The completed study investigated Martian regolith simulant composites’ material properties when there was variation in the type of used Martian regolith simulant. Four types of Martian regolith simulant were mixed at varying weight percent loadings with polypropylene using twin screw extrusion. Test parts were made via injection molding with all the polymeric composites, and additive manufacturing with select polymeric composites. ASTM standard based tests and ANOVA tests were completed to investigate material characteristics. Depending on the creation process, the results suggested that Martian regolith simulant type impacted several material characteristics. During material processing, a foaming behavior was observed with all the materials, especially material that used MGS-1S. Additive manufactured parts were found to be impacted by the foaming behavior. A literature based thermal breakdown study suggested that thermal releases from the Martian regolith simulants were the likely candidates for the foaming behavior.