Enhancing astronaut training: effects of transcranial direct current stimulation on manual rendezvous and docking...

Manned spaceflight missions are characterized by significant operational risks, low fault tolerance, and high complexity, necessitating astronauts to achieve exceptional proficiency through training. This study employed a double-blind, randomized, placebo-controlled design to investigate the effects of transcranial direct current stimulation (tDCS) on astronauts' acquisition of manual rendezvous and docking (RVD) skills. Additionally, electroencephalography (EEG) was utilized to analyze tDCS-induced cortical modulations during manual RVD training.

A total of 26 participants (tDCS group, n = 14; sham group, n = 12) completed the experiment. Each participant underwent eight blocks of manual RVD training, with EEG recordings throughout the training. A bilateral M1 montage (anode at C3, cathode at C4) was applied using 1.5 cm ring electrodes, with stimulation lasting 25 min over four training blocks. Learning outcomes for both groups were quantified using composite scores derived from endpoint accuracy parameters and performance metrics related to manual RVD training. Additionally, a skill retention test was administered three weeks after the completion of training.

The tDCS group demonstrated superior performance in skill acquisition compared to the sham group. Significant group × time interactions were observed in both RVD attitude accuracy (F = 2.606, p = 0.024, Cohen's d = 0.367) and composite performance scores (F = 2.506, p = 0.026, Cohen's d = 0.646), with the tDCS group exhibiting an average performance improvement of 11% over the sham group. Furthermore, retention tests administered three weeks post-training revealed significantly higher scores in the tDCS group (t = 2.874, p = 0.011, Cohen's d = 1.189). EEG analysis indicated distinct θ band activity patterns in the right M1 region between the two groups during training [F(1,50) = 5.910, p = 0.025, η² = 0.172], with the tDCS group showing characteristic neural modulation patterns that correlated with enhanced skill learning.

This study demonstrates that bilateral M1 tDCS enhances manual RVD skill acquisition in astronaut training. This technique shows promise for application in astronaut training, potentially improving the efficiency and retention of skill training for space missions.