Application and analysis of bounded-impulse trajectory models with analytic gradients

Bounded-impulse trajectory models are an important component of many spacecraft trajectory preliminary design workflows. This paper includes discussions on practical implementation considerations for establishing a numerically robust preliminary design optimization framework. Efficient computation of the mathematical components required to compute analytic gradients is discussed, and a guiding numerical example is provided for validation purposes. A solar electric power model suitable for preliminary mission design is presented, including a method for handling thruster cutoff events that result in nonsmooth derivatives. The challenges associated with incorporating the Spacecraft Planet Instrument C-Matrix Events high-fidelity ephemeris system into a trajectory optimization framework are discussed, and an alternative that results in smooth partial derivatives with respect to time is presented. Application problems that illustrate the benefits of employing analytic Jacobian calculations in favor of using the method of finite differences for both low- and high-thrust trajectory models are presented. The advantages of using an analytic Jacobian in a solver that combines the monotonic basin hopping heuristic method with a local gradient search are also explored.