Spectrally and Spatially Resolved Radiance Measurement in High-Speed Shock Waves for Planetary Entry

Three-dimensional images of absolute radiance as a function of position and wavelength are obtained for shock-heated plasmas traveling in a shock tube at velocities near Mach 30. Vacuum optics coupled to a shock tube are used to image the shock onto four separate spectrometers, which, in turn, disperse the radiation in wavelength onto intensified CCD arrays covering selected spectral ranges from the vacuum ultraviolet (>;120 nm) through midwave infrared (<;5000 nm). Quantitative radiometry performed in this fashion is used to benchmark radiative heating codes used in sizing spacecraft thermal protection systems.