Mitochondria form highly dynamic networks maintained by the balance of fission and fusion. These opposing processes are critical for preserving mitochondrial function during metabolic and environmental stress—fusion supports recovery through complementation, while fission enables biogenesis, quality control, and apoptosis under high stress. While mitochondrial dysfunction has been linked to astronaut fatigue, mood disorders, cognitive decline, and potentially linked to oxidative stress effects caused by microgravity, little is known about how static magnetic fields (SMFs) encountered in deep-space impact mitochondrial networks and the underlying fission and fusion processes. While space missions such as NASA’s Galileo at Jupiter (∼ 400 μT) and Parker Solar Probe near the solar corona (∼ 4,000 μT) report SMF strengths far outside Earth’s field (∼50 μT), their effects on human neuronal cell function, ATP production, or mitochondrial dynamics remain largely unexplored. Here, we investigated mitochondrial dynamics in human neuronal progenitor cells exposed to SMFs of 50 μT, 400 μT, and 4,000 μT over a 72-hour adjustment period. Cells were stained with MitoTracker Deep Red and live-imaged every 12 hours. Post-processing of false-color fluorescent images quantified mitochondrial fragmentation using a circularity index. Compared to Earth-normal conditions, both 400 μT and 4,000 μT magnetic field exposures resulted in a ∼20% increase in circularity index, indicating a trend toward mitochondrial fission and fragmentation. These findings suggest that deep-space magnetic fields may impact mitochondrial networks in neuronal progenitor cells, potentially impairing neuronal energy regulation during long-duration missions. Understanding such alterations will be essential for mitigating neurocognitive effects during human space exploration. Acknowledgments: this work was partially funded by the US National Science Foundation under Grant #2050856 and NASA EPSCORE R3 Award (#24-2024 R3-0114, RFA071).
Ramirez et al. (Sun,) studied this question.