No abstract

The collision between the exhaust from the Primary Reaction Control System (PRCS) engines (870 pounds thrust) of the space shuttle and the ambient atmosphere has been observed from the Air Force Maui Optical Station (AMOS). Spectra have been obtained in the wavelength region near 630 nm. The temporal, spatial, and spectral distribution of the emission in this region has been recorded. The results reported here indicate that when the exhaust of the space shuttle interacts with the atmosphere in the ram direction, an intense, long-lasting emission at 630 nm due to O(1D --> 3p) is generated. A substantial amount of O(1D) is swept back onto the orbiter. Two processes are proposed for the formation of O(1D): (1) excitation of atmospheric O(3p) by collisions with the exhaust of the space shuttle engines; and (2) charge exchange between ambient O + and exhaust H20. Calculations using the SOCRATES code show excellent agreement with the data. 19,501

The gaseous and surface impact‐excited ultraviolet, visible, and infrared emissions that would result from plasma interactions near the windward directed surfaces of satellites orbiting in the earth's F region are reviewed. No process in the electrical discharge that would produce the intense orange‐red component of the glows seen on space shuttle and Atmospheric Explorer vehicles is identified. Spectroscopic and spatial‐distribution measurements to determine the contribution to the excitation of the collisionlessly energized suprathermal electrons and ions are suggested.

Ground‐based video photography of firings of Space Shuttle Primary Reaction Control System (PRCS) engines show optical emissions extending nearly 4 km from the vehicle after steady state is reached. The total intensity and spatial distribution of these emissions depend on the angle between the spacecraft velocity vector and the engine exhaust axis. Candidate sources for this radiation are reviewed and the conclusion is reached that it is most likely due to vibrationally excited OH, formed by the reaction of fast ambient O atoms and H2O molecules in the exhaust.

No abstract