New Satellite Problem Plagues Shuttle Crew

As if overheating, tilting and wobbling weren’t enough, a satellite that is supposed to be growing semiconductor film in space experienced more trouble Wednesday, forcing NASA to scrap part of the experiment.

It was the fourth day in a row that the space shuttle Endeavour’s astronauts had to contend with satellite problems. The latest glitch with the $25-million Wake Shield came as ground controllers were trying to resume production of semiconductor film after nearly a day of suspended operations.

A balky temperature controller on the Wake Shield prevented arsenic--a key film ingredient--from being deposited atom-by-atom on the back of the 12-foot, dish-shaped satellite. Ground controllers had to switch from automatic to manual control.

“It’s a little bit like a shower where you turn it on and it’s too hot, then you turn it and it’s too cold, and you have to work back and forth,” Alex Ignatiev, director of the semiconductor experiment, said in describing the manual temperature control.

By then, so much time had been lost that there was no chance all seven wafers of film could be grown before the astronauts retrieve the Wake Shield today.

By Wednesday afternoon, four film wafers had been grown, with a fifth and final sample planned. The quality of the film will not be known until Endeavour returns to Earth on Monday.

On Tuesday, the Wake Shield overheated and began tilting, and ground controllers had to shut the satellite down. Even then, the 4,300-pound steel satellite wobbled slightly and at one point may have spun or even flipped.

Monday’s release of the Wake Shield was hindered by a weak radio link between the satellite and ground control.