Radiation Database for Earth and Mars Entry

This lecture presents the general guidelines we have followed to build up an exhaustive and accurate spectroscopic database for radiative transfer in air and CO2-N2 plasma applications, including atmospheric entries. This High Temperature Gas Radiation (HTGR) database includes bound-bound atomic, diatomic and polyatomic (in particular CO2) transitions, bound-free transitions resulting from various mechanisms, and free-free transitions. The covered spectral range is 1000–200,000 cm−1 and the targeted maximum temperature is 30,000 K. A particular attention is given to the selection of the most reliable fundamental data (line strengths for atoms and ions, electronic transition moment functions and spectroscopic constants for diatomic molecules, cross sections for continuum radiation), and to accurate prediction of atomic and ion line shapes which are strongly self-absorbed. The spectroscopic database is applied in the last part of this lecture to the simulation of Fire II experiment as an example of earth entry, and to the prediction of a Mars entry simulation. We discuss in these applications the spectral distribution of radiative fluxes from the infrared to the VUV, the effects of optical thicknesses and self-absorption, and the effects of chemical nonequilibrium on continuum radiation.