Speaker
Description
Uranus and Neptune are the only two exemplars of ice giant planets in the Solar System. This planetary class is currently not well understood, as the models for their interior structure cannot be fully explained by observations. As opposed to planets classified as gas giants, ice giants are mainly composed of volatile substances heavier than hydrogen and helium, called \textit{ices}, in their bulk. Such unique composition suggests that their formation is rather a rare event, which contrasts with their abundance in our galaxy. An exploration of Neptune and Uranus, the ice giant planets of the Solar System, involves entries at high velocities into atmospheres consisting of H$_2$, He and CH$_4$. Experiments in plasma wind tunnels at the Institute of Space Systems of the University of Stuttgart have been conducted to investigate the behavior of this plasma. Two emission spectrometers were set up to characterize the free-stream plasma and optical filters were used to avoid the prominent H lines of the Balmer series. The final paper will present free-stream spectra measured in the wavelength range from 250 to 880 nm during experiments of ice giant entries. A series of optical filters will be used to block the most prominent H lines, which will allow for more detailed analyses of the CH and the C$_2$ molecular radiation in the plasma. In addition to the Echelle spectrometer used in the previous campaign, a second spectrometer will be set up to record emission spectra from 280 to 433 nm. To resolve the temperatures and number densities of the produced species, the spectra will be fitted to simulations
Summary
The exploration of Neptune and Uranus, the ice giant planets of the Solar System, involves entries at high velocities into atmospheres consisting of H2, He and CH4. Because these entries may produce radiative heat fluxes not yet fully understood, arcjet experiments to simulate them were conducted at the PWK1 facility of the Institute of Space Systems at the University of Stuttgart. Two emission spectrometers were set up to characterize the free-stream plasma and optical filters were used to avoid the prominent H lines of the Balmer series. The final paper will show a spectrum from 250 to 880 nm acquired during ice giant atmospheric entry experiments. Additionally, the measured spectra will be fitted to simulations to resolve the temperatures and number densities of the produced species.
