Simulated landscapes of Mars have been made of thermoplastic sheets molded to shapes derived from images of the Martian terrain. These simulated landscapes can be used to advantage in scientific experiments, simulations, educational displays, and other applications, in which unitary molded plastic sheets can be handled more easily and pose less risk of contamination than do simulated landscapes made of loose rocks. Fabrication begins with the selection of terrestrial rocks with a distribution of sizes and textures representative of the terrain of interest. The rocks are arranged on the vacuum table of a thermoforming apparatus. A sheet of thermoplastic material (e.g., polycarbonate 1.58 mm thick) is heated to drive off moisture, then is heated further to its softening temperature. When at the softening temperature, the sheet is placed over the rocks, then vacuum is applied via the table to pull the sheet down over the rocks. Once thus formed to the shape of the rocks, the sheet is allowed to cool, then is taken off the table. Any rocks inadvertently captured in the molded sheet are removed.
This work was done by Joseph J. Kosmo of Johnson Space Center. For further information, access the Technical Support Package (TSP) free on-line at www.nasatech.com/tsp under the Materials category.