Intrepid robot set for Chernobyl mission

The robot, called Pioneer, rides on two caterpillar tracks and is equipped with three-dimensional vision, radiation detectors, a beefy gripping arm, and a bore for taking samples. Pioneer is more than 3 feet tall and will be used to map out the dangerous parts of the defunct, radioactive reactor facility within the aging sarcophagus.

Although robots themselves are nothing new, Pioneer has some new-fangled visual systems, including a three-camera system that will be used to help the robot navigate and create a visually rich three-dimensional model of the facility. SGI donated four graphics workstations to power the back end of the robot's vision system.

The robot was built by Carnegie Mellon University and Redzone Robotics, a company of roboticists from CMU, along with researchers from several government labs and the University of Iowa. Pioneer's ancestors include Houdini, a robot that's retrieving nuclear waste buried in tanks at Oak Ridge National Laboratory, and several robots that helped clean up Three Mile Island nuclear power plant.

Pioneer, the Mars Pathfinder's Soujourner rover, and robots sent out to neutralize terrorist bombs share a common purpose: They can function in environments too perilous for a human. In the case of Pioneer, that peril comes in the form of intense radiation that still lingers within Chernobyl, more than 13 years after the April 26, 1986, explosion that killed 32 people and left reactor number 4 a shattered wreck with a melted core.

The Soviet Union requested the robot in 1987, but export restrictions prevented RedZone initially from shipping it.

Now that the Cold War has ended and the Soviet Union has split, the rules changed. The robot has been shipped as part of the Energy Department's effort to help Ukraine clean up the site before closing it by the year 2000.

Pioneer will be used to map out the reactor facility, test the radioactivity, humidity, and temperature of the interior. The robot's tiny bulldozer fitting also will be used to clear debris out of the way for people and other robots.

3-D vision
One of the more sophisticated parts of the robot is its vision. Three cameras are housed within a lead-lined casing to protect them from radiation; mirrors guide the light into the secure camera housing, researchers said.

Two cameras--or in the case of humans, the two eyes--are needed to judge depth and therefore comprehend surroundings in three dimensions. Pioneer, however, uses three cameras, which gives it added help when dealing with horizontal surfaces such as tabletops, the robot designers said.

As it creeps along, Pioneer will generate a basic model like a wire mesh of its surroundings. Then, using the SGI workstations, the actual textures will be "painted" on the mesh, creating a three-dimensional virtual reality tour of the inside of the facility.

In addition, the robot will gather radiation data that will be overlaid on the virtual reality mockup, providing a clear visual indication of an otherwise invisible danger.

It's possible SGI may make the virtual Chernobyl available on the Web, SGI said.

Efforts to deal with the old reactor still are under way. The sarcophagus built around the reactor has confined most radioactive materials to the site, but in the long term, "its stability and the quality of its confinement are in doubt," according to a 1996 report by the International Atomic Energy Agency.

The reactor exploded in 1986, spreading uranium, iodine-131, and other radioactive materials to the surrounding land, according to the IAEA. The iodine, in particular, has been linked to an increase in thyroid cancer, although because it's a short-lived radioactive isotope, the surge in cases has tapered off.

The government relocated about 210,000 people to new, less contaminated areas.