O(1S) 557.7 nm and O(1D) 630 nm emissions in shuttle thruster plumes

Radiation resulting from interaction between the effluent cloud of a space shuttle thruster and the ambient atmosphere was observed with a spectrograph aboard the shuttle. The spectral measurements were made between 400 and 800 nm with a resolution of 3 nm. The primary emissions are identified as NO2, HNO, O(1D), and O(1S). These are the first observations of O(1S) emission in the shuttle plume. These data are compared with previous measurements, and possible excitation mechanisms are discussed. The results are also compared with a Monte Carlo simulation of thruster plume-atmosphere interaction radiation.