A small armored sphere rolls swiftly across a craggy landscape. It comes to a sudden stop, perching on three telescoping legs and sprouting a long neck with an eye that can swivel around 360 degrees. The enemy opens fire, but bullets merely ricochet off the sphere’s exoskeleton as from yet another opening there emerges a gun, which — sensing heat and motion — takes aim and fires…

Such is battle as conceived by Ranjan Mukherjee, associate professor of mechanical engineering at Michigan State University, who has received patent 6,289,263 three weeks ago for a spherical robotic soldier.

The sphere is propelled by shifting its internal weight. Uses also include intelligence gathering, fire rescue or space exploration.

The patent abstract reads:

A spherical robot having a spherical body and a drive mechanism. The spherical body defines a cavity and a center. The drive mechanism is disposed within the cavity, coupled to the spherical body, wherein said drive mechanism includes a plurality of masses coupled to said body which are radially positionable within said cavity to create a moment about said center of said body, and is adapted to create a moment about the center of the body. This moment causes the body to rotate.