Shuttle Astronauts Use Robot Arm to Open Door

KENNEDY SPACE CENTER, Fla. — The space shuttle Discovery’s astronauts used an experimental 5-foot robot arm Sunday to unlock and open a hinged door in the cargo bay and to lift a small box.

Although there were some snags, the remote-control work went much more smoothly than the first workout two days earlier.

“It operated beautifully,” astronaut Stephen Robinson said.

This is the orbital debut of the $100-million Japanese arm, a prototype for the international space station. Astronauts could save considerable time by relying on such a device to perform precision, exterior work.

The jointed arm had little trouble unbolting and lifting the 1 1/2-foot box from its mounting brackets, and moving the box back and forth.

But during the door-opening test, the emergency brake automatically came on because of crossed computer signals, and Robinson and Jan Davis had to start all over again. They finally were able to get it to open the door, and the rest of the exercise went well.

“A few surprises, but the arm flew really well,” Davis said.

The U.S.-Canadian crew of six also spent its fourth day in space working with a vibration-isolating device and maintaining a safe yet communicative distance from an environmental satellite.

Trailing the space shuttle by 25 miles to 50 miles, the satellite is measuring 18 atmospheric gases, including those responsible for ozone depletion. As a bonus, scientists were trying to analyze a 5-mile-high cloud from a volcano on the Caribbean island of Montserrat.

The German-built satellite is supposed to spend nine days flying free of Discovery. The astronauts will retrieve it Saturday for the trip home.