Session: 15-01-02: General Topics on Risk, Safety, and Reliability II

Paper Number: 164729

Risk Analysis of an In-Situ Resource Utilization System on Titan 

In 2022, NASA proposed a propellant harvesting system incorporating in-situ resource utilization (ISRU) on the Saturnian moon Titan for a future uncrewed mission. This system is intended to harvest the atmospheric gases and water ice present on Titan to produce sufficient fuel to power a sample return mission back to Earth. Propellant production is achieved through three separate subsystems: a methane harvesting system, a oxygen harvesting system, and a radioisotope thermal generator system. However, risk was not established for this system, despite the high-risk nature of even uncrewed spaceflight. In this paper, we present a preliminary risk assessment of an example mission to Titan focusing on the ISRU propellant production system. A review of the system is performed, which highlights the key components necessary for propellant production. Potential risks to mission failure are found and allocated to specific risk codes. A preliminary failure modes and effects analysis (FMEA) paired with a fault tree analysis utilizing a simple exponential model were used to analyze the system. A master equipment list (MEL) drawn from original technical specifications and mean time to failure data was found through a comprehensive literature review. The failure modes and effects analysis found that controller failures and over-pressurization risks were of high concern. Other failure concerns were found, such as the failure of key components in the oxygen harvesting system or fouling of critical heat exchange components. However, these risks were deemed to be moderate or low risk and are likely to be remedied during more advanced/detailed system development. The fault tree analysis determined that while the system did have a mean time to failure greater than the mission time proposed, the probability of a component failure was unacceptably high. Namely, failures in the oxygen harvesting system and the radioisotopic power subsystem were found to be the key point of failure for the system. To connect this analysis to actionable results, we provide an assessment of the components that contribute the most to overall system risk as well as key points to improve viability of these components. We also provide drawbacks of the analysis conducted as to provide starting points for improvement of the analysis provided. These include utilizing other risk assessment techniques and models, including a wider selection of risks, and sourcing failure data from Titanian conditions instead from lab conditions. Finally, other advances in Titan exploration are shown as well as in-situ resource utilization developments.

Presenting Author: Benjamin Sosa Colorado State University

Presenting Author Biography: Benjamin Sosa is a graduate student at Colorado State University. His research is focused on risk and reliability analysis of space in-situ resource utilization systems. He received his bachelor's degree in chemical engineering in August 2024 and is currently pursuing a masters of science in systems engineering.

Authors:

Benjamin Sosa Colorado State University
Vincent Paglioni Colorado State University