Booster controller, cracks examined

Atlantis at the pad last month

Engineers will decide whether to replace a thrust vector controller, an electronic box that controls the thrust angle of the right solid rocket booster. The device, which has a backup system, appeared not to be working correctly during a tanking test last month.

"It's just a matter of removing one box and sticking in another," said NASA spokesman George Diller.

Crews will also inspect and repair small foam cracks caused by contraction of the external tank during two scrubbed launches and one tanking test.

"Whenever you do a tanking test you get some cracking in the foam," said Diller said.