Ultrasound on Discovery arm; Endeavour tiles hit
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: March 8, 2006
The shuttle Discovery's robot arm is undergoing ultrasound inspections after a weekend mishap in which a moveable access bucket bumped into the arm during work to clean up broken glass. Two small indentations were found underneath the arm's insulation blankets and NASA wants to make sure the underlying structure wasn't damaged. At the same time, engineers are assessing tile damage to the shuttle Endeavour's body flap caused by equipment that slipped off a tray used by workers inspecting the ship's rudder/speed brake.
"While they were doing that, they dropped some equipment off the tray," said Jessica Rye, a NASA spokeswoman. "What they dropped was a film processor, it struck the left hand side of the body flap. There was some tile damage on the body flap, which they're addressing. They're looking, of course, at structural inspections to evaluate if there is any structural damage to the body flap."
In Discovery's hangar (OPF Bay 3), meanwhile, engineers are continuing inspections of the shuttle's 50-foot-long robot. Friday night, engineers servicing the shuttle's heat shield tiles broke a light fixture. During work to vacuum up the fragments, a telescoping bucket used to move technicians from point to point in the cargo bay bumped into the robot arm.
Insulation blankets were removed and engineers spotted apparent damage to an aluminum grounding strap that runs the length of the arm. In addition, there are two small indentations in the arm's so-called outer bumper, an epoxy honeycomb material that protects the arm's underlying carbon composite structure. One indentation is .115 inches deep and 1 inch long and the other is .035 inches deep and a half-inch long.
During Discovery's upcoming mission, the shuttle arm will be used to pick up a long boom equipped with cameras and laser sensors to inspect the shuttle's heat-shield system after launch. In addition, two astronauts will ride about on the end of the boom during the first of three planned spacewalks as part of an engineering study to evaluate the extended arm-boom system's stability. The idea is to find out if the system could be used for heat-shield repair work if such work is ever needed.
To help evaluate the loads on the arm-boom system, Discovery's robot arm has been instrumented and engineers want to make sure the arm itself and the instrumentation were not damaged by the work bucket incident.
As of this writing, the arm damage does not appear to be a threat to the shuttle schedule, but engineers won't know for sure until the ultrasound tests are complete.