Mission Analysis for the First-Ever Saturn Trojan 2019 UO$_{14}$

Abstract

In mid-2024, asteroid 2019 UO$_{14}$ was identified as the first-ever Saturn Trojan through ground-based archival observations and numerical simulations. Trojans, including those associated with Jupiter and other planets, raise important questions about the formation processes of our solar system. Exploring this Trojan object with spacecraft may provide direct answers and definitive evidence regarding these questions. This paper thoroughly investigates potential mission scenarios to the first Saturn Trojan, 2019 UO$_{14}$, to determine the necessary launch window and spacecraft specifications. First, by assuming a ballistic flight using chemical engines, optimal sequences of events, including (powered) gravity-assist maneuvers and deep-space maneuvers, are identified through a meta-heuristic global trajectory optimization algorithm. The analysis indicates that flyby exploration is feasible with a launch window around 2034 and a $\Delta V$ ranging from 92 m/s to 1041 m/s within an 11-year mission duration, while a rendezvous can be achieved with a departure around 2035 and a $\Delta V$ of 2-3 km/s. Specifically, the itinerary via Saturn requires a $\Delta V$ of 2 km/s and a flight time of 24.6 years, while the route via Jupiter results in a $\Delta V$ of 3 km/s and a flight time of 13.4 years. Given that the orbital motion of outer solar system objects is relatively slow, low-thrust propulsion, which gradually accelerates the spacecraft, proves to be effective. Consequently, low-thrust trajectories to 2019 UO$_{14}$ were examined. The results demonstrate that a rendezvous can be accomplished with nearly the same departure epoch, time of flight, and $\Delta V$ as in the ballistic flight, suggesting that low-thrust propulsion is highly compatible with the rendezvous scenario, as it significantly reduces the propellant mass fraction.