Vacuum-Ultraviolet Spectroscopy for Shock Layer Radiation Measurement

Abstract

The shock layer radiation in VUV and UV region is significant for the assessment of heat flux around the reentry vehicles with reentry velocity above 8km/s. To investigate the shock layer radiation in VUV region, the measurement system for vacuum-ultraviolet spectroscopy is newly developed. First, to deduce the absolute intensity from the measured spectrum, the calibration for the measurement system is conducted using the deuterium lamp which has a known absolute intensity. Second, the shock layer radiation measurement in VUV and UV region is conduction in two experimental conditions based on the lunar reentry trajectory. From these results, the atomic line spectra are predominant in VUV region. Whereas, the molecular band spectra is predominant in UV region. Furthermore, the radiation intensity in VUV region become more intense than that in UV region with increasing the shock velocity.