July 13, 2025 D. Arnas, R. Linares “Approximate Analytical Solution to the Zonal Harmonics Problem Using Koopman Operator Theory” Journal of Guidance Control and Dynamics [07315090] 44.11 (2021): 1909-1923. Print. Share this 44.11 (2021): 1909-1923. Print."] Related Stories See all news Supporting mission-driven space innovation, for Earth and beyond Nicole McGaa earns NSF Graduate Research Fellowship for bioastronautics research See all news