Additive Manufacturing with Hypothesized Surface Materials – Regolith-Polymer Composites
INSTITUTION
Oregon State University (OSU)
CLASS
Platinum Class (2025 – 2026)
STUDENT TEAM
ACADEMIC GUIDANCE
PROJECT DESCRIPTION
This project investigated the feasibility of producing regolith-rich composite surface infrastructure applications on the asteroid Psyche, such as walkways, landing pad surfaces, and equipment staging areas. The work focused on maximizing the use of Psyche’s regolith as aggregate within a polymer binder matrix with the objective of achieving the highest possible regolith weight percent fraction while preserving structural integrity, dimensional stability, and mechanical performance under Psyche-relevant conditions.
Future missions to small asteroid bodies will require surface infrastructure that can be deployed with minimal imported mass while remaining mechanically reliable in a low-gravity environment. In-situ resource utilisation (ISRU) strategies offer a potential solution by incorporating locally available regolith into structural materials. This study investigated the feasibility of producing regolith-rich composite surface tiles for modular infrastructure applications, including walkways, landing pad surfaces and equipment staging areas. The primary objective was to maximise the incorporation of locally sourced regolith as aggregate within a polymer binder matrix. The objective is to achieve the highest possible regolith loading while maintaining structural integrity, dimensional stability, and acceptable mechanical performance under thermal cycling and low-gravity.
Composite samples were fabricated using a cast-and-cure process designed to approximate low-pressure manufacturing conditions that could realistically be adapted for extraterrestrial construction. Cylindrical pucks and square tile samples were fabricated using a cast-and-cure consolidation approach, with thermal and pressure-assisted processing applied when feasible. Two polymer binder systems, a toughened epoxy and an anhydride-cured epoxy, were evaluated in parallel due to their differing viscosity, curing characteristics, temperature resistance, and fracture resistance. Regolith loading was varied between 50 wt% and 80 wt% in increments of 10 wt% in order to determine the maximum viable filler fraction that could be achieved without severe processing defects. The limiting regolith content for each formulation was defined by the onset of excessive shrinkage, warpage, cracking, poor particle wetting, or loss of viable mechanical properties.
Based on observations from the initial puck samples, the most promising regolith loading compositions were selected for Phase 2 tile fabrication and mechanical testing. Mechanical performance was evaluated through tensile testing and three-point bending experiments to determine stiffness, strength and deformation behaviour. In addition, optical microscopy was used to analyse polished cross-sections of the composite samples in order to assess particle dispersion, binder wetting behaviour, and the presence of voids or microstructural defects. Surfactant additives were also evaluated as a processing variable to improve particle wetting and suspension of regolith within the polymer matrix. Samples produced with surfactants generally showed improved particle dispersion and reduced clustering compared to those produced without surfactants, indicating that wetting agents can play an important role in achieving uniform composite microstructures and high regolith loadings.
Results indicated that regolith loading significantly influences mechanical response and microstructural characteristics. Compositions with approximately 70 wt% regolith demonstrated higher stiffness and greater load-bearing capability, while 80 wt% regolith samples exhibited increased strain capacity but reduced strength. Microscopy observations revealed that the toughened epoxy binder provided improved particle wetting and more uniform dispersion of regolith particles wetting and more uniform dispersion of regolith particles within the composite matrix. In contrast, the anhydride-cured epoxy showed more pronounced particle clustering and settling during curing, which corresponded with reduced structural consistency in some samples.
The findings suggest that regolith loadings between 70 wt% and 75 wt% provide a practical balance between maximising the use of in-situ material and maintaining acceptable mechanical performance. These results contribute to the growing body of research on ISRU-enabled construction and provide an experimental framework for future development of regolith-based composite infrastructure for asteroid surface operations.
