Trajectory Optimization of Reentry Capsule

Reentry vehicles are required to meet stringent boundary conditions and path constraints, while minimizing certain cost functional. Parameter optimal control is easier and faster to solve than indirect methods for complex problems, such as the problem of re-entry trajectory optimization subject to multiple path constraints. In this paper, a direct transcription method is applied for finding optimal trajectory of 2 problems. Firstly, Newtonian method is used for finding aerodynamic coefficients of blunt nose conical re-entry capsule in hypersonic regime. Using these coefficients, trajectory satisfying path constraints corresponding to heat influx, G-load and control angles is generated while minimizing the vehicle manoeuvres. In the second problem Apollo capsule's multiphase optimization problem is solved based on the aerodynamic coefficients obtained from wind tunnel test data.