LAUSR

Abstract Saturn's largest moon, Titan, has seas of cryogenic liquid methane and ethane as well as dynamic geology and a cycle of methane evaporation and rain. NASA is evaluating concepts for an extraterrestrial submarine to explore these seas from surface to bottom to shoreline, representing an unprecedented design challenge. The Titan submarine ballast system that controls the vertical ascent and descent must operate autonomously for a minimum of 365 dives in cryogenic seas below 95 K and handle liquid density variations up to 30%. Further complicating the concept is the high solubility of nitrogen gas in the seas, which leads to potential phase change and boiling issues during ballast pressure control. This paper presents a trade study of 7 advanced concepts for an autonomous submarine ballast system for Titan; 4 were down-selected as viable concepts. For each concept, analytical system description and sizing, autonomous concept of operation, parts list, and pros and cons are given. Systems are traded using mass, power, and complexity in control as metrics.