New Mars Rover Inspired by Sahara Desert Lizard Can 'Swim' Through Sand

Nature appears to have provided the optimal solution for navigating the extreme environment of the Red Planet. To effectively explore Mars, rovers must navigate vast expanses of sand. To tackle this challenge, German engineers have developed a new ground rover that uses a swimming-like motion to traverse sand, which typically causes conventional robot wheels to get stuck. The design is inspired by the African sandfish (Scincus scincus), a lizard renowned for diving into the Sahara Desert and literally ‘swimming’ through sand like a fish in water. A test video released this week by Würzburg University shows a silver-coloured, mini-fridge-sized robot moving nimbly across a test surface designed to mimic Mars’ sandy terrain. Rather than rolling forward like conventional car wheels, each of the four wheels cuts through the sand with a undulating motion forming an eight-shaped pattern. The robot moves forward several metres, then makes sharp turns and returns to its starting point steadily. ‘These wheels mimic the animal’s [sandfish] characteristic interaction with the ground, generating both longitudinal and lateral forces simultaneously,’ said Amenosis Lopez, a researcher at Würzburg University, in a statement. ‘The robot leaves a sinusoidal wave pattern in the sand.’ To most people, the image of space robots is of large circular wheels or caterpillar tracks reminiscent of the WALL-E character. However, in reality, both designs are less than ideal for Mars’ sandy and rugged terrain. Sand is a unique material with dual properties: it behaves like both a solid and a liquid simultaneously. Moreover, rovers exploring Mars must navigate steep slopes, rugged terrain, and uneven surfaces where varying sand density can cause robots to lose balance. Areas with overly soft sand pose a serious threat to round wheels, as the risk of the robot becoming buried and completely immobilised is ever-present. However, the sandfish lizard has solved this problem through millions of years of evolution. Despite its name including ‘fish’, this native Sahara creature is actually a skink lizard.