Krzysztof Skonieczny

Additive manufacturing of PEEK/regolith composites offers a promising route for lunar in-space manufacturing by reducing dependence on Earth-supplied materials. However, the processability of these composites and the elastic response of printed components are strongly influenced by regolith loading and manufacturing-induced defects. This study develops a hierarchical finite element framework to quantify the stiffness of additively manufactured PEEK containing 10-50 wt% LMS-1D lunar regolith simulant and to distinguish intrinsic composition effects from defect-driven stiffness losses. The approach combines composition-based estimation of regolith properties with microstructure-informed simulations of PEEK/regolith composites. Under defect-free assumptions, the predicted modulus increases monotonically from 1.27 GPa at 10 wt% to 1.97 GPa at 50 wt%, showing good agreement with experimental trends up to 40 wt%, where deviations remain within 3.5-10.1%. At 50 wt%, however, the experimental modulus decreases to 1.27 GPa, while the defect-free model predicts 1.97 GPa. Microscopy-informed single-layer analyses indicate that tall crack-like interfacial voids, polymer-starved welds, and interconnected weak seams significantly reduce load transfer and shift the mechanical response toward an interface-controlled regime. These results show that regolith additions can enhance stiffness only until defect connectivity becomes dominant. The findings provide insight into the process-structure-property relationships governing ceramic particle-reinforced high-performance thermoplastics in additive manufacturing.

As humankind prepares to establish outposts and infrastructure on the Moon, the ability to manufacture parts and buildings on-site is crucial. While transporting raw materials from Earth can be costly and time-consuming, in-situ resource utilization (ISRU) presents an attractive alternative. This review paper aims to provide a thorough examination of the current state and future potential of Lunar-based manufacturing and construction (LBMC), with a particular focus on the prospect of utilizing in-situ resources and additive manufacturing. The paper analyzes existing research on LBMC from various perspectives, including different manufacturing techniques and compositions, the potential of ISRU for LBMC, characterization of built parts and structures, the role of energy sources and efficiency, the impact of low-gravity and vacuum conditions, and the feasibility of using artificial intelligence, automation, and robotics. By synthesizing these findings, this review offers valuable insights into the challenges and opportunities that lie ahead for LBMC.

This paper presents the energy-optimal trajectories for skid-steer rovers on hard ground, without obstacles. We obtain 29 trajectory structures that are sufficient to describe minimum-energy motion, which are enumerated and described geometrically; 28 of these structures are composed of sequences of circular arcs and straight lines; there is also a special structure called whirls consisting of different circular arcs. Our analysis identifies that the turns in the trajectory structures (aside from whirls) are all circular arcs of a particular turning radius, R′, the turning radius at which the inner wheels of a skid-steer rover are not commanded to turn. This work demonstrates its paramount importance in energy-optimal path planning. There has been a lack of analytical energy-optimal trajectory generation for skid-steer rovers, and we address this problem by a novel approach. The equivalency theorem presented in this work shows that all minimum-energy solutions follow the same path irrespective of velocity constraints that may or may not be imposed. This non-intuitive result stems from the fact that with this model of the system the total energy is fully parameterized by the geometry of the path alone. With this equivalency in mind, one can choose velocity constraints to enforce constant power consumption, thus transforming the energy-optimal problem into an equivalent time-optimal problem. Pontryagin’s Minimum Principle can then be used to solve the problem. Accordingly, the extremal paths are obtained and enumerated to find the minimum-energy path. Furthermore, our experimental results by using Husky UGV provide the experimental support for the equivalency theorem.