Simulation Study of the Completion Time of the Endurance Mission

We study the reliability engineering of the proposed Endurance lunar rover. The goal of this study is to estimate the probability distribution of the rover's mission completion time using a simulation model, which must take into account the parameters that have a significant impact on mission time. We discovered three key components that have a significant impact on mission completion time: the mission plan, communications with earth, and rover mobility, from closely reviewing similar missions, such as the Curiosity and Perseverance rover expeditions on Mars. The Endurance mission will explore the moon's South Pole Aitken Basin (SPA), a large bombardment zone developed during the early phases of solar system formation, which is full of interesting features but contains some of the harshest terrain in the solar system. Temperatures can range from -232°C to over 130°C; there are areas of the crater sunlight does not penetrate. The rover's communication window has a 6-day blackout period per 28 days. Quantifying the impact of such factors on mission duration is critical. We provide a summary of how we modeled the rover's critical subsystems, the simulator technology used, and all of the as-sumptions we made while modeling the subsystem. Key results from the sensitivity analysis of over an order of magnitude range of mobility fault rates include: • The range of simulated mission durations at any given fault rate is 3–4 months, with small positive dependence on the rate; • The critical value of the fault rate for 90% probability of mission completion in 4 years is about 0.24x the rate experienced in Curiosity/Perseverance operations, with tail risk of 99 % completion within another month; • At that fault rate, we expect 1/3 of mission time to be spent recovering from fault, with 10% (absolute) potentially recoverable if additional backup satellite communications is provided; and • The range of arrival times to sampling sites is roughly a week, implying the concept of adaptively controlling other scientific stops to ensure arrival just before the lunar dawn is feasible.