Using automated handymen in space.

Satellites are easier to handle in space than on Earth, but a lot harder to control. In the friction-less, free-fall environment of space, moving a huge satellite requires no more than a push. Guiding it, however, creates immensely difficult problems for humans accustomed to the dynamics of objects on Earth.

Scientists working at Stanford University's Automated Robotics Laboratory may have come up with a solution-robots that can build space stations, rescue satellites, and perform repairs on spacecraft. The $12,000,000 project, a joint venture with NASA, plans to put a fully operational robot in space in three to five years.

In a lab designed to simulate space, Kurt Zimmerman, a doctoral student in electrical engineering, demonstrates how the robot is to function in space. From his computer terminal, he commands it to capture another object. The resulting show looks like a scene straight out of "Star Wars." Floating smoothly across a granite surface, the robot follows the target object. It stretches its long arms, and the probes at the end of the robot's arms latch on to predetermined spots on the slowly spinning target item.

The robot will maneuver in space with the help of cold-gas thrusters. Sensors will detect color patterns or a light source on targets like satellites. After an astronaut points the robot in the direction of the target satellite from a remote station, it will...