Report sheds light on physical and organizational causes of Columbia space shuttle accident

JOM, Oct 2003

A breach in the space shuttle Columbia's thermal protection system caused the shuttle to break apart upon reentering the Earth's atmosphere on February 1, 2003, but long-standing organizational issues within NASA contributed to the shuttle's failure, according to a report issued by the Columbia Accident Investigation Board in late August.

"The Board recognized early on that the accident was probably not an anomalous, random event, but rather likely rooted to some degree in NASA's history and the human space flight program's culture," the board wrote in the report's executive summary.

The physical cause of the accident was identified as a breach in the shuttle's Thermal Protection System, which consists of heat-resistant tiles, blankets, and reinforced carbon-carbon (RCC) panels. The leading edge of the shuttle's wing and the nose, which are subjected to air temperatures of 1,540[degrees]C-1,650[degrees]C, are protected by the RCC panels, which are layers of special graphite cloth. The large external tank of the space shuttle, which is discarded after a space shuttle's launch, holds extremely cold liquid oxygen and liquid hydrogen. To keep these propellants cold without allowing ice to form on the surface of the tank, the external tank is coated with a layer of insulating foam. A piece of this foam separated from the external tank following the space shuttle's launch on January 16, 2003, and struck one of the RCC panels on the left wing, creating an opening in the thermal protection system. As the plane reentered the Earth's atmosphere on February 1, 2003, this breach allowed superheated air to penetrate the insulation on the leading edge of the wing and progressively melt the aluminum structure of the left wing. This weakened the structure until increasing aerodynamic forces caused loss of control, failure of the wing, and finally, break-up of the shuttle.

The investigation board's report indicated that organizational and cultural issues that had developed over time within NASA could have led to the physical failure of the shuttle.

Upon receiving the report on August 26, NASA Administrator Scan O'Keefe announced that NASA intended to comply with the full range of recommendations in the report and had already begun by establishing the NASA Engineering Safety Center at NASA's Langley Research Center in Hampton, Virginia. The center is designed to provide a central location to coordinate and conduct agency-wide engineering and safety assessment.

On September 8, the agency released NASA 's Implementation Plan for Return to Flight and Beyond, a blueprint for acting on the Columbia Accident Investigation Board's 29 recommendations, including both short-term goals that will be accomplished before the agency returns to flight, as well as long-term goals that improve the entire human space (light program.

An in-depth article from NASA and others on the materials issues involved in the shuttle's break up will appear in the February 2004 issue of JOM.