Long-duration space missions critically depend on the cognitive performance of the crew. The physical effects of spaceflight are known for decades. Adverse cognitive effects have been reported (Takács et al., 2021; Pusil et al. 2023), highlighting the need for further investigation and close monitoring. Despite the findings, EEG was - and still is - an underutilized tool in spaceflight. Recent advances in electronics and sensors have further increased the versatility of EEG, supporting highly mobile recordings with high spatial and temporal resolution, rendering EEG suitable for future neuroscientific real-time in-flight brain monitoring.

We provide an introductory brief review of the most recent findings of in-flight EEG and compare the signal characteristics of spaceflight and on-earth EEG recordings. We analyzed resting-state EEG for conditions prior, during, and post spaceflight using previously published data (Cebolla et al., 2016). We compared the power spectral densities (PSD) between recordings performed on earth using the same device, and EEG systems with active shielding noise reduction (asalab and eego systems, ANT Neuro). We include both gel-based and dry electrode data (Fiedler et al. 2022).

Our results show that no increased noise level is evident for the EEG recordings during spaceflight, compared to recordings on earth. Differences in PSD levels are below the within-condition standard deviation. Using EEG devices with interference reduction by active shielding (asalab and eego), the spectral power of the on-earth recordings is in the order of magnitude of the in-flight recordings. The comparison of gel-based and dry recordings provides evidence for equivalent signal characteristics, underlining the potential of dry electrodes for EEG monitoring during long-term spaceflight missions.

We conclude that EEG recordings are an important and versatile tool for neuromonitoring during spaceflight. In-flight recordings may further profit from the use of state-of-the-art noise reduction electronics and easy to apply, gel-free dry electrode technology.