Optimizing Trajectories for Unpowered Hypersonic Waveriders during Atmospheric Reentry

Over the years, many aerospace corporations and agencies have attempted to develop hypersonic vehicles. Until recently, they have achieved very limited success due to a lack of air-breathing hypersonic propulsion technology. Now, as technology is advancing and funds are becoming more available, aviation is once again shifting its focus towards hypersonic flight. One of many hypersonic applications is atmospheric reentry, whether reentry into Earth’s atmosphere or entry into another planetary body’s atmosphere. While basic theories on hypersonic reentry flight mechanics are already in use, these analyses have yet to be applied to optimizing trajectories for hypersonic waveriders in skip-glide atmospheric entry trajectories. The purpose of this research project was to provide a brief analysis of unpowered skip and glide entry trajectories and to present an optimized hypersonic waverider trajectory for a simple atmospheric reentry scenario. Five main types of unpowered glide trajectories—constant flight path angle, constant sinking speed, constant flight speed, constant dynamic pressure, and constant heating rate—were analyzed to model the altitude, velocity, flight path angle, and lift modulation profiles. Additionally, constant aerodynamic efficiency skip trajectories were analyzed for their ability to extend reentry ranges. The results of these analyses were then used to optimize a combined skip-glide atmospheric reentry trajectory for hypersonic waveriders about the Earth’s equator. The resulting trajectory maximizes the range of the reentry trajectory while conforming to applied maximum aerodynamic heating and maximum dynamic pressure constraints. This project also provides an update on current technology readiness levels for various atmospheric hypersonic propulsion systems that could potentially be used on a waverider. The findings of this research will benefit the aerospace community by providing insight into hypersonic waverider performance during Earth reentry after completed space missions. This information can be used to inform flight vehicle design decisions for optimizing hypersonic waverider performance. Moreover, beyond just Earth atmospheric reentry, the analyses used in this research can also be applied to atmospheric entry into other planetary atmospheres, aiding in vehicle design and planning for interplanetary missions.