An Explicit Guidance Method for a Lifting Interplanetary Re-Entry Vehicle

Abstract

Future long-term plans for the robotic or human exploration of solar system bodies demand new and innovative concepts for the design of vehicles which can enter a planetary atmosphere and land on its surface safely. There has been and continues to be, considerable interest and research into the development of new trajectory generators and guidance systems for aerospace vehicles. Vehicle approaching a planet at hyperbolic speed passes through its atmosphere with very high thermal and mechanical loads. Vehicle and mission design process requires a thorough investigation of this flight phase and its sensitivity to environmental influences and uncertainties as well as vehicle properties. This report describes a guidance scheme combining onboard flight path prediction and optimization utilizing non-linear programming techniques. The optimization program makes use of a complex optimization method to find an optimized set of control parameters for a prescribed cost function and restrictions only once at the beginning of a mission phase, whereas the guidance program makes use of a simplified and fast method of Gradient Projection Algorithm (GPA) in order to have less computation load onboard.