Changes extended to the top

NASA moved quickly after the Columbia accident to reshape parts of the organization to prevent the kind of insular decision making that led to the disaster.

An independent engineering task force was formed to set engineering standards for the entire space agency. A separate independent group was established to provide technical advice on safety issues.

A crucial change has been made at the top.

Michael Griffin became NASA administrator in April. His predecessor, Sean O'Keefe, was a fiscal disciplinarian who took over the space agency at a tumultuous time of shrinking budgets and chaotic overspending. O'Keefe had been deputy director of the Office of Management and Budget, where he oversaw management and preparation of the federal budget.

Griffin came from the heart of NASA's engineering tradition. In many ways, he is considered the quintessential rocket scientist.

Early in his career he was chief engineer at the space agency. He is the author of the textbook, "Space Vehicle Design." Before returning to NASA, he headed the space department at Johns Hopkins University's Applied Physics Laboratory.

Griffin made it clear within days of becoming administrator that engineering thoroughness and discipline would be the key to NASA's future.