From the Sojourner rover, which landed on Mars in 1997, to Perseverance, which touched down in February, the robots of the Red Planet share a defining feature: wheels. Rolling is far more stable and energy efficient than walking, which even robots on Earth still struggle to master. After all, NASA would hate for its very expensive Martian explorer to topple over and flail around like a turtle on its back.
The problem with wheels, though, is that they limit where rovers can go: To explore complicated Martian terra like steep hills, you need the kinds of legs that evolution gave animals on Earth. So a team of scientists from ETH Zurich in Switzerland and the Max Planck Institute for Solar System Research in Germany have been playing around with a small quadrupedal robot called SpaceBok, designed to mimic an antelope known as a springbok.
True to its name, a real-life springbok bounces around the deserts of Africa, perhaps to confuse predators. The original concept for the robot, which was introduced in 2018, was actually for it to jump on the surface of the moon, as astronauts have done to locomote in the weak lunar gravity. That may work on our satellite, where the landscape is relatively flat, but on Mars it’s probably too risky given the complex terrain—which is full of sand, rocks, and steep slopes. So now the researchers are modifying its limbs and gaits to see if it might be able to handle more brutal landscapes.