Tuesday, February 2nd was a real treat for students and professors alike at our neighboring Aerospace Engineering Building. Here, the aerospace department hosted a special speaker: Astronaut Charles J. Camarda, who spoke on the Columbia Shuttle investigations. Deputy Director of Advanced Project for NASA, Dr. Camarda achieved a two-fold purpose of inspiring students and informing faculty with his speech. He met with students at 9:30 and at 4 pm gave his talk. The talk was encouraging as it presented successes resulting from diligent effort toward careers and multi-million dollar investigations with closing remarks about the social scientific habitat.

Dr. Camarda's educational and research track was referred to as a model for undergraduates to follow as it contained a balance of both research and higher education. He began research in the summer at NASA Langley as an intern, and then proceeded to find work that agreed to subsidize his graduate studies. Through this experience he decided to go into research and has since built an impressive resume beginning in a TPS position, and continuing to administrator, astronaut, special projects, space flight, and finally his current position as deputy director. He opened the talk by commenting on the importance of researchers as people. Quoting a colleague, he said, “People are the Prime Resource,” in an effort to guide students in the audience. Later on, he would address social aspects of scientific work and its impact on lives.

His most recent adventure was the return to flight mission, STS-114, which was the final test for solutions obtained from the Columbia Shuttle investigations. On this mission they tested some repairing procedures by repairing panels and seeing how well they withstood re-entry into the atmosphere.

Since the recovery of shuttle fragments (40% recovered), efforts focused on determining damage done to the leading edge of the shuttle wing by foam impact. The leading edge is made of reinforced carbon-carbon (RCC) panels, which is a strong material whose impact resistance was unknown. Consequently, impact testing commenced. Upon confirming that vacuum impact yielded same results as measurements at atmospheric pressure, tests were first carried out using small pieces of foam shot at small square pieces of RCC. At 400 feet per second (fps), there was not much damage, but material gave way at the expected shuttle speed of 700 fps.

With these tests complete, a real scale finite element model was undertaken to model the shuttle leading edge under foam impact. This is an enormous computational task, and it confirmed the results of the small scale testing on the actual scale model. As a final touch, scientists decided to test an actual panel (at cost $1 million per panel). A pressurized tube shot foam at 700 fps and the same breakage pattern was observed. Confident of these results, scientists proceeded to make modifications and discuss repair techniques.

Foam was first removed from the bipod region from where it fell off on Columbia. Then, re-entry conditions were also modeled for an RCC panel with cracks and it was determined that cracks grew allowing excessive heating of the region inside the wing's leading edge.

Solutions included re-caulking observed cracks in space using newly designed caulking guns, and plugs for larger cracks. The plugs were a concern as during re-entry flow would break over the discontinuity between the edge of the plug and the surface of the shuttle and cause excessive heating. STS 114 astronauts took cracked panels up into space, repaired them and came back safely. The integrity of the caulking material is now under investigation, while the repair procedures were deemed successful.

Finally, Dr. Camarda referred to a book which was a case study on the social causes of the Challenger crash. He emphasized that students should have faith in their knowledge and speak up to their supervisors if they are concerned about any safety or other matters. The talk ended with emphasis on openness and courage, as well as good news such as the total low cost of the shuttle investigation (less than $30 million).