Radiative Heat Transfer Measurements of Titan Atmospheric Entry in a Shock Tube

Abstract

Measurements were performed in the T6 Stalker facility operating in Aluminum Shock Tube mode for conditions relevant to Titan entry. Spatially and spectrally resolved radiation emitted from a high-temperature test gas behind a normal shock was recorded by means of emission spectroscopy. For Titan atmospheric entry, the main radiator of interest is cyano radical, formed in the nonequilibrium region behind the shock. The tests reported in this work measured radiation at velocities from 3.1 to 8.5 km/s and freestream pressures of 13, 20, and 133 Pa at a nominal composition of 98% [Formula: see text] and 2% [Formula: see text]. These shock layer radiation experiments employed an optical emission spectroscopy system on each side of the facility to allow two spectral regions to be measured simultaneously for each test, covering the spectral range of 200–900 nm. The present work provides a new, comprehensive benchmark set of data relevant to Titan entry studies.