The changes take effect Aug. 1, and O'Keefe said that over the next several weeks he will visit NASA offices to discuss them.

"This transformation will be an evolutionary process, exploring new ways to move forward and implement change," he said. "Doing so will enable us to take the next bold steps into space and rekindle the innovation and entrepreneurial skills that is our legacy to humankind."

In its report issues last week the president's commission on NASA said the agency needs to transform itself into a leaner, more focused agency.

The change creates several so-called mission directorates including:

_ Aeronautics research to study and develop aeronautical technologies for safe, reliable and efficient aviation systems.

_ Science, to carry out the exploration of the Earth, Moon, Mars and beyond; chart the best route of discovery; and continue Earth and space exploration. This combines research in the Earth and other planets.

_ Exploration systems, to develop capabilities and supporting research and technology that enable sustained and affordable human and robotic exploration in space. It includes the biological and physical research necessary to ensure the health and safety of crew during long duration space flight.

_ Space operations, to direct space flight operations, space launches and space communications.

There will also be two agency-wide priorities under a Safety and Mission Assurance Office and an Education Office.

The agency said its headquarters and field center offices will be aligned to improve communications and responsibility.