A class of mechanisms is presented which could give rise to the observed glow above Shuttle surfaces exposed to energetic collisions with ambient atmospheric constituents as the Shuttle sweeps through its orbit. The collisional energies involved are sufficient to dissociate atmospheric N2 upon impact with the Shuttle surfaces. The N-atoms formed can recombine on or over the surfaces to produce high vibrational levels of the N2 A(3&Sgr;u+) electronic state. At Shuttle altitudes, collisional quenching is negligible and the metastable N2(A, high v) molecules slowly radiatively decay to form N2 B(3&Pgr;g) molecules on a millisecond time scale. The B state molecules then rapidly radiate to the A state producing the red N2 First Positive Bands. This mechanism can explain both the spatial and spectral distributions of the observed glow. |