The process of spacecraft trajectory design frequently incorporates an optimization step in which one or more objectives, such as propellant consumption or time of flight, is minimized. Optimization is especially crucial for low-thrust mission design, due to the need to specify a thrust vector at every instant in time along a trajectory. At NASA's Goddard Space Flight Center (GSFC) a number of open-source tools have been developed for spacecraft trajectory optimization that utilize direct shooting and collocation methods. These tools have been effectively applied to cislunar, libration point, and interplanetary mission design for the Lunar IceCube, SWFO, and DAVINCI missions, among others. This presentation outlines the theory underlying these optimization tools along with the details of their application to several trajectory design problems, with a focus on the Lunar IceCube (LIC) mission. The LIC mission required a low-thrust trajectory from a high-energy deployment state to a lunar orbit, and its limited control authority necessitated the use of optimization tools and low-energy trajectory design techniques. The tools discussed demonstrate how the use of optimization methods expands mission capabilities and enables transformational science.
Robert Pritchett is an aerospace engineer in the Navigation and Mission Design Branch at NASA’s Goddard Space Flight Center. Before his time at Goddard Robert received his Bachelor of Science in aerospace engineering from The University of Texas at Austin, and a Masters and Doctorate in the same field from Purdue University. At Purdue, Robert researched strategies for low-thrust mission design in multi-body environments under the guidance of Professor Kathleen Howell. At Goddard, Robert currently supports mission design efforts for the Space Weather Follow On (SWFO) mission and was previously a member of the Lunar IceCube mission design team. Additionally, he contributes to several internal research and development projects with the goal of enhancing Goddard's trajectory optimization capabilities.
Event Date: April 27, 2023