CAPE CANAVERAL, Fla. (AP) - With astronauts standing by like traffic cops, ground controllers nudged a 5-foot, experimental robot arm back and forth aboard space shuttle Discovery on Wednesday.
The crew watched every move from inside the cabin - just in case the 5-foot arm banged into something.
"We're kind of like the safety observers," explained shuttle commander Curtis Brown Jr.
Until Wednesday, the astronauts were the only ones to test Japan's $100 million arm, a prototype of what will fly on the future international space station to handle outside precision work. This flight is its space debut, and despite some snags, Japanese space agency managers say they're pleased with the results.
Earlier in the 11-day shuttle mission, now more than halfway over, astronauts Jan Davis and Stephen Robinson used the jointed, remote-controlled arm to lift a 11/2 -foot box and open a small, hinged door. Ground controllers skipped these tests and instead focused on simple movements.
Discovery's six crew members also kept close watch over an ozone-mapping satellite that they dropped off last week.
Despite the non-stop atmospheric measurements, scientists said they cannot make any inferences about the condition of Earth's ozone layer. They said they'll have to wait until they recover their on-board data recorders.
The astronauts are to retrieve the satellite on Saturday and return to Earth on Monday.