Vacuum Ultraviolet Spectral Measurements for Superorbital Earth Entry in X2 Expansion Tube

Experiments were conducted using the X2 expansion tube at two conditions representative of flight velocities of 10.0 km/s and 12.2 km/s for a vehicle entry into Earth's atmosphere. Calibrated spectral measurements were made of radiating shock layers across and through the surface of a model. These measurements provide a unique dataset for the validation of computational codes used in the calculation of incident VUV radiative heat flux. Computational simulations at equilibrium gas chemistry were conducted using the Specair program and showed good agreement with the measurements.