Optimal drag-energy entry guidance via pseudospectral convex optimization

In this paper a new drag-energy scheme for atmospheric entry guidance, based on the use of pseudospectral methods and convex optimization, is proposed. One of the most successful technologies to deal with atmospheric entry is the class of drag-tracking schemes, a direct heritage of the Space Shuttle program. The method that we propose exploits the drag-dynamics, and allows for an efficient automatic design of an optimal entry profile satisfying all the longitudinal constraints acting on the vehicle. A new representation of the entry-guidance problem, able to loss-less convexify the formulation, is provided. Numerical simulations confirm the validity of the proposed scheme as tool for further improving the autonomy of modern entry guidance systems, with a mean final range-to-go error at the end of entry phase smaller than 2 km, and the capability to re-compute a complete constrained trajectory to meet the mission requirements.