The Boeing Space Shuttle program joined with United Space Alliance (USA) and NASA to conduct its most significant debris tests since the Columbia Accident Investigation Board"smoking gun" test where a large piece of foam created a hole in a Reinforced Carbon-Carbon (RCC) panel.

The phase III RCC Impact testing began in late August and lasted several months at Southwest Research Institute (SWRI). But this time when engineers shot debris at a flight RCC panel, they were looking for validation of their damage prediction models.

RCC Panel 9, located at the heat critical region of the Shuttle's wing, is one of 22 panels on each wing leading edge that protect the Space Shuttle from temperatures as high as 3,000 degrees Fahrenheit during reentry into the earth's atmosphere. Panel 9 was the focus of impact tests at SWRI to finalize validation of the damage prediction models being developed by Boeing.

Few full panel tests have been conducted because of the limited availability of the RCC material and long lead time for replacement panels. A majority of the RCC panel testing to date has used smaller flat six-inch by six-inch coupons. Results from these coupon impact tests have supported preliminary damage model development and validation.

Debris tests include foam, ice and ablator materials (heat insulator material similar to cork) fired from a nitrogen-pressurized cannon. Debris testing with tiles has been ongoing for almost a year, while the long procurement lead-time for the RCC flat test coupons has delayed start of impact testing until recently.

A flight qualified RCC Panel 16, further outboard on the wing, was tested in August '04 in a full system test configuration. Boeing, USA, and NASA are analyzing the data from these tests.

"We fired several shots at the panel in different locations to determine if one location has more impact capability than another," said Valery Aksamentov, Boeing project manager for RCC damage assessment. "The test and analysis are closely linked together to validate our modeling capabilities."

Aksamentov says the analysis and testing was ready for NASA review and board certifications in January. He added additional testing would be conducted after STS-114 (the first flight after Columbia ) to further refine the models.

"It is both exciting and challenging and this test is the culmination of our efforts. We want to be ready for return to flight, and ensure that we fly safely," he concluded.

Boeing personnel from Houston, Texas, Huntington Beach, Calif.; Seattle, Wash.; Kennedy Space Center, Fla.; and Philadelphia, Pa., are involved in the tests.