Helical Anchors: Lateral Resistance for Shaping the Lunar Surface

Resistance to lateral forces will be critical to shaping the lunar surface on manned or robotic missions. The development of an efficient and stable regolith anchor will require significant research and experimentation prior to a lunar mission. This paper describes experimental research into the behavior of helical anchors as a function of depth, shaft size, and anchor plate diameter in the context of the lunar surface. Through the application of the principles of centrifuge modeling in soil mechanics, scaling effects and the difference between the earth-based model and the lunar prototype are rigorously accounted for. Using a crude lunar simulant, a series of experiments were undertaken to investigate varying installation parameters and their respective effects on anchor behavior. Soil test beds were compacted inside a containment bin using a plate compactor in multiple lifts in order to simulate a typical lunar surface condition. Anchors were then installed vertically and lateral loads were applied to them at the sample surface; measurements of horizontal and vertical displacements, and magnitude of the applied lateral load were made. These results can be used as a preliminary basis for designing screw-in anchors for use in various operations on the lunar surface.