Mars Pathfinder Wheel Abrasion Experiment - Ground and flight results

The Mars Pathfinder conducted scientific and technology experiments with a rover and a lander One of the technology experiments carried by the rover w as a tribological experiment, called the wheel abrasion experiment, designe d to evaluate the abrasiveness of Martian surface material. The experiment was carried on one of the wheels of the rover; Sojourner. Wear was detected by a photodetector through the reduction of reflectance of three types of metal films (Al, Pt, and Ni) on a black anodized substrate attached to the wheel. The Pathfinder mission showed that significant wear occurred on the metal wheel strips, with the most wear on the thinnest aluminum samples, mi d the least on the thickest nickel and platinum samples. The depth of dig d uring a wheel abrasion experiment showed that the surface material is, in s ome places, very loose, and in other places tightly packed. Laboratory test s using a spare flight wheel demonstrated that the surface simulants used f or wear testing adhered to the wheel and that electrostatic charging of the wheel occurred.