Bio-Inspired ‘Sandfish’ Wheels Enable New Mars Rover Mobility

A team at the University of Würzburg built a Mars rover with wheels that swim through sand. The prototype, part of the German Aerospace Center’s VaMEx program, was tested on sand and an open field with German Research Center for Artificial Intelligence (DFKI) in Bremen and University of Bremen.

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Mars rovers often become immobilized in loose sand, limiting missions. The Sahara sandfish lizard (Scincus scincus) can dive beneath the surface and move through material with minimal resistance. Biomechanical analysis of its locomotion motivated engineers to replicate its force generation in rover wheels.

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The effort is led by scientist Marco Schmidt, Professor of Embedded Systems and Sensors for Earth Observation (ESSEO) at University of Würzburg, with researcher Amenosis Lopez as co-investigator. The project is coordinated under German Aerospace Center’s VaMEx initiative and involves DFKI Bremen and University of Bremen.

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Sandfish wheels were heavier and narrower than conventional pneumatic wheels, producing ground pressure and sinking. Redesigns widened the wheels and reduced mass, lowering pressure and slip. Field tests showed steady movement across sand, sinusoidal tracks confirming the swimming mechanism, and improved stability and control.

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Improved mobility could reduce rover entrapment risk, expand traversable terrain, and enable scientific study of dune fields that are avoided. Approach could enhance rover performance on Mars and other bodies with loose regolith.

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Amenosis Lopez emphasized that conventional wheels are optimized for low-speed driving and are prone to slip on soft ground. Marco Schmidt said the experiments yielded guidance for refinements. ESSEO team plans software-guided control that adapts wheel torque to slip conditions.

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• “Conventional wheel designs are often optimized for driving at low speeds and tend to slip, sink, or get stuck on soft ground,” — Amenosis Lopez, Researcher, University of Würzburg

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• “The experiments also provided us with clear pointers for improvements,” — Marco Schmidt, Professor, ESSEO, University of Würzburg

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• “The wheels mimic the animal’s characteristic interaction with the ground, generating both longitudinal and lateral forces. The rover leaves sinusoidal tracks in the sand – this confirms that the intended swimming mechanism has been achieved.” — University of Würzburg research team

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• “Further refinements to the wheel surface are likely to further improve performance on mixed terrain,” — ESSEO team

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Article reports gains but gives no quantitative data on traction, energy use, or speed; tests were under Earth gravity and pressure, leaving Martian performance unverified.

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Team will add algorithms to adjust wheel torque for slip and test surface-texture refinements in simulated Martian conditions before deployment.

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