A summary of the NASA Glenn Ballistic Impact Lab contributions to the Columbia accident investigation

On February 1, 2003, the Space Shuttle Columbia broke apart during reentry resulting in the loss of 7 crewmembers and craft. For the next several months an extensive investigation of the accident ensued involving a nationwide team of experts from NASA, industry, and academia, spanning dozens of technical disciplines. The Columbia accident investigation board (CAIB), a group of experts assembled to conduct an investigation independent of NASA, concluded in August, 2003 that the cause of the loss of Columbia and its crew was a breach in the left wing leading edge reinforced carbon-carbon (RCC) thermal protection system initiated by the impact of thermal insulating foam that had separated from the orbiter's external fuel tank 81 seconds into that mission's launch. During reentry, this breach allowed superheated air to penetrate behind the leading edge and erode the aluminum structure of left wing which ultimately led to the breakup of the orbiter. Supporting the findings of the CAIB numerous ballistic impact testing programs were conducted to investigate and quantify the physics of external tank foam impact on the RCC wing leading edge material. These tests ranged from fundamental material characterization tests to full-scale Orbiter wing leading edge tests. Following the accident investigation, NASA turned its focus to returning the Shuttle safely to flight. Supporting this effort are many test programs to evaluate impact threats from various debris sources during ascent that must be completed for certifying the Shuttle system safe for flight. Researchers at the NASA Glenn Ballistic Impact Laboratory have conducted several of the impact test programs supporting the accident investigation and return-to-flight efforts. This paper summarizes those activities and highlights the significant accomplishments made by this group.