A research team at Texas A&M University, led by graduate student Rishi Jangale and former NASA engineer Robert Ambrose, has unveiled the spherical robot 'RoboBall' in IEEE Transactions on Field Robotics, introducing a novel method for traversing treacherous terrain at the Moon's south pole.
Engineering for Extreme Lunar Terrains
RoboBall III is an inflatable robot measuring 1.8 meters in diameter and weighing 150 kg, purpose-built to survey steep slopes such as Shackleton Crater—a formation 21 km wide and 4 km deep. Astronauts cannot safely enter this permanently shadowed crater, despite it harboring ancient geological strata and critical deposits of water ice. Sara Russell, a cosmic mineralogist at the Natural History Museum in London, noted that the Moon serves as an archive of Earth's early history, making robotic sample retrieval exceptionally valuable for planetary science.
Pendulum-Driven Locomotion
Unlike conventional wheeled rovers prone to overturning in low-gravity environments, RoboBall operates by shifting an internal pendulum to alter its center of gravity. This mechanism allows the sphere to propel forward, steer, and brake while descending steep inclines. Hiro Ono, an aerospace engineer at the Georgia Institute of Technology and a 13-year veteran of NASA JPL, praised its streamlined design, which relies on just two actuators sealed entirely inside the outer shell. This architecture fully isolates the drive unit from abrasive lunar dust and extreme temperatures ranging from -240°C to over 93°C.
Field Testing and Future Development
During field tests at a Texas quarry, RoboBall III—upgraded with 2.5 times more torque—traversed wet clay, climbed 20-degree slopes, and successfully test-fired miniature sample-return rockets back up toward the crater rim. Built at a cost of approximately $250,000, the robot currently utilizes surface-treated aluminum parts but has not yet reached commercial space-grade flight readiness. Its outer shell withstands temperatures down to -184°C and sharp rock abrasion, though it has not yet been tested in a space-grade vacuum.
The Texas A&M team stated that upcoming development will focus on slope-adaptive autonomous navigation algorithms and optimizing the internal payload bay to accommodate standard geological analysis instruments.