Snakes alive! Serpentine robots head for space

NASA engineers are developing a snake-like robot that could help to explore other worlds and perform construction tasks in space. The "snakebot" consists of a series of identical, hinge-like modules attached in a chain, that flex under computer control to propel the device.

The "snakebots" have many potential advantages over conventional wheeled vehicles and robotic manipulators. They are assembled from identical low-cost, lightweight modules and could continue to work if one module failed. They will not need a ramp to crawl off a landing craft and could be sealed in an artificial skin to avoid exposure to hostile environments.

"The snake will provide us with flexibility and robustness in space," says Gary Haith, lead snakebot engineer at NASA`s Ames research centre, in California`s Silicon Valley. "A snakebot could navigate over rough, steep terrain where a wheeled robotic rover would likely get stuck or topple."

Robotic serpents have many possible forms of movement. They can "inchworm" forwards, flip themselves backwards, coil and side-wind. "Future work will enable the snake to become a mast or a grasping arm," Haith adds.

Strain sensors inside the snake tell whether it is touching anything and, if so, with what force. "The key part of what we are striving for … is sensor-based control in which the robot uses its sensors to decide what to do,`" Haith says.

"We hope to write software that allows the snake to learn on its own through experience," he adds. "We hope it will learn are how to crawl from soft to hard surfaces, and to go over rough surfaces. We even hope to show that it can climb scaffolds and go into cracks.

"A snakebot is not as good at some jobs as other robots," Haith concedes, "but you get a lot more robot for the weight and the money".

The prototype snakebot is driven by small motors but the NASA engineers hope to make "muscles" out of tough, lightweight plastic or rubber materials that will bend when electricity is applied. The first snakebots could be ready for space travel within five years.