In a history that includes technical setbacks and failures, the National Aeronautics and Space Administration has always bounced back with a solution over the four decades of human space flight. But its discovery that large pieces of foam fell off the shuttle Discovery's external fuel tank during Tuesday's launch shows that the space agency failed to solve the most basic problem that caused the Columbia accident that killed seven astronauts on their return voyage in February 2003. The Columbia burned up over Texas when superheated gases penetrated its wing. NASA then spent more than two years and $1.4 billion trying to improve safety. However, the recommendations made by Columbia's accident investigators never forced NASA to confront the problem head-on. The board told the space agency to “initiate” a program to eliminate foam debris and “initiate” a program to strengthen the orbiter's thermal protection system, but it never forced NASA to adopt a 100 per cent fix to either system. It also appears that in 2003, NASA rejected efforts by outside experts who proposed comprehensive fixes to the foam problem, because the proposals required aggressive redesigns or advanced foam technology that may have required significant investments. The path NASA took instead was to fix, at limited cost, an old launch system that it planned to get rid of by the end of the decade. Admiral Harold Gehman, chairman of the Columbia Accident Investigation Board, acknowledged that the recommendations to NASA left open a window that would have allowed the same scenario of foam debris falling off and damaging the orbiter’s thermal protection system. “We had precious little faith that they could stop this stuff from coming off,” Gehman said. “And lo and behold, they couldn't.” John Logsdon, director of the space policy institute at George Washington University and another member of the Columbia board, acknowledged that in hindsight the board should have issued a tougher recommendation on fixing the foam. Even NASA officials acknowledged that they erred. “We decided it was safe to fly as is. Obviously, we were wrong,” Bill Parsons, manager of the shuttle program, said Wednesday. But outside experts in 2003 tried to get NASA’s attention on advanced research they thought might help the space agency to keep the foam stuck to the tank. Steven Nutt, senior associate dean for research at the University of Southern California and head of the engineering department's Composite Center for foam research, submitted a proposal in 2003 to NASA for a fiber reinforced foam that his team had developed. Nutt said NASA never had the information necessary to decide whether his technology would work on the shuttle. He added, “I don't want to bad mouth NASA. I feel really sorry for those guys.” A second outside proposal submitted by Oscar Weingart, a materials science expert who had spent a career in composites, suggested winding tiny lightweight filaments around the external tank. The concept would have used 800 pounds of carbon filament to create a strong net around the foam, costing less than $1 million. Several academic experts in materials technology said the proposal looked promising. Weingart, who holds five patents for filament technology, said he received a brief letter thanking him. LAT-WP
