Shaking as means to detach adhered regolith for manned Phobos exploration

Recent work has shown that cohesion drives the behavior of surficial regolith grains up to centimeters in size on the surface of small planetary bodies such as asteroids. Mars' moon Phobos is similar in morphology and size to asteroids. Additionally, Phobos has been discussed as a possible target for human exploration, due to its relatively small gravity well. Dust adhering to spacesuits (and subsequently detaching in a pressurized spacecraft) was a source of concern during the Apollo era. We apply improved understanding of the forces active on regolith grains to compare their relative strength, showing that Phobian regolith up to millimeters in size is likely to be dominated by Van der Waals cohesion. Additionally, we show that astronauts will be unable to detach dust grains smaller than 1-100 μm that are adhered to their gloves through shaking alone, with the size range for detachment depending on the material properties of the regolith and spacesuit.