116-km altitude range with a rate coefficient of 6.0 X 10 -n e -3ø•/r cm 3 s -•. Quenching by O2 dominates as an O(xS) loss mechanism at altitudes less than 94 km with an estimated rate coefficient of 1.2 X 10 -n e -8•ø/r cm 3 s -x. The rate coefficients determined for O(xS) produced by the reaction of N2(A32• +) and O and the collisional deactivation processes have a probable error of approximately 25% if it is assumed that the model atmosphere used in the analysis contributes no significant uncertainty. 407.41-1) instrumented with a 2-kW (2.5 kV, 0.8 A) electron accelerator launched at 1020:00 UT on October 17, 1974, from the White Sands Missile Range, New Mexico. The electron source, square wave modulated at 0.5 Hz, was initiated at 95 km on payload ascent and continued through apogee (120 km) to a descent altitude of approximately 80 km, operating for an interval of 180 s. Camera systems were located at three different ground-based optical site...

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