Trajectory Options and Feasible Entry Latitudes for a Saturn Probe Mission

The composition of outer planet atmospheres holds fundamental clues in understanding the process of the formation and evolution of the solar system. Measurements of noble gas abundances and key isotope ratios provide constraints to formation models, and along with measurements of atmospheric structure and dynamics they reveal evolutionary processes. These enable conclusions about giant planet formation and possible migration during the epoch of solar system formation. With the Galileo Probe laying the foundation of in-situ atmospheric measurements of the outer planets by probing Jupiter, entry probe missions to Saturn, Uranus and Neptune are essential to complete the picture of why and how our solar system came to its present state.

In this presentation, we focus on the target body Saturn with an eye to New Frontiers mission concepts for the upcoming new cycle. We present a statistical analysis of launch opportunities and associated trajectory options as a result of for a probe mission with a direct probe entry from interplanetary approach, enabling assessment of the options’ ramifications for science investigations and engineering. Based on the options examined, feasible entry latitudes are presented. The range of entry parameters such as relative entry velocity and the flight path angle is mapped to specific latitude ranges to give an overview on the impact of the entry site on the mission design, using the tool VAPRE (Visualization of Atmospheric PRobe Entry). A comparable presentation on Ice Giants will be given in December at the virtual AGU Fall Meeting 2020.

The presented research has been developed within the framework of a two- to three-year research study called IPED (Impact of the Probe Entry zone on the trajectory and probe Design. IPED investigates the impact of the interplanetary and approach trajectories on the feasible range of entry sites as well as the probe design, considering Saturn, Uranus and Neptune as target bodies. It was supported by an appointment to the NASA Postdoctoral Program (NPP) at the Jet Propulsion Laboratory (JPL), California Institute of Technology, administered by Universities Space Research Association (USRA) under contract with National Aeronautics and Space Association (NASA).