Global Search of Optimal Spacecraft Trajectories using Amortization and Deep Generative Models
This work addresses the computationally intensive global search for optimal spacecraft trajectories, offering a domain-specific improvement for aerospace engineering.
The paper tackles the global search problem in preliminary spacecraft trajectory optimization by learning a conditional probability distribution over solution basins using deep generative models, achieving significant speed-up over multi-start and vanilla machine learning methods in a low-thrust trajectory benchmark.
Preliminary spacecraft trajectory optimization is a parameter dependent global search problem that aims to provide a set of solutions that are of high quality and diverse. In the case of numerical solution, it is dependent on the original optimal control problem, the choice of a control transcription, and the behavior of a gradient based numerical solver. In this paper we formulate the parameterized global search problem as the task of sampling a conditional probability distribution with support on the neighborhoods of local basins of attraction to the high quality solutions. The conditional distribution is learned and represented using deep generative models that allow for prediction of how the local basins change as parameters vary. The approach is benchmarked on a low thrust spacecraft trajectory optimization problem in the circular restricted three-body problem, showing significant speed-up over a simple multi-start method and vanilla machine learning approaches. The paper also provides an in-depth analysis of the multi-modal funnel structure of a low-thrust spacecraft trajectory optimization problem.