Measurements of ultraviolet radiation from a 5-km/s bow shock

Ultraviolet emission from a 5.1-km/s re-entry bow shock was measured in a sounding rocket experiment launched from the Barking Sands Research Range (Kauai, Hawaii) in February 1991 at 14:30 GMT. Optical data were obtained on the downleg portion of the flight as the payload descended from 115 to 62 km in a very shallow trajectory at a nearly constant speed. The intensity of the ultraviolet spectrum (A200-400 nm), and the vacuum ultraviolet resonance radiation emitted by atomic oxygen and hydrogen at A130.4 nm and À121.5 nm, respectively, were measured. Data from optical instruments in the 200-400-nm spectral region is presented here. Langmuir probe measurements provided data on the total plasma density and electron temperature in the boundary layer over a limited altitude range.