Snakebots are unlike any robotic probe ever to be used for space missions. In order for a robot to mimic the movements of a biological snake, some special design features have to be used. NASA's snakebots are a model of the polybot developed by Mark Yim of Xerox Palo Alto Research Center. Polybots are robots that are able to change their shape in order to perform a variety of tasks. Snakebots will slither and dig underneath the soil for geological surveying, or coil up to carry tools for construction in space.
The main body of a snakebot consists of about 30, identical, hinge-like modules that are linked together in a chain. These modules are connected by a central spine and work together to perform various functions. The snakebot frame will be constructed out of a polycarbonate material and covered by an artificial skin to protect it from the Martian elements. Here's a closer look at a snakebot's architecture and individual modules:
- Electronics - Each snakebot will have a central computer, possibly located in the snakebot's head, that works in conjunction with smaller computers in each module. Wires will connect each module to its neighboring modules, creating a network of modules that work together as a unit. The wiring will also carry communications and power to and from the computer brain.
- Microcontrollers - These tiny computers will interpret signals from the main computer to control movement. In later models, they may be connected to a set of sensors to provide reflexes.
- Sensors - In later models, strain sensors may be added to the robot's metal-rib frame. These sensors will indicate if the snake is in contact with anything, where it's touching it and how hard the contact is.
- Motors - Two servomotors, which are like off-the-shelf hobby motors, will be used to move the various parts in each module. Each motor will be activated by a signal from the main processor.
- Wheels - Each module will be equipped with one wheel. The wheel won't be wholly responsible for transporting the snakebot -- it will only used to ease movement.
- Gears - Working in conjunction with the electronics, the gears will allow for movement of the hinges. This will give the snake the ability to coil, side-wind and inch-worm its way across the ground or wrap around objects.
- Camera - Small cameras attached to the snakebots will give NASA a never-before-seen view of the red planet.
- Connecting Rods - When one section begins to move, these ball-jointed connecting rods will pull and activate the section next to it.
Snakebots will be able to limit the weight of the spacecraft ferrying them to space. The snake-like design allows them to perform many tasks without a lot of extra equipment. "One of the many advantages of the snake-based design is that the robot is field-repairable," NASA engineer Gary Haith says. "We can include a bunch of identical spare modules with the snake on a space mission, and then we can fix the snakebot much easier than a regular robot that needs specific parts."
Unlike past robotic probes, snakebot will be very cheap. In contrast to the $135-million Mars Odyssey that was launched on April 7, 2001, snakebots will probably cost only a few hundred dollars each. In fact, the cost of the snakebot is so low that one researcher says there is a possibility of developing a toy version.