NASA and JPL are sending RATS to Mars to work as field geologists. A RAT is not quite a furry little friend, but rather a high-tech robot with diamond teeth, called a Rock Abrasion Tool (RAT).

One RAT will ride on each of the twin Mars Exploration Rovers, launching to Mars in the summer of 2003. These RATS will allow humans to remotely "crack open" rocks on Mars for the first time in the history of Mars exploration.

Stephen Gorevan, Chairman, Honeybee

"This is terribly exciting, but it's a little intimidating because no one has ever tried to get into a rock on Mars before," says Stephen Gorevan. Gorevan is the chairman of Honeybee, the small robotics contractor for the Rock Abrasion Tool that sits half a mile away from ground zero in New York City. Gorevan explains that past Mars missions to the surface had different science and technology objectives. " The Viking landers in the 1970's scooped up dirt on Mars and the Sojourner rover proved we could move around on Mars in 1997." Digging into a rock is the next step for the maturing Mars program.

Bringing a rock back from Mars or sending a human geologist comes with prohibitive costs, so sending the RAT is the next best thing. The tool will enable scientists to peer inside a rock, where they can analyze unweathered minerals and learn about the origins of rocks. Rick Paynter, deputy lead for Quality Assurance on the Mars Exploration Rover project at NASA's Jet Propulsion Laboratory, explains that the RAT will help "peel off the orange rind" and reveal new information about the evolution of Mars. It will also help with comparing rocks on Mars to rocks on Earth.

How the RAT Runs

View the RAT video

The Mars Exploration Rover will traverse Mars, find a rock that's interesting, nuzzle up to it, and maneuver its robotic arm to press the RAT up against the chosen rock. The RAT, which is the size of a soda can, will shave away the top layers of the rock. That process may take anywhere from 30 minutes to three hours to remove a round hole about 45 millimeters (1.5 inches) in diameter and 5 millimeters (1/8th inch) deep, depending on the texture of the rock.

It's more like an electric shaver than a drill, says Steve Kondos, contract technical manager at JPL . "The difference is, the shaver heads move in and out rather than being stationary - this takes less power. Power, energy, and mass are precious on the rover, so in order to be efficient, we shave the rock rather than drill it, which is power intensive."

The RAT Brushes Its Teeth

After the RAT shaves off part of a rock, it scurries aside via a Dr. Seuss-like arm device, which also holds a camera and chemical analysis tools to explore the newly exposed rock layers. Before it goes to grind another rock, it turns around and brushes its "teeth" against a RAT brush that acts like a shoe polisher as the RAT "teeth" spin against it to clear out leftover rock. The RAT is designed to grind away one rock, but could shave up to as many as 10 rocks.