indirecpublic

This repository contains a JAX-based reference implementation for planar planetocentric circular-to-circular (C2C) solar-sail transfers, solved via indirect optimal control (single shooting). The dynamics are formulated in a polar coordinate system. The indirect Optimal Control Problem (OCP) is set up using the Calculus of Variations and Pontryagin's Maximum Principle. This principle allows the control input to be written as a function of the costates, for which the dynamics are derived from the objective function and the Hamiltonian. As a result, the problem is transformed into a finite-dimensional two-point boundary value problem (TPBVP). In this indirect problem formulation, only an initial guess of the costates and Lagrange multipliers is required. The resulting system is then solved using a single-shooting method. This solver framework is then applied to multiple-revolution planetocentric transfers to analyze optimal sail behavior and assess overall transfer performance.