NASA's Developing Robotic "Hedgehogs" to Explore a Martian Moon

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Exploring micro-gravity climates like Mars, which has just 38 percent of the Earth's force, or its moon, Phobos, which has 1000 times less gravity than that, can be a challenge for rovers that rely on wheels or skittering legs for traction. That's why Stanford researchers plan to survey the Martian moon with an fleet of bounding, spiked spheres.

The Stanford team, led by Department of Aeronautics and Astronautics assistant professor Marco Pavone and working in conjunction with NASA's JPL, has developed the nearly completely autonomous system. It consists of the Phobos Surveyor, an orbiting mothercraft about the size of a coffee table, and a series of surface rovers, known as "hedgehogs"—even though they look more like sea urchins. The Surveyor will handle the large-scale data collection such as mapping the moon's surface and sampling its chemical composition with a gamma ray or neutron detector. It will also be responsible for guiding the individual rovers to their various destinations and act as an data link to scientists back on Earth. While humans would set the general destinations for each rover, much of the detailed directing would be handled by the Surveyor itself. "It's the next level of autonomy in space," Pavone said in a press statement.

The hedgehogs themselves may look menacing but are uniquely suited for Phobos' minimal gravitation effects. Instead of relying on wheels that can easily lose traction or become jammed with the moon's powdery soil, these rovers will hop, skip, and tumble their way across the surface—or more accurately, through the air just above it. Each rover incorporates a trio of internal spinning discs—each oriented along a different axis—to generate momentum and propel it along the moon's rough and rocky surface.


This system is still in development—early prototypes for both the Surveyor and Hedgehogs have been built—so it'll be a while before we see them bounding across the Martian moon. But, if successful on Phobos, it could be sent to explore other small celestial bodies like asteroids and passing comets. [Stanford University]